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Sample records for susceptible laboratory strain

  1. Comparison of the insecticide susceptibilities of laboratory strains of Aedes aegypti and Aedes albopictus

    OpenAIRE

    Andrea Gómez; Emilia Seccacini; Eduardo Zerba; Susana Licastro

    2011-01-01

    A susceptible strain of Aedes albopictus derived from the Gainesville strain (Florida, USA) was established in our laboratory. The larvicidal efficacies of the neurotoxic insecticides temephos, permethrin and the pure cis and trans-permethrin isomers and the microbial insecticide Bacillus thuringiensis israelensis (Bti) against Ae. albopictus were estimated and compared to a susceptible strain of Aedes aegypti. The larvicidal effect of insect growth regulator pyriproxyfen was also evaluated i...

  2. Comparison of the insecticide susceptibilities of laboratory strains of Aedes aegypti and Aedes albopictus

    Directory of Open Access Journals (Sweden)

    Andrea Gómez

    2011-12-01

    Full Text Available A susceptible strain of Aedes albopictus derived from the Gainesville strain (Florida, USA was established in our laboratory. The larvicidal efficacies of the neurotoxic insecticides temephos, permethrin and the pure cis and trans-permethrin isomers and the microbial insecticide Bacillus thuringiensis israelensis (Bti against Ae. albopictus were estimated and compared to a susceptible strain of Aedes aegypti. The larvicidal effect of insect growth regulator pyriproxyfen was also evaluated in both mosquito strains. The median lethal concentration/median emergency inhibition values for Ae. aegypti and Ae. albopictus, respectively, were: temephos, 3.058 and 6.632 ppb, permethrin, 3.143 and 4.933 ppb, cis-permethrin, 4.457 and 10.068 ppb, trans-permethrin, 1.510 and 3.883 ppb, Bti, 0.655 and 0.880 ppb and pyriproxyfen, 0.00774 and 0.01642 ppb. Ae. albopictus was more tolerant than Ae. aegypti to all six larvicides evaluated. The order of susceptibility for Ae. aegypti was pyriproxyfen > Bti > trans-permethrin > temephos > permethrin > cis-permethrin and for Ae. albopictus was pyriproxyfen > Bti > trans-permethrin > permethrin > temephos > cis-permethrin. Because both species can be found together in common urban, suburban and rural breeding sites, the results of this work provide baseline data on the susceptibility of Ae. albopictus to insecticides commonly used for controlling Ae. aegypti in the field.

  3. Comparison of the insecticide susceptibilities of laboratory strains of Aedes aegypti and Aedes albopictus.

    Science.gov (United States)

    Gómez, Andrea; Seccacini, Emilia; Zerba, Eduardo; Licastro, Susana

    2011-12-01

    A susceptible strain of Aedes albopictus derived from the Gainesville strain (Florida, USA) was established in our laboratory. The larvicidal efficacies of the neurotoxic insecticides temephos, permethrin and the pure cis and trans-permethrin isomers and the microbial insecticide Bacillus thuringiensis israelensis (Bti) against Ae. albopictus were estimated and compared to a susceptible strain of Aedes aegypti. The larvicidal effect of insect growth regulator pyriproxyfen was also evaluated in both mosquito strains. The median lethal concentration/median emergency inhibition values for Ae. aegypti and Ae. albopictus, respectively, were: temephos, 3.058 and 6.632 ppb, permethrin, 3.143 and 4.933 ppb, cis-permethrin, 4.457 and 10.068 ppb, trans-permethrin, 1.510 and 3.883 ppb, Bti, 0.655 and 0.880 ppb and pyriproxyfen, 0.00774 and 0.01642 ppb. Ae. albopictus was more tolerant than Ae. aegypti to all six larvicides evaluated. The order of susceptibility for Ae. aegypti was pyriproxyfen > Bti > trans-permethrin > temephos > permethrin > cis-permethrin and for Ae. albopictus was pyriproxyfen > Bti > trans-permethrin > permethrin > temephos > cis-permethrin. Because both species can be found together in common urban, suburban and rural breeding sites, the results of this work provide baseline data on the susceptibility of Ae. albopictus to insecticides commonly used for controlling Ae. aegypti in the field.

  4. Laboratory and field evaluation of entomopathogenic fungi for the control of amitraz-resistant and susceptible strains of Rhipicephalus decoloratus.

    Science.gov (United States)

    Murigu, Mercy M; Nana, Paulin; Waruiru, Robert M; Nga'nga', Chege J; Ekesi, Sunday; Maniania, Nguya K

    2016-07-30

    Rhipicephalus decoloratus causes serious economic losses in cattle industry every year in East Africa. Biological control using entomopathogenic fungi is seen as a promising alternative to chemical acaricides being used for their control. The pathogenicity of Metarhizium anisopliae and of Beauveria bassiana isolates was tested in the laboratory against amitraz-resistant and amitraz-susceptible strains of R. decoloratus. Unfed larvae were sprayed with conidial suspensions of 1×10(9) conidia ml(-1). Fungal isolates were pathogenic to R. decoloratus larvae, causing mortality of between 10.0 and 100% and between 12.1 and 100% of amitraz-susceptible and amitraz-resistant strains, respectively. The LT50 values of selected fungal isolates varied between 2.6-4.2days in amitraz-susceptible strain and between 2.8-3.9days in amitraz-resistant strain. The LC50 values varied between 0.4±0.1 and 200.0±60×10(3) conidia ml(-1) and between 0.1±0.1 and 200.0±31.0×10(3) conidia ml(-1) in amitraz-susceptible and amitraz-resistant strains, respectively. Metarhizium anisopliae isolate ICIPE 7 outperformed the other isolates and was selected for compatibility study with amitraz and field trial. ICIPE 7 was compatible with amitraz. In the field, four treatments including control, ICIPE 7 alone, amitraz alone and ICIPE 7/amitraz were applied on cattle. All the treatments significantly reduced the number of ticks on all the sampling dates: day 7 (F3,8=3.917; P=0.0284), day 14 (F3,8=9.090; P=0.0275), day 21 (F3,8=37.971; P=0.0001) and day 28 (F3,8=8.170; P=0.0016) compared to the control. Results of the present study indicate that ICIPE 7 can be used for the management of amitraz-resistant strain of R. decoloratus. Copyright © 2016 The Author(s). Published by Elsevier B.V. All rights reserved.

  5. Establishing quality control ranges for antimicrobial susceptibility testing of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus: a cornerstone to develop reference strains for Korean clinical microbiology laboratories.

    Science.gov (United States)

    Hong, Sung Kuk; Choi, Seung Jun; Shin, Saeam; Lee, Wonmok; Pinto, Naina; Shin, Nari; Lee, Kwangjun; Hong, Seong Geun; Kim, Young Ah; Lee, Hyukmin; Kim, Heejung; Song, Wonkeun; Lee, Sun Hwa; Yong, Dongeun; Lee, Kyungwon; Chong, Yunsop

    2015-11-01

    Quality control (QC) processes are being performed in the majority of clinical microbiology laboratories to ensure the performance of microbial identification and antimicrobial susceptibility testing by using ATCC strains. To obtain these ATCC strains, some inconveniences are encountered concerning the purchase cost of the strains and the shipping time required. This study was focused on constructing a database of reference strains for QC processes using domestic bacterial strains, concentrating primarily on antimicrobial susceptibility testing. Three strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) that showed legible results in preliminary testing were selected. The minimal inhibitory concentrations (MICs) and zone diameters (ZDs) of eight antimicrobials for each strain were determined according to the CLSI M23. All resulting MIC and ZD ranges included at least 95% of the data. The ZD QC ranges obtained by using the CLSI method were less than 12 mm, and the MIC QC ranges extended no more than five dilutions. This study is a preliminary attempt to construct a bank of Korean QC strains. With further studies, a positive outcome toward cost and time reduction can be anticipated.

  6. Establishing Quality Control Ranges for Antimicrobial Susceptibility Testing of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus: A Cornerstone to Develop Reference Strains for Korean Clinical Microbiology Laboratories

    Science.gov (United States)

    Hong, Sung Kuk; Choi, Seung Jun; Shin, Saeam; Lee, Wonmok; Pinto, Naina; Shin, Nari; Lee, Kwangjun; Hong, Seong Geun; Kim, Young Ah; Lee, Hyukmin; Kim, Heejung; Song, Wonkeun; Lee, Sun Hwa; Lee, Kyungwon; Chong, Yunsop

    2015-01-01

    Quality control (QC) processes are being performed in the majority of clinical microbiology laboratories to ensure the performance of microbial identification and antimicrobial susceptibility testing by using ATCC strains. To obtain these ATCC strains, some inconveniences are encountered concerning the purchase cost of the strains and the shipping time required. This study was focused on constructing a database of reference strains for QC processes using domestic bacterial strains, concentrating primarily on antimicrobial susceptibility testing. Three strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) that showed legible results in preliminary testing were selected. The minimal inhibitory concentrations (MICs) and zone diameters (ZDs) of eight antimicrobials for each strain were determined according to the CLSI M23. All resulting MIC and ZD ranges included at least 95% of the data. The ZD QC ranges obtained by using the CLSI method were less than 12 mm, and the MIC QC ranges extended no more than five dilutions. This study is a preliminary attempt to construct a bank of Korean QC strains. With further studies, a positive outcome toward cost and time reduction can be anticipated. PMID:26354353

  7. ANTIBIOTIC SUSCEPTIBILITY OF POTENTIALLY PROBIOTIC LACTOBACILLUS STRAINS

    Directory of Open Access Journals (Sweden)

    Junhua Han

    2015-09-01

    Full Text Available Susceptibility of 29 Lactobacilli to 13 antibiotics was assayed by paper disc diffusion method. Plasmids and gastrointestinal tolerance were detected. The relationship between plasmids andantibiotic resistance was discussed. The results showed that all of the strains were resistant to bacitracin, polymyxin B, kanamycin, and nalidixic acid. Many strains were relatively sensitive tochloramphenicol and tetracycline. Six strains contained plasmids and showed good gastrointestinal tolerance. β-lactam resistance gene blr was found in the plasmid of L. plantarum CICC 23180by PCR. The study will be helpful to promote the safety evaluation and development of potentially probiotic lactic acid bacteria.

  8. Harmonization of antimicrobial susceptibility testing among veterinary diagnostic laboratories in the five Nordic countries

    DEFF Research Database (Denmark)

    Petersen, A.; Aarestrup, Frank Møller; Hofshagen, Merete

    2003-01-01

    A total of 100 bacterial strains (25 Escherichia coli, 25 Salmonella enterica, 25 Staphylococcus aureus, and 25 Enterococcus strains) and four reference strains were tested for susceptibility toward 8-12 antimicrobial agents in 12 veterinary diagnostic laboratories in the five Nordic countries......, whereas for Enterococcus spp., two laboratories had less than 90 % concordant results. Susceptibility testing of Salmonella to fluoroquinolones gave rise to almost 0.5% nonconcordant results and susceptibility testing of S. aureus to vancomycin resulted in that 1.8% of the strains were incorrectly...... reported as vancomycin resistant. Ten laboratories identified the Enterococcus spp. to species level. All five Enterococcus faecium and 10 Enterococcus faecalis selected from the strain collection at the Danish Veterinary Institute were correctly identified by all laboratories, whereas some problems were...

  9. Susceptibility of laboratory rodents to Trichinella papuae.

    Science.gov (United States)

    Sadaow, Lakkhana; Intapan, Pewpan M; Boonmars, Thidarut; Morakote, Nimit; Maleewong, Wanchai

    2013-12-01

    Members of the genus Trichinella are small nematodes that can infect a wide range of animal hosts. However, their infectivity varies depending on the parasite and host species combination. In this study, we examined the susceptibility of 4 species of laboratory rodents, i.e., mice, rats, hamsters, and gerbils to Trichinella papuae, an emerging non-encapsulated Trichinella species. Trichinella spiralis and Trichinella pseudospiralis were also included in this study for comparison. Fifteen animals of each rodent species were infected orally with 100 muscle larvae of each Trichinella species. Intestinal worm burden was determined at day 6 and 10 post-inoculation (PI). The numbers of muscle larvae were examined at day 45 PI. The reproductive capacity index (RCI) of the 3 Trichinella species in different rodent hosts was determined. By day 6 PI, 33.2-69.6% of the inoculated larvae of the 3 Trichinella species became adult worms in the small intestines of the host animals. However, in rats, more than 96% of adult worms of all 3 Trichinella species were expelled from the gut by day 10 PI. In gerbils, only 4.8-18.1% of adult worms were expelled by day 10 PI. In accordance with the intestinal worm burden and the persistence of adults, the RCI was the highest in gerbils with values of 241.5±41.0 for T. papuae, 432.6±48 for T. pseudospiralis, and 528.6±20.6 for T. spiralis. Hamsters ranked second and mice ranked third in susceptibility in terms of the RCI, Rats yielded the lowest parasite RCI for all 3 Trichinella species. Gerbils may be an alternative laboratory animal for isolation and maintenance of Trichinella spp.

  10. SUSCEPTIBILITY OF BORDETELLA PERTUSSIS STRAINS TO ANTIBACTERIAL PREPARATIONS

    Directory of Open Access Journals (Sweden)

    O. Yu. Borisova

    2013-01-01

    Full Text Available 178 strains of B. pertussis isolated from infected individuals in various regions of Russia from 1948 to 2012 have been studied for their susceptibility to six antibacterial preparations. It has been shown, that B. pertussis strains isolated from 1948 to 1989 were predominantly sensitive to erythromycin. In the following years a gradual decrease in susceptibility of circulating strains of B. pertussis to this antibiotic was registered with the emergence of strains with intermediate susceptibility in 22% of cases from 1990 to 2005 (MIC 0,060 mcg/mL, up to 59,3% in the last six years (MIC 0,125 mcg/mL. As for azithromycin, high susceptibility of strains of B. pertussis to this preparation was shown throughout the entire duration of the survey. However, the rate of incidence of intermediate strains reached 14% among those strains isolated from 1990 to 2005, and is now at 32%. Thus, after several decades of active use of antibiotics pertussis underwent a series of transformations resulting in a decrease in susceptibility of B. pertussis strains to erythromycin and azithromycin.

  11. Antibiotics susceptibility pattern of Escherichia coli strains isolated ...

    African Journals Online (AJOL)

    This study was carried out to determine the susceptibility of E coli strains isolated from broiler and layer chicken with colisepticemia to antibiotics used in poultry industry in the country. A total of fifty seven E. coli strains isolated from 43 broiler and14 layer farms with colisepticemia in Khartoum and Gezera state were ...

  12. Antimicrobial Susceptibilities of Unique Stenotrophomonas maltophilia Clinical Strains

    Science.gov (United States)

    Valdezate, Sylvia; Vindel, Ana; Loza, Elena; Baquero, Fernando; Cantón, Rafael

    2001-01-01

    Susceptibility to 41 antimicrobials was studied with 99 Stenotrophomonas maltophilia strains, and different pulsed-field gel electrophoresis profiles were identified among 130 prospectively collected isolates. Moxalactam, doxycycline, minocycline, and clinafloxacin displayed the highest activity (≥98% susceptibility). Ticarcillin resistance (75%) was reverted by clavulanate in 25% of strains. Trimethoprim-sulfamethoxazole resistance was 26.2% (≥4 [trimethoprim]/76 [sulfamethoxazole] μg/ml) and dropped to 11.1% when an 8/152-μg/ml breakpoint was applied based on its bimodal MIC distribution. Resistance was lower when unique strains were considered, because clonal organisms contribute to resistance. PMID:11302834

  13. Draft Genome Sequence of Vancomycin-Susceptible, Ampicillin-Intermediate Enterococcus faecium Strain D344RRF

    OpenAIRE

    Garc?a-Solache, M?nica; Rice, Louis B.

    2016-01-01

    Enterococcus faecium is an important nosocomial pathogen, causing a substantial health burden due to high resistance to antibiotics and its ability to colonize the gastrointestinal tract. Here, we present the draft genome of vancomycin-susceptible, ampicillin-intermediate strain D344RRF, a rifampicin/fusidic acid-resistant and commonly used laboratory strain, which is useful in studying the transfer of antibiotic resistance.

  14. Susceptibility of laboratory and field-collected Aedes aegypti and Aedes albopictus to Bacillus thuringiensis israelensis H-14.

    Science.gov (United States)

    Lee, Y W; Zairi, J

    2006-03-01

    Susceptibility levels of a few laboratory-cultured and dengue-endemic area field-collected strains of Aedes aegypti and Aedes albopictus to Bacillus thuringiensis israelensis (Bti) at different storage ages were studied. The susceptibility of laboratory-cultured World Health Organization (WHO) Bora Bora reference, Vector Control Research Unit (VCRU), and Fumakilla Malaysia Berhad (FMB) strains of Ae. aegypti to Bti was examined. The sensitivity to Bti decreased with storage age. The median lethal concentration (LC50) for Bti increased by 2-3 times after 2 years compared to a fresh sample (3-6 months of storage). However, after the 2-year storage period, Bti still provided very good efficacy against all laboratory-cultured susceptible strains of Ae. aegypti and Ae. albopictus. The observed 95% lethal concentration values were about 20 times lower than the recommended concentration (6,000 international toxic units (ITU)/liter). Results obtained from the study against the dengue-endemic area field-collected strains of Ae. aegypti and Ae. albopictus confirmed the effectiveness of the Bti after storage for 2 years (18-24 months). For Ae. aegypti, the Ujung Batu strain was the most susceptible to Bti, whereas the Sungai Nibong strain showed the most tolerance. Susceptibility of laboratory-cultured strains varied; the Air Itam strain of Ae. albopictus was the most susceptible to Bti, whereas the Kampung Serani strain was the most tolerant among the field strains. However, the laboratory strain of Ae. albopictus was more susceptible than all the field strains.

  15. Antimicrobial drug susceptibility of Neisseria meningitidis strains isolated from carriers

    Directory of Open Access Journals (Sweden)

    Dayamí García

    2000-06-01

    Full Text Available When it is necessary to determine the susceptibility of Neisseria meningitidis (Nm strains to antimicrobial drugs, it is important to consider that it should be analyzed in a double context. One of them related to the use of drugs in a specific medical treatment; and the other; to chemoprophylatic drugs, both with the same purpose: the accurate selection of the “in vivo” antimicrobial agent. This requires the study of the sensitivity and resistance of strains isolated in both carriers and patients. With the aim of further studying the behavior of the strains that currently circulate in Cuba, an antimicrobial drug susceptibility study was conducted in 90 strains isolated from carriers during the first half of 1998. The agar dilution method was used to determine the minimum inhibitory concentrations (MICs to: penicillin, ampicillin, rifampin, sulfadiazine, chloramphenicol, ciprofloxacin, ceftriaxone, cefotaxime. The study of the three latter drugs was done for the first time in our country. The search for β- lactamase-producer strains was also performed. There was a predominance of penicillin sensitive strains (82,2% with an intermediate sensitivity to ampicillin (57,8%, while 70% of the strains were sensitive to sulfadiazine. Regarding the rest of the antimicrobial drugs, 100% of the strains were sensitive. The paper shows the MICs for each drug as well as the phenotypic characteristics of the strains with the penicillin and sulfadiazine sensitivity and resistance patterns. No β-lactamase-producer strains were found.

  16. SUSCEPTIBILITY OF Listeria monocytogenes STRAINS ISOLATED FROM FOOD TO ANTIMICROBIAL AGENTS

    Directory of Open Access Journals (Sweden)

    E. Zanardi

    2013-02-01

    Full Text Available The objective of this study was to evaluate the susceptibility of 40 L. monocytogenes strains isolated from seafood and processing environments to 19 antibiotics currently used in veterinary and human therapy. Susceptibility tests were performed by the automated system VITEK2. Apart from Penicillin, Ampicillin and Trimethoprim-Sulfamethoxazole, for which clinical breakpoint for Listeria susceptibility testing are defined according to the Clinical and Laboratory Standard Institute (CLSI, in the present study the CLSI criteria for staphylococci were applied. This study shows that isolated L. monocytogenes strains are susceptible to the antibiotics commonly used in veterinary and human listeriosis treatment. Very few strains (7,5% showed a resistance behaviour towards Oxacillin, whereas a variable pattern was showed for Ciprofloxacin and Moxifloxacin. Moreover, an increase in tetracycline resistance, reported by several authors, can not be confirmed in this study, probably due to the different sources of strains isolation. At last, the VITEK2 system represents a rapid and easy-to-use means for antimicrobial susceptibility test of Listeria monocytogenes. In conclusion, because of the increase of antimicrobial resistance showed by L. monocytogenes, a continuous surveillance of emerging antimicrobial resistance among this pathogen is important to ensure effective treatment of human listeriosis. These data can be used for improve background data on antibiotic resistance of strains isolated from food and food environment, even considering the lack of clinical breakpoint provided by the CLSI.

  17. antimicrobial susceptibility pattern of vibrio cholerae 01 strains

    African Journals Online (AJOL)

    hi-tech

    East African Medical Journal Vol. 77 No. 7 July 2000. ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF VIBRIO CHOLERAE 01 STRAINS DURING TWO CHOLERA OUTBREAKS IN DAR ES SALAAM,. TANZANIA. W.K. Urassa, MD, MSc, MMed, Lecturer, Department of Microbiology and Immunology, Muhimbili University ...

  18. antimicrobial susceptibility pattern of vibrio cholerae 01 strains

    African Journals Online (AJOL)

    hi-tech

    2000-07-07

    Jul 7, 2000 ... Literature on the antibiotic susceptibility of cholera organisms from most developing countries is patchy. Worldwide, V. cholerae 01 strains resistant to tetracycline, trimethoprim/sulphamethoxazole and ampicillin are common(6-10). In many of these studies, the main reasons for the rapid rise in antimicrobial ...

  19. [Antimicrobial susceptibility of Helicobacter pylori strains isolated from gastric lesions].

    Science.gov (United States)

    Pereyra, Laura Del V; Gorordo Ipiña, Rosa C; Berruezo, Fabiana A; Amieva, Cristian A; García, Maria E; Bottiglieri, Marina T

    Antimicrobial susceptibility was evaluated by two diffusion methods: E-test strips to determine minimum inhibitory concentration (MIC) and disk diffusion for amoxicillin, clarithromycin, metronidazole and ciprofloxacin in 30 Helicobacter pylori strains isolated from gastric biopsies. No strains were resistant to amoxicillin, 17% (5/30) were resistant to clarithromycin, 20% (6/30) ciprofloxacin by both methods, and 37% (11/30) to metronidazole by the E-test. Although the number of strains studied was reduced, there was a single mismatch in interpreting susceptibility when both methods were compared; the same mismatch was observed for metronidazole, being categorized as sensitive by the E-test and as intermediate by disk diffusion. No association between the histological type of lesion and the resistance pattern found could be determined. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  20. Antimicrobial susceptibility and typing of Neisseria gonorrhoeae strains from Southern Spain, 2012-2014.

    Science.gov (United States)

    Cobo, Fernando; Cabezas-Fernández, M Teresa; Cabeza-Barrera, M Isabel

    2016-01-01

    Gonorrhoea remains an important health problem worldwide. The latest European guidelines have recommended the introduction of dual antimicrobial therapy due to the increase in its resistance to antimicrobial agents. In the present study, the susceptibility to some antibiotics was evaluated, and the typing of Neisseria gonorrhoeae strains was also performed. All Neisseria gonorrhoeae (NG) strains isolated from January 2012 to October 2014 were included in this work. Gonococcal isolates were tested for susceptibility according to the recommendations of both the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST). A total of 65 isolates were typed by the NG multi-antigen sequence types (NG-MAST) technique. The most frequent types found were ST 1407, ST 5405, ST 2992, and ST 5120. If CLSI and EUCAST criteria were applied, an ST 9807 type was found non-susceptible to ceftriaxone and cefixime (MIC 0.5μg/mL). When only EUCAST breakpoints were taken into account, three strains were also resistant to cefixime (MIC 0.25μg/mL) and two isolates were resistant to ceftriaxone (MIC 0.19 and 0.25μg/mL, respectively). The majority of strains were resistant to ciprofloxacin, and all Neisseria gonorrhoeae strains were susceptible to spectinomycin; twenty-five percent of isolates were resistant to azithromycin. The implementation of antimicrobial surveillance programs at regional level should be part of an overall gonococcal infection control strategy. Efforts should be made to perform antimicrobial susceptibility, a "cured test" in all gonorrhoea cases, and identify treatment failures to verify emerging resistance. Some types have been associated with decreased susceptibility to cephalosporins, making molecular typing a useful tool to predict antimicrobial resistance. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  1. The Effect of Ivermectin in Seven Strains of Aedes aegypti (Diptera: Culicidae) Including a Genetically Diverse Laboratory Strain and Three Permethrin Resistant Strains

    Science.gov (United States)

    Deus, K. M.; Saavedra-rodriguez, K.; Butters, M. P.; Black, W. C.; Foy, B. D.

    2014-01-01

    Seven different strains of Aedes aegypti (L.), including a genetically diverse laboratory strain, three laboratory-selected permethrin-resistant strains, a standard reference strain, and two recently colonized strains were fed on human blood containing various concentrations of ivermectin. Ivermectin reduced adult survival, fecundity, and hatch rate of eggs laid by ivermectin-treated adults in all seven strains. The LC50 of ivermectin for adults and the concentration that prevented 50% of eggs from hatching was calculated for all strains. Considerable variation in adult survival after an ivermectin-bloodmeal occurred among strains, and all three permethrin-resistant strains were significantly less susceptible to ivermectin than the standard reference strain. The hatch rate after an ivermectin bloodmeal was less variable among strains, and only one of the permethrin-resistant strains differed significantly from the standard reference strain. Our studies suggest that ivermectin induces adult mortality and decreases the hatch rate of eggs through different mechanisms. A correlation analysis of log-transformed LC50 among strains suggests that permethrin and ivermectin cross-resistance may occur. PMID:22493855

  2. Susceptibility of Aedes albopictus Skuse (Diptera: Culicidae) to permethrin in Kuala Lumpur, Malaysia

    National Research Council Canada - National Science Library

    Othman Wan-Norafikah; Wasi Ahmad Nazni; Han Lim Lee; Pawanchee Zainol-Ariffin; Mohd Sofian-Azirun

    2013-01-01

    ...: The susceptibility status of laboratory susceptible strain, permethrin-selected strain, and four field strains of Aedes albopictus collected from Kuala Lumpur were determined using three standard...

  3. Antibiotic susceptibilities of genetically characterized Streptococcus milleri group strains.

    Science.gov (United States)

    Tracy, M; Wanahita, A; Shuhatovich, Y; Goldsmith, E A; Clarridge, J E; Musher, D M

    2001-05-01

    Previous studies of the antibiotic susceptibility of Streptococcus milleri group organisms have distinguished among species by using phenotypic techniques. Using 44 isolates that were speciated by 16S rRNA gene sequencing, we studied the MICs and minimum bactericidal concentrations of penicillin, ampicillin, ceftriaxone, and clindamycin for Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus. None of the organisms was resistant to beta-lactam antibiotics, although a few isolates were intermediately resistant; one strain of S. anginosus was tolerant to ampicillin, and another was tolerant to ceftriaxone. Six isolates were resistant to clindamycin, with representation from each of the three species. Relatively small differences in antibiotic susceptibilities among species of the S. milleri group show that speciation is unlikely to be important in selecting an antibiotic to treat infection caused by one of these isolates.

  4. Variation in susceptibility of laboratory and field strains of three stored-grain insect species to beta-cyfluthrin and chlorpyrifos-methyl plus deltamethrin applied to concrete surfaces

    Science.gov (United States)

    The efficacy of beta-cyfluthrin and chlorpyrifos-methyl plus deltamethrin applied to clean, concrete floors of empty bins prior to grain storage against field strains of stored-grain insects is unknown. We exposed adults of 16 strains of the red flour beetle, Tribolium castaneum (Herbst); 8 strains ...

  5. SUSCEPTIBILITY TEST FOR FUNGI: CLINICAL AND LABORATORIAL CORRELATIONS IN MEDICAL MYCOLOGY

    Directory of Open Access Journals (Sweden)

    Ana ALASTRUEY-IZQUIERDO

    2015-09-01

    Full Text Available SUMMARYDuring recent decades, antifungal susceptibility testing has become standardized and nowadays has the same role of the antibacterial susceptibility testing in microbiology laboratories. American and European standards have been developed, as well as equivalent commercial systems which are more appropriate for clinical laboratories. The detection of resistant strains by means of these systems has allowed the study and understanding of the molecular basis and the mechanisms of resistance of fungal species to antifungal agents. In addition, many studies on the correlation of in vitro results with the outcome of patients have been performed, reaching the conclusion that infections caused by resistant strains have worse outcome than those caused by susceptible fungal isolates. These studies have allowed the development of interpretative breakpoints for Candida spp. and Aspergillus spp., the most frequent agents of fungal infections in the world. In summary, antifungal susceptibility tests have become essential tools to guide the treatment of fungal diseases, to know the local and global disease epidemiology, and to identify resistance to antifungals.

  6. Susceptibility of adult field strains of Aedes aegypti and Aedes albopictus in Singapore to pirimiphos-methyl and permethrin.

    Science.gov (United States)

    Ping, L T; Yatiman, R; Gek, L P

    2001-06-01

    The susceptibilities of field strains (Fl) of Aedes aegypti and Ae. albopictus adult females to pirimiphos-methyl and permethrin were investigated and compared with a susceptible laboratory strain (S) by using a filter paper (12 x 15 cm) impregnation method. The resistance ratio between the 50% lethal concentration values (RR50) of the Fl and the S strains shows that the RR50 of Fl Ae. aegypti for pirimiphos-methyl was 1.5 and the RR50 of Fl Ae. aegypti for permethrin was 12.9. The RR50 of Fl Ae. albopictus for pirimiphos-methyl was 1.4, and that for permethrin was 1.8. This indicates that the field strain Ae. aegypti, but not Ae. albopictus, has developed resistance to permethrin. However, both species are still susceptible to pirimiphos-methyl. Therefore, control with pirimiphos-methyl will still be effective.

  7. [Antibiotic susceptibility of community-acquired strains ofstaphylococcus aureus in Nouakchott Region (Mauritania)].

    Science.gov (United States)

    Salem, Mohamed Lemine Ould; Ghaber, Sidi Mohamed; Baba, Sidi El Wafi Ould; Maouloud, Mohamed Mahmoud Ould

    2016-01-01

    Staphilococcus aureus is a leading pathogen for humans causing a variety of infections such as skin, urinary tract and lung infections as well as sepsis. This study aims to evaluate the susceptibility of community-acquired strains of Staphylococcus aureus, isolated from various pathological products, compared with major antibiotics used in Nouakchott Region (Mauritania). We conducted a retrospective study of 281 strains of Staphylococcus aureus strains isolated from various pathological products from non-hospitalized patients in the National referral hospital laboratory and in two private laboratories in the city of Nouakchott between January 2014 and August 2015. Antibiotic sensitivity was determined by disk diffusion method using agar containing Mueller-Hinton medium according to CA-SFM's recommendations. The resistance rate to penicillin G was high (96-100%). Community-acquired MRSA rate was between 25 and 26% in suppurations, 34.3% in urine cultures and 28% in sperm cultures. Macrolide -Lincosamyne-streptogramins (MLS) resistance, giving rise to the phenotype MLSb inducible, was found in 6% of urinary strains and 27% of strains isolated from suppurations. The activity of aminoglycosides was variable, amikacin was active against all strains. Cotrimoxazole activity was low (77% had resistance) and no vancomycin resistance was reported. The activity of penicillin G against Staphylococcus aureusstrains isolated in Nouakchott region is almost zero and community-acquired MRSA rate is high, accounting for 34%. This could be explained by uncontrolled use of these molecules in our country.

  8. In-vitro susceptibility of methicillin-resistant Staphylococcus aureus strains to antibiotics

    Directory of Open Access Journals (Sweden)

    İsmail Güler

    2011-12-01

    Full Text Available Objectives: Methicillin resistance of S.aureus strains sourced from hospitals and community-acquired has been increasing. The aim of this cross-sectional study is to determine the resistance rates to alternative antibiotics of meticilline resistant S.aureus (MRSA strains, where the multiple resistances are encountered the most.Materials and methods: A total of 100 MRSA strains isolated consequently from the clinical samples of hospitalized patients in Erciyes University Medical Faculty Hospitals between September 2008 and October 2009 were included in the study. According to “Clinical and Laboratory Standards Institude (CLSI” criteria, antimicrobial susceptibility testing was performed by Kirby-Bauer disk diffusion method.Results: The rates of resistance to antibiotics of the MRSA strains included within the study were 77% to erythromycin, 1% to trimethoprim/sulfamethoxazole (TMP-SXT, 90% to rifampin, 63% clindamycin, 84% to gentamicin and 0% to teicoplanin and vancomycin.Conclusion: All MRSA strains were susceptible to vancomycine and teicoplanin. On the other hand, TMP-SXT seems to be alternative agent for treatment of MRSA infections.

  9. Antimicrobial susceptibilities of Listeria monocytogenes human strains isolated from 1970 to 2008 in Brazil.

    Science.gov (United States)

    Reis, Cristhiane Moura Falavina dos; Barbosa, André Victor; Rusak, Leonardo Alves; Vallim, Deyse Christina; Hofer, Ernesto

    2011-01-01

    Listeria monocytogenes is the causative agent of listeriosis, a foodborne illness that affects mainly pregnant women, the elderly and immunocompromised patients. The primary treatment is a combination of ampicillin with an aminoglycoside, in addition to a second-choice drug represented by chloramphenicol, erythromycin, tetracycline and rifampicin. The aim of this study was to analyze the antimicrobial susceptibility profile of strains isolated from human sources in the last four decades. Sixty-eight strains were selected from the culture collection of the Laboratory of Bacterial Zoonoses/LABZOO/FIOCRUZ isolated in different regions of Brazil from 1970 to 2008 and primarily isolated from cerebrospinal fluid and blood culture. Susceptibility tests to antimicrobials drugs were evaluated using the criteria established by Soussy using the Kirby-Bauer method and E-Test strips were used to determine the minimum inhibitory concentration (MIC). Among the strains tested, serovar L4b (60.3%) was the most prevalent, followed by serovar 1/2a (20.6%), 1/2b (13.2%) and the more uncommon serovars 1/2c, 3b and 4ab (5.9%). All strains were susceptible to ampicillin, cephalothin, erythromycin, gentamicin, teicoplanin and vancomycin. Only one strain (1.5%) showed resistance to rifampin, and two (3%) were resistant to trimethoprim-sulfamethoxazole. MICs with values up to 2 μg/ml reinforce the need for microbiological surveillance. The study demonstrated low prevalence of strains resistant to the antimicrobial drugs indicated in the treatment of human listeriosis. Monitoring antimicrobial resistance profile is still very important to determine adequate treatment, especially in immunocompromised patients.

  10. Antimicrobial susceptibilities of Listeria monocytogenes human strains isolated from 1970 to 2008 in Brazil

    Directory of Open Access Journals (Sweden)

    Cristhiane Moura Falavina dos Reis

    2011-04-01

    Full Text Available INTRODUCTION: Listeria monocytogenes is the causative agent of listeriosis, a foodborne illness that affects mainly pregnant women, the elderly and immunocompromised patients. The primary treatment is a combination of ampicillin with an aminoglycoside, in addition to a second-choice drug represented by chloramphenicol, erythromycin, tetracycline and rifampicin. The aim of this study was to analyze the antimicrobial susceptibility profile of strains isolated from human sources in the last four decades. METHODS: Sixty-eight strains were selected from the culture collection of the Laboratory of Bacterial Zoonoses/LABZOO/FIOCRUZ isolated in different regions of Brazil from 1970 to 2008 and primarily isolated from cerebrospinal fluid and blood culture. Susceptibility tests to antimicrobials drugs were evaluated using the criteria established by Soussy using the Kirby-Bauer method and E-Test strips were used to determine the minimum inhibitory concentration (MIC. RESULTS: Among the strains tested, serovar L4b (60.3% was the most prevalent, followed by serovar 1/2a (20.6%, 1/2b (13.2% and the more uncommon serovars 1/2c, 3b and 4ab (5.9%. All strains were susceptible to ampicillin, cephalothin, erythromycin, gentamicin, teicoplanin and vancomycin. Only one strain (1.5% showed resistance to rifampin, and two (3% were resistant to trimethoprim-sulfamethoxazole. MICs with values up to 2μg/ml reinforce the need for microbiological surveillance. CONCLUSIONS: The study demonstrated low prevalence of strains resistant to the antimicrobial drugs indicated in the treatment of human listeriosis. Monitoring antimicrobial resistance profile is still very important to determine adequate treatment, especially in immunocompromised patients.

  11. Study of Different Effects of Nets Impregnated with Different Pyrethroids on Susceptible and Resistant Strains of Anopheles stephensi

    Directory of Open Access Journals (Sweden)

    M.H. Hodjati

    2006-10-01

    Full Text Available Introduction & Objectives: A laboratory study was carried out to investigate the insecticidal, irritant and anti-feeding effects of nets treated with various pyrethroids against susceptible and highly pyrethroid resistant strains of An. stephensi. Materials & Methods: Tests were carried out inside a mosquito cage measuring 25×25×25 cm where mosquitoes were offered the opportunity to feed blood on an arm through the top face of the cage which had been pyrethroid treated.Results: With all the pyrethroids tested, the resistant strain spent a longer time in contact with a treated net, which was in contact with a human arm, than did the susceptible strain. With permethrin the resistant strain fed significantly more successfully through the treated netting than did the susceptible strain. With deltamethrin there was a non-significant tendency in the same direction in comparing the two strains. However, with alphacypermethrin there was a non-significant tendency in the reverse direction. After 15 min in the cage which tested for the ability to feed through a pyrethroid treated net, observed mortality was higher with the susceptible than the resistant strain. Conclusion: Thus there was no sign that the longer resting of the resistant strain on treated netting would compensate for the fact that a higher dose was needed to kill this strain. Such compensation had been suggested with the West African An. gambiae where treated nets continue to work well against a highly resistant wild population. However this does not seem to apply to our resistant An. stephens.

  12. Clinical Antibiotic-resistant Acinetobacter baumannii Strains with Higher Susceptibility to Environmental Phages than Antibiotic-sensitive Strains

    OpenAIRE

    Chen, Li-Kuang; Kuo, Shu-Chen; Chang, Kai-Chih; Cheng, Chieh-Chen; Yu, Pei-Ying; Chang, Chih-Hui; Chen, Tren-Yi; Tseng, Chun-Chieh

    2017-01-01

    Antibiotic-resistant Acinetobacter baumannii is associated with nosocomial infections worldwide. Here, we used clinically isolated A. baumannii strains as models to demonstrate whether antibiotic resistance is correlated with an increased susceptibility to bacteriophages. In this study, 24 active phages capable of infecting A. baumannii were isolated from various environments, and the susceptibilities of both antibiotic-sensitive and antibiotic-resistant strains of A. baumannii to different p...

  13. In vitro antimicrobial susceptibility of Staphylococcus aureus strains from dairy herds in KwaZulu-Natal.

    Science.gov (United States)

    Schmidt, T

    2011-06-01

    Staphylococcus aureus is 1 of the most important causes of bovine mastitis and is responsible for significant economic losses to the dairy industry worldwide. One of the principal approaches used in treating intramammary infections is the administration of antimicrobials. Due to the propensity of S. aureus to develop resistance, antimicrobial susceptibility monitoring is necessary to ensure that treatment regimens are effective. As part of this investigation, 90 S. aureus strains isolated from mastitis cases submitted to Allerton Provincial Veterinary Laboratory during 2008 and 2009 were evaluated for their susceptibility to a panel of 10 antimicrobials. Only 8 of the 90 S. aureus isolates tested (8.9%) were found to be susceptible to all of the antimicrobials evaluated. A very high level of resistance to the beta-lactam antibiotics was noted: 47.8% of the isolates were resistant to penicillin and 65.6% were resistant to ampicillin. Minimal resistance to oxacillin, cephalothin and trimethoprim-sulfamethoxazole (1.1%) was found. Seventeen (18.9%) of the isolates tested were found to be resistant to 3 or more antimicrobials. The need for vigilant monitoring of bacterial resistance trends in the dairy industry is warranted as the potential public health implications are significant.

  14. Increased rate of penicillin non-susceptible strains of N. meningitidis in Naples, Italy.

    Science.gov (United States)

    Di Caprio, Giovanni; Carannante, Novella; Bernardo, Mariano; Cuccurullo, Susanna; Pallotto, Carlo; Tascini, Carlo

    2017-07-20

    Neisseria meningitidis is a causative agent of community-acquired sepsis and meningitis in humans. These diseases are associated with high mortality and morbidity if treatment is not started promptly. The empiric antibiotic treatment depends on patient factors and local epidemiology. In the past years, an increased number meningococcal strain with reduced susceptibility to penicillin has also been described. We analysed the susceptibility pattern of 11 N. meningitidis strains isolated between 2013 and 2016. Only three (27%) strains were fully susceptible to penicillin, suggesting that a third-generation cephalosporin, instead of penicillin, as empiric therapy is more reliable when an invasive meningococcal disease is suspected.

  15. RAPD Analysis and Antibiotic Susceptibility for Mycobacterium tuberculosis Strains Isolated from Different Locations in Egypt

    Directory of Open Access Journals (Sweden)

    Ali, A. M.

    2011-01-01

    Full Text Available The routine identification of mycobacterial strains isolated from patients in different locations in Egypt was confirmed by specific DNA fragment amplification. The susceptibilities of 72 Mycobacterium tuberculosis strains against the four antibiotics used in tuberculosis treatment (Isoniazid, INH; Rifampicin, Rif; Streptomycin, St and Ethambutol, E were examined. Our results indicated that, multi drug resistant tuberculosis (MDR-TB represents about 19.5% of the tested strains, whereas sensitive strains represented 26.4%. The genetic polymorphism of the tested strains was examined using RAPD analysis. Six selected strains represent the different antibiotic susceptibility groups were examined using RAPD fingerprinting. No difference between the strains was recorded using the RFLP analysis of amplified specific fragment. The discrimination power of RAPD analysis was inadequate to clarify the genetic correlation between the tested strains. MDR-TB was approximately double time in 2008 compared with the value in 2007. Most of the new MDRTB was correlated with resident dense population regions.

  16. Clinical Antibiotic-resistant Acinetobacter baumannii Strains with Higher Susceptibility to Environmental Phages than Antibiotic-sensitive Strains.

    Science.gov (United States)

    Chen, Li-Kuang; Kuo, Shu-Chen; Chang, Kai-Chih; Cheng, Chieh-Chen; Yu, Pei-Ying; Chang, Chih-Hui; Chen, Tren-Yi; Tseng, Chun-Chieh

    2017-07-24

    Antibiotic-resistant Acinetobacter baumannii is associated with nosocomial infections worldwide. Here, we used clinically isolated A. baumannii strains as models to demonstrate whether antibiotic resistance is correlated with an increased susceptibility to bacteriophages. In this study, 24 active phages capable of infecting A. baumannii were isolated from various environments, and the susceptibilities of both antibiotic-sensitive and antibiotic-resistant strains of A. baumannii to different phages were compared. In our study, a total of 403 clinically isolated A. baumannii strains were identified. On average, the phage infection percentage of the antibiotic-resistant A. baumannii strains was 84% (from 81-86%), whereas the infection percentage in the antibiotic-sensitive A. baumannii strains was only 56.5% (from 49-64%). In addition, the risk of phage infection for A. baumannii was significantly increased in the strains that were resistant to at least four antibiotics and exhibited a dose-dependent response (p-trend baumannii isolates, 75.6% were phage typeable. The results of phage typing might also reveal the antibiotic-resistant profiles of clinical A. baumannii strains. In conclusion, phage susceptibility represents an evolutionary trade-off in A. baumannii strains that show adaptations for antibiotic resistance, particularly in medical environments that have high antibiotic use.

  17. In vitro susceptibility to mecillinam of Escherichia coli strains isolated from the urine of pregnant women.

    Science.gov (United States)

    Duployez, C; Loiez, C; Cattoen, C; Descamps, D; Wallet, F; Vachée, A

    2016-12-01

    Pivmecillinam is a safe beta-lactam for use in pregnancy. It has been widely used for the treatment of lower urinary tract infections (UTIs) in the Nordic countries where its efficacy, minor impact on the microbiota, and low level of resistance among the Escherichia coli strains have been proven. However, susceptibility data related to E. coli involved in asymptomatic bacteriuria and lower UTIs in pregnant women is lacking. We aimed to support the 2015 recommendations issued by the French Infectious Diseases Society (SPILF) on gestational UTI, with a particular focus on pivmecillinam. Antimicrobial susceptibility testing was performed by 12 hospitals with a maternity department on 235 E. coli strains isolated from the urine of pregnant women. Susceptibility to mecillinam was tested by disk diffusion method using the 2015 recommendations of the antibiogram committee of the French microbiology society (CA-SFM). Global susceptibility to mecillinam was 86.4%. Susceptibility to mecillinam was 96.5% for strains susceptible to amoxicillin-clavulanic acid and 38.7% for resistant strains. All six extended-spectrum beta-lactamase-producing E. coli strains were susceptible to mecillinam. Given the efficacy and safety of pivmecillinam during pregnancy, it may be used for the documented treatment of asymptomatic bacteriuria and acute cystitis in pregnant women. It also represents an alternative for the treatment of multidrug-resistant bacterial infections. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Antimicrobial susceptibility pattern of Vibrio cholerae 01 strains ...

    African Journals Online (AJOL)

    Results: A total of 181 V. cholerae 01 strains were studied during two epidemic periods when tetracycline or erythromycin was used for treatment of patients with severe disease. Among the 94 V. cholerae Ol strains isolated in 1997; 98.6%, 93.6%, 83%, 81.9%, 36.2%, 35.5%, 3.2% were sensitive to ciprofloxacin, tetracycline, ...

  19. [Determination of in vitro susceptibilities of Brucella spp. strains against 11 different antibacterial gents isolated from blood cultures].

    Science.gov (United States)

    Keşli, Recep; Bilgin, Hüseyin; Yılmaz, Halim

    2017-07-01

    Brucellosis is a worldwide zoonotic disease and still continuous to be a major public health problem. In this study, it was aimed to identify the Brucella strains to the species level isolated from blood cultures, and to determine the rate of antimicrobial susceptibility against eleven antibacterial agents. A total of 106 Brucella spp. strains were included in the study, which were isolated from blood cultures in University of Health Sciences, Konya Training and Research Hospital, Medical Microbiology Laboratory between January 2011 and June 2013. Identification of the isolated strains were mainly based on conventional methods. In vitro antibacterial susceptibilities of azithromycin, ciprofloxacin, doxycycline, gentamicin, levofloxacin, moxifloxacin, rifampicin, streptomycin, tetracycline, tigecycline, and trimethoprim/sulfamethoxazole, were evaluated by using the gradient (E-test, bioMerieux, France) strip method. The bacterial suspensions adjusted to 0.5 McFarland turbidity was inoculated to Mueller Hinton agar plates, supplemented with 5% sheep blood, and E-test strips of selected antibacterial were applied. The plates were incubated in ambient air 48 hours at 37ºC and Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213 were used as quality control strains for antimicrobial susceptibility testing. Minimum inhibitors concentration (MIC) values were interpreted according to Clinical and Laboratory Standards Institute (CLSI) guidelines for slow-growing bacteria such as Haemophilus spp. Of the 106 Brucella spp. strains included in to the study, 90 were identified as Brucella melitensis, and 16 were Brucella abortus. MIC90 values of azithromycin, ciprofloxacin, doxycycline, gentamicin, levofloxacin, moxifloxacin, rifampicin, streptomycin, tetracycline, tigecycline, and trimethoprim/sulfamethoxazole were determined as 1 µg/ml, 0.25 µg/ml, 0.19 µg/ml, 0.25 µg/ml, 0.19 µg/ml, 0.75 µg/ml, 0.25 µg/ml, 0.75 µg/ml, 0.38 µg/ml, 0.64 µg/ml, and 0

  20. [Determination of hemolytic activity and in vitro antifungal susceptibility of Trichophyton rubrum clinical strains].

    Science.gov (United States)

    Solgun, Gülkan; Fındık, Duygu; Türk Dağı, Hatice; Arslan, Uğur

    2011-01-01

    Trichophyton spp. which are among the agents of dermatophytosis with high morbidity, produce many virulence factors including hemolysins that exhibit toxic activity on immune system cells. Since relapses and chronicity are common problems related to dermatophytosis, prompt and appropriate treatment is of crucial importance. However, treatment is getting difficult due to the choice of inappropriate antifungals and increasing rates of cross-resistance among antifungal agents. The aims of this study were to investigate the hemolytic activities of Trichophyton rubrum strains isolated from patients with dermatophytosis and to detect the in vitro susceptibilities of those strains to ketoconazole, itraconazole, sulconazole, econazole and terbinaphine. Hair, skin and nail samples of patients were examined with direct microscopy using potassium hydroxide and cultivated on mycobiotic agar and Sabouraud dextrose agar. To determine hemolytic activities of T.rubrum strains, they were subcultured in Columbia Agar with 5% sheep blood and incubated for 7-14 days at 25°C in aerobic conditions. Media which displayed hemolysis were further incubated for 1-5 days at 37°C to increase hemolytic activity. Antifungal susceptibility testing was done with broth microdilution method guided by Clinical and Laboratory Standards Institute (CLSI) M38-A document. A total of 79 T.rubrum strains which exhibited negative urease and hair perforation tests, yielded pigmentation in potato-dextrose agar, were evaluated in the study. Hemolytic activity was detected in 71 strains (89.9%). Fifty strains showed incomplete (alpha) hemolysis and 21 strains showed complete (beta) hemolysis, whereas hemolysis was absent in eight of the isolates. Larger colonies created a larger zone of hemolysis and the smaller ones created a smaller zone. However, alpha-hemolysis did not turn to beta-hemolysis following further enlargement of the colony. According to antifungal susceptibility testing, the minimum inhibitory

  1. A preliminary linkage map using spotted melanic laboratory strains ...

    Indian Academy of Sciences (India)

    Sección Genética Evolutiva, Facultad de Ciencias, UdelaR, Iguá 4225, CP 11400 Montevideo, Uruguay. [Gutiérrez M. L. and García G. 2011 A preliminary linkage map using spotted melanic laboratory strains of the livebearing fish. Phalloceros caudimaculatus var. reticulata (Cyprinodontiformes: Poeciliidae). J. Genet.

  2. Genomic diversity among Corynebacterium jeikeium strains and comparison with biochemical characteristics and antimicrobial susceptibilities.

    Science.gov (United States)

    Riegel, P; de Briel, D; Prévost, G; Jehl, F; Monteil, H

    1994-08-01

    Levels of DNA relatedness were determined by performing DNA-DNA hybridization experiments (S1 nuclease procedure) with 13 human isolates exhibiting various antimicrobial susceptibility patterns which had been identified as Corynebacterium jeikeium by classical tests and the API Coryne system and with reference strains of C. jeikeium and related taxa. Twelve of 13 isolates which formed three genomic groups showed between 22 and 75% relatedness with the type strain of C. jeikeium. One of these genomic groups included all the strains resistant to penicillin and gentamicin and is genomically related to the C. jeikeium type strain at the species level. In addition, the reference strain of "Corynebacterium genitalium" biotype II was found to belong to this genospecies and therefore can be considered as a synonym of C. jeikeium. In contrast, one isolate and the reference strains of "Corynebacterium pseudogenitalium" biotypes C-3 and C-4 which were assigned to C. jeikeium by the API Coryne system were less than 10% related to the C. jeikeium type strain. These nongenomically related strains can be differentiated from the jeikeium-related strains on the basis of positive acidification from fructose and growth under anaerobic conditions. Furthermore, these strains exhibited full susceptibility to penicillin whereas the strains related to the C. jeikeium type strain are resistant to or only moderately susceptible to penicillin. No genomic relationship was found between C. jeikeium-related strains and other lipophilic coryneforms, identified as Corynebacterium accolens or Corynebacterium group G or F. Our study demonstrates the necessity to perform the fructose fermentation test or respiratory-type test for the correct identification of lipophilic coryneforms as C. jeikeium. Although these strains show genomic diversity at the species level, in a practical aspect, biochemical properties as well as antimicrobial susceptibility may allow the classification of such isolates in

  3. A laboratory yeast strain suitable for spirit production.

    Science.gov (United States)

    Schehl, Beatus; Müller, Christine; Senn, Thomas; Heinisch, Jürgen J

    2004-12-01

    Yeast strains of the species Saccharomyces cerevisiae currently in use for the production of consumable alcohols such as beer, wine and spirits are genetically largely undefined. This prevents the use of standard genetic manipulations, such as crossings and tetrad analysis, for strain improvement. Furthermore, it complicates the application of the majority of modern methods developed in yeast molecular biology. Here we used two haploid laboratory strains with suitable auxotrophic markers for the construction of a genetically well defined, prototrophic diploid production strain. This strain was tested for its fermentative and sensory performances in comparison to commercially available yeasts. Three different fruit mashes (cherries, plums and pears) were fermented in a 90 kg scale. These were then subjected to distillation and used for the production of spirits with a final ethanol content of 40% (v/v). Fermentation parameters assayed included growth, sugar utilization, ethanol production and generation of volatile compounds, higher alcohols and glycerol. The spirits were also tested for their sensory performances and the data obtained statistically consolidated. Our results clearly demonstrate that this laboratory strain does not display any disadvantage compared with commercial yeasts in spirit production for any of the parameters tested, yet it offers the potential to apply both classical breeding and modern molecular genetic techniques for adjusting yeast physiology to special production schemes.

  4. Frequent major errors in antimicrobial susceptibility testing of bacterial strains distributed under the Deutsches Krebsforschungszentrum Quality Assurance Program.

    Science.gov (United States)

    Boot, R

    2012-07-01

    The Quality Assurance Program (QAP) of the Deutsches Krebsforschungszentrum (DKFZ) was a proficiency testing system developed to service the laboratory animal discipline. The QAP comprised the distribution of bacterial strains from various species of animals for identification to species level and antibiotic susceptibility testing (AST). Identification capabilities were below acceptable standards. This study evaluated AST results using the DKFZ compilations of test results for all bacterial strains showing the number of participants reporting the strain as resistant (R), sensitive (S) or intermediate susceptible (I) to each antibiotic substance used. Due to lack of information about methods used, it was assumed that what the majority of the participants reported (R or S) was the correct test result and that an opposite result was a major error (ME). MEs occurred in 1375 of 14,258 (9.7%) of test results and ME% ranged from 0% to 23.2% per bacterial group-agent group combination. Considerable variation in MEs was found within groups of bacteria and within groups of agents. In addition to poor performance in proper species classification, the quality of AST in laboratory animal diagnostic laboratories seems far below standards considered acceptable in human diagnostic microbiology.

  5. 49 Marked susceptibility of South African Helicobacter pylori strains ...

    African Journals Online (AJOL)

    clarithromycin, tetracycline, amoxicillin, gentamicin, ciprofloxacin and erythromycin. H. pylori was isolated following standard microbiology procedures, and susceptibility determined using the Kirby-Bauer disc diffusion and agar dilution methods. Comparisons of antimicrobial resistance rates with sex of the patients were ...

  6. Comparison of Antimicrobial Susceptibility of Campylobacter Strains Isolated from Food Samples and Patients with Diarrhea.

    Science.gov (United States)

    Bakhshi, Bita; Naseri, Amin; Alebouyeh, Masoud

    2016-01-01

    Campylobacter infections may lead to serious conditions, including septicemia or other invasive forms of the disease, which require rapid and accurate laboratory diagnosis and subsequently appropriate antimicrobial therapy. The aim of this study was to compare the species distribution and antimicrobial susceptibility pattern of Campylobacter spp. strains isolated from patients and food samples. Biochemical identification was performed on 15 clinical and 30 food isolates of Campylobacter recovered onto Brucella agar containing 5% sheep blood. PCR was carried out to confirm the identity of Campylobacter spp. using primers for cadF, hipO, and asp genes of Campylobacter. To determine antibiotic sensitivity of isolates, Kirby-Bauer assay was carried out using 16 different antibiotic discs. PCR assay and biochemical tests confirmed all 45 isolates as Campylobacter: 20 (44.44%) as C. jujeni, 10 (22.22%) as C. coli, and 15 (33.34%) as other Campylobacter strains. The maximum resistance was observed to cefotaxime and imipenem (each 86.49%) and the maximum sensitivity to erythromycin (48.65%). C. jujeni is dominant among isolates from clinical and food samples. In addition, tetracycline remains the first-line therapeutic agent against Campylobacter infections in Iran.

  7. [The susceptibility of Proteus mirabilis strains isolated from white stork (Ciconia ciconia)].

    Science.gov (United States)

    Kwiecińska-Piróg, Joanna; Bogiel, Tomasz; Gospodarek, Eugenia; Kasprzak, Mariusz; Jerzak, Leszek; Kamiński, Piotr

    2011-01-01

    Proteus sp. rods are ubiquitous bacteria, widespread in the environment and classified also as opportunistic human pathogens. The aim of our study was to evaluate susceptibility of Proteus mirabilis strains isolated from white stork (Ciconia ciconia) regarding as his natural bacterial flora, compare and discuss their results with data obtained from scientific literature for clinical strains of the same species. Susceptibility of 59 P. mirabilis strains was estimated for 27 antimicrobials using disc-diffusion method and the ability to produce extended spectrum beta-lactamases was evaluated by double disc synergy test. Environmental P. mirabilis strains isolated from white stork were assessed as more susceptible to most of the examined antimicrobials and production of extended spectrum beta-lactamases was not noted amongst them.

  8. Variation in susceptibility of field strains of three stored grain insect species to spinosad and chlorpyrifos-methyl plus deltamethrin on hard red winter wheat.

    Science.gov (United States)

    Sehgal, Blossom; Subramanyam, Bhadriraju; Arthur, Frank H; Gill, Bikram S

    2013-08-01

    Spinosad and chlorpyrifos-methyl plus deltamethrin efficacy at labeled rates on hard red winter wheat were evaluated against 11 field strains of the red flour beetle, Tribolium castaneum (Herbst); six strains of the sawtoothed grain beetle, Oryzaephilus surinamensis (L.); and two strains of the lesser grain borer, Rhyzopertha dominica (F.), collected mostly from farm-stored grain in Kansas. Adults were exposed to wheat treated with spinosad at 1 mg (active ingredient)/kg or chlorpyrifos-methyl plus deltamethrin at three plus 0.5 mg (active ingredient)/kg. Adult mortality was assessed after 7 and 14 d and progeny production after 42 d. Spinosad did not provide complete mortality or progeny suppression of T. castaneum and O. surinamensis field strains, but was effective against R. dominica strains. Chlorpyrifos-methyl plus deltamethrin produced complete mortality and progeny suppression of field strains all three species. The two least susceptible T. castaneum and O. surinamensis strains and the two R. dominica strains were chosen for dose-response tests only with spinosad. The LD99 values for T. castaneum and R. dominica field strains were similar to that of the corresponding laboratory strains. Corresponding values for the two O. sturinamensis field strains were significantly greater (approximately 6 times) than the laboratory strain. The effective dose for progeny reduction (ED99) of only one R. dominica field strain was significantly greater (approximately 2 times) than the laboratory strain. The baseline susceptibility data of field strains of three insect species to spinosad will be useful for monitoring resistance development when this product is commercially released as a grain protectant.

  9. Laboratory strains of Aedes aegypti are competent to Brazilian Zika virus.

    Directory of Open Access Journals (Sweden)

    André Luis Costa-da-Silva

    Full Text Available The Zika virus outbreaks are unprecedented human threat in relation to congenital malformations and neurological/autoimmune complications. Since this virus has high potential to spread in regions presenting the vectors, improvement in mosquito control is a top priority. Thus, Aedes aegypti laboratory strains will be fundamental to support studies in different research fields implicated on Zika-mosquito interactions which are the basis for the development of innovative control methods. In this sense, our aim was to determine the main infection aspects of a Brazilian Zika strain in reference Aedes aegypti laboratory mosquitoes. We orally exposed Rockefeller, Higgs and Rexville mosquitoes to the Brazilian ZIKV (ZIKVBR and qRT-PCR was applied to determine the infection, dissemination and detection rates of ZIKV in the collected saliva as well as viral levels in mosquito tissues. The three strains sustain the virus development but Higgs showed significantly lower viral loads in bodies at 14 days post-infection (dpi and the lowest prevalences in bodies and heads. The Rockefeller strain was the most susceptible at 7 dpi but similar dissemination rates were observed at 14 dpi. Although variations exist, the ZIKVBR RNA shows detectable levels in saliva of the three strains at 14 dpi but is only detected in Rockefeller at 7 dpi. Moreover, saliva samples from the three strains were confirmed to be infectious when intrathoracically injected into mosquitoes. The ZIKVBR kinetics was monitored in Rockefeller mosquitoes and virus could be identified in the heads at 4 dpi but was more consistently detected late in infection. Our study presents the first evaluation on how Brazilian Zika virus behaves in reference Aedes aegypti strains and shed light on how the infection evolves over time. Vector competence and hallmarks of the ZIKVBR development were revealed in laboratory mosquitoes, providing additional information to accelerate studies focused on ZIKV

  10. Antimicrobial susceptibility pattern of Vibrio cholerae 01 strains ...

    African Journals Online (AJOL)

    Conclusion: Significant proportion of V. cholerae 0l strains in Dar es Salaam were resistant to commonly used antimicrobial agents during the two years of the study. Therefore, there is a great need to control the utilisation of antimicrobial agents in cholera control, in addition to continuing carrying out surveillance of ...

  11. Efficacy of an insecticide paint against insecticide-susceptible and resistant mosquitoes - Part 1: Laboratory evaluation

    Directory of Open Access Journals (Sweden)

    Carnevale Pierre

    2010-11-01

    Full Text Available Abstract Background The main malaria vector Anopheles gambiae and the urban pest nuisance Culex quinquefasciatus are increasingly resistant to pyrethroids in many African countries. There is a need for new products and strategies. Insecticide paint Inesfly 5A IGR™, containing two organophosphates (OPs, chlorpyrifos and diazinon, and insect growth regulator (IGR, pyriproxyfen, was tested under laboratory conditions for 12 months following WHOPES Phase I procedures. Methods Mosquitoes used were laboratory strains of Cx. quinquefasciatus susceptible and resistant to OPs. The paint was applied at two different doses (1 kg/6 m2 and 1 kg/12 m2 on different commonly used surfaces: porous (cement and stucco and non-porous (softwood and hard plastic. Insecticide efficacy was studied in terms of delayed mortality using 30-minute WHO bioassay cones. IGR efficacy on fecundity, fertility and larval development was studied on OP-resistant females exposed for 30 minutes to cement treated and control surfaces. Results After treatment, delayed mortality was high (87-100% even against OP-resistant females on all surfaces except cement treated at 1 kg/12 m2. Remarkably, one year after treatment delayed mortality was 93-100% against OP-resistant females on non-porous surfaces at both doses. On cement, death rates were low 12 months after treatment regardless of the dose and the resistance status. Fecundity, fertility and adult emergence were reduced after treatment even at the lower dose (p -3. A reduction in fecundity was still observed nine months after treatment at both doses (p -3 and adult emergence was reduced at the higher dose (p -3. Conclusions High mortality rates were observed against laboratory strains of the pest mosquito Cx. quinquefasciatus susceptible and resistant to insecticides. Long-term killing remained equally important on non-porous surfaces regardless the resistance status for over 12 months. The paint's effect on fecundity, fertility and

  12. Strain variation in the susceptibility and immune response to Clonorchis sinensis infection in mice.

    Science.gov (United States)

    Uddin, Md Hafiz; Li, Shunyu; Bae, Young Mee; Choi, Min-Ho; Hong, Sung-Tae

    2012-03-01

    Mice have shown various susceptibility to infection by Clonorchis sinensis. To compare the intra-specific variation in the host-parasite relationship of C. sinensis, 6 strains of mice (ICR, BALB/c, C57BL/6, DDY, CBA/N, and C3H/HeN) with 3 different haplotypes were evaluated on their susceptibility. The worm recovery rate and immunological responses were observed after 4 and 8 weeks of infection with 30 metacercariae. The highest worm recovery rate was observed as 20.7% in the C3H/HeN strain after 4 weeks of infection along with histopathological changes. The rate was 10.0% in C57BL/6 mice after 8 weeks. ICR, BALB/c, and CBA/N showed elevated levels of IgE at both time points when compared to the rest of the strains. The serum IgG1 and IgG2a levels were elevated in most of the strains; however, the C57BL/6 strain showed a lower level of IgG2a that indicated the IgG1 predominance over IgG2a. The production of IL-4 after concanavalin-A stimulation of splenocytes slightly increased among the mouse strains except C3H/HeN after 4 or 8 weeks of infection, but each strain produced high levels of IFN-γ after 8 weeks, which implied mixed Th1/Th2 responses. ICR, DDY, CBA/N, and C3H/HeN strains showed a significantly increased level of IL-10 after 8 weeks as compared to C57BL/6. All of the strains showed an increased level of IL-13 and suggested fibrotic changes in the mice. In conclusion, mice are insusceptible to infection with C. sinensis; however, the C57BL/6, BALB/c and ICR strains are relatively susceptible after 8 weeks of infection among the six strains. Worm expulsion may be one of the causes of low susceptibility of C3H/HeN mice strain at the 8th week. Elevated IgE, IFN-γ, and IL-13 of infected mice suggest both Th1 and Th2 responses that may be related to the low host susceptibility. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  13. In vitro susceptibility of Trypanosoma cruzi strains from Santander, Colombia, to hexadecylphosphocholine (miltefosine), nifurtimox and benznidazole.

    Science.gov (United States)

    Luna, Katherine Paola; Hernández, Indira Paola; Rueda, César Mauricio; Zorro, María Magdalena; Croft, Simon L; Escobar, Patricia

    2009-09-01

    The current chemotherapy for Chagas disease is unsatisfactory with only two drugs available for treatment. Research to discover new drugs for Chagas disease is urgent. Hexadecyl-phosphocholine (HPC, miltefosine) has been demonstrated to have in vitro activity against Trypanosoma cruzi parasites, but its activity on different Colombian T. cruzi strains is not known. To evaluate the in vitro susceptibility of T. cruzi strains isolated from humans and vectors in Santander, Colombia. to miltefosine, nifurtimox and benznidazole. Eight T. cruzi Colombian strains and three reference strains (Esmeraldo, SilvioX10 and Y) were studied. Drug activities against extracellular epimastigotes and intracellular amastigotes were determined by microscopic counting. The results were expressed as the concentrations that inhibited 50% and 90% growth (IC50 and IC90). For miltefosine a similar range of drug activity was observed against all the Colombian strains, all parasites being more susceptible to miltefosine than to the reference drugs. The intracellular amastigotes were more susceptible to miltefosine (IC50 0.08 to 0.63 microM and IC90 0.21 to 2.21 microM) than extracellular forms (IC50 nifurtimox than to benznidazole and some differences in activity of benznidazole between T. cruzi strains was observed. The results showed the significant in vitro activity of miltefosine against T. cruzi stages, and the expected results for the reference drugs. Further in vivo studies with miltefosine are planned.

  14. Study of strains of Candida spp. Isolated from catheters in UHC of Oran (Algeria): Identification and antifungal susceptibility.

    Science.gov (United States)

    Bendjelloul, M; Boucherit-Otmani, Z; Boucherit, K

    2016-09-01

    The increasing incidence of Candida spp., and the vital prognosis often compromise for patients with Candida species make urgent the exact knowledge of their distribution worldwide and exhaust action antifungals currently used in clinical. That why we carry out an epidemiological study of Candida species and testing their susceptibility against two antifungals: amphotericin B and caspofungin. Samplings of peripheral venous catheters (PVC) were carried out from during 8months on the services of Internal medicine, Surgery A and Neonatology of Oran's University Hospital Center (UHC). The study of the susceptibility of Candida species to antifungal agents was performed according to the Clinical Laboratory Standards Institute (CLSI 2008). From 300 samples, 25 yeasts were isolated. The rate of colonization PVC was 8.33% by Candida spp. The most isolated strains were Candida parapsilosis with 64% of cases, followed by Candida albicans (12%) then 8% for Candida glabrata and Candida krusei. However, only 4% of isolates were Candida famata or Candida lusitaniae. Furthermore all isolated strains were susceptible to amphotericin B with Minimum Inhibitory Concentrations (MIC) ranging from 0.25 to 1μg/mL. MIC obtained with caspofungin vary from 0.0625 to 2μg/mL for all strains. Moreover, one strain of C. krusei is resistant to caspofungin with a MIC superior to 8μg/mL. All though caspofungin is at least as effective as amphotericin B, it is better tolerated for the treatment of invasive fungal infections. Copyright © 2016. Published by Elsevier Masson SAS.

  15. Antimicrobial susceptibility of Brazilian Clostridium difficile strains determined by agar dilution and disk diffusion

    Directory of Open Access Journals (Sweden)

    Edmir Geraldo Fraga

    2016-09-01

    Full Text Available Clostridium difficile is a leading cause of diarrhea in hospitalized patients worldwide. While metronidazole and vancomycin are the most prescribed antibiotics for the treatment of this infection, teicoplanin, tigecycline and nitazoxanide are alternatives drugs. Knowledge on the antibiotic susceptibility profiles is a basic step to differentiate recurrence from treatment failure due to antimicrobial resistance. Because C. difficile antimicrobial susceptibility is largely unknown in Brazil, we aimed to determine the profile of C. difficile strains cultivated from stool samples of inpatients with diarrhea and a positive toxin A/B test using both agar dilution and disk diffusion methods. All 50 strains tested were sensitive to metronidazole according to CLSI and EUCAST breakpoints with an MIC90 value of 2 μg/mL. Nitazoxanide and tigecycline were highly active in vitro against these strains with an MIC90 value of 0.125 μg/mL for both antimicrobials. The MIC90 were 4 μg/mL and 2 μg/mL for vancomycin and teicoplanin, respectively. A resistance rate of 8% was observed for moxifloxacin. Disk diffusion can be used as an alternative to screen for moxifloxacin resistance, nitazoxanide, tigecycline and metronidazole susceptibility, but it cannot be used for testing glycopeptides. Our results suggest that C. difficile strains from São Paulo city, Brazil, are susceptible to metronidazole and have low MIC90 values for most of the current therapeutic options available in Brazil.

  16. Antimicrobial susceptibility testing of 230 Helicobacter pylori strains: importance of medium, inoculum, and incubation time

    DEFF Research Database (Denmark)

    Hartzen, S H; Andersen, L P; Bremmelgaard, A

    1997-01-01

    No standardized method of susceptibility testing for Helicobacter pylori is currently available, so before a large agar dilution study comprising 230 H. pylori strains belonging to more than 80 genetically different groups was initiated, we performed a relatively small preliminary study to determ...

  17. Antimicrobial susceptibility of Brazilian Clostridium difficile strains determined by agar dilution and disk diffusion

    Directory of Open Access Journals (Sweden)

    Edmir Geraldo Fraga

    Full Text Available Abstract Clostridium difficile is a leading cause of diarrhea in hospitalized patients worldwide. While metronidazole and vancomycin are the most prescribed antibiotics for the treatment of this infection, teicoplanin, tigecycline and nitazoxanide are alternatives drugs. Knowledge on the antibiotic susceptibility profiles is a basic step to differentiate recurrence from treatment failure due to antimicrobial resistance. Because C. difficile antimicrobial susceptibility is largely unknown in Brazil, we aimed to determine the profile of C. difficile strains cultivated from stool samples of inpatients with diarrhea and a positive toxin A/B test using both agar dilution and disk diffusion methods. All 50 strains tested were sensitive to metronidazole according to CLSI and EUCAST breakpoints with an MIC90 value of 2 μg/mL. Nitazoxanide and tigecycline were highly active in vitro against these strains with an MIC90 value of 0.125 μg/mL for both antimicrobials. The MIC90 were 4 μg/mL and 2 μg/mL for vancomycin and teicoplanin, respectively. A resistance rate of 8% was observed for moxifloxacin. Disk diffusion can be used as an alternative to screen for moxifloxacin resistance, nitazoxanide, tigecycline and metronidazole susceptibility, but it cannot be used for testing glycopeptides. Our results suggest that C. difficile strains from São Paulo city, Brazil, are susceptible to metronidazole and have low MIC90 values for most of the current therapeutic options available in Brazil.

  18. Genome diversity of Pseudomonas aeruginosa PAO1 laboratory strains.

    Science.gov (United States)

    Klockgether, Jens; Munder, Antje; Neugebauer, Jens; Davenport, Colin F; Stanke, Frauke; Larbig, Karen D; Heeb, Stephan; Schöck, Ulrike; Pohl, Thomas M; Wiehlmann, Lutz; Tümmler, Burkhard

    2010-02-01

    Pseudomonas aeruginosa PAO1 is the most commonly used strain for research on this ubiquitous and metabolically versatile opportunistic pathogen. Strain PAO1, a derivative of the original Australian PAO isolate, has been distributed worldwide to laboratories and strain collections. Over decades discordant phenotypes of PAO1 sublines have emerged. Taking the existing PAO1-UW genome sequence (named after the University of Washington, which led the sequencing project) as a blueprint, the genome sequences of reference strains MPAO1 and PAO1-DSM (stored at the German Collection for Microorganisms and Cell Cultures [DSMZ]) were resolved by physical mapping and deep short read sequencing-by-synthesis. MPAO1 has been the source of near-saturation libraries of transposon insertion mutants, and PAO1-DSM is identical in its SpeI-DpnI restriction map with the original isolate. The major genomic differences of MPAO1 and PAO1-DSM in comparison to PAO1-UW are the lack of a large inversion, a duplication of a mobile 12-kb prophage region carrying a distinct integrase and protein phosphatases or kinases, deletions of 3 to 1,006 bp in size, and at least 39 single-nucleotide substitutions, 17 of which affect protein sequences. The PAO1 sublines differed in their ability to cope with nutrient limitation and their virulence in an acute murine airway infection model. Subline PAO1-DSM outnumbered the two other sublines in late stationary growth phase. In conclusion, P. aeruginosa PAO1 shows an ongoing microevolution of genotype and phenotype that jeopardizes the reproducibility of research. High-throughput genome resequencing will resolve more cases and could become a proper quality control for strain collections.

  19. Comprehensive study of proteasome inhibitors against Plasmodium falciparum laboratory strains and field isolates from Gabon

    Directory of Open Access Journals (Sweden)

    Kremsner Peter G

    2008-09-01

    Full Text Available Abstract Background The emergence and spread of Plasmodium falciparum resistance to almost all available antimalarial drugs necessitates the search for new chemotherapeutic compounds. The ubiquitin/proteasome system plays a major role in overall protein turnover, especially in fast dividing eukaryotic cells including plasmodia. Previous studies show that the 20S proteasome is expressed and catalytically active in plasmodia and treatment with proteasome inhibitors arrests parasite growth. This is the first comprehensive screening of proteasome inhibitors with different chemical modes of action against laboratory strains of P. falciparum. Subsequently, a selection of inhibitors was tested in field isolates from Lambaréné, Gabon. Methods Epoxomicin, YU101, YU102, MG132, MG115, Z-L3-VS, Ada-Ahx3-L3-VS, lactacystin, bortezomib (Velcade®, gliotoxin, PR11 and PR39 were tested and compared to chloroquine- and artesunate-activities in a standardized in vitro drug susceptibility assay against P. falciparum laboratory strains 3D7, D10 and Dd2. Freshly obtained field isolates from Lambaréné, Gabon, were used to measure the activity of chloroquine, artesunate, epoxomicin, MG132, lactacystin and bortezomib. Parasite growth was detected through histidine-rich protein 2 (HRP2 production. Raw data were fitted by a four-parameter logistic model and individual inhibitory concentrations (50%, 90%, and 99% were calculated. Results Amongst all proteasome inhibitors tested, epoxomicin showed the highest activity in chloroquine-susceptible (IC50: 6.8 nM [3D7], 1.7 nM [D10] and in chloroquine-resistant laboratory strains (IC50: 10.4 nM [Dd2] as well as in field isolates (IC50: 8.5 nM. The comparator drug artesunate was even more active (IC50: 1.0 nM, whereas all strains were chloroquine-resistant (IC50: 113 nM. Conclusion The peptide α',β'-epoxyketone epoxomicin is highly active against P. falciparum regardless the grade of the parasite's chloroquine

  20. Efficacy of an insecticide paint against insecticide-susceptible and resistant mosquitoes - Part 1: Laboratory evaluation

    Science.gov (United States)

    2010-01-01

    Background The main malaria vector Anopheles gambiae and the urban pest nuisance Culex quinquefasciatus are increasingly resistant to pyrethroids in many African countries. There is a need for new products and strategies. Insecticide paint Inesfly 5A IGR™, containing two organophosphates (OPs), chlorpyrifos and diazinon, and insect growth regulator (IGR), pyriproxyfen, was tested under laboratory conditions for 12 months following WHOPES Phase I procedures. Methods Mosquitoes used were laboratory strains of Cx. quinquefasciatus susceptible and resistant to OPs. The paint was applied at two different doses (1 kg/6 m2 and 1 kg/12 m2) on different commonly used surfaces: porous (cement and stucco) and non-porous (softwood and hard plastic). Insecticide efficacy was studied in terms of delayed mortality using 30-minute WHO bioassay cones. IGR efficacy on fecundity, fertility and larval development was studied on OP-resistant females exposed for 30 minutes to cement treated and control surfaces. Results After treatment, delayed mortality was high (87-100%) even against OP-resistant females on all surfaces except cement treated at 1 kg/12 m2. Remarkably, one year after treatment delayed mortality was 93-100% against OP-resistant females on non-porous surfaces at both doses. On cement, death rates were low 12 months after treatment regardless of the dose and the resistance status. Fecundity, fertility and adult emergence were reduced after treatment even at the lower dose (p paint's effect on fecundity, fertility and adult emergence may continue to provide an additional angle of attack in reducing overall population densities when the lethal effect of OPs diminishes over time. Some options on how to deal with porous materials are given. Implications in vector control are discussed. PMID:21108819

  1. Antifungal Susceptibility Profiles of 1698 Yeast Reference Strains Revealing Potential Emerging Human Pathogens

    Science.gov (United States)

    Desnos-Ollivier, Marie; Robert, Vincent; Raoux-Barbot, Dorothée; Groenewald, Marizeth; Dromer, Françoise

    2012-01-01

    New molecular identification techniques and the increased number of patients with various immune defects or underlying conditions lead to the emergence and/or the description of novel species of human and animal fungal opportunistic pathogens. Antifungal susceptibility provides important information for ecological, epidemiological and therapeutic issues. The aim of this study was to assess the potential risk of the various species based on their antifungal drug resistance, keeping in mind the methodological limitations. Antifungal susceptibility profiles to the five classes of antifungal drugs (polyens, azoles, echinocandins, allylamines and antimetabolites) were determined for 1698 yeast reference strains belonging to 992 species (634 Ascomycetes and 358 Basidiomycetes). Interestingly, geometric mean minimum inhibitory concentrations (MICs) of all antifungal drugs tested were significantly higher for Basidiomycetes compared to Ascomycetes (p<0.001). Twenty four strains belonging to 23 species of which 19 were Basidiomycetes seem to be intrinsically “resistant” to all drugs. Comparison of the antifungal susceptibility profiles of the 4240 clinical isolates and the 315 reference strains belonging to 53 shared species showed similar results. Even in the absence of demonstrated in vitro/in vivo correlation, knowing the in vitro susceptibility to systemic antifungal agents and the putative intrinsic resistance of yeast species present in the environment is important because they could become opportunistic pathogens. PMID:22396754

  2. Antifungal susceptibility profiles of 1698 yeast reference strains revealing potential emerging human pathogens.

    Directory of Open Access Journals (Sweden)

    Marie Desnos-Ollivier

    Full Text Available New molecular identification techniques and the increased number of patients with various immune defects or underlying conditions lead to the emergence and/or the description of novel species of human and animal fungal opportunistic pathogens. Antifungal susceptibility provides important information for ecological, epidemiological and therapeutic issues. The aim of this study was to assess the potential risk of the various species based on their antifungal drug resistance, keeping in mind the methodological limitations. Antifungal susceptibility profiles to the five classes of antifungal drugs (polyens, azoles, echinocandins, allylamines and antimetabolites were determined for 1698 yeast reference strains belonging to 992 species (634 Ascomycetes and 358 Basidiomycetes. Interestingly, geometric mean minimum inhibitory concentrations (MICs of all antifungal drugs tested were significantly higher for Basidiomycetes compared to Ascomycetes (p<0.001. Twenty four strains belonging to 23 species of which 19 were Basidiomycetes seem to be intrinsically "resistant" to all drugs. Comparison of the antifungal susceptibility profiles of the 4240 clinical isolates and the 315 reference strains belonging to 53 shared species showed similar results. Even in the absence of demonstrated in vitro/in vivo correlation, knowing the in vitro susceptibility to systemic antifungal agents and the putative intrinsic resistance of yeast species present in the environment is important because they could become opportunistic pathogens.

  3. Strain, Sex, and Open-Field Behavior: Factors Underlying the Genetic Susceptibility to Helplessness

    Science.gov (United States)

    Padilla, Eimeira; Barrett, Douglas W.; Shumake, Jason D.; Gonzalez-Lima, F.

    2009-01-01

    Learned helplessness represents a failure to escape after exposure to inescapable stress and may model human psychiatric disorders related to stress. Previous work has demonstrated individual differences in susceptibility to learned helplessness. In this study, we assessed different factors associated with this susceptibility, including strain, sex, and open-field behavior. Testing of three rat strains (Holtzman, Long-Evans, and Sprague-Dawley) revealed that Holtzman rats were the most susceptible to helplessness. Holtzman rats not only had the longest escape latencies following inescapable shock, but also showed spontaneous escape deficits in the absence of prior shock when tested with a fixed-ratio 2 (FR2) running response. Moreover, when tested with fixed-ratio 1 (FR1) running—an easy response normally unaffected by helplessness training in rats—inescapable shock significantly increased the escape latencies of Holtzman rats. Within the Holtzman strain, we confirmed recent findings that females showed superior escape performance and therefore appeared more resistant to helplessness than males. However, regression and covariance analyses suggest that this sex difference may be explained by more baseline ambulatory activity among females. In addition, some indices of novelty reactivity (greater exploration of novel vs. familiar open-field) predicted subsequent helpless behavior. In conclusion, Holtzman rats, and especially male Holtzman rats, have a strong predisposition to become immobile when stressed which interferes with their ability to learn active escape responses. The Holtzman strain therefore appears to be a commercially available model for studying susceptibility to helplessness in males, and novelty-seeking may be a marker of this susceptibility. PMID:19428642

  4. Spontaneous Staphylococcus xylosus Infection in Mice Deficient in NADPH Oxidase and Comparison with Other Laboratory Mouse Strains

    Science.gov (United States)

    Gozalo, Alfonso S; Hoffmann, Victoria J; Brinster, Lauren R; Elkins, William R; Ding, Li; Holland, Steven M

    2010-01-01

    Staphylococcus xylosus typically is described as a nonpathogenic common inhabitant of rodent skin. Reports of S. xylosus as a primary pathogen in human and veterinary medicine are scarce. Here we report 37 cases, affecting 12 strains of laboratory mice, of spontaneous infections in which S. xylosus was isolated and considered to be the primary pathogen contributing to the death or need for euthanasia of the animal. Infection with S. xylosus was the major cause of death or euthanasia in 3 strains of mice deficient in the production of phagocyte superoxide due to defects in NADPH oxidase. NADPH-oxidase–deficient mice (n = 21) were most susceptible to spontaneous S. xylosus infections. The infections were characterized by abscesses and granulomas in soft tissues, with bacterial migration to internal organs (primarily regional lymph nodes and lungs and, to a lesser degree, muscle, bone, and meninges). In contrast, 9 strains of phagocyte-superoxide–producing mice (n = 16) also had S. xylosus infections, but these were largely confined to eyelids, ocular conjunctiva, and skin and rarely involved other tissues or organs. Because exhaustive bacterial culture and isolation may not be performed routinely from mouse abscesses, S. xylosus infections may be underdiagnosed. S. xylosus should be considered in the differential diagnosis in laboratory mice with abscesses and other skin lesions. This report expands the range of mouse strains and tissues and organs susceptible to spontaneous S. xylosus infection and compares the pathology among various mice strains. PMID:20819397

  5. Efficient recovery of fluoroquinolone-susceptible and fluoroquinolone-resistant Escherichia coli strains from frozen samples.

    Science.gov (United States)

    Lautenbach, Ebbing; Santana, Evelyn; Lee, Abby; Tolomeo, Pam; Black, Nicole; Babson, Andrew; Perencevich, Eli N; Harris, Anthony D; Smith, Catherine A; Maslow, Joel

    2008-04-01

    We assessed the rate of recovery of fluoroquinolone-resistant and fluoroquinolone-susceptible Escherichia coli isolates from culture of frozen perirectal swab samples compared with the results for culture of the same specimen before freezing. Recovery rates for these 2 classes of E. coli were 91% and 83%, respectively. The majority of distinct strains recovered from the initial sample were also recovered from the frozen sample. The strains that were not recovered were typically present only in low numbers in the initial sample. These findings emphasize the utility of frozen surveillance samples.

  6. Development of Diagnostic Insecticide Concentrations and Assessment of Insecticide Susceptibility in German Cockroach (Dictyoptera: Blattellidae) Field Strains Collected From Public Housing.

    Science.gov (United States)

    Fardisi, Mahsa; Gondhalekar, Ameya D; Scharf, Michael E

    2017-06-01

    Insecticide resistance in German cockroaches (Blattella germanica (L.)) has been a barrier to effective control since its first documentation in the 1950s. A necessary first step toward managing resistance is to understand insecticide susceptibility profiles in field-collected strains so that active ingredients (AIs) with lowest resistance levels can be identified. As a first step in this study, diagnostic concentrations (DCs) were determined for 14 insecticide AIs based on lethal concentrations that killed 99% or 90% of the individuals from a susceptible lab strain (JWax-S). Next, cockroaches were collected from two low-income multifamily housing complexes in Danville, IL, and Indianapolis, IN, and used to establish laboratory strains. These strains were screened against the 14 AI-DCs in vial bioassays, and susceptibility profiles were determined by comparing percent mortalities between the field strains relative to the JWax-S strain. Results revealed lowest resistance of field strains to boric acid, abamectin, dinotefuran, clothianidin, thiamethoxam, and chlorfenapyr. For the AIs hydramethylnon and imidacloprid, field strains did not display survivorship different than the lab strain, but >90% mortality was never achieved. Lastly, both field strains displayed resistance to indoxacarb, fipronil, acetamiprid, beta-cyfluthrin, bifenthrin, and lambda-cyhalothrin, but at varying levels. These results satisfy two objectives. First, baseline monitoring DCs were established for 14 insecticides presently registered for use against cockroaches, which represents a useful resource. Second, our findings reveal insecticide AIs with lowest resistance levels for use in forthcoming field studies that will investigate impacts of different insecticide deployment strategies on resistance management and evolution in cockroach field populations. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

  7. Development of Diagnostic Insecticide Concentrations and Assessment of Insecticide Susceptibility in German Cockroach (Dictyoptera: Blattellidae) Field Strains Collected From Public Housing

    Science.gov (United States)

    Fardisi, Mahsa; Gondhalekar, Ameya D.

    2017-01-01

    Abstract Insecticide resistance in German cockroaches (Blattella germanica (L.)) has been a barrier to effective control since its first documentation in the 1950s. A necessary first step toward managing resistance is to understand insecticide susceptibility profiles in field-collected strains so that active ingredients (AIs) with lowest resistance levels can be identified. As a first step in this study, diagnostic concentrations (DCs) were determined for 14 insecticide AIs based on lethal concentrations that killed 99% or 90% of the individuals from a susceptible lab strain (JWax-S). Next, cockroaches were collected from two low-income multifamily housing complexes in Danville, IL, and Indianapolis, IN, and used to establish laboratory strains. These strains were screened against the 14 AI-DCs in vial bioassays, and susceptibility profiles were determined by comparing percent mortalities between the field strains relative to the JWax-S strain. Results revealed lowest resistance of field strains to boric acid, abamectin, dinotefuran, clothianidin, thiamethoxam, and chlorfenapyr. For the AIs hydramethylnon and imidacloprid, field strains did not display survivorship different than the lab strain, but >90% mortality was never achieved. Lastly, both field strains displayed resistance to indoxacarb, fipronil, acetamiprid, beta-cyfluthrin, bifenthrin, and lambda-cyhalothrin, but at varying levels. These results satisfy two objectives. First, baseline monitoring DCs were established for 14 insecticides presently registered for use against cockroaches, which represents a useful resource. Second, our findings reveal insecticide AIs with lowest resistance levels for use in forthcoming field studies that will investigate impacts of different insecticide deployment strategies on resistance management and evolution in cockroach field populations. PMID:28334270

  8. Susceptibility of clinical isolates of Bacteroides fragilis group strains to cefoxitin, cefoperazone and ticarcillin/clavulanate

    Directory of Open Access Journals (Sweden)

    PEIXOTO JÚNIOR Arnaldo Aires

    2000-01-01

    Full Text Available A total of 40 strains of the B. fragilis group was isolated from clinical specimens in two hospital centers in Fortaleza from 1993 to 1997. The most frequently isolated species was Bacteroides fragilis (19 strains and most isolates came from intra-abdominal and wound infections. The susceptibility profile was traced for cefoxitin, cefoperazone and ticarcillin-clavulanate by using the agar dilution reference method. All isolates were susceptible to ticarcillin-clavulanate (128/2mug/ml. Resistance rates of 15 and 70% were detected to cefoxitin (64mug/ml and cefoperazone (64mug/ml, respectively. Such regional results permit a better orientation in choosing this group of antibiotics for prophylaxis and therapy especially in relation to cefoxitin, which is frequently used in the hospital centers studied.

  9. Analysis of a p53 Mutation Associated with Cancer Susceptibility for Biochemistry and Genetic Laboratory Courses

    Science.gov (United States)

    Soto-Cruz, Isabel; Legorreta-Herrera, Martha

    2009-01-01

    We have devised and implemented a module for an upper division undergraduate laboratory based on the amplification and analysis of a p53 polymorphism associated with cancer susceptibility. First, students collected a drop of peripheral blood cells using a sterile sting and then used FTA cards to extract the genomic DNA. The p53 region is then PCR…

  10. Antibiotic susceptibility profiles of Mycoplasma synoviae strains originating from Central and Eastern Europe

    OpenAIRE

    Kreizinger, Zsuzsa; Grózner, Dénes; Sulyok, Kinga M.; Nilsson, Kristin; Hrivnák, Veronika; Benčina, Dušan; Gyuranecz, Miklós

    2017-01-01

    Background Mycoplasma synoviae causes infectious synovitis and respiratory diseases in chickens and turkeys and may lead to egg shell apex abnormalities in chickens; hence possesses high economic impact on the poultry industry. Control of the disease consists of eradication, vaccination or medication. The aim of the present study was to determine the in vitro susceptibility to 14 different antibiotics and an antibiotic combination of M. synoviae strains originating from Hungary and other coun...

  11. Antimicrobial susceptibility of Brazilian Clostridium difficile strains determined by agar dilution and disk diffusion.

    Science.gov (United States)

    Fraga, Edmir Geraldo; Nicodemo, Antonio Carlos; Sampaio, Jorge Luiz Mello

    2016-01-01

    Clostridium difficile is a leading cause of diarrhea in hospitalized patients worldwide. While metronidazole and vancomycin are the most prescribed antibiotics for the treatment of this infection, teicoplanin, tigecycline and nitazoxanide are alternatives drugs. Knowledge on the antibiotic susceptibility profiles is a basic step to differentiate recurrence from treatment failure due to antimicrobial resistance. Because C. difficile antimicrobial susceptibility is largely unknown in Brazil, we aimed to determine the profile of C. difficile strains cultivated from stool samples of inpatients with diarrhea and a positive toxin A/B test using both agar dilution and disk diffusion methods. All 50 strains tested were sensitive to metronidazole according to CLSI and EUCAST breakpoints with an MIC90 value of 2μg/mL. Nitazoxanide and tigecycline were highly active in vitro against these strains with an MIC90 value of 0.125μg/mL for both antimicrobials. The MIC90 were 4μg/mL and 2μg/mL for vancomycin and teicoplanin, respectively. A resistance rate of 8% was observed for moxifloxacin. Disk diffusion can be used as an alternative to screen for moxifloxacin resistance, nitazoxanide, tigecycline and metronidazole susceptibility, but it cannot be used for testing glycopeptides. Our results suggest that C. difficile strains from São Paulo city, Brazil, are susceptible to metronidazole and have low MIC90 values for most of the current therapeutic options available in Brazil. Copyright © 2016 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. All rights reserved.

  12. Antibiotic susceptibility profiles of Mycoplasma sp. 1220 strains isolated from geese in Hungary

    OpenAIRE

    Gr?zner, D?nes; Kreizinger, Zsuzsa; Sulyok, Kinga M.; R?nai, Zsuzsanna; Hrivn?k, Veronika; Turcs?nyi, Ibolya; J?nosi, Szil?rd; Gyuranecz, Mikl?s

    2016-01-01

    Background Mycoplasma sp. 1220 can induce inflammation primarily in the genital and respiratory tracts of waterfowl, leading to serious economic losses. Adequate housing and appropriate antibiotic treatment are promoted in the control of the disease. The aim of the present study was to determine the in vitro susceptibility to thirteen different antibiotics and an antibiotic combination of thirty-eight M. sp. 1220 strains isolated from geese and a duck in several parts of Hungary, Central Euro...

  13. Species Identification, Strain Differentiation, and Antifungal Susceptibility of Dermatophyte Species Isolated From Clinically Infected Arabian Horses

    DEFF Research Database (Denmark)

    El Damaty, Hend M; Tartor, Yasmine H; Mahmmod, Yasser Saadeldien Ibrahim

    2017-01-01

    Arabian horses, the eldest equine breeds, have great economic and social significance for its long, unique, and storied history. Molecular characterization of dermatophyte species affecting Arabian horses is a crucial necessity for epidemiologic and therapeutic purposes. The objective of this study...... was to identify and differentiate isolates of dermatophytes isolated from naturally infected Arabian horses at species and strains levels using PCR-restriction fragment length polymorphism (RFLP) and DNA sequencing. Additionally, antifungal susceptibility testing using broth microdilution method was performed...

  14. Antibiotic susceptibility, antibacterial activity and characterisation of Enterococcus faecium strains isolated from breast milk

    Science.gov (United States)

    Kıvanç, Sertaç Argun; Kıvanç, Merih; Yiğit, Tülay

    2016-01-01

    Enterococci, which have useful biotechnological applications, produce bacteriocins, including those that exert anti-Listerial activity. The present study aimed to determine the antibiotic susceptibility patterns and antimicrobial activity of Enterococcus faecium strains isolated from human breast milk. The strains were identified using carbohydrate fermentation tests and ribotyping. Subsequently, the antibacterial activity of the isolates was investigated, and the quantities of lactic acid and hydrogen peroxide produced, and the proteolytic activity of E. faecium, were determined. In addition, biofilm formation by E. faecium strains was assessed. E. faecium strains exhibited antimicrobial activity against food-borne and clinical bacterial isolates. Furthermore, following 24 h incubation, the tested strains exhibited resistance to a pH range of 2.0–9.5 and tolerance of bile acid, lysozyme activity and phenol. Supernatants of the E. faecium TM13, TM15, TM17 and TM18 strains were shown to be effective against Listeria monocytogenes, and were also resistant to heat. Further studies are required in order to determine whether certain strains of E. faecium may be used for the development of novel antibacterial agents. PMID:27602088

  15. Antimosquito property of Petroselinum crispum (Umbellifereae) against the pyrethroid resistant and susceptible strains of Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Intirach, J; Junkum, A; Lumjuan, N; Chaithong, U; Jitpakdi, A; Riyong, D; Wannasan, A; Champakaew, D; Muangmoon, R; Chansang, A; Pitasawat, B

    2016-12-01

    The increasing and widespread resistance to conventional synthetic insecticides in vector populations has underscored the urgent need to establish alternatives in the mosquito management system. This study was carried out with the aim to investigate the antimosquito property, larvicidal and adulticidal potential, of plant products against both the pyrethroid-susceptible and resistant strains of Aedes aegypti. Seventeen plant products, including essential oils and ethanolic extracts, were obtained by steam distillation and extraction with 95 % ethanol, respectively. Their larvicidal activity was screened, using World Health Organization (WHO) procedures against A. aegypti, Muang Chiang Mai-susceptible (MCM-S) strain. The most effective product was a candidate for investigating larvicidal and adulticidal potential against three laboratory strains of A. aegypti, comprising MCM-S, Pang Mai Dang-resistant (PMD-R), and Upakut-resistant (UPK-R). Potential toxicity of the plant candidate was compared with that of synthetic temephos, permethrin, and deltamethrin. Chemical constituents of the most effective plant product also were analyzed by gas chromatography-mass spectrometry (GC-MS). Results obtained from the preliminary screening revealed the varying larvicidal efficacy of plant-derived products against MCM-S A. aegypti, with mortality ranging from 0 to 100 %. The larvicidal activity of seven effective plant products was found to be dose dependent, with the highest efficacy established from Petroselinum crispum fruit oil, followed by oils of Foeniculum vulgare, Myristica fragrans, Limnophila aromatica, Piper sarmentosum, Curcuma longa, and M. fragrans ethanolic extract (LC50 values of 43.22, 44.84, 47.42, 47.94, 49.19, 65.51, and 75.45 ppm, respectively). Essential oil of P. crispum was then investigated further and proved to be a promising larvicide and adulticide against all strains of A. aegypti. The pyrethroid-resistant strains of both PMD-R and UPK-R A. aegypti

  16. Variability of laboratory identification and antibiotic susceptibility reporting of Pseudomonas spp. isolates from dogs with chronic otitis externa.

    Science.gov (United States)

    Schick, Anthea E; Angus, John C; Coyner, Kimberly S

    2007-04-01

    The purpose of this study was to evaluate interlaboratory variation in isolation and antibiotic susceptibility pattern of Pseudomonas spp. as reported to veterinarians for cases of canine chronic bacterial otitis externa. Twenty-six dogs with unilateral or bilateral bacterial otitis externa from multiple referral practices were included in this prospective study. Triplicate samples collected simultaneously from the same location in the external ear canal were randomly submitted to three laboratories for culture and susceptibility testing. Pseudomonas spp. were isolated from 18 of 34 (53%) ears. All three laboratories agreed on the presence of Pseudomonas spp. in 15 (83.3%) ears sampled. However, two laboratories agreed on two (11.1%) occasions, and on one occasion (5.5%) Pseudomonas spp. were identified in only one laboratory. Minimum inhibitory concentration (MIC) susceptibilities to 11 antibiotics were compared between laboratories B and C. Using laboratory-defined susceptibility of sensitive (S), intermediate (I) and resistant (R), none of the 16 Pseudomonas spp. with MIC data reported had identical patterns of antibiotic susceptibility. Agreement in susceptibility to individual antibiotics was observed in 13 of 16 (81%) occasions for amikacin and gentamicin, 10 of 16 (63%) occasions for ticarcillin, and nine of 16 (56%) for enrofloxacin. These results indicate that Pseudomonas spp. were identified by all three laboratories chosen for this study in 83% of the time. Moreover, antibiotic susceptibility patterns and MIC values reported to veterinarians may not agree between laboratories. Veterinarians should interpret bacterial culture and susceptibility results with multiple caveats including variability between laboratories.

  17. Variation in susceptibility to benznidazole in isolates derived from Trypanosoma cruzi parental strains

    Directory of Open Access Journals (Sweden)

    Veloso VM

    2001-01-01

    Full Text Available In this work, the susceptibility to benznidazole of two parental Trypanosoma cruzi strains, Colombian and Berenice-78, was compared to isolates obtained from dogs infected with these strains for several years. In order to evaluate the susceptibility to benznidazole two groups of mice were infected with one of five distinct populations isolated from dogs as well as the two parental strains of T. cruzi. The first group was treated with benznidazole during the acute phase and the second remained untreated controls. The animals were considered cured when parasitological and serological tests remained persistently negative. Mice infected with the Colombian strain and its isolates Colombian (A and B did not cure after treatment. On the other hand, all animals infected with Berenice-78 were cured by benznidazole treatment. However, 100%, 50% and 70% of cure rates were observed in animals infected with the isolates Berenice-78 B, C and D, respectively. No significant differences were observed in serological profile of infected control groups, with all animals presenting high antibody levels. However, the ELISA test showed differences in serological patterns between mice inoculated with the different T. cruzi isolates and treated with benznidazole. This variability was dependent on the T. cruzi population used and seemed to be associated with the level of resistance to benznidazole.

  18. Antimicrobial susceptibility of Riemerella anatipestifer strains isolated from geese and ducks in Hungary.

    Science.gov (United States)

    Gyuris, Éva; Wehmann, Enikő; Czeibert, Katalin; Magyar, Tibor

    2017-06-01

    Riemerella anatipestifer causes anatipestifer disease in many avian species. A total of 185 R. anatipestifer strains isolated in Hungary between 2000 and 2014 from geese and ducks were tested against 13 antibiotics (ampicillin, doxycycline, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, penicillin, spectinomycin, streptomycin, sulphamethoxazole-trimethoprim, sulphonamide compounds, and tetracycline) by the Kirby-Bauer disk diffusion method. The majority of the strains were susceptible to florfenicol (97.9%), ampicillin (95.1%), penicillin (93%), sulphamethoxazole-trimethoprim (92.4%), and spectinomycin (86.5%). The highest resistance rates were observed for flumequine, tetracycline, erythromycin and streptomycin (94%, 91.4%, 75.1% and 71.4% resistance, respectively). The resistance patterns showed some variation depending on the geographical origin of the strains. The average rate of extensive drug resistance was 30.3%, and its proportion tended to increase in the period examined.

  19. High rate of non-susceptibility to metronidazole and clindamycin in anaerobic isolates: Data from a clinical laboratory from Karachi, Pakistan.

    Science.gov (United States)

    Sheikh, Sadia Omer; Jabeen, Kauser; Qaiser, Saba; Ahsan, Syed Tanwir; Khan, Erum; Zafar, Afia

    2015-06-01

    Due to increasing resistance amongst anaerobic pathogens periodic surveillance of resistance has been recommended in regional/local settings. Anaerobic antimicrobial susceptibility testing is not routinely performed in many laboratories in Pakistan, hence absence of local data may lead to inappropriate empirical therapy in serious cases. 121 clinically significant anaerobic strains (26/121; 21% bacteremic isolates) were isolated and saved from 2010 to 2011. Susceptibility testing against metronidazole, clindamycin, co-amoxiclav, meropenem, piperacillin/tazobactam, linezolid and gatifloxacin was performed by determining minimum inhibitory concentrations (MICs). A high proportion of non-susceptible strains to metronidazole (10% of 121 isolates) and clindamycin (12% of 121 isolates) was seen, most noticeable in Bacteroides fragilis. Three Bacteroides species strains were non-susceptible to both metronidazole and clindamycin. One strain of Clostridium species was fully resistant to metronidazole and had intermediate resistance to clindamycin. No resistance to any of the other tested antibiotics was seen. Resistance to metronidazole was higher in bacteremic vs. non bacteremic isolates (p = value 0.07). In our setting where there is a high usage of empirical metronidazole and clindamycin for the treatment of serious anaerobic infections clinicians should be aware of increased resistance to these agents. Periodic surveillance of resistance to anti-anaerobic drugs especially metronidazole and clindamycin should be performed to generate antibiogram and guide appropriate empiric therapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. [Occurrence and susceptibility to antibiotics of carbapenem-resistant Pseudomonas aeruginosa strains between 1998 and 2009].

    Science.gov (United States)

    Bogiel, Tomasz; Mikucka, Agnieszka; Skalski, Tomasz; Gospodarek, Eugenia

    2010-01-01

    P. aeruginosa rods are dangerous pathogens mainly responsible for nosocomial infections of different localization. Resistance to carbapenems, observed among them, is a serious threat due to ability to be transmitted between bacterial species. The aim of our study was to retrospectively evaluate the frequency of isolation and susceptibility to antibiotics of imipenem- and meropenem-resistant P. aeruginosa strains isolated between 1998 and 2009 from patients of University Hospital No 1 of dr A. Jurasz in Bydgoszcz. Study shows increasing number of isolation that type of strains from 19 in 1998 to 144 in 2009. Among all isolated P. aeruginosa strains majority was obtained from patients of the Intensive Care Units, Rehabilitation and Surgery Clinics. Examined strains of P. aeruginosa rods were mainly isolated from urine (20.5%), bronchoalveolar lavage (17.7%) and wound swabs (14.5%) samples. The isolates demonstrated frequently resistance to carbenicillin (> or 66.7%), ticarcillin (> or = 72.7%) and cefotaxime (> or = 75.6%). The lowest rate of resistant strains was observed in case of ceftazidime (< or = 68.8%), aztreonam (< or = 47.4%) and colistin (< or = 1.7%) suggesting the highest activity of that antimicrobials against infections caused by examined strains.

  1. [Frequency of isolation and susceptibility to antibiotics of Escherichia coli strains isolated from blood].

    Science.gov (United States)

    Białucha, Agata; Budzyńska, Anna; Kozuszko, Sylwia; Gospodarek, Eugenia

    2010-01-01

    The aim of our study was the analysis of Escherichia coli strains obtained from patients of University Hospital No 1 of dr A. Jurasz Collegium Medicum of L. Rydygier in Bydgoszcz Nicolaus Copernicus University in Toruń and State Infectious Diseases Observatory Hospital of T. Browicz in Bydgoszcz, between 2007 and 2010. Among all microorganisms isolated from blood was 8.7% E. coli strains and 45.1% of all rods from Enterobacteriaceae family. Number of E. coli isolations from positive blood samples was: 64 in 2007, 69 in 2008, 77 in 2009 and 26 in the first half of 2010 year. The highest percentage of E. coli strains were obtained from patients of the Transplantology and Surgery Clinic (16.1%), the Nephrology and Internal Diseases Clinic with the Dialysis Centre (14.0%), the Pediatric, Hematology and Oncology Clinic (13.6%) and the Anesthesiology and Intensive Care Clinic (13.6%). All analysed strains were susceptible to carbapenems, amikacin and tygecycline. The highest percentage of resistant strains were observed to ampicillin (70.7%), piperacillin (43.9%), tetracycline (42.8%) and doxycycline (38.8%). During four years of study 4 (6.3%), one, three and two E. coli strains with ESBL were isolated, respectively.

  2. Quality-control ranges for antimicrobial susceptibility testing by broth dilution of the Brachyspira hyodysenteriae type strain (ATCC 27164(T))

    DEFF Research Database (Denmark)

    Pringle, M.; Aarestrup, Frank Møller; Bergsjø, B.

    2006-01-01

    There are no approved standards for antimicrobial susceptibility testing of the fastidious spirochete Brachyspira hyodysenteriae. An interlaboratory study was performed to establish MIC quality control ranges for six antimicrobial agents for the type strain of B. hyodysenteriae using broth diluti...

  3. Differential Expression of Apoptosis Related Genes in Selected Strains of Aedes aegypti with Different Susceptibilities to Dengue Virus

    Science.gov (United States)

    Ocampo, Clara B.; Caicedo, Paola A.; Jaramillo, Gloria; Ursic Bedoya, Raul; Baron, Olga; Serrato, Idalba M.; Cooper, Dawn M.; Lowenberger, Carl

    2013-01-01

    Aedes aegypti is the principal vector of Dengue viruses worldwide. We identified field collected insects with differential susceptibility to Dengue-2 virus (DENv-2) and used isofemale selection to establish susceptible and refractory strains based on midgut infection barriers. Previous experiments had identified higher expression of apoptosis-related genes in the refractory strain. To identify potential molecular mechanisms associated with DENv susceptibility, we evaluated the differential expression of Caspase-16, Aedronc, Aedredd, Inhibitor of apoptosis (AeIAP1) and one member of the RNAi pathway, Argonaute-2 in the midguts and fat body tissues of the selected strains at specific times post blood feeding or infection with DENv-2. In the refractory strain there was significantly increased expression of caspases in midgut and fatbody tissues in the presence of DENv-2, compared to exposure to blood alone, and significantly higher caspase expression in the refractory strain compared with the susceptible strain at timepoints when DENv was establishing in these tissues. We used RNAi to knockdown gene expression; knockdown of AeIAP1 was lethal to the insects. In the refractory strain, knockdown of the pro-apoptotic gene Aedronc increased the susceptibility of refractory insects to DENv-2 from 53% to 78% suggesting a contributing role of this gene in the innate immune response of the refractory strain. PMID:23593426

  4. Antimicrobial susceptibility of Enterococcus strains used in clinical practice as probiotics.

    Science.gov (United States)

    Yamaguchi, Tetsuo; Miura, Yuri; Matsumoto, Tetsuya

    2013-12-01

    The aim of this study was to evaluate the antimicrobial susceptibilities of probiotic strains that are suggested to be effective for preventing antibiotics-associated diarrhea (AAD). The minimum inhibitory concentrations (MICs) of 17 antibiotics against probiotic strains were tested by the agar plate dilution method or broth microdilution method. In all, eight probiotic strains containing Enterococcus faecalis, Bifidobacterium spp., Clostridium butyricum, and Lactobacillus acidophilus were tested. Although the MIC range was wide, from less than 0.0625 to more than 1,024 μg/ml, the MICs of 11 beta-lactams were high for three of four enterococci, with a range of 32 to more than 1,024 μg/ml. In contrast, fluoroquinolones and vancomycin showed potent activities against all enterococci, of which MICs were 0.25-8 μg/ml. Two Bifidobacterium strains and one Lactobacillus strain showed low MICs against many of the beta-lactams, fluoroquinolones, macrolides, and vancomycin, with MICs of 8 μg/ml or less. Fosfomycin showed generally mild activity against enterococci (MIC, 8-32 μg/ml) and anaerobic strains (MIC, 32 to >1,024 μg/ml), respectively. The probiotics strains with high MIC values may survive in the intestinal tract, even if the patient was concomitantly using the antibiotics in clinical practice. Therefore, our results suggest that adequate combinations of probiotics strains and antibiotics should be important for preventing AAD. Further study is needed to determine the efficacy of probiotics in clinical practice.

  5. Different radiation susceptibility among five strains of mice detected by a skin reaction

    Energy Technology Data Exchange (ETDEWEB)

    Iwakawa, Mayumi; Noda, Shuhei; Ohta, Toshie [National Inst. of Radiological Sciences, Chiba (Japan). Frontier Research Center] [and others

    2003-03-01

    Published reports about skin reactions to radiotherapy, especially among breast-cancer patients, suggest that there are interindividual differences in the normal tissue response, and genetic factors are thought to be involved in this variation. An analysis of murine strain differences may reveal the mechanism of genetic factors in the extent of normal tissue damage from irradiation for several endpoints. The variation in the radiation susceptibility was observed when the skin of mice from strains A/J, C3H/HeMs, C57BL/6J, C.B.17/Icr-scid and C3H-scid was irradiated with a single dose ranging from 10 to 60 Gy, using Cs-137 gamma rays. The active skin reaction of A/J mice lasted for months. C3H/HeMs mice showed dose-dependent skin damage, and consequently recovered to a state of mild damage within 40 days after local irradiation. The time course of the response in C57BL/6J mice was shorter than in A/J mice. The 2 strains of scid mice exhibited severe damage after irradiation at any dose from 20 to 50 Gy, and did not show any dose dependency. The variation between murine strains in macroscopic and histopathological changes in skin during the progression and resolution of damage caused by irradiation suggests an inter-strain variation in the expression of genes involved in injury, apoptosis, repair, and remodeling. (author)

  6. Antimicrobial Susceptibility and Biofilm Production by Salmonella sp. Strains Isolated from Frozen Poultry Carcasses

    Directory of Open Access Journals (Sweden)

    MJ Sereno

    Full Text Available ABSTRACT The objectives of this study were to evaluate the antimicrobial resistance and the biofilm-producing ability of Salmonella sp. strains isolated from frozen poultry carcasses. Antimicrobial susceptibility was tested by the disk-diffusion method. Biofilm-producing ability was determined in 96-well polystyrene microplates stained with crystal violet at 1%. Out of the 22 strains tested, all were multiresistant, that is, resistant to more than three antimicrobial classes, and 72.7% were able to form biofilms. The highest resistance rates obtained were against sulfonamides, tetracycline, and quinolones. On the other hand, 100% of the strains were sensitive to chloramphenicol. According to the rate of biofilm formation, 3 (13.6% and 13 (59.1% strains were classified as moderate and weak biofilm-producers, respectively, and 27.3% did not form biofilms. Biofilms increase the tolerance of microorganisms to stress, reducing their sensitivity to disinfectants and antimicrobials; favor equipment corrosion; and act as substrates for the adhesion of bacteria with lower biofilm-producing capacity. The results of the present study stress the importance of cleaning procedures in food processing plants and highlight the public health risks related to the emergence of multiresistant strains.

  7. Susceptibility and resistance to ethanol in Saccharomyces strains isolated from wild and fermentative environments.

    Science.gov (United States)

    Arroyo-López, F N; Salvadó, Z; Tronchoni, J; Guillamón, J M; Barrio, E; Querol, A

    2010-12-01

    In this work, we apply statistical modelling techniques to study the influence of increasing concentrations of ethanol on the overall growth of 29 yeast strains belonging to different Saccharomyces and non-Saccharomyces species. A modified Gompertz equation for decay was used to objectively estimate the noninhibitory concentration (NIC) and minimum inhibitory concentration (MIC) for the assayed strains to ethanol, which are related to the susceptibility and resistance of yeasts to this compound, respectively. A first ANOVA analysis, grouping strains as a function of their respective Saccharomyces species, revealed that S. cerevisiae was the yeast with the highest, and statistically significant, ethanol resistance value. Then, a second factorial ANOVA analysis, using the origin of strains (wild or fermentative) and their taxonomic classification (S. cerevisiae, S. paradoxus or S. bayanus var. uvarum) as categorical predictor variables, showed that no significant differences for the NIC and MIC parameters were found between both ecological niches within the same species, indicative that these physiological characteristics were presumably not modified throughout the adaptation to human-manipulated fermentative environments. Finally, differences among selected strains with respect to ethanol tolerance were correlated to the initial contents of unsaturated fatty acids, mainly oleic acid. Copyright © 2010 John Wiley & Sons, Ltd.

  8. Canadian multicenter laboratory study for standardized second-line antimicrobial susceptibility testing of Mycobacterium tuberculosis.

    Science.gov (United States)

    Sharma, Meenu; Thibert, Louise; Chedore, Pamela; Shandro, Cary; Jamieson, Frances; Tyrrell, Gregory; Christianson, Sara; Soualhine, Hafid; Wolfe, Joyce

    2011-12-01

    The purpose of this study was to establish a standardized protocol for second-line antimicrobial susceptibility testing of Mycobacterium tuberculosis using the Bactec MGIT 960 system in Canadian laboratories. Four Canadian public health laboratories compared the susceptibility testing results of 9 second-line antimicrobials between the Bactec 460 and Bactec MGIT 960 systems. Based on the data generated, we have established that the Bactec MGIT 960 system provides results comparable to those obtained with the previous Bactec 460 method. The critical concentrations established for the testing of the antimicrobials used are as follows: amikacin, 1 μg/ml; capreomycin, 2.5 μg/ml; ethionamide, 5 μg/ml; kanamycin, 2.5 μg/ml; linezolid, 1 μg/ml; moxifloxacin, 0.25 μg/ml; ofloxacin, 2 μg/ml; p-aminosalicylic acid, 4 μg/ml; rifabutin, 0.5 μg/ml.

  9. Canadian Multicenter Laboratory Study for Standardized Second-Line Antimicrobial Susceptibility Testing of Mycobacterium tuberculosis ▿

    Science.gov (United States)

    Sharma, Meenu; Thibert, Louise; Chedore, Pamela; Shandro, Cary; Jamieson, Frances; Tyrrell, Gregory; Christianson, Sara; Soualhine, Hafid; Wolfe, Joyce

    2011-01-01

    The purpose of this study was to establish a standardized protocol for second-line antimicrobial susceptibility testing of Mycobacterium tuberculosis using the Bactec MGIT 960 system in Canadian laboratories. Four Canadian public health laboratories compared the susceptibility testing results of 9 second-line antimicrobials between the Bactec 460 and Bactec MGIT 960 systems. Based on the data generated, we have established that the Bactec MGIT 960 system provides results comparable to those obtained with the previous Bactec 460 method. The critical concentrations established for the testing of the antimicrobials used are as follows: amikacin, 1 μg/ml; capreomycin, 2.5 μg/ml; ethionamide, 5 μg/ml; kanamycin, 2.5 μg/ml; linezolid, 1 μg/ml; moxifloxacin, 0.25 μg/ml; ofloxacin, 2 μg/ml; p-aminosalicylic acid, 4 μg/ml; rifabutin, 0.5 μg/ml. PMID:21998413

  10. The larvicidal effects of black pepper (Piper nigrum L.) and piperine against insecticide resistant and susceptible strains of Anopheles malaria vector mosquitoes.

    Science.gov (United States)

    Samuel, Michael; Oliver, Shüné V; Coetzee, Maureen; Brooke, Basil D

    2016-04-26

    Insecticide resistance carries the potential to undermine the efficacy of insecticide based malaria vector control strategies. Therefore, there is an urgent need for new insecticidal compounds. Black pepper (dried fruit from the vine, Piper nigrum), used as a food additive and spice, and its principal alkaloid piperine, have previously been shown to have larvicidal properties. The aim of this study was to investigate the larvicidal effects of ground black pepper and piperine against third and fourth instar Anopheles larvae drawn from several laboratory-reared insecticide resistant and susceptible strains of Anopheles arabiensis, An. coluzzii, An. gambiae, An. quadriannulatus and An. funestus. Larvae were fed with mixtures of standard larval food and either ground black pepper or piperine in different proportions. Mortality was recorded 24 h after black pepper and 48 h after piperine were applied to the larval bowls. Black pepper and piperine mixtures caused high mortality in the An. gambiae complex strains, with black pepper proving significantly more toxic than piperine. The An. funestus strains were substantially less sensitive to black pepper and piperine which may reflect a marked difference in the feeding habits of this species compared to that of the Gambiae complex or a difference in food metabolism as a consequence of differences in breeding habitat between species. Insecticide resistant and susceptible strains by species proved equally susceptible to black pepper and piperine. It is concluded that black pepper shows potential as a larvicide for the control of certain malaria vector species.

  11. [Drug susceptibility and homologous analysis on Corynebacterium striatum strains isolated from inpatients].

    Science.gov (United States)

    Wang, Junrui; Du, Xiaoli; Cui, Jinghua; Guo, Sufang; Fu, Quan; Wang, Yanyan; Fan, Wenbing; Han, Yanqiu

    2014-08-26

    To explore the molecular epidemiological features and in vitro susceptibility profile of Corynebacterium striatum strains isolated from different sites of inpatients, and further provide new data and idea for clinicians to better get knowledge of the clinical significance of Corynebacterium striatum. Fourty-five strains of Corynebacterium striatum isolated from different sites of inpatients from November, 2013 to March, 2014 in Affiliated hospital of Inner Mongolian medical university, and microdilution method was employed to do in vitro antibiotics susceptibility test. Saline-cotton swab method was used to sample the surrounding environmental surfaces for Corynebacterium striatum carrying patients, and suspected colonies were further identified and in vitro drug susceptibility test were performed. Pulsed Field Gel Electrophoresis(PFGE) method was used to do molecular typing for 41 isolates of Corynebacterium striatum. Fourty-five isolates of Corynebacterium striatum strains were mainly isolated from neurosurgical unit(21 isolates), respiratory unit(8 isolates) and intensive care unit(8 isolates), 39 isolates of which were isolated from lower respiratory tract. The 45 isolates presented an aggregate distribution in the following 3 months, which were December 2013, January 2014 and February 2014.In vitro antibiotics susceptibility test showed that MIC90 for penecillin, erythromycin, tetracycline, ciprofloxacin and clindamycin were 64 µg/ml or higher and the MIC90 for gentamicin, vancomycin and rifampicin were all 0.5 µg/ml. Only one isolate was sensitive to all of the antibiotics tested, except clindamycin. PFGE typing results showed that 41 isolates were divided into 7 genotypes, among which 0002 type and 0006 type were the predominant types and accounted for 63% (26/41) and 22% (9/41), respectively. The isolates from different patients showed high homology, which were isolated from the same unit during the same periods.For surrounding surfaces sampling

  12. Dynamics of sodium dodecyl sulfate utilization andantibiotic susceptibility of strain Pseudomonas sp. ATCC19151

    Directory of Open Access Journals (Sweden)

    Jovčić B.

    2009-01-01

    Full Text Available Pseudomonas sp. ATCC19151 harbors a gene encoding a putative alkylsulfatase (sdsA. Here we report a growth ability of this strain in minimal media containing 0.5, 0.75, and 1% sodium dodecyl sulfate as the sole carbon source. The most prominent growth was detected for the minimal medium with 0.5% SDS, so this concentration of SDS was used to monitor Pseudomonas sp. ATCC19151 SDS biodegradation dynamics. Bacterial growth coincided with the disappearance of SDS. Antibiotic susceptibility was tested as well. Pseudomonas sp. ATCC19151 was resistant to six out of nine tested antibiotics, including ampicillin, tetracycline, chloramphenicol, tobramycin, nalidixic acid, and gentamycin.

  13. The MG1363 and IL1403 Laboratory Strains of Lactococcus lactis and Several Dairy Strains Are Diploid

    DEFF Research Database (Denmark)

    Michelsen, Ole; Hansen, Flemming G.; Albrechtsen, B.

    2010-01-01

    Bacteria are normally haploid, maintaining one copy of their genome in one circular chromosome. We have examined the cell cycle of laboratory strains of Lactococcus lactis, and, to our surprise, we found that some of these strains were born with two complete nonreplicating chromosomes. We...... determined the cellular content of DNA by flow cytometry and by radioactive labeling of the DNA. These strains thus fulfill the criterion of being diploid. Several dairy strains were also found to be diploid while a nondairy strain and several other dairy strains were haploid in slow-growing culture....... The diploid and haploid strains differed in their sensitivity toward UV light, in their cell size, and in their D period, the period between termination of DNA replication and cell division....

  14. Comparison of adhesin genes and antimicrobial susceptibilities between uropathogenic and intestinal commensal Escherichia coli strains.

    Science.gov (United States)

    Qin, Xiaohua; Hu, Fupin; Wu, Shi; Ye, Xinyu; Zhu, Demei; Zhang, Ying; Wang, Minggui

    2013-01-01

    The presence of adhesins is arguably an important determinant of pathogenicity for Uropathogenic Escherichia coli (UPEC). Antimicrobial susceptibilities were tested by agar dilution method, fifteen adhesin genes were detected by polymerase chain reaction, and multilocus sequence typing (MLST) was analyzed in 70 UPEC isolates and 41 commensal E. coli strains. Extended-spectrum β-lactamase (ESBL) was determined with confirmatory test. The prevalence of ESBL-producers in UPEC (53%, 37/70) was higher than the commensal intestinal isolates (7%, 3/41), and 97% (36/37) of the ESBL-producing UPEC harbored bla CTX-M genes. afa was present in 36% (10/28) UPEC isolates from recurrent lower urinary tract infection (UTI), and none in the acute pyelonephritis, acute uncomplicated cystitis or commensal strains (Pcoli, and afa may be associated with recurrent lower UTI whereas papG is more frequently associated with acute pyelonephritis.

  15. Comparison of male reproductive success in malaria-refractory and susceptible strains of Anopheles gambiae

    Directory of Open Access Journals (Sweden)

    Voordouw Maarten J

    2008-06-01

    Full Text Available Abstract Background In female mosquitoes that transmit malaria, the benefits of being refractory to the Plasmodium parasite are balanced by the immunity costs in the absence of infection. Male mosquitoes, however, gain no advantage from being refractory to blood-transmitted parasites, so that any costs associated with an enhanced immune system in the males limit the evolution of female refractoriness and has practical implications for the release of transgenic males. Methods Aspects of the male cost of carrying Plasmodium-refractory genes were estimated by comparing the males' immune response and reproductive success among strains of Anopheles gambiae that had been selected for refractoriness or extreme susceptibility to the rodent malaria parasite, Plasmodium yoelii nigeriensis. The refractory males had a stronger melanization response than males from the susceptible line. Four traits were used as correlates of a male's reproductive success: the proportion of females that were inseminated by a fixed number of males in a cage within a fixed time frame, the proportion of females with motile sperm in their spermathecae, the proportion of ovipositing females, and the mean number of eggs per batch. Results Although there were significant differences among groups of males in sperm motility and oviposition success, these differences in male reproductive success were not associated with the refractory or susceptible male genotypes. Contrary to expectation, females mated to early emerging refractory males laid significantly more eggs per batch than females mated to later emerging susceptible males. Sperm motility and oviposition success were strongly correlated suggesting that variation in sperm motility influences female oviposition and ultimately male reproductive success. Conclusion An increased melanization response in male A. gambiae does not diminish male reproductive success under the experimental protocol used in this study. That refractory

  16. Differential susceptibility in steelhead trout populations to an emergent MD strain of infectious hematopoietic necrosis virus

    Science.gov (United States)

    Breyta, R.; Jones, Amelia; Kurath, Gael

    2014-01-01

    A significant emergence of trout-adapted MD subgroup infectious hematopoietic necrosis virus (IHNV) began in the coastal region of Washington State, USA, in 2007. This emergence event lasted until 2011 and caused both asymptomatic adult fish infection and symptomatic epidemic disease and mortality in juvenile fish. Incidence of virus during this emergence demonstrated a heterogeneous distribution among rivers of the coastal region, leaving fish populations of some rivers apparently untouched while others suffered significant and recurrent infection and mortality (Breyta et. al. 2013; Dis Aquat Org 104:179-195). In this study, we examined the possible contribution of variations in susceptibility of fish populations, age-related resistance, and virus virulence to the observed landscape heterogeneity. We found that the most significant variable was host susceptibility: by controlled experimental challenge studies steelhead trout populations with no history of IHNV infection were 1 to 3 orders of magnitude more sensitive than a fish population with a long history of IHNV infection. In addition, 2 fish populations from the same river, which descended relatively recently from a common ancestral population, demonstrated 1 to 2 orders of magnitude difference in susceptibility. Fish age-related development of resistance was most evident in the more susceptible of 2 related fish populations. Finally, the strain of virus involved in the 2007 coastal Washington emergence had high virulence but was within the range of other known M group viruses tested. These results suggest that one major driver of landscape heterogeneity in the 2007 coastal Washington IHNV emergence was variation in fish population susceptibility and that this trait may have a heritable component.

  17. Rapid identification of Mycobacterium avium ssp paratuberculosis laboratory strains by IS900-Nested polymerase chain reaction

    Directory of Open Access Journals (Sweden)

    Mohammad Mohammad Taheri

    2016-01-01

    Conclution: However, no amplification was observed with other strains. Two main achievements of this work are the development of an efficient means of differentiation between the six Razi laboratory mycobacterial strains and characterization of the genomic profile of these strains, a capability that is vital when cross contamination is potentially an important concern.

  18. Susceptibility to tigecycline of Acinetobacter baumannii strains isolated from intensive care unit patients.

    Science.gov (United States)

    Talaga, Katarzyna; Krzyściak, Paweł; Bulanda, Małgorzata

    2016-01-01

    Infections caused by Acinetobacter baumannii are difficult to cure due to the acquisition of resistance by these bacteria and lead to an increase in the general costs of hospitalization. The aim of this study was to determine tigecycline susceptibility of Acinetobacter baumannii strains isolated from intensive care unit and non-intensive care unit patients with skin and soft tissue infections. MICs were tested by Etest among 70 Acinetobacter baumannii isolates. The MIC range was from 0.5 to 8.0 mg L⁻¹. For ESBL-producing Acinetobacter baumannii, as well as for strains without carbapenemases, the highest MIC to tigecycline value was 8.0 mg L⁻¹. For AmpC-producing Acinetobacter baumannii, the highest MIC to tigecycline value was 6.0 mg L⁻¹ and, for MBL-producing strains, 2.0 mg L⁻¹. The majority of Acinetobacter baumannii strains isolated from ICU and non-ICU patients demonstrated high values of MIC range, MIC50 and MIC90 to tigecycline.

  19. Larvicidal and Adulticidal Activity of Chroman and Chromene Analogues against Susceptible and Permethrin-Resistant Mosquito Strains.

    Science.gov (United States)

    Meepagala, Kumudini M; Estep, Alden S; Becnel, James J

    2016-06-22

    Mosquitoes play a major role as vectors that transmit parasitic and viral diseases worldwide, especially in tropical and subtropical countries. Mosquito borne diseases not only affect humans but they also affect livestock in many parts of the world. They carry diseases that are lethal to dogs and horses. Dog heartworm disease (Dirofilaria immitis) is a parasitic disease spread through mosquitoes. This disease is not limited to dogs, but it can affect other animals and humans as well. Eastern equine encephalitis (EEE) and West Nile virus (WNV) are also mosquito borne diseases that affect the central nervous system of horses and cause severe complications and death. Emergence of resistance among mosquitoes to current pesticides has increased the importance of the search for alternate compounds that are effective and environmentally benign with diverse modes of actions than those that are commercially available. Aedes aegypti mosquitoes are the primary vector for transmission of Zika viral fever, yellow fever, dengue fever, and chikungunya. Mosquito control is currently the best strategy to prevent mosquito borne diseases. There are numerous approaches for control of potentially dangerous mosquito populations. These approaches include the use of adulticides (insecticides), larvicides, and, to a limited extent, the use of repellents. Our previous studies have shown the mosquito repellent activity of chromenes. In the present study, we demonstrate larvicidal and adulticidal activity of chroman and chromene analogues against a permethrin susceptible laboratory strain as well as activity against a permethrin-resistant strain of Aedes aegypti.

  20. Antibiotic susceptibility profiles of Mycoplasma sp. 1220 strains isolated from geese in Hungary.

    Science.gov (United States)

    Grózner, Dénes; Kreizinger, Zsuzsa; Sulyok, Kinga M; Rónai, Zsuzsanna; Hrivnák, Veronika; Turcsányi, Ibolya; Jánosi, Szilárd; Gyuranecz, Miklós

    2016-08-19

    Mycoplasma sp. 1220 can induce inflammation primarily in the genital and respiratory tracts of waterfowl, leading to serious economic losses. Adequate housing and appropriate antibiotic treatment are promoted in the control of the disease. The aim of the present study was to determine the in vitro susceptibility to thirteen different antibiotics and an antibiotic combination of thirty-eight M. sp. 1220 strains isolated from geese and a duck in several parts of Hungary, Central Europe between 2011 and 2015. High MIC50 values were observed in the cases of tilmicosin (>64 μg/ml), oxytetracycline (64 μg/ml), norfloxacin (>10 μg/ml) and difloxacin (10 μg/ml). The examined strains yielded the same MIC50 values with spectinomycin, tylosin and florfenicol (8 μg/ml), while enrofloxacin (MIC50 5 μg/ml), doxycycline (MIC50 5 μg/ml), lincomycin (MIC50 4 μg/ml) and lincomycin-spectinomycin (1:2) combination (MIC50 4 μg/ml) inhibited the growth of the bacteria with lower concentrations. Tylvalosin (MIC50 0.5 μg/ml) and two pleuromutilins (tiamulin MIC50 0.625 μg/ml; valnemulin MIC50 ≤ 0.039 μg/ml) were found to be the most effective drugs against M. sp. 1220. However, strains with elevated MIC values were detected for all applied antibiotics. Valnemulin, tiamulin and tylvalosin were found to be the most effective antibiotics in the study. Increasing resistance was observed in the cases of several antibiotics. The results highlight the importance of testing Mycoplasma species for antibiotic susceptibility before therapy.

  1. Susceptibility of selected strains used for evaluation of biocidal efficiency of disinfectants and antibiotic-resistant strains to didecyldimethylammonium chloride in 2-propanol.

    Science.gov (United States)

    Chojecka, Agnieszka; Wiercińska, Olga; Röhm-Rodowald, Ewa; Kanclerski, Krzysztof; Jakimiak, Bożenna

    2015-01-01

    Didecyldimethylammonium chloride is an active substance which is part of variety of formulations used for the disinfection and antisepsis, both in the medical area as well as in the food, industrial and institutional area. Because of the widespread use of this substance and the development of bacterial resistance to quaternary ammonium compounds (QACs), the aim of this study was determination of the susceptibility of the standard strains used for the evaluation of the effectiveness of disinfectants and standard antibiotic-resistant strains to didecyldimethylammonium chloride in 2-propanol and its bactericidal activity. Susceptibility of standard strains used for the evaluation of the effectiveness of disinfectants (Staphylococcus aureus ATCC 6538-SA; Pseudomonas aeruginosa ATCC 15442-PA) and standard antibiotic-resistant strains (Staphylococcus aureus ATCC 43300-MRSA; Pseudomonas aeruginosa ATCC 47085-PAO-LAC) to CMAP was determined by minimum inhibitory concentrations (MICs) and minimum bactericidal concentration (MBCs). The bactericidal efficiency of CMAP against these strains was evaluated by using phenol coefficient (PC). Susceptibility of Gram-positive tested strains SA and MRSA to CMAP was similar (P>0,05). Significant difference in susceptibility of tested Gram-negative strains to CMAP was evaluated between PA and PAO-LAC strains (P<0,05). However,.higher resistance of PAO-LAC to CMAP was not significant when parameters such as concentration and contact time were applied in PC method. The correct determination and application of "in use" parameters (i.e. concentration, contact time, temperature and interfering substances) in disinfection process prevents the spread of resistant strains in.the environment.

  2. Antibiotic susceptibility profiles of Mycoplasma synoviae strains originating from Central and Eastern Europe.

    Science.gov (United States)

    Kreizinger, Zsuzsa; Grózner, Dénes; Sulyok, Kinga M; Nilsson, Kristin; Hrivnák, Veronika; Benčina, Dušan; Gyuranecz, Miklós

    2017-11-17

    Mycoplasma synoviae causes infectious synovitis and respiratory diseases in chickens and turkeys and may lead to egg shell apex abnormalities in chickens; hence possesses high economic impact on the poultry industry. Control of the disease consists of eradication, vaccination or medication. The aim of the present study was to determine the in vitro susceptibility to 14 different antibiotics and an antibiotic combination of M. synoviae strains originating from Hungary and other countries of Central and Eastern Europe. Minimal inhibitory concentration (MIC) values of a total of 41 M. synoviae strains were determined by the microbroth dilution method. The strains were collected between 2002 and 2016 and originated from Hungary (n = 26), Austria (n = 3), the Czech Republic (n = 3), Slovenia (n = 3), Ukraine (n = 3), Russia (n = 2) and Serbia (n = 1). Tetracyclines (with MIC 50 values of 0.078 μg/ml, ≤0.25 μg/ml and 0.5 μg/ml for doxycycline, oxytetracycline and chlortetracycline, respectively), macrolides (with MIC 50 values of ≤0.25 μg/ml for tylvalosin, tylosin and tilmicosin), pleuromutilins (with MIC 50 values of 0.078 μg/ml and ≤0.039 μg/ml for tiamulin and valnemulin) and the combination of lincomycin and spectinomycin (MIC 50 1 μg/ml (0.333/0.667 μg/ml)) were found to be the most effective antibiotic agents against M. synoviae in vitro. High MIC values were detected in numerous strains for fluoroquinolones (with MIC 50 values of 1.25 μg/ml and 2.5 μg/ml for enrofloxacin and difloxacin), neomycin (MIC 50 32 μg/ml), spectinomycin (MIC 50 2 μg/ml), lincomycin (MIC 50 0.5 μg/ml) and florfenicol (MIC 50 4 μg/ml). Nevertheless, strains with elevated MIC values were detected for most of the applied antibiotics. In the medical control of M. synoviae infections the preliminary in vitro antibiotic susceptibility testing and the careful evaluation of the data are crucial. Based on the in vitro examinations

  3. Slow Strain Rate Testing for Hydrogen Embrittlement Susceptibility of Alloy 718 in Substitute Ocean Water

    Science.gov (United States)

    LaCoursiere, M. P.; Aidun, D. K.; Morrison, D. J.

    2017-05-01

    The hydrogen embrittlement susceptibility of near-peak-aged UNS N07718 (Alloy 718) was evaluated by performing slow strain rate tests at room temperature in air and substitute ocean water. Tests in substitute ocean water were accomplished in an environmental cell that enabled in situ cathodic charging under an applied potential of -1.1 V versus SCE. Some specimens were cathodically precharged for 4 or 16 weeks at the same potential in a 3.5 wt.% NaCl-distilled water solution at 50 °C. Unprecharged specimens tested in substitute ocean water exhibited only moderate embrittlement with plastic strain to failure decreasing by about 20% compared to unprecharged specimens tested in air. However, precharged specimens exhibited significant embrittlement with plastic strain to failure decreasing by about 70%. Test environment (air or substitute ocean water with in situ charging) and precharge time (4 or 16 weeks) had little effect on the results of the precharged specimens. Fracture surfaces of precharged specimens were typical of hydrogen embrittlement and consisted of an outer brittle ring related to the region in which hydrogen infused during precharging, a finely dimpled transition zone probably related to the region where hydrogen was drawn in by dislocation transport, and a central highly dimpled ductile region. Fracture surfaces of unprecharged specimens tested in substitute ocean water consisted of a finely dimpled outer ring and heavily dimpled central region typical of ductile fracture.

  4. Six-year susceptibility trends and effect of revised Clinical Laboratory Standards Institute breakpoints on ciprofloxacin susceptibility reporting in typhoidal Salmonellae in a tertiary care paediatric hospital in Northern India

    Directory of Open Access Journals (Sweden)

    R Saksena

    2016-01-01

    Full Text Available The antimicrobial trends over 6 years were studied, and the effect of revised Clinical Laboratory Standards Institute (CLSI breakpoints (2012 for ciprofloxacin susceptibility reporting in typhoidal Salmonellae was determined. A total of 874 (95.4% isolates were nalidixic acid-resistant (NAR. Using the CLSI 2011 guidelines (M100-S21, 585 (66.9% isolates were ciprofloxacin susceptible. The susceptibility reduced to 11 (1.25% isolates when interpreted using 2012 guidelines (M100-S22. Among the forty nalidixic acid susceptible (NAS Salmonellae, susceptibility to ciprofloxacin decreased from 37 isolates (M100-S21 to 12 isolates (M100-S22. The 25 cases which appeared resistant with newer guidelines had a minimum inhibitory concentration (MIC range between 0.125 and 0.5 μg/ml. MIC50 for the third generation cephalosporins varied between 0.125 and 0.5 μg/ml over 6 years whereas MIC90 varied with a broader range of 0.19–1 μg/ml. The gap between NAR and ciprofloxacin-resistant strains identified using 2011 guidelines has been reduced; however, it remains to be seen whether additional NAS, ciprofloxacin-resistant isolates are truly resistant to ciprofloxacin by other mechanisms of resistance.

  5. Effect of antimicrobial peptides on colistin-susceptible and colistin-resistant strains of Klebsiella pneumoniae and Enterobacter asburiae.

    Science.gov (United States)

    Kádár, Béla; Kocsis, Béla; Kristof, Katalin; Tóth, Ákos; Szabó, Dóra

    2015-12-01

    In this study susceptibility to different antimicrobial peptides was investigated on colistin-susceptible and colistin-resistant identical pulsotype strains of KPC-2 producing Klebsiella pneumoniae ST258 as well as colistin-susceptible and colistin-resistant Enterobacter asburiae strains isolated from clinical samples. In our test, bacteria were exposed to 50 mg/ml lactoferrin, lysozyme and protamine - cationic antimicrobial peptides belonging to innate immune system and having structural similarity to polymyxins - in separate reactions. After 18 hours incubation of colonies were counted. 40% of colistin-resistant K. pneumoniae strains and 97% of colistin-susceptible counterpart strains were lysed by protamine whereas 87% and 100% colony forming unit decrease by lysozyme was seen, respectively. In the case of colistin-resistant E. asburiae strains 1 log10 cell count increase were observed after treatment with lysozyme and 1.56 log10 after lactoferrin exposure compared to the initial number whereas the colistin-susceptible showed no relevant cell count increase. Our findings suggest that acquired colistin-resistance in Enterobacteriaceae is associated with tolerance against antimicrobial peptides.

  6. Efficiency of oxytetracycline treatment in rainbow trout experimentally infected with Flavobacterium psychrophilum strains having different in vitro antibiotic susceptibilities

    DEFF Research Database (Denmark)

    Bruun, Morten Sichlau; Madsen, Lone; Dalsgaard, Inger

    2003-01-01

    The medication effect of oxytetracycline on groups of rainbow trout fry experimentally infected with three strains of Flavobacterium psychrophilum was investigated. The infection model was based on intraperitoneal injection of the pathogen and treatment was done using medicated feed resulting...... in 100 mg oxytetracycline/kg fish for 10 days. The three F. psychrophilum strains had different antimicrobial susceptibilities and successful treatment was only obtained in the trial using a strain with a MICOTC of 0.25 mug/ml. No effect of treatment was seen in the group infected with a strain having...... MICOTC of 8.0 mug/ml and only little effect was seen when the strain MICOTC was 4.0 mug/ml. This shows that it is valid to predict the treatment efficiency of OTC from in vitro data facing an outbreak of rainbow trout fry syndrome. The importance of doing susceptibility testing is emphasized...

  7. Phenotypic dissection of a Plasmodium-refractory strain of malaria vector Anopheles stephensi: the reduced susceptibility to P. berghei and P. yoelii.

    Directory of Open Access Journals (Sweden)

    Naoaki Shinzawa

    Full Text Available Anopheline mosquitoes are the major vectors of human malaria. Parasite-mosquito interactions are a critical aspect of disease transmission and a potential target for malaria control. Current investigations into parasite-mosquito interactions frequently assume that genetically resistant and susceptible mosquitoes exist in nature. Therefore, comparisons between the Plasmodium susceptibility profiles of different mosquito species may contribute to a better understanding of vectorial capacity. Anopheles stephensi is an important malaria vector in central and southern Asia and is widely used as a laboratory model of parasite transmission due to its high susceptibility to Plasmodium infection. In the present study, we identified a rodent malaria-refractory strain of A. stephensi mysorensis (Ehime by comparative study of infection susceptibility. A very low number of oocysts develop in Ehime mosquitoes infected with P. berghei and P. yoelii, as determined by evaluation of developed oocysts on the basal lamina. A stage-specific study revealed that this reduced susceptibility was due to the impaired formation of ookinetes of both Plasmodium species in the midgut lumen and incomplete crossing of the midgut epithelium. There were no apparent abnormalities in the exflagellation of male parasites in the ingested blood or the maturation of oocysts after the rounding up of the ookinetes. Overall, these results suggest that invasive-stage parasites are eliminated in both the midgut lumen and epithelium in Ehime mosquitoes by strain-specific factors that remain unknown. The refractory strain newly identified in this report would be an excellent study system for investigations into novel parasite-mosquito interactions in the mosquito midgut.

  8. Clusterin and Pycr1 alterations associate with strain and model differences in susceptibility to experimental pancreatitis.

    Science.gov (United States)

    Iyer, Sapna; Park, Min-Jung; Moons, David; Kwan, Raymond; Liao, Jian; Liu, Li; Omary, M Bishr

    2017-01-22

    Acute pancreatitis has several underlying etiologies, and results in consequences ranging from mild to complex multi-organ failure. The wide range of pathology suggests a genetic predisposition for progression. We compared the susceptibility to acute pancreatitis in BALB/c and FVB/N mice, coupled with proteomic analysis, in order to identify potential protein associations with pancreatitis progression. Pancreatitis was induced in BALB/c and FVB/N mice by administration of cerulein or feeding a choline-deficient, ethionine-supplemented (CDE) diet. Histology and changes in serum amylase were examined. Proteome profiling in cerulein-treated mice was performed using 2-dimensional differential in gel electrophoresis (2D-DIGE) followed by mass spectrometry analysis and biochemical validation. Male and female FVB/N mice manifested more severe cerulein-induced pancreatitis as compared with BALB/c mice, but both strains were similarly susceptible to CDE-induced pancreatitis. Few of the 2D-DIGE alterations were validated by immunoblotting. Clusterin was markedly up-regulated after cerulein-induced pancreatitis in FVB/N but less-so in BALB/c mice. Pyrroline-5-carboxylate reductase (Pycr1), an enzyme involved in proline biosynthesis, had higher basal levels in FVB/N male and female mouse pancreata compared with BALB/c pancreata, and was relatively more resistant to degradation in FVB/N pancreata. However, serum and pancreas tissue proline levels were similar in the two strains. FVB/N is more susceptible than BALB/c mice to cerulein-induced but not CDE-induced pancreatitis. Most of the 2D-DIGE alterations in the two strains likely relate to posttranslational modifications rather than protein level differences. Clusterin levels increase dramatically in association with pancreatitis severity, while Pycr1 is higher in FVB/N versus BALB/c pancreata basally and after induction of pancreatitis. Changes in proline metabolism may represent a novel potential genetic modifier in the

  9. Genetic and biochemical analysis of a laboratory-selected spirodiclofen-resistant strain of Tetranychus urticae Koch (Acari: Tetranychidae).

    Science.gov (United States)

    Van Pottelberge, Steven; Van Leeuwen, Thomas; Khajehali, Jahangir; Tirry, Luc

    2009-04-01

    Spirodiclofen is a selective, non-systemic acaricide from the new chemical class of tetronic acid derivatives. In order to develop strategies to minimise resistance in the field, a laboratory-selected spirodiclofen-resistant strain of the two-spotted spider mite, Tetranychus urticae Koch, was used to determine genetic, toxicological, biochemical and cross-resistance data. Selecting for spirodiclofen resistance in the laboratory yielded a strain (SR-VP) with a resistance ratio of 274, determined on the larval stage. The egg stage remained far more susceptible. No cross-resistance was found against other established acaricides, except for spiromesifen. Based on synergist experiments and enzyme assays, it appeared that especially P450 monooxygenases, but also esterases and glutathione-S-transferases, could be involved in the metabolic detoxification of spirodiclofen. Genetic analysis showed that the resistance is inherited as an intermediate trait under control of more than one gene. Resistance to spirodiclofen exceeded by far the recommended field rate. A good acaricide resistance management programme is necessary to prevent fast resistance build-up in the field. Spirodiclofen can be used in alternation with most established acaricides, except for other tetronic acid derivatives. Without selection pressure, resistance tends to be unstable and can decrease in the presence of susceptible individuals owing to the intermediate, polygenic inheritance mode. Copyright (c) 2009 Society of Chemical Industry.

  10. [Identification and susceptibility against fluconazole and albaconazole of 100 yeasts' strains isolated from vaginal discharge].

    Science.gov (United States)

    Arechavala, Alicia I; Bianchi, Mario H; Robles, Ana María; Santiso, Gabriela; Negroni, Ricardo

    2007-12-31

    Vulvovaginal candidiasis is a condition that affects a great number of fertile women. It is considered the second cause of genital infection after vaginosis due to GAM complex. Candida albicans is the most frequent isolated species from vaginal discharge. However, sometimes more than one yeast species could be found in the same clinical sample that are more resistant to antifungal drugs. Nowadays, it is necessary to identify properly up to species level the isolated microorganism and to determine the antifungal susceptibility profile. One hundred strains obtained from vaginal discharge of 94 patients suffering acute vulvovaginal candidiasis were studied. The identification of the isolates showed: C. albicans 86%, Candida glabrata 6%, Candida inconspicua 3%, Candida krusei 2% and Candida intermedia, Candida holmii and Trichosporon asahii one case each. Minimal inhibitory concentrations (MIC) of all the yeasts against fluconazole and albaconazole were performed. C. glabrata, C. krusei and C. inconspicua were the most resistant against fluconazole, on the other hand albicans was susceptible to this drug. All the isolates presented MIC against albaconazole much lower than fluconazole.

  11. The Colour Test for drug susceptibility testing of Mycobacterium tuberculosis strains.

    Science.gov (United States)

    Toit, K; Mitchell, S; Balabanova, Y; Evans, C A; Kummik, T; Nikolayevskyy, V; Drobniewski, F

    2012-08-01

    Tartu, Estonia. To assess the performance and feasibility of the introduction of the thin-layer agar MDR/XDR-TB Colour Test (Colour Test) as a non-commercial method of drug susceptibility testing (DST). The Colour Test combines the thin-layer agar technique with a simple colour-coded quadrant format, selective medium to reduce contamination and colorimetric indication of bacterial growth to simplify interpretation. DST patterns for isoniazid (INH), rifampicin (RMP) and ciprofloxacin (CFX) were determined using the Colour Test for 201 archived Mycobacterium tuberculosis isolates. Susceptibilities were compared to blinded DST results obtained routinely using the BACTEC™ Mycobacteria Growth Indicator Tube™ (MGIT) 960 to assess performance characteristics. In all, 98% of the isolates produced interpretable results. The average time to positivity was 13 days, and all results were interpretable. The Colour Test detected drug resistance with 98% sensitivity for INH, RMP and CFX and 99% for multidrug-resistant tuberculosis. Specificities were respectively 100% (95%CI 82-100), 88% (95%CI 69-97) and 91% (95%CI 83-96) and 90% (95%CI 74-98). Agreement between the Colour Test and BACTEC MGIT 960 were respectively 98%, 96%, 94% and 97%. The Colour Test could be an economical, accurate and simple technique for testing tuberculosis strains for drug resistance. As it requires little specialist equipment, it may be particularly useful in resource-constrained settings with growing drug resistance rates.

  12. Relative susceptibility of stream macroinvertebrates to temephos and chlorpyrifos, determined in laboratory continuous-flow systems.

    Science.gov (United States)

    Muirhead-Thomson, R C

    1978-01-01

    Laboratory techniques are described for evaluating the lethal and behavioral impact of pesticides on a range of stream macroinvertebrates under continuous through-flow and simulated stream conditions. The same basic test unit has been used, with slight modifications, to study the reactions of both Simulium larvae and non-target stream invertebrates. On the basis of a standard 1-hr exposure period to different concentrations followed by a 24-hr holding period in a continuous flow of clean water, different test organisms showed wide and consistent differences in tolerance to each of the two insecticides tested. The widest difference between two organisms occurred in the case of the Amphipod, Gammarus pulex (LC90-95, greater than 1 ppm) which was found to be about 5000 x more tolerant to temephos than are nymphs of the mayfly, Baetis rhodani. (LC 90-95, 0.001-0.002 ppm) The widest difference in the reactions of any one species is shown on the part of Gammarus which is about 100 times more susceptible to chlorpyrifos (LC 90-95, 0.05-0.1 ppm) than to temephos. The susceptibility levels of other indicator species such as Agrion, Hydropsyche, Brachycentrus, Ephemera, etc. are discussed in relation to susceptibility levels of Simulium larvae under the same test conditions, and also in relation to current field dosages of the two insecticides in practical and experimental Simulium control.

  13. Morphological Characteristics of Schistosoma mansoni PZQ-resistant and -susceptible Strains are Different in Presence of Praziquantel

    Directory of Open Access Journals (Sweden)

    António ePinto-Almeida

    2016-04-01

    Full Text Available Schistosomiasis is one of the most common human parasitic diseases whose socioeconomic impact is only surpassed by malaria. Praziquantel (PZQ is the only drug commercially available for the treatment of all schistosome species causing disease in humans. However, there has been stronger evidences of PZQ-resistance on Schistosoma mansoni and thus it is very important to study the phenotypic characteristics associated with it. The aim of this study was to evaluate morphological alterations in S. mansoni PZQ-resistant adult worms and eggs, by comparing a PZQ-resistant strain obtained under PZQ drug pressure with a PZQ-susceptible strain. For this, scanning electronic microscopy was used to assess tegumental responsiveness of both strains under PZQ exposure, and optical microscopy allowed the monitoring of worms and eggs in the presence of the drug. Those assays showed that PZQ-susceptible worms exposed to the drug had more severe tegumental damages than the resistant one, which had only minor alterations. Moreover, contrary to what occurred in the susceptible strain, resistant worms were viable after PZQ exposure and gradually regaining full motility after removal of the drug. Eggs from resistant strain parasites are considerably smaller than those from susceptible strain. Our results suggest that there might be a difference in the tegument composition of the resistant strain and that worms are less responsive to PZQ. Changes observed in egg morphology might imply alterations in the biology of schistosomes associated to PZQ-resistance, which could impact on transmission and pathology of the disease. Moreover, we propose a hypothetical scenario where there is a different egg tropism of the S. mansoni resistant strain. This study is the first comparing two strains that only differ in their resistance characteristics, which makes it a relevant step in the search for resistance determinants.

  14. Drug susceptibility testing of Mycobacterium tuberculosis to fluoroquinolones

    DEFF Research Database (Denmark)

    Johansen, I S; Larsen, A R; Sandven, P

    2003-01-01

    In the first attempt to establish a quality assurance programme for susceptibility testing of Mycobacterium tuberculosis to fluoroquinolones, 20 strains with different fluoroquinolone susceptibility patterns were distributed by the Supranational Reference Laboratory in Stockholm to the other...

  15. Termite-Susceptible Species of Wood for Inclusion as a Reference in Indonesian Standardized Laboratory Testing.

    Science.gov (United States)

    Arinana; Tsunoda, Kunio; Herliyana, Elis N; Hadi, Yusuf S

    2012-03-28

    Standardized laboratory testing of wood and wood-based products against subterranean termites in Indonesia (SNI 01.7207-2006) (SNI) has no requirement for the inclusion of a comparative reference species of wood (reference control). This is considered a weakness of the Indonesian standard. Consequently, a study was undertaken to identify a suitable Indonesian species of community wood that could be used as a reference control. Four candidate species of community woods: Acacia mangium, Hevea brasiliensis, Paraserianthes falcataria and Pinus merkusii were selected for testing their susceptibility to feeding by Coptotermes formosanus. Two testing methods (SNI and the Japanese standard method JIS K 1571-2004) were used to compare the susceptibility of each species of wood. Included in the study was Cryptomeria japonica, the reference control specified in the Japanese standard. The results of the study indicated that P. merkusii is a suitable reference species of wood for inclusion in laboratory tests against subterranean termites, conducted in accordance with the Indonesian standard (SNI 01.7207-2006).

  16. Genetic Susceptibility to Norovirus GII.4 Sydney Strain Infections in Taiwanese Children.

    Science.gov (United States)

    Tu, Li-Tzu; Liu, Fu-Ping; Huang, Yhu-Chering; Huang, Chung-Guei; Yang, Shuan; Tsao, Kuo-Chien; Lai, Ming-Wei; Chen, Chih-Jung

    2017-04-01

    A comprehensive evaluation of associations between the susceptibility to norovirus infections and histo-blood group antigens is not available in the Taiwanese population, in which the nonsecretor phenotype is absent. A 1:1 matched case-control study was conducted in northern Taiwan from February 2013 to December 2014 when an epidemic of norovirus infection occurred. Cases were children norovirus infections. Controls were healthy children matched to the cases by age and gender. The norovirus genotype was determined by polymerase chain reaction sequencing of the VP1 gene. The secretor status, Lewis antigen and ABO type were determined by characterization of genetic polymorphisms in the FUT2, FUT3 and ABO genes, respectively. A total of 147 case-control pairs were included. GII.4 Sydney strain was the major genotype and identified in 78.3% of the cases. The weak-secretor and Lewis-positive genotypes were less commonly identified in cases than in controls (5.4% vs. 23.1% and 79.6% vs. 89.8%, respectively). Multivariate analysis revealed that the secretor and Lewis-negative genotypes were both independent factors associated with increased risk of norovirus infections [matched odds ratio: 6.766, 95% confidence interval (CI): 2.649-17.285, P norovirus infections (P > 0.05). The weak-secretor genotype and the Lewis antigen-positive genotype were both protective factors against severe norovirus gastroenteritis during the GII.4 Sydney strain epidemic in Taiwan.

  17. Antibiotic susceptibility of Legionella strains isolated from public water sources in Macau and Guangzhou.

    Science.gov (United States)

    Xiong, Lina; Yan, He; Shi, Lei; Mo, Ziyao

    2016-12-01

    The purpose of this study was to investigate the susceptibility of waterborne strains of Legionella to eight antimicrobials commonly used in legionellosis therapy. The minimum inhibitory concentrations (MICs) of 66 environmental Legionella strains, isolated from fountains and cooling towers of public facilities (hotels, schools, and shopping malls) in Macau and Guangzhou, were tested using the microdilution method in buffered yeast extract broth. The MIC50/MIC90 values for erythromycin, cefotaxime (CTX), doxycycline (DOC), minocycline (MIN), azithromycin, ciprofloxacin, levofloxacin (LEV), and moxifloxacin were 0.125/0.5 mg/L, 4/8 mg/L, 8/16 mg/L, 4/8 mg/L, 0.125/0.5 mg/L, 0.031/0.031 mg/L, 0.031/0.031 mg/L, and 0.031/0.062 mg/L, respectively. Legionella isolates were inhibited by either low concentrations of macrolides and fluoroquinolones, or high concentrations of CTX and tetracycline drugs. LEV was the most effective drug against different Legionella species and serogroups of L. pneumophila isolates. The latter were inhibited in decreasing order by MIN > CTX >DOC, while non-L. pneumophila isolates were inhibited by CTX> MIN >DOC. In this study, we evaluated drug resistance of pathogenic bacteria from the environment. This may help predict the emergence of drug resistance, improve patient outcomes, and reduce hospitalization costs.

  18. Isolation of Klebsiella pneumoniae strains with altered susceptibility to carbapenems not carbapenemase mediated

    Directory of Open Access Journals (Sweden)

    Franca Cian

    2009-12-01

    Full Text Available The spread of enterobacteria producing extended-spectrum ß-lactamases (ESBLs is sharply increasing in Italy, while the detection of isolates resistant to carbapenems is still sporadic. Isolates of Klebsiella pneumoniae resistant to all cephalosporins, aminoglycosides and fluoroquinolones have been isolated in Trieste since 2008. Because of the altered profile of resistance to carbapenems, these strains were reported as ESBL-negative and possible carbapenemases producer by the expert system, leaving tigecycline as the only therapeutic choice.The purpose of this study is the characterization of the mechanisms involved in resistance to carbapenems in these strains and the evaluation of a reliable and simple test for phenotypic confirmation of ESBL and/or carbapenemase production. 25 isolates of MDR K. pneumoniae were collected between October 2008 and May 2009, mainly from urinary samples of elderly patients hospitalized in medicine wards. Identification and susceptibility testing were performed using the Vitek 2 system.The double-disc (DD test was used to check the production of ESBLs, while imipenem and imipenem-EDTA synergy test was used to detect the production of metallo-ßlactamase (MBL. Carbapenemase activity was tested by an hydrolysis assay and the production of MBLs was also investigated by PCR. The DD synergy test highlighted the possible production of ESBLs in 18 out of 22 strains, considered as negative by Vitek. All ESBLs producers tested positive for the blaCTX-M-15 allele. Only one isolate was resistant to carbapenems and resulted positive for production of MBL by the phenotypic test.The crude extract showed carbapenemase activity inhibited by EDTA; PCR test gave positive result for a blaVIM-type allele. PCR analysis performed on representative isolates, followed by sequencing, showed that coding sequence of ompk35 was not functional. Results of this study confirmed the emergence of ESBL-positive strains of K. pneumoniae that

  19. IMPACT OF DIFFERENT ENVIRONMENTAL PARAMETERS UPON THE SUSCEPTIBILITY TO HEAVY METALS SALTS IN ESCHERICHIA COLI AQUATIC STRAINS

    OpenAIRE

    Emilia Panus; Mariana Carmen Chifiriuc; Coralia Bleotu; Magda Mitache; Natalia Rosoiu

    2012-01-01

    Purpose: to investigate the relationships among the expression of susceptibility to heavy metal salts, different incubation temperatures and chemical composition of the culture media in E. coli aquatic strains. 100 strains of E. coli isolated from Black Sea were investigated for the expression of resistance to different bivalent metals (Cu, Co, Mn, Zn, Ni) compounds. The experiments were performed comparatively at different incubation temperatures (22°C, 37°C and 44°C) in aerobic and anaerobi...

  20. Antimicrobial susceptibility and genotyping analysis of Hungarian Neisseria gonorrhoeae strains in 2013.

    Science.gov (United States)

    Nemes-Nikodém, Éva; Brunner, Alexandra; Pintér, Dóra; Mihalik, Noémi; Lengyel, György; Marschalkó, Márta; Kárpáti, Sarolta; Szabó, Dóra; Ostorházi, Eszter

    2014-12-01

    Emergence and spread of antimicrobial resistance in Neisseria gonorrhoeae is a major public health concern worldwide. The current study aims to determine the antimicrobial resistance in N. gonorrhoeae and associated molecular typing to enhance gonococcal antimicrobial surveillance in Hungary. In the National N. gonorrhoeae Reference Laboratory of Hungary 187 N. gonorrhoeae infections were detected in 2013, antibiograms were determined for all the isolated strains, and 52 (one index strain from every sexually contact related group) of them were also analysed by the N. gonorrhoeae multi-antigen sequence typing (NG-MAST) method. Twenty-two different NG-MAST sequence types (STs) were identified, of which 8 STs had not been previously described. In Hungary, the highly diversified gonococcal population displayed high resistance to penicillin, ciprofloxacin and tetracycline (the antimicrobials previously recommended for gonorrhoea treatment). Resistance to the currently recommended extended spectrum cephalosporines were rare: only two of the expected strains, an ST 1407 and an ST 210, had cefixime MIC above the resistance breakpoint. By the revision of our National Treatment Guideline, it must be considered, that the azithromycin resistance is about 60% among the four most frequently isolated STs in Hungary.

  1. Susceptibility to ceftriaxone and occurrence of penicillinase plasmids in Neisseria gonorrhoeae strains isolated in Poland in 2012-2013.

    Science.gov (United States)

    Mlynarczyk-Bonikowska, Beata; Kujawa, Marlena; Mlynarczyk, Grazyna; Malejczyk, Magdalena; Majewski, Slawomir

    2016-07-01

    Recent years have seen rising concerns over increasing antibiotic resistance of the gonorrhea-causing bacterium, Neisseria gonorrhoeae. This is especially true for third-generation cephalosporins, which are currently recommended for the treatment of such infections. Therefore, susceptibility to these antibiotics should be monitored internationally to the greatest extent possible. The susceptibility of N. gonorrhoeae strains to ceftriaxone and penicillin, as well as production of beta-lactamase by the Cefinase test was determined. Moreover, the presence and type of penicillinase plasmids were determined by PCR. All strains were susceptible to ceftriaxone, the minimal inhibitory concentration (MIC) values ranged from 0.002 to 0.125 mg/L; MIC50 was =0.016 mg/L and MIC90 was =0.064 mg/L. As much as 7.7 % of the strains demonstrated ceftriaxone MIC of 0.125 mg/L. For penicillin, the MICs ranged from 0.064 to 32 mg/L; MIC50 was =0.5 mg/L and MIC90 was =4 mg/L. It was shown that only 1.5 % of the strains were sensitive to penicillin according to The European Committee on Antimicrobial Susceptibility Testing (EUCAST). Among the penicillin-resistant strains, six (30.0 %) produced penicillinase. The MICs of penicillin were substantially higher for penicillinase-producing than for penicillin-resistant, penicillinase-negative strains. MICs of ceftriaxone for penicillinase-producing strains were low (0.002-0.016 mg/L). Three of the penicillinase-producing strains possessed plasmids of African type (50 %) and three Toronto/Rio type (50 %). An increase of the proportion of beta-lactamase-positive strains in the last years as well as emergence of strains with elevated MIC of ceftriaxone indicate a need to constantly monitor N. gonorrhoeae strains for their susceptibility to beta-lactam antibiotics, as well as for their ability to produce beta-lactamases.

  2. The common ecotoxicology laboratory strain of Hyalella azteca is genetically distinct from most wild strains sampled in eastern North America.

    Science.gov (United States)

    Major, Kaley; Soucek, David J; Giordano, Rosanna; Wetzel, Mark J; Soto-Adames, Felipe

    2013-11-01

    The amphipod Hyalella azteca is commonly used as a model for determining safe concentrations of contaminants in freshwaters. The authors sequenced the mitochondrial cytochrome c oxidase subunit I (COI) gene for representatives of 38 populations of this species complex from US and Canadian toxicology research laboratories and eastern North American field sites to determine their genetic relationships. With 1 exception, all US and Canadian laboratory cultures sampled were identified as conspecific. In 22 wild populations spanning 5 US states and 1 Canadian province, the commonly occurring laboratory species was found only in northern Florida, USA. Therefore, the diversity of the H. azteca species complex detected in the wild is not accurately represented in North American laboratories, questioning the reliability of H. azteca cultures currently in use to accurately predict the responses of wild populations in ecotoxicological assays. The authors also examined the utility of different COI nucleotide fragments presently in use to determine phylogenetic relationships in this group and concluded that saturation in DNA sequences leads to inconsistent relationships between clades. Amino acid sequences for COI were not saturated and may allow a more accurate phylogeny estimate. Hyalella azteca is crucial for developing water-quality regulations; therefore, laboratories should know and standardize the strain(s) they use to confidently compare toxicity tests across laboratories and determine whether they are an appropriate surrogate for their regions. © 2013 SETAC.

  3. Progress in Antifungal Susceptibility Testing of Candida spp. by Use of Clinical and Laboratory Standards Institute Broth Microdilution Methods, 2010 to 2012

    Science.gov (United States)

    Pfaller, M. A.

    2012-01-01

    Antifungal susceptibility testing of Candida has been standardized and refined and now may play a useful role in managing Candida infections. Important new developments include validation of 24-h reading times for all antifungal agents and the establishment of species-specific epidemiological cutoff values (ECVs) for the systemically active antifungal agents and both common and uncommon species of Candida. The clinical breakpoints (CBPs) for fluconazole, voriconazole, and the echinocandins have been revised to provide species-specific interpretive criteria for the six most common species. The revised CBPs not only are predictive of clinical outcome but also provide a more sensitive means of identifying those strains with acquired or mutational resistance mechanisms. This brief review serves as an update on the new developments in the antifungal susceptibility testing of Candida spp. using Clinical and Laboratory Standards Institute (CLSI) broth microdilution (BMD) methods. PMID:22740712

  4. Growth temperature exerts differential physiological and transcriptional responses in laboratory and wine strains of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Pizarra, Francisco J.; Jewett, Michael Christopher; Nielsen, Jens

    2008-01-01

    Laboratory strains of Saccharomyces cerevisiae have been widely used as a model for studying eukaryotic cells and mapping the molecular mechanisms of many different human diseases. Industrial wine yeasts, on the other hand, have been selected on the basis of their adaptation to stringent...... global insight into how growth temperature affects differential physiological and transcriptional responses in laboratory and wine strains of S. cerevisiae....... environmental conditions and the organoleptic properties that they confer to wine. Here, we used a two-factor design to study the responses of a standard laboratory strain, CEN.PK113-7D, and an industrial wine yeast strain, EC1118, to growth temperatures of 15 degrees C and 30 degrees C in nitrogen...

  5. Summary report - development of laboratory tests and the stress- strain behaviour of Olkiluoto mica gneiss

    Energy Technology Data Exchange (ETDEWEB)

    Hakala, M.; Heikkilae, E. [Helsinki Univ. of Technology, Espoo (Finland). Lab. of Rock Engineering

    1997-05-01

    This work summarizes the project aimed at developing and qualifying a suitable combination of laboratory tests to establish a statistically reliable stress-strain behaviour of the main rock types at Posiva Oy`s detailed investigation sites for disposal of spent nuclear fuel. The work includes literature study of stress-strain behaviour of brittle rock, development and qualification of laboratory tests, suggested test procedures and interpretation methods and finally testing of Olkiluoto mica gneiss. The Olkiluoto study includes over 130 loading tests. Besides the commonly used laboratory tests, direct tensile tests, damage controlled tests and acoustic emission measurements were also carried out. (orig.) (54 refs.).

  6. Standardized broth microdilution antimicrobial susceptibility testing of Francisella tularensis subsp. holarctica strains from Europe and rare Francisella species.

    Science.gov (United States)

    Georgi, Enrico; Schacht, Erik; Scholz, Holger C; Splettstoesser, Wolf D

    2012-10-01

    Tularaemia is a widespread zoonosis in Europe caused by Francisella tularensis subsp. holarctica. Because of a lack of standardized CLSI-approved antibiotic susceptibility data from European Francisella strains, the antibiotic susceptibilities of a selection of F. tularensis subsp. holarctica isolates originating from Germany, Austria, France, Spain and other European countries were determined. Rarely isolated species and subspecies of Francisella such as Francisella philomiragia, F. tularensis subsp. novicida and F. tularensis subsp. mediasiatica as well as the type strain of Francisella hispaniensis were included in this study. MIC data were obtained using cation-adjusted Mueller-Hinton broth with a 2% growth supplement. The broth microdilution testing system comprised 14 antibiotics, including gentamicin, streptomycin, ciprofloxacin and tetracycline. All of the 91 strains tested were susceptible to aminoglycosides, quinolones, tetracycline and chloramphenicol. The antimicrobial susceptibility of rare Francisellae was similar to the antibiotic profile of F. tularensis subsp. holarctica strains. For erythromycin, we detected two geographically distinct groups of F. tularensis subsp. holarctica isolates in western Europe. One group was resistant and the other one was susceptible. Both groups overlapped in a small region in Germany. Being performed in accordance with CLSI criteria, this study provides reliable data on antibiotic susceptibility patterns of European Francisella isolates. The standardized methodology of this study can be used for testing of suspicious colonies from clinical specimens for therapeutic guidance. Based on the results, aminoglycosides or quinolones are recommended as first-choice antibiotics for the therapy of F. hispaniensis, F. philomiragia or F. tularensis subsp. novicida infections in immunocompromised patients.

  7. The Evaluation of the Distribution and Antimcrobial Susceptibility Profile of the Strains Isolated at Anesthesiology Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Gulfem Ece

    2013-10-01

    Full Text Available Aim: Hospital infections are important uptodate health problems because of high mortality and increased cost. The increment in antimicrobial resistance is progressing though new antimicrobial agents are arising. This leads to an increase in hospital infections and difficulty in treatment. In our study we aimed to evaluate the antimicrobial susceptibility of the strains isolated at Anesthesiology Intensive Care Unit. Material and Method: The antimicrobial susceptibility of the strains isolated at Anesthesiology Intensive Care Unit between April 1st 2012- October 25th 2012 were included. The identification and the antimicrobial susceptibility were studied by automatized Vitek version 2.0 (Biomerieux, France. Results: A total of 155 strains isolated from wound, blood, tracheal secretion, sputum and urine samples were included. They are consisted of 40 A. baumannii, 24 E.coli, 25 P. aeruginosa, 20 K.pneumoniae, 12 Methicilin Resistant Coagulase Negative Staphylococci (MRCoNS, nine Methiciline Susceptible S.aureus (MSSA, eight C.albicans, four Methicilin Resistant S.aureus (MRSA, one C.famata, one C.tropicalis, three E.faecalis, two E.faecium, three S.marsecens, two P. mirabilis and one H.influenzae. Clinical samples were 81 tracheal secretions, 25 wound specimen, 23 blood culture, 18 urine, seven sputum, and one BAL. All the Gram positive strains were susceptible to glycopeptides. Enterobacteriaceae members were susceptible to imipenem and meropenem. Discussion: Antimicrobial resistance is an important issue worldwide. Multidiciplinary approach is needed as in ICUs where the complicated patients are followed. Monitoring antibiotic resistance profile contributes to treatment and decreasing resistance rates. The resistance profile will guide the antibiotic use policy. Increment in number of isolates in future will help to obtain the antimicrobial resistance profile.

  8. Susceptibility of laboratory rats against genotypes 1, 3, 4, and rat hepatitis E viruses.

    Science.gov (United States)

    Li, Tian-Cheng; Yoshizaki, Sayaka; Ami, Yasushi; Suzaki, Yuriko; Yasuda, Shumpei P; Yoshimatsu, Kumiko; Arikawa, Jiro; Takeda, Naokazu; Wakita, Takaji

    2013-04-12

    To determine whether or not rats are susceptible to hepatitis E virus (HEV) infection, each of group containing three laboratory rats (Wistar) were experimentally inoculated with genotypes 1, 3, 4 and rat HEV by intravenous injection. Serum and stool samples were collected and used to detect HEV RNA and anti-HEV antibodies by RT-PCR and ELISA, respectively. The virus infection was monitored up to 3 months after inoculation. None of the serum or stool samples collected from the rats inoculated with G1, G3, or G4 HEV indicated positive sign for virus replication. Although no alteration was observed in ALT level, rat HEV RNA was detected in stools from both of the rats inoculated with rat HEV, and both rats were positive for anti-rat HEV IgG and IgM from 3 weeks after inoculation. These results demonstrated that rats are susceptible to rat HEV but not to G1, G3, and G4 HEV. We also confirm that the nude rats were useful for obtaining a large amount of rat HEV and that the rat HEV was transmitted by the fecal-oral route. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Evaluation of the pathogenic potential, antimicrobial susceptibility, and genomic relations of Yersinia enterocolitica strains from food and human origin.

    Science.gov (United States)

    Lucero-Estrada, Cecilia S M; Soria, José Miguel; Favier, Gabriela Isabel; Escudero, María Esther

    2015-11-01

    Yersinia enterocolitica is a food-borne pathogen that causes gastroenteritis with occasional postinfection sequels. This study was aimed to determinate the pathogenic potential, antimicrobial susceptibility, and genomic relationships of Y. enterocolitica strains of different bioserotypes (B/O) isolated from foods and human samples in San Luis, Argentina. Strains obtained by culture were bioserotyped and characterized by phenotypic and genotypic virulence markers, antimicrobial susceptibility, and pulsed-field gel electrophoresis (PFGE). Yersinia enterocolitica was detected in 9.2% of 380 samples, with a distribution of 10.6% (30/284) for food products and 5.2% (5/96) for human samples. Regarding the pathogenic potential, B1A strains of different serotypes were virF(-) ail(-), of which 72.0% (13/18) were ystB(+) with virulence-related phenotypic characteristics. Among B2/O:9 isolates, 75.0% (9/12) exhibited the genotype virF(+) ail(+) ystB(-) along with phenotypic traits associated with virulence; the same genotype was observed in 80.0% (4/5) of B3/O:3 and B3/O:5 strains. By PFGE, it was possible to separate Y. enterocolitica biotypes into 4 clonal groups (A to D) with 23 genomic types, generating a discriminatory index of 0.96. All isolates were susceptible to antimicrobials used for clinical treatment. This study highlights the presence of pathogenic bioserotypes and the high genomic diversity of the Y. enterocolitica strains isolated in our region.

  10. Global Phenotypic Characterization of Effects of Fluoroquinolone Resistance Selection on the Metabolic Activities and Drug Susceptibilities of Clostridium perfringens Strains

    Directory of Open Access Journals (Sweden)

    Miseon Park

    2014-01-01

    Full Text Available Fluoroquinolone resistance affects toxin production of Clostridium perfringens strains differently. To investigate the effect of fluoroquinolone resistance selection on global changes in metabolic activities and drug susceptibilities, four C. perfringens strains and their norfloxacin-, ciprofloxacin-, and gatifloxacin-resistant mutants were compared in nearly 2000 assays, using phenotype microarray plates. Variations among mutant strains resulting from resistance selection were observed in all aspects of metabolism. Carbon utilization, pH range, osmotic tolerance, and chemical sensitivity of resistant strains were affected differently in the resistant mutants depending on both the bacterial genotype and the fluoroquinolone to which the bacterium was resistant. The susceptibilities to gentamicin and erythromycin of all resistant mutants except one increased, but some resistant strains were less susceptible to amoxicillin, cefoxitin, ceftriaxone, chloramphenicol, and metronidazole than their wild types. Sensitivity to ethidium bromide decreased in some resistant mutants and increased in others. Microarray analysis of two gatifloxacin-resistant mutants showed changes in metabolic activities that were correlated with altered expression of various genes. Both the chemical structures of fluoroquinolones and the genomic makeup of the wild types influenced the changes found in resistant mutants, which may explain some inconsistent reports of the effects of therapeutic use of fluoroquinolones on clinical isolates of bacteria.

  11. The effects of myxobolus cerebralis on the physiological performance of whirling disease resistant and susceptible strains of rainbow trout

    Science.gov (United States)

    Fetherman, E.R.; Myrick, Christopher A.; Winkelman, D.L.; Schisler, G.J.

    2011-01-01

    The development of rainbow trout Oncorhynchus mykiss strains that are resistant to whirling disease has shown promise as amanagement tool for populationsin areas where Myxobolus cerebralisis present. However, the physiological effects of the disease on characteristics necessary for fish survival in natural river conditions have not been tested in many of these strains. Five rainbow trout strains were evaluated for their swimming ability and growth characteristics in relation to M. cerebralis exposure: the resistant German rainbow trout (GR) strain (Hofer strain), the susceptible Colorado River rainbow trout (CRR) strain, and three intermediate (hybrid) strains (F1 = GR ?? CRR; F2 = F1 ?? F1; B2 = backcross of F1 ?? CRR). Three broad response patterns among strain and exposure were evident in our study. First, exposure metrics, growth performance, and swimming ability differed among strains. Second, exposure to the parasite did not necessarily produce differences in growth or swimming ability. Exposure to M. cerebralis did not affect batch weight for any strain, and critical swimming velocity did not differ between exposed and unexposed families. Third, although exposure did not necessarily affect growth or swimming ability, individuals that exhibited clinical deformities did show reduced growth and swimming performance; fish with clinical deformities were significantly smaller and had lower critical swimming velocities than exposed fish without clinical deformities. Research and management have focused on GR ?? CRR hybrid strains; however, given the performance of the GR strain in our study, it should not be discounted as a potential broodstock. Additional field trials comparing the GR and F1 strains should be conducted before wholesale adoption of the GR strain to reestablish rainbow trout populations in Colorado. ?? American Fisheries Society 2011.

  12. Susceptibility trends of Bacteroides fragilis group and characterisation of carbapenemase-producing strains by automated REP-PCR and MALDI TOF.

    Science.gov (United States)

    Treviño, Mercedes; Areses, Paloma; Peñalver, M Dolores; Cortizo, Sandra; Pardo, Fernanda; del Molino, M Luisa Pérez; García-Riestra, Carlos; Hernández, Manuela; Llovo, José; Regueiro, Benito J

    2012-02-01

    Susceptibility testing of clinical isolates of anaerobic bacteria is not considered, often, mandatory in routine clinical practice and the treatments are empirically established. Thus, periodic monitoring of the susceptibility patterns of anaerobic bacteria is advisable. The aim of this study was to update on resistance of Bacteroides fragilis group in our Institution with special attention to carbapenems reporting metallo-beta-lactamase producing strains for the first time in Spain, and to compare fingerprinting analysis results obtained by using automated rep-PCR (DiversiLab System) and MALDI-TOF MS. A total of 830 non-duplicated clinical isolates of the B. fragilis group recovered from the years 2006 to 2010 were studied. B. fragilis was the most prevalent species (59.5%). The total susceptibility of B. fragilis group isolates were: penicillin, 13.3%; amoxicillin/clavulanic, 89.6%; piperacillin-tazobactam, 91.8%; cefoxitin, 65.8%; ertapenem, 95.9%; imipenem, 98.2%; clindamycin, 53.4% and metronidazole, 96.4%. The percentage of sensitive isolates did not change significantly over time for amoxicillin/clavulanic, cefoxitin, clindamycin and metronidazole. A slight increase in the rate of resistance to ertapenem and imipenem was observed. Imipenem resistance and carbapenemase production were detected for the first time in our laboratory in the year 2007. No other report of carbapenemase-producing B. fragilis in our country has been previously published. Six imipenem-resistant isolates were MBL-producing and PCR positive for cfiA gene. Four of them were PCR positive for IS-like immediately upstream cfiA gene and two of them were negative. Both, automated rep-PCR (DiversiLab) and MALDI-TOF MS, revealed a great genetic diversity among carbapenem-producing strains suggesting the acquisition of novel resistance genes more than clonal dissemination of them. Both methods seem to be useful tools for fast and accurate identification and strain typing of B. fragilis group in

  13. Genomic and physiological characterization of a laboratory-isolated Acinetobacter schindleri ACE strain that quickly and efficiently catabolizes acetate.

    Science.gov (United States)

    Sigala, Juan-Carlos; Suárez, Brisa Paola; Lara, Alvaro R; Borgne, Sylvie Le; Bustos, Patricia; Santamaría, Rosa Isela; González, Víctor; Martinez, Alfredo

    2017-07-01

    An Acinetobacter strain, designated ACE, was isolated in the laboratory. Phylogenetic tests and average nucleotide identity value comparisons suggested that ACE belongs to the species Acinetobacterschindleri. We report for the first time the complete genome sequence of an A. schindleri strain, which consists of a single circular chromosome of 3 001 209 bp with an overall DNA G+C content of 42.9 mol% and six plasmids that account for 266 844 bp of extrachromosomal material. The presence or absence of genes related to carbon catabolism and antibiotic resistance were in agreement with the phenotypic characterization of ACE. This strain grew faster and with a higher biomass yield on acetate than the reference strain Acinetobacter baylyi ADP1. However, ACE did not use aromatic compounds and was unable to grow on common carbon sources, such as glucose, xylose, glycerol or citrate. The gluconeogenic and the catechol pathways are complete in ACE, but compounds that are converted to protocatechuate did not sustain growth since some genes of this pathway are missing. Likewise, this strain could not grow on glucose because it lacks the genes of the Entner-Doudoroff pathway. Minimal inhibitory concentration data showed that ACE was susceptible to most of the antimicrobial agents recommended for the clinical treatment of Acinetobacter spp. Some genes related to a possible human-microbe interaction were found in the ACE genome. ACE is likely to have a low pathogenic risk, as is the case with other A. schindleri strains. These results provide a valuable reference for broadening the knowledge of the biology of Acinetobacter.

  14. Modeling the Endogenous Sunlight Inactivation Rates of Laboratory Strain and Wastewater E. coli and Enterococci Using Biological Weighting Functions.

    Science.gov (United States)

    Silverman, Andrea I; Nelson, Kara L

    2016-11-15

    Models that predict sunlight inactivation rates of bacteria are valuable tools for predicting the fate of pathogens in recreational waters and designing natural wastewater treatment systems to meet disinfection goals. We developed biological weighting function (BWF)-based numerical models to estimate the endogenous sunlight inactivation rates of E. coli and enterococci. BWF-based models allow the prediction of inactivation rates under a range of environmental conditions that shift the magnitude or spectral distribution of sunlight irradiance (e.g., different times, latitudes, water absorbances, depth). Separate models were developed for laboratory strain bacteria cultured in the laboratory and indigenous organisms concentrated directly from wastewater. Wastewater bacteria were found to be 5-7 times less susceptible to full-spectrum simulated sunlight than the laboratory bacteria, highlighting the importance of conducting experiments with bacteria sourced directly from wastewater. The inactivation rate models fit experimental data well and were successful in predicting the inactivation rates of wastewater E. coli and enterococci measured in clear marine water by researchers from a different laboratory. Additional research is recommended to develop strategies to account for the effects of elevated water pH on predicted inactivation rates.

  15. Serratia marcescens: Biochemical, Serological, and Epidemiological Characteristics and Antibiotic Susceptibility of Strains Isolated at Boston City Hospital

    Science.gov (United States)

    Wilfert, James N.; Barrett, Fred F.; Ewing, W. H.; Finland, Maxwell; Kass, Edward H.

    1970-01-01

    The biochemical, serological, and epidemiological characteristics of 95 strains of Serratia marcescens isolated at the Boston City Hospital were examined. Several strains were shown to be endemic, and the majority of isolates were cultured from urine or respiratory secretions. Serratia species were highly resistant to polymyxin B and the cephalosporins, and various proportions were also resistant to other antibiotics including kanamycin, but all of the isolates were sensitive to gentamicin. The appearance of resistance to kanamycin and nalidixic acid among endemic strains was demonstrated. The nosocomial nature of Serratia infections, particularly those involving the urinary tract, was confirmed. Many clinical bacteriology laboratories currently fail to identify the nonpigmented strains. PMID:4314379

  16. Modified alpha-amylase activity among insecticide-resistant and -susceptible strains of the maize weevil, Sitophilus zeamais.

    Science.gov (United States)

    Lopes, K V G; Silva, L B; Reis, A P; Oliveira, M G A; Guedes, R N C

    2010-09-01

    Fitness cost is usually associated with insecticide resistance and may be mitigated by increased energy accumulation and mobilization. Preliminary evidence in the maize weevil (Coleoptera: Curculionidae) suggested possible involvement of amylases in such phenomenon. Therefore, alpha-amylases were purified from an insecticide-susceptible and two insecticide-resistant strains (one with fitness cost [resistant cost strain], and the other without it [resistant no-cost strain]). The main alpha-amylase of each strain was purified by glycogen precipitation and ion-exchange chromatography (>or=70-fold purification, cost strain exhibited higher activity towards starch and lower inhibition by acarbose and wheat amylase inhibitors. Opposite results were observed for the alpha-amylase from the resistant cost strain. Although the alpha-amylase from the resistant cost strain exhibited higher affinity to starch (i.e., lower K(m)), its V(max)-value was the lowest among the strains, particularly the resistant no-cost strain. Such results provide support for the hypothesis that enhanced alpha-amylase activity may be playing a major role in mitigating fitness costs associated with insecticide resistance.

  17. Serogrupos y susceptibilidad antimicrobiana en cepas de Shigella Serogroups and antimicrobial susceptibility in Shigella strains

    Directory of Open Access Journals (Sweden)

    Leonor Díaz Rigau

    2009-03-01

    Full Text Available INTRODUCCIÓN. Shigella spp. es uno de los agentes causales más importantes de diarrea aguda en los niños. La presente investigación tuvo como objetivo conocer la frecuencia de serogrupos y la susceptibilidad antimicrobiana a los fármacos de elección y a los alternativos. MÉTODOS. Se realizó un estudio descriptivo y retrospectivo entre enero de 2004 y diciembre de 2006 a partir de 34 cepas de Shigella spp. aisladas en heces de niños menores de 5 años ingresados en el Hospital «Aleida Fernández Chardiet» (Municipio Güines a causa de enfermedad diarreica aguda. RESULTADOS. Los serogrupos encontrados fueron S. sonnei (70,5 % y S. flexneri (29,5 %. Ambos serogrupos mostraron altos niveles de resistencia al trimetoprim-sulfametoxazol y a la ampicilina, además en las cepas de S. sonnei se encontró resistencia al ácido nalidíxico y en las de S. flexneri al cloranfenicol. Todas las cepas mostraron altos porcentajes de sensibilidad a la ceftriaxona, norfloxacina y ciprofloxacina. El 70 % de las cepas de S. sonnei fueron multirresistentes. El patrón de multirresistencia (ampicilina, trimetoprim-sulfamtetoxazol y ácido nalidíxico se encontró en ambos serogrupos. CONCLUSIONES. La determinación y vigilancia de los patrones de resistencia facilita el control de la política de uso de antibióticos en la región estudiada y previene el surgimiento de cepas resistentes a fármacos de nueva generación.INTRODUCTION: Shigella ssp. is one of the more important causal agents of acute diarrhea in children. Present research has as aim to know serogroups frequency and antimicrobial susceptibility to choice drugs, and to its alternatives. METHODS: A descriptive retrospective study was carried out between January 2004 and December 2006 of 34 strains of Shigella isolated from children lower than 5 years admitted in "Aleida Fernández Chardiet" Hospital in Güines Municipality by acute diarrheic disease. RESULTS: Serogroups included S. sonnei (70

  18. Reverberation Chamber Uniformity Validation and Radiated Susceptibility Test Procedures for the NASA High Intensity Radiated Fields Laboratory

    Science.gov (United States)

    Koppen, Sandra V.; Nguyen, Truong X.; Mielnik, John J.

    2010-01-01

    The NASA Langley Research Center's High Intensity Radiated Fields Laboratory has developed a capability based on the RTCA/DO-160F Section 20 guidelines for radiated electromagnetic susceptibility testing in reverberation chambers. Phase 1 of the test procedure utilizes mode-tuned stirrer techniques and E-field probe measurements to validate chamber uniformity, determines chamber loading effects, and defines a radiated susceptibility test process. The test procedure is segmented into numbered operations that are largely software controlled. This document is intended as a laboratory test reference and includes diagrams of test setups, equipment lists, as well as test results and analysis. Phase 2 of development is discussed.

  19. cDNAs of aminopeptidase-like protein genes from Plodia interpunctella strains with different susceptibilities to Bacillus thuringiensis toxins.

    Science.gov (United States)

    Zhu, Y C; Kramer, K J; Oppert, B; Dowdy, A K

    2000-03-01

    Aminopeptidase N has been reported to be a Bacillus thuringiensis (Bt) Cry1A toxin-binding protein in several lepidopteran insects. cDNAs of aminopeptidase-like proteins from both Bt-susceptible RC688s and Bt-resistant HD198r strains of the Indianmeal moth, Plodia interpunctella, were cloned and sequenced. They contain 3345 and 3358 nucleotides, respectively, and each has a 3048 bp open reading frame that encodes 1016 amino acids. Putative protein sequences include 10 potential glycosylation sites and a zinc metal binding site motif of HEXXH, which is typical of the active site of zinc-dependent metallopeptidases. Sequence analysis indicated that the deduced protein sequences are most similar to an aminopeptidase from Heliothis virescens with 62% sequence identity and highly similar to three other lepidopteran aminopeptidases from Plutella xylostella, Manduca sexta, Bombyx mori with sequence identities of 51-52%. Four nucleotide differences were observed in the open reading frames that translated into two amino acid differences in the putative protein sequences. Polymerase chain reaction (PCR) confirmed an aminopeptidase gene coding difference between RC688s and HD198r strains of P. interpunctella in the PCR amplification of a specific allele (PASA) using preferential primers designed from a single base substitution. The gene mutation for Asp185-->Glu185 was also confirmed in two additional Bt-resistant P. interpunctella strains. This mutation is located within a region homologous to the conserved Cry1Aa toxin binding regions from Bombyx mori and Plutella xylostella. The aminopeptidase-like mRNA expression levels in the Bt-resistant strain were slightly higher than those in the Bt-susceptible strain. The sequences reported in this paper have been deposited in the GenBank database (accession numbers AF034483 for susceptible strain RC688s and AF034484 for resistant strain HD198r).

  20. Effect of different lateral occlusion schemes on peri-implant strain: A laboratory study

    Science.gov (United States)

    Lo, Jennifer; Palamara, Joseph

    2017-01-01

    PURPOSE This study aims to investigate the effects of four different lateral occlusion schemes and different excursions on peri-implant strains of a maxillary canine implant. MATERIALS AND METHODS Four metal crowns with different occlusion schemes were attached to an implant in the maxillary canine region of a resin model. The included schemes were canine-guided (CG) occlusion, group function (GF) occlusion, long centric (LC) occlusion, and implant-protected (IP) occlusion. Each crown was loaded in three sites that correspond to maximal intercuspation (MI), 1 mm excursion, and 2 mm excursion. A load of 140 N was applied on each site and was repeated 10 times. The peri-implant strain was recorded by a rosette strain gauge that was attached on the resin model buccal to the implant. For each loading condition, the maximum shear strain value was calculated. RESULTS The different schemes and excursive positions had impact on the peri-implant strains. At MI and 1 mm positions, the GF had the least strains, followed by IP, CG, and LC. At 2 mm, the least strains were associated with GF, followed by CG, LC, and IP. However, regardless of the occlusion scheme, as the excursion increases, a linear increase of peri-implant strains was detected. CONCLUSION The peri-implant strain is susceptible to occlusal factors. The eccentric location appears to be more influential on peri-implant strains than the occlusion scheme. Therefore, adopting an occlusion scheme that can reduce the occurrence of occlusal contacts laterally may be beneficial in reducing peri-implant strains. PMID:28243391

  1. Effect of different lateral occlusion schemes on peri-implant strain: A laboratory study.

    Science.gov (United States)

    Lo, Jennifer; Abduo, Jaafar; Palamara, Joseph

    2017-02-01

    This study aims to investigate the effects of four different lateral occlusion schemes and different excursions on peri-implant strains of a maxillary canine implant. Four metal crowns with different occlusion schemes were attached to an implant in the maxillary canine region of a resin model. The included schemes were canine-guided (CG) occlusion, group function (GF) occlusion, long centric (LC) occlusion, and implant-protected (IP) occlusion. Each crown was loaded in three sites that correspond to maximal intercuspation (MI), 1 mm excursion, and 2 mm excursion. A load of 140 N was applied on each site and was repeated 10 times. The peri-implant strain was recorded by a rosette strain gauge that was attached on the resin model buccal to the implant. For each loading condition, the maximum shear strain value was calculated. The different schemes and excursive positions had impact on the peri-implant strains. At MI and 1 mm positions, the GF had the least strains, followed by IP, CG, and LC. At 2 mm, the least strains were associated with GF, followed by CG, LC, and IP. However, regardless of the occlusion scheme, as the excursion increases, a linear increase of peri-implant strains was detected. The peri-implant strain is susceptible to occlusal factors. The eccentric location appears to be more influential on peri-implant strains than the occlusion scheme. Therefore, adopting an occlusion scheme that can reduce the occurrence of occlusal contacts laterally may be beneficial in reducing peri-implant strains.

  2. Laboratory-Cultured Strains of the Sea Anemone Exaiptasia Reveal Distinct Bacterial Communities

    KAUST Repository

    Herrera Sarrias, Marcela

    2017-05-02

    Exaiptasia is a laboratory sea anemone model system for stony corals. Two clonal strains are commonly used, referred to as H2 and CC7, that originate from two genetically distinct lineages and that differ in their Symbiodinium specificity. However, little is known about their other microbial associations. Here, we examined and compared the taxonomic composition of the bacterial assemblages of these two symbiotic Exaiptasia strains, both of which have been cultured in the laboratory long-term under identical conditions. We found distinct bacterial microbiota for each strain, indicating the presence of host-specific microbial consortia. Putative differences in the bacterial functional profiles (i.e., enrichment and depletion of various metabolic processes) based on taxonomic inference were also detected, further suggesting functional differences of the microbiomes associated with these lineages. Our study contributes to the current knowledge of the Exaiptasia holobiont by comparing the bacterial diversity of two commonly used strains as models for coral research.

  3. Laboratory tests in the detection of extended spectrum beta-lactamase production: National Committee for Clinical Laboratory Standards (NCCLS screening test, the E-test, the double disk confirmatory test, and cefoxitin susceptibility testing

    Directory of Open Access Journals (Sweden)

    Pedro A. d'Azevedo

    Full Text Available Extended spectrum beta-lactamase (ESBL production by Klebsiella sp. and E. coli is an emerging problem. In this study, 107 clinical isolates (53 E. coli, 47 K. pneumoniae and 7 K. oxytoca screened as ESBL producers by the NCCLS disk diffusion procedure were submitted to a double disk confirmatory test (DDT and to the E-test double strip for confirmation of ESBL production by demonstration of clavulanic acid inhibition effect (CAIE. Only 72/107 (67% of the isolates were confirmed as ESBL producers by DDT, with diverse results among species. By the E-test, 58/107 (54% isolates were confirmed as ESBL producers, and 18/107 (17% were not determinable. Susceptibility to cefoxitin was found in 57/68 (83% of strains that did not show CAIE. ESBL detection remains a controversial issue and clinical laboratories are in need of a simple and effective way to recognize strains with this kind of resistance.

  4. Genetic basis of differences in myxospore count between whirling disease-resistant and -susceptible strains of rainbow trout

    Science.gov (United States)

    Fetherman, Eric R.; Winkelman, Dana L.; Schisler, George J.; Antolin, Michael F.

    2012-01-01

    We used a quantitative genetics approach and estimated broad sense heritability (h2b) of myxospore count and the number of genes involved in myxospore formation to gain a better understanding of how resistance to Myxobolus cerebralis, the parasite responsible for whirling disease, is inherited in rainbow trout Oncorhynchus mykiss. An M. cerebralis-resistant strain of rainbow trout, the German Rainbow (GR), and a wild, susceptible strain of rainbow trout, the Colorado River Rainbow (CRR), were spawned to create 3 intermediate crossed populations (an F1 cross, F2 intercross, and a B2 backcross between the F1 and the CRR). Within each strain or cross, h2b was estimated from the between-family variance of myxospore counts using full-sibling families. Estimates of h2b and average myxospore counts were lowest in the GR strain, F1 cross, and F2 intercross (h2b = 0.34, 0.42, and 0.34; myxospores fish−1 = 275, 9566, and 45780, respectively), and highest in the B2 backcross and CRR strain (h2b = 0.93 and 0.89; myxospores fish−1 = 97865 and 187595, respectively). Comparison of means and a joint-scaling test suggest that resistance alleles arising from the GR strain are dominant to susceptible alleles from the CRR strain. Resistance was retained in the intermediate crosses but decreased as filial generation number increased (F2) or backcrossing occurred (B2). The estimated number of segregating loci responsible for differences in myxospore count in the parental strains was 9 ± 5. Our results indicate that resistance to M. cerebralis is a heritable trait within these populations and would respond to either artificial selection in hatcheries or natural selection in the wild.

  5. Specific mutations of penicillin-binding protein 1A in 77 clinically acquired amoxicillin-resistant Helicobacter pylori strains in comparison with 77 amoxicillin-susceptible strains.

    Science.gov (United States)

    Kwon, Yong Hwan; Kim, Ji Yeon; Kim, Nayoung; Park, Ji Hyun; Nam, Ryoung Hee; Lee, Sun Min; Kim, Jin-Wook; Kim, Jung Mogg; Park, Jong Youn; Lee, Dong Ho

    2017-08-25

    Amoxicillin (Amx) is one of the most important antibiotics for eradication of Helicobacter pylori (H. pylori). Main determinants of genetically stable Amx resistance are mutations in the C-terminus of penicillin-binding protein 1A (pbp1A). However, contribution of individual mutation remains unclear. 77 Amx-resistant (Amx(R) ) and 77 Amx-susceptible (Amx(S) ) H. pylori strains were isolated from gastric tissues, and DNA sequencing was performed to compare C-terminus sequences of pbp1A gene between Amx(R) and Amx(S) strains. Natural transformation of these mutated genes into amoxicillin-susceptible strains was performed. Among many mutations in pbp1A, D479E (OR: 37.4, 95% CI: 5.53-252.49, P < .001), and T593 mutation (OR: 32.0, 95% CI: 4.04-252.86, P < .001) independently contributed to Amx resistance in H. pylori strains. In the transformation experiment, T593 mutations were identified in their transformants showing Amx resistance. However, PCR product of D479E was not inserted into recipient (ATCC 43504) resulting in transformation failure. Amx resistance is associated with various substitutions in pbp1A and T593 mutation contributes to Amx resistance of H. pylori. © 2017 John Wiley & Sons Ltd.

  6. Susceptibility of Two European strains of Stomoxys calcitrans (L.) to Cypermethrin, Deltamethrin, Fenvalerate, lambda-cyhalothrin, Permethrin and Phoxim

    OpenAIRE

    Salem, Ali; Bouhsira, Emilie; Lienard, Emmanuel; Bousquet, Alain; Jacquiet, Philippe; Franc, Michel

    2012-01-01

    Susceptibility of two French strains of stable flies Stomoxys calcitrans (L.) to six insecticides was assayed, using an exposure technique (1-hour contact) with treated filter papers. Three replicates per insecticide, per concentration (10 concentrations per insecticide), per fly strain (ENVT, Cabanac) and fly category (blood-engorged - non-blood-engorged) were performed using a total of 14,400 adult flies in this trial. The LD50 and LD90 are higher for the blood-engorged flies than the non-b...

  7. Screening probiotic strains for safety: Evaluation of virulence and antimicrobial susceptibility of enterococci from healthy Chinese infants.

    Science.gov (United States)

    Zhang, Fen; Jiang, Meiling; Wan, Cuixiang; Chen, Xiaoyan; Chen, Xiaoyong; Tao, Xueying; Shah, Nagendra P; Wei, Hua

    2016-06-01

    The aim of this study was to evaluate the safety of enterococci isolated from Chinese infants and screen out potential probiotic candidates. One hundred eight strains were isolated from feces of 34 healthy infants, and 38 strains of Enterococcus spp. were categorized as follows: E. faecalis (22), E. faecium (10), E. hirae (3), E. durans (2), and E. casseliflavus (1). Of these, 72.7% of E. faecalis came from infants delivered by cesarean and 62.5% of E. faecium from infants delivered vaginally. For safety evaluation of strains, we determined presence of virulence genes; production of hemolysin, gelatinase, and biofilm; and antimicrobial susceptibility of enterococci. Six out of 14 virulence genes were detected with a distribution of gelE (26.3%), cylA (39.4%), esp (15.8%), efaA (63.2%), asa1 (50.0%), and ace (50.0%). In phenotype analysis, 36.8% of the strains exhibited positive hemolytic activity and 17.5% were positive for production of gelatinase. Results of antimicrobial susceptibility showed that different percentages of the strains were resistant to ciprofloxacin (5.2%), vancomycin (7.8%), rifampicin (10.5%), erythromycin (52.6%), and gentamycin (52.6%); remarkably, none of the strains were resistant to ampicillin or chloramphenicol. In total, 10 strains, including 6 E. faecium, which are free of virulence determinants and sensitive to common antimicrobial agents (e.g., ampicillin and vancomycin), were further assessed for their probiotic properties. All strains survived well in simulated gastric fluid and intestinal tract, with maximum reductions of 0.600 and 0.887 log cfu/mL, respectively. Six strains of E. faecium could resist 0.3 to 1.0% bile salt, of which E. faecium WEFA23 presented the highest growth (75.06%) at 1.0% bile salt. All strains showed bile salt hydrolase activity on glycodeoxycholic acid, but only 3 of E. faecium showed activity on taurodeoxycholic acid. These results deliver useful information on the safety of enterococci in infants in

  8. Detection of an ABCA1 Variant Associated with Type 2 Diabetes Mellitus Susceptibility for Biochemistry and Genetic Laboratory Courses

    Science.gov (United States)

    Legorreta-Herrera, M.; Mosqueda-Romo, N. A.; Hernández-Clemente, F.; Soto-Cruz, I.

    2013-01-01

    We selected diabetes mellitus for this laboratory exercise to provide students with an explicit model for scientific research concerning the association between the R230C polymorphism and susceptibility to type 2 diabetes mellitus, which is highly prevalent in the Mexican population. We used a collaborative project-based learning to engage…

  9. Field prevalence and laboratory susceptibility of southern Australian land snails to Brachylaima cribbi sporocyst infection

    Directory of Open Access Journals (Sweden)

    Butcher A.R.

    2003-06-01

    Full Text Available Brachylaima cribbi is a terrestrial trematode of birds and mammals with helic id and hygromild land snails reported as first and second Intermediate hosts. However, reports describing the first Intermediate host range of B. cribbi have been limited to those snail species present In a small number of geographical locations In South Australia. The natural first Intermediate host range, distribution and prevalence of B. cribbi In land snails In southern Australia were determined. A total of 6,432 introduced and native land snails were collected from eight geographical districts across 3,000 km of southern Australia and examined microscopically for B. cribbi sporocysts. Four Introduced European snails, Theba pisana, Cernuella virgata, Cochlicella acuta and Cochlicella barbara were natural first Intermediate hosts. Sporocyst-infected snails were detected In all districts from Victoria to the west coast of South Australia, a distance of over 1,300 km. Natural sporocyst infection was not observed in introduced European snails Microxeromagna armillata and Helix aspersa or In native Australian land snails Succinea australis and Strangesta gawleri. Egg feeding experiments in the laboratory with B. cribbi confirmed the susceptibility of those species of snails found to be natural first intermediate hosts. Of those species not found to be Infected In nature, only M. armillata could be Infected In the laboratory. Although this study has shown that five different species of European land snails are suitable first Intermediate hosts for B. cribbi there are as yet no reports of B. cribbi from these snails In Europe or from other countries where they have been introduced. Further Investigations are needed in Europe to clarify the origins of this parasite.

  10. A survey of methods used for antimicrobial susceptibility testing in veterinary diagnostic laboratories in the United States.

    Science.gov (United States)

    Dargatz, David A; Erdman, Matthew M; Harris, Beth

    2017-09-01

    Antimicrobial resistance is a serious threat to animal and human health worldwide, requiring a collaborative, holistic approach. The U.S. Government has developed a national strategy to address antimicrobial resistance, with one component being to monitor antimicrobial resistance in agricultural settings. We developed a survey to collect information about antimicrobial susceptibility testing (AST) from the veterinary diagnostic laboratory community in the United States, assessing current practices and technologies and determining how AST information is shared. Of the 132 surveys administered, 52 (39%) were returned. Overall, responding laboratories conducted susceptibility tests on 98,788 bacterial isolates in 2014, with Escherichia coli being the most common pathogen tested across all animal species. The 2 most common AST methods employed were the disk diffusion method (71%) and the Sensititre platform broth microdilution system (59%). Laboratories primarily used the Clinical Laboratory Standards Institute (CLSI) VET-01 standard (69%) and the automatically calculated interpretations provided by the commercial AST systems (61%) for interpreting their AST data. Only 22% of laboratories published AST data on a periodic basis, usually via annual reports published on the laboratory's website or through peer-reviewed journals for specific pathogens. Our results confirm that disk diffusion and broth microdilution remain the standard AST methods employed by U.S. veterinary diagnostic laboratories, and that CLSI standards are commonly used for interpreting AST results. This information will help determine the most efficient standardized methodology for future surveillance. Furthermore, the current infrastructure within laboratories, once harmonized, will help provide a mechanism for conducting national surveillance programs.

  11. Characterization of Neisseria gonorrhoeae Strains with Decreased Susceptibility to Fluoroquinolones Isolated in Greece from 1996 to 1999

    Science.gov (United States)

    Mavroidi, Angeliki; Tzouvelekis, Leonidas S.; Tassios, Panayotis T.; Flemetakis, Alexandros; Daniilidou, Maria; Tzelepi, Eva

    2000-01-01

    Of the 331 Neisseria gonorrhoeae strains isolated in Greece from 1996 to 1999, 39 (11.8%) exhibited decreased susceptibility to quinolones due to gyrA and parC mutations. Conventional typing and pulsed-field gel electrophoresis showed that 34 of these isolates were clonally related. Epidemiological data indicated that the epidemic clone was sustained in a group of high-frequency transmitters. PMID:10970412

  12. Studies on the susceptibility of ostriches (Struthio camelus) to the Indonesian velogenic strain of Newcastle disease virus

    OpenAIRE

    Darminto; Sjamsul Bahri

    1998-01-01

    Susceptibility of ostriches (Struthio camelus) to the Indonesian velogenic strain of Newcastle disease virus (NDV) was evaluated by artificial infection . Twelve - 5 to 6 week old ostriches were divided into 3 groups each containing 4 birds . The first group was inoculated through respiratory system by dropping directly the virus solution into the nostrils, while the second group was inoculated through digestive system by dropping directly the virus solution into the oesophagus, with the dose...

  13. The role of Intelectin-2 in resistance to Ascaris suum lung larval burdens in susceptible and resistant mouse strains.

    Science.gov (United States)

    Dold, Christina; Pemberton, Alan D; Stafford, Peter; Holland, Celia V; Behnke, Jerzy M

    2011-04-01

    The underlying mechanism of predisposition to Ascaris infection is not yet understood but host genetics are thought to play a fundamental role. We investigated the association between the Intelectin-2 gene and resistance in F2 mice derived from mouse strains known to be susceptible and resistant to infection. Ascaris larvae were isolated from murine lungs and the number of copies of the Intelectin-2 gene was determined in F2 mice. Intelectin-2 gene copy number was not significantly linked to larval burden. In a pilot experiment, the response to infection in parental mice of both sexes was observed in order to address the suitability of female F2 mice. No overall significant sex effect was detected. However, a divergence in resistance/susceptibility status was observed between male and, female hybrid offspring. The responsiveness to Ascaris in mice is likely to be controlled by multiple genes and, despite a unique absence from the susceptible C57BL/6j strain, the Intelectin-2 gene does not play a significant role in resistance. The observed intra-strain variation in larval burden requires further investigation but we hypothesize that it stems from social/dominance hierarchies created by the presence of female mice and possibly subsequent hormonal perturbations that modify the intensity of the immune response.

  14. Susceptibility of inbred mouse strains to infection with three species of Metagonimus prevalent in the Republic of Korea.

    Science.gov (United States)

    Guk, Sang-Mee; Park, Jin-Young; Seo, Min; Han, Eun-Taek; Kim, Jae-Lip; Chai, Jong-Yil

    2005-02-01

    Susceptibility of inbred mouse strains to Metagonimus yokogawai, Metagonimus miyatai, and Metagonimus takahashii infections was studied using BALB/c, ddY, C57BL/6J, C3H/HeN, and A/J mice, with H-2 haplotypes d, s, b, k, and a, respectively. Two hundred metacercariae were orally fed to each mouse, and the worm recovery rates (WRR), worm dimensions, and intrauterine egg numbers were measured at days 3, 7, 14, 21, and 28 postinfection (PI). On day 14 PI, the WRR of M. yokogawai was highest in ddY mice (average, 62.2%); those of M. miyatai and M. takahashii were highest in ddY (19.5%) and BALB/c mice (10.4%), respectively; worm maturation was best in C3H/HeN (M. yokogawai), C57BL/6J (M. miyatai), and ddY mice (M. takahashii). All mouse strains showed higher susceptibility to infection with M. yokogawai than with M. miyatai or M. takahashii. The results show that susceptibility of mice to Metagonimus infection varies according to mouse strain and parasite species but is suggested to be independent of the mouse H-2 haplotype.

  15. Efficient single nucleotide polymorphism discovery in laboratory rat strains using wild rat-derived SNP candidates

    NARCIS (Netherlands)

    Smits, B.M.; Guryev, V.; Zeegers, D.; Wedekind, D.; Hedrich, H.J.; Cuppen, E.

    2005-01-01

    BACKGROUND: The laboratory rat (Rattus norvegicus) is an important model for studying many aspects of human health and disease. Detailed knowledge on genetic variation between strains is important from a biomedical, particularly pharmacogenetic point of view and useful for marker selection for

  16. ASTM E-2369 TMF: Inter Laboratory Study (ILS) on Strain Controlled Thermo-Mechanical Fatigue Testing

    OpenAIRE

    RIPPLINGER Stefan; HAEHNER Peter; BRUCHHAUSEN MATTHIAS; DE HAAN Fredericus; AUSTIN TIMOTHY

    2016-01-01

    The document presents the results of the tests conducted at the JRC Petten site, under the frame of the Inter Laboratory Study (ILS) on Thermomechanical Fatigue (ASTM E-2368). The primary purpose of this study is to provide a precision and bias statement to be included in the revision of ASTM E-2368, Standard Practice for Strain Controlled Thermo-Mechanical Fatigue Testing.

  17. COMPARISON OF MATING AND BITING BEHAVIOR IN TWO LABORATORY STRAINS OF ANOPHELES QUADRIMACULATUS SAY

    Science.gov (United States)

    IN ORDER TO ASSEMBLE SOME EVIDENCE OF POSSIBLE PHYSIOLOGICAL DIFFERENCES WHICH MIGHT HAVE DEVELOPED AMONG LABORATORY STRAINS OF Anopheles ... quadrimaculatus Say, and which might lead to biological segregation, a colony from Wilson Dam, Alabama, was compared in detail with another from Bethesda

  18. Effect of a standardised dietary restriction protocol on multiple laboratory strains of Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Richard C Grandison

    Full Text Available Outcomes of lifespan studies in model organisms are particularly susceptible to variations in technical procedures. This is especially true of dietary restriction, which is implemented in many different ways among laboratories.In this study, we have examined the effect of laboratory stock maintenance, genotype differences and microbial infection on the ability of dietary restriction (DR to extend life in the fruit fly Drosophila melanogaster. None of these factors block the DR effect.These data lend support to the idea that nutrient restriction genuinely extends lifespan in flies, and that any mechanistic discoveries made with this model are of potential relevance to the determinants of lifespan in other organisms.

  19. Development Of An Efficient Glycerol Utilizing Saccharomyces Cerevisiae Strain Via Adaptive Laboratory Evolution

    DEFF Research Database (Denmark)

    Strucko, Tomas; Zirngibl, Katharina; Tharwat Tolba Mohamed, Elsayed

    2015-01-01

    fermentation processes. The most commonly known microbial cell factory, the yeast Saccharomyces cerevisiae, has been extensively applied for the production of a wide range of scientifically and industrially relevant products using saccharides (mainly glucose) as carbon source. However, it was shown...... that popular wild-type laboratory yeast strains, commonly applied in metabolic engineering studies, did not grow or grew very slowly in glycerol medium.In this work, an adaptive laboratory evolution approach to obtain S. cerevisiae strains with an improved ability to grow on glycerol was applied. A broad array...... catabolism in yeast. The knowledge acquired in this study may be further applied for rational S. cerevisiae strain improvement for using glycerol as a carbon source in industrial biotechnology processes. This work is a part of the DeYeastLibrary consortium financed by ERA-IB DeYeastLibrary - Designer yeast...

  20. Genetic analysis and cross-resistance spectrum of a laboratory-selected chlorfenapyr resistant strain of two-spotted spider mite (Acari: Tetranychidae).

    Science.gov (United States)

    Van Leeuwen, Thomas; Stillatus, Vincent; Tirry, Luc

    2004-01-01

    A laboratory susceptible strain of Tetranychus urticae was selected with chlorfenapyr resulting in a resistant strain. After 12 cycles of exposure, the resistance ratio (RR) calculated from the LC50s of susceptible and selected strain was 580. The resistant strain was screened with 16 currently used acaricides for cross-resistance. Cross-resistance was detected with amitraz (RR = 19.1), bifenthrin (RR = 1.3), bromopropylate (RR = 7.5), clofentezine (RR = 29.6) and dimethoate (RR = 17.6). No cross-resistance was detected with the new molecules acequinocyl, bifenazate and spirodiclofen. Mortality caused by chlorfenapyr in the F1 progeny from reciprocal crosses between both strains indicated that the mode of inheritance was incomplete recessive. Mortality in F2 progeny indicated that the resistance was under the control of more than one gene. Synergist experiments with S,S,S-tributylphosphorotrithioate (DEF), piperonylbutoxide (PBO) and diethylmaleate (DEM), which are inhibitors of esterases, monooxygenases and glutathion-S-transferases respectively, suggested a major role of esterases in the resistance to chlorfenapyr.

  1. Carbapenem non-susceptible enterobacteriaceae in Quebec, Canada: results of a laboratory surveillance program (2010-2012.

    Directory of Open Access Journals (Sweden)

    Brigitte Lefebvre

    Full Text Available The emergence and spread of carbapenemase-producing Enterobacteriaceae (CPE represent a major public health concern because these bacteria are usually extensively resistant to most antibiotics. In order to evaluate their dissemination in Quebec, a surveillance program was introduced in 2010. We report the molecular and epidemiological profiles of CPE isolates collected. Between August 2010 and December 2012, a total of 742 non-duplicate isolates non-susceptible to carbapenems were analysed. AmpC β-lactamase and metallo-β-lactamase production were detected by Etest and carbapenemase production by the modified Hodge test (MHT. Antibiotic susceptibility profiles were determined using broth microdilution or Etest. Clonality of Klebsiella pneumoniae carbapenemase (KPC strains was analyzed by pulsed-field gel electrophoresis (PFGE. The presence of genes encoding carbapenemases as well as other β-lactamases was detected using PCR. Of the 742 isolates tested, 169 (22.8% were CPE. Of these 169 isolates, 151 (89.3% harboured a blaKPC gene while the remaining isolates carried blaSME (n = 9, blaOXA-48 (n = 5, blaNDM (n = 3, and blaNMC (n = 1 genes. Among the 93 KPC strains presenting with a unique pattern (unique PFGE pattern and/or unique antibiotics susceptibility profile, 99% were resistant to ertapenem, 95% to imipenem, 87% to meropenem, 97% to aztreonam, 31% to colistin and 2% to tigecycline. In 19 patients, 2 to 5 KPC strains from different species or with a different PFGE pattern were isolated. CPE strains were present in the province of Quebec with the majority of strains harbouring KPC. Alternately, SME, OXA-48 and NMC containing strains were rarely found.

  2. Miltefosine-resistant Leishmania infantum strains with an impaired MT/ROS3 transporter complex retain amphotericin B susceptibility.

    Science.gov (United States)

    Mondelaers, Annelies; Hendrickx, Sarah; Van Bockstal, Lieselotte; Maes, Louis; Caljon, Guy

    2018-02-01

    Increasing numbers of miltefosine treatment failures in visceral leishmaniasis therapy and reports of miltefosine resistance in the Indian subcontinent resulted in the recommendation to use liposomal amphotericin B as first-line therapy. Cross-resistance between miltefosine and amphotericin B has recently been documented, suggesting a role of mutations in the miltefosine transporter, a complex encoded by the MT and ROS3 genes. This study aimed to further explore the putative role of MT/ROS3 defects in the molecular basis of amphotericin B cross-resistance. The susceptibility profiles of different miltefosine-resistant Leishmania infantum strains with well-characterized mutations in the transporter complex and the corresponding episomally restored susceptible parasite lines were determined using both the routine extracellular promastigote assay and the intracellular amastigote assay. In vitro amastigote and promastigote susceptibility testing of the two miltefosine-resistant and the episomally reconstituted L. infantum lines revealed full susceptibility to amphotericin B, despite the variable miltefosine susceptibility profile. Mutations present in either the MT and/or ROS3 gene are not sufficient to elicit higher tolerance to amphotericin B. Additional synergistic adaptations may be responsible for the miltefosine/amphotericin B cross-resistance described earlier.

  3. Molecular characterization and antimicrobial susceptibility of Pasteurella multocida strains isolated from hosts affected by various diseases in Italy.

    Science.gov (United States)

    Cucco, Lucilla; Massacci, Francesca Romana; Sebastiani, Carla; Mangili, Piermario; Bano, Luca; Cocchi, Monia; Luppi, Andrea; Ortenzi, Roberta; Pezzotti, Giovanni; Magistrali, Chiara Francesca

    2017-03-31

    Pasteurella multocida is a widespread pathogen associated with major animal diseases of economic significance. Despite this, little is known about the capsular types, virulence gene pattern, and antimicrobial susceptibility of isolates from hosts affected by different diseases, and no data are available in Italy. One hundred eighty six isolates of P. multocida, were taken from different species in different states of health in several Italian regions, and were tested for genes encoding for capsular types (cap) and major virulence factors (tbpA, toxA, hgbB and pfhA). Antimicrobial susceptibility was investigated with the agar diffusion test. The majority of isolates was capA+. However, the distribution differed according to species and disease of origin, with a greater heterogeneity in isolates from rabbits; capE was never found, while capB was detected once. Only capA+ and capF+ strains tested positive for pfhA. Conversely, almost all capD+ isolates were hgbB+. In bovine respiratory disease, pfhA+/tbpA+/capA+ isolates predominated, while tbpA+/toxA+/capD+ isolates predominated in sheep. Overall, low levels of resistance were found, with full susceptibility to ceftiofur and florfenicol. Lower susceptibility to older antimicrobials was recorded, since only approximately 1/3 of the isolates showed susceptibility to tylosin and erythromycin, and resistance to tetracycline (7.5%), and trimethoprim - sulphametoxazole (4.8%) was also observed.

  4. Characterization of Shigella Strains by Plasmid Profile Analysis and Antibiotic Susceptibility Patterns in a Pediatric Hospital in Ahvaz

    Directory of Open Access Journals (Sweden)

    Amin Sakhaei

    2015-11-01

    Full Text Available Background: High incidences of dysentery and diarrhea were reported in a pediatric hospital in Ahvaz, Iran during March to April, 2013. Objectives: A cross-sectional study was therefore undertaken to identify the causative agents. Patients and Methods: A total of 230 diarrhea samples were collected from the patients and analyzed by routine bacteriological methods. Bacterial identification, serological assay, antimicrobial susceptibility testing, extended spectrum β-lactamases (ESBLs screening and plasmid profile analysis were performed according to the standard guidelines. Results: A total of 70 Shigella strains including %70 (n = 49 S. sonnei and 30% (n = 21 S. flexneri were isolated from diarrhea samples. Most of the Shigella isolates showed high degrees of resistance to ampicillin, ulafamethoxazole- trimethoprime and cefexim. Concurrent resistance to sulafametoxazole- trimethoprime and ampicillin was the most common resistance pattern. Overall, 11.4% of Shigella isolates showed the ESBL producer criteria. The plasmid profile patterns of all the strains were determined by a modified alkaline lysis method. By plasmid profile analysis 23 genotypes were identified among all the isolates, 14 and 9 genotypes among the S. sonnei and S. Flexneri respectively. S. sonnei and S. flexneri isolates demonstrated unique plasmid profiles. Conclusions: These data demonstrated that S. sonnei strains are the main cause of shigellosis as the prevalent Shigella serotype in Iran. We also found that the antibiotic resistance rates are increasing among Shigella strains. Plasmid profile analysis is more reliable than antibiotic susceptibility patterns in epidemiologic studies.

  5. Reduced maximal inhibition in phenotypic susceptibility assays indicates that viral strains resistant to the CCR5 antagonist maraviroc utilize inhibitor-bound receptor for entry.

    Science.gov (United States)

    Westby, Mike; Smith-Burchnell, Caroline; Mori, Julie; Lewis, Marilyn; Mosley, Michael; Stockdale, Mark; Dorr, Patrick; Ciaramella, Giuseppe; Perros, Manos

    2007-03-01

    Maraviroc is a CCR5 antagonist in clinical development as one of a new class of antiretrovirals targeting human immunodeficiency virus type 1 (HIV-1) coreceptor binding. We investigated the mechanism of HIV resistance to maraviroc by using in vitro sequential passage and site-directed mutagenesis. Serial passage through increasing maraviroc concentrations failed to select maraviroc-resistant variants from some laboratory-adapted and clinical isolates of HIV-1. However, high-level resistance to maraviroc was selected from three of six primary isolates passaged in peripheral blood lymphocytes (PBL). The SF162 strain acquired resistance to maraviroc in both treated and control cultures; all resistant variants were able to use CXCR4 as a coreceptor. In contrast, maraviroc-resistant virus derived from isolates CC1/85 and RU570 remained CCR5 tropic, as evidenced by susceptibility to the CCR5 antagonist SCH-C, resistance to the CXCR4 antagonist AMD3100, and an inability to replicate in CCR5 Delta32/Delta32 PBL. Strain-specific mutations were identified in the V3 loop of maraviroc-resistant CC1/85 and RU570. The envelope-encoding region of maraviroc-resistant CC1/85 was inserted into an NL4-3 background. This recombinant virus was completely resistant to maraviroc but retained susceptibility to aplaviroc. Reverse mutation of gp120 residues 316 and 323 in the V3 loop (numbering from HXB2) to their original sequence restored wild-type susceptibility to maraviroc, while reversion of either mutation resulted in a partially sensitive virus with reduced maximal inhibition (plateau). The plateaus are consistent with the virus having acquired the ability to utilize maraviroc-bound receptor for entry. This hypothesis was further corroborated by the observation that a high concentration of maraviroc blocks the activity of aplaviroc against maraviroc-resistant virus.

  6. Cell lines from grc congenic strains of rats having different susceptibilities to chemical carcinogens.

    Science.gov (United States)

    Lu, D; Kunz, H W; Melhem, M F; Gill, T J

    1993-09-01

    The growth and reproduction complex (grc-) strains of rats have a 70-kilobase deletion in the major histocompatibility complex (MHC)-linked grc-G/C region that is associated with embryonic death, developmental defects, and an increased susceptibility to chemical carcinogens. To study further the effects associated with the deletion, fibroblastic cell lines from grc-, grc+, and grc+/- rat embryos were developed: BIL-derived cell lines are congenic for the MHC and grc, whereas R16-derived cell lines are congenic for the grc alone. In early passages, all cell lines expressed the MHC class I antigen RT1.A, had a diploid chromosome number, and did not display anchorage-independent growth or in vivo tumorigenicity. The grc- cells [median population doubling time (PDT), 47 h] grew more slowly than the grc+ (PDT, 30.5 h) and grc+/- (PDT, 33 h) cells. All cells underwent crisis, but the crisis stage began earlier and lasted longer in the grc- cells. The established grc- cell lines (PDT, 32.5 h) grew faster than the grc+ (PDT, 48.5 h) and grc+/- (PDT, 54 h) cell lines. Two of the three BIL-derived grc- lines that survived crisis became anchorage independent in tissue culture and tumorigenic in histocompatible F1 rats (highly malignant fibrosarcomas) at passages 33 and 48, respectively; by contrast, none of the R16-derived grc- cell lines transformed. None of 8 grc+ or 8 grc+/- cell lines that survived crisis displayed anchorage-independent growth or tumorigenicity under the same conditions up to passage 50. All of the established cell lines, including the two tumorigenic ones, expressed MHC class I antigens. Southern and Northern blot analyses of BIL-derived cell lines before and after crisis showed that they all constitutively expressed H-ras and Rb and that no cell line showed rearrangement, amplification, or overexpression of c-myc, H-ras, Rb, and p53 either before or after crisis. These observations indicate that: (a) the homozygous grc- deletion is necessary but not

  7. Antibiotic susceptibility of coagulase-negative staphylococci (CoNS): emergence of teicoplanin-non-susceptible CoNS strains with inducible resistance to vancomycin.

    Science.gov (United States)

    Ma, Xiao Xue; Wang, En Hua; Liu, Yong; Luo, En Jie

    2011-11-01

    Coagulase-negative staphylococci (CoNS) have become increasingly recognized as important agents of nosocomial infection. One of the characteristics of CoNS is their resistance to multiple antimicrobial agents commonly used for the treatment of staphylococcal infections. CoNS strains (n = 745) isolated from a university teaching hospital in China between 2004 and 2009 were tested for antibiotic resistance. The antibiotics were placed into three categories based on resistance levels of the CoNS strains to these antibiotics: high resistance (resistance rate >70 %), including penicillin G, oxacillin and erythromycin; medium resistance (resistance rate between 30 and 70 %), including tetracycline, clindamycin, ciprofloxacin, trimethoprim/sulfamethoxazole and chloramphenicol; and low resistance (resistance rate teicoplanin increased from 4.5 to 6.7 % between 2008 and 2009. A one-step vancomycin agar selection experiment and subsequent population analysis revealed potentially vancomycin-resistant subpopulations that have been selected from the teicoplanin-non-susceptible strains. Vigilant surveillance of nosocomial isolates of CoNS is needed to determine their resistance to glycopeptides.

  8. Isolation, Identification and Antimicrobial Susceptibility Pattern of Tatumella ptyseos Strains Isolated From Powdered Infant Formula Milk Consumed in Neonatal Intensive Care Unit: First Report From Iran

    Science.gov (United States)

    Mardaneh, Jalal; Soltan Dallal, Mohammad Mehdi; Taheripoor, Mehrnaz; Rajabi, Zahra

    2014-01-01

    Background: Tatumella ptyseos is a rod-shaped, Gram-negative, facultative, and anaerobic bacteria categorized in the Enterobacteriaceae family. It is a rare food-borne opportunistic pathogen which causes neonatal sepsis, bacteremia, and urinary tract infections. T. ptyseos has been also cultured from various food sources around the world. Objectives: It is difficult to determine the source of the infection in the patients (especially newborns) due to low information about the epidemiology of T. ptyseos. The current study aimed to investigate the isolation, identification and antimicrobial susceptibility pattern of T. ptyseos strains from the consumed powdered infant formula milk (PIF) in hospital neonatal intensive care unit (NICU). Materials and Methods: A total of 125 powdered infant formula milk (PIF) samples were purchased from drug stores from June 2011 to March 2012. T. ptyseos was isolated according to food and drug administration (FDA) method. For final confirmation, biochemical testes embedded in API-20E system were used. Drug susceptibility test was performed using the disc diffusion method, according to clinical and laboratory standard institute (CLSI) recommendations. Results: Results of the study showed that, out of 125 samples, T. ptyseos was isolated from four (3/2%) PIF samples. All isolated strains (100%) were resistant to ampicillin, carbenicillin, cotrimoxazole and amoxicillin. Conclusions: The present study was the first report on the isolation and identification of T. ptyseos from PIF in Iran. T. ptyseos are frequently present in various kinds of foods; therefore, further investigation on these samples is required. It is necessary to track the T. ptyseos in a wide variety of foods and individuals especially in immunocompromised people such as human immunodeficiency virus (HIV)-positive patients to reveal the possible routes of transmission of this pathogen to humans. In addition, molecular studies are required to determine the genetic

  9. In vitro drug susceptibility of two strains of the wildlife trypanosome, Trypanosoma copemani: A comparison with Trypanosoma cruzi.

    Science.gov (United States)

    Botero, Adriana; Keatley, Sarah; Peacock, Christopher; Thompson, R C Andrew

    2017-04-01

    Trypanosomes are blood protozoan parasites that are capable of producing illness in the vertebrate host. Within Australia, several native Trypanosoma species have been described infecting wildlife. However, only Trypanosoma copemani has been associated with pathological lesions in wildlife hosts and more recently has been associated with the drastic decline of the critically endangered woylie (Bettongia penicillata). The impact that some trypanosomes have on the health of the vertebrate host has led to the development of numerous drug compounds that could inhibit the growth or kill the parasite. This study investigated and compared the in vitro susceptibility of two strains of T. copemani (G1 and G2) and one strain of Trypanosoma cruzi (10R26) against drugs that are known to show trypanocidal activity (benznidazole, posaconazole, miltefosine and melarsoprol) and against four lead compounds, two fenarimols and two pyridine derivatives (EPL-BS1937, EPL-BS2391, EPL-BS0967, and EPL-BS1246), that have been developed primarily against T.cruzi. The in vitro cytotoxicity of all drugs against L6 rat myoblast cells was also assessed. Results showed that both strains of T. copemani were more susceptible to all drugs and lead compounds than T. cruzi, with all IC50 values in the low and sub-μM range for both species. Melarsoprol and miltefosine exhibited the highest drug activity against both T. copemani and T. cruzi, but they also showed the highest toxicity in L6 cells. Interestingly, both fenarimol and pyridine derivative compounds were more active against T. copemani and T. cruzi than the reference drugs benznidazole and posaconazole. T. copemani strains exhibited differences in susceptibility to all drugs demonstrating once again considerable differences in their biological behaviour. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Susceptibility of Aedes albopictus and Aedes aegypti to three imported Chikungunya virus strains, including the E1/226V variant in Taiwan.

    Science.gov (United States)

    Chen, Tien-Huang; Jian, Shu-Wan; Wang, Chih-Yuan; Lin, Cheo; Wang, Pei-Feng; Su, Chien-Ling; Teng, Hwa-Jen; Shu, Pei-Yun; Wu, Ho-Sheng

    2015-06-01

    An E1/226V variant Chikungunya virus (CHIKV) efficiently transmitted by Aedes albopictus to humans poses a significant threat to public health for those areas with the presence of Aedes albopictus, including Taiwan. We infected three imported CHIKV isolates including the E1/226V variant with Ae. albopictus and Aedes aegypti in the laboratory to understand the disease risk. Viral RNA was measured by real time reverse transcription polymerase chain reaction. The viral susceptibility varied by virus strain and mosquito species and strain. The Asian virus strain started to replicate at 5-6 days post infection (dpi) with the maximum virus yield, ranging from 10(3.63) to 10(3.87) at 5-10 dpi in both species. The variant CHIKV Central/East/South African (CESA) virus genotype replicated earlier at 1 dpi with the maximum virus yield ranging from 10(5.63) to 10(6.52) at 3-6 dpi in Ae. albopictus females while the nonvariant virus strain replicated at 1-2 dpi with the maximum virus yield ranging from 10(5.51) to 10(6.27) at 6-12 dpi. In Ae. aegypti, these viruses replicated at 1-2 dpi, with maximum yields at 4-5 dpi (range from 10(5.38) to 10(5.62)). We concluded that the risk of CHIKV in Taiwan is high in all distribution areas of Ae. aegypti and Ae. albopictus for the CESA genotype and that the E1/226V variant virus strain presents an even higher risk. Copyright © 2015. Published by Elsevier B.V.

  11. Genetic susceptibility of the arterial wall is an important determinant of atherosclerosis in C57BL/6 and FVB/N mouse strains

    DEFF Research Database (Denmark)

    Shim, Jeong; Handberg, Aase; Östergren, Eva-Britt Caroline

    2011-01-01

    How genetic variations among inbred mouse strains translate into differences in atherosclerosis susceptibility is of significant interest for the development of new therapeutic strategies. The objective of the present study was to examine whether genetically controlled arterial wall properties in...

  12. What is the mechanism for persistent coexistence of drug-susceptible and drug-resistant strains of Streptococcus pneumoniae?

    Science.gov (United States)

    Colijn, Caroline; Cohen, Ted; Fraser, Christophe; Hanage, William; Goldstein, Edward; Givon-Lavi, Noga; Dagan, Ron; Lipsitch, Marc

    2010-01-01

    The rise of antimicrobial resistance in many pathogens presents a major challenge to the treatment and control of infectious diseases. Furthermore, the observation that drug-resistant strains have risen to substantial prevalence but have not replaced drug-susceptible strains despite continuing (and even growing) selective pressure by antimicrobial use presents an important problem for those who study the dynamics of infectious diseases. While simple competition models predict the exclusion of one strain in favour of whichever is ‘fitter’, or has a higher reproduction number, we argue that in the case of Streptococcus pneumoniae there has been persistent coexistence of drug-sensitive and drug-resistant strains, with neither approaching 100 per cent prevalence. We have previously proposed that models seeking to understand the origins of coexistence should not incorporate implicit mechanisms that build in stable coexistence ‘for free’. Here, we construct a series of such ‘structurally neutral’ models that incorporate various features of bacterial spread and host heterogeneity that have been proposed as mechanisms that may promote coexistence. We ask to what extent coexistence is a typical outcome in each. We find that while coexistence is possible in each of the models we consider, it is relatively rare, with two exceptions: (i) allowing simultaneous dual transmission of sensitive and resistant strains lets coexistence become a typical outcome, as does (ii) modelling each strain as competing more strongly with itself than with the other strain, i.e. self-immunity greater than cross-immunity. We conclude that while treatment and contact heterogeneity can promote coexistence to some extent, the in-host interactions between strains, particularly the interplay between coinfection, multiple infection and immunity, play a crucial role in the long-term population dynamics of pathogens with drug resistance. PMID:19940002

  13. Molecular characterization and antifungal susceptibility of Cryptococcus neoformans strains collected from a single institution in Lima, Peru.

    Science.gov (United States)

    Bejar, Vilma; Tello, Mercedes; García, Ruth; Guevara, José M; Gonzales, Sofia; Vergaray, German; Valencia, Esther; Abanto, Enma; Ortega-Loayza, Alex G; Hagen, Ferry; Gutierrez, Ericson L

    2015-01-01

    Cryptococcosis is a fungal infection with a worldwide distribution, mainly caused by Cryptococcus neoformans and Cryptococcus gattii. To molecularly characterize the mating-types, serotypes, genotypes and antifungal susceptibility profiles of a set of retrospectively isolated C. neoformans strains from Lima, Peru. A set of 32 Cryptococcus spp. strains from the Institute of Tropical Medicine of the National University of San Marcos, Lima, Peru, were included in this retrospective study. Twenty-four strains were isolated from patients, while the remaining 8 were isolated from the environment. Using conventional PCR, 27 (84.4%) of the isolates were identified as C. neoformans var. grubii mating-type alpha and serotype A. Using the AFLP fingerprinting, it was shown that 16 (50%) of the C. neoformans strains were genotype AFLP1, 13 (40.6%) were genotype AFLP1B, 2 (6.3%) were genotype AFLP2, and 1 (3.1%) was found to be a hybrid between both C. neoformans varieties (genotype AFLP3). The antifungal susceptibility profiles for amphotericin B, fluconazole and voriconazole showed that all the 32 C. neoformans are sensitive to these antifungal compounds. In this study we observed that C. neoformans var. grubii (AFLP1 and AFLP1B) and C. neoformans var. neoformans (AFLP2) were the only cryptococcal varieties involved. All strains were found to be sensitive to the antifungals tested, results that are consistent with those found in the international literature. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  14. Identification and determination of antibiotic susceptibilities of Brucella strains isolated from patients in van, Turkey by conventional and molecular methods.

    Science.gov (United States)

    Parlak, Mehmet; Güdücüoğlu, Hüseyin; Bayram, Yasemin; Çıkman, Aytekin; Aypak, Cenk; Kılıç, Selçuk; Berktaş, Mustafa

    2013-01-01

    Brucellosis is a worldwide zoonotic disease and still constitutes a major public health problem. In this study, we aimed to identify biovars of Brucella strains isolated from clinical specimens taken from brucellosis patients from the Eastern Anatolia region as well determine the susceptibility of these isolates to tigecycline and azithromycin, drugs that may serve as alternatives to the conventional drugs used in the therapy. Seventy-five Brucella spp. isolates were included in the study. All strains were identified by both conventional and molecular methods. Brucella Multiplex PCR kit (FC-Biotech, Code: 0301, Turkey) and B. melitensis biovar typing PCR kit (FC-Biotech, Code: 0302, Turkey) were used for molecular typing. Antimicrobial susceptibilities of all strains were determined by E-tests. By conventional biotyping, 73 strains were identified as B. melitensis biovar 3 and two strains as B. abortus biovar 3. Molecular typing results were compatible with conventional methods. The MIC50 and MIC90 values of doxycycline were 0.047 and 0.094; tigecycline 0.094 and 0.125; trimethoprim/sulfamethoxazole 0.064 and 0.19; ciprofloxacin 0.19 for both; streptomycin 0.75 and 1; rifampin 1 and 2 and azithromycin 4 and 8. According to the MIC values, doxycycline was found to be the most effective antibiotic, followed by tigecycline, trimethoprim-sulfamethoxazole and ciprofloxacin. Currently recommended antibiotics for the treatment of brucellosis such as doxycycline, rifampin, streptomycin, trimethoprim-sulfamethoxazole and ciprofloxacin were found to be still effective. While our results showed that tigecycline can be used an alternative agent in the treatment of brucellosis, azithromycin has not been confirmed as an appropriate agent for the treatment.

  15. Anisotropy of magnetic susceptibility in diamagnetic limestones reveals deflection of the strain field near the Dead Sea Fault, northern Israel

    Science.gov (United States)

    Issachar, R.; Levi, T.; Marco, S.; Weinberger, R.

    2015-08-01

    To exploit the potential of anisotropy of magnetic susceptibility (AMS) as a tool to estimate the strain field around major faults, we measured the AMS of calcite-bearing diamagnetic rocks that crop out next to the Dead Sea Fault (DSF) in northern Israel. Through integrated magnetic and geochemical methods we found that the rocks are almost pure calcite rocks and therefore the magnetic fabric is primarily controlled by preferred crystallographic orientation (PCO) with the minimum principal AMS axes (k3) parallel to calcite c-axes. We applied a separation procedure in several samples with high Fe content in order to calculate the AMS anisotropy parameters and compare them to pure diamagnetic rocks. AARM, thermo-susceptibility curves and IRM were used to characterize the magnetic phases. We found that for Fe content below 500 ppm the AMS is mostly controlled by the diamagnetic phase and showed that differences in the degree of anisotropy P' up to 3% (P' = 1.005 to 1.023) and in anisotropy difference Δk (up to ~ 0.25 × 10- 6 SI) in diamagnetic rocks are related to differences of strain magnitudes. The spatial distribution of the magnetic fabrics indicates ~ N-S maximum shortening parallel to the strike of the Hula Western Border fault (HWBF), one of the main strands of the DSF in northern Israel. The anisotropy parameters suggest that the strain magnitudes increase eastward with the proximity to the HWBF. These results suggest that the strain field near the HWBF is locally deflected as a consequence of the DSF activity. In light of the "fault weakness" model and geological setting of the study area, we suggest that the area accommodates dominant transtension during the Pleistocene. The present study demonstrates the useful application of AMS measurements in "iron-free" limestones as recorders of the strain field near plate boundaries.

  16. Antibiotic susceptibility of 33 Prevotella strains isolated from Romanian patients with abscesses in head and neck spaces.

    Science.gov (United States)

    Bancescu, Gabriela; Didilescu, Andreea; Bancescu, Adrian; Bari, Maria

    2015-10-01

    The purpose of this study was to investigate the susceptibility of a series of 33 Prevotella strains isolated from patients with abscesses in the head and neck spaces, presented to one Romanian hospital. The Etest was applied to determine the value of the minimum inhibitory concentrations for: penicillin G, ampicillin, amoxicillin-clavulanate, metronidazole and clindamycin. In addition, the beta-lactamase activity was detected by the chromogenic cephalosporin disc method. The results indicated that 11 isolates were resistant to both penicillin G and ampicillin due to the beta-lactamase production. All the 33 Prevotella strains were susceptible to the other 3 antimicrobial agents tested, except for only one penicillin G - ampicillin resistant isolate of Prevotella buccae (MIC > 32 and MIC = 12 mg/L, respectively), which showed high resistance to clindamycin (MIC > 256 mg/L) too. Our data underline the necessity for antimicrobial testing including monitoring of beta-lactamase production in cases of oro-maxillo-facial mixed anaerobic infections where antimicrobial treatment is required in addition to the surgical drainage. The results of the study indicated that amoxicillin-clavulanate, like metronidazole, was fully active against the tested Prevotella strains. However, local and multicentre surveys on drug resistance among the clinically significant anaerobic isolates should be carried out periodically. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Natural antimicrobial susceptibility patterns of Kluyvera ascorbata and Kluyvera cryocrescens strains and review of the clinical efficacy of antimicrobial agents used for the treatment of Kluyvera infections.

    Science.gov (United States)

    Stock, I

    2005-04-01

    The natural susceptibility of 58 K. ascorbata and 24 K. cryocrescens strains to 71 antimicrobial agents was investigated. MIC values were determined with a microdilution procedure in cation-adjusted Mueller Hinton broth (for all strains) and IsoSensitest broth (for some strains). Both species were naturally sensitive or of intermediate susceptibility to tetracyclines, aminoglycosides, quinolones, antifolates, chloramphenicol, nitrofurantoin, fosfomycin, aminopenicillins plus beta-lactamase inhibitors, acylureidopenicillins, carbapenems, aztreonam and some cephalosporins. Uniform natural resistance was found with several macrolides, lincosamides, streptogramins, glycopeptides, rifampicin, fusidic acid, linezolid, penicillin G, oxacillin, and amoxicillin. To the latter agent, some strains of both species were also of intermediate susceptibility. Species-related differences in natural susceptibility affecting clinical assessment criteria were seen with azithromycin, cethromycin, telithromycin, ticarcillin and some cephalosporins, to which K. ascorbata was less susceptible than K. cryocrescens. Medium-related differences in susceptibility were restricted to a few antibiotics. A data base about the natural susceptibility of the two most common Kluyvera spp. to a wide range of antimicrobial agents is presented. It can be used for the validation of forthcoming susceptibility trials of these microorganisms. Although some susceptibilty patterns might be helpful for the phenotypical separation of K. ascorbata from K. cryocrescens, they do not allow a separation of these species. The literature dealing with the clinical efficacy of antimicrobial agents used for the treatment of Kluyvera infections is discussed.

  18. RNA-Seq Analyses for Two Silkworm Strains Reveals Insight into Their Susceptibility and Resistance to Beauveria bassiana Infection

    Directory of Open Access Journals (Sweden)

    Dongxu Xing

    2017-02-01

    Full Text Available The silkworm Bombyx mori is an economically important species. White muscardine caused by Beauveria bassiana is the main fungal disease in sericulture, and understanding the silkworm responses to B. bassiana infection is of particular interest. Herein, we investigated the molecular mechanisms underlying these responses in two silkworm strains Haoyue (HY, sensitive to B. bassiana and Kang 8 (K8, resistant to B. bassiana using an RNA-seq approach. For each strain, three biological replicates for immersion treatment, two replicates for injection treatment and three untreated controls were collected to generate 16 libraries for sequencing. Differentially expressed genes (DEGs between treated samples and untreated controls, and between the two silkworm strains, were identified. DEGs and the enriched Kyoto Encyclopedia of Genes and Genomes (KEGG pathways of the two strains exhibited an obvious difference. Several genes encoding cuticle proteins, serine proteinase inhibitors (SPI and antimicrobial peptides (AMP and the drug metabolism pathway involved in toxin detoxification were considered to be related to the resistance of K8 to B. bassiana. These results revealed insight into the resistance and susceptibility of two silkworm strains against B. bassiana infection and provided a roadmap for silkworm molecular breeding to enhance its resistance to B. bassiana.

  19. RNA-Seq Analyses for Two Silkworm Strains Reveals Insight into Their Susceptibility and Resistance to Beauveria bassiana Infection.

    Science.gov (United States)

    Xing, Dongxu; Yang, Qiong; Jiang, Liang; Li, Qingrong; Xiao, Yang; Ye, Mingqiang; Xia, Qingyou

    2017-02-10

    The silkworm Bombyx mori is an economically important species. White muscardine caused by Beauveria bassiana is the main fungal disease in sericulture, and understanding the silkworm responses to B. bassiana infection is of particular interest. Herein, we investigated the molecular mechanisms underlying these responses in two silkworm strains Haoyue (HY, sensitive to B. bassiana) and Kang 8 (K8, resistant to B. bassiana) using an RNA-seq approach. For each strain, three biological replicates for immersion treatment, two replicates for injection treatment and three untreated controls were collected to generate 16 libraries for sequencing. Differentially expressed genes (DEGs) between treated samples and untreated controls, and between the two silkworm strains, were identified. DEGs and the enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the two strains exhibited an obvious difference. Several genes encoding cuticle proteins, serine proteinase inhibitors (SPI) and antimicrobial peptides (AMP) and the drug metabolism pathway involved in toxin detoxification were considered to be related to the resistance of K8 to B. bassiana. These results revealed insight into the resistance and susceptibility of two silkworm strains against B. bassiana infection and provided a roadmap for silkworm molecular breeding to enhance its resistance to B. bassiana.

  20. Multidrug resistant Acinetobacter baumannii: risk factors for appearance of imipenem resistant strains on patients formerly with susceptible strains.

    Directory of Open Access Journals (Sweden)

    Jung-Jr Ye

    Full Text Available BACKGROUND: Multidrug resistant Acinetobacter baumannii (MDRAB is an important nosocomial pathogen usually susceptible to carbapenems; however, growing number of imipenem resistant MDRAB (IR-MDRAB poses further clinical challenge. The study was designed to identify the risk factors for appearance of IR-MDRAB on patients formerly with imipenem susceptible MDRAB (IS-MDRAB and the impact on clinical outcomes. METHODOLOGY/PRINCIPAL FINDINGS: A retrospective case control study was carried out for 209 consecutive episodes of IS-MDRAB infection or colonization from August 2001 to March 2005. Forty-nine (23.4% episodes with succeeding clinical isolates of IR-MDRAB were defined as the cases and 160 (76.6% with all subsequent clinical isolates of IS-MDRAB were defined as the controls. Quantified antimicrobial selective pressure, "time at risk", severity of illness, comorbidity, and demographic data were incorporated for multivariate analysis, which revealed imipenem or meropenem as the only significant independent risk factor for the appearance of IR-MDRAB (adjusted OR, 1.18; 95% CI, 1.09 to 1.27. With selected cases and controls matched to exclude exogenous source of IR-MDRAB, multivariate analysis still identified carbapenem as the only independent risk factor (adjusted OR, 1.48; 95% CI, 1.14 to 1.92. Case patients had a higher crude mortality rate compared to control patients (57.1% vs. 31.3%, p = 0.001, and the mortality of case patients was associated with shorter duration of "time at risk", i.e., faster appearance of IR-MDRAB (adjusted OR, 0.9; 95% CI, 0.83 to 0.98. CONCLUSIONS/SIGNIFICANCE: Judicious use of carbapenem with deployment of antibiotics stewardship measures is critical for reducing IR-MDRAB and the associated unfavorable outcome.

  1. Typing of Streptococcus mutans strains isolated from caries free and susceptible subjects by multilocus enzyme electrophoresis

    OpenAIRE

    Tahmourespour, Arezoo; Nabinejad, Abdolreza; Shirian, Hannaneh; Rosa, Edvaldo Antonio Ribeiro; Tahmourespour, Sanaz

    2013-01-01

    This study was evaluated the clonal diversity of Streptococcus mutans in caries-free and caries-active subjects using MLEE. Strains from caries-free subjects were grouped in a single taxon. Unrooted dendrogram showed that different strains clustered in four different clades, also showed that more than one clonal type can be found in a same individual.

  2. Susceptibilities of beta-lactamase-producing and -nonproducing ampicillin-resistant strains of Haemophilus influenzae to ceftibuten, cefaclor, cefuroxime, cefixime, cefotaxime, and amoxicillin-clavulanic acid.

    Science.gov (United States)

    Barry, A L; Fuchs, P C; Pfaller, M A

    1993-01-01

    In in vitro studies we evaluated the susceptibilities of beta-lactamase-producing and -nonproducing, ampicillin-resistant strains of Haemophilus influenzae and compared them with those of ampicillin-susceptible strains. Ampicillin, amoxicillin-clavulanic acid, ceftibuten, cefaclor, cefuroxime, cefixime, and cefotaxime were evaluated by broth microdilution tests and disk diffusion tests. The disk diffusion tests accurately categorized beta-lactamase-producing strains and ampicillin-susceptible strains as being susceptible to the study drugs other than ampicillin. Ampicillin-resistant, beta-lactamase-nonproducing strains were relatively resistant to all seven study drugs, but the disk diffusion test did not always predict that resistance. The clinical relevance of the decreased susceptibility to various agents remains unclear, but to be conservative, all ampicillin-resistant, beta-lactamase-nonproducing strains might be assumed to be resistant to other beta-lactams. After excluding that small group of isolates, reliable susceptibility test results were obtained with lots of Haemophilus Test Medium that met quality assurance criteria. PMID:8431012

  3. Antimicrobial susceptibility testing of Escherichia coli strains isolated from urinary tract infections to fluoroquinolones and detection of gyrA mutations in resistant strains

    Directory of Open Access Journals (Sweden)

    Akbari-Nakhjavani F.

    2007-05-01

    Full Text Available Widespread uses of fluoroquinolones have resulted in increasing incidences of resistance against these agents all over the world. The aim of this study was to assess, susceptibility of Escherichia coli strains from patients with Urinary Tract Infection against common fluoroquinolones and detection of mutations in the gyrA gene. Antimicrobial susceptibility testing of 164 E.coli isolates from patients with UTI, was evaluated by disk agar diffusion (DAD and MIC methods. Polymerase chain reaction of E.coli strains were performed by amplification of Quinolone Resistance Determining Region (QRDR of gyrA gene. PCR products were tested by Conformational Sensitive Gel Electrophoresis (CSGE and those with hetrodublexes were selected and examined by DNA sequencing. According to disc agar diffusion, 49.3% were resistant to nalidixic acid, 41.4% to norfloxacin, 44.5% to ofloxacin and 40.2 % to ciprofloxacin. By Minimal Inhibitory Concentration (MIC testing a high-level of resistance (42.1% to ciprofloxacin was observed. Mutations in codons 83 and 87 in all 81 isolates were positive by CSGE method.

  4. Comparative susceptibility of bemisia tabaci to imidacloprid in field- and laboratory-based bioassays

    Science.gov (United States)

    Bemisia tabaci biotype B is a resistance-prone pest of protected and open agriculture. Systemic uptake bioassays used in resistance monitoring programs have provided important information on susceptibility to neonicotinoid insecticides, but have remained decoupled from field performance. Simultaneou...

  5. Standard practice for slow strain rate testing to evaluate the susceptibility of metallic materials to environmentally assisted cracking

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This practice covers procedures for the design, preparation, and use of axially loaded, tension test specimens and fatigue pre-cracked (fracture mechanics) specimens for use in slow strain rate (SSR) tests to investigate the resistance of metallic materials to environmentally assisted cracking (EAC). While some investigators utilize SSR test techniques in combination with cyclic or fatigue loading, no attempt has been made to incorporate such techniques into this practice. 1.2 Slow strain rate testing is applicable to the evaluation of a wide variety of metallic materials in test environments which simulate aqueous, nonaqueous, and gaseous service environments over a wide range of temperatures and pressures that may cause EAC of susceptible materials. 1.3 The primary use of this practice is to furnish accepted procedures for the accelerated testing of the resistance of metallic materials to EAC under various environmental conditions. In many cases, the initiation of EAC is accelerated through the applic...

  6. Phenotyping mouse chromosome substitution strains reveal multiple QTLs for febrile seizure susceptibility.

    NARCIS (Netherlands)

    Hessel, E.V.; Gassen, K.L.I. van; Wolterink-Donselaar, I.G.; Stienen, P.J.; Fernandes, C.; Brakkee, J.H.; Kas, M.J.; Graan, P.N. de

    2009-01-01

    Febrile seizures (FS) are the most common seizure type in children and recurrent FS are a risk factor for developing temporal lobe epilepsy. Although the mechanisms underlying FS are largely unknown, recent family, twin and animal studies indicate that genetics are important in FS susceptibility.

  7. Microsatellite and mini-exon analysis of Mexican human DTU I Trypanosoma cruzi strains and their susceptibility to nifurtimox and benznidazole.

    Science.gov (United States)

    Martínez, Ignacio; Nogueda, Benjamín; Martínez-Hernández, Fernando; Espinoza, Bertha

    2013-03-01

    Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, and it affects as many as 10 million people in North and South America, where it represents a major public health problem. T. cruzi is a parasite with high genetic diversity, and it has been grouped into 6 discrete typing units (DTUs), designated as T. cruzi I (TcI) to T. cruzi VI (TcVI). Mexican isolates from humans and from vector insects have been primarily found to be TcI, and these isolates are likely to be the strains that cause the clinical manifestations observed in Mexico. However, genetic characterization and drug susceptibility assays are limited in Mexican TcI strains. In this work, 24 Mexican T. cruzi strains, obtained primarily from humans, were studied with 7 locus microsatellites and mini-exon gene by PCR. Also, drug susceptibility was evaluated by growth and mobility assays. All of the human strains belonged to TcI, and they could be further grouped through microsatellite analysis into 2 subgroups (microsatellite genotypes 1 and 2), which were not related to the host clinical status or biological origin of the strain. Two strains, both from wild mammals, belonged to the TcII-TcVI groups; these strains and the CL Brener strain constituted microsatellite genotype 3. The number of alleles in each locus was lower than reported for South American strains, and a departure from the Hardy-Weinberg equilibrium was observed. The susceptibility of these strains to nifurtimox and benznidazole was heterogeneous. T. cruzi strains characterized as microsatellite genotypes 2 and 3 were significantly more susceptible to benznidazole than strains of microsatellite genotype 1. Only 1 Mexican strain resistant to both drugs was found in this study.

  8. Antimicrobial susceptibility of bacteria isolated from neonatal foal samples submitted to a New Zealand veterinary pathology laboratory (2004 to 2013).

    Science.gov (United States)

    Toombs-Ruane, L J; Riley, C B; Kendall, A T; Hill, K E; Benschop, J; Rosanowski, S M

    2016-03-01

    To describe antimicrobial susceptibility, and identify antimicrobial resistance (AMR), in bacteria isolated from New Zealand foals. A database search was performed of submissions to a veterinary pathology laboratory between April 2004 and December 2013 for bacterial culture of samples from foals foals were examined, and 127 bacterial isolates were cultured from 64 (63%) foals. Of the 127 isolates, 32 (25%) were Streptococcus spp., 30 (24%) were Staphylococcus spp., 12 (10%) were Enterococcus spp. and 26 (21%) were Escherichia coli. Of 83 Gram-positive isolates, 57 (69%) were susceptible to penicillin. Over all isolates, 92/126 (73%) were susceptible to gentamicin and 117/126 (93%) to enrofloxacin; 62/82 (76%) of Gram-positive, and 22/42 (52%) of Gram-negative bacteria were susceptible to ceftiofur; 53/81 (65%) of Gram-positive, and 23/44 (52%) of Gram-negative bacteria were susceptible to tetracycline; 59/82 (72%) of Gram-positive, and 23/44 (43%) of Gram-negative bacteria were susceptible to trimethoprim-sulfonamide. Of 126 isolates, 33 (26%) had MDR; >1 isolate with MDR was cultured from 24/64 (38%) foals, and ≥2 isolates with MDR were recovered from 8/64 (13%) foals. Multi-drug resistance, including resistance to commonly used antimicrobials, was found in bacterial isolates from foals in New Zealand. The results of this study are of concern from a treatment perspective as they indicate a potential for antimicrobial treatment failure. For future surveillance of AMR and the creation of national guidelines, it is important to record more data on samples submitted for bacterial culture.

  9. Determination of Drug Susceptibility of Candida Strains Isolated From Patients With Recurrent Candida Vulvovaginitis and Investigation of Predisposing Factors of the Disease

    Directory of Open Access Journals (Sweden)

    Minooeianhaghighi MH

    2017-03-01

    Full Text Available Introduction: Recurrent Vulvovaginal Candidiasis RVVC(, which is mostly caused by Candida albicans C. albicans(, is the second common cause of genital tract infection in females. Th purpose of this research was to identify Candida isolates from RVVC, identify predisposing factors and determine antifungal effct of flconazole against Candida strains isolated from the patients. Methods: In this descriptive-laboratory study, 20 patients with confimed diagnosis of RVVC were selected. Yeast isolates were characterized using mycological standard methods, including culture on Sabouraud dextrose agar medium and CHROM agar, germ tube test and polymerase chain reaction-restriction fragment length polymorphism PCR-RFLP( technique. Th susceptibility of Candida isolates against flconazole was determined by microdilution broth method. Results: Th average age of the patients was 29.43 ± 4.63 years. Candida albicans was obtained from 100% of the samples. Th most common clinical sign was vaginal discharge 60%( in females with positive culture. Statistical correlations were observed between parturition frequency and low RVVC occurrence as well as between the previous antifungal therapy and RVVC occurrence. Th mean minimum inhibitory concentration MIC( and minimum fungicidal concentration MFC( of flconazole against diffrent C. albicans strains was determined as 45.3863 µg/mL and 63 µg/mL, respectively. Conclusion: Due to the uncertainty of diagnosis of this disease according to clinical symptoms and also, due to the resistance of Candida species, using culture and molecular methods are recommended as standard methods of diagnosis.

  10. Molecular Typing and Antimicrobial Susceptibility of Staphylococcus aureus Strains Isolated from Raw Milk, Cheese, Minced Meat, and Chicken Meat Samples

    Science.gov (United States)

    Karagöz, Alper

    2017-01-01

    The objectives of this study were: i) to detect the presence of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in raw milk, cheese, beef minced meat, and chicken meat samples; ii) to evaluate the antimicrobial susceptibility of the isolates; and iii) to determine clonal relation among the isolates by using pulsed-field gel electrophoresis (PFGE) method. Therefore, a total of 160 food samples were randomly collected between August 2014 and May 2015 in Hatay province, located in the southern Turkey. Twenty (12.5%) of the samples were found to be contaminated with S. aureus. A total of 40 isolates from the 20 positive samples were confirmed to be S. aureus by multiplex PCR based on 16S rRNA and nuc gene. The mec A gene was not detected in any of the S. aureus strains. In the present study, 39 out of 40 (97.5%) isolates were found to be resistant to one or more antibiotics. All of isolates were susceptible to gentamicin, oxacillin, and vancomycin. The highest resistance rate was detected in penicillin (95%) and ampicillin (92.5%), followed by tetracycline (30%), erythromycin (20%), ciprofloxacin (12.5%). Nine major patterns were determined by PFGE. In 6 of these patterns, thirty-six strains (90%) had identical PFGE profiles. PMID:28515641

  11. Isolation and determination antimicrobial susceptibility pattern of Enterobacter cloacae strains isolated from consumed powdered infant formula milk in NICU ward

    Directory of Open Access Journals (Sweden)

    Jalal Mardaneh

    2014-11-01

    Full Text Available Background: Enterobacter cloacae is a rod-shaped, gram-negative bacillus, from the family of Enterobacteriaceae. It is an opportunistic pathogen and causes disease in plants and humans (premature and immunocompromised persons of all age groups. The goal of this study was to isolate and determine antimicrobial susceptibility pattern of Enterobacter cloacae strains isolated from consumed powdered infant formula (PIF milk in Neonatal Intensive Care Unit (NICU ward. Material and Methods: In this cross-sectional study, a total of 125 consumed powdered infant formula milk in NICU ward were surveyed. Isolation and Identification of microorganisms was carried out according to FDA method. Antimicrobial susceptibility test was performed using the standard disc diffusion method based on CLSI (2011 recommendations. Results: Enterobacter cloacae was isolated from 2 (1.6% of 125 PIF milk samples. The results showed that isolated strains are sensitive to most antibiotics. All isolates were resistant to amoxicillin. Conclusion: Since the infant formula (PIF samples are unsterile products and contamination could occure during different steps, it is imperative to prepare the infant formula milk foods according to the manufacturer’s instruction and in an aseptic condition. Contamination of PIF only could be reduced or prevented by monitoring the critical control points and taking appropriate action during the processing.

  12. Comparisons of Transcriptional Profiles of Gut Genes between Cry1Ab-Resistant and Susceptible Strains of Ostrinia nubilalis Revealed Genes Possibly Related to the Adaptation of Resistant Larvae to Transgenic Cry1Ab Corn

    Directory of Open Access Journals (Sweden)

    Jianxiu Yao

    2017-01-01

    Full Text Available A microarray developed on the basis of 2895 unique transcripts from larval gut was used to compare gut gene expression profiles between a laboratory-selected Cry1Ab-resistant (R strain and its isoline susceptible (S strain of the European corn borer (Ostrinia nubilalis after the larvae were fed the leaves of transgenic corn (MON810 expressing Cry1Ab or its non-transgenic isoline for 6 h. We revealed 398 gut genes differentially expressed (i.e., either up- or down-regulated genes with expression ratio ≥2.0 in S-strain, but only 264 gut genes differentially expressed in R-strain after being fed transgenic corn leaves. Although the percentages of down-regulated genes among the total number of differentially expressed genes (50% in S-strain and 45% in R-strain were similar between the R- and S-strains, the expression ratios of down-regulated genes were much higher in S-strain than in R-strain. We revealed that 17 and 9 significantly up- or down-regulated gut genes from S and R-strain, respectively, including serine proteases and aminopeptidases. These genes may be associated with Cry1Ab toxicity by degradation, binding, and cellular defense. Overall, our study suggests enhanced adaptation of Cry1Ab-resistant larvae on transgenic Cry1Ab corn as revealed by lower number and lower ratios of differentially expressed genes in R-strain than in S-strain of O. nubilalis.

  13. Comparisons of Transcriptional Profiles of Gut Genes between Cry1Ab-Resistant and Susceptible Strains of Ostrinia nubilalis Revealed Genes Possibly Related to the Adaptation of Resistant Larvae to Transgenic Cry1Ab Corn.

    Science.gov (United States)

    Yao, Jianxiu; Zhu, Yu-Cheng; Lu, Nanyan; Buschman, Lawrent L; Zhu, Kun Yan

    2017-01-30

    A microarray developed on the basis of 2895 unique transcripts from larval gut was used to compare gut gene expression profiles between a laboratory-selected Cry1Ab-resistant (R) strain and its isoline susceptible (S) strain of the European corn borer (Ostrinia nubilalis) after the larvae were fed the leaves of transgenic corn (MON810) expressing Cry1Ab or its non-transgenic isoline for 6 h. We revealed 398 gut genes differentially expressed (i.e., either up- or down-regulated genes with expression ratio ≥2.0) in S-strain, but only 264 gut genes differentially expressed in R-strain after being fed transgenic corn leaves. Although the percentages of down-regulated genes among the total number of differentially expressed genes (50% in S-strain and 45% in R-strain) were similar between the R- and S-strains, the expression ratios of down-regulated genes were much higher in S-strain than in R-strain. We revealed that 17 and 9 significantly up- or down-regulated gut genes from S and R-strain, respectively, including serine proteases and aminopeptidases. These genes may be associated with Cry1Ab toxicity by degradation, binding, and cellular defense. Overall, our study suggests enhanced adaptation of Cry1Ab-resistant larvae on transgenic Cry1Ab corn as revealed by lower number and lower ratios of differentially expressed genes in R-strain than in S-strain of O. nubilalis.

  14. In vitro antimicrobial susceptibility of Brachyspira hyodysenteriae strains isolated in Japan from 1985 to 2009.

    Science.gov (United States)

    Ohya, Tatsuo; Sueyoshi, Masuo

    2010-12-01

    The antimicrobial susceptibilities of 72 Brachyspira hyodysenteriae isolates collected from clinical cases of swine dysentery (SD) in 11 prefectures in Japan between 1985 and 2009 were investigated by an agar dilution method using five antimicrobial agents. There is a tendency of Japanese field isolates of B. hyodysenteriae to acquire resistance to the main antimicrobials used in SD treatment such as tiamulin, valnemulin, and efrotomycin. A responsible approach for selection and use of antimicrobial agents is required for SD treatment.

  15. The precision and robustness of published protocols for disc diffusion assays of antimicrobial agent susceptibility: an inter-laboratory study

    DEFF Research Database (Denmark)

    Gabhainn, S.N.; Bergh, Ø.; Dixon, B.

    2004-01-01

    The precision of the disc diffusion protocols previously published by Alderman and Smith (Aquaculture 196 (2002) 211) was analysed in a seven-laboratory trial using Escherichia coli ATCC 25922 as the test strain. Discs containing seven antimicrobial agents were employed and 2899 zone size...... to investigate the influence of incubation time of zone size. The intra-laboratory precision was relatively high with the mean of the coefficients of variation calculated for each laboratory and each agent being 4.7%. In contrast, the inter-laboratory precision was very much lower with the mean of the values...... for each agent being 11.1%. Significant influences on zone size were detected for all three parameters of the protocol. Media source effects were particularly notable with respect to oxytetracycline and oxolinic acid discs, disc source effects with respect to ampicillin and sulphamethoxazole...

  16. Ambiguous Role of Interleukin-12 in Yersinia enterocolitica Infection in Susceptible and Resistant Mouse Strains

    Science.gov (United States)

    Bohn, Erwin; Schmitt, Edgar; Bielfeldt, Claudia; Noll, Annette; Schulte, Ralf; Autenrieth, Ingo B.

    1998-01-01

    Endogenous interleukin-12 (IL-12) mediates protection against Yersinia enterocolitica in C57BL/6 mice by triggering gamma interferon (IFN-γ) production in NK and CD4+ T cells. Administration of exogenous IL-12 confers protection against yersiniae in Yersinia-susceptible BALB/c mice but exacerbates yersiniosis in resistant C57BL/6 mice. Therefore, we wanted to dissect the different mechanisms exerted by IL-12 during Yersinia infections by using different models of Yersinia-resistant and -susceptible mice, including resistant C57BL/6 mice, susceptible BALB/c mice, intermediate-susceptible wild-type 129/Sv mice, 129/Sv IFN-γ-receptor-deficient (IFN-γR−/−) mice and C57BL/6 tumor necrosis factor (TNF) receptor p55 chain-deficient (TNFR p55−/−) mice. IFN-γR−/− mice turned out to be highly susceptible to infection by Y. enterocolitica compared with IFN-γR+/+ mice. Administration of IL-12 was protective in IFN-γR+/+ mice but not in IFN-γR−/− mice, suggesting that IFN-γR-induced mechanisms are essential for IL-12-induced resistance against yersiniae. BALB/c mice could be rendered Yersinia resistant by administration of anti-CD4 antibodies or by administration of IL-12. In contrast, C57BL/6 mice could be rendered more resistant by administration of transforming growth factor β (TGF-β). Furthermore, IL-12-triggered toxic effects in C57BL/6 mice were abrogated by coadministration of TGF-β. While administration of IL-12 alone increased TNF-α levels, administration of TGF-β or TGF-β plus IL-12 decreased both TNF-α and IFN-γ levels in Yersinia-infected C57BL/6 mice. Moreover, IL-12 did not induce toxicity in Yersinia-infected TNFR p55−/− mice, suggesting that TNF-α accounts for IL-12-induced toxicity. Taken together, IL-12 may induce different effector mechanisms in BALB/c and C57BL/6 mice resulting either in protection or exacerbation. These results are important for understanding the critical balance of proinflammatory and regulatory

  17. Suscetibilidade da linhagem de células Vero a cepas vacinais do vírus do sarampo Susceptibility of Vero cell line to vaccine strains of the measles virus

    Directory of Open Access Journals (Sweden)

    Célia Sayoko Takata

    1994-06-01

    Full Text Available A suscetibilidade da linhagem de células Vero ao vírus do sarampo é bem conhecida e sua utilização no controle da potência da vacina contra o sarampo é amplamente difundida. Com o objetivo de comparar a suscetibilidade de células Vero empregadas em titulações, amostras provenientes de dois laboratórios controladores (Vero IB e Vero INCQS, foram testadas frente a três cepas vacinais: Moraten, Schwarz e Biken CAM-70. Foram titulados 72 lotes de vacinas contra o sarampo, sendo 25 produzidos com a cepa Moraten, 24 com a cepa Schwarz e 23 com a cepa Biken CAM-70. A análise estatística dos resultados obtidos nas titulações, feita através dos testes Limites para uma Média e "t" de Student, mostrou que para as cepas Moraten e Biken CAM-70, as diferenças de títulos não foram estatisticamente significantes, o mesmo não ocorrendo com a cepa Schwarz, para a qual as células Vero IB se mostraram mais sensíveis.Vero cells used by distinct measles vaccine control laboratories had their susceptibility to Moraten, Schwarz and Biken CAM-70 vaccine strains assayed. Of a total of 72 lots of measles vaccine whose potency was titrated by microtechnique in two Vero cell samples (Vero IB and Vero INCQS, 25 had been produced with Moraten strain, 24 with Schwarz and 23 with Biken CAM-70. The statistical analysis of the results demonstrated that both Vero cells assayed presented comparable susceptibility to Moraten and Biken CAM-70 strains. As to the Schwarz strain, Vero IB cells were more susceptible than the other cell sample tested, thus confirming the existence of different sensitivities of Vero cells to some measles vaccine strains, or even to viruses derived from the same strain but with different passage histories. An altered cell susceptibility to virus replication may significantly alter the results in potency testing. Such alteration may be caused not only by the adoption of distinct protocols for the maintenance of cell cultures by

  18. A Comparative Study of the Organic Acid Content of the Hemolymph of Schistosoma mansoni-Resistant and Susceptible Strains of Biomphalaria glabrata

    Directory of Open Access Journals (Sweden)

    José Clecildo Barreto Bezerra

    1997-05-01

    Full Text Available The freshwater snail Biomphalaria glabrata is an intermediate host of the trematode Schistosoma mansoni. However, some strains of B. glabrata are resistant to successful infection by S. mansoni larvae. The present work examines the profile of organic acids present in S. mansoni-resistant and -susceptible strains of B. glabrata, in order to determine whether the type of organic acid present is related to susceptibility. The organic acids were extracted from the hemolymph of two susceptible B. glabrata strains (PR, Puerto Rico and Ba, Jacobina-Bahia from Brazil, and from the resistant strains 13-16-R1 and 10R2, using solid phase extraction procedures followed by high performance liquid chromatography. The organic acids obtained were analyzed and identified by comparison with known standards. Pyruvate, lactate, succinate, malate, fumarate, acetate, propionate, ß-hydroxybutyrate and acetoacetate were detected in all hemolymph samples. Under standard conditions, the concentration of each of these substances varied among the strains tested and appeared to be specific for each strain. An interesting variation was the low concentration of pyruvate in the hemolymph of PR-snails. Only the concentration of fumarate was consistently different (p£ 0.05 between resistant and susceptible strains

  19. Water Sources in a Zoological Park Harbor Genetically Diverse Strains of Clostridium Perfringens Type A with Decreased Susceptibility to Metronidazole.

    Science.gov (United States)

    Álvarez-Pérez, Sergio; Blanco, José L; Peláez, Teresa; Martínez-Nevado, Eva; García, Marta E

    2016-11-01

    The presence of Clostridium perfringens in water is generally regarded as an indicator of fecal contamination, and exposure to waterborne spores is considered a possible source of infection for animals. We assessed the presence and genetic diversity of C. perfringens in water sources in a zoological park located in Madrid (Spain). A total of 48 water samples from 24 different sources were analyzed, and recovered isolates were toxinotyped, genotyped by fluorophore-enhanced repetitive polymerase chain reaction (rep-PCR) fingerprinting and tested for antimicrobial susceptibility. C. perfringens was recovered from 43.8 % of water samples and 50 % of water sources analyzed. All isolates (n = 70) were type A and 42.9 % were β2-toxigenic (i.e., cpb2+), but none contained the enterotoxin-encoding gene (cpe). Isolates belonged to 15 rep-PCR genotypes and most genetic diversity (88 %) was distributed among isolates obtained from the same sample. Most isolates displayed intermediate susceptibility (57.1 %; MIC = 16 μg ml(-1)) or resistance (5.7 %; MIC ≥ 32 μg ml(-1)) to metronidazole. No resistance to other antimicrobials was detected, although some isolates showed elevated MICs to erythromycin and/or linezolid. Finally, a marginally significant association between absence of cpb2 and decreased susceptibility to metronidazole (MIC ≥ 16 μg ml(-1)) was detected. In conclusion, our results reveal a high prevalence of C. perfringens type A in the studied water reservoirs, which constitutes a health risk for zoo animals. The elevated MICs to metronidazole observed for genetically diverse isolates is a cause of additional concern, but more work is required to clarify the significance of reduced metronidazole susceptibility in environmental strains.

  20. In vivo evolution of tigecycline-non-susceptible Klebsiella pneumoniae strains in patients: relationship between virulence and resistance.

    Science.gov (United States)

    Lin, Yi-Tsung; Huang, Yi-Wei; Huang, Hsin-Hui; Yang, Tsuey-Ching; Wang, Fu-Der; Fung, Chang-Phone

    2016-11-01

    Tigecycline resistance among Klebsiella pneumoniae isolates has been increasingly reported. We aimed to investigate the relationship among in vivo acquisition of tigecycline resistance in K. pneumoniae clinical isolates, the underlying molecular mechanisms and bacterial virulence. Clinical isolates of K. pneumoniae from the same patient in a medical centre in Taiwan that were initially tigecycline-susceptible (TS) and then became tigecycline-non-susceptible (TNS) were identified. Clinical data were collected. All isolates were subjected to MIC determination by Etest, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), virulence factor determination, and growth rate and mouse lethality studies. Quantitative RT-PCR was performed to analyse acrA, oqxA, ramA and rarA expressions. The presence of mutations in acrR, ramR, oqxR and rpsJ were analysed by DNA sequencing. Five isogenic paired isolates were determined by PFGE fingerprinting. TNS K. pneumoniae appeared after treatment with a variety of antibiotics among patients infected with TS K. pneumoniae. TNS K. pneumoniae isolates were associated with upregulation of RamA and/or RarA and the corresponding AcrAB and/or OqxAB efflux pump(s), respectively. Various mutations in negative regulatory genes (ramR and oqxR) accounted for overexpression of ramA and rarA, respectively. Three of the five paired isolates showed similar growth rates and virulence between TS and TNS isolates. Two TNS K. pneumoniae strains belonging to capsular types K1 and K20 retained their high virulence. In conclusion, some TNS K. pneumoniae strains derived from TS isolates did not compromise their virulence. Dissemination of these highly pathogenic and resistant strains would be of major concern in the future. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  1. Monitoring changes in bemisia tabaci susceptibility to neonicotinoid insecticides in Arizona and California

    Science.gov (United States)

    Laboratory bioassays were carried out on field-collected and laboratory strains of Bemisia tabaci to evaluate relative toxicities of four neonicotinoid insecticides: acetamiprid, dinotefuran, imidacloprid and thiamethoxam. Susceptibility to all four neonicotinoids in leaf-uptake bioassays varied co...

  2. Relation between genetic markers of drug resistance and susceptibility profile of clinical Neisseria gonorrhoeae strains.

    Science.gov (United States)

    Ilina, Elena N; Vereshchagin, Vladimir A; Borovskaya, Alexandra D; Malakhova, Maja V; Sidorenko, Sergei V; Al-Khafaji, Nazar C; Kubanova, Anna A; Govorun, Vadim M

    2008-06-01

    The main goal of this work is to clarify the predictive value of known genetic markers of Neisseria gonorrhoeae resistance to penicillin, tetracycline, and fluoroquinolones. The correlation between the presence of certain genetic markers and susceptibility of N. gonorrhoeae isolates to penicillin, tetracycline, and fluoroquinolones has been analyzed by means of statistical methods. Susceptibility testing with penicillin, tetracycline, and fluoroquinolones was performed by the agar dilution method. N. gonorrhoeae genomic DNA was isolated. The presence of bla(TEM-1) and tet(M) genes was analyzed by PCR. A novel method of polymorphism discovery based on a minisequencing reaction followed by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry was applied for the analysis of chromosomal N. gonorrhoeae genes involved in antimicrobial resistance development. Clinical N. gonorrhoeae isolates (n = 464) were collected. Susceptibility levels to penicillin, tetracycline, and fluoroquinolones were found to be 25.9%, 35.9%, and 54.1%, respectively. Among the 19 N. gonorrhoeae isolates with penicillin MICs of > or =4 microg/ml, the bla(TEM-1) gene was detected in 12. The Tet(M) determinant was found in 4 of 12 N. gonorrhoeae isolates with tetracycline MICs of > or =16 microg/ml. The chromosomal genetic markers of penicillin and tetracycline resistance were detected especially in isolates with penicillin MICs of 0.25 to 2.0 microg/ml and tetracycline MICs of 0.5 to 4 microg/ml. Mutations in GyrA and ParC were found in 208 of 211 quinolone-resistant N. gonorrhoeae isolates. This work is the first representative molecular research of the N. gonorrhoeae population in Russia. Information about the prevalence of antibiotic resistance mechanisms and the positive predictive value of certain genetic determinants is given. The positive predictive values of the analyzed genetic markers were found to be different for fluoroquinolones (90.3%), penicillin (91.1%), and

  3. The novel 2016 WHO Neisseria gonorrhoeae reference strains for global quality assurance of laboratory investigations: phenotypic, genetic and reference genome characterization.

    Science.gov (United States)

    Unemo, Magnus; Golparian, Daniel; Sánchez-Busó, Leonor; Grad, Yonatan; Jacobsson, Susanne; Ohnishi, Makoto; Lahra, Monica M; Limnios, Athena; Sikora, Aleksandra E; Wi, Teodora; Harris, Simon R

    2016-11-01

    Gonorrhoea and MDR Neisseria gonorrhoeae remain public health concerns globally. Enhanced, quality-assured, gonococcal antimicrobial resistance (AMR) surveillance is essential worldwide. The WHO global Gonococcal Antimicrobial Surveillance Programme (GASP) was relaunched in 2009. We describe the phenotypic, genetic and reference genome characteristics of the 2016 WHO gonococcal reference strains intended for quality assurance in the WHO global GASP, other GASPs, diagnostics and research worldwide. The 2016 WHO reference strains (n = 14) constitute the eight 2008 WHO reference strains and six novel strains. The novel strains represent low-level to high-level cephalosporin resistance, high-level azithromycin resistance and a porA mutant. All strains were comprehensively characterized for antibiogram (n = 23), serovar, prolyliminopeptidase, plasmid types, molecular AMR determinants, N. gonorrhoeae multiantigen sequence typing STs and MLST STs. Complete reference genomes were produced using single-molecule PacBio sequencing. The reference strains represented all available phenotypes, susceptible and resistant, to antimicrobials previously and currently used or considered for future use in gonorrhoea treatment. All corresponding resistance genotypes and molecular epidemiological types were described. Fully characterized, annotated and finished references genomes (n = 14) were presented. The 2016 WHO gonococcal reference strains are intended for internal and external quality assurance and quality control in laboratory investigations, particularly in the WHO global GASP and other GASPs, but also in phenotypic (e.g. culture, species determination) and molecular diagnostics, molecular AMR detection, molecular epidemiology and as fully characterized, annotated and finished reference genomes in WGS analysis, transcriptomics, proteomics and other molecular technologies and data analysis. © The Author 2016. Published by Oxford University Press on behalf of the

  4. Origins of albino and hooded rats: implications from molecular genetic analysis across modern laboratory rat strains.

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    Takashi Kuramoto

    Full Text Available Albino and hooded (or piebald rats are one of the most frequently used laboratory animals for the past 150 years. Despite this fact, the origin of the albino mutation as well as the genetic basis of the hooded phenotype remained unclear. Recently, the albino mutation has been identified as the Arg299His missense mutation in the Tyrosinase gene and the hooded (H locus has been mapped to the ∼460-kb region in which only the Kit gene exists. Here, we surveyed 172 laboratory rat strains for the albino mutation and the hooded (h mutation that we identified by positional cloning approach to investigate possible genetic roots and relationships of albino and hooded rats. All of 117 existing laboratory albino rats shared the same albino missense mutation, indicating they had only one single ancestor. Genetic fine mapping followed by de novo sequencing of BAC inserts covering the H locus revealed that an endogenous retrovirus (ERV element was inserted into the first intron of the Kit gene where the hooded allele maps. A solitary long terminal repeat (LTR was found at the same position to the ERV insertion in another allele of the H locus, which causes the so called Irish (h(i phenotype. The ERV and the solitary LTR insertions were completely associated with the hooded and Irish coat patterns, respectively, across all colored rat strains examined. Interestingly, all 117 albino rat strains shared the ERV insertion without any exception, which strongly suggests that the albino mutation had originally occurred in hooded rats.

  5. A comparison of stress tolerance in YPD and industrial lignocellulose-based medium among industrial and laboratory yeast strains.

    Science.gov (United States)

    Albers, Eva; Larsson, Christer

    2009-08-01

    In general, it is believed that fermentation by yeast under harsh industrial conditions, especially if substrates such as wood hydrolysate or lignocellulosic substrates are used, requires the use of so-called industrial strains. In order to check whether this is always true, a comparison of performance was made using two industrial strains and four commonly used laboratory strains, the haploid and diploid versions of CEN-PK and X2180, under industrially relevant stress conditions. The industrial strains were a Swedish commercial baker's yeast strain and a strain previously isolated from an industrial bioethanol production plant using lignocellulosic substrate. Stress conditions included, apart from growth in the lignocellulosic substrate itself, elevated concentrations of glucose, NaCl, ethanol, and lactate as well as low pH. Results showed that, indeed, the strain adapted to lignocellulosic substrate also possessed the highest growth rate as well as shortest duration of the lag phase in this type of medium. However, the higher the additional stress level, the lower the difference compared to other strains, and X2180 in particular displayed a high resistance to these additional stress conditions. Furthermore, no difference in performance could be detected between the haploid or diploid versions of the laboratory strains. It might be that, at least under some circumstances, a laboratory strain such as X2180 could be an industrially attractive production organism with the advantage of facilitating the possibilities for making controlled genetic manipulations.

  6. Phenotypic, molecular characterization, antimicrobial susceptibility and draft genome sequence of Corynebacterium argentoratense strains isolated from clinical samples

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    I. Fernández-Natal

    2016-03-01

    Full Text Available During a 12-year period we isolated five Corynebacterium argentoratense strains identified by phenotypic methods, including the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF and 16S rRNA gene sequencing. In addition, antimicrobial susceptibility was determined, and genome sequencing for the detection of antibiotic resistance genes was performed. The organisms were isolated from blood and throat cultures and could be identified by all methods used. All strains were resistant to cotrimoxazole, and resistance to β-lactams was partly present. Two strains were resistant to erythromycin and clindamycin. The draft genome sequences of theses isolates revealed the presence of the erm(X resistance gene that is embedded in the genetic structure of the transposable element Tn5423. Although rarely reported as a human pathogen, C. argentoratense can be involved in bacteraemia and probably in other infections. Our results also show that horizontal transfer of genes responsible for antibiotic resistance is occurring in this species.

  7. Caloric restriction in lean and obese strains of laboratory rat: effects on body composition, metabolism, growth and overall health

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    U.S. Environmental Protection Agency — Data related to obese and lean strains of rat commonly used in the laboratory that are calorically restricted and its effects on physiologic parameters (Body...

  8. Effect of genetic strain and gender on age-related changes in body composition of the laboratory rat.

    Data.gov (United States)

    U.S. Environmental Protection Agency — Body composition data for common laboratory strains of rat as a function of age. This dataset is associated with the following publication: Gordon , C., K. Jarema ,...

  9. Field and laboratory studies of the susceptibility of the green treefrog (Hyla cinerea to Batrachochytrium dendrobatidis infection.

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    Laura A Brannelly

    Full Text Available Amphibians worldwide are experiencing devastating declines, some of which are due to the amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd. Populations in the southeastern United States, however, have not been noticeably affected by the pathogen. The green treefrog (Hyla cinerea is abundant and widespread in the southeastern United States, but has not been documented to harbor Bd infection. This study examined the susceptibility of H. cinerea to two strains of Bd in the lab and the prevalence of infection in wild populations of this species in southeastern Louisiana. Although we were able to infect H. cinerea with Bd in the lab, we did not observe any clinical signs of chytridiomycosis. Furthermore, infection by Bd does not appear to negatively affect body condition or growth rate of post-metamorphic individuals. We found no evidence of infection in surveys of wild H. cinerea. Our results suggest that H. cinerea is not susceptible to chytridiomycosis post-metamorphosis and probably is not an important carrier of the fungal pathogen Bd in the southeastern United States, although susceptibility at the larval stage remains unknown.

  10. Effect of gamma radiation on the toxicity of milbemectin and chlorfenapyr in acaricide resistant and susceptible strains of Tetranychus urticae Koch (Acari: Tetranychidae)

    Energy Technology Data Exchange (ETDEWEB)

    Nicastro, Roberto L.; Arthur, Valter; Machi, Andre R., E-mail: rnicastro@cena.usp.br, E-mail: arthur@cena.usp.br [Laboratorio de Radiobiologia e Ambiente (CENA/USP), Piracicaba, SP (Brazil); Sato, Mario E., E-mail: mesato@biologico.sp.gov.br [Laboratorio de Acarologia, Instituto Biologico, Campinas, SP (Brazil)

    2011-07-01

    The spider mite Tetranychus urticae Koch is considered one of the most important phytophagous mites, causing considerable damage in several agricultural crops. The aim of this study was to evaluate the effect of gamma radiation on the toxicity of the acaricides milbemectin and chlorfenapyr in resistant and susceptible strains of T. urticae. The R and S strains for milbemectin and chlorfenapyr were irradiated with gamma radiation at Gamma cell-220 source at doses of 5, 10, 20, 40 e 80 Gy. Five concentrations of milbemectin and chlorfenapyr were evaluated, making applications 24 hours after irradiation. Mites of the controls were sprayed with the same acaricide concentrations used for the R and S strains but they were not exposed to gamma radiation. Experiments on the effects of gamma radiation on the growth rates of mites for acaricide resistant and susceptible strains of T. urticae were also carried out. Tests with the Milbemectin S strain showed an increased susceptibility to the acaricide milbemectin, when the mites were irradiated (20 Gy), in comparison with the control (non irradiated mites). For the Milbemectin R strain, there was no significant influence of gamma irradiation on the toxicity of milbemectin to the mites of this strain. For the Chlorfenapyr S strain, the effect of gamma radiation was similar to that observed for Milbemectin S strain, with increased toxicity of chlorfenapyr to the mites of this susceptible strain. In the case of the Chlorfenapyr R strain, the mites exposed to gamma radiation showed to be more tolerant to chlorfenapyr, considering the LC{sub 10} values. The same trend was observed for the LC{sub 50} values, however, there was no significant difference with the control. The experiments showed that doses of 200 and 300 Gy eliminated the mite populations of acaricide resistant and susceptible strains of T. urticae, in a period of ten days. The dose of 100 Gy did not lead to total elimination of the mite populations, but reduced

  11. Comparison of Resistant and Susceptible Strains of Trichomons vaginalis to Metronidazole Using PCR Method

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    M Fallah

    2012-09-01

    Full Text Available Background: Metronidazole is drug of choice recommended by WHO for treatment of trichomoniasis, however, some reports claims drug resistance in Trichomonas vaginalis isolates recently. The objective of this study was to determine the minimum lethal concentration (MLC of metronidazole in resistant and sensitive strains, as well as genetic patterns of these stains by PCR method. Methods: From February 2006 to March 2007, in a cross sectional study, clinical and wet mount examination of vaginal smear along with culture were performed on 683 women attending to public and private outpatient clinics in Hamadan. Trichomoniasis marked based on major clinical symptoms. Diagnosis confirmed using wet mount microscopically and culture in Diamond medium. A serial concentration of metronidazole was provided and all isolated Trichomonas strains (resistant and sensitive tested by standard method. Finally, all sensitive and resistant strains examined by PCR technique. Results: Only 15/683, (2.2% of patients clinically diagnosed trichomonal vaginitis were positive for T. vaginalis by wet smear and culture. The minimum lethal concentration (MLC for clinically sensitive isolates was 25 µg/ml; however, this concentration for resistant isolates was 200 µg/ml after 24 h and 100 µg/ml after 50 h. The results of PCR examination of DNA from sensitive and resistant isolates had same pattern. The lanes appeared by two primers were 98 bp and 261 bp for both clinically sensitive and resistant strains. Conclusion: Resistance to metronidazole in T. vaginalis has not relation to genetic variations and might be related to some physiologic pathways of organism.

  12. Effect of genetic strain and gender on age-related changes in body composition of the laboratory rat.

    Science.gov (United States)

    Body composition data for common laboratory strains of rat as a function of age.This dataset is associated with the following publication:Gordon , C., K. Jarema , A. Johnstone , and P. Phillips. Effect of Genetic Strain and Gender on Age-Related Changes in Body Composition of the Laboratory Rat. Physiology & Behavior. Elsevier B.V., Amsterdam, NETHERLANDS, 153(1): 56-63, (2016).

  13. Accurate assessment of antibiotic susceptibility and screening resistant strains of a bacterial population by linear gradient plate.

    Science.gov (United States)

    Liu, Yuqing; Li, Jingran; Du, Jiafa; Hu, Ming; Bai, Hua; Qi, Jing; Gao, Chao; Wei, Tiantian; Su, Hong; Jin, Jianling; Gao, Peiji

    2011-10-01

    The dynamics of a bacterial population exposed to the minimum inhibitory concentration (MIC) of an antibiotic is an important issue in pharmacological research. Therefore, a novel antibiotic susceptibility test is urgently needed that can both precisely determine the MIC and accurately select antibiotic-resistant strains from clinical bacterial populations. For this purpose, we developed a method based on Fick's laws of diffusion using agar plates containing a linear gradient of antibiotic. The gradient plate contained two layers. The bottom layer consisted of 15 mL agar containing the appropriate concentration of enrofloxacin and allowed to harden in the form of a wedge with the plate slanted such that the entire bottom was just covered. The upper layer consisted of 15 mL plain nutrient agar added with the plate held in the horizontal position. After allowing vertical diffusion of the drug from the bottom agar layer for 12 h, the enrofloxacin concentration was diluted in proportion to the ratio of the agar layer thicknesses. The uniform linear concentration gradient was verified by measuring the enrofloxacin concentration on the agar surface. When heavy bacterial suspensions were spread on the agar surface and incubated for more than 12 h, only resistant cells were able to form colonies beyond the boundary of confluent growth of susceptible cells. In this way, the true MIC of enrofloxacin was determined. The MICs obtained using this linear gradient plate were consistent with those obtained using conventional antibiotic susceptibility tests. Discrete colonies were then spread onto a gradient plate with higher antibiotic concentrations; the boundary line increased significantly, and gene mutations conferring resistance were identified. This new method enables the rapid identification of resistant strains in the bacterial population. Use of the linear gradient plate can easily identify the precise MIC and reveal the dynamic differentiation of bacteria near the MIC

  14. GC-MS-Based Metabonomic Profiling Displayed Differing Effects of Borna Disease Virus Natural Strain Hu-H1 and Laboratory Strain V Infection in Rat Cortical Neurons.

    Science.gov (United States)

    Liu, Siwen; Bode, Liv; Zhang, Lujun; He, Peng; Huang, Rongzhong; Sun, Lin; Chen, Shigang; Zhang, Hong; Guo, Yujie; Zhou, Jingjing; Fu, Yuying; Zhu, Dan; Xie, Peng

    2015-08-17

    Borna disease virus (BDV) persists in the central nervous systems of a wide variety of vertebrates and causes behavioral disorders. Previous studies have revealed that metabolic perturbations are associated with BDV infection. However, the pathophysiological effects of different viral strains remain largely unknown. Rat cortical neurons infected with human strain BDV Hu-H1, laboratory BDV Strain V, and non-infected control (CON) cells were cultured in vitro. At day 12 post-infection, a gas chromatography coupled with mass spectrometry (GC-MS) metabonomic approach was used to differentiate the metabonomic profiles of 35 independent intracellular samples from Hu-H1-infected cells (n = 12), Strain V-infected cells (n = 12), and CON cells (n = 11). Partial least squares discriminant analysis (PLS-DA) was performed to demonstrate discrimination between the three groups. Further statistical testing determined which individual metabolites displayed significant differences between groups. PLS-DA demonstrated that the whole metabolic pattern enabled statistical discrimination between groups. We identified 31 differential metabolites in the Hu-H1 and CON groups (21 decreased and 10 increased in Hu-H1 relative to CON), 35 differential metabolites in the Strain V and CON groups (30 decreased and 5 increased in Strain V relative to CON), and 21 differential metabolites in the Hu-H1 and Strain V groups (8 decreased and 13 increased in Hu-H1 relative to Strain V). Comparative metabonomic profiling revealed divergent perturbations in key energy and amino acid metabolites between natural strain Hu-H1 and laboratory Strain V of BDV. The two BDV strains differentially alter metabolic pathways of rat cortical neurons in vitro. Their systematic classification provides a valuable template for improved BDV strain definition in future studies.

  15. GC–MS-Based Metabonomic Profiling Displayed Differing Effects of Borna Disease Virus Natural Strain Hu-H1 and Laboratory Strain V Infection in Rat Cortical Neurons

    Science.gov (United States)

    Liu, Siwen; Bode, Liv; Zhang, Lujun; He, Peng; Huang, Rongzhong; Sun, Lin; Chen, Shigang; Zhang, Hong; Guo, Yujie; Zhou, Jingjing; Fu, Yuying; Zhu, Dan; Xie, Peng

    2015-01-01

    Borna disease virus (BDV) persists in the central nervous systems of a wide variety of vertebrates and causes behavioral disorders. Previous studies have revealed that metabolic perturbations are associated with BDV infection. However, the pathophysiological effects of different viral strains remain largely unknown. Rat cortical neurons infected with human strain BDV Hu-H1, laboratory BDV Strain V, and non-infected control (CON) cells were cultured in vitro. At day 12 post-infection, a gas chromatography coupled with mass spectrometry (GC–MS) metabonomic approach was used to differentiate the metabonomic profiles of 35 independent intracellular samples from Hu-H1-infected cells (n = 12), Strain V-infected cells (n = 12), and CON cells (n = 11). Partial least squares discriminant analysis (PLS-DA) was performed to demonstrate discrimination between the three groups. Further statistical testing determined which individual metabolites displayed significant differences between groups. PLS-DA demonstrated that the whole metabolic pattern enabled statistical discrimination between groups. We identified 31 differential metabolites in the Hu-H1 and CON groups (21 decreased and 10 increased in Hu-H1 relative to CON), 35 differential metabolites in the Strain V and CON groups (30 decreased and 5 increased in Strain V relative to CON), and 21 differential metabolites in the Hu-H1 and Strain V groups (8 decreased and 13 increased in Hu-H1 relative to Strain V). Comparative metabonomic profiling revealed divergent perturbations in key energy and amino acid metabolites between natural strain Hu-H1 and laboratory Strain V of BDV. The two BDV strains differentially alter metabolic pathways of rat cortical neurons in vitro. Their systematic classification provides a valuable template for improved BDV strain definition in future studies. PMID:26287181

  16. GC–MS-Based Metabonomic Profiling Displayed Differing Effects of Borna Disease Virus Natural Strain Hu-H1 and Laboratory Strain V Infection in Rat Cortical Neurons

    Directory of Open Access Journals (Sweden)

    Siwen Liu

    2015-08-01

    Full Text Available Borna disease virus (BDV persists in the central nervous systems of a wide variety of vertebrates and causes behavioral disorders. Previous studies have revealed that metabolic perturbations are associated with BDV infection. However, the pathophysiological effects of different viral strains remain largely unknown. Rat cortical neurons infected with human strain BDV Hu-H1, laboratory BDV Strain V, and non-infected control (CON cells were cultured in vitro. At day 12 post-infection, a gas chromatography coupled with mass spectrometry (GC–MS metabonomic approach was used to differentiate the metabonomic profiles of 35 independent intracellular samples from Hu-H1-infected cells (n = 12, Strain V-infected cells (n = 12, and CON cells (n = 11. Partial least squares discriminant analysis (PLS-DA was performed to demonstrate discrimination between the three groups. Further statistical testing determined which individual metabolites displayed significant differences between groups. PLS-DA demonstrated that the whole metabolic pattern enabled statistical discrimination between groups. We identified 31 differential metabolites in the Hu-H1 and CON groups (21 decreased and 10 increased in Hu-H1 relative to CON, 35 differential metabolites in the Strain V and CON groups (30 decreased and 5 increased in Strain V relative to CON, and 21 differential metabolites in the Hu-H1 and Strain V groups (8 decreased and 13 increased in Hu-H1 relative to Strain V. Comparative metabonomic profiling revealed divergent perturbations in key energy and amino acid metabolites between natural strain Hu-H1 and laboratory Strain V of BDV. The two BDV strains differentially alter metabolic pathways of rat cortical neurons in vitro. Their systematic classification provides a valuable template for improved BDV strain definition in future studies.

  17. Genetic Characterization of Spondweni and Zika Viruses and Susceptibility of Geographically Distinct Strains of Aedes aegypti, Aedes albopictus and Culex quinquefasciatus (Diptera: Culicidae to Spondweni Virus.

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    Andrew D Haddow

    2016-10-01

    Full Text Available Zika virus (ZIKV has extended its known geographic distribution to the New World and is now responsible for severe clinical complications in a subset of patients. While substantial genetic and vector susceptibility data exist for ZIKV, less is known for the closest related flavivirus, Spondweni virus (SPONV. Both ZIKV and SPONV have been known to circulate in Africa since the mid-1900s, but neither has been genetically characterized by gene and compared in parallel. Furthermore, the susceptibility of peridomestic mosquito species incriminated or suspected in the transmission of ZIKV to SPONV was unknown.In this study, two geographically distinct strains of SPONV were genetically characterized and compared to nine genetically and geographically distinct ZIKV strains. Additionally, the susceptibility of both SPONV strains was determined in three mosquito species. The open reading frame (ORF of the SPONV 1952 Nigerian Chuku strain, exhibited a nucleotide and amino acid identity of 97.8% and 99.2%, respectively, when compared to the SPONV 1954 prototype South African SA Ar 94 strain. The ORF of the SPONV Chuku strain exhibited a nucleotide and amino acid identity that ranged from 68.3% to 69.0% and 74.6% to 75.0%, respectively, when compared to nine geographically and genetically distinct strains of ZIKV. The ORF of the nine African and Asian lineage ZIKV strains exhibited limited nucleotide divergence. Aedes aegypti, Ae. albopictus and Culex quinquefasciatus susceptibility and dissemination was low or non-existent following artificial infectious blood feeding of moderate doses of both SPONV strains.SPONV and ZIKV nucleotide and amino acid divergence coupled with differences in geographic distribution, ecology and vector species support previous reports that these viruses are separate species. Furthermore, the low degree of SPONV infection or dissemination in Ae. albopictus, Ae. aegypti and Cx. quinquefasciatus following exposure to two

  18. Draft Genome Sequence ofLysinibacillus fusiformisStrain Juneja, a Laboratory-Derived Pathogen ofDrosophila melanogaster.

    Science.gov (United States)

    Smith, Brittny R; Unckless, Robert L

    2018-02-01

    Drosophila melanogaster is a model for the study of innate immunity, yet we have limited knowledge of its natural pathogens. In this study, we sequenced the genome of Lysinibacillus fusiformis strain Juneja, isolated from laboratory fly stocks. As a Gram-positive bacterium with unique peptidoglycans, this strain may provide a new model for pathogen recognition. Copyright © 2018 Smith and Unckless.

  19. Susceptibility of Biomphalaria straminea (Dunker, 1848 from Serra da Mesa Dam, Goiás, Brazil to infection with three strains of Schistosoma mansoni Sambon, 1907

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    Monica Ammon Fernandez

    2002-10-01

    Full Text Available Ecological changes from water resources development projects often affect the epidemiology of water-associated diseases. In order to investigate the occurrence and distribution of freshwater snails of medical and veterinary importance in the area of influence of the Serra da Mesa Hydroelectric a survey has been performed since 1997 and revealed the occurrence of well-established populations of Biomphalaria straminea (Dunker, 1848 in the 8 municipalities surrounding the lake. Areas of epidemiologic risk for schistosomiasis were selected and studies of parasite-mollusc compatibility were undertaken using specimens from 19 populations of B. straminea and 3 strains (CM, EC and PB originally isolated from B. straminea. Among 1,135 specimens used 15 became infected (infection index of 1.3% and 8 populations were susceptible to the schistosome strains: B. straminea from Campinorte (Castelão, susceptible to CM and EC strains, and Planeta Água, EC strain, Colinas (Tocantinzinho river, CM and EC strains, Minaçu (Canabrava river, EC strain, Niquelândia (Codemin, CM and PB strains, and Almas river, CM strain, Uruaçu (touristic area, PB strain and Santa Rita do Novo Destino (Maranhão river, CM and EC strains. These results, associated with marked social and ecological changes occurred, strongly suggest the possibility of B. straminea coming to act as a vector of schistosomiasis in the studied area.

  20. Analysis of adrenocortical secretory responses during acute an prolonged immune stimulation in inflammation-susceptible and -resistant rat strains.

    Science.gov (United States)

    Andersson, I M; Lorentzen, J C; Ericsson-Dahlstrand, A

    2000-11-01

    Endogenous corticosterone secreted during immune challenge restricts the inflammatory process and genetic variations in this neuroendocrine-immune dialogue have been suggested to influence an individuals sensitivity to develop chronic inflammatory disorders. We have tested inflammation-susceptible Dark Agouti (DA) rats and resistant, MHC-identical, PVG.1AV1 rats for their abilities to secrete corticosterone in response to acute challenge with bacterial lipopolysaccharide (LPS) or a prolonged activation of the nonspecific immune system with arthritogenic yeast beta-glucan. Intravenous injection of LPS triggered equipotent secretion of corticosterone in both rat strains. Interestingly, peak concentrations of corticosterone did not differ significantly between the strains. Intradermal injection of beta-glucan caused severe, monophasic, polyarthritis in DA rats while PVG.1AV1 responded with significantly milder joint inflammation. Importantly, serial sampling of plasma from glucan-injected DA and PVG.1AV1 rats did not reveal elevated concentrations of plasma corticosterone at any time from days 1-30 postinjection compared to preinjection values, in spite of the ongoing inflammatory process. Interestingly, adrenalectomized, beta-glucan-challenged DA rats responded with an aggravated arthritic process, indicating an anti-inflammatory role for the basal levels of corticosterone that were detected in intact DA rats challenged with beta-glucan. Moreover, substitution with subcutaneous corticosterone-secreting pellets, yielding moderate stress-levels, significantly attenuated the arthritic response. In contrast, adrenalectomized and glucan-challenged PVG.1AV1 rats did not respond with an elevated arthritic response, suggesting that these rats contain the arthritic process via corticosterone-independent mechanisms. In conclusion, the hypothalamic-pituitary-adrenal axis in both rat strains exhibited strong activation after challenge with LPS. This contrasted to the basal

  1. Whole-genome sequencing of a laboratory-evolved yeast strain

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    Dunham Maitreya J

    2010-02-01

    Full Text Available Abstract Background Experimental evolution of microbial populations provides a unique opportunity to study evolutionary adaptation in response to controlled selective pressures. However, until recently it has been difficult to identify the precise genetic changes underlying adaptation at a genome-wide scale. New DNA sequencing technologies now allow the genome of parental and evolved strains of microorganisms to be rapidly determined. Results We sequenced >93.5% of the genome of a laboratory-evolved strain of the yeast Saccharomyces cerevisiae and its ancestor at >28× depth. Both single nucleotide polymorphisms and copy number amplifications were found, with specific gains over array-based methodologies previously used to analyze these genomes. Applying a segmentation algorithm to quantify structural changes, we determined the approximate genomic boundaries of a 5× gene amplification. These boundaries guided the recovery of breakpoint sequences, which provide insights into the nature of a complex genomic rearrangement. Conclusions This study suggests that whole-genome sequencing can provide a rapid approach to uncover the genetic basis of evolutionary adaptations, with further applications in the study of laboratory selections and mutagenesis screens. In addition, we show how single-end, short read sequencing data can provide detailed information about structural rearrangements, and generate predictions about the genomic features and processes that underlie genome plasticity.

  2. Studies on the susceptibility of ostriches (Struthio camelus to the Indonesian velogenic strain of Newcastle disease virus

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    Darminto

    1998-12-01

    Full Text Available Susceptibility of ostriches (Struthio camelus to the Indonesian velogenic strain of Newcastle disease virus (NDV was evaluated by artificial infection . Twelve - 5 to 6 week old ostriches were divided into 3 groups each containing 4 birds . The first group was inoculated through respiratory system by dropping directly the virus solution into the nostrils, while the second group was inoculated through digestive system by dropping directly the virus solution into the oesophagus, with the dose of infection 106ELDSo (50%-embryo lethal dose per bird . Meanwhile, the third group was treated as uninfected control . All infected birds developed antibody responses, but only two inoculated birds from the first group and two inoculated birds from the second group developed clinical signs of Newcastle disease (ND, with no specific pathological alterations . Infected birds, either sicks or healthy, excreted the challenge viruses through the respiratory system and still be detected up to the end of this experiment, ie . 15 days post-inoculation . The challenge viruses can be re-isolated from the brain, trachea, lungs, heart, liver, spleen, kidneys, small intestine, cecal-tonsil, and proventriculus of the infected birds . This study concludes that: (1 the ostriches are susceptible to the infection of the Indonesian velogenic strain ofNDV; (2 all infected birds developed immune responses, but only half of them develops el jtigi aj i disease ; (3 the infected birds excreted the challenge viruses for a considerable long time which may play role as the Mginiseti.ce ofinfectron the other healthy ostriches ; and (4 the challenge viruses can be re-isolated from various organs of the birds . .

  3. Hydrogen Susceptibility of Pre-strained Type 316L Austenitic Stainless Steels in Aqueous Solutions

    Science.gov (United States)

    Mati, D.; Takasaki, A.; Uematsu, S.

    2017-09-01

    This paper presents the observations made as a result of hydrogen effects in austenitic stainless steels which led to reduction of its original mechanical properties. This paper therefore seeks to understand the mechanisms and effects induced by hydrogen leading to embrittlement. The samples of Type 316L austenitic stainless steel with 20% pre-strain were charged with hydrogen through galvanostastic cathodic loading for 12, 24, 36, and 48 hours respectively, with sample as Cathode and the platinum wire as Anode. Afterwards, they were fractured under tensile test at a slow strain rates. The loss of ductility was evident as observed by the brittle nature of fracture. Small pieces were cut-off near the fracture region and examined through XRD and SEM analysis. The peak widening and slight shifting of the peak positions was observed. The surface cracking was also observed, an indication of surface-induced stresses. The severity of the effects increased with the hydrogen loading time, which is predictive of a real service conditions for austenite steels in aqueous environments.

  4. Polymorphisms in drug-resistant-related genes shared among drug-resistant and pan-susceptible strains of sequence type 10, Beijing family of Mycobacterium tuberculosis

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    Sanjib Mani Regmi

    2015-01-01

    A sequence analysis was performed of 81 previously reported drug-resistant associated genes in multidrug-resistant and pan-susceptible strains of the Beijing family sequence type 10 of MTB. This analysis revealed 10 synonymous and 12 nonsynonymous single nucleotide polymorphisms (SNPs that are shared by all strains under study. One frameshift mutation was also observed to be common to all. These data might be useful in excluding some observed SNPs in drug-resistant-associated genes of MTB Beijing ST 10 when performing genotypic drug susceptibility assay.

  5. Balancing ballistic protection against physiological strain: evidence from laboratory and field trials.

    Science.gov (United States)

    Taylor, Nigel A S; Burdon, Catriona A; van den Heuvel, Anne M J; Fogarty, Alison L; Notley, Sean R; Hunt, Andrew P; Billing, Daniel C; Drain, Jace R; Silk, Aaron J; Patterson, Mark J; Peoples, Gregory E

    2016-02-01

    This project was based on the premise that decisions concerning the ballistic protection provided to defence personnel should derive from an evaluation of the balance between protection level and its impact on physiological function, mobility, and operational capability. Civilians and soldiers participated in laboratory- and field-based studies in which ensembles providing five levels of ballistic protection were evaluated, each with progressive increases in protection, mass (3.4-11.0 kg), and surface-area coverage (0.25-0.52 m(2)). Physiological trials were conducted on volunteers (N = 8) in a laboratory, under hot-dry conditions simulating an urban patrol: walking at 4 km·h(-1) (90 min) and 6 km·h(-1) (30 min or to fatigue). Field-based trials were used to evaluate tactical battlefield movements (mobility) of soldiers (N = 31) under tropical conditions, and across functional tests of power, speed, agility, endurance, and balance. Finally, trials were conducted at a jungle training centre, with soldiers (N = 32) patrolling under tropical conditions (averaging 5 h). In the laboratory, work tolerance was reduced as protection increased, with deep-body temperature climbing relentlessly. However, the protective ensembles could be grouped into two equally stressful categories, each providing a different level of ballistic protection. This outcome was supported during the mobility trials, with the greatest performance decrement evident during fire and movement simulations, as the ensemble mass was increased (-2.12%·kg(-1)). The jungle patrol trials similarly supported this outcome. Therefore, although ballistic protection does increase physiological strain, this research has provided a basis on which to determine how that strain can be balanced against the mission-specific level of required personal protection.

  6. Isolation and Characterization of Agrobacterium Strains from Soil: A Laboratory Capstone Experience

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    Kim R. Finer

    2016-12-01

    Full Text Available In this investigation, the students’ goal was to isolate and characterize Agrobacterium strains from soil. Following selection and enrichment on 1A-t medium, putative Agrobacterium isolates were characterized by Gram stain reaction and biochemical tests. Isolates were further evaluated using polymerase chain reaction (PCR with different primer sets designed to amplify specific regions of bacterial deoxyribonucleic acid (DNA. Primer sets included AGRH to identify isolates that were members of the Rhizobiaceae, BIOVAR1 primers to identify members of Agrobacterium biovar group I, and a third set, VIRG, to determine presence of virG (only present in pathogenic Agrobacterium strains. During the investigation, students applied previously learned techniques including serial dilution, use of selective/differential media, staining protocols, biochemical analysis, molecular analysis via PCR, and electrophoresis. Students also gained practical experience using photo documentation to record data for an eventual mock journal publication of the capstone laboratory experience. Pre- and post-evaluation of class content knowledge related to the techniques, protocols, and learning objectives of these laboratories revealed significant learning gains in the content areas of Agrobacterium–plant interactions (p ≤ 0.001 and molecular biology (p ≤ 0.01. The capstone journal assignment served as the assessment tool to evaluate mastery and application of laboratory technique, the ability to accurately collect and evaluate data, and critical thinking skills associated with experimental troubleshooting and extrapolation. Analysis of journal reports following the capstone experience showed significant improvement in assignment scores (p ≤ 0.0001 and attainment of capstone experience learning outcomes.

  7. Rat Strain Differences in Susceptibility to Alcohol-Induced Chronic Liver Injury and Hepatic Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Sarah M. DeNucci

    2010-01-01

    Full Text Available The finding of more severe steatohepatitis in alcohol fed Long Evans (LE compared with Sprague Dawley (SD and Fisher 344 (FS rats prompted us to determine whether host factors related to alcohol metabolism, inflammation, and insulin/IGF signaling predict proneness to alcohol-mediated liver injury. Adult FS, SD, and LE rats were fed liquid diets containing 0% or 37% (calories ethanol for 8 weeks. Among controls, LE rats had significantly higher ALT and reduced GAPDH relative to SD and FS rats. Among ethanol-fed rats, despite similar blood alcohol levels, LE rats had more pronounced steatohepatitis and fibrosis, higher levels of ALT, DNA damage, pro-inflammatory cytokines, ADH, ALDH, catalase, GFAP, desmin, and collagen expression, and reduced insulin receptor binding relative to FS rats. Ethanol-exposed SD rats had intermediate degrees of steatohepatitis, increased ALT, ADH and profibrogenesis gene expression, and suppressed insulin receptor binding and GAPDH expression, while pro-inflammatory cytokines were similarly increased as in LE rats. Ethanol feeding in FS rats only reduced IL-6, ALDH1–3, CYP2E1, and GAPDH expression in liver. In conclusion, susceptibility to chronic steatohepatitis may be driven by factors related to efficiency of ethanol metabolism and degree to which ethanol exposure causes hepatic insulin resistance and cytokine activation.

  8. In vitro susceptibility of Varroa destructor and Apis mellifera to native strains of Bacillus thuringiensis

    OpenAIRE

    Alquisira-Ramírez, Eva; Paredes-Gonzalez, José; Hernández-Velázquez, Víctor; Ramírez-Trujillo, José; Peña-Chora, Guadalupe

    2014-01-01

    International audience; Fifty-four Bacillus-like strains were isolated from dead Varroa destructor collected in 24 colonies of bees from seven apiaries. The total proteins of 22 isolates were evaluated against adult female V. destructor (100 μg/mL), but only nine caused over 80 % mortality. The LC50 of EA26.1, EA3 and EA11.3 isolates were calculated. The most virulent isolate was EA26.1, as 96.7 % of the mites were killed 36 h after treatment, and the LC50 was 1.50 μg/mL. EA3 produced 93.3 % ...

  9. Gene doctoring: a method for recombineering in laboratory and pathogenic Escherichia coli strains

    Directory of Open Access Journals (Sweden)

    Penn Charles W

    2009-12-01

    to unwanted secondary alterations to the chromosome. Conclusion We have developed a counter-selective recombineering technique for epitope tagging or for deleting genes in E. coli. We have demonstrated the versatility of the technique by modifying the chromosome of the enterohaemorrhagic O157:H7 (EHEC, uropathogenic CFT073 (UPEC, enteroaggregative O42 (EAEC and enterotoxigenic H10407 (ETEC E. coli strains as well as in K-12 laboratory strains.

  10. Gene doctoring: a method for recombineering in laboratory and pathogenic Escherichia coli strains

    Science.gov (United States)

    2009-01-01

    alterations to the chromosome. Conclusion We have developed a counter-selective recombineering technique for epitope tagging or for deleting genes in E. coli. We have demonstrated the versatility of the technique by modifying the chromosome of the enterohaemorrhagic O157:H7 (EHEC), uropathogenic CFT073 (UPEC), enteroaggregative O42 (EAEC) and enterotoxigenic H10407 (ETEC) E. coli strains as well as in K-12 laboratory strains. PMID:20003185

  11. A rapid method for testing in vivo the susceptibility of different strains of Trypanosoma cruzi to active chemotherapeutic agents

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    Leny S. Filardi

    1984-06-01

    Full Text Available A method is described which permits to determine in vivo an in a short period of time (4-6 hours the sensitivity of T. cruzo strains to known active chemotherapeutic agents. By using resistant- and sensitive T. cruzi stains a fairly good correlation was observed between the results obtained with this rapid method (which detects activity against the circulating blood forms and those obtained with long-term schedules which involve drug adminstration for at least 20 consecutive days and a prolonged period of assessment. This method may be used to characterize susceptibility to active drugs used clinically, provide infomation on the specific action against circulating trypomastigotes and screen active compounds. Differences in the natural susceptibility of Trypanosoma cruzi strains to active drugs have been already reported using different criteria, mostly demanding long-term study of the animal (Hauschka, 1949; Bock, Gonnert & Haberkorn, 1969; Brener, Costa & Chiari, 1976; Andrade & Figueira, 1977; Schlemper, 1982. In this paper we report a method which detects in 4-6 hours the effect of drugs on bloodstream forms in mice with established T. cruzi infections. The results obtained with this method show a fairly good correlation with those obtained by prolonged treatment schedules used to assess the action of drugs in experimental Chagas' disease and may be used to study the sensitivity of T. cruzi strains to active drugs.No presente trabalho descreve-se um metodo que permite determinar in vivo e em curto espaço de tempo (4-6 horas a sensibilidade de cepas de T. cruzi a agentes terapeuticos ativos na doença de Chagas. Usando-se cepas sensíveis e resistentes aos medicamentos foi possível observar uma boa correlação entre os resultados obtidos com o método rápido (que detecta atividade contra as formas circulantes do parasita e aqueles obtidos com esquema de acao prolongada que envolve a administração da droga por 20 dias e posterior avalia

  12. Differential susceptibility of inbred mouse strains to chlorine-induced airway fibrosis

    Science.gov (United States)

    Mo, Yiqun; Chen, Jing; Schlueter, Connie F.

    2013-01-01

    Chlorine is a reactive gas that is considered a chemical threat agent. Humans who develop acute lung injury from chlorine inhalation typically recover normal lung function; however, a subset can experience chronic airway disease. To examine pathological changes following chlorine-induced lung injury, mice were exposed to a single high dose of chlorine, and repair of the lung was analyzed at multiple times after exposure. In FVB/NJ mice, chlorine inhalation caused pronounced fibrosis of larger airways that developed by day 7 after exposure and was associated with airway hyperreactivity. In contrast, A/J mice had little or no airway fibrosis and had normal lung function at day 7. Unexposed FVB/NJ mice had less keratin 5 staining (basal cell marker) than A/J mice in large intrapulmonary airways where epithelial repair was poor and fibrosis developed after chlorine exposure. FVB/NJ mice had large areas devoid of epithelium on day 1 after exposure leading to fibroproliferative lesions on days 4 and 7. A/J mice had airways covered by squamous keratin 5-stained cells on day 1 that transitioned to a highly proliferative reparative epithelium by day 4 followed by the reappearance of ciliated and Clara cells by day 7. The data suggest that lack of basal cells in the large intrapulmonary airways and failure to effect epithelial repair at these sites are factors contributing to the development of airway fibrosis in FVB/NJ mice. The observed differences in susceptibility to chlorine-induced airway disease provide a model in which mechanisms and treatment of airway fibrosis can be investigated. PMID:23171502

  13. Virulence genes and antimicrobial susceptibility of lactose-negative and lactose-positive strains of Escherichia coli isolated from pregnant women and neonates.

    Science.gov (United States)

    Kaczmarek, Agnieszka; Skowron, Krzysztof; Budzyńska, Anna; Grudlewska, Katarzyna; Gospodarek-Komkowska, Eugenia

    2017-09-01

    Escherichia coli can cause serious infections in the neonates and pregnant women. Although E. coli is widely studied, E. coli lactose-negative (lac-) strains have been rarely described before. So, the aim of this study was to compare lac- and lactose-positive (lac+) E. coli strains in respect of antimicrobial susceptibility and the frequency of virulence genes (VGs). The study included 58 lac+ and 58 lac- E. coli strains isolated from pregnant women and neonates. Culture and the results of biochemical reactions were conducted for lac- and lac+ E. coli identification and differentiation. Disc diffusion test was performed to study the antimicrobial susceptibility of the isolates, and PCR was used to detect VGs. Resistance to at least one of the tested antibiotics was found among 14 (25.9%) E. coli lac+ and in 26 (44.9%) E. coli lac- strains. Both lac+ and lac- E. coli strains were mostly resistant to ampicillin (22.4 and 39.7%) and ticarcillin (20.7 and 39.7%). None of the tested strains produced extended-spectrum β-lactamases (ESBLs). Genes fimH, fimA, iutA, sfa/foc, neuC, ibeA, and hlyF were detected, respectively, in 96.6, 82.8, 32.8, 24.1, 22.4, 12.1, and 6.9% of lac+ E. coli strains and in 94.8, 86.2, 48.3, 19.0, 8.6, 8.6, and 1.7% of lac- strains. The antimicrobial susceptibility and the pathogenic potential of both tested groups of E. coli strains are similar. Therefore, omitting E. coli lac- strains as a potential etiological agent of infections may pose a threat to the health and life of both mothers and neonates.

  14. Susceptibility and antibody response of the laboratory model zebra finch (Taeniopygia guttata) to West Nile Virus

    Science.gov (United States)

    Hofmeister, Erik K.; Lund, Melissa; Shearn-Bochsler, Valerie I.; Balakrishnan, Christopher N.

    2017-01-01

    Since the introduction of West Nile virus (WNV) into North America in 1999 a number of passerine bird species have been found to play a role in the amplification of the virus. Arbovirus surveillance, observational studies and experimental studies have implicated passerine birds (songbirds, e.g., crows, American robins, house sparrows, and house finches) as significant reservoirs of WNV in North America, yet we lack a tractable passerine animal model for controlled studies of the virus. The zebra finch (Taeniopygia guttata) serves as a model system across a diversity of fields, and here we develop the zebra finch a songbird model for WNV. Like many natural hosts of WNV, we found that zebra finches developed sufficient viremia to serve as a competent host, yet in general resisted mortality from infection. In the Australian zebra finch (AZF) T. g. castanotis, we detected WNV in the majority of sampled tissues by 4 days post injection (dpi). However, WNV was not detected in tissues of sacrificed birds at 14 dpi, shortly after the development of detectable anti-WNV antibodies in the majority of birds indicating successful viral clearance. We compared susceptibility between the two zebra finch subspecies AZF and Timor zebra finch (TZF) T. g. guttata. Compared to AZF, WNV RNA was detected in a larger proportion of challenged TZF and molecular detection of virus in the serum of TZF was significantly higher than in AZF. Given the observed moderate host competence and disease susceptibility, we suggest that zebra finches are appropriate as models for the study of WNV and although underutilized in this respect, may be ideal models for the study of the many diseases carried and transmitted by songbirds.

  15. Susceptibility and Antibody Response of the Laboratory Model Zebra Finch (Taeniopygia guttata to West Nile Virus.

    Directory of Open Access Journals (Sweden)

    Erik K Hofmeister

    Full Text Available Since the introduction of West Nile virus (WNV into North America in 1999 a number of passerine bird species have been found to play a role in the amplification of the virus. Arbovirus surveillance, observational studies and experimental studies have implicated passerine birds (songbirds, e.g., crows, American robins, house sparrows, and house finches as significant reservoirs of WNV in North America, yet we lack a tractable passerine animal model for controlled studies of the virus. The zebra finch (Taeniopygia guttata serves as a model system across a diversity of fields, and here we develop the zebra finch a songbird model for WNV. Like many natural hosts of WNV, we found that zebra finches developed sufficient viremia to serve as a competent host, yet in general resisted mortality from infection. In the Australian zebra finch (AZF T. g. castanotis, we detected WNV in the majority of sampled tissues by 4 days post injection (dpi. However, WNV was not detected in tissues of sacrificed birds at 14 dpi, shortly after the development of detectable anti-WNV antibodies in the majority of birds indicating successful viral clearance. We compared susceptibility between the two zebra finch subspecies AZF and Timor zebra finch (TZF T. g. guttata. Compared to AZF, WNV RNA was detected in a larger proportion of challenged TZF and molecular detection of virus in the serum of TZF was significantly higher than in AZF. Given the observed moderate host competence and disease susceptibility, we suggest that zebra finches are appropriate as models for the study of WNV and although underutilized in this respect, may be ideal models for the study of the many diseases carried and transmitted by songbirds.

  16. Antibiotic resistance in Staphylococcus aureus strains isolated from cows with mastitis in eastern Poland and analysis of susceptibility of resistant strains to alternative nonantibiotic agents: lysostaphin, nisin and polymyxin B.

    Science.gov (United States)

    Szweda, Piotr; Schielmann, Marta; Frankowska, Aneta; Kot, Barbara; Zalewska, Magdalena

    2014-03-01

    The aim of this study was to analyze the resistance of Staphylococcus aureus isolates from bovine mastitis in the eastern part of Poland to a set of 20 antibiotics and three alternative agents: lysostaphin, nisin and polymyxin B. Eighty-six out of 123 examined isolates were susceptible to all 20 tested antibiotics (70%). The highest percentage of resistance was observed in the case of β-lactam antibiotics: amoxicillin (n=22, 17.9%), ampicillin (n=28, 22.8%), penicillin (n=29, 23.6%) and streptomycin (n=13; 10.6%). Twenty-five of the penicillin-resistant strains were found to carry the blaZ gene coding for β-lactamases. Two strains were found to be mecA positive and a few strains were classified as multidrug resistant (MDR), one of them was simultaneously resistant to six antibiotics. All strains, resistant to at least one antibiotic (n=37) and two control strains, were susceptible to lysostaphin with MIC values of 0.008-0.5 µg/ml (susceptibility breakpoint 32 µg/ml). Twenty-one (54%) isolates were susceptible to nisin. The MIC value of this agent for 17 (44%) strains was 51.2 µg/ml and was not much higher than the susceptibility breakpoint value (32 µg/ml). Polymyxin B was able to inhibit the growth of the strains only at a high concentration (32-128 µg/ml). The presented results confirmed the observed worldwide problem of spreading antibiotic resistance among staphylococci isolated from bovine mastitis; on the other hand, we have indicated a high level of bactericidal activity of nisin and especially lysostaphin.

  17. Antimicrobial Susceptibility of Escherichia coli Strains Isolated from Alouatta spp. Feces to Essential Oils

    Directory of Open Access Journals (Sweden)

    Valéria Maria Lara

    2016-01-01

    Full Text Available This study evaluated the in vitro antibacterial activity of essential oils from Lippia graveolens (Mexican oregano, Origanum vulgaris (oregano, Thymus vulgaris (thyme, Rosmarinus officinalis (rosemary, Cymbopogon nardus (citronella, Cymbopogon citratus (lemongrass, and Eucalyptus citriodora (eucalyptus against Escherichia coli (n=22 strains isolated from Alouatta spp. feces. Minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC were determined for each isolate using the broth microdilution technique. Essential oils of Mexican oregano (MIC mean = 1818 μg mL−1; MBC mean = 2618 μg mL−1, thyme (MIC mean = 2618 μg mL−1; MBC mean = 2909 μg mL−1, and oregano (MIC mean = 3418 μg mL−1; MBC mean = 4800 μg mL−1 showed the best antibacterial activity, while essential oils of eucalyptus, rosemary, citronella, and lemongrass displayed no antibacterial activity at concentrations greater than or equal to 6400 μg mL−1. Our results confirm the antimicrobial potential of some essential oils, which deserve further research.

  18. Hybridization of laboratory strains of sibling species A and B of Anopheles quadrimaculatus.

    Science.gov (United States)

    Kaiser, P E; Mitchell, S E; Lanzaro, G C; Seawright, J A

    1988-03-01

    Adult mosquitoes of the Anopheles quadrimaculatus complex were collected from Montgomery County, AL (MON) and Alachua County, FL, (KBG) and laboratory stocks of species A and B were established through a selection procedure employing isofemale lines. Progeny from a cross of species B females to ORL males were usually semisterile females and sterile males. Progeny of the reciprocal cross were also semisterile females and sterile males, but the sex ratio was variable and ranged from normal to no males because of male mortality during the pupal stage. Conspecific crosses between strains from the two locations resulted in fertile offspring. Crosses between the sibling species from the two locations invariably gave semisterile females and sterile males (or lethal effects). This evidence confirmed previous data from hybridization and electrophoretic analyses of field populations indicating that Anopheles quadrimaculatus is a species complex.

  19. Susceptibilities of enterovirus D68, enterovirus 71, and rhinovirus 87 strains to various antiviral compounds.

    Science.gov (United States)

    Smee, Donald F; Evans, W Joseph; Nicolaou, K C; Tarbet, E Bart; Day, Craig W

    2016-07-01

    Compounds were evaluated for antiviral activity in rhabdomyosarcoma (RD) cells against a recent 2014 clinical isolate of enterovirus D68 (EV-D68), a 1962 strain of EV-68D, rhinovirus 87 (RV-87, serologically the same as EV-D68), and enterovirus 71 (EV-71). Test substances included known-active antipicornavirus agents (enviroxime, guanidine HCl, pirodavir, pleconaril, and rupintrivir), nucleobase/nucleoside analogs (3-deazaguanine and ribavirin), and three novel epidithiodiketopiperazines (KCN-2,2'-epi-19, KCN-19, and KCN-21). Of these, rupintrivir was the most potent, with 50% inhibition of viral cytopathic effect (EC50) and 90% inhibition (EC90) of virus yield at 0.0022-0.0053 μM against EV-D68. Enviroxime, pleconaril and the KCN compounds showed efficacy at 0.01-0.3 μM; 3-deazaguanine and pirodavir inhibited EV-D68 at 7-13 μM, and guanidine HCl and ribavirin were inhibitory at 80-135 μM. Pirodavir was active against EV-71 (EC50 of 0.78 μM) but not against RV-87 or EV-D68, and all other compounds were less effective against EV-71 than against RV-87 and EV-D68. The most promising compound inhibiting both virus infections at low concentrations was rupintrivir. Antiviral activity was confirmed for the ten compounds in virus yield reduction (VYR) assays in RD cells, and for enviroxime, guanidine HCl, and pirodavir by cytopathic effect (CPE) assays in A549, HeLa-Ohio-1, and RD cells. These studies may serve as a basis for further pre-clinical discovery of anti-enterovirus inhibitors. Furthermore, the antiviral profiles and growth characteristics observed herein support the assertion that EV-D68 should be classified together with RV-87. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Evaluation of susceptibility of the ZRE1 alloy to hot cracking in conditions of forced strain

    Directory of Open Access Journals (Sweden)

    J. Adamiec

    2010-01-01

    Full Text Available Nowadays, magnesium alloys are used for casting into sand moulds of huge dimensional castings, high-pressure castings and precise casings. In castings of magnesium alloys defects or inconsistencies often appear (like casting misrun, porosities and cracks particularly in the huge dimensional castings. Such defects are mended with the use of padding and welding. The welding techniques can be applied by using weld material consisting of magnesium alloy, as well as for regeneration of alloys after excessive wear. Nevertheless, the number of the repaired castings, which were permitted for use, is not satisfactory for a profitable production. The main reasons for wear are the cracks appearing during welding in brittleness high-temperature range.This work in combination with industrial tests of casting welding show that the causes of high-temperature brittleness are the partial tears of the structure and the hot cracks of both the castings and the welded and padded joints. Such phenomena should be treated as irreversible failures caused by the process of crystallisation that is in the area of co-existence of the solid and liquid structural constituent. The assessment of the resistance to hot fractures was conducted on the basis of the transvarestriant trial. The transvarestriant trial consists in changing of strain during welding It was stated that the range of the high-temperature brittleness is very broad, which significantly limits the application of the welding techniques to join or mend the elements made of alloy ZRE-1. The brittleness is caused mainly by metallurgical factors, i.e., precipitation of inter-metal phases from the solid solution.

  1. Laboratory study of competition between United States strains of Aedes albopictus and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Black, W C; Rai, K S; Turco, B J; Arroyo, D C

    1989-07-01

    Mosquito abatement workers in Houston, Tex., and New Orleans, La., have observed that the recent introduction of Aedes albopictus (Skuse) has been accompanied by a decline and virtual disappearance of Ae. aegypti (L.). This suggests competitive displacement but contradicts the direction of displacement observed in native habitats of Ae. albopictus. The paper reports a series of laboratory studies on competition between U.S. strains of the two species. Larval survivorship, size, and development time were monitored in increasing densities of pure and mixed cultures of the two species under limited and optimal diets. Oviposition preferences were examined by offering gravid females cups containing first or fourth instars of either species. Ethological isolation was studied by simultaneously offering virgin females of one species to males of both species and monitoring courtship behavior as well as rates of oviposition, percentage of hatch, and embryonation. The results of the larval competition studies suggest that interspecific competition increased development time only slightly and had no effect on survival of Ae. albopictus. Competition increased survival in Ae. aegypti. Size of both species was influenced by interspecific competition, but the magnitude and direction of the effect was inconsistent between strains and diets such that neither species emerged consistently larger. The results of the oviposition study indicated a higher fecundity in Ae. aegypti but otherwise demonstrated that both species oviposit without regard to the presence, age, or species of larvae in the oviposition container. The ethological isolation tests demonstrated that Ae. aegypti males were more sexually aggressive than males or Ae. albopictus. However, Ae. albopitus females placed with increasing densities of Ae. aegypti males demonstrated no decrease in rates of oviposition, and eggs laid showed equal rates of hatch and embryonation. In general, the results do not suggest that the U

  2. Susceptibility of Drug-Resistant Clinical Herpes Simplex Virus Type 1 Strains to Essential Oils of Ginger, Thyme, Hyssop, and Sandalwood▿

    Science.gov (United States)

    Schnitzler, Paul; Koch, Christine; Reichling, Jürgen

    2007-01-01

    Acyclovir-resistant clinical isolates of herpes simplex virus type 1 (HSV-1) were analyzed in vitro for their susceptibilities to essential oils of ginger, thyme, hyssop, and sandalwood. All essential oils exhibited high levels of virucidal activity against acyclovir-sensitive strain KOS and acyclovir-resistant HSV-1 clinical isolates and reduced plaque formation significantly. PMID:17353250

  3. Quantitative susceptibility of Streptococcus suis strains isolated from diseased pigs in seven European countries to antimicrobial agents licenced in veterinary medicine

    NARCIS (Netherlands)

    Wisselink, H.J.; Veldman, K.T.; Salmon, S.A.; Mevius, D.J.

    2006-01-01

    The susceptibility of Streptococcus suis strains (n = 384) isolated from diseased pigs in seven European countries to 10 antimicrobial agents was determined. For that purpose a microbroth dilution method was used according to CLSI recommendations. The following antimicrobial agents were tested:

  4. Strain-specific properties and T cells regulate the susceptibility to papilloma induction by Mus musculus papillomavirus 1.

    Science.gov (United States)

    Handisurya, Alessandra; Day, Patricia M; Thompson, Cynthia D; Bonelli, Michael; Lowy, Douglas R; Schiller, John T

    2014-08-01

    The immunocytes that regulate papillomavirus infection and lesion development in humans and animals remain largely undefined. We found that immunocompetent mice with varying H-2 haplotypes displayed asymptomatic skin infection that produced L1 when challenged with 6×1010 MusPV1 virions, the recently identified domestic mouse papillomavirus (also designated "MmuPV1"), but were uniformly resistant to MusPV1-induced papillomatosis. Broad immunosuppression with cyclosporin A resulted in variable induction of papillomas after experimental infection with a similar dose, from robust in Cr:ORL SENCAR to none in C57BL/6 mice, with lesional outgrowth correlating with early viral gene expression and partly with reported strain-specific susceptibility to chemical carcinogens, but not with H-2 haplotype. Challenge with 1×1012 virions in the absence of immunosuppression induced small transient papillomas in Cr:ORL SENCAR but not in C57BL/6 mice. Antibody-induced depletion of CD3+ T cells permitted efficient virus replication and papilloma formation in both strains, providing experimental proof for the crucial role of T cells in controlling papillomavirus infection and associated disease. In Cr:ORL SENCAR mice, immunodepletion of either CD4+ or CD8+ T cells was sufficient for efficient infection and papillomatosis, although deletion of one subset did not inhibit the recruitment of the other subset to the infected epithelium. Thus, the functional cooperation of CD4+ and CD8+ T cells is required to protect this strain. In contrast, C57BL/6 mice required depletion of both CD4+ and CD8+ T cells for infection and papillomatosis, and separate CD4 knock-out and CD8 knock-out C57BL/6 were also resistant. Thus, in C57BL/6 mice, either CD4+ or CD8+ T cell-independent mechanisms exist that can protect this particular strain from MusPV1-associated disease. These findings may help to explain the diversity of pathological outcomes in immunocompetent humans after infection with a specific

  5. Strain-specific properties and T cells regulate the susceptibility to papilloma induction by Mus musculus papillomavirus 1.

    Directory of Open Access Journals (Sweden)

    Alessandra Handisurya

    2014-08-01

    Full Text Available The immunocytes that regulate papillomavirus infection and lesion development in humans and animals remain largely undefined. We found that immunocompetent mice with varying H-2 haplotypes displayed asymptomatic skin infection that produced L1 when challenged with 6×1010 MusPV1 virions, the recently identified domestic mouse papillomavirus (also designated "MmuPV1", but were uniformly resistant to MusPV1-induced papillomatosis. Broad immunosuppression with cyclosporin A resulted in variable induction of papillomas after experimental infection with a similar dose, from robust in Cr:ORL SENCAR to none in C57BL/6 mice, with lesional outgrowth correlating with early viral gene expression and partly with reported strain-specific susceptibility to chemical carcinogens, but not with H-2 haplotype. Challenge with 1×1012 virions in the absence of immunosuppression induced small transient papillomas in Cr:ORL SENCAR but not in C57BL/6 mice. Antibody-induced depletion of CD3+ T cells permitted efficient virus replication and papilloma formation in both strains, providing experimental proof for the crucial role of T cells in controlling papillomavirus infection and associated disease. In Cr:ORL SENCAR mice, immunodepletion of either CD4+ or CD8+ T cells was sufficient for efficient infection and papillomatosis, although deletion of one subset did not inhibit the recruitment of the other subset to the infected epithelium. Thus, the functional cooperation of CD4+ and CD8+ T cells is required to protect this strain. In contrast, C57BL/6 mice required depletion of both CD4+ and CD8+ T cells for infection and papillomatosis, and separate CD4 knock-out and CD8 knock-out C57BL/6 were also resistant. Thus, in C57BL/6 mice, either CD4+ or CD8+ T cell-independent mechanisms exist that can protect this particular strain from MusPV1-associated disease. These findings may help to explain the diversity of pathological outcomes in immunocompetent humans after infection

  6. Susceptibility of Tetranychus urticae Koch to an ethanol extract of Cnidoscolus aconitifolius leaves under laboratory conditions.

    Science.gov (United States)

    Numa, S; Rodríguez, L; Rodríguez, D; Coy-Barrera, E

    2015-01-01

    One of the main pests of commercial rose crops in Colombia is the phytophagous mite Tetranychus urticae Koch. To manage this pest, synthetic chemicals have traditionally been used, some of which are well known to be potentially toxic to the environment and humans. Therefore, alternative strategies for pest management in greenhouse crops have been developed in recent years, including biological control with natural enemies such as parasitoids, predators and entomopathogenic microorganisms as well as chemical control using plant extracts. Such extracts have shown toxicity to insects, which has positioned them as a common alternative in programs of integrated pest management. The objective of this study was to evaluate the effect of an unfractionated ethanolic extract of Cnidoscolus aconitifolius leaves on adult females of T. urticae under laboratory conditions. The extract was chemically characterized by recording its metabolic profile via liquid chromatography coupled to mass spectrometry, along with tentative metabolite identification. The immersion technique and direct application to rose leaves were used to evaluate the effects of seven doses (10-2,000 µg/mL) of the ethanol extract of C. aconitifolius leaves on T. urticae females under laboratory conditions. The mortality and oviposition of individuals were recorded at 24, 48 and 72 h. It was found that the C. aconitifolius leaf extract reduced fertility and increased mortality in a dose-dependent manner. The main metabolites identified included flavonoid- and sesquiterpene-type compounds, in addition to chromone- and xanthone-type compounds as minor constituents with potential acaricidal effects.

  7. Increase in serotype 19A prevalence and amoxicillin non-susceptibility among paediatric Streptococcus pneumoniae isolates from middle ear fluid in a passive laboratory-based surveillance in Spain, 1997-2009

    Directory of Open Access Journals (Sweden)

    Robledo Olga

    2011-09-01

    Full Text Available Abstract Background Conjugate vaccines, such as the 7-valent conjugate vaccine (PCV7, alter serotype nasopharyngeal carriage, potentially increasing cases of otitis media by non-vaccine serotypes. Methods All paediatric middle ear fluid (MEF isolates received in the Spanish Reference Laboratory for Pneumococci through a passive, laboratory-based surveillance system from January 1997 to June 2009 were analysed. Data from 1997 to 2000 were pooled as pre-vaccination period. Trends over time were explored by linear regression analysis. Results A total of 2,077 isolates were analysed: 855 belonging to PCV7 serotypes, 466 to serotype 19A, 215 to serotype 3, 89 to serotype 6A and 452 to other serotypes (2 = 0.944; p 2 = 0.901; p 2 = 0.463; p = 0.030 and other non-PCV7 serotypes (R2 = 0.877; p 2 = 0.311; p = 0.094. Considering all isolates, amoxicillin non-susceptibility showed an increasing trend (R2 = 0.528; p = 0.017. Regarding serotype 19A, increasing trends in non-susceptibility to penicillin (R2 = 0.726; p = 0.001, amoxicillin (R2 = 0.804; p 2 = 0.546; p = 0.005 and erythromycin (R2 = 0.546; p = 0.009 were found, with amoxicillin non-susceptibility firstly detected in 2003 (7.4% and increasing up to 38.0% in 2009. In PCV7 serotypes (which prevalence decreased from 70.7% during 1997-2000 to 10.6% in 2009 amoxicillin non-susceptibility rates showed an increasing trend (R2 = 0.702; p = 0.002. However, overall, amoxicillin non-susceptibility (≈25% in 2008-9 could be mainly attributed to serotype 19A (> 35% isolates since PCV7 strains represented Conclusions In contrast to reports on invasive pneumococcal strains, in MEF isolates the reduction in the prevalence of PCV7 serotypes was not associated with decreases in penicillin/erythromycin non-susceptibility. The high prevalence of serotype 19A among paediatric MEF isolates and the amoxicillin non-susceptibility found in this serotype are worrisome since amoxicillin is the most common antibiotic used

  8. Detection of biofilm production of Yersinia enterocolitica strains isolated from infected children and comparative antimicrobial susceptibility of biofilm versus planktonic forms.

    Science.gov (United States)

    Ioannidis, A; Kyratsa, A; Ioannidou, V; Bersimis, S; Chatzipanagiotou, S

    2014-06-01

    The ability of Yersinia species to produce biofilms has not been hitherto systematically studied, although there is evidence, that Y. enterocolitica is able to form biofilms on inanimate surfaces. The present study aimed to detect the production of biofilms by 60 clinical strains of Y. enterocolitica and to compare the antimicrobial susceptibility of planktonic versus biofilm-forming bacteria. Y. enterocolitica strains were collected from stool and blood cultures collected from β-thalassaemic children, with gastroenteritis and/or septicemia. The isolated bacterial strains were grouped by biotyping and serotyping and the antimicrobial susceptibility of the planktonic forms was investigated by MIC determination. Biofilm formation was detected by the use of silicone disks and for the biofilm forming strains the minimum inhibitory concentration for bacterial regrowth (MICBR) of 11 clinically important antimicrobials was determined. The presence of the waaE, a gene reported to be related with biofilm formation was investigated in all the strains. All of 60 strains were positive for biofilm production by the use of silicone disks. The great majority of the biofilm forms were resistant to all the antimicrobials. In antimicrobial concentrations far higher than the CLSI breakpoints, bacterial regrowth from the biofilms was still possible. None of the strains bore the waaE gene. These results, indicate that biofilm formation by Y. enterocolitica might be an inherent feature. The presence of biofilms increased dramatically the MICBR in all antimicrobials. The way in which biofilms could contribute to Y. enterocolitica pathogenicity in humans is a matter needing further investigation.

  9. Differential susceptibility to cadmium-induced liver and kidney injury in wild and laboratory-bred bank voles Myodes glareolus.

    Science.gov (United States)

    Salińska, Aneta; Włostowski, Tadeusz; Oleńska, Ewa

    2013-08-01

    The objective of the study was to compare the sensitivity of wild and laboratory-bred bank voles to cadmium (Cd)-induced histopathological changes in the liver and kidneys. For 4 weeks, the male bank voles-both wild and laboratory-bred-were provided with diet containing Cd in quantities factors during the development of Cd toxicity in the liver and kidneys-were carried out. Histopathological changes (focal hepatocyte swelling, vacuolation and inflammation [leukocyte infiltration] in the liver, and focal proximal tubule degeneration [including epithelial cell swelling] in the kidneys) occurred only in the wild bank voles fed a diet containing 60 μg Cd/g. There were no differences in concentrations of Cd, MT, GSH, Zn, and Cu in liver and kidney between the respective groups of wild and laboratory-bred animals. However, a decrease of hepatic Fe and lipid peroxidation was observed in the wild voles exhibiting histopathological changes. These data indicate the following: (1) wild bank voles are more susceptible to Cd-induced liver and kidney injury than those bred and raised in the laboratory; (2) the difference in sensitivity may be associated with a distinct decrease of hepatic Fe in response to Cd exposure between the two groups of bank voles; and (3) dietary Cd may produce histopathological changes indirectly through decreasing the hepatic Fe and Fe-dependent oxidative processes. These results also suggest that histopathology in the liver and kidney of wild bank voles living in a contaminated environment may occur at relatively low levels of tissue Cd.

  10. A long-term laboratory test on staining susceptibility of esthetic composite resin materials.

    Science.gov (United States)

    Ardu, Stefano; Braut, Vedrana; Gutemberg, Daniel; Krejci, Ivo; Dietschi, Didier; Feilzer, Albert J

    2010-09-01

    To evaluate the color stability of composite resin types designed for esthetic anterior restorations when continuously exposed to various staining agents. Thirty-six disk-shaped specimens were made of each of 12 composite materials (1 microfilled and 11 hybrid composites). After dry storage at 37 degrees C for 24 hours in an incubator (INP-500, Memmert), the initial color of each specimen was assessed by a calibrated reflectance spectrophotometer (SpectroShade). Specimens were immersed in five staining solutions or dry stored (control). All specimens were kept in an incubator at 37 degrees C for 99 days. Test solutions were changed every 14th day to avoid bacteria or yeast contamination. After 99 days of storage, spectrophotometric measurements were again performed and L*a*b* scores once more recorded to determine the color changes. Wine proved to have the highest staining potential followed by coffee, tea, orange juice, and cola, which had the lowest staining potential. The highest color change measured against a white background was observed for Durafill (Heraeus Kulzer) in wine (DeltaE = 62.3), while the least staining was found for Enamel HFO (Micerium) in cola (DeltaE = 3.5). The highest color change measured against a black background was observed for EsthetX (Dentsply) in wine (DeltaE = 46.0), while the least staining was observed for Enamel HFO in cola (DeltaE = 2.5). Composite staining susceptibility proved to vary among composite structure and brands. Potential discoloration might be limited by dietary restriction based on such in vitro evaluation.

  11. Positional cloning reveals strain-dependent expression of Trim16 to alter susceptibility to bleomycin-induced pulmonary fibrosis in mice.

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    Anguel N Stefanov

    Full Text Available Pulmonary fibrosis is a disease of significant morbidity, with no effective therapeutics and an as yet incompletely defined genetic basis. The chemotherapeutic agent bleomycin induces pulmonary fibrosis in susceptible C57BL/6J mice but not in mice of the C3H/HeJ strain, and this differential strain response has been used in prior studies to map bleomycin-induced pulmonary fibrosis susceptibility loci named Blmpf1 and Blmpf2. In this study we isolated the quantitative trait gene underlying Blmpf2 initially by histologically phenotyping the bleomycin-induced lung disease of sublines of congenic mice to reduce the linkage region to 13 genes. Of these genes, Trim16 was identified to have strain-dependent expression in the lung, which we determined was due to sequence variation in the promoter. Over-expression of Trim16 by plasmid injection increased pulmonary fibrosis, and bronchoalveolar lavage levels of both interleukin 12/23-p40 and neutrophils, in bleomycin treated B6.C3H-Blmpf2 subcongenic mice compared to subcongenic mice treated with bleomycin only, which follows the C57BL/6J versus C3H/HeJ strain difference in these traits. In summary we demonstrate that genetic variation in Trim16 leads to its strain-dependent expression, which alters susceptibility to bleomycin-induced pulmonary fibrosis in mice.

  12. High-throughput behavioral phenotyping of drug and alcohol susceptibility traits in the expanded panel of BXD recombinant inbred strains

    Energy Technology Data Exchange (ETDEWEB)

    Philip, Vivek M [ORNL; Ansah, T [University of Tennessee Health Science Center, Memphis; Blaha, C, [University of Tennessee Health Science Center, Memphis; Cook, Melloni N. [University of Memphis; Hamre, Kristin M. [University of Tennessee Health Science Center, Memphis; Lariviere, William R [University of Pittsburgh; Matthews, Douglas B [Baylor University; Goldowitz, Daniel [University of British Columbia, Vancouver; Chesler, Elissa J [ORNL

    2010-01-01

    Genetic reference populations, particularly the BXD recombinant inbred strains, are a valuable resource for the discovery of the bio-molecular substrates and genetic drivers responsible for trait variation and co- ariation. This approach can be profitably applied in the analysis of susceptibility and mechanisms of drug and alcohol use disorders for which many predisposing behaviors may predict occurrence and manifestation of increased preference for these substances. Many of these traits are modeled by common mouse behavioral assays, facilitating the detection of patterns and sources of genetic co-regulation of predisposing phenotypes and substance consumption. Members of the Tennessee Mouse Genome Consortium have obtained behavioral phenotype data from 260 measures related to multiple behavioral assays across several domains: self-administration, response to, and withdrawal from cocaine, MDMA, morphine and alcohol; novelty seeking; behavioral despair and related neurological phenomena; pain sensitivity; stress sensitivity; anxiety; hyperactivity; and sleep/wake cycles. All traits have been measured in both sexes and the recently expanded panel of 69 additional BXD recombinant inbred strains (N=69). Sex differences and heritability estimates were obtained for each trait, and a comparison of early (N = 32) and recent BXD RI lines was performed. Primary data is publicly available for heritability, sex difference and genetic analyses using www.GeneNetwork.org. These analyses include QTL detection and genetic analysis of gene expression. Stored results from these analyses are available at http://ontologicaldiscovery.org for comparison to other genomic analysis results. Together with the results of related studies, these data form a public resource for integrative systems genetic analysis of neurobehavioral traits.

  13. Innate and Adaptive Immune Response to Pneumonia Virus of Mice in a Resistant and a Susceptible Mouse Strain

    Directory of Open Access Journals (Sweden)

    Ellen R. T. Watkiss

    2013-01-01

    Full Text Available Respiratory syncytial virus (RSV is the leading cause of infant bronchiolitis. The closely related pneumonia virus of mice (PVM causes a similar immune-mediated disease in mice, which allows an analysis of host factors that lead to severe illness. This project was designed to compare the immune responses to lethal and sublethal doses of PVM strain 15 in Balb/c and C57Bl/6 mice. Balb/c mice responded to PVM infection with an earlier and stronger innate response that failed to control viral replication. Production of inflammatory cyto- and chemokines, as well as infiltration of neutrophils and IFN-γ secreting natural killer cells into the lungs, was more predominant in Balb/c mice. In contrast, C57Bl/6 mice were capable of suppressing both viral replication and innate inflammatory responses. After a sublethal infection, PVM-induced IFN-γ production by splenocytes was stronger early during infection and weaker at late time points in C57Bl/6 mice when compared to Balb/c mice. Furthermore, although the IgG levels were similar and the mucosal IgA titres lower, the virus neutralizing antibody titres were higher in C57Bl/6 mice than in Balb/c mice. Overall, the difference in susceptibility of these two strains appeared to be related not to an inherent T helper bias, but to the capacity of the C57Bl/6 mice to control both viral replication and the immune response elicited by PVM.

  14. Increase in serotype 19A prevalence and amoxicillin non-susceptibility among paediatric Streptococcus pneumoniae isolates from middle ear fluid in a passive laboratory-based surveillance in Spain, 1997-2009.

    Science.gov (United States)

    Fenoll, Asunción; Aguilar, Lorenzo; Vicioso, Maria-Dolores; Gimenez, Maria-Jose; Robledo, Olga; Granizo, Juan-Jose

    2011-09-12

    Conjugate vaccines, such as the 7-valent conjugate vaccine (PCV7), alter serotype nasopharyngeal carriage, potentially increasing cases of otitis media by non-vaccine serotypes. All paediatric middle ear fluid (MEF) isolates received in the Spanish Reference Laboratory for Pneumococci through a passive, laboratory-based surveillance system from January 1997 to June 2009 were analysed. Data from 1997 to 2000 were pooled as pre-vaccination period. Trends over time were explored by linear regression analysis. A total of 2,077 isolates were analysed: 855 belonging to PCV7 serotypes, 466 to serotype 19A, 215 to serotype 3, 89 to serotype 6A and 452 to other serotypes ( 35% isolates) since PCV7 strains represented < 11% of total clinical isolates. In contrast to reports on invasive pneumococcal strains, in MEF isolates the reduction in the prevalence of PCV7 serotypes was not associated with decreases in penicillin/erythromycin non-susceptibility. The high prevalence of serotype 19A among paediatric MEF isolates and the amoxicillin non-susceptibility found in this serotype are worrisome since amoxicillin is the most common antibiotic used in the treatment of acute otitis media. These data suggest that non-PCV7 serotypes (mainly serotype 19A followed by serotypes 3 and 6A) are important etiological agents of acute otitis media and support the added value of the broader coverage of the new 13-valent conjugate vaccine.

  15. Susceptibility of Representative Great Lakes Fish Species to the North Carolina Strain of Spring Viremia of Carp Virus (SVCV).

    Science.gov (United States)

    Boonthai, Traimat; Loch, Thomas P; Standish, Isaac; Faisal, Mohamed

    2017-12-01

    Spring viremia of carp virus (SVCV) is a notifiable pathogen of the World Organization of Animal Health. Since SVCV was isolated in Lake Ontario in 2007, concern has grown about its spread in the Great Lakes basin and its potential negative impacts on fish species of importance in stock enhancement programs basinwide. The susceptibility of representative fish species from the families Cyprinidae (Fathead Minnow Pimephales promelas, Golden Shiner Notemigonus crysoleucas, Spotfin Shiner Cyprinella spiloptera, and Creek Chub Semotilus atromaculatus), Centrarchidae (Largemouth Bass Micropterus salmoides), Percidae (Walleye Sander vitreus), Salmonidae (Rainbow Trout Oncorhynchus mykiss), and Esocidae (Muskellunge Esox masquinongy) to SVCV was evaluated by experimental infection under laboratory conditions. Morbidity and mortality were recorded, and virus re-isolation, seminested reverse transcription PCR, and histopathological assessments were performed. Using intraperitoneal (i.p.) injection, Fathead Minnows and Golden Shiners were highly susceptible to SVCV (40-70% mortality). All dead or moribund and apparently healthy surviving Fathead Minnows and Golden Shiners were SVCV positive. The SVCV was also detected in challenged but healthy Spotfin Shiners (30%) and Creek Chub (5%). However, noncyprinid species exhibited no morbidity or mortality and were free of SVCV following an observation period of 30 d. In a follow-up experimental challenge, Fathead Minnows and Golden Shiners were SVCV challenged at 10 3 and 10 5 PFU/mL by means of waterborne immersion. After immersion, Fathead Minnows and Golden Shiners exhibited characteristic SVCV disease signs, but mortality was less (30% and 10% mortality, respectively) than that in fish with i.p. injections. The SVCV was detected in all mortalities and a subset of healthy Fathead Minnows and Golden Shiners. Necrotic changes were observed in the kidneys, liver, spleen, ovaries, and heart, and other histopathological lesions also

  16. Laboratory Evolution of a Biotin-Requiring Saccharomyces cerevisiae Strain for Full Biotin Prototrophy and Identification of Causal Mutations.

    Science.gov (United States)

    Bracher, Jasmine M; de Hulster, Erik; Koster, Charlotte C; van den Broek, Marcel; Daran, Jean-Marc G; van Maris, Antonius J A; Pronk, Jack T

    2017-08-15

    Biotin prototrophy is a rare, incompletely understood, and industrially relevant characteristic of Saccharomyces cerevisiae strains. The genome of the haploid laboratory strain CEN.PK113-7D contains a full complement of biotin biosynthesis genes, but its growth in biotin-free synthetic medium is extremely slow (specific growth rate [μ] ≈ 0.01 h -1 ). Four independent evolution experiments in repeated batch cultures and accelerostats yielded strains whose growth rates (μ ≤ 0.36 h -1 ) in biotin-free and biotin-supplemented media were similar. Whole-genome resequencing of these evolved strains revealed up to 40-fold amplification of BIO1 , which encodes pimeloyl-coenzyme A (CoA) synthetase. The additional copies of BIO1 were found on different chromosomes, and its amplification coincided with substantial chromosomal rearrangements. A key role of this gene amplification was confirmed by overexpression of BIO1 in strain CEN.PK113-7D, which enabled growth in biotin-free medium (μ = 0.15 h -1 ). Mutations in the membrane transporter genes TPO1 and/or PDR12 were found in several of the evolved strains. Deletion of TPO1 and PDR12 in a BIO1 -overexpressing strain increased its specific growth rate to 0.25 h -1 The effects of null mutations in these genes, which have not been previously associated with biotin metabolism, were nonadditive. This study demonstrates that S. cerevisiae strains that carry the basic genetic information for biotin synthesis can be evolved for full biotin prototrophy and identifies new targets for engineering biotin prototrophy into laboratory and industrial strains of this yeast. IMPORTANCE Although biotin (vitamin H) plays essential roles in all organisms, not all organisms can synthesize this vitamin. Many strains of baker's yeast, an important microorganism in industrial biotechnology, contain at least some of the genes required for biotin synthesis. However, most of these strains cannot synthesize biotin at all or do so at rates that are

  17. Distribution of Strain Type and Antimicrobial Susceptibility of Escherichia coli Isolates Causing Meningitis in a Large Urban Setting in Brazil

    Science.gov (United States)

    Berman, Hillary; Barberino, Maria Goreth; Moreira, Edson Duarte; Riley, Lee

    2014-01-01

    The clinical management of meningitis caused by Escherichia coli is greatly complicated when the organism becomes resistant to broad-spectrum antibiotics. We sought to characterize the antimicrobial susceptibilities, sequence types (ST), and presence of known drug resistance genes of E. coli isolates that caused meningitis between 1996 and 2011 in Salvador, Brazil. We then compared these findings to those for E. coli isolates from community-acquired urinary tract infections (UTI) that occurred during the same time period and in the same city. We found that 19% of E. coli isolates from cases of meningitis and less than 1% of isolates from UTI were resistant to third-generation cephalosporins. The sequence types of E. coli isolates from cases of meningitis included ST131, ST69, ST405, and ST62, which were also found among isolates from UTI. Additionally, among the E. coli isolates that were resistant to third-generation cephalosporins, we found genes that encode the extended-spectrum beta-lactamases CTX-M-2, CTX-M-14, and CTX-M-15. These observations demonstrate that compared to E. coli strains isolated from cases of community-acquired UTI, those isolated from cases of meningitis are more resistant to third-generation cephalosporins, even though the same sequence types are shared between the two forms of extraintestinal infections. PMID:24523478

  18. Distribution of strain type and antimicrobial susceptibility of Escherichia coli isolates causing meningitis in a large urban setting in Brazil.

    Science.gov (United States)

    Berman, Hillary; Barberino, Maria Goreth; Moreira, Edson Duarte; Riley, Lee; Reis, Joice N

    2014-05-01

    The clinical management of meningitis caused by Escherichia coli is greatly complicated when the organism becomes resistant to broad-spectrum antibiotics. We sought to characterize the antimicrobial susceptibilities, sequence types (ST), and presence of known drug resistance genes of E. coli isolates that caused meningitis between 1996 and 2011 in Salvador, Brazil. We then compared these findings to those for E. coli isolates from community-acquired urinary tract infections (UTI) that occurred during the same time period and in the same city. We found that 19% of E. coli isolates from cases of meningitis and less than 1% of isolates from UTI were resistant to third-generation cephalosporins. The sequence types of E. coli isolates from cases of meningitis included ST131, ST69, ST405, and ST62, which were also found among isolates from UTI. Additionally, among the E. coli isolates that were resistant to third-generation cephalosporins, we found genes that encode the extended-spectrum beta-lactamases CTX-M-2, CTX-M-14, and CTX-M-15. These observations demonstrate that compared to E. coli strains isolated from cases of community-acquired UTI, those isolated from cases of meningitis are more resistant to third-generation cephalosporins, even though the same sequence types are shared between the two forms of extraintestinal infections.

  19. In vitro susceptibility and eradication of Chlamydia pneumoniae cardiovascular strains from coronary artery endothelium and smooth muscle cells.

    Science.gov (United States)

    Gieffers, J; Solbach, W; Maass, M

    2001-01-01

    Recovery of viable Chlamydia pneumoniae from atheromas of coronary heart diseases patients has initiated pilot studies to eradicate C. pneumoniae from vascular tissue by antibiotic treatment. To provide data for the selection of effective antibiotics, we investigated the in vitro activity of anti-chlamydial antibiotics to eliminate vascular strains of C. pneumoniae from coronary endothelial and smooth muscle cells, celltypes that are involved in the pathogenesis of atherosclerosis. The susceptibility of the obligate intracellular chlamydiae was studied in primary coronary endothelial cells, smooth muscle cells and immortalized epithelial cells. Minimal inhibitory concentrations (MICs) were determined for ofloxacin, levofloxacin, trovafloxacin, moxifloxacin, erythromycin, azithromycin, roxithromycin, rifapentin and rifampin. In vitro, rifampin was the most effective drug overall. Moxifloxacin and trovafloxacin were as effective as the macrolides of which roxithromycin was the most active one. Actively replicating C. pneumoniae can be eliminated in vitro from cell types, involved in the pathogenesis of atherosclerosis by various antibiotics. These data provide an experimental background for the selection of antibiotics in clinical eradication studies and will help to assess the potential success of prevention and eradication therapies.

  20. Studies in Phylogeny, Development of Rapid IdentificationMethods, Antifungal Susceptibility, and Growth Rates of Clinical Strains of Sporothrix schenckii Complex in Japan.

    Science.gov (United States)

    Suzuki, Rumi; Yikelamu, Alimu; Tanaka, Reiko; Igawa, Ken; Yokozeki, Hiroo; Yaguchi, Takashi

    2016-01-01

    Sporotrichosis is a fungal infection caused by the Sporothrix species, which have distinct virulence profiles and geographic distributions. We performed a phylogenetic study in strains morphologically identified as Sporothrix schenckii from clinical specimens in Japan, which were preserved at the Medical Mycology Research Center, Chiba University. In addition, we examined the in vitro antifungal susceptibility and growth rate to evaluate their physiological features. Three hundred strains were examined using sequence analysis of the partial calmodulin gene, or polymerase chain reaction(PCR)method using newly designed species-specific primers; 291 strains were Sporothrix globosa and 9 strains were S. schenckii sensu stricto (in narrow sense, s. s.). S. globosa strains were further clustered into two subclades, and S. schenckii s. s. strains were divided into three subclades. In 38 strains of S. globosa for which antifungal profiles were determined, 4 strains (11%) showed high minimal inhibitory concentration (MIC) value for itraconazole. All tested strains of S. schenckii s. s. and S. globosa showed low sensitivity for amphotericin B. These antifungals are used for treatment of sporotrichosis when infection is severe. S. schenckii s. s. grew better than S. globosa; wherein S. globosa showed restricted growth at 35℃ and did not grow at 37℃. Our molecular data showed that S. globosa is the main causal agent of sporotrichosis in Japan. It is important to determine the antifungal profiles of each case, in addition to accurate species-level identification, to strategize the therapy for sporotrichosis.

  1. The effect of larval nutritional deprivation on the life history and DDT resistance phenotype in laboratory strains of the malaria vector Anopheles arabiensis

    Science.gov (United States)

    2013-01-01

    Background Anopheles arabiensis is a major malaria vector in Africa. It thrives in agricultural areas and has been associated with increased malaria incidence in areas under rice and maize cultivation. This effect may be due to increased adult size and abundance as a consequence of optimal larval nutrition. The aim of this study was to examine the effect of larval nutrition on the life history and expression of insecticide resistance in adults of laboratory reared An. arabiensis. Methods Larvae drawn from an insecticide susceptible An. arabiensis strain (SENN) as well as a DDT-resistant strain (SENN-DDT) were subjected to three fasting regimes: 1 mg of food per larva offered once per day, once every second day and once every third day. Control cohorts included larvae offered 1 mg food thrice per day. The rate of larval development was compared between matched cohorts from each strain as well as between fasted larvae and their respective controls. The expression of DDT resistance/tolerance in adults was compared between the starved cohorts and their controls by strain. Factors potentially affecting variation in DDT resistance/tolerance were examined including: adult body size (wing length), knock-down resistance (kdr) status and levels of detoxification enzyme activity. Results and conclusion Anopheles arabiensis larval development is prolonged by nutrient deprivation and adults that eclose from starved larvae are smaller and less tolerant to DDT intoxication. This effect on DDT tolerance in adults is also associated with reduced detoxification enzyme activity. Conversely, well fed larvae develop comparatively quickly into large, more DDT tolerant (SENN) or resistant (SENN-DDT) adults. This is important in those instances where cereal farming is associated with increased An. arabiensis transmitted malaria incidence, because large adult females with high teneral reserves and decreased susceptibility to insecticide intoxication may also prove to be more

  2. The effect of larval nutritional deprivation on the life history and DDT resistance phenotype in laboratory strains of the malaria vector Anopheles arabiensis.

    Science.gov (United States)

    Oliver, Shüné V; Brooke, Basil D

    2013-02-01

    Anopheles arabiensis is a major malaria vector in Africa. It thrives in agricultural areas and has been associated with increased malaria incidence in areas under rice and maize cultivation. This effect may be due to increased adult size and abundance as a consequence of optimal larval nutrition. The aim of this study was to examine the effect of larval nutrition on the life history and expression of insecticide resistance in adults of laboratory reared An. arabiensis. Larvae drawn from an insecticide susceptible An. arabiensis strain (SENN) as well as a DDT-resistant strain (SENN-DDT) were subjected to three fasting regimes: 1 mg of food per larva offered once per day, once every second day and once every third day. Control cohorts included larvae offered 1 mg food thrice per day. The rate of larval development was compared between matched cohorts from each strain as well as between fasted larvae and their respective controls. The expression of DDT resistance/tolerance in adults was compared between the starved cohorts and their controls by strain. Factors potentially affecting variation in DDT resistance/tolerance were examined including: adult body size (wing length), knock-down resistance (kdr) status and levels of detoxification enzyme activity. Anopheles arabiensis larval development is prolonged by nutrient deprivation and adults that eclose from starved larvae are smaller and less tolerant to DDT intoxication. This effect on DDT tolerance in adults is also associated with reduced detoxification enzyme activity. Conversely, well fed larvae develop comparatively quickly into large, more DDT tolerant (SENN) or resistant (SENN-DDT) adults. This is important in those instances where cereal farming is associated with increased An. arabiensis transmitted malaria incidence, because large adult females with high teneral reserves and decreased susceptibility to insecticide intoxication may also prove to be more efficient malaria vectors. In general, larval

  3. The effect of larval nutritional deprivation on the life history and DDT resistance phenotype in laboratory strains of the malaria vector Anopheles arabiensis

    Directory of Open Access Journals (Sweden)

    Oliver Shüné V

    2013-02-01

    Full Text Available Abstract Background Anopheles arabiensis is a major malaria vector in Africa. It thrives in agricultural areas and has been associated with increased malaria incidence in areas under rice and maize cultivation. This effect may be due to increased adult size and abundance as a consequence of optimal larval nutrition. The aim of this study was to examine the effect of larval nutrition on the life history and expression of insecticide resistance in adults of laboratory reared An. arabiensis. Methods Larvae drawn from an insecticide susceptible An. arabiensis strain (SENN as well as a DDT-resistant strain (SENN-DDT were subjected to three fasting regimes: 1 mg of food per larva offered once per day, once every second day and once every third day. Control cohorts included larvae offered 1 mg food thrice per day. The rate of larval development was compared between matched cohorts from each strain as well as between fasted larvae and their respective controls. The expression of DDT resistance/tolerance in adults was compared between the starved cohorts and their controls by strain. Factors potentially affecting variation in DDT resistance/tolerance were examined including: adult body size (wing length, knock-down resistance (kdr status and levels of detoxification enzyme activity. Results and conclusion Anopheles arabiensis larval development is prolonged by nutrient deprivation and adults that eclose from starved larvae are smaller and less tolerant to DDT intoxication. This effect on DDT tolerance in adults is also associated with reduced detoxification enzyme activity. Conversely, well fed larvae develop comparatively quickly into large, more DDT tolerant (SENN or resistant (SENN-DDT adults. This is important in those instances where cereal farming is associated with increased An. arabiensis transmitted malaria incidence, because large adult females with high teneral reserves and decreased susceptibility to insecticide intoxication may also

  4. A comparative study of P450 gene expression in field and laboratory Musca domestica L. strains

    DEFF Research Database (Denmark)

    Højland, Dorte Heidi; Vagn Jensen, Karl-Martin; Kristensen, Michael

    2014-01-01

    unselected strains: a multiresistant strain (791a), a neonicotinoid-resistant strain (766b) and a new field strain (845b). RESULTS CYP4G2 was highly expressed throughout the range of strains and proved to be the one of the most interesting expression profiles of all P450s analysed. CYP6G4 was expressed up...... that CYP6G4 is a major insecticide resistance gene involved in neonicotinoid resistance. © 2013 Society of Chemical Industry...

  5. TfoX-based genetic mapping identifies Vibrio fischeri strain-level differences and reveals a common lineage of laboratory strains.

    Science.gov (United States)

    Brooks, John F; Gyllborg, Mattias C; Kocher, Acadia A; Markey, Laura E H; Mandel, Mark J

    2015-03-01

    Bacterial strain variation exists in natural populations of bacteria and can be generated experimentally through directed or random mutation. The advent of rapid and cost-efficient whole-genome sequencing has facilitated strain-level genotyping. Even with modern tools, however, it often remains a challenge to map specific traits to individual genetic loci, especially for traits that cannot be selected under culture conditions (e.g., colonization level or pathogenicity). Using a combination of classical and modern approaches, we analyzed strain-level variation in Vibrio fischeri and identified the basis by which some strains lack the ability to utilize glycerol as a carbon source. We proceeded to reconstruct the lineage of the commonly used V. fischeri laboratory strains. Compared to the wild-type ES114 strain, we identify in ES114-L a 9.9-kb deletion with endpoints in tadB2 and glpF; restoration of the missing portion of glpF restores the wild-type phenotype. The widely used strains ESR1, JRM100, and JRM200 contain the same deletion, and ES114-L is likely a previously unrecognized intermediate strain in the construction of many ES114 derivatives. ES114-L does not exhibit a defect in competitive squid colonization but ESR1 does, demonstrating that glycerol utilization is not required for early squid colonization. Our genetic mapping approach capitalizes on the recently discovered chitin-based transformation pathway, which is conserved in the Vibrionaceae; therefore, the specific approach used is likely to be useful for mapping genetic traits in other Vibrio species. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Antibiotic resistance, ability to form biofilm and susceptibility to copper alloys of selected staphylococcal strains isolated from touch surfaces in Polish hospital wards.

    Science.gov (United States)

    Różańska, Anna; Chmielarczyk, Agnieszka; Romaniszyn, Dorota; Bulanda, Małgorzata; Walkowicz, Monika; Osuch, Piotr; Knych, Tadeusz

    2017-01-01

    Despite the employment of sanitary regimes, contact transmission of the aetiological agents of hospital infections is still exceedingly common. The issue of microbe transmission becomes particularly important when facing multidrug-resistant microorganisms such as methicillin-resistant staphylococci. In the case of deficiencies in cleaning and disinfection procedures, hospital equipment made of copper alloys can play an important role, complementing traditional hospital hygiene procedures. The objective of this study was to characterize staphylococcal strains isolated from touch surfaces in Polish hospital wards in terms of their drug resistance, ability to form biofilm and susceptibility to antimicrobial activity of copper alloys. The materials for the study were 95 staphylococcal strains isolated from touch surfaces in 13 different hospital wards from Małopolska province (the south of Poland). Phenotypic and genotypic antibiotic resistance were checked for erythromycin, clindamycin, gentamycin, ciprofloxacin, trimethoprim/sulfamethoxazole and mupirocin. Biofilm formation ability for the tested strains was checked with the use of culture on Congo red agar. Susceptibility to copper, tin bronze, brass and new silver was tested using a modification of the Japanese standard. Over 67% of the analysed staphylococcal strains were methicillin-resistant (MR). Four strains were resistant to all of the tested antibiotics, and 14 were resistant to all except mupirocin. Strains classified as MR had significantly increased resistance to the remaining antibiotic groups. About one-third of the analysed strains revealed biofilm-forming ability. Among the majority of species, biofilm-forming and non-biofilm-forming strains were distributed evenly; in the case of S. haemolyticus only, negative strains accounted for 92.8%. Susceptibility to copper alloys was different between strains and rather lower than in the case of the SA strain selected for comparison. Coagulase

  7. Multiple drug-susceptibility screening in Mycobacterium bovis: new nucleotide polymorphisms in the embB gene among ethambutol susceptible strains

    Directory of Open Access Journals (Sweden)

    Cinzia Marianelli

    2015-04-01

    Conclusion: All M. bovis isolates were sensitive to the most common antituberculosis drugs used for treatment. There was a good agreement between the d-REMA assay and the agar based reference method. Among ethambutol susceptible isolates, four new embB mutations were found.

  8. Antifungal susceptibility testing of Aspergillus species complex in the Clinical Laboratory: how to do it, when to do it, and how to interpret it

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    Esther Manso

    2014-12-01

    Full Text Available The emergence of drug resistance in fungal pathogens has a profound impact on human health given limited number of antifungal drugs. Antifungal resistance in Aspergillus spp. infection can be encountered in the antifungal drug-exposed patient due to selection of intrinsically resistant species or isolates with acquired resistance belonging to species that are normally susceptible. Resistance to triazoles is not common in Aspergillus spp., however, triazole resistance in A. fumigatus appears to be increasing in several European countries in recent years and can be clinically relevant. The Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing have developed breakpoints and epidemiological cutoff values that are now established for Aspergillus spp. Clinical microbiology laboratories will be employed commercial susceptibility assays, rather than reference broth microdilution methods and comparative studies are particularly important.

  9. Genetic clustering of Borna disease virus natural animal isolates, laboratory and vaccine strains strongly reflects their regional geographical origin.

    Science.gov (United States)

    Kolodziejek, Jolanta; Dürrwald, Ralf; Herzog, Sibylle; Ehrensperger, Felix; Lussy, Helga; Nowotny, Norbert

    2005-02-01

    The aim of this study was to gain more detailed insights into the genetic evolution and variability of Borna disease virus (BDV). Phylogenetic analyses were performed on field viruses originating from naturally infected animals, the BDV vaccine strain 'Dessau', four widely used laboratory strains and the novel BDV subtype No/98. Four regions of the BDV genome were analysed: the complete p40, p10 and p24 genes and the 5'-untranslated region of the X/P transcript. BDV isolates from the same geographical area exhibited a clearly higher degree of identity to each other than to BDV isolates from other regions, independent of host species and year of isolation. Five different clusters could be established within endemic areas, corresponding to the geographical regions from which the viruses originated: (i) a Swiss, Austrian and Liechtenstein Rhine valley group, related closely to the geographically bordering Baden-Wurttemberg and Bavaria II group (ii) in the western part of Germany; (iii) a third group, called Bavaria I group, limited in occurrence to Bavaria; (iv) a southern Saxony-Anhalt and bordering northern Saxony group, bound to the territories of these federal states in the eastern part of Germany; and (v) a mixed group, consisting of samples from different areas of Germany; however, these were mainly from the federal states of Thuringia and Lower Saxony. The laboratory strains and the vaccine strain clustered within these groups according to their geographical origins. All field and laboratory strains, as well as the vaccine strain, clearly segregated from the recently described and highly divergent BDV strain No/98, which originated from an area in Austria where Borna disease is not endemic.

  10. Protein abundances can distinguish between naturally-occurring and laboratory strains of Yersinia pestis, the causative agent of plague.

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    Eric D Merkley

    Full Text Available The rapid pace of bacterial evolution enables organisms to adapt to the laboratory environment with repeated passage and thus diverge from naturally-occurring environmental ("wild" strains. Distinguishing wild and laboratory strains is clearly important for biodefense and bioforensics; however, DNA sequence data alone has thus far not provided a clear signature, perhaps due to lack of understanding of how diverse genome changes lead to convergent phenotypes, difficulty in detecting certain types of mutations, or perhaps because some adaptive modifications are epigenetic. Monitoring protein abundance, a molecular measure of phenotype, can overcome some of these difficulties. We have assembled a collection of Yersinia pestis proteomics datasets from our own published and unpublished work, and from a proteomics data archive, and demonstrated that protein abundance data can clearly distinguish laboratory-adapted from wild. We developed a lasso logistic regression classifier that uses binary (presence/absence or quantitative protein abundance measures to predict whether a sample is laboratory-adapted or wild that proved to be ~98% accurate, as judged by replicated 10-fold cross-validation. Protein features selected by the classifier accord well with our previous study of laboratory adaptation in Y. pestis. The input data was derived from a variety of unrelated experiments and contained significant confounding variables. We show that the classifier is robust with respect to these variables. The methodology is able to discover signatures for laboratory facility and culture medium that are largely independent of the signature of laboratory adaptation. Going beyond our previous laboratory evolution study, this work suggests that proteomic differences between laboratory-adapted and wild Y. pestis are general, potentially pointing to a process that could apply to other species as well. Additionally, we show that proteomics datasets (even archived data

  11. Central nervous system Toll-like receptor expression in response to Theiler's murine encephalomyelitis virus-induced demyelination disease in resistant and susceptible mouse strains

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    Turrin Nicolas P

    2008-12-01

    Full Text Available Abstract Background In immunopathological diseases, such as multiple sclerosis (MS, genetic and environmental factors that contribute to the initiation and progression of the disease are often discussed. The Theiler murine encephalomyelitis virus-induced demyelination disease (TMEV-IDD model used to study MS reflects this: genetically susceptible mice infected intra-cerebrally with TMEV develop a chronic demyelination disease. TMEV-IDD can be induced in resistant mouse strains by inducing innate immunity with lipopolysaccharide (LPS. Interestingly, Toll-like receptor 4 (TLR4 is the cognate receptor for LPS and its activation can induces up-regulation of other TLRs, such as TLR7 (the receptor for TMEV and 9, known to be involved in autoimmunity. Up-regulation of TLRs could be involved in precipitating an autoimmune susceptible state. Consequently, we looked at TLR expression in the susceptible (SJL/J and resistant (C57BL/6 strains of mice infected with TMEV. The resistant mice were induced to develop TMEV-IDD by two LPS injections following TMEV infection. Results Both strains were found to up-regulate multiple TLRs (TLR2, 7 and 9 following the TMEV infection. Expression of these TLRs and of viral mRNA was significantly greater in infected SJL/J mice. The susceptible SJL/J mice showed up-regulation of TLR3, 6 and 8, which was not seen in C57BL/6 mice. Conclusion Expression of TLRs by susceptible mice and the up-regulation of the TLRs in resistant mice could participate in priming the mice toward an autoimmune state and develop TMEV-IDD. This could have implications on therapies that target TLRs to prevent the emergence of conditions such as MS in patients at risk for the disease.

  12. A descriptive analysis of the antimicrobial susceptibility of mastitis-causing bacteria isolated from samples submitted to commercial diagnostic laboratories in New Zealand (2003-2006).

    Science.gov (United States)

    Petrovski, K R; Laven, R A; Lopez-Villalobos, N

    2011-03-01

    To describe the antimicrobial susceptibility of mastitis-causing bacteria isolated from milk samples submitted to commercial laboratories over a period of 40 months. The records of reported results of milk samples submitted by veterinary practitioners to five commercial veterinary laboratories in the North and South Islands of New Zealand, between August 2003 and December 2006 were reviewed. Logistic regression was used to analyse the effect of year, island, and the interaction of year and antimicrobial on the probability of antimicrobial susceptibility for each pathogen and antimicrobial combination, where the causative bacteria had >1,000 susceptibility tests in total and the antimicrobials was tested on >500 isolates. A total of 9,262 isolates were included in this study, with an average of nearly seven susceptibility tests per isolate, totalling 62,918 tests. Streptococcus uberis isolates demonstrated high overall susceptibility (>90.0%) to the majority of antimicrobial agents except ampicillin (81.7%), lincomycin (85.3%), trimethoprim/sulphonamide combination (88.6%), and, as expected, aminoglycosides (penicillin (73.1%), and streptomycin (71.7%). No antimicrobial was effective against all Staph. aureus isolates. Minor changes were found in the overall susceptibility of the main mastitis-causing bacteria between 2003 and 2006. The antimicrobial agents intended for treatment of bovine mastitis currently available in New Zealand generally demonstrated good in-vitro efficacy against streptococci and staphylococci, with the exception of aminoglycosides. Analysis of the results of antimicrobial susceptibility of bacterial isolates from milk samples from dairy cows in New Zealand provides useful data for surveillance purposes, and a baseline for identifying changes in antimicrobial sensitivity in this population. However, the variation in antimicrobial susceptibility between individual isolates means that these data are of limited value when determining treatment of

  13. Larval and juvenile Pacific herring Clupea pallasii are not susceptible to infectious hematopoietic necrosis under laboratory conditions

    Science.gov (United States)

    Hart, L.M.; Traxler, G.S.; Garver, K.A.; Richard, J.; Gregg, J.L.; Grady, C.A.; Kurath, G.; Hershberger, P.K.

    2011-01-01

    Infectious hematopoietic necrosis (IHN) leads to periodic epidemics among certain wild and farmed fish species of the Northeast (NE) Pacific. The source of the IHN virus (IHNV) that initiates these outbreaks remains unknown; however, a leading hypothesis involves viral persistence in marine host species such as Pacific herring Clupea pallasii. Under laboratory conditions we exposed specific pathogen-free (SPF) larval and juvenile Pacific herring to 103 to 104 plaque-forming units (pfu) of IHNV ml–1 by waterborne immersion. Cumulative mortalities among exposed groups were not significantly different from those of negative control groups. After waterborne exposure, IHNV was transiently recovered from the tissues of larvae but absent in tissues of juveniles. Additionally, no evidence of viral shedding was detected in the tank water containing exposed juveniles. After intraperitoneal (IP) injection of IHNV in juvenile herring with 103 pfu, IHNV was recovered from the tissues of sub-sampled individuals for only the first 5 d post-exposure. The lack of susceptibility to overt disease and transient levels of IHNV in the tissues of exposed fish indicate that Pacific herring do not likely serve a major epizootiological role in perpetuation of IHNV among free-ranging sockeye salmon Oncorhynchus nerka and farmed Atlantic salmon Salmo salar in the NE Pacific.

  14. Susceptibility of S. pneumoniae to various antibiotics among strains isolated from patients and healthy carriers in different regions of Brazil (1999-2000

    Directory of Open Access Journals (Sweden)

    F. Rossi

    Full Text Available Resistance of microbes to commonly used antibiotics became a major concern at the end of the last century. Because Streptococcus pneumoniae is the most common pathogen in respiratory infections, we conducted microbiological assessment of drug susceptibility patterns among strains collected from two different population groups: 1 adult and pediatric patients (375 isolates with different infections, and 2 healthy children in day care centers (< 5 years old; 350 isolates. High level resistance to penicillin was not identified in either group. Intermediate resistance levels were similar in both groups (adults: 9.9%; children: 9.2%. The Central West region of Brazil tended to have lower susceptibility of S.pneumoniae from infected adults and children to penicillin (81% vs. 93% in the South and 90% in the Southeast, tetracycline (64% vs. 80% and 76%, and trimethoprim/sulfamethoxazole (14% vs. 34%. Susceptibility was similar among strains from nasal cultures of healthy children tested in each of 4 regions of Brazil. All isolates were susceptible to cefaclor, cefotaxime and amoxacillin/clavulanate. This study, in two distinct populations, allowed characterization of local microbiological resistance patterns. This data is expected to be of use in guiding empiric therapy in the different regions of Brazil.

  15. Vaccine-induced cellular immune responses differ from innate responses in susceptible and resistant strains of mice infected with Coccidioides posadasii.

    Science.gov (United States)

    Shubitz, Lisa F; Dial, Sharon M; Perrill, Robert; Casement, Rachael; Galgiani, John N

    2008-12-01

    Susceptibility to Coccidioides spp. varies widely in humans and other mammals and also among individuals within a species. Among strains of mice with various susceptibilities, immunohistopathology revealed that C57BL/6 mice were highly susceptible to the disease following intranasal infection, DBA/2n mice were intermediate, and Swiss-Webster mice were innately resistant. Resistant Swiss-Webster mice developed prominent perivascular/peribronchiolar lymphocytic cuffing and well-formed granulomas with few fungal elements and debris in the necrotic center, surrounded by a mantle of macrophages, lymphocytes, and fibrocytes. Susceptible C57BL/6 mice became moribund between 14 and 18 days postinfection, with overwhelming numbers of neutrophils and spherules and very few T cells, the drastic reduction of which was associated with failure and death, while intermediate DBA/2n mice controlled the fungal burden but demonstrated progressive lung inflammation with prominent suppuration, and they deteriorated clinically. Vaccinated C57BL/6 mice had an early and robust lymphocyte response, which included significantly higher Mac2(+), CD3(+), and CD4(+) cell scores on day 18 than those of innately resistant SW mice and DBA/2n mice; they also had prominent perivascular/peribronchiolar lymphocytic infiltrates not present in their unvaccinated counterparts, and they appeared to be resolving lesions by day 56 compared to the other two strains, based on significantly lower disease scores and observably smaller and fewer lesions with few spherules and neutrophils.

  16. Differential TLR7-mediated expression of proinflammatory and antiviral cytokines in response to laboratory and clinical enterovirus strains.

    Science.gov (United States)

    Chehadeh, Wassim; Alkhabbaz, Marwa

    2013-06-01

    Enteroviruses (EVs) are single stranded RNA viruses associated with many serious diseases. The exact mechanism by which an EV is able to evade innate immunity and cause tissue damage still remain unknown. Toll-like receptor 7 (TLR7) mediates the activation of type I interferon genes and the development of inflammatory cytokine response. The main aim of the study was to explore the antiviral activity and the pattern of cytokine expression in human embryonic kidney cells (HEK-293 cells) expressing TLR7 protein following challenging with laboratory and clinical EV strains. The TLR7 open reading frame was cloned into the pcDNA3.1/nV5-DEST™ expression vector, followed by transfection into HEK-293 cells. TLR7- and mock-transfected cells were infected with laboratory and clinical strains of CVB1 and CVB5. The levels of cytokines (IL-6, IL-8, TNF-α, IFN-α and IFN-β) were measured by ELISA. The EV RNA concentrations were measured by real-time RT-PCR, and normalized against GAPDH RNA concentrations. The clinical EV strains were more effective activators of cytokines production in TLR7-transfected cells than the laboratory EV strains. The inhibition of EV replication in TLR7-transfected cells was correlated to the production of type I IFNs. The cytopathic effects observed in TLR7-transfected cells were correlated to the levels of IL-6 and TNF-α. The results suggest a clear segregation between laboratory and clinical EV strains on the basis of their cytokine induction ability, and a possible role of TLR7-induced proinflammatory cytokines in the pathogenesis of EV infection. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Role of acidic pH in the susceptibility of intraphagocytic methicillin-resistant Staphylococcus aureus strains to meropenem and cloxacillin.

    Science.gov (United States)

    Lemaire, Sandrine; Van Bambeke, Françoise; Mingeot-Leclercq, Marie-Paule; Glupczynski, Youri; Tulkens, Paul M

    2007-05-01

    Early studies showed that methicillin-resistant Staphylococcus aureus (MRSA) strains are susceptible to beta-lactams when they are exposed to pH cloxacillin (CLX). Using a pharmacodynamic model assessing key pharmacological (50% effective concentration and maximal efficacy) and microbiological (static concentration) descriptors of antibiotic activity, we show that intraphagocytic MRSA strains are as sensitive to MEM and CLX as methicillin-susceptible S. aureus (MSSA; ATCC 25923). This observation was replicated in broth if the pH was brought to 5.5 and was confirmed with clinical strains. Electron microscopy showed that both the MRSA and the MSSA strains localized and multiplied in membrane-bounded structures (phagolysosomes) in the absence of beta-lactams. Incubation of the infected macrophages with ammonium chloride (to raise the phagolysosomal pH) made MRSA insensitive to MEM and CLX. No difference was seen in mec, mecA, mecI, mecR1, femA, and femB expression (reversed transcription-PCR) or in PBP 2a content (immunodetection) in MRSA grown in broth at pH 5.5 compared with that in MRSA grown in broth at 7.4. The level of [(14)C]benzylpenicillin binding to cell walls prepared from a non-beta-lactamase-producing MRSA clinical isolate was two times lower than that to cell walls prepared from MSSA ATCC 25923 at pH 7.4, but the levels increased to similar values for both strains at pH 5.5. These data suggest that the restoration of susceptibility of intraphagocytic of MRSA to MEM and CLX is due to the acidic pH prevailing in phagolysosomes and is mediated by an enhanced binding to penicillin-binding proteins.

  18. Mating of 2 Laboratory Saccharomyces cerevisiae Strains Resulted in Enhanced Production of 2-Phenylethanol by Biotransformation of L-Phenylalanine.

    Science.gov (United States)

    Mierzejewska, Jolanta; Tymoszewska, Aleksandra; Chreptowicz, Karolina; Krol, Kamil

    2017-01-01

    2-Phenylethanol (2-PE) is an aromatic alcohol with a rosy scent which is widely used in the food, fragrance, and cosmetic industries. Promising sources of natural 2-PE are microorganisms, especially yeasts, which can produce 2-PE by biosynthesis and biotransformation. Thus, the first challenging goal in the development of biotechnological production of 2-PE is searching for highly productive yeast strains. In the present work, 5 laboratory Saccharomyces cerevisiae strains were tested for the production of 2-PE. Thereafter, 2 of them were hybridized by a mating procedure and, as a result, a new diploid, S. cerevisiae AM1-d, was selected. Within the 72-h batch culture in a medium containing 5 g/L of L-phenylalanine, AM1-d produced 3.83 g/L of 2-PE in a shaking flask. In this way, we managed to select the diploid S. cerevisiae AM1-d strain, showing a 3- and 5-fold increase in 2-PE production in comparison to parental strains. Remarkably, the enhanced production of 2-PE by the hybrid of 2 yeast laboratory strains is demonstrated here for the first time. © 2017 S. Karger AG, Basel.

  19. Co-utilization of L-arabinose and D-xylose by laboratory and industrial Saccharomyces cerevisiae strains

    Directory of Open Access Journals (Sweden)

    Boles Eckhard

    2006-04-01

    Full Text Available Abstract Background Fermentation of lignocellulosic biomass is an attractive alternative for the production of bioethanol. Traditionally, the yeast Saccharomyces cerevisiae is used in industrial ethanol fermentations. However, S. cerevisiae is naturally not able to ferment the pentose sugars D-xylose and L-arabinose, which are present in high amounts in lignocellulosic raw materials. Results We describe the engineering of laboratory and industrial S. cerevisiae strains to co-ferment the pentose sugars D-xylose and L-arabinose. Introduction of a fungal xylose and a bacterial arabinose pathway resulted in strains able to grow on both pentose sugars. Introduction of a xylose pathway into an arabinose-fermenting laboratory strain resulted in nearly complete conversion of arabinose into arabitol due to the L-arabinose reductase activity of the xylose reductase. The industrial strain displayed lower arabitol yield and increased ethanol yield from xylose and arabinose. Conclusion Our work demonstrates simultaneous co-utilization of xylose and arabinose in recombinant strains of S. cerevisiae. In addition, the co-utilization of arabinose together with xylose significantly reduced formation of the by-product xylitol, which contributed to improved ethanol production.

  20. Genome-wide sequencing and an open reading frame analysis of dichlorodiphenyltrichloroethane (DDT susceptible (91-C and resistant (91-R Drosophila melanogaster laboratory populations.

    Directory of Open Access Journals (Sweden)

    Laura D Steele

    Full Text Available The Drosophila melanogaster 91-R and 91-C strains are of common origin, however, 91-R has been intensely selected for dichlorodiphenyltrichloroethane (DDT resistance over six decades while 91-C has been maintained as the non-selected control strain. These fly strains represent a unique genetic resource to understand the accumulation and fixation of mutations under laboratory conditions over decades of pesticide selection. Considerable research has been done to investigate the differential expression of genes associated with the highly DDT resistant strain 91-R, however, with the advent of whole genome sequencing we can now begin to develop an in depth understanding of the genomic changes associated with this intense decades-long xenobiotic selection pressure. Here we present the first whole genome sequencing analysis of the 91-R and 91-C fly strains to identify genome-wide structural changes within the open reading frames. Between-strain changes in allele frequencies revealed a higher percent of new alleles going to fixation for the 91-R strain, as compared to 91-C (P<0.0001. These results suggest that resistance to DDT in the 91-R laboratory strain could potentially be due primarily to new mutations, as well as being polygenic rather than the result of a few major mutations, two hypotheses that remain to be tested.

  1. Genome-wide sequencing and an open reading frame analysis of dichlorodiphenyltrichloroethane (DDT) susceptible (91-C) and resistant (91-R) Drosophila melanogaster laboratory populations.

    Science.gov (United States)

    Steele, Laura D; Muir, William M; Seong, Keon Mook; Valero, M Carmen; Rangesa, Madhumitha; Sun, Weilin; Clark, John M; Coates, Brad; Pittendrigh, Barry R

    2014-01-01

    The Drosophila melanogaster 91-R and 91-C strains are of common origin, however, 91-R has been intensely selected for dichlorodiphenyltrichloroethane (DDT) resistance over six decades while 91-C has been maintained as the non-selected control strain. These fly strains represent a unique genetic resource to understand the accumulation and fixation of mutations under laboratory conditions over decades of pesticide selection. Considerable research has been done to investigate the differential expression of genes associated with the highly DDT resistant strain 91-R, however, with the advent of whole genome sequencing we can now begin to develop an in depth understanding of the genomic changes associated with this intense decades-long xenobiotic selection pressure. Here we present the first whole genome sequencing analysis of the 91-R and 91-C fly strains to identify genome-wide structural changes within the open reading frames. Between-strain changes in allele frequencies revealed a higher percent of new alleles going to fixation for the 91-R strain, as compared to 91-C (PDDT in the 91-R laboratory strain could potentially be due primarily to new mutations, as well as being polygenic rather than the result of a few major mutations, two hypotheses that remain to be tested.

  2. Life beyond the laboratory: Selection, cultivation and molecular identification of new robust algal strains for use in extreme environments

    Science.gov (United States)

    Kloeck, Gerd; Franziska Bleeke, M. Sc.; Corinna Kontradowitz, M. Sc.; Noke, Anja

    Microalgae are some of the world's oldest organisms, phylogenetically. Microalgae can be found virtually everywhere, adapted to almost any habitat, from oceans and fresh-water lakes to deserts, arctic regions and the interior of rocks.Because microalgae can, in principle, adapt to a wide range of environmental conditions, these organisms are of special interest in life support and space exploration. However, most current studies on microalgae are perfomend with labo-ratory strains or so calles "model organisms", which are usually do not grow well under extreme conditions. We report here the results of a screening programme for new algae strains, which grow fast at elevated temperatures, extreme pH values, high irradiance and variing osmolari-ties. About 130 samples from sites in Germany, Spain (Mainland, Balearic and Canary Islands), Italy, Portugal and New Zealand were collected. The algae were isolated and maintained in liq-uid media. From a total of 30 pure cultures growth curves were created and doubling times and growth rates were determined. most strains grew very fast, the isolate T306A hat a generation time of =0.05h-1 and a doubling time of td= 14.3h-1. Temperature sensitivity tests revealed that most algae (also most laboratory strains) did not tolerate temperatures above 40C. We identifiesd about 30 strains whose thermo tolerance was above 40C. Isolate R7 grew even at 47C. Within the framework of the molecular identification by means of 18S rDNA sequencing, 22 iso-lates could be determined phylogenetically. Chlorophytes deriving from four different families (Scenedesmaceae, Chlorellaceae, Chlorococcaceae and Chlamydomonadaceae) were identified. Beside the already molecular identified strains, more than 20 strains are available for further experiments.

  3. Relationship between the Antifungal Susceptibility Profile and the Production of Virulence-Related Hydrolytic Enzymes in Brazilian Clinical Strains of Candida glabrata

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    Maria Helena Galdino Figueiredo-Carvalho

    2017-01-01

    Full Text Available Candida glabrata is a facultative intracellular opportunistic fungal pathogen in human infections. Several virulence-associated attributes are involved in its pathogenesis, host-pathogen interactions, modulation of host immune defenses, and regulation of antifungal drug resistance. This study evaluated the in vitro antifungal susceptibility profile to five antifungal agents, the production of seven hydrolytic enzymes related to virulence, and the relationship between these phenotypes in 91 clinical strains of C. glabrata. All C. glabrata strains were susceptible to flucytosine. However, some of these strains showed resistance to amphotericin B (9.9%, fluconazole (15.4%, itraconazole (5.5%, or micafungin (15.4%. Overall, C. glabrata strains were good producers of catalase, aspartic protease, esterase, phytase, and hemolysin. However, caseinase and phospholipase in vitro activities were not detected. Statistically significant correlations were identified between micafungin minimum inhibitory concentration (MIC and esterase production, between fluconazole and micafungin MIC and hemolytic activity, and between amphotericin B MIC and phytase production. These results contribute to clarify some of the C. glabrata mechanisms of pathogenicity. Moreover, the association between some virulence attributes and the regulation of antifungal resistance encourage the development of new therapeutic strategies involving virulence mechanisms as potential targets for effective antifungal drug development for the treatment of C. glabrata infections.

  4. Comparison of species-level identification and antifungal susceptibility results from diagnostic and reference laboratories for bloodstream Candida surveillance isolates, South Africa, 2009-2010.

    Science.gov (United States)

    Naicker, Serisha D; Govender, Nevashan; Patel, Jaymati; Zietsman, Inge L; Wadula, Jeannette; Coovadia, Yacoob; Kularatne, Ranmini; Seetharam, Sharona; Govender, Nelesh P

    2016-11-01

    From February 2009 through August 2010, we compared species-level identification of bloodstream Candida isolates and susceptibility to fluconazole, voriconazole, and caspofungin between diagnostic and reference South African laboratories during national surveillance for candidemia. Diagnostic laboratories identified isolates to genus/species level and performed antifungal susceptibility testing, as indicated. At a reference laboratory, viable Candida isolates were identified to species-level using automated systems, biochemical tests, or DNA sequencing; broth dilution susceptibility testing was performed. Categorical agreement (CA) was calculated for susceptibility results of isolates with concordant species identification. Overall, 2172 incident cases were detected, 773 (36%) by surveillance audit. The Vitek 2 YST system (bioMérieux Inc, Marcy l'Etoile, France) was used for identification (360/863, 42%) and susceptibility testing (198/473, 42%) of a large proportion of isolates. For the five most common species (n = 1181), species-level identification was identical in the majority of cases (Candida albicans: 98% (507/517); Candida parapsilosis: 92% (450/488); Candida glabrata: 89% (89/100); Candida tropicalis: 91% (49/54), and Candida krusei: 86% (19/22)). However, diagnostic laboratories were significantly less likely to correctly identify Candida species other than C. albicans versus C. albicans (607/664, 91% vs. 507/517, 98%; P albicans (36/362, 10% vs. 3/362, 0.8%; P Candida species other than C. albicans, under-reported fluconazole resistance for C. parapsilosis and over-reported fluconazole resistance for C. albicans. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Knowledge and practices of laboratory workers on standardized antimicrobial susceptibility testing and biosafety practices to prevent the spread of superbugs in Pakistan.

    Science.gov (United States)

    Ghanchi, Najia K; Khan, Erum; Farooqi, Joveria Q; Fasih, Naima; Dojki, Maqboola; Hughes, Molly A

    2014-09-01

    A cross-sectional survey using structured questionnaire was conducted to assess practices of microbiological laboratories working with pathogens. Forty-eight laboratory workers (50%) agreed that laboratory methods to detect antimicrobial resistance are not standardized in Pakistan, and 6% of the laboratory workers were not aware of the standardization of antimicrobial susceptibility testing in Pakistan. Reported rates of awareness regarding the role of waste disposal, disinfection, and handwashing in limiting the spread of antimicrobial resistance were 75%, 42%, and 81%, respectively. Our results provide baseline data for planning programs to train, supervise, and improve the operational quality of microbiological laboratories nationwide to prevent the spread of superbugs. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  6. Co-utilization of L-arabinose and D-xylose by laboratory and industrial Saccharomyces cerevisiae strains

    OpenAIRE

    Boles Eckhard; Hahn-Hägerdal Bärbel; Wiedemann Beate; Karhumaa Kaisa; Gorwa-Grauslund Marie-F

    2006-01-01

    Abstract Background Fermentation of lignocellulosic biomass is an attractive alternative for the production of bioethanol. Traditionally, the yeast Saccharomyces cerevisiae is used in industrial ethanol fermentations. However, S. cerevisiae is naturally not able to ferment the pentose sugars D-xylose and L-arabinose, which are present in high amounts in lignocellulosic raw materials. Results We describe the engineering of laboratory and industrial S. cerevisiae strains to co-ferment the pento...

  7. Microbial Enhanced Oil Recovery-Laboratory Experiments with a Strain of Clostridium tyrobutyricum

    DEFF Research Database (Denmark)

    Jimoh, Ismaila Adetunji

    the desired metabolic products needed for enhanced oil recovery. In this study, experiments have been performed with a strain of Clostridium tyrobutyricum. The experiments focused on salinity adaptation, gas production and the ability of microbes to modify rock properties. The result of the experiments showed...... that the strain of Clostridium tyrobutyricum adapted to 10, 30, 50, and 90 g/l before the start of the experiments produce more gas with an increase factor of between 0.39-6.9 for the same salinity condition than the pure culture. The adaptation process also led to the production of a strain 90F which can grow...... and produce metabolites at salinity range of over 90g/l. Strain 90F which is the adapted strain, frozen over a long period of time when activated were also able to attach to the oil water interface when grown inside test tubes at high salinity range. This can change the interfacial or wetting properties...

  8. Evaluation of efficacy of 18 strains of entomopathogenic nematodes (Rhabditida) against Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) under laboratory conditions.

    Science.gov (United States)

    Barbosa Negrisoli, Carla Ruth de Carvalho; Negrisoli Júnior, Aldomario Santo; Botton, Marcos; Garcia, Mauro Silveira; Bernardi, Daniel

    2013-07-01

    Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) is an important plant virus vector in grapevine crops in Brazil and other countries. The mealybug grows in roots and leaves of the grapes. Entomopathogenic nematodes (EPNs) are efficient control agents against insects associated to the soil and could be applied with the same equipment used for chemical insecticides. The aim of this study was to select effective EPNs for controlling P. citri females in laboratory conditions (25±1°C, UR 60±10%). We tested 17 native [Steinernema rarum (6 strains), Steinernema glaseri, Steinernema feltiae, Steinernema riobrave, Steinernema sp., Heterorhabditis bacteriophora (7 strains)] and only one exotic strain (Steinernema carpocapsae ALL). The bioassays were done on Petri dishes infested with females of P. citri, which were sprayed with EPNs juveniles. The strain with larger pathogenicity and virulence in laboratory was H. bacteriophora RS33 (from 69.0% to 92.2% of mortality), native of Rio Grande do Sul. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Antimicrobial Susceptibility of Bacillus Strains Isolated from Primary Starters for African Traditional Bread Production and Characterization of the Bacitracin Operon and Bacitracin Biosynthesis

    Science.gov (United States)

    Sørensen, Kim I.; Thorsen, Line; Stuer-Lauridsen, Birgitte; Abdelgadir, Warda S.; Nielsen, Dennis S.; Derkx, Patrick M. F.; Jespersen, Lene

    2012-01-01

    Bacillus spp. are widely used as feed additives and probiotics. However, there is limited information on their resistance to various antibiotics, and there is a growing concern over the transfer of antibiotic resistance genes. The MIC for 8 antibiotics was determined for 85 Bacillus species strains, Bacillus subtilis subsp. subtilis (n = 29), Bacillus licheniformis (n = 38), and Bacillus sonorensis (n = 18), all of which were isolated from starters for Sudanese bread production. All the strains were sensitive to tetracycline (8.0 mg/liter), vancomycin (4.0 mg/liter), and gentamicin (4.0 mg/liter) but resistant to streptomycin. Sensitivity to clindamycin, chloramphenicol, and kanamycin was species specific. The erythromycin resistance genes ermD and ermK were detected by PCR in all of the erythromycin-resistant (MIC, ≥16.0 mg/liter) B. licheniformis strains and one erythromycin-sensitive (MIC, 4.0 mg/liter) B. licheniformis strain. Several amino acid changes were present in the translated ermD and ermK nucleotide sequences of the erythromycin-sensitive strain, which could indicate ErmD and ErmK protein functionalities different from those of the resistance strains. The ermD and ermK genes were localized on an 11.4-kbp plasmid. All of the B. sonorensis strains harbored the bacitracin synthetase gene, bacA, and the transporter gene bcrA, which correlated with their observed resistance to bacitracin. Bacitracin was produced by all the investigated species strains (28%), as determined by ultra-high-definition quadrupole time-of-flight liquid chromatography-mass spectrometry (UHD-QTOF LC/MS). The present study has revealed species-specific variations in the antimicrobial susceptibilities of Bacillus spp. and provides new information on MIC values, as well as the occurrence of resistance genes in Bacillus spp., including the newly described species B. sonorensis. PMID:22941078

  10. Role of Acidic pH in the Susceptibility of Intraphagocytic Methicillin-Resistant Staphylococcus aureus Strains to Meropenem and Cloxacillin▿

    Science.gov (United States)

    Lemaire, Sandrine; Van Bambeke, Françoise; Mingeot-Leclercq, Marie-Paule; Glupczynski, Youri; Tulkens, Paul M.

    2007-01-01

    Early studies showed that methicillin-resistant Staphylococcus aureus (MRSA) strains are susceptible to β-lactams when they are exposed to pH ≤ 5.5 in broth. Because S. aureus survives in the phagolysosomes of macrophages, where the pH may be acidic, we have examined the susceptibility of MRSA ATCC 33591 phagocytized by human THP-1 macrophages to meropenem (MEM) and cloxacillin (CLX). Using a pharmacodynamic model assessing key pharmacological (50% effective concentration and maximal efficacy) and microbiological (static concentration) descriptors of antibiotic activity, we show that intraphagocytic MRSA strains are as sensitive to MEM and CLX as methicillin-susceptible S. aureus (MSSA; ATCC 25923). This observation was replicated in broth if the pH was brought to 5.5 and was confirmed with clinical strains. Electron microscopy showed that both the MRSA and the MSSA strains localized and multiplied in membrane-bounded structures (phagolysosomes) in the absence of β-lactams. Incubation of the infected macrophages with ammonium chloride (to raise the phagolysosomal pH) made MRSA insensitive to MEM and CLX. No difference was seen in mec, mecA, mecI, mecR1, femA, and femB expression (reversed transcription-PCR) or in PBP 2a content (immunodetection) in MRSA grown in broth at pH 5.5 compared with that in MRSA grown in broth at 7.4. The level of [14C]benzylpenicillin binding to cell walls prepared from a non-β-lactamase-producing MRSA clinical isolate was two times lower than that to cell walls prepared from MSSA ATCC 25923 at pH 7.4, but the levels increased to similar values for both strains at pH 5.5. These data suggest that the restoration of susceptibility of intraphagocytic of MRSA to MEM and CLX is due to the acidic pH prevailing in phagolysosomes and is mediated by an enhanced binding to penicillin-binding proteins. PMID:17307986

  11. A comparison of Anisotropy of Magnetic Susceptibility Studies to Clast Based Strain Analysis in Sandstones, From The Outer Margin Of The Sevier Orogenic Foreland, Western Wyoming.

    Science.gov (United States)

    Mc Carthy, Dave; Meere, Pat; Petronis, Mike; Mulchrone, Kieran

    2013-04-01

    The Cordilleran Mountain Belt of North America is one of the world's classic foreland fold and thrust belts. The Sevier Belt represents the thin skinned front of this orogeny, consisting of thrust faults and folds that shortened and transported sequences of Devonian to Cretaceous strata eastward. There is a general increase in deformation westwards which provides an ideal geological setting to explore the potential link between Anisotropy of Magnetic Susceptibility (AMS) and results from clast based strain analyses of sandstones. Studies attempting to define the relationship between AMS and finite strain have been in vogue since the link between layer parallel shortening and AMS was first established. The understanding of this relationship, despite proven strong correlations between the AMS tensors and tectonic directions, is complicated by competing sub-fabrics, as well as the various magnetic properties of the minerals contributing to the AMS fabric. It has become very clear that the sensitivity of AMS is capable of detecting incipient tectonic fabrics, <5% shortening, which is typically outside the range of most dedicated strain analyses. Despite this, there has been little published research into the relationship between the classic fabric analysis techniques or strain estimate methods and AMS. This may be due to the particularly laborious task of calculating strain estimates using large marker populations and/or the pitfalls of trying to relate the magnitudes of the magnetic ellipse to the magnitudes of the strain ellipse. Rather than trying to estimate finite strain directly from the AMS ellipsoid, we are using the ability of AMS to accurately and quickly qualify the petrofabric and determine the origin of that fabric (i.e., whether it is purely sedimentary, composite bedding/tectonic or dominantly tectonic etc.). Where as most methods of estimating strain have poor accuracy constraints in low strain regimes. In an attempt to account for this AMS is being

  12. Antimicrobial susceptibility of Escherichia coli F4, Pasteurella multocida, and Streptococcus suis isolates from a diagnostic veterinary laboratory and recommendations for a surveillance system.

    Science.gov (United States)

    Glass-Kaastra, Shiona K; Pearl, David L; Reid-Smith, Richard J; McEwen, Beverly; Slavic, Durda; McEwen, Scott A; Fairles, Jim

    2014-04-01

    Antimicrobial susceptibility data on Escherichia coli F4, Pasteurella multocida, and Streptococcus suis isolates from Ontario swine (January 1998 to October 2010) were acquired from a comprehensive diagnostic veterinary laboratory in Ontario, Canada. In relation to the possible development of a surveillance system for antimicrobial resistance, data were assessed for ease of management, completeness, consistency, and applicability for temporal and spatial statistical analyses. Limited farm location data precluded spatial analyses and missing demographic data limited their use as predictors within multivariable statistical models. Changes in the standard panel of antimicrobials used for susceptibility testing reduced the number of antimicrobials available for temporal analyses. Data consistency and quality could improve over time in this and similar diagnostic laboratory settings by encouraging complete reporting with sample submission and by modifying database systems to limit free-text data entry. These changes could make more statistical methods available for disease surveillance and cluster detection.

  13. Epidemiology and antimicrobial susceptibilities of 111 Campylobacter fetus subsp. fetus strains isolated in Québec, Canada, from 1983 to 2000.

    Science.gov (United States)

    Tremblay, Carole; Gaudreau, Christiane; Lorange, Manon

    2003-01-01

    The epidemiology and antimicrobial susceptibilities of 111 Campylobacter fetus subsp. fetus strains isolated from 103 patients from 1983 to 2000 in Québec, Canada, were determined. The median number of patients infected annually with this bacteria was seven, with an incidence of 0.1 per 100,000 population. The male-to-female ratio was 1.1 to 1.0. The patients originated from 13 of the 18 Québec socioeconomic regions. The age range of the patients was 6 months to 90 years old, 53% being > or = 70 years old and 2% being <20 years old. The isolation site was blood for 69% of the patients, stools for 20%, and other body fluids for 11% of them. Three patients suffered a relapse, with the same strain being isolated from the same site at different times as confirmed by pulse-field gel electrophoresis. All isolates were susceptible to ampicillin, gentamicin, meropenem, and imipenem, with 90% minimal inhibitory concentrations of 4, 1, 0.12, and < or = 0.06 microg/ml, respectively. Three percent and two percent of the strains were, respectively, resistant and intermediate to ciprofloxacin. Thirty-four percent of the strains were resistant to tetracycline. There was a nonsignificant increase in resistance to ciprofloxacin (P = 0.27) and to tetracycline (P = 0.65) in recent years. The percentages of intermediate and resistant MICs were, respectively, 12 and 1% for cefotaxime and 71 and 0% for erythromycin. All strains were beta-lactamase negative.

  14. Genetic variations of live attenuated plague vaccine strains (Yersinia pestis EV76 lineage) during laboratory passages in different countries.

    Science.gov (United States)

    Cui, Yujun; Yang, Xianwei; Xiao, Xiao; Anisimov, Andrey P; Li, Dongfang; Yan, Yanfeng; Zhou, Dongsheng; Rajerison, Minoarisoa; Carniel, Elisabeth; Achtman, Mark; Yang, Ruifu; Song, Yajun

    2014-08-01

    Plague, one of the most devastating infectious diseases in human history, is caused by the bacterial species Yersinia pestis. A live attenuated Y. pestis strain (EV76) has been widely used as a plague vaccine in various countries around the world. Here we compared the whole genome sequence of an EV76 strain used in China (EV76-CN) with the genomes of Y. pestis wild isolates to identify genetic variations specific to the EV76 lineage. We identified 6 SNPs and 6 Indels (insertions and deletions) differentiating EV76-CN from its counterparts. Then, we screened these polymorphic sites in 28 other strains of EV76 lineage that were stored in different countries. Based on the profiles of SNPs and Indels, we reconstructed the parsimonious dissemination history of EV76 lineage. This analysis revealed that there have been at least three independent imports of EV76 strains into China. Additionally, we observed that the pyrE gene is a mutation hotspot in EV76 lineages. The fine comparison results based on whole genome sequence in this study provide better understanding of the effects of laboratory passages on the accumulation of genetic polymorphisms in plague vaccine strains. These variations identified here will also be helpful in discriminating different EV76 derivatives. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. A Laboratory Study to Determine the Effect of Field Strength and Magnetic Susceptibility on the NMR Estimated Water Content in Unconsolidated Sediments

    Science.gov (United States)

    Keating, K.; Grunewald, E. D.; Walsh, D. O.

    2015-12-01

    Geophysical nuclear magnetic resonance (NMR) well logging data can provide direct information about subsurface water content. While NMR water content estimates are known to be accurate in low magnetic susceptibility materials, it has often been assumed that NMR measurements cannot be used in high magnetic susceptibility materials due to internal magnetic field inhomogeneities that arise due to magnetic susceptibility contrasts in the material. In this study we compare the NMR estimated water content using laboratory measurements made at two low magnetic field strengths (with Larmor frequencies of 275 kHz and 2 MHz) on both synthetic and natural unconsolidated sediments with a range of magnetic susceptibility values. NMR measurements were collected on seven water-saturated materials with magnetic susceptibility values spanning three orders of magnitude (3.6x10-6 SI to 7.0 x10-3 SI). T2 relaxation time data was collected with echo times, tE, ranging from 200 to 3000 μs. The results show that for the materials with low magnetic susceptibilities (magnetic susceptibilities (> 5x10-4 SI) the water content was more accurately estimated using the data collected at 275 kHz (> 80% detected at tE = 400 μs) than the data collected at 2 MHz (< 40% detected at tE = 400 μs). Furthermore, the 275 kHz data showed water content underestimation errors increased only slightly with increased tE, compared to substantial increases in errors for the 2 MHz data as tE was increased. This finding suggests that there is an advantage for collecting measurements at lower field strengths even for long tE. We explain the differences in the water content estimates at the two field strengths by considering the shape of the echoes and the coil and pulse bandwidths, and find excellent agreement with the range of collected NMR data.

  16. Variations in biofilm formation, desiccation resistance and Benzalkonium chloride susceptibility among Listeria monocytogenes strains isolated in Canada

    DEFF Research Database (Denmark)

    Piercey, Marta J.; C. Ells, Timothy; Macintosh, Andrew J.

    2017-01-01

    needed to inhibit the formation of biofilm by LGI1/CC8 strains during incubation for 48 h and 6 days compared to other strains. Formation of biofilm on stainless steel was not significantly (p > 0.05) different among the strains. Analysis of genetic sequence data from desiccation and BAC sensitive (CP4 5......Listeria monocytogenes is a pathogenic foodborne microorganism noted for its ability to survive in the environment and food processing facilities. Survival may be related to the phenotype of individual strains including the ability to form biofilms and resist desiccation and/or sanitizer exposure....... The objectives of this research were to compare 14 L. monocytogenes strains isolated from blood (3), food (6) and water (5) with respect to their benzalkonium chloride (BAC) sensitivity, desiccation resistance, and ability to form biofilm. Correlations were tested between those responses, and the presence...

  17. Changes in antimicrobial susceptibility profile and prevalence of quinolone low-sensitive strains in subgingival plaque from acute periodontal lesions after systemic administration of sitafloxacin.

    Science.gov (United States)

    Tomita, Sachiyo; Kasai, Shunsuke; Imamura, Kentaro; Ihara, Yuichiro; Kita, Daichi; Ota, Koki; Sekino, Jin; Nakagawa, Taneaki; Saito, Atsushi

    2015-02-01

    This study aimed to assess changes in antimicrobial susceptibilities of subgingival bacteria in acute periodontal lesions following systemic administration of a new-generation fluoroquinolone, sitafloxacin and to monitor the occurrence and fate of quinolone low-sensitive strains. Patients with acute phase of chronic periodontitis were subjected to microbiological assessment of their subgingival plaque samples at baseline (A1). Sitafloxacin was then administered systemically (100 mg/day for 5 days). The microbiological examinations were repeated one week after administration (A2). Susceptibilities of clinical isolates from acute sites to various antimicrobials were determined using broth and agar dilution methods. At A2, subgingival bacteria with low sensitivity to levofloxacin were identified in four patients, and they were subjected to a follow-up microbiological examination at on the average 12 months after sitafloxacin administration (A3). The patients received initial and supportive periodontal therapy during the period A2 to A3. From the examined subgingival sites, 8 and 19 clinical isolates were obtained at A2 and A3, respectively. Some Streptococcus strains isolated at A2 were found to be resistant to levofloxacin (MIC 16-64 μg/ml), azithromycin (MIC 2->128 μg/ml) or clarithromycin (MIC 1->32 μg/ml). At A3, isolated streptococci were highly susceptible to levofloxacin (MIC 0.5-2 μg/ml), while those resistant to azithromycin or clarithromycin were still isolated. It is suggested that the presence of the quinolone low-sensitive strains in initially acute lesions after sitafloxacin administration was transient, and they do not persist in the subgingival milieu during the periodontal therapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Disinfectant and antibiotic susceptibility profiles of Escherichia coli O157:H7 strains from cattle carcasses, feces, and hides and ground beef from the United States.

    Science.gov (United States)

    Beier, Ross C; Poole, Toni L; Brichta-Harhay, Dayna M; Anderson, Robin C; Bischoff, Kenneth M; Hernandez, Charles A; Bono, James L; Arthur, Terrance M; Nagaraja, T G; Crippen, Tawni L; Sheffield, Cynthia L; Nisbet, David J

    2013-01-01

    The disinfectant and antibiotic susceptibility profiles of 344 Escherichia coli O157:H7 strains from cattle carcasses, feces, and hides and ground beef from the United States were determined. A low prevalence of antibiotic resistance was observed (14%). The highest prevalences of resistance were to sulfisoxazole (10.5%), tetracycline (9.9%), streptomycin (7%), and chloramphenicol (4.9%). Four strains were resistant to eight antibiotics (two strains from ground beef and one strain each from hide and preevisceration carcass swabs of cull cattle at harvest). Pulsed-field gel electrophoresis analysis of the E. coli O157:H7 strains revealed two major groups (designated 1 and 2) composed of 17 and 20 clusters, respectively. Clusters 1A, 1B, 1C, and 1G.1 were associated with multidrug-resistant strains. There was no observed correlation between disinfectant resistance and antibiotic resistance. Sixty-nine (20%) of the 344 strains were resistant to chlorhexidine or benzalkonium chloride or the MICs of benzyldimethyldodecylammonium chloride were elevated. Inducible resistance was observed at elevated concentrations of antibiotics (1.4%) and disinfectants (6.1%). The highest rate of disinfectant inducible resistance was to OdoBan, quaternary ammonium chlorides, and the surface disinfectants F25, FS512, and MG, which are used in dairies, restaurants, and food processing plants. High MICs (1,024 to 4,096 m g/ml) of acetic, lactic, and citric acids were found. The decreasing order of acid potency based on molar MICs (MICs(molar)) was acetic, citric, and lactic acid. The correlation of the concentration of dissociated organic acids and MICs(molar) strongly suggests that the observed inhibition of E. coli O157:H7 was primarily due to dissociated forms of the acids.

  19. Antibacterial effects of Apis mellifera and stingless bees honeys on susceptible and resistant strains of Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae in Gondar, Northwest Ethiopia.

    Science.gov (United States)

    Ewnetu, Yalemwork; Lemma, Wossenseged; Birhane, Nega

    2013-10-19

    Honey is a natural substance produced by honeybees and has nutritional and therapeutic uses. In Ethiopia, honeys are used traditionally to treat wounds, respiratory infections and diarrhoea. Recent increase of drug resistant bacteria against the existing antibiotics forced investigators to search for alternative natural remedies and evaluate their potential use on scientific bases. Thus, the aim of this study was to evaluate the antibacterial effects of different types of honeys in Ethiopia which are used traditionally to treat different types of respiratory and gastrointestinal infections. Mueller Hinton agar (70191) diffusion and nutrient broth culture medium assays were performed to determine susceptibility of Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922) and resistant clinical isolates (Methicillin resistant Staphylococcus aureus(MRSA), Escherichia coli(R) and Klebsiella pneumoniae (R), using honeys of Apis mellifera and stingless bees in northern and north western Ethiopia. Honey of the stingless bees produced the highest mean inhibition (22.27 ± 3.79 mm) compared to white honey (21.0 ± 2.7 mm) and yellow honey (18.0 ± 2.3 mm) at 50% (v/v) concentration on all the standard and resistant strains. Stingless bees honey was found to have Minimum Inhibitory Concentration (MIC) of 6.25% (6.25 mg/ml) for 80% of the test organisms compared to 40% for white and yellow Apis mellifera honeys. All the honeys were found to have minimum bactericidal concentration (MBC) of 12.5% (12.5 mg/ml) against all the test organisms. Staphylococcus aureus (ATCC 25923) was susceptible to amoxicillin, methicillin, kanamycine, tetracycline, and vancomycine standard antibiotic discs used for susceptibility tests. Similarly, Escherichia coli (ATCC 25922) was found susceptible for kanamycine, tetracycline and vancomycine. Escherichia coli (ATCC 25922) has not been tested for amoxicillin ampicillin and methicillin. The susceptibility tests performed against

  20. Insecticidal and sterilizing effect of Olyset Duo®, a permethrin and pyriproxyfen mixture net against pyrethroid-susceptible and -resistant strains of Anopheles gambiae s.s.: a release-recapture assay in experimental huts.

    Science.gov (United States)

    Djènontin, Armel; Ahoua Alou, Ludovic P; Koffi, Alphonsine; Zogo, Barnabas; Duarte, Elves; N'Guessan, Raphael; Moiroux, Nicolas; Pennetier, Cédric

    2015-01-01

    In the context of the widespread distribution of pyrethroid resistance among malaria vectors, we did a release-recapture trial in experimental huts to investigate the insecticidal and sterilizing effects of a novel long-lasting net (LN), Olyset® Duo, incorporating a mixture of permethrin (PER) and the insect growth regulator (IGR), pyri-proxyfen (PPF). An LN containing PPF alone and a classic Olyset® Net were tested in parallel as positive controls. The effect of progressive number of holes (6, 30, or 150) that may accrue in nets over time was simulated. We used two laboratory Anopheles gambiae s.s. strains: the susceptible Kisumu strain and the pyrethroid-resistant VK-Per strain having solely kdr as resistance mechanism. The effect of these nets on the reproductive success of blood-fed females that survived the different LNs conditions was recorded. Regardless of the mosquito strain, the LNs containing PPF alone with as many as 30 holes drastically reduced the number of eggs laid by females succeeding in feeding, i.e. fecundity by 98% and egg hatching rate (fertility) by 93% relative to untreated control net. Very few of the resistant females blood fed and survived under the Olyset® Duo with similar number of holes (up to 30) but of these few, the inhibition of reproductive success was 100%. There was no evidence that the Olyset® Duo LN with 150 holes impacted fecundity or fertility of the resistant colony. The efficacy of Olyset® Duo is encouraging and clearly illustrates that this new net might be a promising tool for malaria transmission control and resistance management. © A. Djènontin et al., published by EDP Sciences, 2015.

  1. Insecticidal and sterilizing effect of Olyset Duo®, a permethrin and pyriproxyfen mixture net against pyrethroid-susceptible and -resistant strains of Anopheles gambiae s.s.: a release-recapture assay in experimental huts

    Directory of Open Access Journals (Sweden)

    Djènontin Armel

    2015-01-01

    Full Text Available In the context of the widespread distribution of pyrethroid resistance among malaria vectors, we did a release-recapture trial in experimental huts to investigate the insecticidal and sterilizing effects of a novel long-lasting net (LN, Olyset® Duo, incorporating a mixture of permethrin (PER and the insect growth regulator (IGR, pyri-proxyfen (PPF. An LN containing PPF alone and a classic Olyset® Net were tested in parallel as positive controls. The effect of progressive number of holes (6, 30, or 150 that may accrue in nets over time was simulated. We used two laboratory Anopheles gambiae s.s. strains: the susceptible Kisumu strain and the pyrethroid-resistant VK-Per strain having solely kdr as resistance mechanism. The effect of these nets on the reproductive success of blood-fed females that survived the different LNs conditions was recorded. Regardless of the mosquito strain, the LNs containing PPF alone with as many as 30 holes drastically reduced the number of eggs laid by females succeeding in feeding, i.e. fecundity by 98% and egg hatching rate (fertility by 93% relative to untreated control net. Very few of the resistant females blood fed and survived under the Olyset® Duo with similar number of holes (up to 30 but of these few, the inhibition of reproductive success was 100%. There was no evidence that the Olyset® Duo LN with 150 holes impacted fecundity or fertility of the resistant colony. The efficacy of Olyset® Duo is encouraging and clearly illustrates that this new net might be a promising tool for malaria transmission control and resistance management.

  2. Insecticidal and sterilizing effect of Olyset Duo®, a permethrin and pyriproxyfen mixture net against pyrethroid-susceptible and -resistant strains of Anopheles gambiae s.s.: a release-recapture assay in experimental huts

    Science.gov (United States)

    Djènontin, Armel; Ahoua Alou, Ludovic P.; Koffi, Alphonsine; Zogo, Barnabas; Duarte, Elves; N’Guessan, Raphael; Moiroux, Nicolas; Pennetier, Cédric

    2015-01-01

    In the context of the widespread distribution of pyrethroid resistance among malaria vectors, we did a release-recapture trial in experimental huts to investigate the insecticidal and sterilizing effects of a novel long-lasting net (LN), Olyset® Duo, incorporating a mixture of permethrin (PER) and the insect growth regulator (IGR), pyri-proxyfen (PPF). An LN containing PPF alone and a classic Olyset® Net were tested in parallel as positive controls. The effect of progressive number of holes (6, 30, or 150) that may accrue in nets over time was simulated. We used two laboratory Anopheles gambiae s.s. strains: the susceptible Kisumu strain and the pyrethroid-resistant VK-Per strain having solely kdr as resistance mechanism. The effect of these nets on the reproductive success of blood-fed females that survived the different LNs conditions was recorded. Regardless of the mosquito strain, the LNs containing PPF alone with as many as 30 holes drastically reduced the number of eggs laid by females succeeding in feeding, i.e. fecundity by 98% and egg hatching rate (fertility) by 93% relative to untreated control net. Very few of the resistant females blood fed and survived under the Olyset® Duo with similar number of holes (up to 30) but of these few, the inhibition of reproductive success was 100%. There was no evidence that the Olyset® Duo LN with 150 holes impacted fecundity or fertility of the resistant colony. The efficacy of Olyset® Duo is encouraging and clearly illustrates that this new net might be a promising tool for malaria transmission control and resistance management. PMID:26489479

  3. GENOMIC IDENTIFICATION OF POTENTIAL RISK FACTORS DURING ACETAMINOPHEN-INDUCED LIVER DISEASE IN SUSCEPTIBLE AND RESISTANT STRAINS OF MICE

    Science.gov (United States)

    Drug-induced liver disease (DILD) continues to cause significant morbidity and mortality and impair new drug development. Mounting evidence suggests that DILD is a complex, multifactorial disease in which no one factor is likely to be an absolute indicator of susceptibility. As a...

  4. Growth Inhibitory, Bactericidal, and Morphostructural Effects of Dehydrocostus Lactone from Magnolia sieboldii Leaves on Antibiotic-Susceptible and -Resistant Strains of Helicobacter pylori

    Science.gov (United States)

    Lee, Hyun-Kyung; Song, Ha Eun; Lee, Haeng-Byung; Kim, Cheol-Soo; Koketsu, Mamoru; Thi My Ngan, Luong; Ahn, Young-Joon

    2014-01-01

    Helicobacter pylori is associated with various diseases of the upper gastrointestinal tract, such as gastric inflammation and duodenal and gastric ulcers. The aim of the study was to assess anti-H. pylori effects of the sesquiterpene lactone dehydrocostus lactone (DCL) from Magnolia sieboldii leaves, compared to commercial pure DCL, two previously known sesquiterpene lactones (costunolide and parthenolide), (–)-epigallocatechin gallate, and four antibiotics. The antibacterial activity of natural DCL toward antibiotic-susceptible H. pylori ATCC 700392 and H. pylori ATCC 700824 strains (MIC, 4.9 and 4.4 mg/L) was similar to that of commercial DCL and was more effective than costunolide, parthenolide, and EGCG. The activity of DCL was slightly lower than that of metronidazole (MIC, 1.10 and 1.07 mg/L). The antibacterial activity of DCL was virtually identical toward susceptible and resistant strains, even though resistance to amoxicillin (MIC, 11.1 mg/L for PED 503G strain), clarithromycin (49.8 mg/L for PED 3582GA strain), metronidazole (21.6 mg/L for H. pylori ATCC 43504 strain; 71.1 mg/L for 221 strain), or tetracycline (14.2 mg/L for B strain) was observed. This finding indicates that DCL and the antibiotics do not share a common mode of action. The bactericidal activity of DCL toward H. pylori ATCC 43504 was not affected by pH values examined (4.0–7.0). DCL caused considerable conversion to coccoid form (94 versus 49% at 8 and 4 mg/L of DCL for 48 h). The Western blot analysis revealed that urease subunits (UreA and UreB) of H. pylori ATCC 43504 were not affected by 10 mM of DCL, whereas UreA monomer band completely disappeared at 0.1 mM of (–)-epigallocatechin gallate. Global efforts to reduce the level of antibiotics justify further studies on M. sieboldii leaf-derived materials containing DCL as potential antibacterial products or a lead molecule for the prevention or eradication of drug-resistant H. pylori. PMID:24747984

  5. Antimicrobial susceptibility of Clostridium perfringens strains isolated from broiler chickens Sensibilidade antimicrobiana de estirpes de Clostridium perfringens isoladas de aves de corte

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    R. O. S. Silva

    2009-06-01

    Full Text Available Clostridium perfringens is a normal inhabitant of the intestinal tract of chickens as well as a potential pathogen that causes necrotic enteritis and colangio hepatitis. The minimum inhibitory concentration (MIC of seven different compounds used for therapy, growth promotion or prevention of coccidiosis was determined by agar dilution method for 55 C. perfringens strains isolated from the intestines of broiler chickens. All strains showed high susceptibility to penicillin, avilamycin, monensin and narasin. Only 7.3% of the strains showed an intermediated sensitivity to lincomycin, and 49 (89.1% were considered susceptible. For tetracycline and bacitracin, 41.8% and 47.3% of strains, respectively, were considered resistant.Clostridium perfringens é um habitante normal da microbiota intestinal de frangos, sendo um agente potencialmente patogênico, causador de enterite necrótica e colangio-hepatite. A concentração inibitória mínima (CIM de sete drogas utilizadas na terapêutica, como agentes promotores de crescimento ou na prevenção de coccidiose foi determinada pelo método de diluição em ágar para 55 estirpes de C. perfringens isoladas do intestino de frangos de corte. Todas as estirpes revelaram alta sensibilidade à penicilina, avilamicina, narasin e monensina, apenas 7,3% demonstraram CIM intermediário para lincomicina e 89.1% foram consideradas sensíveis. Para tetraciclina e bacitracina, 41,8% e 47.3% das amostras, respectivamente, foram consideradas resistentes.

  6. Antibiotic susceptibility of methicillin-resistant and methicillin-susceptible coagulase-negative staphylococci isolated from bovine mastitis.

    Science.gov (United States)

    Bochniarz, M; Wawron, W

    2011-01-01

    The aim of the present study was to evaluate the antibiotic susceptibility of methicillin-susceptible (MS) and methicillin-resistant (MR) coagulase-negative Staphylococcus (CNS) strains isolated from milk of cows with mastitis. The study was conducted on 100 CNS strains (20 MRCNS and 80 MSCNS) isolated from milk samples of 86 cows from the Lublin (Poland) region farms. Antibiotic susceptibility of microorganisms was evaluated using the disc-diffusion method on the Mueller-Hinton agar according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). The highest efficacy against MSCNS was demonstrated for cephalosporin antibiotics, i.e. cefacetril (91.3%), ceftiofur (67.5%), cefoperazone (66.3%) and cephalexin (60.0% of susceptible MSCNS strains). Moreover, a high percentage of vancomycin-susceptible strains was demonstrated (83.8%). The activity of combination of amoxicillin with clavulanic acid and gentamicin was found weaker (63.8% and 61.3% of susceptible strains, respectively). About 50.0% of MSCNS were susceptible to erythromycin, enrofloxacine and amoxicillin. A large proportion of CNS was resistant to neomycin, penicillin, tetracycline, streptomycin, lincomycin and ampicillin (28.8%, 30.0%, 31.3%, 31.3%, 33.8% and 33.8% of susceptible strains, respectively). The highest percentage of MRCNS was susceptible to vancomycin (75.0%), erythromycin (65.0%) and streptomycin (50.0%). Their susceptibility to enrofloxacine (35.0%) as well as gentamicin and tetracycline (30.0%) was markedly lower. The lowest activity was found for lincomycin and neomycin (20.0% of susceptible MRCNS strains, each).

  7. Distribution of serotypes and evaluation of antimicrobial susceptibility among human and bovine Streptococcus agalactiae strains isolated in Brazil between 1980 and 2006

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    Tatiana Castro Abreu Pinto

    Full Text Available Streptococcus agalactiae is a common agent of clinical and subclinical bovine mastitis and an important cause of human infections, mainly among pregnant women, neonates and nonpregnant adults with underlying diseases. The present study describes the genetic and phenotypic diversity among 392 S. agalactiae human and bovine strains isolated between 1980 and 2006 in Brazil. The most prevalent serotypes were Ia, II, III and V and all the strains were susceptible to penicillin, vancomycin and levofloxacin. Resistance to clindamycin, chloramphenicol, erythromycin, rifampicin and tetracycline was observed. Among the erythromycin resistant strains, mefA/E, ermA and, mainly, ermB gene were detected, and a shift of prevalence from the macrolide resistance phenotype to the macrolidelincosamide- streptogramin B resistance phenotype over the years was observed. The 23 macrolide-resistant strains showed 19 different pulsed-field gel electrophoresis profiles. Regarding macrolide resistance, a major concern in S. agalactiae epidemiology, the present study describes an increase in erythromycin resistance from the 80s to the 90s followed by a decrease in the 2000-2006 period. Also, the genetic heterogeneity described points out that erythromycin resistance in Brazil is rather due to horizontal gene transmission than to spreading of specific macrolide-resistant clones.

  8. Susceptibility of chickens, quail, and pigeons to an H7N9 human influenza virus and subsequent egg-passaged strains.

    Science.gov (United States)

    Uchida, Yuko; Kanehira, Katsushi; Takemae, Nobuhiro; Hikono, Hirokazu; Saito, Takehiko

    2017-01-01

    H7N9 human influenza virus A/Anhui/1/2013 (Anhui2013) showed low pathogenicity in chickens, quail, and pigeons, with quail being the most susceptible among the species tested. IVPIE1-1, which was recovered from a dead chicken after intravenous inoculation of Anhui 2013, had broader tissue tropism in chickens than did the original inoculum, as well as amino acid substitutions in the polymerase acidic gene and neuraminidase gene segments, but its pathogenicity was not enhanced. Viruses obtained after passage of Anhui 2013 in 10- and 14-day-old embryonated eggs showed rapid accumulation of amino acid substitutions at the receptor-binding site of the hemagglutinin protein. Two strains obtained through egg passage, 10E4/14E17 and 10E4/10E13, replicated better in intranasally infected chickens than did the original Anhui 2013 strain, yet the new isolates showed low pathogenicity in chickens despite their amino acid substitutions. The increased virus replication in chickens of 10E4/14E17 and 10E4/10E13 was not correlated with temperature-sensitive replication, given that virus replication was suppressed at increased temperatures. The existence of highly susceptible hosts, such as quail, which permit asymptomatic infection, facilitates increased mutation of the virus through amino acid substitution at the receptor-binding site, and this might be one of the mechanisms underlying the prolonged circulation of H7N9 influenza virus.

  9. Tetracycline susceptibility of the ingested Lactobacillus acidophilus LaCH-5 and Bifidobacterium animalis subsp. lactis Bb-12 strains during antibiotic/probiotic intervention.

    Science.gov (United States)

    Saarela, Maria; Maukonen, Johanna; von Wright, Atte; Vilpponen-Salmela, Terttu; Patterson, Andrea J; Scott, Karen P; Hämynen, Heikki; Mättö, Jaana

    2007-03-01

    We investigated the effects of oral therapy with doxycycline, a tetracycline group antibiotic, on the gastrointestinal (GI) survival and tetracycline susceptibility of probiotic strains Lactobacillus acidophilus LaCH-5 and Bifidobacterium animalis subsp. lactis Bb-12. In addition, the influence of doxycycline therapy on the diversity of the predominant faecal microbiota was evaluated by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Faecal samples from the antibiotic group (receiving antibiotics and probiotics) and the control group (receiving probiotics only) were analysed for anaerobically and aerobically growing bacteria, bifidobacteria and lactic acid bacteria as well as for the dominant microbiota. Although doxycycline consumption did not have a large impact on GI survival of the probiotics, it had a detrimental effect on the bifidobacteria and on the diversity of the dominant faecal microbiota. A higher proportion of tetracycline-resistant anaerobically growing bacteria and bifidobacteria was detected in the antibiotic group than in the control group. Several antibiotic group subjects had faecal B. animalis subsp. lactis Bb-12-like isolates with reduced tetracycline susceptibility. This was unlikely to be due to the acquisition of novel tetracycline resistance determinants, since only tet(W), which is also present in the ingested B. animalis subsp. lactis Bb-12, was found in the resistant isolates. Thus, concomitant ingestion of probiotic L. acidophilus LaCH-5 and B. animalis subsp. lactis Bb-12 with the antibiotic did not generate a safety risk regarding the possible GI transfer of tetracycline resistance genes to the ingested strains.

  10. Emergence of a daptomycin-non-susceptible Enterococcus faecium strain that encodes mutations in DNA repair genes after high-dose daptomycin therapy.

    Science.gov (United States)

    Matono, Takashi; Hayakawa, Kayoko; Hirai, Risen; Tanimura, Akira; Yamamoto, Kei; Fujiya, Yoshihiro; Mawatari, Momoko; Kutsuna, Satoshi; Takeshita, Nozomi; Mezaki, Kazuhisa; Ohmagari, Norio; Miyoshi-Akiyama, Tohru

    2016-04-01

    An increasing number of reports have documented the emergence of daptomycin-nonsusceptible Enterococcus in patients during daptomycin therapy. Even though several mechanisms for daptomycin-nonsusceptibility have been suggested, the potential genetic mutations which might contribute to the daptomycin-nonsusceptibility are not fully understood. We isolated a vancomycin-susceptible, daptomycin nonsusceptible Enterococcus faecium strain from a patient with acute lymphocytic leukemia who received high-dose daptomycin therapy for E. faecium endocarditis. Whole-genome sequencing analysis revealed mutations within genes encoding DNA repair proteins MutL and RecJ of the daptomycin-nonsusceptible Enterococcus strain which might have facilitated its emergence. We identified the mutations of DNA mismatch repair genes in a clinical isolate of daptomycin nonsusceptible E. faecium which emerged in spite of high-dose daptomycin therapy. The finding implicates the possible association of DNA repair mechanism and daptomycin resistance. Careful monitoring is necessary to avoid the emergence of daptomycin non-susceptible isolates of E. faecium and particularly in cases of long-term daptomycin use or in immunocompromised patients.

  11. Isolation and determination antimicrobial susceptibility pattern of enterobacter amnigenus biogroup 1 strains isolated from consumed powdered infant formula milk in NICU ward

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    Jalal Mardaneh

    2015-04-01

    Full Text Available Background: Enterobacter amnigenus biogroup 1 is a non-sporeforming, rod-shaped, gram-negative bacterium, within the Enterobacteriaceae family. It is opportunistic pathogen and cause disease humans, especially in premature and immunocompromised persons. The aim of this study was to isolation and determination antimicrobial susceptibility pattern of Enterobacter amnigenus biogroup 1 strains isolated from consumed powdered infant formula (PIF milk in Neonatal Intensive Care Unit (NICU ward. Materials and Methods : In this cross-sectional study, total 125 consumed powdered infant formula milk in NICU ward were surveyed. Isolation and Identification of microorganisms was carried out according to FDA method. Antimicrobial susceptibility test was performed by using the standard disc diffusion method based on CLSI (2011 recommendations. Results: In this study, Enterobacter amnigenus biogroup 1 was isolated from 2 (1.6% of 125 powdered infant formula milk samples. The results showed that isolated strains are sensitive to most antibiotics. All isolates were resistant to amoxicillin and carbenicillin. Conclusion: Contamination of powdered infant formula (PIF samples could have occurred during different steps. It is imperative to prepare the powdered infant formula milk foods according to the manufacturer’s instruction and in an aseptic condition. Contamination of powdered infant formula only could be reduced or prevented by monitoring the critical control points and taking appropriate action during the processing.

  12. Biomphalaria glabrata transcriptome: cDNA microarray profiling identifies resistant- and susceptible-specific gene expression in haemocytes from snail strains exposed to Schistosoma mansoni

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    Rollinson David

    2008-12-01

    Full Text Available Abstract Background Biomphalaria glabrata is an intermediate snail host for Schistosoma mansoni, one of the important schistosomes infecting man. B. glabrata/S. mansoni provides a useful model system for investigating the intimate interactions between host and parasite. Examining differential gene expression between S. mansoni-exposed schistosome-resistant and susceptible snail lines will identify genes and pathways that may be involved in snail defences. Results We have developed a 2053 element cDNA microarray for B. glabrata containing clones from ORESTES (Open Reading frame ESTs libraries, suppression subtractive hybridization (SSH libraries and clones identified in previous expression studies. Snail haemocyte RNA, extracted from parasite-challenged resistant and susceptible snails, 2 to 24 h post-exposure to S. mansoni, was hybridized to the custom made cDNA microarray and 98 differentially expressed genes or gene clusters were identified, 94 resistant-associated and 4 susceptible-associated. Quantitative PCR analysis verified the cDNA microarray results for representative transcripts. Differentially expressed genes were annotated and clustered using gene ontology (GO terminology and Kyoto Encyclopaedia of Genes and Genomes (KEGG pathway analysis. 61% of the identified differentially expressed genes have no known function including the 4 susceptible strain-specific transcripts. Resistant strain-specific expression of genes implicated in innate immunity of invertebrates was identified, including hydrolytic enzymes such as cathepsin L, a cysteine proteinase involved in lysis of phagocytosed particles; metabolic enzymes such as ornithine decarboxylase, the rate-limiting enzyme in the production of polyamines, important in inflammation and infection processes, as well as scavenging damaging free radicals produced during production of reactive oxygen species; stress response genes such as HSP70; proteins involved in signalling, such as importin 7

  13. The blood-stage malaria antigen PfRH5 is susceptible to vaccine-inducible cross-strain neutralizing antibody.

    Science.gov (United States)

    Douglas, Alexander D; Williams, Andrew R; Illingworth, Joseph J; Kamuyu, Gathoni; Biswas, Sumi; Goodman, Anna L; Wyllie, David H; Crosnier, Cécile; Miura, Kazutoyo; Wright, Gavin J; Long, Carole A; Osier, Faith H; Marsh, Kevin; Turner, Alison V; Hill, Adrian V S; Draper, Simon J

    2011-12-20

    Current vaccine strategies against the asexual blood stage of Plasmodium falciparum are mostly focused on well-studied merozoite antigens that induce immune responses after natural exposure, but have yet to induce robust protection in any clinical trial. Here we compare human-compatible viral-vectored vaccines targeting ten different blood-stage antigens. We show that the full-length P. falciparum reticulocyte-binding protein homologue 5 (PfRH5) is highly susceptible to cross-strain neutralizing vaccine-induced antibodies, out-performing all other antigens delivered by the same vaccine platform. We find that, despite being susceptible to antibody, PfRH5 is unlikely to be under substantial immune selection pressure; there is minimal acquisition of anti-PfRH5 IgG antibodies in malaria-exposed Kenyans. These data challenge the widespread beliefs that any merozoite antigen that is highly susceptible to immune attack would be subject to significant levels of antigenic polymorphism, and that erythrocyte invasion by P. falciparum is a degenerate process involving a series of parallel redundant pathways.

  14. Molecular Typing and Antimicrobial Susceptibility of Staphylococcus aureus Strains Isolated from Raw Milk, Cheese, Minced Meat, and Chicken Meat Samples

    OpenAIRE

    CAN,Hayriye Yeşim; Elmal?, Mehmet; Karag?z, Alper

    2017-01-01

    The objectives of this study were: i) to detect the presence of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in raw milk, cheese, beef minced meat, and chicken meat samples; ii) to evaluate the antimicrobial susceptibility of the isolates; and iii) to determine clonal relation among the isolates by using pulsed-field gel electrophoresis (PFGE) method. Therefore, a total of 160 food samples were randomly collected between August 2014 and May 2015 in Hatay province, located ...

  15. Antimicrobial susceptibility of clinical isolates of Actinomyces and related genera reveals an unusual clindamycin resistance among Actinomyces urogenitalis strains.

    Science.gov (United States)

    Barberis, Claudia; Budia, Mabel; Palombarani, Susana; Rodriguez, Carlos Hernán; Ramírez, María Soledad; Arias, Barbara; Bonofiglio, Laura; Famiglietti, Angela; Mollerach, Marta; Almuzara, Marisa; Vay, Carlos

    2017-03-01

    Patterns of antimicrobial susceptibility in Actinomyces and related genera are very limited in the literature. Data of predominant susceptibility profiles could contribute to the establishment of an accurate empirical treatment. A total of 113 isolates from clinical samples were included in this study. Each isolate was identified using phenotypic methods and MALDI-TOF/MS. When discrepancies were observed, 16S rRNA gene sequencing was performed. The minimum inhibitory concentrations (MICs) of nine antimicrobial agents (penicillin, ceftriaxone, linezolid, tetracycline, clindamycin, erythromycin, ciprofloxacin, levofloxacin and vancomycin) were tested against the species Actinotignum schaalii (n=23), Actinomyces turicensis (n=18), Actinomyces europaeus (n=13), Actinomyces naeslundii/Actinomyces viscosus group (n=12), Actinomyces urogenitalis (n=11), Actinomyces radingae (n=11), Actinomyces neuii (n=9), Actinomyces odontolyticus (n=8), Bifidobacterium scardovii (n=3), Actinomyces graevenitzii (n=2), Alloscardovia omnicolens (n=2) and Varibaculum cambriense (n=1). All of the isolates were susceptible to penicillin, ceftriaxone, vancomycin and linezolid. Almost all of the A. urogenitalis isolates (8/11) were resistant to clindamycin and showed susceptibility to erythromycin, suggesting an L-phenotype, however no determinants of clindamycin resistance (lnu and lsa genes) were detected by PCR. High MIC values to quinolones were observed in 54/113 isolates (47.8%). All of the A. urogenitalis isolates were highly resistant to ciprofloxacin and levofloxacin. These data highlight the importance of ongoing surveillance to provide relevant information for empirical management of infections caused by these organisms. Copyright © 2017 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

  16. Effect of Ventilated Caging on Water Intake and Loss in 4 Strains of Laboratory Mice.

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    Nicolaus, Mackenzie L; Bergdall, Valerie K; Davis, Ian C; Hickman-Davis, Judy M

    2016-01-01

    Food availability, temperature, humidity, strain, and caging type all affect water consumption by mice. Measurement of transepidermal water loss (TEWL) is a new technique for the quantification of water turnover in mice. To understand water turnover in common strains of adult mice, male and female SCID, SKH, C57BL/6, and FVB mice were housed in same-sex groups of 5 animals in static cages or IVC. Body weight, TEWL, urine osmolality, and water consumption of mice and intracage temperature and humidity were measured every 48 h for comparison. Static cages were monitored for 7 d and IVC for 14 d before cage change. Female SCID, FVB, and C57 mice drank less water than did their male counterparts. Male and female SCID, SKH, and FVB mice in IVC drank less water and had higher urine osmolality than did those in static cages. In SCID and SKH mice, TEWL paralleled water consumption. C57 mice in static cages drank less water, had lower urine osmolality, and had less TEWL than did those in IVC. Temperature and humidity within the cage was higher than the macroenvironmental levels for all housing conditions, mouse strains, and sexes. Temperatures within IVC ranged from 76.6 to 81.4 °F compared with 69±0.4 °F in the room. Humidity within IVC ranged from 68% to 79% compared with 27.o%±2.7% within the room. These data demonstrate that mouse strain and housing conditions significantly influence water balance and indicate that macroenvironmental measurements do not always reflect the intracage environment.

  17. Effect of different lateral occlusion schemes on peri-implant strain: A laboratory study

    OpenAIRE

    Lo, Jennifer; ABDUO, Jaafar; Palamara, Joseph

    2017-01-01

    PURPOSE This study aims to investigate the effects of four different lateral occlusion schemes and different excursions on peri-implant strains of a maxillary canine implant. MATERIALS AND METHODS Four metal crowns with different occlusion schemes were attached to an implant in the maxillary canine region of a resin model. The included schemes were canine-guided (CG) occlusion, group function (GF) occlusion, long centric (LC) occlusion, and implant-protected (IP) occlusion. Each crown was loa...

  18. In vitro ovicidal and larvicidal activity of methanolic leaf extract of Manihot esculenta (cassava) on susceptible and resistant strains of Trichostrongylus colubriformis.

    Science.gov (United States)

    Al-Rofaai, A; Rahman, W A; Sulaiman, S F; Yahaya, Z S

    2012-11-23

    This study aimed to represent the first report of the ovicidal and larvicidal activity of the methanolic leaf extract of Manihot esculenta (cassava) against eggs and larvae of susceptible and resistant strains of Trichostrongylus colubriformis. As well as, to determine the total tannin compounds, antioxidant activity and toxicity of the extract. The egg hatch test was used to evaluate ovicidal activity against unembryonated eggs, whereas larval feeding inhibition assay and MTT-formazan assay were used to evaluate larvicidal activity against first (L(1)) and infective (L(3)) larvae, respectively. The results showed no significant differences were detected between the sensitivities of susceptible and resistant strains of T. colubriformis to the extract. Eggs, L(1) and L(3) were significantly affected (P<0.001) compared with negative control, and L(1) were more sensitive than the eggs and L(3). The total tannin compounds were investigated using tannin quantification assay and determined by 254.44 TAE/mg. The antioxidant activity was evaluated using the DPPH radical scavenging assay and the median inhibition concentration (IC(50)) was determined by 2.638 mg/ml. Acute oral toxicity at dose of 5,000 mg/kg, and sub-chronic oral toxicity at 500 and 1,000 mg/kg of the extract were observed in male and female Sprague-Dawley (SD) rats. The acute oral toxicity revealed that the median lethal dose (LD(50)) of methanolic extract of cassava leaves on SD rats was greater than 5,000 mg/kg, whereas the sub-chronic oral toxicity did not show observed adverse effects at 500 and 1,000 mg/kg per day for 28 days. In conclusion, the methanolic extract of cassava leaves has direct ovicidal and larvicidal activity against T. colubriformis strains with a safety margin for animals, and it may be potentially utilized as a source of natural antioxidants. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Antimicrobial susceptibilities of Listeria monocytogenes human strains isolated from 1970 to 2008 in Brazil Susceptibilidade antimicrobiana de cepas humanas de Listeria monocytogenes isoladas no período de 1970 a 2008 no Brasil

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    Cristhiane Moura Falavina dos Reis

    2011-04-01

    Full Text Available INTRODUCTION: Listeria monocytogenes is the causative agent of listeriosis, a foodborne illness that affects mainly pregnant women, the elderly and immunocompromised patients. The primary treatment is a combination of ampicillin with an aminoglycoside, in addition to a second-choice drug represented by chloramphenicol, erythromycin, tetracycline and rifampicin. The aim of this study was to analyze the antimicrobial susceptibility profile of strains isolated from human sources in the last four decades. METHODS: Sixty-eight strains were selected from the culture collection of the Laboratory of Bacterial Zoonoses/LABZOO/FIOCRUZ isolated in different regions of Brazil from 1970 to 2008 and primarily isolated from cerebrospinal fluid and blood culture. Susceptibility tests to antimicrobials drugs were evaluated using the criteria established by Soussy using the Kirby-Bauer method and E-Test strips were used to determine the minimum inhibitory concentration (MIC. RESULTS: Among the strains tested, serovar L4b (60.3% was the most prevalent, followed by serovar 1/2a (20.6%, 1/2b (13.2% and the more uncommon serovars 1/2c, 3b and 4ab (5.9%. All strains were susceptible to ampicillin, cephalothin, erythromycin, gentamicin, teicoplanin and vancomycin. Only one strain (1.5% showed resistance to rifampin, and two (3% were resistant to trimethoprim-sulfamethoxazole. MICs with values up to 2μg/ml reinforce the need for microbiological surveillance. CONCLUSIONS: The study demonstrated low prevalence of strains resistant to the antimicrobial drugs indicated in the treatment of human listeriosis. Monitoring antimicrobial resistance profile is still very important to determine adequate treatment, especially in immunocompromised patients.INTRODUÇÃO: Listeria monocytogenes é o agente etiológico da listeriose, doença de origem alimentar que acomete principalmente grávidas, pacientes imunodeprimidos e idosos. O tratamento primário é a associação de

  20. Metabolomic profiling of the response of susceptible and resistant soybean strains to foxglove aphid, Aulacorthum solani Kaltenbach.

    Science.gov (United States)

    Sato, Dan; Akashi, Hiromichi; Sugimoto, Masahiro; Tomita, Masaru; Soga, Tomoyoshi

    2013-04-15

    Aphid infection reduces soybean (Glycine max [L.] Merr.) yield. Consequently, cultivation of aphid-resistant strains is a promising approach to pest control, and understanding the resistance mechanism is of importance. Here, we characterized the resistance of soybeans to foxglove aphid, Aulacorthum solani Kaltenbach, at the metabolite level. First, we evaluated aphid mortality and settlement rates on the leaves of two soybean strains, 'Tohoku149' and 'Suzuyutaka', and found that the former had strong resistance soon after introduction of the aphids. The metabolomic response to aphid introduction was analyzed using capillary electrophoresis-time-of-flight mass spectrometry. We found the following three features in the profiles: (1) concentrations of citrate, amino acids, and their intermediates were intrinsically higher for Tohoku149 than Suzuyutaka, (2) concentrations of several metabolites producing secondary metabolites, such as flavonoids and alkaloids, drastically changed 6h after aphid introduction, and (3) concentrations of TCA cycle metabolites increased in Tohoku149 48 h after aphid introduction. We also profiled free amino acids in aphids reared on both soybean strains and under starvation, and found that the profile of the aphids on Tohoku149 was similar to that of the starved aphids, but different to that of aphids on Suzuyutaka. These tests confirmed that aphids suck phloem sap even from Tohoku149. This study demonstrates the metabolomic profiles of both soybean strains and aphids, which will contribute to the molecular level understanding of mechanisms of soybean resistance to aphids. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Laboratory and field evaluation of an entomopathogenic fungus, Isaria cateniannulata strain 08XS‐1, against Tetranychus urticae (Koch)

    Science.gov (United States)

    Zhang, Xiaona; Zou, Xiao; Guo, Jianjun

    2016-01-01

    Abstract BACKGROUND The two‐spotted mite, Tetranychus urticae Koch, is one of the most serious mite pests of crops throughout the world. Biocontrol of the mite with fungal agents has long been paid much attention because of the development of insecticide resistance and the severe restriction of chemical pesticides. In this study, the efficacy of submerged conidia of the entomopathogenic fungus Isaria cateniannulata strain 08XS‐1 against T. urticae eggs, larvae and female adults was evaluated at different temperatures and humidity in the laboratory and under field conditions. RESULTS The results showed that a suspension of 2 × 107 submerged conidia mL −1 caused the highest mortalities of mite eggs, larvae and females (100, 100 and 70% respectively) at 100% relative humidity and 25 °C in the laboratory. In the field experiments against the mites, a suspension of 2 × 108 submerged conidia mL −1 achieved significant efficiency – the relative control effects were 88.6, 83.8 and 83%, respectively, in cucumber, eggplant and bean fields after 10 days of treatment. CONCLUSION The results suggest that the I. cateniannulata strain 08XS‐1 is a potential fungal agent, with acceptable production cost of conidia, against T. urticae in the field in an area such as southwestern China with higher air humidity. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:26775712

  2. Laboratory and field evaluation of an entomopathogenic fungus, Isaria cateniannulata strain 08XS-1, against Tetranychus urticae (Koch).

    Science.gov (United States)

    Zhang, Xiaona; Jin, Daochao; Zou, Xiao; Guo, Jianjun

    2016-05-01

    The two-spotted mite, Tetranychus urticae Koch, is one of the most serious mite pests of crops throughout the world. Biocontrol of the mite with fungal agents has long been paid much attention because of the development of insecticide resistance and the severe restriction of chemical pesticides. In this study, the efficacy of submerged conidia of the entomopathogenic fungus Isaria cateniannulata strain 08XS-1 against T. urticae eggs, larvae and female adults was evaluated at different temperatures and humidity in the laboratory and under field conditions. The results showed that a suspension of 2 × 10(7) submerged conidia mL(-1) caused the highest mortalities of mite eggs, larvae and females (100, 100 and 70% respectively) at 100% relative humidity and 25 °C in the laboratory. In the field experiments against the mites, a suspension of 2 × 10(8) submerged conidia mL(-1) achieved significant efficiency - the relative control effects were 88.6, 83.8 and 83%, respectively, in cucumber, eggplant and bean fields after 10 days of treatment. The results suggest that the I. cateniannulata strain 08XS-1 is a potential fungal agent, with acceptable production cost of conidia, against T. urticae in the field in an area such as southwestern China with higher air humidity. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  3. In vitro antifungal susceptibility of Malassezia pachydermatis strains isolated from dogs with chronic and acute otitis externa.

    Science.gov (United States)

    Chiavassa, E; Tizzani, P; Peano, A

    2014-10-01

    Malassezia pachydermatis is a yeast that is frequently involved as a secondary/perpetuating factor in canine otitis externa. Topical therapies with different antifungal agents, mainly azole compounds, are generally successful in controlling the yeast overgrowth, but treatment failure and rapid recurrences are common. This study compared the in vitro antifungal susceptibility of M. pachydermatis isolates obtained from chronic and acute cases of otitis externa. The aim was to assess the possible onset of resistance mechanisms in isolates involved in long-lasting episodes with poor response to treatment. We evaluated the in vitro susceptibility to miconazole (MCZ) and clotrimazole (CTZ) of 42 isolates of M. pachydermatis obtained from dogs with chronic (group A, n = 25) and acute otitis (group B, n = 17), using a modified CLSI M27-A3 microdilution method. All isolates were inhibited by the antifungal agents employed, but Malassezia isolates from group A were significantly associated with higher minimum inhibitory concentration (MIC) values for both agents (Median MIC values: MCZ group A 2 µg/ml, group B 1 µg/ml; CTZ group A 8 µg/ml, group B 4 µg/ml). These findings prove that these isolates had a reduced in vitro susceptibility to the antifungal agents tested. However, it is unlikely that this could have any influence on the outcome of a topical treatment. Indeed, marketed products include concentrations of the tested agents that largely exceed even the highest MICs found in this study (in most cases at least 1,000 × the MIC, or greater). In conclusion, this study suggests that isolates of M. pachydermatis involved in chronic cases of canine external otitis and exposed to repeated antifungal treatments are unlikely to develop mechanisms of resistance of clinical relevance.

  4. High incidence of spontaneous cataracts in aging laboratory rabbits of an inbred strain.

    Science.gov (United States)

    Peng, Xuwen; Roshwalb, Sara; Cooper, Timothy K; Zimmerman, Heather; Christensen, Neil D

    2015-05-01

    To investigate the occurrence of spontaneous cataracts in a breeding colony of the inbred EIII/JC strain of New Zealand White rabbits (Oryctolagus cuniculi) and the congenic strain of EIII/JC-HLA-A2.1transgenic rabbits. A retrospective study was conducted by collecting and analyzing data from clinical records for individual rabbits filed between January 2011 and October 2013. Thirteen cases (eight females and five males) of cataract were identified in a group of 51 EIII/JC inbred rabbits with a morbidity of 25.5%. The median age of the rabbits identified with unilateral or bilateral cataracts was 43 months in contrast to the median age of 23 months of the entire group of 51 rabbits. Additionally, seven cases (five females and two males) of cataracts were identified in a group of 21 EIII/JC-HLA-A2.1 transgenic rabbits. The EIII/JC-HLA-A2.1 transgenic rabbits showed similar morbidity (33.3%) and median age (41 months) for the development of cataracts as the EIII/JC rabbits. In both groups, none of the rabbits younger than 37 months developed cataracts while 13 (93%) of 14 EIII/JC rabbits aged 37-49 months and seven (63.6%) of 11 EIII/JC-HLA-A2.1 transgenic rabbits aged 37-43 months developed cataracts. In contrast, none of 78 outbred rabbits with a median age of 26 months (10-67 months) developed cataracts. Results of this study indicate that the occurrence and high incidence of spontaneous cataracts in this inbred strain (EIII/JC) of rabbits were strictly age related and consistently transmitted through inbreeding. © 2014 American College of Veterinary Ophthalmologists.

  5. Prolonged job strain reduces time-domain heart rate variability on both working and resting days among cardiovascular-susceptible nurses

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    Rossana Borchini

    2015-02-01

    Full Text Available Introduction Modifications of hearth rate variability (HRV constitute a marker of the autonomic nervous system (ANS deregulation, a promising pathway linking job strain (JS and cardiovascular diseases (CVD. The study objective is to assess whether exposures to recent and prolonged JS reduce time-domain HRV parameters on working days (WD among CVD-susceptible nurses and whether the association also persists on resting days (RD. Material and methods 313 healthy nurses were investigated twice with one year interval to assess JS based on the demand-control and the effort-reward models. 36, 9 and 16 CVD-susceptible nurses were classified as low JS in both surveys (stable low strain – SLS, recent high JS (high JS at the second screening only-RHS and prolonged high JS (high strain in both surveys-PHS, respectively. In 9, 7 and 10 of them, free from comorbidities/treatments interfering with HRV, two 24-h ECG recordings were performed on WD and RD. Differences in the time domain HRV metrics among JS categories were assessed using ANCOVA, adjusted for age and smoking. Results In the entire sample (mean age: 39 years, 83% females the prevalence of high job strain was 38.7% in the second survey. SDNN (standard deviation of all normal RR intervals on WD significantly declined among JS categories (p = 0.02, with geometric mean values of 169.1, 145.3 and 128.9 ms in SLS, RHS, PHS, respectively. In the PHS group, SDNN remained lower on RD as compared to the low strain subjects (142.4 vs. 171.1 ms, p = 0.02. Similar findings were found for the SDNN_Index, while SDANN (standard deviation of average RR intervals in all 5 min segments of registration mean values reduced in the PHS group during WD only. Conclusions Our findings suggest that persistent JS lowers HRV time-domain parameters, supporting the hypothesis that the ANS disorders may play an intermediate role in the relationship between work stress and CVD.

  6. Prolonged job strain reduces time-domain heart rate variability on both working and resting days among cardiovascular-susceptible nurses.

    Science.gov (United States)

    Borchini, Rossana; Bertù, Lorenza; Ferrario, Marco M; Veronesi, Giovanni; Bonzini, Matteo; Dorso, Marco; Cesana, Giancarlo

    2015-01-01

    Modifications of hearth rate variability (HRV) constitute a marker of the autonomic nervous system (ANS) deregulation, a promising pathway linking job strain (JS) and cardiovascular diseases (CVD). The study objective is to assess whether exposures to recent and prolonged JS reduce time-domain HRV parameters on working days (WD) among CVD-susceptible nurses and whether the association also persists on resting days (RD). 313 healthy nurses were investigated twice with one year interval to assess JS based on the demand-control and the effort-reward models. 36, 9 and 16 CVD-susceptible nurses were classified as low JS in both surveys (stable low strain - SLS), recent high JS (high JS at the second screening only-RHS) and prolonged high JS (high strain in both surveys-PHS), respectively. In 9, 7 and 10 of them, free from comorbidities/treatments interfering with HRV, two 24-h ECG recordings were performed on WD and RD. Differences in the time domain HRV metrics among JS categories were assessed using ANCOVA, adjusted for age and smoking. In the entire sample (mean age: 39 years, 83% females) the prevalence of high job strain was 38.7% in the second survey. SDNN (standard deviation of all normal RR intervals) on WD significantly declined among JS categories (p = 0.02), with geometric mean values of 169.1, 145.3 and 128.9 ms in SLS, RHS, PHS, respectively. In the PHS group, SDNN remained lower on RD as compared to the low strain subjects (142.4 vs. 171.1 ms, p = 0.02). Similar findings were found for the SDNN_Index, while SDANN (standard deviation of average RR intervals in all 5 min segments of registration) mean values reduced in the PHS group during WD only. Our findings suggest that persistent JS lowers HRV time-domain parameters, supporting the hypothesis that the ANS disorders may play an intermediate role in the relationship between work stress and CVD. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  7. The differential interferon responses of two strains of Stat1-deficient mice do not alter susceptibility to HSV-1 and VSV in vivo.

    Science.gov (United States)

    Katzenell, Sarah; Chen, Yufei; Parker, Zachary M; Leib, David A

    2014-02-01

    Stat1 is a pivotal transcription factor for generation of the interferon (IFN)-dependent antiviral response. Two Stat1 knockout mouse lines have been previously generated, one deleted the N-terminal domain (ΔNTD) and one in the DNA-binding domain (ΔDBD). These widely-used strains are assumed interchangeable, and both are highly susceptible to various pathogens. In this study, primary cells derived from ΔNTD mice were shown to be significantly more responsive to IFN, and established an antiviral state with greater efficiency than cells derived from ΔDBD mice, following infection with vesicular stomatitis virus and herpes simplex virus type-1. Also, while mice from both strains succumbed rapidly and equally to virus infection, ΔDBD mice supported significantly higher replication in brains and livers than ΔNTD mice. Endpoint-type experimental comparisons of these mouse strains are therefore misleading in failing to indicate important differences in virus replication and innate response. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. In vitro activity of neem (Azadirachta indica) and cassava (Manihot esculenta) on three pre-parasitic stages of susceptible and resistant strains of Teladorsagia (Ostertagia) circumcincta.

    Science.gov (United States)

    Al-Rofaai, A; Rahman, W A; Sulaiman, S F; Yahaya, Z S

    2012-08-13

    Anthelmintic resistance of gastrointestinal nematodes is considered as one of the main limiting factors causing significant economic losses to the small ruminant industry. The anthelmintic properties of some plants are among the suggested alternative solutions to control these parasitic worms. The present study investigated the anthelmintic activity of neem (Azadirachta indica) and cassava (Manihot esculenta) leaf extracts against the susceptible and resistant strains of one of the most important nematodes in small ruminants, Teladorsagia (Ostertagia) circumcincta. Three different in vitro tests: egg hatch test, larval development assay, and larval paralysis assay were used to determine the efficiency of neem and cassava extracts on three pre-parasitic stages of T. circumcincta. The LC(50) was determined for the most potent extract in each plant as well as the phytochemical tests, total tannin quantification and cytotoxicity on peripheral blood mononuclear cells of goats. The results revealed a high anthelmintic activity of neem methanol extract (NME) and cassava methanol extract (CME) on both strains of T. circumcincta without significant differences between the strains. The first stage larvae were more sensitive with the lowest LC(50) at 7.15 mg/ml and 10.72 mg/ml for NME and CME, respectively, compared with 44.20mg/ml and 56.68 mg/ml on eggs and 24.91 mg/ml and 71.96 mg/ml on infective stage larvae. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Hemagglutinins in Anopheles quadrimaculatus, strains susceptible and refractory to Brugia malayi, and their role in the immune response to filarial parasites.

    Science.gov (United States)

    Nayar, J K; Knight, J W

    1997-01-01

    Hemagglutinins in the salivary gland extract and in the body fluid from strains of the mosquito, Anopheles quadrimaculatus, susceptible and refractory to the filarial parasite, Brugia malayi, had higher titers against Human A+, B- and O+, and sheep erythrocytes than against rabbit and jird erythrocytes. Hemagglutination activity in the body fluid was low in newly emerged females but increased and stabilized as they became older. Hemagglutination activity of the body fluid was not reduced by freezing at -20 degrees C, but it was destroyed following heating the body fluid to 60 degrees C and 100 degrees C for 45 min, indicating that the hemagglutinins are heat labile, and they are proteins or glycoproteins. Hemagglutinins in the salivary glands exhibited specificities for a broader range of carbohydrate moieties on the surface of Human A+ and sheep erythrocytes than those in the body fluid. Injections of specific carbohydrates in saline solution into B. malayi-infected females of the refractory strain of An. quadrimaculatus 24 hr after the infective blood meal showed that galactose, N-acetyl-D-galacto-samine, sorbose and mannose inhibited the increase in encapsulation (melanization) of L1 of B. malayi in the thoracic muscles of An. quadrimaculatus females when compared to those females injected with saline and other carbohydrates. The results suggest that hemagglutinins are present in the salivary gland extract and the body fluid of both strains of An. quadrimaculatus females and they may be involved in the immune response (encapsulation) to filarial parasites in An. quadrimaculatus.

  10. Comparative Transcriptome Analysis of Bombyx mori (Lepidoptera Larval Midgut Response to BmNPV in Susceptible and Near-Isogenic Resistant Strains.

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    Xue-Yang Wang

    Full Text Available Bombyx mori nucleopolyhedrovirus (BmNPV is one of the primary pathogens causing severe economic losses in sericulture. However, the molecular mechanism of silkworm resistance to BmNPV remains largely unknown. Here, the recurrent parent P50 (susceptible strain and the near-isogenic line BC9 (resistance strain were used in a comparative transcriptome study examining the response to infection with BmNPV. A total of 14,300 unigenes were obtained from two different resistant strains; of these, 869 differentially expressed genes (DEGs were identified after comparing the four transcriptomes. Many DEGs associated with protein metabolism, cytoskeleton, and apoptosis may be involved in the host response to BmNPV infection. Moreover, some immunity related genes were also altered following BmNPV infection. Specifically, after removing genetic background and individual immune stress response genes, 22 genes were found to be potentially involved in repressing BmNPV infection. These genes were related to transport, virus replication, intracellular innate immune, and apoptosis. Our study provided an overview of the molecular mechanism of silkworm resistance to BmNPV infection and laid a foundation for controlling BmNPV in the future.

  11. Lifetime Dependent Variation of Stress Hormone Metabolites in Feces of Two Laboratory Mouse Strains.

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    Thomas Kolbe

    Full Text Available Non-invasive measurement of stress hormone metabolites in feces has become routine practice for the evaluation of distress and pain in animal experiments. Since metabolism and excretion of glucocorticoids may be variable, awareness and adequate consideration of influencing factors are essential for accurate monitoring of adrenocortical activity. Reference values are usually provided by baselines compiled prior to the experiment and by age matched controls. The comparison of stress hormone levels between animals of different ages or between studies looking at hormone levels at the beginning and at the end of a long term study might be biased by age-related effects. In this study we analyzed fecal corticosterone metabolites (FCM during the lifetime of untreated female mice of the strains C57BL/6NCrl and Crl:CD1. For this purpose feces for each individual mouse were collected every two months over a period of 24 hours, at intervals of four hours, until the age of 26 months. Results of the study revealed that age of the animals had a significant impact on the level and circadian rhythm of stress hormone metabolites. Furthermore, long-term observation of mice revealed a strain specific excretion profile of FCM influenced by strong seasonal variability.

  12. Epidemiology and Drug Susceptibility of Pseudomonas aeruginosa Strains isolated from Patients admitted to Zabol hospitals: Short Communication

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    Forough Heydari

    2015-12-01

    Full Text Available Background and Aim: Pseudomonas aeruginosa is one of the most important causative agents of nosocomial infections that threatens many lives .. Regarding the innate and adaptive ability of the bacteria species to become resistant to many antimicrobial agents, recognition of different antibiotic resistance patterns is extremely significant in assessing the validity of the monitoring programs. Also, the pattern of genetic isolates is essential in the management of infections caused by these bacteria. The purpose of this study was to determine genetic diversity and patterns of antimicrobial resistance of P. aeruginosa isolates using RAPD-PCR. Materials and Methods: The present study aimed at assessing the genetic diversity and antibiotic resistant pattern of P. aeruginosa isolates in the educational Zabol hospitals. Thus, antibiotic susceptibility of 100 isolates was determined applying Kirby-Bauer disk diffusion method. Results: RAPD-PCR data revealed  a high level of polymorphism among the isolates of P. aeruginosa in Sistan. But, no association was observed between antibiotic susceptibility and genetic diversity pattern. Conclusion: In the present study, we RAPD-PCR technique was found to be a useful means for the investigation of the genetic variation and epidemiological study among P. aeruginosa isolates collected from Sistan region.

  13. Susceptibility of carbapenemase-producing strains of Klebsiella pneumoniae and Escherichia coli to the direct antibacterial activity of NAB739 and to the synergistic activity of NAB7061 with rifampicin and clarithromycin.

    Science.gov (United States)

    Vaara, Martti; Siikanen, Osmo; Apajalahti, Juha; Frimodt-Møller, Niels; Vaara, Timo

    2010-05-01

    To determine the susceptibility of carbapenemase-producing strains of Klebsiella pneumoniae and Escherichia coli to the direct antibacterial activity of NAB739 and to the synergistic activity of NAB7061 with rifampicin and clarithromycin. NAB739 and NAB7061 are novel polymyxin derivatives that lack the cationic charges in the linear peptide portion of polymyxin B and have pharmacokinetic properties different from those of polymyxin B. MIC determinations were performed by the agar dilution method using CLSI guidelines. Polymyxin B was used as a comparison. Synergism studies measured fractional inhibitory concentration indices (FICIs) by using increasing concentrations of the compounds in Mueller-Hinton agar and Etests. The MICs of NAB739 for all nine polymyxin-susceptible, carbapenemase-producing strains were identical or very close to those determined for E. coli ATCC 25922, for K. pneumoniae ATCC 13883, as well as for 18 clinical carbapenem-susceptible isolates. At a concentration of 4 mg/L, NAB7061 decreased the MIC of rifampicin and clarithromycin for all carbapenemase strains by factors ranging from 6 to 500. The polymyxin-resistant strain K. pneumoniae CL5762B was sensitized by a factor of 24 to rifampicin (FICI, 0.167) and by a factor of 12 to clarithromycin (FICI, 0.208). Polymyxin-susceptible, carbapenemase-producing strains are as susceptible to NAB739 as are the carbapenem-susceptible clinical isolates. In addition, NAB7061 has notable synergism with rifampicin and clarithromycin against all the carbapenemase-producing strains tested, including the polymyxin-resistant K. pneumoniae strain.

  14. Escherichia coli Strains Isolated from the Uteri Horn, Mouth, and Rectum of Bitches Suffering from Pyometra: Virulence Factors, Antimicrobial Susceptibilities, and Clonal Relationships among Strains

    Science.gov (United States)

    Agostinho, Juliana M. A.; de Souza, Andressa; Schocken-Iturrino, Ruben P.; Beraldo, Lívia G.; Borges, Clarissa A.; Ávila, Fernando A.; Marin, José M.

    2014-01-01

    Pyometra is recognized as one of the main causes of disease and death in the bitch, and Escherichia coli is the major pathogen associated with this disease. In this study, 70 E. coli isolates from the uteri horn, mouth, and rectum of bitches suffering from the disease and 43 E. coli isolates from the rectum of clinically healthy bitches were examined for the presence of uropathogenic virulence genes and susceptibility to antimicrobial drugs. DNA profiles of isolates from uteri horn and mouth in bitches with pyometra were compared by REP, ERIC, and BOX-PCR. Virulence gene frequencies detected in isolates from canine pyometra were as follows: 95.7% fim, 27.1% iss, 25.7% hly, 18.5% iuc, and 17.1% usp. Predominant resistance was determined for cephalothin, ampicillin, and nalidixic acid among the isolates from all sites examined. Multidrug resistance was found on ∼50% pyometra isolates. Using the genotypic methods some isolates from uteri, pus, and saliva of the same bitch proved to have identical DNA profiles which is a reason for concern due to the close relationship between household pets and humans. PMID:24734047

  15. Escherichia coli Strains Isolated from the Uteri Horn, Mouth, and Rectum of Bitches Suffering from Pyometra: Virulence Factors, Antimicrobial Susceptibilities, and Clonal Relationships among Strains

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    Juliana M. A. Agostinho

    2014-01-01

    Full Text Available Pyometra is recognized as one of the main causes of disease and death in the bitch, and Escherichia coli is the major pathogen associated with this disease. In this study, 70 E. coli isolates from the uteri horn, mouth, and rectum of bitches suffering from the disease and 43 E. coli isolates from the rectum of clinically healthy bitches were examined for the presence of uropathogenic virulence genes and susceptibility to antimicrobial drugs. DNA profiles of isolates from uteri horn and mouth in bitches with pyometra were compared by REP, ERIC, and BOX-PCR. Virulence gene frequencies detected in isolates from canine pyometra were as follows: 95.7% fim, 27.1% iss, 25.7% hly, 18.5% iuc, and 17.1% usp. Predominant resistance was determined for cephalothin, ampicillin, and nalidixic acid among the isolates from all sites examined. Multidrug resistance was found on ∼50% pyometra isolates. Using the genotypic methods some isolates from uteri, pus, and saliva of the same bitch proved to have identical DNA profiles which is a reason for concern due to the close relationship between household pets and humans.

  16. Comparative study on the antibiotic susceptibility and plasmid profiles of Vibrio alginolyticus strains isolated from four Tunisian marine biotopes.

    Science.gov (United States)

    Lajnef, Rim; Snoussi, Mejdi; Romalde, Jesús López; Nozha, Cohen; Hassen, Abdennaceur

    2012-12-01

    The antibiotic resistance patterns and the plasmids profiles of the predominant etiological agent responsible for vibriosis in Tunisia, V. alginolyticus were studied to contribute to control their spread in some Mediterranean aquaculture farms and seawater. The sixty-nine V. alginolyticus strains isolated from different marine Tunisian biotopes (bathing waters, aquaculture and conchylicole farms and a river connected to the seawater during the cold seasons) were multi-drug resistant with high resistance rate to ampicillin, kanamycin, doxycyclin, erythromycin, imipinem, and nalidixic acid. The multiple resistance index ranged from 0.3 to 0.7 for the isolates of Khenis, from 0.5 to 0.8 for those of Menzel Jmil, from 0.5 to 0.75 (Hergla) and from 0.3 to 0.7 for the isolates of Oued Soltane. The high value of antibiotic resistance index was recorded for the V. alginolyticus population isolated from the fish farm in Hergla (ARI = 0.672) followed by the population isolated from the conchylicole station of Menzel Jmil (ARI = 0.645). The results obtained by the MIC tests confirmed the resistance of the V. alginolyticus to ampicillin, erythromycin, kanamycin, cefotaxime, streptomycin and trimethoprim. Plasmids were found in 79.48 % of the strains analyzed and 30 different plasmid profiles were observed. The strains had a high difference in the size of plasmids varying between 0.5 and 45 kb. Our study reveals that the antibiotic-resistant bacteria are widespread in the aquaculture and conchylicole farm relatively to others strains isolated from seawater.

  17. pH-induced change in cell susceptibility to butanol in a high butanol-tolerant bacterium, Enterococcus faecalis strain CM4A.

    Science.gov (United States)

    Kanno, Manabu; Tamaki, Hideyuki; Mitani, Yasuo; Kimura, Nobutada; Hanada, Satoshi; Kamagata, Yoichi

    2015-01-01

    Though butanol is considered as a potential biofuel, its toxicity toward microorganisms is the main bottleneck for the biological butanol production. Recently, butanol-tolerant bacteria have been proposed as alternative butanol production hosts overcoming the end product inhibition. One remaining key issue to be addressed is how physicochemical properties such as pH and temperature affect microbial butanol tolerance during cultivation and fermentation. We investigated the pH effect on butanol tolerance of a high butanol-tolerant bacterium, Enterococcus faecalis strain CM4A. The strain grew over a broad pH range (pH 4.0 to 12.0) and preferred alkaline pH (pH 8.0 and 10.0) in the absence of butanol. However, in the presence of butanol, strain CM4A grew better under acidic and neutral pH conditions (pH 6.0 and 6.8). Membrane fatty acid analysis revealed that the cells exposed to butanol exhibited increased cyclopropane and saturated fatty acids, which contribute to butanol tolerance of the strain by decreasing membrane fluidity, more evidently at acidic and neutral pH than at alkaline pH. Meanwhile, the strain grown under alkaline pH without butanol increased short chain fatty acids, which is involved in increasing membrane fluidity for alkaline adaptation. Such a change was not observed in the cells grown under alkaline pH with butanol. These results suggested that strain CM4A simultaneously exposed to butanol and alkali stresses was not likely able to properly adjust membrane fluidity due to the opposite response to each stress and thereby showed low butanol tolerance under alkaline pH. Indeed, the cells exposed to butanol at alkaline pH showed an irregular shape with disrupted membrane structure under transmission electron microscopy observation, which also indicated the impact of butanol and alkali stresses on functioning of cellular membrane. The study clearly demonstrated the alkaline pH-induced increase of cell susceptibility to butanol in the tested strain

  18. D-Alanine-Controlled Transient Intestinal Mono-Colonization with Non-Laboratory-Adapted Commensal E. coli Strain HS.

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    Miguelangel Cuenca

    Full Text Available Soon after birth the mammalian gut microbiota forms a permanent and collectively highly resilient consortium. There is currently no robust method for re-deriving an already microbially colonized individual again-germ-free. We previously developed the in vivo growth-incompetent E. coli K-12 strain HA107 that is auxotrophic for the peptidoglycan components D-alanine (D-Ala and meso-diaminopimelic acid (Dap and can be used to transiently associate germ-free animals with live bacteria, without permanent loss of germ-free status. Here we describe the translation of this experimental model from the laboratory-adapted E. coli K-12 prototype to the better gut-adapted commensal strain E. coli HS. In this genetic background it was necessary to complete the D-Ala auxotrophy phenotype by additional knockout of the hypothetical third alanine racemase metC. Cells of the resulting fully auxotrophic strain assembled a peptidoglycan cell wall of normal composition, as long as provided with D-Ala and Dap in the medium, but could not proliferate a single time after D-Ala/Dap removal. Yet, unsupplemented bacteria remained active and were able to complete their cell cycle with fully sustained motility until immediately before autolytic death. Also in vivo, the transiently colonizing bacteria retained their ability to stimulate a live-bacteria-specific intestinal Immunoglobulin (IgA response. Full D-Ala auxotrophy enabled rapid recovery to again-germ-free status. E. coli HS has emerged from human studies and genomic analyses as a paradigm of benign intestinal commensal E. coli strains. Its reversibly colonizing derivative may provide a versatile research tool for mucosal bacterial conditioning or compound delivery without permanent colonization.

  19. Species distribution and susceptibility profile of yeasts isolated from blood cultures: results of a multicenter active laboratory-based surveillance study in Argentina.

    Science.gov (United States)

    Córdoba, Susana; Vivot, Walter; Bosco-Borgeat, Maria E; Taverna, Constanza; Szusz, Wanda; Murisengo, Omar; Isla, Guillermina; Davel, Graciela

    2011-01-01

    The Mycology Department of the Instituto Nacional de Enfermedades Infecciosas "Dr. C. Malbrán", conducted the Second National Multicenter Survey on Fungemia due to Yeasts in Argentina. The aim was to obtain updated data of the frequency of the causative species encountered and their in vitro susceptibility to seven antifungal agents. Yeast species were identified by micromorphological and biochemical studies. Antifungal susceptibility testing was performed by the reference microdilution method E.Def 7.1 of the European Committee on Antibiotic Susceptibility Testing (EUCAST). A total of 461 viable yeasts were identified. The most frequent species were: Candida albicans (38.4 %), Candida parapsilosis (26 %), Candida tropicalis (15.4 %) and Candida glabrata (4.3 %). Other uncommon species, such as Candida viswanathii (0.6 %), Candida haemulonii (0.4 %), Candida inconspicua (0.2 %) and Candida fermentati (0.2 %) were also isolated. Among the Candida spp., 5.4 % and 1.6 % were resistant to fluconazole and voriconazole, respectively. Itraconazole and caspofungin were the most efficient agents against all Candida spp. tested (MIC 8 mg/l), 75 % of Trichosporon spp., and 100 % of Rhodotorula spp., Geotrichum candidum, Saccharomyces cerevisiae. The global percentage of mortality was 20 %. The presence of uncommon species reinforces the need for performing continuous laboratory surveillance in order to monitor possible changes, not only in the epidemiological distribution of species, but also in the resistance to antifungal drugs.

  20. In vitro activity of the new fluoroketolide solithromycin (CEM-101) against macrolide-resistant and -susceptible Mycoplasma genitalium strains.

    Science.gov (United States)

    Jensen, Jørgen Skov; Fernandes, Prabhavathi; Unemo, Magnus

    2014-06-01

    Mycoplasma genitalium has become well established as an etiological agent of sexually transmitted infections, but due to its fastidious growth requirements, only a few M. genitalium strains are available to determine the MICs of currently used and new antimicrobial agents. Recent clinical trials have suggested that treatment with azithromycin has decreasing efficacy due to an increasing prevalence of macrolide resistance, and alternative treatment with moxifloxacin is similarly under pressure from emerging resistance. Thus, there is an urgent need for new antimicrobials. The in vitro activity of the newly developed fluoroketolide solithromycin (CEM-101) was evaluated against a collection of 40 M. genitalium strains, including 15 with high-level macrolide resistance and 5 multidrug-resistant strains with resistance to both macrolides and quinolones. Furthermore, the MIC of solithromycin was correlated with mutations in the 23S rRNA gene and in the genes encoding ribosomal proteins L4 and L22. The in vitro results showed that solithromycin has activity against M. genitalium superior to that of other macrolides, doxycycline, and fluoroquinolones. Accordingly, this new fluoroketolide might be an effective option for treatment of M. genitalium infections. However, the efficacy of solithromycin in clinical trials with follow-up for test of cure and detection of genotypic and phenotypic resistance needs to be evaluated prior to widespread use. In a phase 2 clinical trial, solithromycin was highly effective as a single oral dose against C. trachomatis and Neisseria gonorrhoeae, suggesting that solithromycin could be a treatment option for several sexually transmitted infections, including in syndromic treatment of urethral and vaginal discharge. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  1. Disinfectant-susceptibility of multi-drug-resistant Mycobacterium tuberculosis isolated in Japan

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    Noriko Shinoda

    2016-02-01

    Full Text Available Abstract Background Multi-drug-resistant Mycobacterium tuberculosis has been an important problem in public health around the world. However, limited information about disinfectant-susceptibility of multi-drug-resistant strain of M. tuberculosis was available. Findings We studied susceptibility of several Japanese isolates of multi-drug-resistant M. tuberculosis against disinfectants, which are commonly used in clinical and research laboratories. We selected a laboratory reference strain (H37Rv and eight Japanese isolates, containing five drug-susceptible strains and three multi-drug-resistant strains, and determined profiles of susceptibility against eight disinfectants. The M. tuberculosis strains were distinguished into two groups by the susceptibility profile. There was no relationship between multi-drug-resistance and disinfectant-susceptibility in the M. tuberculosis strains. Cresol soap and oxydol were effective against all strains we tested, regardless of drug resistance. Conclusions Disinfectant-resistance is independent from multi-drug-resistance in M. tuberculosis. Cresol soap and oxydol were effective against all strains we tested, regardless of drug resistance.

  2. Comparison of outcome and clinical characteristics of bacteremia caused by methicillin-resistant, penicillin-resistant and penicillin-susceptible Staphylococcus aureus strains.

    Science.gov (United States)

    Jokinen, Elina; Laine, Janne; Huttunen, Reetta; Rahikka, Pekka; Huhtala, Heini; Vuento, Risto; Vuopio, Jaana; Syrjänen, Jaana

    2017-07-01

    The aim of this study was to assess the association of methicillin resistance and penicillinase production with clinical characteristics and outcome of Staphylococcus aureus bacteremia. For 126 patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, 378 age- and gender-matched controls with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia were selected. Of controls, 126 had bacteremia caused by penicillin-susceptible strains (PSSA) and 252 by penicillinase-producing strains (PRSA). Underlying diseases, clinical course and mortality were retrospectively assessed. Patients with MRSA bacteremia were more often smokers than patients with MSSA bacteremia (OR 2.34, 95% CI 1.27-4.32). MRSA bacteremia was more often healthcare-associated (OR 4.23, 95% CI 2.47-7.24), associated with central venous catheters (OR 2.09, 95% CI 1.27-3.47), glucocorticoid therapy (OR 1.82, 95% CI 1.12-2.93) and prior surgery (OR 2.32, 95% CI 1.43-3.76). Patients with MRSA bacteremia received appropriate empiric antibiotic (31%) less often than controls (98%). Mortality within 28 days was higher in MRSA bacteremia (26.8%) than in MSSA bacteremia (15.5%) (OR 2.00, 95% CI 1.20-3.34), PRSA bacteremia (17.0%) (OR 1.79 95% CI 1.04-3.09) or PSSA bacteremia (12.5%) (OR 2.56 95% CI 1.27-5.15). The difference remained after adjusting for underlying diseases and foci. There was no significant difference in clinical course between PRSA and PSSA bacteremias. MRSA bacteremia was associated with poorer outcome than either PRSA or PSSA bacteremia. We corroborated several risk factors found in previous studies.

  3. Antifungal susceptibility testing of Candida in the Clinical Laboratory: how to do it, when to do it, and how to interpret it

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    Esther Manso

    2014-06-01

    Full Text Available Significant changes in the management of fungaemia have occurred in the last decade with increased use of fluconazole prophylaxis, of empirical treatment and of echinocandins as first-line agents for documented disease. The emergence of drug resistance in fungal pathogens has a profound impact on human health given limited number of antifungal drugs. Antifungal resistance in Candida may be either intrinsic or acquired and may be encountered in the antifungal drug exposed but also the antifungal drug naïve patient The variation in resistance rates between centers emphasizes that it is essential to have knowledge of the local Candida species distribution and antifungal resistance rates to guide initial therapy for Candida BSI. Moreover, all Candida isolates from blood and normally sterile sites should be identified to the species level. The Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing have developed breakpoints and epidemiological cutoff values that are now established for Candida spp. Clinical microbiology laboratories will be employed commercial susceptibility assays, rather than reference broth microdilution methods and comparative studies are particularly important. Vitek 2®, Etest® and Sensititre YeastOne® provided a high degree of essential agreement and comparable sensitivity and specificity to BMD-RPMI for identifying resistance to azole and echinocandins in Candida spp.

  4. SUSCEPTIBILIDADE ANTIMICROBIANA DE AMOSTRAS DE Salmonella Enteritidis ISOLADAS DE DIFERENTES FONTES ANTIMICROBIAL SUSCEPTIBILITY OF Salmonella Enteritidis STRAINS FROM DIFFERENT SOURCES

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    Iolanda A. Nunes

    2009-04-01

    Full Text Available A susceptibilidade antimicrobiana de Salmonella Enteritidis é descrita em amostras isoladas de galinhas saudáveis e doentes, casos esporádicos de gastrenterite humana relacionadas ao consumo de produtos contendo ovos, carne de frango, ovos bicados, farinha de carne/ambiente de avicultura, fezes de suínos e alimentos. No período de 1995 a 1997 foi observado que 72,2% foram sensíveis, enquanto que 9,2% e 17,8% foram resistentes e intermediárias, respectivamente. Constatou-se resistência em 6,2% das isoladas do homem, 5,0% de carnes de frangos, 36,4% de alimentos, 4,2% de galinhas, 23,7% de ovos bicados, 5,7% de farinha de carne/ambiente de avicultura e 13,3% de suínos. Os resultados obtidos revelaram elevada proporção de amostras com sensibilidade intermediária (18,1% do total e 100% de sensibilidade a seis princípios. Considerando as amostras resistentes, quinze (57,7% apresentaram resistência única a nove antimicrobianos. Quatro (15,4% (galinhas e ovos bicados apresentaram resistência dupla; resistência tripla foi detectada em uma amostra (3,8%, enquanto que seis (23,1% apresentaram seis perfis de multirresistência, frente a 4-9 drogas, identificados em amostras do homem, alimentos, galinhas e ovos bicados. Embora o índice de resistência aqui descrito possa ser considerado baixo, deve ser destacada a alta frequência de sensibilidade intermediária à tetraciclina, particularmente em amostras associadas a aves.

    PALAVRAS-CHAVES: Alimentos, galinhas, gastrenterite humana, multirresistência a antibióticos.
    Enteritidisin the period from 1995 to 1997 is described in strains isolated from healthy and ill chickens, human sporadic gastrenteritis outbreaks related to egg products consumption, poultry meats, broiler chicken pipped embryos, meat meal/aviculture environment, swine feces and foods (cheese, mayonnaise, cake mass, cake cover and bacon. It was observed that 72.2% were sensitive, whereas 9.2% and 17.8% were

  5. Strongyloides venezuelensis infection susceptibility of seven inbred strains of mice Susceptibilidade de sete linhagens isogênicas de camundongos à infecções por Strongyloides venezuelensis

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    A.F.T. Amarante

    2002-06-01

    Full Text Available A trial was carried out to investigate the susceptibility of seven strains of mice to Strongyloides venezuelensis primary and secondary experimental infections, in order to provide the basis for genetic studies about resistance. Twelve six-week-old male inbred mice of the A/J, BALB/c, CBA/J, C3H/Hepos, C57BL/6, DBA/2 and NIH strains were infected s.c. with 2000 infective larvae. The mean worm counts (± SD in the small intestine six days after infection were, in increasing order: 28 (± 19 in NIH; 647 (± 228 in BALB/c; 709 (± 425 in DBA/2; 731 (± 151 in C3H/Hepos, 801 (± 174 in CBA/J; 1024 (± 267 in C57BL/6 and 1313 (± 483 in A/J. C57BL/6 mice showed the highest fecal egg counts and NIH, the lowest. No eggs in fecal exams or nematodes in small intestines were recovered from animals reinfected 14 days after primary infection. NIH strain was highly resistant to primary infection by S. venezuelensis. The most susceptible of the other six strains appeared to be the C57BL/6 strain which presented a high nematode counting in intestine and the highest egg output.Foi investigada a susceptibilidade de sete linhagens isogênicas de camundongos à infecção experimental, primária e secundária, por Strongyloides venezuelensis a fim de servir de base para estudos genéticos sobre a resistência. Foram utilizados 12 camundongos machos, com seis semanas de idade, das seguintes linhagens isogênicas: A/J, BALB/c, CBA/J, C3H/Hepos, C57BL/6, DBA/2 e NIH. Os animais foram inoculados, via sub-cutânea, com 2000 larvas infectantes. As contagens médias (± desvio padrão de parasitas no intestino delgado dos camundongos seis dias após a infecção, em ordem crescente, foram: 28 (± 19 na linhagem NIH; 647 (± 228 na BALB/c; 709 (± 425 na DBA/2; 731 (± 151 na C3H/Hepos, 801 (± 174 na CBA/J; 1024 (± 267 na C57BL/6 e 1313 (± 483 na A/J. Os camundongos C57BL/6 apresentaram as mais elevadas contagens de ovos de S. venezuelensis por grama de fezes (OPG e os

  6. The antimicrobial susceptibility profile of ESKAPE pathogens from urinary tract infections in a referral laboratory, Northeast Iran

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    Mohammad Salehi

    2016-11-01

    Full Text Available Objective: To assess the antimicrobial susceptibility pattern of ESKAPE pathogens from Neyshabur, Iran during 2013–2015. Methods: A total of 345 isolates including 62 Staphylococcus aureus (S. aureus, 38 Enterobacter spp. (including 14 Enterobacter agglomerans, 6 Enterobacter aerogenes and other 18 Enterobacter spp., 123 Enterococcus faecium, 78 Klebsiella pneumonia, 10 Pseudomonas aeruginosa and 34 Acinetobacter baumannii were isolated. The antimicrobial susceptibility pattern of isolates was conducted with Kirby Bauer method. Data were analyzed with SPSS 20.0 software using F- and t-tests. Results: Among S. aureus isolates, the highest resistance was observed against nalidixic acid (81.35% and cefixime (74.50%. Thirty-three (53.22% S. aureus isolates were cefoxitin resistant (methicillin-resistant S. aureus. The majority of Enterobacter species was resistant to amikacin (100.00% and cephalotin (66.60%. Most Enterococcus faecium isolates were resistant to nalidixic acid (89.43% and amikacin (83.33%, but vancomycin-resistant enterococci isolates were not detected. Moreover, among Klebsiella pneumonia, the highest resistance was observed to nalidixic acid (20.98% and cotrimoxazole (28.39%. Furthermore, all Pseudomonas aeruginosa isolates were resistant to cefotaxime (100.00% and majority to nitroforantoin (88.80%. Acinetobacter baumannii isolates showed the highest and the lowest resistance to cefotaxime (100.00% and cefixime (88.71%, respectively. Conclusions: The prevalence of ESKAPE pathogens from northeast region was low, but majority of them exhibited high rate of antibiotic resistance to common used antimicrobial agents.

  7. Analysis and Presentation of Cumulative Antimicrobial Susceptibility Test Data--The Influence of Different Parameters in a Routine Clinical Microbiology Laboratory.

    Science.gov (United States)

    Kohlmann, Rebekka; Gatermann, Sören G

    2016-01-01

    Many clinical microbiology laboratories report on cumulative antimicrobial susceptibility testing (cAST) data on a regular basis. Criteria for generation of cAST reports, however, are often obscure and inconsistent. Whereas the CLSI has published a guideline for analysis and presentation of cAST data, national guidelines directed at clinical microbiology laboratories are not available in Europe. Thus, we sought to describe the influence of different parameters in the process of cAST data analysis in the setting of a German routine clinical microbiology laboratory during 2 consecutive years. We developed various program scripts to assess the consequences ensuing from different algorithms for calculation of cumulative antibiograms from the data collected in our clinical microbiology laboratory in 2013 and 2014. One of the most pronounced effects was caused by exclusion of screening cultures for multi-drug resistant organisms which decreased the MRSA rate in some cases to one third. Dependent on the handling of duplicate isolates, i.e. isolates of the same species recovered from successive cultures on the same patient during the time period analyzed, we recorded differences in resistance rates of up to 5 percentage points for S. aureus, E. coli and K. pneumoniae and up to 10 percentage points for P. aeruginosa. Stratification by site of care and specimen type, testing of antimicrobials selectively on resistant isolates, change of interpretation rules and analysis at genus level instead of species level resulted in further changes of calculated antimicrobial resistance rates. The choice of parameters for cAST data analysis may have a substantial influence on calculated antimicrobial resistance rates. Consequently, comparability of cAST reports from different clinical microbiology laboratories may be limited. We suggest that laboratories communicate the strategy used for cAST data analysis as long as national guidelines for standardized cAST data analysis and reporting

  8. Genetic variability of glutamate-gated chloride channel genes in ivermectin-susceptible and -resistant strains of Cooperia oncophora.

    Science.gov (United States)

    Njue, A I; Prichard, R K

    2004-12-01

    The glutamate-gated chloride channels (GluCls) are members of the ligand-gated ion channel superfamily that are thought to be involved in the mode of action of ivermectin and mechanism of resistance. Using reverse-transcriptase PCR techniques, 2 full-length GluCl cDNAs, encoding GluClalpha3 and GluClbeta subunits, were cloned from Cooperia oncophora, a nematode parasite of cattle. The two sequences show a high degree of identity to similar subunits from other nematodes. The C. oncophora GluClalpha3 subunit is most closely related to the Haemonchus contortus GluClalpha3B subunit, while C. oncophora GluClbeta subunit shares high sequence identity with the H. contortus GluClbeta subunit. Using single-strand conformation polymorphism, the genetic variability of these two genes was analysed in an ivermectin-susceptible isolate and an ivermectin-resistant field isolate of C. oncophora. Statistical analysis suggested an association between the C. oncophora GluClalpha3 gene and ivermectin resistance. No such association was seen with the GluClbeta gene.

  9. Effect of strain rate and temperature on the susceptibility of 304 austenitic stainless steel to hydrogen embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    El Shawesh, F. [Petroleum Research Center, Tripoli (Libyan Arab Jamahiriya)

    1998-12-31

    Cathodic charging of notched 304 austenitic stainless steel specimens was carried out in aqueous solution of 1N H{sub 2}SO{sub 4}, containing 250 mg/l NaAsO{sub 2}, at room temperature and 70 {+-} 2 C while undergoing tensile straining over a wide range of crosshead speed (833 {micro}m/s, 83 {micro}m/s, 8.3 {micro}m/s, 833 nm/s, 83 nm/s and 9.8 nm/s). Test at room temperature 22 {+-} 2 C resulted in a marked reduction in the elongation to fracture ratio (Esol/Eair) by reducing the crosshead speed. However, little reduction was observed in the stress to fracture ratio ({sigma}sol/{sigma}air). Quasi cleavage and intergranular fractures where the predominant failure modes when tests were carried out at low crosshead speeds, The extent of these modes of fracture was observed to increase by reducing the crosshead speed. Cathodic charging of 304 austenitic stainless steel at 70 {+-} 2 C caused less reduction in the elongation to fracture ratio compared to the tests carried out at room temperature. Consistent with the room temperature test results, the reduction in the elongation to fracture ratio was found to increase with reduced crosshead speed. However, restoration in the elongation to fracture ratio was exhibited by 304 austenitic stainless steel specimens tested at the lowest crosshead speed (9.8 nm/s). These results are in good agreement with the finding that hydrogen embrittlement is temperature and strain dependent. Quasi cleavage fracture associated with the plastic deformation was the predominant failure mode exhibited by 304 austenitic stainless steel specimens tested at 70 {+-} 2 C at low crosshead speeds.

  10. Genotypic Resistance in Helicobacter pylori Strains Correlates with Susceptibility Test and Treatment Outcomes after Levofloxacin- and Clarithromycin-Based Therapies▿

    Science.gov (United States)

    Liou, Jyh-Ming; Chang, Chi-Yang; Sheng, Wang-Huei; Wang, Yu-Chi; Chen, Mei-Jyh; Lee, Yi-Chia; Hung, Hsu-Wei; Chian, Hung; Chang, San-Chun; Wu, Ming-Shiang; Lin, Jaw-Town

    2011-01-01

    The accuracy of genotypic resistance to levofloxacin (gyrA mutations) and its agreement with treatment outcomes after levofloxacin-based therapy have not been reported. We aimed to assess the correlation. Helicobacter pylori strains isolated from patients who received levofloxacin-based and clarithromycin-based triple therapies in a previous randomized trial were analyzed for point mutations in gyrA and 23S rRNA. PCR followed by direct sequencing was used to assess the gyrA and 23S rRNA mutations. An agar dilution test was used to determine the MICs of clarithromycin and levofloxacin. We found that the agreement between genotypic and phenotypic resistance to levofloxacin was best when the MIC breakpoint was >1 μg/ml (kappa coefficient, 0.754). The eradication rates in patients with and without gyrA mutations were 41.7% and 82.7%, respectively (P = 0.003). The agreement between genotypic and phenotypic resistance to clarithromycin was best when the MIC breakpoint was >2 μg/ml (kappa, 0.694). The eradication rates in patients with and without 23S rRNA mutations were 7.7% and 93.5%, respectively (P levofloxacin-based triple therapy and genotypic and phenotypic resistance were 0.244 and 0.190, respectively. In conclusion, gyrA and 23S rRNA mutations in H. pylori strains appeared to be better markers than phenotypic resistance in the prediction of treatment outcomes. The optimal breakpoints for levofloxacin and clarithromycin resistance appeared to be >1 μg/ml and >2 μg/ml, respectively. PMID:21189342

  11. Characterization and antimicrobial susceptibility of one antibiotic-sensitive and one multidrug-resistant Corynebacterium kroppenstedtii strain isolated from patients with granulomatous mastitis

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    I. Fernández-Natal

    2016-11-01

    Full Text Available Human infections associated with Corynebacterium kroppenstedtii are rarely reported, and this organism is usually described as antibiotic sensitive. Almost all published cases of C. kroppenstedtii infections have been associated with breast pathology in women and have been described in New Zealand, France, Canada, India and Japan. Here we describe the microbiologic characteristics of two strains isolated from two women diagnosed of granulomatous mastitis in Spain. One C. kroppenstedtii isolate was antibiotic sensitive while the other was multidrug resistant. Biochemical identification was possible using a wide battery of methods including API Coryne V2.0, API Strep, API NH, API NE, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA gene amplification and sequencing. Antimicrobial susceptibility to 28 antibiotics as determined by Etest showed one isolate being sensitive to benzylpenicillin, ciprofloxacin, moxifloxacin, gentamicin, vancomycin, clindamycin, tetracycline, linezolid and rifampin. The second isolate showed resistance to ciprofloxacin, moxifloxacin, clindamycin, tetracycline and rifampin. The multidrug-resistant isolate contained the erm(X, tet(W, cmx, aphA1-IAB, strAB and sul1 resistance genes known from the R plasmid pJA144188 of Corynebacterium resistens. These genes were absent in the genome of the antibiotic-sensitive isolate. This report confirms the tropism of this microorganism for women's breasts and presents the first description of a multidrug-resistant C. kroppenstedtii strain.

  12. In Vitro Activities of Daptomycin-, Vancomycin-, and Teicoplanin-Loaded Polymethylmethacrylate against Methicillin-Susceptible, Methicillin-Resistant, and Vancomycin-Intermediate Strains of Staphylococcus aureus▿

    Science.gov (United States)

    Chang, Yuhan; Chen, Wen-Chien; Hsieh, Pang-Hsin; Chen, Dave W.; Lee, Mel S.; Shih, Hsin-Nung; Ueng, Steve W. N.

    2011-01-01

    The objective of this study was to evaluate the antibacterial effects of polymethylmethacrylate (PMMA) bone cements loaded with daptomycin, vancomycin, and teicoplanin against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-intermediate Staphylococcus aureus (VISA) strains. Standardized cement specimens made from 40 g PMMA loaded with 1 g (low-dose), 4 g (middle-dose) or 8 g (high-dose) antibiotics were tested for elution characteristics and antibacterial activities. The patterns of release of antibiotics from the cement specimens were evaluated using in vitro broth elution assay with high-performance liquid chromatography. The activities of broth elution fluid against different Staphylococcus aureus strains (MSSA, MRSA, and VISA) were then determined. The antibacterial activities of all the tested antibiotics were maintained after being mixed with PMMA. The cements loaded with higher dosages of antibiotics showed longer elution periods. Regardless of the antibiotic loading dose, the teicoplanin-loaded cements showed better elution efficacy and provided longer inhibitory periods against MSSA, MRSA, and VISA than cements loaded with the same dose of vancomycin or daptomycin. Regarding the choice of antibiotics for cement loading in the treatment of Staphylococcus aureus infection, teicoplanin was superior in terms of antibacterial effects. PMID:21930872

  13. In vitro activities of daptomycin-, vancomycin-, and teicoplanin-loaded polymethylmethacrylate against methicillin-susceptible, methicillin-resistant, and vancomycin-intermediate strains of Staphylococcus aureus.

    Science.gov (United States)

    Chang, Yuhan; Chen, Wen-Chien; Hsieh, Pang-Hsin; Chen, Dave W; Lee, Mel S; Shih, Hsin-Nung; Ueng, Steve W N

    2011-12-01

    The objective of this study was to evaluate the antibacterial effects of polymethylmethacrylate (PMMA) bone cements loaded with daptomycin, vancomycin, and teicoplanin against methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-intermediate Staphylococcus aureus (VISA) strains. Standardized cement specimens made from 40 g PMMA loaded with 1 g (low-dose), 4 g (middle-dose) or 8 g (high-dose) antibiotics were tested for elution characteristics and antibacterial activities. The patterns of release of antibiotics from the cement specimens were evaluated using in vitro broth elution assay with high-performance liquid chromatography. The activities of broth elution fluid against different Staphylococcus aureus strains (MSSA, MRSA, and VISA) were then determined. The antibacterial activities of all the tested antibiotics were maintained after being mixed with PMMA. The cements loaded with higher dosages of antibiotics showed longer elution periods. Regardless of the antibiotic loading dose, the teicoplanin-loaded cements showed better elution efficacy and provided longer inhibitory periods against MSSA, MRSA, and VISA than cements loaded with the same dose of vancomycin or daptomycin. Regarding the choice of antibiotics for cement loading in the treatment of Staphylococcus aureus infection, teicoplanin was superior in terms of antibacterial effects.

  14. Susceptibility of Diaphorina citri (Hemiptera: Liviidae) and Its Parasitoid Tamarixia radiata (Hymenoptera: Eulophidae) to Entomopathogenic Fungi under Laboratory Conditions.

    Science.gov (United States)

    Ibarra-Cortés, K H; Guzmán-Franco, A W; González-Hernández, H; Ortega-Arenas, L D; Villanueva-Jiménez, J A; Robles-Bermúdez, A

    2018-02-01

    Diaphorina citri (Kuwayama) is a global pest of citrus that transmits the bacteria associated with the disease, Huanglongbing. Entomopathogenic fungi and the parasitoid Tamarixia radiata (Waterston) are important biological control agents of this pest and likely to interact in D. citri populations. As a basis for interaction studies, we determined the susceptibility of nymphs and adults of D. citri and adults of the parasitoid T. radiata to six fungal isolates from the species Beauveria bassiana s.l. (Bals.-Criv.) Vuill. (isolates B1 and B3), Metarhizium anisopliae s.s. (Metsch.) (Ma129 and Ma65) and Isaria fumosorosea Wize (I2 and Pae). We conducted experiments evaluating infection levels in all three insect groups following inoculation with a series of conidial concentrations (1 × 10 4 -1 × 10 8 conidia mL -1 ). Results showed that D. citri nymphs and T. radiata were more susceptible to fungal isolates than D. citri adults. Overall, B. bassiana and M. anisopliae isolates caused the greatest infection compared with I. fumosorosea isolates in all three groups of insects. Isolates B1 (B. bassiana) and Ma129 (M. anisopliae) infected a greater proportion of adults and nymphs of D. citri, respectively. Both isolates of B. bassiana caused greater infection in T. radiata compared with isolates of the other fungal species. We propose that isolates B1 and Ma129 are the strongest candidates for control of D. citri. Our results represent the first report of entomopathogenic fungi infecting T. radiata, and the basis for future studies to design a biological control programme that uses both agents more efficiently against D. citri populations.

  15. Crystal Structures of Penicillin-Binding Protein 2 From Penicillin-Susceptible And -Resistant Strains of Neisseria Gonorrhoeae Reveal An Unexpectedly Subtle Mechanism for Antibiotic Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Powell, A.J.; Tomberg, J.; Deacon, A.M.; Nicholas, R.A.; Davies, C.

    2009-05-21

    Penicillin-binding protein 2 (PBP2) from N. gonorrhoeae is the major molecular target for {beta}-lactam antibiotics used to treat gonococcal infections. PBP2 from penicillin-resistant strains of N. gonorrhoeae harbors an aspartate insertion after position 345 (Asp-345a) and 4-8 additional mutations, but how these alter the architecture of the protein is unknown. We have determined the crystal structure of PBP2 derived from the penicillin-susceptible strain FA19, which shows that the likely effect of Asp-345a is to alter a hydrogen-bonding network involving Asp-346 and the SXN triad at the active site. We have also solved the crystal structure of PBP2 derived from the penicillin-resistant strain FA6140 that contains four mutations near the C terminus of the protein. Although these mutations lower the second order rate of acylation for penicillin by 5-fold relative to wild type, comparison of the two structures shows only minor structural differences, with the positions of the conserved residues in the active site essentially the same in both. Kinetic analyses indicate that two mutations, P551S and F504L, are mainly responsible for the decrease in acylation rate. Melting curves show that the four mutations lower the thermal stability of the enzyme. Overall, these data suggest that the molecular mechanism underlying antibiotic resistance contributed by the four mutations is subtle and involves a small but measurable disordering of residues in the active site region that either restricts the binding of antibiotic or impedes conformational changes that are required for acylation by {beta}-lactam antibiotics.

  16. Susceptibilidad "in vitro" de cepas de Cryptococcus a 5 drogas antifungicas "In vitro" susceptibility of Cryptococcus strains to 5 antifungal drugs

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    A. J. Bava

    1989-10-01

    Full Text Available Se estudió la susceptibilidad "in vitro" de 24 cepas de 3 especies del género Cryptococcus a 5 drogas antifúngicas (anfotericina B, 5 fluorocitosina, ketoconazol, itraconazol y miconazol. Las mismas se agruparon según su especie, variedad y origen de aislamiento. Para determinar la concentración inhibitoria mínima (C.I.M. de cada droga se empleó el método de dilución en agar con el medio básico nitrogenado para levaduras, adicionado de glucosa. Se obtuvo además la media geométrica de estos valores para cada grupo y se comparó cada uno de ellos. Los resultados obtenidos fueron homogéneos con la sola excepción de las cepas de Cryptococcus sp (no neoformans, en las cuales se detectaron elevados valores de C.I.M. para la 5 fluorocitosina.A comparative study of the "in vitro" susceptibility of 24 Cryptococcus strains to 5 antifungal drugs (amphotericin B, 5 fluorocytosine, miconazole, itraconazole and ketoconazole, was carried out. These strains were grouped according to species, varieties and isolation's origins. The minimum inhibitory concentration (M.I.C. was determinated by the agar dilution technique in yeast nitrogen base agar with dextrose. The mean geometrical of the M.I.C. values of each group was compared with the others. The results obtained were homogeneous with the only exception of the "non neoformans" strains, in which, higher M.I.C. to 5 fluorocytosine values were detected.

  17. Susceptibility of Algerian pepper cultivars (Capsicum annuum L) to ...

    African Journals Online (AJOL)

    Utilisateur

    2015-11-04

    Nov 4, 2015 ... Susceptibility of Algerian pepper cultivars (Capsicum annuum L) to Phytophthora capsici strains from different geographic areas. Benabdelkader Messaouda, Guechi Abdelhadi and Mézaache-Aichour Samia*. Laboratory of Applied Microbiology (phytopathology team), Department of Microbiology, Faculty ...

  18. Statins demonstrate a broad anti-cytomegalovirus activity in vitro in ganciclovir-susceptible and resistant strains.

    Science.gov (United States)

    Ponroy, Nicolas; Taveira, Aline; Mueller, Nicolas J; Millard, Anne-Laure

    2015-01-01

    Vasculoprotective and cholesterol-lowering properties are hallmarks of statins. Recently, statins have been found to exhibit antiviral activity. Little is known about the potential of statins against human cytomegalovirus (HCMV), a risk factor in the pathogenesis of atherosclerosis. In this study, the in vitro anti-CMV activity of four statins (atorva-, fluva-, prava-, and simvastatin) was explored in human aortic endothelial cells (HAEC) and fibroblasts. All statins dose-dependently reduced HCMV titers in both cell types. Whereas atorva-, fluva-, and simvastatin showed comparable EC50 and EC90 within a low micromolar range in HAEC, pravastatin exhibited only limited effects. In metabolite rescue experiments, mevalonate almost completely abrogated the anti-CMV activity of all statins, whereas cholesterol failed to counteract the effects. Geranylgeranyl-pyrophosphate partially reversed the anti-CMV activity of most statins, suggesting an involvement of the non-sterol isoprenoid arm of the mevalonate pathway as the mode-of-action. The accumulation of immediate early viral antigens was blocked after 1 dpi onwards, and early and late antigen expression was completely abolished in HAEC. The antiviral activity of statins was comparable to ganciclovir and was retained in a ganciclovir-resistant HCMV strain. These findings provide new insight into the beneficial effects of statins, adding antiviral activity against HCMV to their list of pleïotropic properties, and support further clinical investigations on combined therapy for the management of active HCMV disease. © 2014 Wiley Periodicals, Inc.

  19. Genetic Basis of Cry1F-Resistance in a Laboratory Selected Asian Corn Borer Strain and Its Cross-Resistance to Other Bacillus thuringiensis Toxins.

    Directory of Open Access Journals (Sweden)

    Yueqin Wang

    Full Text Available The Asian corn borer (ACB, Ostrinia furnacalis (Guenée (Lepidoptera: Crambidae, is the most destructive insect pest of corn in China. Susceptibility to the Cry1F toxin derived from Bacillus thuringiensis has been demonstrated for ACB, suggesting the potential for Cry1F inclusion as part of an insect pest management program. Insects can develop resistance to Cry toxins, which threatens the development and use of Bt formulations and Bt crops in the field. To determine possible resistance mechanisms to Cry1F, a Cry1F-resistant colony of ACB (ACB-FR that exhibited more than 1700-fold resistance was established through selection experiments after 49 generations of selection under laboratory conditions. The ACB-FR strain showed moderate cross-resistance to Cry1Ab and Cry1Ac of 22.8- and 26.9-fold, respectively, marginally cross-resistance to Cry1Ah (3.7-fold, and no cross-resistance to Cry1Ie (0.6-fold. The bioassay responses of progeny from reciprocal F1 crosses to different Cry1 toxin concentrations indicated that the resistance trait to Cry1Ab, Cry1Ac and Cry1F has autosomal inheritance with no maternal effect or sex linked. The effective dominance (h of F1 offspring was calculated at different concentrations of Cry1F, showing that h decreased as concentration of Cry1F increased. Finally, the analysis of actual and expected mortality of the progeny from a backcross (F1 × resistant strain indicated that the inheritance of the resistance to Cry1F in ACB-FR was due to more than one locus. The present study provides an understanding of the genetic basis of Cry1F resistance in ACB-FR and also shows that pyramiding Cry1F with Cry1Ah or Cry1Ie could be used as a strategy to delay the development of ACB resistance to Bt proteins.

  20. Toxicity and Metabolism of Zeta-Cypermethrin in Field-Collected and Laboratory Strains of the Neotropical Predator Chrysoperla externa Hagen (Neuroptera: Chrysopidae).

    Science.gov (United States)

    Haramboure, M; Smagghe, G; Niu, J; Christiaens, O; Spanoghe, P; Alzogaray, R A

    2017-06-01

    Resistance to pesticides has been studied in several insect pests, but information on the natural enemies of pests-including the Neotropical predator Chrysoperla externa Hagen (Neuroptera: Chrysopidae), a major biological control agent in South America-is lacking. We report here a comparative study between a field-collected strain of C. externa subjected to monthly sprayings of pyrethroids and neonicotinoids and a laboratory strain without exposure to pesticides. The tolerance of both strains against zeta-cypermethrin was similar, and addition of the synergist piperonyl butoxide increased the toxicity by 30% in both strains. Gas-chromatography analyses and mixed-function-oxidase measurements indicated similar values in both strains and also confirmed the key role of oxidative metabolism in this species. Because C. externa has maintained a tolerance to zeta-cypermethrin without previous pesticide exposure, this species could potentially be mass-reared and released in fields in the presence of pesticide pressure.

  1. Colistin Dosage without Loading Dose Is Efficacious when Treating Carbapenem-Resistant Acinetobacter baumannii Ventilator-Associated Pneumonia Caused by Strains with High Susceptibility to Colistin.

    Science.gov (United States)

    Álvarez-Marín, Rocío; López-Rojas, Rafael; Márquez, Juan Antonio; Gómez, María José; Molina, José; Cisneros, José Miguel; Ortiz-Leyba, Carlos; Aznar, Javier; Garnacho-Montero, José; Pachón, Jerónimo

    2016-01-01

    This study aims to analyze the mortality and the length of ICU stay (LOS) of A. baumannii VAP compared to respiratory colonization in patients with mechanical ventilation (MV). A prospective cohort study was performed in an ICU of adult patients (February 2010-June 2011). One hundred patients on MV with A. baumannii in lower respiratory airways were recruited, and classified as VAP or airways colonization according to CPIS criteria, with a punctuation ≥6. LOS, 30-days mortality, A. baumannii bacteremia, and clinical features including antibiotic therapy were recorded. Multivariate analysis (linear and Cox regression) and survival analysis (Kaplan-Meier curves) were performed. Fifty-seven VAP and 43 colonized A. baumannii patients were analyzed. Among the A. baumannii strains, 99% were non-susceptible to carbapenems and the MIC90 of colistin was 0.12 mg/l. Therapy was appropriate in 94.6% of VAP patients, most of them with colistin 6 MIU/day, although in 13 (23.6%) cases colistin was started 48 hours after the onset of VAP. Mortality was similar in both groups (VAP 24.6% vs. colonized 27.9%, p = 0.7). Bacteremia and acute kidney insufficiency were associated with decreased survival (p = 0.02 and p = 0.04, respectively) in VAP patients. LOS was 21.5 (11.5-42.75) vs. 9 (6-22) days for VAP and colonized patients (p = 0.004). VAP (p = 0.003) and age (p = 0.01) were independently related to a longer LOS. Multidrug-resistant A. baumannii VAP treated with colistin does not have a different mortality compared to lower airways colonization, among patients on mechanical-ventilation, in a setting of high susceptibility to colistin of A. baumannii.

  2. Multilocus Variable-Number Tandem-Repeat Analysis, Pulsed-Field Gel Electrophoresis, and Antimicrobial Susceptibility Patterns in Discrimination of Sporadic and Outbreak-Related Strains of Yersinia enterocolitica

    Directory of Open Access Journals (Sweden)

    Skurnik Mikael

    2011-02-01

    Full Text Available Abstract Background We assessed the potential of multilocus variable-number tandem-repeat analysis (MLVA, pulsed-field gel electrophoresis (PFGE, and antimicrobial susceptibility testing for discriminating 104 sporadic and outbreak-related Yersinia enterocolitica (YE bio/serotype 3-4/O:3 and 2/O:9 isolates. MLVA using six VNTR markers was performed in two separate multiplex PCRs, and the fluorescently labeled PCR products were accurately sized on an automated DNA sequencer. Results MLVA discriminated 82 sporadic YE 3-4/O:3 and 2/O:9 strains into 77 types, whereas PFGE with the restriction enzyme NotI discriminated the strains into 23 different PFGE pulsotypes. The discriminatory index for a sporadic strain was 0.862 for PFGE and 0.999 for MLVA. MLVA confirmed that a foodborne outbreak in the city of Kotka, Finland in 2003 had been caused by a multiresistant YE 4/O:3 strain that was distinctly different from those of epidemiologically unrelated strains with an identical PFGE pulsotype. The multiresistance of Y. enterocolitica strains (19% of the sporadic strains correlated significantly (p = 0.002 with travel abroad. All of the multiresistant Y. enterocolitica strains belonged to four PFGE pulsotypes that did not contain any susceptible strains. Resistance to nalidixic acid was related to changes in codons 83 or 87 that stemmed from mutations in the gyrA gene. The conjugation experiments demonstrated that resistance to CHL, STR, and SUL was carried by a conjugative plasmid. Conclusions MLVA using six loci had better discriminatory power than PFGE with the NotI enzyme. MLVA was also a less labor-intensive method than PFGE and the results were easier to analyze. The conjugation experiments demonstrated that a resistance plasmid can easily be transferred between Y. enterocolitica strains. Antimicrobial multiresistance of Y. enterocolitica strains was significantly associated with travel abroad.

  3. Efficacy of four commercially available heartworm preventive products against the JYD-34 laboratory strain of Dirofilaria immitis.

    Science.gov (United States)

    Blagburn, Byron L; Arther, Robert G; Dillon, Allen R; Butler, Jamie M; Bowles, Joy V; von Simson, Cristiano; Zolynas, Robert

    2016-04-05

    Heartworm disease in dogs can be severe and life threatening. Resistance to available heartworm preventives was considered among potential causes of increased reports of failed heartworm prevention in dogs. The objective of the present study was to compare the efficacy of four commercially available heartworm disease preventives against the JYD-34 strain of D. immitis. Forty laboratory-reared dogs approximately 6 months old were used. Each dog was infected with fifty, third-stage heartworm larvae on study day (SD) -30. On SD-1, the dogs were randomized to five groups of eight dogs each. On SD-0, dogs in groups 1-4 were treated as follows: Group 1: ivermectin/pyrantel pamoate chewable tablets; Group 2: milbemycin oxime/spinosad tablets; Group 3: selamectin topical solution; and Group 4: imidacloprid/moxidectin topical solution. Dogs in Group 5 were not treated and served as controls. The dogs were treated according to their current body weights and labelled dose banding for each product. Groups 1, 2, and 3 were retreated with their respective products and current body weights on SD 31 and 60. On SDs 124-126 the dogs were euthanized and necropsied for recovery of adult heartworms. Adult heartworms were recovered at necropsy from each of the dogs in the control group (13-32 worms/dog, geometric mean (GM) = 18.4 worms/dog). Adult heartworms and/or worm fragments were also recovered from each of the dogs treated with ivermectin/pyrantel pamoate, milbemycin oxime/spinosad or selamectin. Geometric means of worms recovered from dogs in each of these groups were 13.1, 8.8, and 13.1, resulting in efficacies compared to controls of 29.0, 52.2, and 28.8 %, respectively. All dogs in Group 4 (imidacloprid/moxidectin) were free of adult heartworms (100 % efficacy). The combination of imidacloprid/moxidectin was 100 % effective in this study in preventing development of JYD-34 laboratory strain of D. immitis in dogs following a single treatment, while three monthlytreatments of

  4. Thermal limits of wild and laboratory strains of two African malaria vector species, Anopheles arabiensis and Anopheles funestus

    Directory of Open Access Journals (Sweden)

    Lyons Candice L

    2012-07-01

    Full Text Available Abstract Background Malaria affects large parts of the developing world and is responsible for almost 800,000 deaths annually. As climates change, concerns have arisen as to how this vector-borne disease will be impacted by changing rainfall patterns and warming temperatures. Despite the importance and controversy surrounding the impact of climate change on the potential spread of this disease, little information exists on the tolerances of several of the vector species themselves. Methods Using a ramping protocol (to assess critical thermal limits - CT and plunge protocol (to assess lethal temperature limits - LT information on the thermal tolerance of two of Africa’s important malaria vectors, Anopheles arabiensis and Anopheles funestus was collected. The effects of age, thermal acclimation treatment, sex and strain (laboratory versus wild adults were investigated for CT determinations for each species. The effects of age and sex for adults and life stage (larvae, pupae, adults were investigated for LT determinations. Results In both species, females are more tolerant to low and high temperatures than males; larvae and pupae have higher upper lethal limits than do adults. Thermal acclimation of adults has large effects in some instances but small effects in others. Younger adults tend to be more tolerant of low or high temperatures than older age groups. Long-standing laboratory colonies are sufficiently similar in thermal tolerance to field-collected animals to provide reasonable surrogates when making inferences about wild population responses. Differences between these two vectors in their thermal tolerances, especially in larvae and pupae, are plausibly a consequence of different habitat utilization. Conclusions Limited plasticity is characteristic of the adults of these vector species relative to others examined to date, suggesting limited scope for within-generation change in thermal tolerance. These findings and the greater tolerance

  5. Trends of Mycobacterium bovis Isolation and First-Line Anti-tuberculosis Drug Susceptibility Profile: A Fifteen-Year Laboratory-Based Surveillance.

    Directory of Open Access Journals (Sweden)

    Miriam Bobadilla-del Valle

    2015-09-01

    Full Text Available Mycobacterium tuberculosis causes the majority of tuberculosis (TB cases in humans; however, in developing countries, human TB caused by M. bovis may be frequent but undetected. Human TB caused by M. bovis is considered a zoonosis; transmission is mainly through consumption of unpasteurized dairy products, and it is less frequently attributed to animal-to-human or human-to-human contact. We describe the trends of M. bovis isolation from human samples and first-line drug susceptibility during a 15-year period in a referral laboratory located in a tertiary care hospital in Mexico City.Data on mycobacterial isolates from human clinical samples were retrieved from the laboratory's database for the 2000-2014 period. Susceptibility to first-line drugs: rifampin, isoniazid, streptomycin (STR and ethambutol was determined. We identified 1,165 isolates, 73.7% were M. tuberculosis and 26.2%, M. bovis. Among pulmonary samples, 16.6% were M. bovis. The proportion of M. bovis isolates significantly increased from 7.8% in 2000 to 28.4% in 2014 (X(2trend, p<0.001. Primary STR resistance was higher among M. bovis compared with M. tuberculosis isolates (10.9% vs.3.4%, p<0.001. Secondary multidrug resistance (MDR rates were 38.5% and 34.4% for M. bovis and M. tuberculosis, respectively (p = 0.637. A rising trend of primary STR monoresistance was observed for both species (3.4% in 2000-2004 vs. 7.6% in 2010-2014; p = 0.02.There is a high prevalence and a rising trend of M. bovis isolates in our region. The proportion of pulmonary M. bovis isolates is higher than in previous reports. Additionally, we report high rates of primary anti-tuberculosis resistance and secondary MDR in both M. tuberculosis and M. bovis. This is one of the largest reports on drug susceptibility of M. bovis from human samples and shows a significant proportion of first-line anti-tuberculosis drug resistance.

  6. Molecular analysis and susceptibility patterns of methicillin-resistant Staphylococcus aureus strains causing community- and health care-associated infections in the northern region of Palestine.

    Science.gov (United States)

    Adwan, Kamel; Jarrar, Naser; Abu-Hijleh, Awni; Adwan, Ghaleb; Awwad, Elena; Salameh, Yousef

    2013-03-01

    Community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a major global problem. This study attempted to investigate the prevalence of nasal carriage of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) strains among 360 healthy university students at An-Najah National University, Palestine. For the purpose of comparing the staphylococcal cassette chromosome methicillin resistant determinant (SCCmec) type of MRSA, 46 clinical MRSA isolates were also included in this study. Susceptibility testing was performed by the disc diffusion method. The genetic association of MRSA isolates was investigated by SCCmec typing. A selected number of isolates were also used to amplify and sequence mecA. Nasal carriage of S aureus was found in 86 of 360 students (24%). MRSA accounted for 9% of S aureus isolates. All 86 strains of S aureus were sensitive to vancomycin. Resistance to penicillin G, amoxicillin/clavulanic acid, ciprofloxacin, erythromycin, and clindamycin was found in 98%, 93%, 33%, 23%, and 12% of the isolates, respectively. Resistance rates of the MRSA isolates were as follows: 100% resistant to penicillin G and amoxicillin/clavulanic acid, 96% to ethromycin, 52% to clindamycin, and 48% to ciprofloxacin. No vancomycin-resistant isolates were identified. In our study, nearly half (52%) of the MRSA isolates belonged to SCCmec types IVa and V. However, SCCmec types II and III are represented by 48%, whereas SCCmec type I was completely absent. The findings of this study indicate the existence of SCCmec type IVa in both student nasal carriers and health care settings. This emphasizes the need for implementation of a revised set of control measures in both settings. Moreover, the rational prescription of appropriate antibiotics should also be considered. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  7. Antimicrobial susceptibility testing of Neisseria gonorrhoeae isolates in Pakistan by Etest compared to Calibrated Dichotomous Sensitivity and Clinical Laboratory Standards Institute disc diffusion techniques.

    Science.gov (United States)

    Mal, Pushpa Bhawan; Jabeen, Kauser; Farooqi, Joveria; Unemo, Magnus; Khan, Erum

    2016-10-10

    Accurate detection of Neisseria gonorrhoeae antimicrobial resistance is essential for appropriate management and prevention of spread of infection in the community. In this study Calibrated Dichotomous Sensitivity (CDS) and Clinical Laboratory Standards Institute (CLSI) disc diffusion methods were compared with minimum inhibitory concentration (MIC) by Etest in Neisseria gonorrhoeae isolates from Karachi, Pakistan. CDS and CLSI disc diffusion techniques, and Etest for ceftriaxone, penicillin G, spectinomycin and ciprofloxacin against 100 isolates from years 2012-2014 were performed. Due to lack of CLSI breakpoints for azithromycin, it was interpreted using cut-offs from British Society of Antimicrobial Chemotherapy (BSAC). Due to lack of low concentration tetracycline discs, tetracycline was tested with CLSI disc diffusion and Etest only. Comparisons were based on the identified susceptibility, intermediate susceptibility and resistance (SIR) categories using the different methods. Complete percent agreement was percentage agreement achieved when test and reference method had identical SIR-category. Essential percent agreement was percentage agreement when minor discrepancies were disregarded. There was 100 % and 99 % overall essential agreement and 50 % versus 23 % overall complete agreement by CDS and CLSI methods, respectively, with MICs for all tested antibiotics. Using either method, there was 100 % complete agreement for ceftriaxone and spectinomycin. There was 90 % versus 86 % complete agreement for ciprofloxacin, and 60 % and 75 % for penicillin using CDS and CLSI method, respectively. Essential agreement of 99 % and complete agreement of 62 % was found for tetracycline with CLSI method. There was 100 % essential and complete agreement by CDS, BSAC and Etest for azithromycin. No major errors with regard to identified SIR-categories were found for penicillin, ciprofloxacin, ceftriaxone and spectinomycin using CLSI and CDS methods. All isolates

  8. Laboratory selection for spirodiclofen resistance and cross ...

    African Journals Online (AJOL)

    Selection for spirodiclofen resistance was done in the laboratory with a susceptible strain of the citrus red mite, Panonychus citri (McGregor). Successive selections for spirodiclofen resistance through 42 generations resulted in a high level of resistance and the resistance ratio at LC50 was 103 compared with that of the ...

  9. Laboratory selection for spirodiclofen resistance and cross ...

    African Journals Online (AJOL)

    Administrator

    2011-04-25

    Apr 25, 2011 ... Selection for spirodiclofen resistance was done in the laboratory with a susceptible strain of the citrus red mite, Panonychus citri (McGregor). Successive selections for spirodiclofen resistance through 42 generations resulted in a high level of resistance and the resistance ratio at LC50 was 103 compared.

  10. Incidence of oral indigenous bacteria in causative strains isolated from blood cultures in 759 laboratory-confirmed cases of bacteremia

    Directory of Open Access Journals (Sweden)

    Shinya Yura

    2012-05-01

    Full Text Available Background: The incidence of oral indigenous bacteria in cases of bacteremia has been reported in only a few studies. We investigated the annual incidence of oral indigenous bacteria isolated in blood cultures from patients with bacteremia and call into consideration the impact of oral health measures implemented at our facility. Methods: In the period from 2001 to 2006, 759 laboratory-confirmed cases of bacteremia were reported and subsequently analyzed in this study. The incidences of the causative strain and oral indigenous bacteria in blood cultures were studied by year Results: In 759 cases of bacteremia, oral streptococci were noted in 14 (1.8%, and anaerobic bacteria were noted in 9 (1.2%. The population of microorganisms did not change significantly during the study period. Conclusions: In a previous report, oral streptococci accounted for 3.8% of those under investigation. In this study, the incidence of oral streptococci was significantly low, 1.8% specifically. A focus on oral health care at our hospital may account for a reduced incidence of oral streptococci bacteremia.

  11. External Quality Assurance System (EQAS) of the WHO Global Salmonella Surveillance and Laboratory Support Project (Global Salm-Surv)

    DEFF Research Database (Denmark)

    Petersen, A.; Aarestrup, Frank Møller; Wong, S.

    laboratories in 35 countries participated. For serotyping, 76% of the results were correct. For susceptibility testing, 92% of the results for the eight Salmonella strains were in agreement with the expected results. However, 28% of the performed tests with the E. coli ATCC 25922 reference strain were out......To assure the quality of methods for serotyping and antimicrobial susceptibility testing among laboratories in WHO Global Salm-Surv, an international collaborative study on serotyping and antimicrobial susceptibility testing of eight Salmonella enterica strains was performed. A total of 44...

  12. In Vitro Antibiotic Susceptibilities of Francisella tularensis Determined by Broth Microdilution following CLSI Methods.

    Science.gov (United States)

    Heine, Henry S; Miller, Lynda; Halasohoris, Stephanie; Purcell, Bret K

    2017-09-01

    In vitro susceptibilities for 47 antibiotics were determined in 30 genetic diverse strains of Francisella tularensis by the broth microdilution method following Clinical and Laboratory Standards Institute (CLSI) methods. The F. tularensis strains demonstrated susceptibility to aminoglycosides, fluoroquinolones, and tetracyclines. There was a distinct difference in macrolide susceptibilities between A and B type strains, as has been noted previously. The establishment and comparison of antibiotic susceptibilities of a diverse but specific set of F. tularensis strains by standardized methods and the establishment of population ranges and MIC50/90 values provide reference information for assessing new antibiotic agents and a baseline to monitor any future emergence of resistance, whether natural or intentional. Copyright © 2017 American Society for Microbiology.

  13. Occurrence of 3 Bordetella species during an outbreak of cough illness in Ohio: epidemiology, clinical features, laboratory findings and antimicrobial susceptibility.

    Science.gov (United States)

    Spicer, Kevin B; Salamon, Doug; Cummins, Carol; Leber, Amy; Rodgers, Loren E; Marcon, Mario J

    2014-07-01

    An increase in laboratory diagnosis of pertussis was noted in central Ohio during 2010. Diagnosis was made using a polymerase chain reaction assay targeting the multicopy insertion sequence IS481, which is found in both Bordetella pertussis (Bp) and Bordetella holmesii (Bh). An increase in specimens testing positive for Bordetella parapertussis (Bpp) using insertion sequence IS1001 was also noted. Nasopharyngeal swab specimens submitted April 1, 2010, to March 31, 2011, were tested using a multiplex polymerase chain reaction assay for Bp/Bh (IS481) and Bpp followed by singleplex assays for Bp and Bh. A subgroup of specimens was also cultured for Bordetella species, and antimicrobial susceptibility testing was performed on recovered organisms. Demographic and clinical features were compared for patients with Bp, Bh and Bpp. Of 520 IS481-positive specimens, 214 (41.1%) were positive for Bp, 79 (15.2%) were positive for Bh and 5 (1.0%) were positive for both Bp and Bh; 222 (42.7%) were negative for both targets. An additional 220 specimens were positive for Bpp. Among a sample of 155 IS481-positive specimens, 40, 15 and 0 were culture positive for Bp, Bh and Bpp, respectively. Among a sample of 55 BparaIS1001-positive (Bpp) specimens, 22, 0 and 0 were culture positive for Bpp, Bp and Bh, respectively. All Bordetella species were susceptible to macrolide antibiotics. Patients with Bh were older than patients with Bp, who were older than those positive for Bpp (mean ages: 12.0, 8.0 and 4.2 years, respectively; P Bordetella species), but did not differ statistically among the groups (χ = 5.1, P = 0.17). All 3 Bordetella species, Bp, Bh and Bpp, were detected during on outbreak of pertussis-like cough illness. There were noted differences in age and seasonality, but clinical features at the time of presentation did not allow clear differentiation of these infections. All Bordetella species recovered from culture and tested were susceptible in vitro to macrolide

  14. Antibiotic Susceptibility of Potentially Probiotic Vaginal Lactobacilli

    Directory of Open Access Journals (Sweden)

    Virginia Ocaña

    2006-01-01

    Full Text Available Objective. To study the antimicrobial susceptibility of six vaginal probiotic lactobacilli. Methods. The disc diffusion method in Müeller Hinton, LAPTg and MRS agars by the NCCLS (National Committee for Clinical Laboratory Standards procedure was performed. Due to the absence of a Lactobacillus reference strains, the results were compared to those of Staphylococcus aureus ATCC29213. Minimal Inhibitory Concentration (MIC with 21 different antibiotics in LAPTg agar and broth was also determined. Results. LAPTg and MRS agars are suitable media to study antimicrobial susceptibility of lactobacilli. However, the NCCLS procedure needs to be standardized for this genus. The MICs have shown that all Lactobacillus strains grew at concentrations above 10 μg/mL of chloramphenicol, aztreonam, norfloxacin, ciprofloxacin, ceftazidime, ceftriaxone, streptomycin and kanamycin. Four lactobacilli were sensitive to 1 μg/mL vancomycin and all of them were resistant to 1000 μg/mL of metronidazole. Sensitivity to other antibiotics depended on each particular strain. Conclusions. The NCCLS method needs to be standardized in an appropriate medium to determine the antimicrobial susceptibility of Lactobacillus. Vaginal probiotic lactobacilli do not display uniform susceptibility to antibiotics. Resistance to high concentrations of metronidazole suggests that lactobacilli could be simultaneously used with a bacterial vaginosis treatment to restore the vaginal normal flora.

  15. Antibiotic Susceptibility of Potentially Probiotic Vaginal Lactobacilli

    Science.gov (United States)

    Ocaña, Virginia; Silva, Clara; Nader-Macías, María Elena

    2006-01-01

    Objective. To study the antimicrobial susceptibility of six vaginal probiotic lactobacilli. Methods. The disc diffusion method in Müeller Hinton, LAPTg and MRS agars by the NCCLS (National Committee for Clinical Laboratory Standards) procedure was performed. Due to the absence of a Lactobacillus reference strains, the results were compared to those of Staphylococcus aureus ATCC29213. Minimal Inhibitory Concentration (MIC) with 21 different antibiotics in LAPTg agar and broth was also determined. Results. LAPTg and MRS agars are suitable media to study antimicrobial susceptibility of lactobacilli. However, the NCCLS procedure needs to be standardized for this genus. The MICs have shown that all Lactobacillus strains grew at concentrations above 10 μg/mL of chloramphenicol, aztreonam, norfloxacin, ciprofloxacin, ceftazidime, ceftriaxone, streptomycin and kanamycin. Four lactobacilli were sensitive to 1 μg/mL vancomycin and all of them were resistant to 1000 μg/mL of metronidazole. Sensitivity to other antibiotics depended on each particular strain. Conclusions. The NCCLS method needs to be standardized in an appropriate medium to determine the antimicrobial susceptibility of Lactobacillus. Vaginal probiotic lactobacilli do not display uniform susceptibility to antibiotics. Resistance to high concentrations of metronidazole suggests that lactobacilli could be simultaneously used with a bacterial vaginosis treatment to restore the vaginal normal flora. PMID:17485797

  16. Molecular typing of methicillin-resistant Staphylococcus aureus strains by PCR-RFLP of SPA gene: A reference laboratory perspective

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    Mehndiratta P

    2009-01-01

    Full Text Available Purpose: To characterize methicillin-resistant Staphylococcus aureus (MRSA strains by molecular typing based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP of spa gene and to assess the utility of spa genotyping over bacteriophage typing in the discrimination of the strains. Materials and Methods: Studies were undertaken on 125 MRSA strains representing the most predominant phage types and the non phage typeable strains. Strains were typed by bacteriophage typing and PCR-RFLP of spa gene. DNA sequence analysis of the amplified spa gene fragment of the representative RFLP patterns was performed using standard protocols. Results: All the strains resistant to oxacillin were found to contain mec A gene. Fifty-two per cent of these strains were typeable by the international basic set of 23 phages. Five different PCR-RFLP patterns were observed among 125 MRSA strains. Non phage typeable strains were differentiated into four PCR-RFLP patterns. Sequencing of the spa gene from the representative strains of each RFLP pattern confirmed the length of these restriction fragments due to variation in the 24 bp and the 174 bp tandem repeats. It also revealed the presence of three new spa repeat patterns. Conclusion: The study demonstrates the importance of spa genotyping in the discrimination of MRSA strains, which were otherwise indistinguishable by bacteriophage typing. spa genotyping allowed differentiation of strains within a particular phage type. Nucleotide sequencing of isolates of different PCR-RFLP patterns indicated a correlation between the RFLP patterns of a variable number of tandem repeats and the phage type. The study provides valuable information on the epidemiological characterization of MRSA strains.

  17. Update: potential exposures to attenuated vaccine strain Brucella abortus RB51 during a laboratory proficiency test--United States and Canada, 2007.

    Science.gov (United States)

    2008-01-18

    In November 2007, New York State Department of Health (NYSDOH) officials notified CDC of potential exposures to attenuated vaccine strain Brucella abortus RB51 (RB51) in multiple clinical laboratories that participated in a Laboratory Preparedness Survey (LPS) proficiency test. NYSDOH conducted a survey of participating laboratories and identified 17 laboratories that reported handling the RB51 sample in a manner placing lab workers at potential risk for exposure. Subsequently, CDC recommended that public health officials conduct a review of biosafety practices at all LPS-participating laboratories to identify any additional RB51 exposures. This report summarizes the results of investigations in 36 states, two cities, one county, and the District of Columbia. As of January 14, 2008, follow-up by public health officials with LPS-participating laboratories throughout the United States identified a total of 916 laboratory workers in 254 laboratories with potential RB51 exposure. The results highlight the need for routine adherence to recommended biosafety practices when working with infectious organisms, particularly during widespread infectious-disease events, including bioterrorism attacks.

  18. [Resistant phenotypes of Escherichia coli strains responsible for urinary tract infection in the laboratory of the University Hospital Joseph Raseta Befelatanana, Antananarivo].

    Science.gov (United States)

    Rakotovao-Ravahatra, Zafindrasoa Domoina; Randriatsarafara, Fidiniaina Mamy; Rasoanandrasana, Saïda; Raverohanta, Léa; Rakotovao, Andriamiadana Luc

    2017-01-01

    Urinary tract infection caused by Escherichia coli frequently occurs in the hospital environment. This study aims to describe resistant phenotypes of Escherichia coli strains to monitor their occurrence. We conducted a descriptive retrospective study of 102 Escherchia coli strains responsible for urinary tract infection in the laboratory of the University Hospital Joseph Raseta Befelatanana, Antananarivo from January 2014 to October 2016. Beta-lactam antibiotic resistance screening identified high-level penicillinases 50% (n=51), Escherichia coli producing extended-spectrum beta-lactamases (ESBLs) 22.5% (n=23), high-level cephalosporinases 14.7% (n=15), penicillinases low level 5.9% (n=6), wild type strains 5.9% (n=6) and a strain ofEscherichia coli emerging strain high-level resistance. Aminoglycosides resistance was identified in 58 (56.9%) wild type phenotype, 29 (28.4%) strains sensitive to amikacin and 15 (14.7%) resistant to all aminoglycosides. Fluoroquinolones resistance was identified in 52 (51%) wild type strains, 9 (8.8%) strains sensitive to ciprofloxacin and 41 (40.2%) resistant to all fluoroquinolones. Women (25, 7%) (p= 0.25, NS), patients more than 60 years (38.7%) (p=0.02), patients hospitalized in the Department of Nephrology (53.8%) (p=0.04), with urinary disorder and kidney disease (29, 7%) (p= 0.2, NS) were the most affected by E-ESBL. Based on high multidrug resistance in Escherichia coli strains guidelines for the empirical treatment of urinary tract infections need to be revised.

  19. Influence of penicillin/amoxicillin non-susceptibility on the activity of third-generation cephalosporins against Streptococcus pneumoniae.

    Science.gov (United States)

    Fenoll, A; Giménez, M J; Robledo, O; Aguilar, L; Tarragó, D; Granizo, J J; Martín-Herrero, J E

    2008-01-01

    To study the influence of penicillin/amoxicillin non-susceptibility on the activity of third-generation cephalosporins, 430 consecutive penicillin non-susceptible Streptococcus pneumoniae 2007 isolates received in the Spanish Reference Pneumococcal Laboratory were tested. For comparative purposes, 625 penicillin-susceptible 2007 isolates were also tested. Susceptibility was determined by agar dilution using Mueller-Hinton agar supplemented with 5% sheep blood. Penicillin-susceptible strains were susceptible to amoxicillin, cefotaxime and ceftriaxone, 99.8% to cefpodoxime and 99.5% to cefdinir, and were inhibited by 0.12 microg/ml of cefditoren and 4 microg/ml of cefixime. Penicillin-intermediate strains were susceptible to cefotaxime and ceftriaxone, with <50% susceptibility to cefdinir and cefpodoxime. The MIC(50) and MIC(90) values of cefditoren were 0.25 microg/ml and 0.5 microg/ml, respectively, whereas cefixime exhibited only marginal activity (MIC(90)=16 microg/ml). Penicillin-resistant strains were resistant to cefdinir and cefpodoxime, with 74.8% and 94.1% susceptibility to cefotaxime and ceftriaxone, respectively. Cefditoren MIC(50)/MIC(90) (0.5/1 microg/ml) were lower than cefotaxime and ceftriaxone. Among amoxicillin non-susceptible strains, susceptibility to cefdinir and cefpodoxime was <10%, and susceptibility to cefotaxime decreased from 87.9% in the intermediate category to 63.0% in the resistant group. Cefditoren MIC(50)/MIC(90) (0.5/1 microg/ml) were lower than cefotaxime. In conclusion, the activity of cefixime, cefdinir and cefpodoxime was highly affected by penicillin/amoxicillin non-susceptibility, while parenteral third-generation cephalosporins exhibited higher intrinsic activity (MIC(90)=1 microg/ml for penicillin-resistant and 2 microg/ml for amoxicillin-resistant strains). Cefditoren exhibited one-dilution lower MIC(90) values for these strains, even against those of the most troublesome serotypes.

  20. [Detection of serinocarbapenemases Class A and other mechanisms of enzymatic resistance to β-lactams in enterobacteria strains with diminished susceptibility to carbapenems isolated of patients in a university hospital].

    Science.gov (United States)

    Lastra, Virginia de la; Rivas, Lina M; Silva, Francisco; Ulloa, M Teresa; Pinto, M Eugenia; Vidal, Mario

    2014-12-01

    The emergence of carbapenemase mediated resistance in Enterobacteriaceae has a strong clinical impact. This study aimed to do a genotypic and phenotypic characterization of the enzymatic resistance to β-lactams in clinical Enterobacteriaceae isolates with decreased susceptibility to carbapenems in a university medical center in Santiago. During April-September 2010 at Hospital Clinico Universidad de Chile, 23 isolates of carbapenem non susceptible Enterobacteriaceae were collected. We used PCR for the detection of class A carbapenemases (SME, IMI, NMC, GES and KPC) and the modified Hodge with the boronic acid test to phenotypically assess the presence of serine-carbapenemases. To assess extended spectrum β-lactamases (ESBLs) the CLSI phenotypic tests were performed. Metallo-β-lactamases (MBL) and AmpC were assessed with commercial tablets. 18/23 were Klebsiellapneumoniae and 5/23 strains were Enterobacter cloacae. All PCR to class A carbapenemases were negative. 3/23 strains (all E. cloacae), were positive to the Hodge modified test and 1/23, a K.pneumoniae, was positive to the boronic acid test. ESBLs were detected in 14/23 os the strains and AmpC in 5/23. No MBL was detected. No class A serine-carbapenemasa was detected. The decreased susceptibility to carbapenems is probably explained by the β-lactamase activity and due to porin loss.

  1. Botrytis pseudocinerea Is a Significant Pathogen of Several Crop Plants but Susceptible to Displacement by Fungicide-Resistant B. cinerea Strains.

    Science.gov (United States)

    Plesken, Cecilia; Weber, Roland W S; Rupp, Sabrina; Leroch, Michaela; Hahn, Matthias

    2015-10-01

    Botrytis cinerea is one of the most important pathogens worldwide, causing gray mold on a large variety of crops. Botrytis pseudocinerea has been found previously to occur together with B. cinerea in low abundance in vineyards and strawberry fields. Here, we report B. pseudocinerea to be common and sometimes dominant over B. cinerea on several fruit and vegetable crops in Germany. On apples with calyx end rot and on oilseed rape, it was the major gray mold species. Abundance of B. pseudocinerea was often negatively correlated with fungicide treatments. On cultivated strawberries, it was frequently found in spring but was largely displaced by B. cinerea following fungicide applications. Whereas B. cinerea strains with multiple-fungicide resistance were common in these fields, B. pseudocinerea almost never developed resistance to any fungicide even though resistance mutations occurred at similar frequencies in both species under laboratory conditions. The absence of resistance to quinone outside inhibitors in B. pseudocinerea was correlated with an intron in cytB preventing the major G143A resistance mutation. Our work indicates that B. pseudocinerea has a wide host range similar to that of B. cinerea and that it can become an important gray mold pathogen on cultivated plants. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  2. Biological characterization of Trypanosoma cruzi strains

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    Martínez-Díaz Rafael A

    2001-01-01

    Full Text Available Biological parameters of five Trypanosoma cruzi strains from different sources were determined in order to know the laboratory behaviour of natural populations. The parameters evaluated were growth kinetics of epimastigotes, differentiation into metacyclic forms, infectivity in mammalian cells grown in vitro and parasite susceptibility to nifurtimox, benznidazole and gentian violet. Differences in transformation to metacyclic, in the percentage of infected cells as well as in the number of amastigotes per cell were observed among the strains. Regarding to pharmacological assays, Y strain was the most sensitive to the three assayed compounds. These data demonstrate the heterogeneity of natural populations of T. cruzi, the only responsible of infection in humans.

  3. Treatment history and antimicrobial susceptibility results for Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni isolates from bovine respiratory disease cases submitted to the Iowa State University Veterinary Diagnostic Laboratory from 2013 to 2015.

    Science.gov (United States)

    Magstadt, Drew R; Schuler, Adlai M; Coetzee, Johann F; Krull, Adam C; O'Connor, Annette M; Cooper, Vickie L; Engelken, Terry J

    2017-10-01

    Bovine respiratory disease is the most costly disease facing the cattle industry. Increasing resistance to antimicrobial treatment has been presented as a significant contributing factor, often through summarized susceptibility testing data. We assessed the relationship between previous antimicrobial treatment and antimicrobial susceptibility results from isolates of Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni cultured from bovine respiratory cases submitted to the Iowa State University Veterinary Diagnostic Laboratory from 2013 to 2015. Antimicrobial susceptibility data from 1,251 bacterial isolates were included for analysis. More bacterial isolates from cattle that received antimicrobial treatment showed resistance compared to isolates from untreated cattle, and the percentage of resistant isolates increased as the number of antimicrobial treatments increased. Resistance to enrofloxacin, spectinomycin, tilmicosin, and tulathromycin was present in >75% of M. haemolytica isolates from cattle that had received 3 or more antimicrobial treatments; resistance to each of those 4 antimicrobials was present in ≤10% of M. haemolytica isolates from untreated cattle. Similar but less dramatic trends were apparent for isolates of P. multocida and H. somni. The percentage of multi-drug resistant bacterial isolates also increased with the number of treatments. Results of our study suggest that previous antimicrobial treatment may have a profound effect on antimicrobial susceptibility testing. Summarized susceptibility results from diagnostic laboratories should not be used to make generalized statements regarding trends in antimicrobial resistance without providing context regarding antimicrobial treatment history.

  4. Susceptibility of extended-spectrum-beta-lactamase-producing Enterobacteriaceae according to the new CLSI breakpoints.

    Science.gov (United States)

    Wang, Peng; Hu, Fupin; Xiong, Zizhong; Ye, Xinyu; Zhu, Demei; Wang, Yun F; Wang, Minggui

    2011-09-01

    In 2010 the Clinical and Laboratory Standards Institute (CLSI) lowered the susceptibility breakpoints of some cephalosporins and aztreonam for Enterobacteriaceae and eliminated the need to perform screening for extended-spectrum β-lactamases (ESBLs) and confirmatory tests. The aim of this study was to determine how many ESBL-producing strains of three common species of Enterobacteriaceae test susceptible using the new breakpoints. As determined with the CLSI screening and confirmatory tests, 382 consecutive ESBL-producing strains were collected at Huashan Hospital between 2007 and 2008, including 158 strains of Escherichia coli, 164 of Klebsiella pneumoniae, and 60 of Proteus mirabilis. Susceptibility was determined by the CLSI agar dilution method. CTX-M-, TEM-, and SHV-specific genes were determined by PCR amplification and sequencing. bla(CTX-M) genes alone or in combination with bla(SHV) were present in 92.7% (354/382) of these ESBL-producing strains. Forty-two (25.6%) strains of K. pneumoniae harbored SHV-type ESBLs alone or in combination. No TEM ESBLs were found. Utilizing the new breakpoints, all 382 strains were resistant to cefazolin, cefotaxime, and ceftriaxone, while 85.0 to 96.7% of P. mirabilis strains tested susceptible to ceftazidime, cefepime, and aztreonam, 41.8 to 45.6% of E. coli strains appeared to be susceptible to ceftazidime and cefepime, and 20.1% of K. pneumoniae were susceptible to cefepime. In conclusion, all ESBL-producing strains of Enterobacteriaceae would be reported to be resistant to cefazolin, cefotaxime, and ceftriaxone by using the new CLSI breakpoints, but a substantial number of ESBL-containing P. mirabilis and E. coli strains would be reported to be susceptible to ceftazidime, cefepime, and aztreonam, which is likely due to the high prevalence of CTX-M type ESBLs.

  5. Laboratory evaluation of Brevibacillus laterosporus strains as biocidal agents against Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) larvae.

    Science.gov (United States)

    Carramaschi, Isabel Nogueira; de Andrade Pereira, Lorrane; Dos Santos Baia, Vitor; Dos Santos Mallet, Jacenir Reis; de Carvalho Queiroz, Margareth Maria; Zahner, Viviane

    2017-06-01

    The biocidal activity of three strains of Brevibacillus laterosporus upon the post-embryonic developmental stages of Chrysomya megacephala was evaluated. Bioassays were performed to verify lethal and sub-lethal effects including ultra-structural changes in the midgut. Among the strains assayed, Shi3 presented the highest larval mortality rates, achieving 70% at a concentration of 1×108 spores/g of diet. Transmission electron microscopy revealed intestinal alterations caused by all strains tested. The findings of this study indicate that Shi3 represents a promising tool for use in the biocontrol of C. megacephala. Copyright © 2017. Published by Elsevier Inc.

  6. Perfil de susceptibilidade a antimicrobianos em amostras de cocos Gram-positivos, catalase negativos, isoladas de mastite subclínica bubalina Profile of antimicrobial susceptibility in strains of Gram positive cocos, negative catalase, isolated from buffalo subclinical mastitis

    Directory of Open Access Journals (Sweden)

    Maria C.E. Vianni

    2003-06-01

    the State of Rio de Janeiro. The test used was diffusion of disks in agar Müller Hinton, according to recommendations of the National Committee for Clinical Laboratory Standards - NCCLS. There were tested disks with ampicillin (10mg, cefalotin (30mg, cefotaxime (30mg, cefoxitin (30mg, cloranfenicol (30mg, eritromycin (15mg, gentamycin (10mg, nitrofurantoin (300mg, norfloxacin (10mg, penicillin (10 IU, tetracyclin (30mg and vancomycin (30mg. The results showed that with Lactococcus garvieae, the most efficient antimicrobial was nitrofurantoin, revealing 85.71% sensibility, followed by cefotaxime (61.90%, vancomycin (52.38%, norfloxacin (47.62& and cefalotin (47.62%. The highest resistance was developed against penicillin and ampicillin, with 95.24% resistance for the two antimicrobials. The susceptibility profile developed by the strains of Enterococcus gallinarum showed low sensibility against the tested antimicrobials; the highest resistance observed was against eritromycin and gentamycin, with 33.34% sensibility for both. The antimicrobial evaluation showed 100% resistance against vancomycin and tetracyclin, followed by cloranfenicol, penicillin, ampicillin, cefoxitin, cefotaxim, norfloxacin and nitrofurantoin; all of them showed a resistance of 83.33% with the samples tested.

  7. [Drug susceptibility and analysis using pulsed-field gel electrophoresis of Streptococcus pyogenes strains isolated from the patients with streptococcal toxic shock syndrome (STSS) in Japan].

    Science.gov (United States)

    Okuno, Rumi; Endoh, Miyoko; Shimojima, Yukako; Yanagawa, Yoshitoki; Morozumi, Satoshi; Oonaka, Kenji; Furuhata, Katsunori; Fukuyama, Masafumi

    2005-04-01

    Previously, we have performed T typing of Streptococcus pyogenes strains isolated from patients with streptococcal toxic shock syndrome (STSS) in Japan, and streptococcal pyrogenic exotoxin (SPE) typing for epidemiological examination. In this study, we conducted a drug sensitivity test using these strains, and investigated the results of gene analysis by pulse-field gel electrophoresis (PFGE) of S. pyogenes strains derived from patients with STSS, the patient's family, and patients other than those with STSS. To clarify the relationship between the host and bacterial factors, we investigated the association between clinical symptoms and T typing of the isolated strains/production of streptococcal pyrogenic exotoxin. There were no strains resistant to beta-lactams, and only 1 strain was resistant to multiple agents other than beta-lactams. The PFGE pattern of T1 type strains was classified into 2 ; the pattern was consistent between the strains derived from patients with STSS and those derived from the patient's family. The PFGE pattern of T3 type strains was classified into 5 (IV) ; Pattern I, which was most frequently observed, was detected in both the strains derived from patients with STSS/non-STSS. However, Patterns II and III were detected only in the strains derived from patients with non-STSS. Patterns IV and V were detected only in the strains derived from patients with STSS. When examining the association between clinical symptoms and bacterial factors, disseminated intravascular coagulation (DIC) was associated with T1-SPE B-producing strains, and pharyngitis was associated with T3-SPE A-producing strains. In the future, the relationship between the host and bacterial factors should be further investigated.

  8. The effect of two different Individually Ventilated Cage systems on anxiety-related behaviour and welfare in two strains of laboratory mouse.

    Science.gov (United States)

    Burman, O; Buccarello, L; Redaelli, V; Cervo, L

    2014-01-30

    The environment in which a laboratory animal is housed can significantly influence its behaviour and welfare, acting as a potential confounding factor for those studies in which it is utilised. This study investigated the impact of two Individually Ventilated Cage (IVC) housing systems on anxiety-related behaviour and welfare indicators in two common strains of laboratory mice. Subjects were juvenile female C57BL/6J and BALB/c mice (N=128) housed in groups of four in two different IVC systems for 7weeks. System One had air delivery at the cage 'cover' level at 75 ACH (Air Changes/Hour) and System Two had air delivery at the 'animal' level at 50 ACH. Mice were assessed twice a week (e.g. bodyweight) or at the end of the study (e.g. anxiety tests). Our results showed significant differences in anxiety-related behaviour between strains and housing systems. Mice in System Two, regardless of strain, defecated more in the Elevated Plus Maze (EPM), spent less time in the open arms of the EPM, and less time in the central zone of the Open Field (OF). Strain differences in anxiety-like behaviour were seen in the increased defecation by BALB/c mice in the OF and EPM and less time spent in the open arms of the EPM compared to C57BL/6J mice. These results suggest that different IVC housing systems can influence mouse behaviour in different ways, with mice of both strains studied exhibiting more anxiety-related behaviour when housed in System Two (air entry at the 'animal' level at 50 ACH), which could impact upon experimental data. © 2013. Published by Elsevier Inc. All rights reserved.

  9. Molecular characterization and antifungal susceptibility of Cryptococcus neoformans strains collected from a single institution in Lima, Peru : Revista Iberoamericana De Micologia

    NARCIS (Netherlands)

    Bejar, V.; Tello, M.; Garcia, R.; Guevara, J. M.; Gonzales, S.; Vergaray, G.; Valencia, E.; Abanto, E.; Ortega-Loayza, A. G.; Hagen, F.; Gutierrez, E. L.

    2015-01-01

    Background: Cryptococcosis is a fungal infection with a worldwide distribution, mainly caused by Cryptococcus neoformans and Cryptococcus gattii. Aims: To molecularly characterize the mating-types, serotypes, genotypes and antifungal susceptibility profiles of a set of retrospectively isolated C.

  10. Genome-wide sequencing and an open reading frame analysis of dichlorodiphenyltrichloroethane (DDT) susceptible (91-C) and resistant (91-R) Drosophila melanogaster laboratory populations

    Science.gov (United States)

    The Drosophila melanogaster 91-R and 91-C strains are of common origin, however, 91-R has been intensely selected for dichlorodiphenyltrichloroethane (DDT) resistance over six decades while 91-C has been maintained as the non-selected control strain. These fly strains represent a unique genetic res...

  11. An entomopathogenic strain of Beauveria bassiana against Frankliniella occidentalis with no detrimental effect on the predatory mite Neoseiulus barkeri: evidence from laboratory bioassay and scanning electron microscopic observation.

    Directory of Open Access Journals (Sweden)

    Shengyong Wu

    Full Text Available Among 28 isolates of Beauveria bassiana tested for virulence against F. occidentalis in laboratory bioassays, we found strain SZ-26 as the most potent, causing 96% mortality in adults at 1×10(7 mL(-1conidia after 4 days. The effect of the strain SZ-26 on survival, longevity and fecundity of the predatory mite Neoseiulus (Amblyseius barkeri Hughes were studied under laboratory conditions. The bioassay results showed that the corrected mortalities were less than 4 and 8% at 10 days following inoculation of the adult and the larvae of the predator, respectively, with 1×10(7 conidia mL(-1 of SZ-26. Furthermore, no fungal hyphae were found in dead predators. The oviposition and postoviposition durations, longevity, and fecundity displayed no significant differences after inoculation with SZ-26 using first-instar larvae of F. occidentalis as prey in comparison with untreated predator. In contrast, the preoviposition durations were significantly longer. Observations with a scanning electron microscope, revealed that many conidia were attached to the cuticles of F. occidentalis at 2 h after treatment with germ tubes oriented toward cuticle at 24 h, penetration of the insect cuticle at 36 h, and finally, fungal colonization of the whole insect body at 60 h. In contrast, we never observed penetration of the predator's cuticle and conidia were shed gradually from the body, further demonstrating that B. bassiana strain SZ-26 show high toxicity against F. occidentalis but no pathogenicity to predatory mite.

  12. Verification of new model for calculation of critical strain for the initialization of dynamic recrystallization using laboratory rolling

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    R. Fabík

    2009-10-01

    Full Text Available This paper presents a new model for calculation of critical strain for initialization of dynamic recrystallization. The new model reflects the history of forming in the deformation zone during rolling. In this region of restricted deformation, the strain rate curve for the surface of the strip exhibits two peaks. These are the two reasons why the onset of dynamic recrystallization DRX near the surface of the rolled part occurs later than in theory during strip rolling. The present model had been used in a program for simulation of forming processes with the aid of FEM and a comparison between the physical experiment and a mathematical model had been drawn.

  13. Simultaneous glucose and xylose uptake by an acetone/butanol/ethanol producing laboratory Clostridium beijerinckii strain SE-2.

    Science.gov (United States)

    Zhang, Jie; Zhu, Wen; Xu, Haipeng; Li, Yan; Hua, Dongliang; Jin, Fuqiang; Gao, Mintian; Zhang, Xiaodong

    2016-04-01

    Most butanol-producing strains of Clostridium prefer glucose over xylose, leading to a slower butanol production from lignocellulose hydrolysates. It is therefore beneficial to find and use a strain that can simultaneously use both glucose and xylose. Clostridium beijerinckii SE-2 strain assimilated glucose and xylose simultaneously and produced ABE (acetone/butanol/ethanol). The classic diauxic growth behavior was not seen. Similar rates of sugar consumption (4.44 mM glucose h(-1) and 6.66 mM xylose h(-1)) were observed suggesting this strain could use either glucose or xylose as the substrate and it has a similar capability to degrade these two sugars. With different initial glucose:xylose ratios, glucose and xylose were consumed simultaneously at rates roughly proportional to their individual concentrations in the medium, leading to complete utilization of both sugars at the same time. ABE production profiles were similar on different substrates. Transcriptional studies on the effect of glucose and xylose supplementation, however, suggests a clear glucose inhibition on xylose metabolism-related genes is still present.

  14. Relationship between high esterase activity and in vitro degradation of /sup 14/C-malathion by organophosphate-resistant and susceptible strains of the Kanzawa spider mite, Tetranychus kanzawai Kishida (Acarina: Tetranychidae), and their inhibition with specific synergists

    Energy Technology Data Exchange (ETDEWEB)

    Kuwahara, M. (National Inst. of Agricultural Sciences, Yatabe, Ibaraki (Japan)); Miyata, T.; Saito, T.; Eto, M.

    1981-08-01

    The relationship between the enzymes which catalyze hydrolysis of ..beta..-naphthyl acetate and degradation of malathion was studied in resistant and susceptible strains of the Kanzawa spider mite, Tetranychus kanzawai Kishida. The homogenate of resistant mites exhibited higher activity in the degradation of malathion in vitro than that of susceptible mites, but such activity was remarkably inhibited by the compound K-1, which also manifested a prominent synergism with malathion to resistant mites. Six esterase bands and three peaks of malathion degradation were resolved by agar-gel electrophoresis. Resistance to malathion was associated with increased esterase activity at E/sub 3/ and E/sub 4/ bands on which the main peak of malathion degradation was detected. The compound K-1 selectively inhibited the esterase and degradation activities. Compounds K-9 and IBP, on the other hand, selectively inhibited E/sub 1/ and E/sub 2/ bands which overlapped with the minor peaks of malanthion degradation.

  15. Identification and antifungal susceptibility of Candida species isolated from bloodstream infections in Konya, Turkey.

    Science.gov (United States)

    Dagi, Hatice Turk; Findik, Duygu; Senkeles, Cigdem; Arslan, Ugur

    2016-05-31

    In this study, our aim was to identify Candida species isolated from bloodstream infections and to determine their susceptibilities to various antifungal agents to demonstrate the local resistance profiles and to guide empirical treatment for clinicians. Two hundred Candida isolates (95 Candida albicans, 105 non-albicans Candida strains) were included in the study. Candida species were identified by conventional, biochemical and molecular methods. Antifungal susceptibility tests for amphotericin B, fluconazole, voriconazole, posaconazole, caspofungin and anidulafungin were performed with broth microdilution method according to the Clinical and Laboratory Standards Institute M27-A3 document. Of the 200 Candida strains, the most prevalent species were C. albicans (47.5 %), Candida glabrata (18.0 %) and Candida parapsilosis complex (14.0 %). All Candida species except for three (1.5 %) Candida kefyr strains were susceptible to amphotericin B. Only one (2.8 %) C. glabrata was resistant to fluconazole (MIC ≥ 64 μg/ml), and the others (97.2 %) exhibited dose-dependent susceptibility. All species, but C. glabrata strains, were susceptible to fluconazole. Resistance to voriconazole, posaconazole, caspofungin and anidulafungin was not detected in any strain. Candida albicans were susceptible to all antifungal drugs. Three C. kefyr strains were resistant to amphotericin B. Only one C. glabrata was resistant to fluconazole. All the strains were susceptible to voriconazole, posaconazole, caspofungin and anidulafungin. In vitro antifungal susceptibility tests should be performed to select of appropriate and effective antifungal therapy, and monitor the development of resistance.

  16. Ubiquitin conjugation of open reading frame F DNA vaccine leads to enhanced cell-mediated immune response and induces protection against both antimony-susceptible and -resistant strains of Leishmania donovani.

    Science.gov (United States)

    Sharma, Ankur; Madhubala, Rentala

    2009-12-15

    Resistance of Leishmania donovani to sodium antimony gluconate has become a critical issue in the current, prolonged epidemic in India. Hence, there is an urgent need for a vaccine that is protective against both antimony-susceptible and -resistant strains of L. donovani. The multigene LD1 locus located on chromosome 35 of Leishmania is amplified in approximately 15% of the isolates examined. The open reading frame F (ORFF), a potential vaccine candidate against visceral leishmaniasis, is part of the multigene LD1 locus. ORFF was expressed as a chimeric conjugate of ubiquitin to elicit an Ag-specific cell-mediated immune response. Analysis of the cellular immune responses of ubiquitin-conjugated ORFF (UBQ-ORFF) DNA-immunized, uninfected BALB/c mice demonstrated that the vaccine induced enhanced IFN-gamma-producing CD4(+) and CD8(+) T cells compared with nonubiquitinated ORFF DNA vaccine. Higher levels of IL-12 and IFN-gamma and the low levels of IL-4 and IL-10 further indicated that the immune responses with UBQ-ORFF were mediated toward the Th1 rather than Th2 type. Infection of immunized mice with either the antimony-susceptible (AG83) or -resistant (GE1F8R) L. donovani strain showed that UBQ-ORFF DNA vaccine induced higher protection when compared with ORFF DNA. UBQ-ORFF DNA-immunized and -infected mice showed a significant increase in IL-12 and IFN-gamma and significant down-regulation of IL-10. High levels of production of nitrite and superoxide, two macrophage-derived oxidants that are critical in controlling Leishmania infection, were observed in protected mice. The feasibility of using ubiquitinated-conjugated ORFF DNA vaccine as a promising immune enhancer for vaccination against both antimony-susceptible and -resistant strains of L. donovani is reported.

  17. Susceptibility of Spodoptera frugiperda (Lepidoptera: Noctuidae) strains from central Colombia to two insecticides, methomyl and lambda-cyhalothrin: a study of the genetic basis of resistance.

    Science.gov (United States)

    Ríos-Díez, J D; Saldamando-Benjumea, C I

    2011-10-01

    Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is an important pest of several crops in the western hemisphere. This insect has genetically differentiated into two host-associated populations: the corn (Zea mays L.) and the rice (Oryza sativa L.) strains. The corn strain also is found in cotton (Gossypium hirsutum L.) and sorghum and the rice strain in Bermuda grass [Cynodon dactylon (L.) Pers.] and millet. In the United States and Brazil, lines from corn, rice, Bermuda grass, and millet were used to evaluate the resistance of both strains to various insecticides, and found that the corn strain is more resistant than the rice strain. However, in these studies the larvae were not genotyped. In Colombia, genotyping of fall armyworm is necessary because the rice strain also can be found in corn fields. In this work, collected larvae from corn and rice fields from Tolima (central Colombia) were genotyped and evaluated for the resistance to methomyl and lambda-cyhalothrin. We found that the rice strain does not significantly differ in resistance to methomyl compared with the corn strain but it develops tolerance more rapidly to lambda-cyhalothrin. The eggs viability of treated females also was significantly affected by methomyl on each generation. The realized heritability of resistance was higher for lambda-cyhalothrin (0.23-0.42) than for methomyl (0.04-0.14). The number of generations needed for 10-fold increase in resistance is approximately 11.5 generations for methomyl and 6.5 for lambda-cyhalothrin. Finally, the genetic basis of resistance to both insecticides involves few recessive autosomal genes. The results obtained here suggest that methomyl is a better option than lambda-cyalothin to control fall armyworm.

  18. Temporal dynamics of the developing lung transcriptome in three common inbred strains of laboratory mice reveals multiple stages of postnatal alveolar development

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    Kyle J. Beauchemin

    2016-08-01

    Full Text Available To characterize temporal patterns of transcriptional activity during normal lung development, we generated genome wide gene expression data for 26 pre- and post-natal time points in three common inbred strains of laboratory mice (C57BL/6J, A/J, and C3H/HeJ. Using Principal Component Analysis and least squares regression modeling, we identified both strain-independent and strain-dependent patterns of gene expression. The 4,683 genes contributing to the strain-independent expression patterns were used to define a murine Developing Lung Characteristic Subtranscriptome (mDLCS. Regression modeling of the Principal Components supported the four canonical stages of mammalian embryonic lung development (embryonic, pseudoglandular, canalicular, saccular defined previously by morphology and histology. For postnatal alveolar development, the regression model was consistent with four stages of alveolarization characterized by episodic transcriptional activity of genes related to pulmonary vascularization. Genes expressed in a strain-dependent manner were enriched for annotations related to neurogenesis, extracellular matrix organization, and Wnt signaling. Finally, a comparison of mouse and human transcriptomics from pre-natal stages of lung development revealed conservation of pathways associated with cell cycle, axon guidance, immune function, and metabolism as well as organism-specific expression of genes associated with extracellular matrix organization and protein modification. The mouse lung development transcriptome data generated for this study serves as a unique reference set to identify genes and pathways essential for normal mammalian lung development and for investigations into the developmental origins of respiratory disease and cancer. The gene expression data are available from the Gene Expression Omnibus (GEO archive (GSE74243. Temporal expression patterns of mouse genes can be investigated using a study specific web resource (http://lungdevelopment.jax.org.

  19. Antimicrobial susceptibility of urinary Klebsiella pneumoniae and the emergence of carbapenem-resistant strains: A retrospective study from a university hospital in Morocco, North Africa

    Directory of Open Access Journals (Sweden)

    M.C. El Bouamri

    2015-03-01

    Conclusions: Antimicrobial susceptibility testing of urinary K. pneumoniae isolates showed a significantly high resistance to commonly used antimicrobial agents. These data highlight the need for regular surveillance of microbial resistance to improve infection control and guide the use of antimicrobial agents.

  20. Polymorphic Variation in Susceptibility and Metabolism of Triclosan-Resistant Mutants of Escherichia coli and Klebsiella pneumoniae Clinical Strains Obtained after Exposure to Biocides and Antibiotics

    Science.gov (United States)

    Curiao, Tânia; Marchi, Emmanuela; Viti, Carlo; Oggioni, Marco R.; Baquero, Fernando; Martinez, José Luis

    2015-01-01

    Exposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selected Escherichia coli and Klebsiella pneumoniae mutants. E. coli and K. pneumoniae mutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chloride (BKC), chlorhexidine (CHX) or sodium hypochlorite (SHC), and ampicillin or ciprofloxacin. Alterations in antimicrobial susceptibility and metabolism in mutants were tested using Phenotype MicroArrays. The expression of AcrAB pump and global regulators (SoxR, MarA, and RamA) was measured by quantitative reverse transcription-PCR (qRT-PCR), and the central part of the fabI gene was sequenced. The fitness costs of resistance were assessed by a comparison of relative growth rates. Triclosan-resistant (TRIr) and triclosan-hypersusceptible (TRIhs) mutants of E. coli and K. pneumoniae were obtained after selection with biocides and/or antibiotics. E. coli TRIr mutants, including those with mutations in the fabI gene or in the expression of acrB, acrF, and marA, exhibited changes in susceptibility to TRI, CHX, and antibiotics. TRIr mutants for which the TRI MIC was high presented improved metabolism of carboxylic acids, amino acids, and carbohydrates. In TRIr mutants, resistance to one antimicrobial provoked hypersusceptibility to another one(s). TRIr mutants had fitness costs, particularly marA-overexpressing (E. coli) or ramA-overexpressing (K. pneumoniae) mutants. TRI, BKC, and CIP exposure frequently yielded TRIr mutants exhibiting alterations in AraC-like global regulators (MarA, SoxR, and RamA), AcrAB-TolC, and/or FabI, and influencing antimicrobial susceptibility, fitness, and metabolism. These various phenotypes suggest a trade-off of different selective processes shaping the evolution toward antibiotic/biocide resistance and influencing other adaptive traits. PMID

  1. [Recommendations for the analysis of cumulated data in antimicrobial susceptibility in health institutions].

    Science.gov (United States)

    2010-04-01

    Due to the great variability in antimicrobial resistance patterns, local reports of cumulative antimicrobial susceptibility data are necessary in every health center. The purpose is to guide clinical decisions and the early detection of patterns that allow preventive measures to avoid dissemination of resistant strains. The main objective of this guide is to provide recommendations for the analysis of antimicrobial susceptibility data and elaboration of a local report. Recommendations provided in this guide are based on the Clinical and Laboratory Standards Institute (CLSI) document "Analysis and Presentation of Cumulative Antimicrobial Susceptibility Test Data" (3). Key aspects related to information gathering and data processing, analysis and presentation are described.

  2. [Antimicrobial resistance of Bartonella bacilliformis strains from regions endemic to bartonellosis in Peru].

    Science.gov (United States)

    Mendoza-Mujica, Giovanna; Flores-León, Diana

    2015-10-01

    To evaluate in vitro antimicrobial susceptibility to chloramphenicol (CHL) and ciprofloxacin (CIP) in strains of Bartonella bacilliformis from areas that are endemic to Bartonellosis in Peru, through three laboratory methods. Antimicrobial susceptibility to CHL and CIP from 100 strains of Bartonella bacilliformis isolated in patients from the regions of Ancash, Cusco, Cajamarca, Lima and La Libertad were evaluated. Strains were evaluated by: disk diffusion, E-test and agar dilution. 26% of the strains of Bartonella bacilliformis evaluated were resistant to CIP and 1% to CHL. Similar patterns of antimicrobial sensitivity / resistance were obtained in all three methods. Bartonella bacilliformis strains circulating in Peru have high levels of in vitro resistance to CIP, so it is advisable to expand research on the use of drug treatment regimens of the Bartonellosis. The methods of E-test and disk diffusion were the most suitable for assessment in vitro of antimicrobial susceptibility of the microorganism.

  3. Challenges and advances in systems biology analysis of Bacillus spore physiology; molecular differences between an extreme heat resistant spore forming Bacillus subtilis food isolate and a laboratory strain.

    Science.gov (United States)

    Brul, Stanley; van Beilen, Johan; Caspers, Martien; O'Brien, Andrea; de Koster, Chris; Oomes, Suus; Smelt, Jan; Kort, Remco; Ter Beek, Alex

    2011-04-01

    Bacterial spore formers are prime organisms of concern in the food industry. Spores from the genus Bacillus are extremely stress resistant, most notably exemplified by high thermotolerance. This sometimes allows surviving spores to germinate and grow out to vegetative cells causing food spoilage and possible intoxication. Similar issues though more pending toward spore toxigenicity are observed for the anaerobic Clostridia. The paper indicates the nature of stress resistance and highlights contemporary molecular approaches to analyze the mechanistic basis of it in Bacilli. A molecular comparison between a laboratory strain and a food borne isolate, very similar at the genomic level to the laboratory strain but generating extremely heat resistant spores, is discussed. The approaches cover genome-wide genotyping, proteomics and genome-wide expression analyses studies. The analyses aim at gathering sufficient molecular information to be able to put together an initial framework for dynamic modelling of spore germination and outgrowth behaviour. Such emerging models should be developed both at the population and at the single spore level. Tools and challenges in achieving the latter are succinctly discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. In vitro susceptibility to pentavalent antimony in Leishmania infantum strains is not modified during in vitro or in vivo passages but is modified after host treatment with meglumine antimoniate.

    Science.gov (United States)

    Carrió, Jaume; Portús, Montserrat

    2002-05-02

    Leishmaniasis is a common parasitic disease in Southern Europe, caused by Leishmania infantum. The failures of current treatment with pentavalent antimonials are partially attributable to the emergence of antimony-resistant Leishmania strains. This study analyses the in vitro susceptibility to pentavalent antimony of intracellular amastigotes from a range of L. infantum strains, derived from the same infected animal, during in vitro and in vivo passages and after host treatment with meglumine antimoniate. SbV-IC50 values for strains from two distinct isolates from the same host and one stock after two years of culture in NNN medium and posterior passage to hamster were similar (5.0 +/- 0.2; 4.9 +/- 0.2 and 4.4 +/- 0.1 mgSbV/L, respectively). In contrast, a significant difference (P resistance after drug pressure in experimentally infected dogs increased over repeated drug administration (6.4 +/- 0.5 mgSbV/L after first treatment vs. 8.6 +/- 1.4 mgSbV/L after the second) (P leishmaniasis in endemic areas on the emergence of Leishmania antimony-resistant strains.

  5. ILG1 : a new integrase-like gene that is a marker of bacterial contamination by the laboratory Escherichia coli strain TOP10F'.

    Science.gov (United States)

    Tian, Wenzhi; Chua, Kevin; Strober, Warren; Chu, Charles C

    2002-07-01

    Identification of differentially expressed genes between normal and diseased states is an area of intense current medical research that can lead to the discovery of new therapeutic targets. However, isolation of differentially expressed genes by subtraction often suffers from unreported contamination of the resulting subtraction library with clones containing DNA sequences not from the original RNA samples. Subtraction using cDNA representational difference analysis (RDA) was performed on human B cells from normal or common variable immunodeficiency patients. The material remaining after the subtraction was cloned and individual clones were sequenced. The sequence of one clone with similarity to integrases (ILG1, integrase-like gene-1) was used to obtain the full length cDNA sequence and as a probe for the presence of this sequence in RNA or genomic DNA samples. After five rounds of cDNA RDA, 23.3% of the clones from the resulting subtraction library contained Escherichia coli DNA. In addition, three clones contained the sequence of a new integrase, ILG1. The full length cDNA sequence of ILG1 exhibits prokaryotic, but not eukaryotic, features. At the DNA level, ILG1 is not similar to any known gene. At the protein level, ILG1 has 58% similarity to integrases from the cryptic P4 bacteriophage family (S clade). The catalytic domain of ILG1 contains the conserved features found in site-specific recombinases. The critical residues that form the catalytic active site pocket are conserved, including the highly conserved R-H-R-Y hallmark of these recombinases. Interestingly, ILG1 was not present in the original B cell populations. By probing genomic DNA, ILG1 could only be detected in the E. coli TOP10F' strain used in our laboratory for molecular cloning, but not in any of its precursor strains, including TOP10. Furthermore, bacteria cultured from the mouth of the laboratory worker who performed cDNA RDA were also positive for ILG1. In the course of our studies using c

  6. Advances in rapid identification and susceptibility testing of bacteria in the clinical microbiology laboratory: implications for patient care and antimicrobial stewardship programs

    Directory of Open Access Journals (Sweden)

    Florian P. Maurer

    2017-03-01

    Full Text Available Early availability of information on bacterial pathogens and their antimicrobial susceptibility is of key importance for the management of infectious diseases patients. Currently, using traditional approaches, it usually takes at least 48 hours for identification and susceptibility testing of bacterial pathogens. Therefore, the slowness of diagnostic procedures drives prolongation of empiric, potentially inappropriate, antibacterial therapies. Over the last couple of years, the improvement of available techniques (e.g. for susceptibility testing, DNA amplification assays, and introduction of novel technologies (e.g. MALDI-TOF has fundamentally changed approaches towards pathogen identification and characterization. Importantly, these techniques offer increased diagnostic resolution while at the same time shorten the time-to-result, and are thus of obvious importance for antimicrobial stewardship. In this review, we will discuss recent advances in medical microbiology with special emphasis on the impact of novel techniques on antimicrobial stewardship programs.

  7. Advances in Rapid Identification and Susceptibility Testing of Bacteria in the Clinical Microbiology Laboratory: Implications for Patient Care and Antimicrobial Stewardship Programs.

    Science.gov (United States)

    Maurer, Florian P; Christner, Martin; Hentschke, Moritz; Rohde, Holger

    2017-03-30

    Early availability of information on bacterial pathogens and their antimicrobial susceptibility is of key importance for the management of infectious diseases patients. Currently, using traditional approaches, it usually takes at least 48 hours for identification and susceptibility testing of bacterial pathogens. Therefore, the slowness of diagnostic procedures drives prolongation of empiric, potentially inappropriate, antibacterial therapies. Over the last couple of years, the improvement of available techniques (e.g. for susceptibility testing, DNA amplification assays), and introduction of novel technologies (e.g. MALDI-TOF) has fundamentally changed approaches towards pathogen identification and characterization. Importantly, these techniques offer increased diagnostic resolution while at the same time shorten the time-to-result, and are thus of obvious importance for antimicrobial stewardship. In this review, we will discuss recent advances in medical microbiology with special emphasis on the impact of novel techniques on antimicrobial stewardship programs.

  8. Incidence of oral indigenous bacteria in causative strains isolated from blood cultures in 759 laboratory-confirmed cases of bacteremia

    OpenAIRE

    Shinya Yura; Sadaya Matano

    2012-01-01

    Background: The incidence of oral indigenous bacteria in cases of bacteremia has been reported in only a few studies. We investigated the annual incidence of oral indigenous bacteria isolated in blood cultures from patients with bacteremia and call into consideration the impact of oral health measures implemented at our facility. Methods: In the period from 2001 to 2006, 759 laboratory-confirmed cases of bacteremia were reported and subsequently analyzed in this study. The incidences of the c...

  9. Phenotypic and Genotypic Features of a Salmonella Heidelberg Strain Isolated in Broilers in Brazil and Their Possible Association to Antibiotics and Short-Chain Organic Acids Resistance and Susceptibility.

    Science.gov (United States)

    Santin, Elizabeth; Hayashi, Ricardo Mitsuo; Wammes, Jessica Caroline; Gonzalez-Esquerra, Ricardo; Carazzolle, Marcelo Falsarella; Freire, Caio César de Melo; Monzani, Paulo Sérgio; da Cunha, Anderson Ferreira

    2017-01-01

    Salmonella enterica serovar Heidelberg is a human pathogen also found in broilers. A strain (UFPR1) has been associated with field reports of resistance to short-chain organic acids (SCOA) in broilers in the South of Brazil, but was susceptible to a Bacillus subtilis-based probiotic added in feed in a related study. This work aimed to (i) report clinical symptoms caused by SH UFPR1 in broilers, (ii) study its susceptibility to some antibiotics in vitro, and (iii) SCOA in vivo; and (iv) relate these phenotypic observations with its genome characteristics. Two in vivo trials used 1-day-old chicks housed for 21 days in 8 sterilized isolated negative pressure rooms with 4 battery cages of 12 birds each. Birds were challenged or not with 107 CFU/bird of SH UFPR1 orally and exposed or not to SCOA in a 2 × 2 factorial design. Zootechnical parameters were unaffected (P > 0.05), no clinical signs were observed, and few cecal and hepatic histologic and immune-related alterations were seen, in birds challenged with SH. Formic and propionic acids added together in drinking water, fumaric and benzoic acid in feed (Trial 1), and coated calcium butyrate in feed (Trial 2) did not reduce the SH isolation frequencies seen in cecum and liver in broilers after SH challenge (P > 0.05). SH UFPR1 was susceptible to amikacin, amoxicillin + clavulanate, ceftiofur, cephalexin, doxycycline and oxytetracycline; and mildly susceptible to ampicillin + sulbactam, cephalothin, ciprofloxacin, enrofloxacin, and gentamycin in an in vitro minimum inhibitory concentration model using Mueller-Hinton agar. The whole genome of SH UFPR1 was sequenced and consisted of a circular chromosome, spanning 4,760,321 bp with 52.18% of GC-content encoding 84 tRNA, 22 rRNA, and 4,427 protein-coding genes. The comparison between SH UFPR1 genome and a multidrug-resistant SL476 strain revealed 11 missing genomic fragments and 5 insertions related to bgt, bgr, and rpoS genes. The deleted genes

  10. Increasing trend of fluconazole-non-susceptible Cryptococcus neoformans in patients with invasive cryptococcosis: a 12-year longitudinal study.

    Science.gov (United States)

    Chen, Yi-Chun; Chang, Tzu-Yao; Liu, Jien-Wei; Chen, Fang-Ju; Chien, Chun-Chih; Lee, Chen-Hsiang; Lu, Cheng-Hsien

    2015-07-22

    This study aimed to investigate the rate of fluconazole-non-susceptible Cryptococcus neoformans in Southern Taiwan for the period 2001-2012 and analyze the risk factors for acquiring it among patients with invasive cryptococcosis. All enrolled strains were isolated from blood or cerebrospinal fluid samples of the included patients. If a patient had multiple positive results for C. neoformans, only the first instance was enrolled. Susceptibility testing was performed using the Clinical and Laboratory Standards Institutes M27-A3 broth micro-dilution method. The MIC interpretative criteria for susceptibility to fluconazole were ≤ 8 μg/ml. A total of 89 patients were included. Patients (n = 59) infected by fluconazole-susceptible strains were compared with those (n = 30) infected by non-susceptible strains. The patients' demographic and clinical characteristics were analyzed. The rate of fluconazole-non-susceptible C. neoformans in the study period significantly increased over time (p fluconazole-non-susceptible C. neoformans. The rate of fluconazole-non-susceptible C. neoformans has significantly increased recently. Continuous and large-scale anti-fungal susceptibility tests for C. neoformans are warranted to confirm this trend.

  11. Antibacterial susceptibility of new copper(II N-pyruvoyl anthranilate complexes against marine bacterial strains – In search of new antibiofouling candidate

    Directory of Open Access Journals (Sweden)

    Reda F.M. Elshaarawy

    2016-11-01

    Full Text Available Biofouling is a serious problem and very difficult to overcome, since the marine biofilm-producing microorganisms resist the host defense mechanism and antibiotic therapy. Therefore, there is an urgent need to develop potent anti-biofouling agent to effectively eradicate unwanted biofilms. Our work represents antibacterial susceptibility and antibiofilm forming assay of new copper(II N-pyruvoyl anthranilate architectures (4a–d against Staphylococcus aureus and Escherichia coli, marine isolates. The preliminary biofilm susceptibility tests revealed that, the most potent staphylococcalcidal (MIC/MBC = 9.25/10.50 mM and E. coli-cidal (MIC/MBC = 13.25/13.50 mM agent, 4d, exhibits significant biofilm inhibition. Complex 4d can therefore provide an antibiofilm-forming agent candidate to curb the formation of biofilms.

  12. External Quality Assurance System (EQAS) of the WHO Global Salmonella Surveillance and Laboratory Support Project (Global Salm-Surv) Results from 2001

    DEFF Research Database (Denmark)

    Petersen, A.; Aarestrup, Frank Møller; Evans, M.C.

    susceptibility testing. A total of 103 laboratories in 60 countries participated. For serotyping, 78% of the results were correct. For susceptibility testing, 91% of the results were in agreement with the expected results. However, 17% of the performed tests with the E. coli ATCC 25922 reference strain were out......An international collaborative study on serotyping and antimicrobial susceptibility testing of eight Salmonella enterica strains was performed to enhance the capacity of national and regional reference laboratories in WHO Global Salm-Surv to conduct Salmonella serotyping and antimicrobial...

  13. In vitro antibiotic susceptibilities of Yersinia pestis determined by broth microdilution following CLSI methods.

    Science.gov (United States)

    Heine, Henry S; Hershfield, Jeremy; Marchand, Charles; Miller, Lynda; Halasohoris, Stephanie; Purcell, Bret K; Worsham, Patricia L

    2015-04-01

    In vitro susceptibilities to 45 antibiotics were determined for 30 genetically and geographically diverse strains of Yersinia pestis by the broth microdilution method at two temperatures, 28°C and 35°C, following Clinical and Laboratory Standards Institute (CLSI) methods. The Y. pestis strains demonstrated susceptibility to aminoglycosides, quinolones, tetracyclines, β-lactams, cephalosporins, and carbapenems. Only a 1-well shift was observed for the majority of antibiotics between the two temperatures. Establishing and comparing antibiotic susceptibilities of a diverse but specific set of Y. pestis strains by standardized methods and establishing population ranges and MIC50 and MIC90 values provide reference information for assessing new antibiotic agents and also provide a baseline for use in monitoring any future emergence of resistance. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  14. Antimicrobial Resistance of Staphylococcal Strains Isolated from Various Pathological Products

    Directory of Open Access Journals (Sweden)

    Laura-Mihaela SIMON

    2010-12-01

    Full Text Available Background: The optimal choice of antimicrobial therapy is an important problem in hospital environment in which the selection of resistant and virulent strains easy occurs. S. aureus and especially MRSA(methicillin-resistant S. aureus creates difficulties in both treatment and prevention of nosocomial infections. Aim: The purpose of this study is to determine the sensitivity and the resistance to chemotherapy of staphylococci strains isolated from various pathological products. Material and Method: We identified Staphylococccus species after morphological appearance, culture properties, the production of coagulase, hemolisines and the enzyme activity. The susceptibility tests were performed on Mueller-Hinton medium according to CLSI (Clinical and Laboratory Standards Institute. Results: The strains were: MSSA (methicillin-susceptible S. aureus (74%, MRSA (8%, MLS B (macrolides, lincosamides and type B streptogramines resistance (12% and MRSA and MLS B (6%. MRSA strains were more frequently isolated from sputum. MRSA associated with the MLS B strains were more frequently isolated from pus. MLS B strains were more frequently isolated from sputum and throat secretions. All S. aureus strains were susceptible to vancomycin and teicoplanin. Conclusions: All staphylococcal infections require resistance testing before treatment. MLS B shows a high prevalence among strains of S. aureus. The association between MLS B and MRSA remains a major problem in Romania.

  15. Ozone gas effectively kills laboratory strains of Trichophyton rubrum and Trichophyton mentagrophytes using an in vitro test system.

    Science.gov (United States)

    Gupta, A K; Brintnell, W

    2014-06-01

    Ozone gas possesses antimicrobial potential against many microorganisms, however limited data exist on its effect on the keratinophilic dermatophyte fungi Trichophyton rubrum and Trichophyton mentagrophytes; two organisms commonly isolated as the etiological agent in onychomycosis and tinea pedis patients. We utilized a commercial ozone gas generation device for testing the fungicidal effects of ozone on ATCC strains of Trichophyton rubrum and Trichophyton mentagrophytes. We demonstrated that ozone gas is effective in killing > 99% of viable fungi present in various experimental systems. This work represents a proof of principle regarding ozone gas and its fungicidal effect on dermatophyte fungi. From these findings, further ozone gas studies will be conducted to develop a novel adjunct therapy for use in parallel with current antifungal medications and/or devices to better treat onychomycosis and tinea pedis patients in the short and long term.

  16. Genetic characterization of commensal Escherichia coli isolated from laboratory rodents.

    Science.gov (United States)

    Loong, Shih Keng; Mahfodz, Nur Hidayana; Che Mat Seri, Nurul Asma Anati; Mohamad Wali, Haryanti Azura; Abd Gani, Syahar Amir; Wong, Pooi-Fong; AbuBakar, Sazaly

    2016-01-01

    Escherichia coli, a commensal in the intestines of vertebrates, is capable of colonizing many different hosts and the environment. Commensal E. coli strains are believed to be the precursor of pathogenic strains by means of acquisition of antimicrobial resistant and virulence genes. Laboratory rodents are inherently susceptible to numerous known infectious agents, which could transfer virulence determinants to commensal E. coli. Hence, in this study, the genetic structure of commensal E. coli found in laboratory rodents and their antimicrobial resistance profiles were investigated. E. coli strains belonging to phylogroup A were the predominant strain obtained from the animals used in the study. Four novel sequence types (ST746, ST747, ST748 and ST749) were discovered using the multi locus sequence typing, together with one common ST357 in the gastrointestinal tract, liver and, the trachea and lung. Serotyping demonstrated that these commensal E. coli strains were non-Shiga toxin-producers. Phenotypic and genotypic analyses of extended spectrum beta lactamases were also negative. These findings implied that the E. coli strains recovered from the laboratory rodents were truly commensal in nature. Further study is required to investigate the possible influence of gender on the susceptibility of hosts to E. coli colonization in laboratory rodents.

  17. Susceptibility of Aedes albopictus and Aedes aegypti to three imported Chikungunya virus strains, including the E1/226V variant in Taiwan

    Directory of Open Access Journals (Sweden)

    Tien-Huang Chen

    2015-06-01

    Conclusion: We concluded that the risk of CHIKV in Taiwan is high in all distribution areas of Ae. aegypti and Ae. albopictus for the CESA genotype and that the E1/226V variant virus strain presents an even higher risk.

  18. Antibiotic susceptibility profiles of some Vibrio strains isolated from wastewater final effluents in a rural community of the Eastern Cape Province of South Africa

    Directory of Open Access Journals (Sweden)

    Igbinosa Etinosa O

    2010-05-01

    Full Text Available Abstract Background To evaluate the antibiogram and antibiotic resistance genes of some Vibrio strains isolated from wastewater final effluents in a rural community of South Africa. V. vulnificus (18, V. metschnikovii (3, V. fluvialis (19 and V. parahaemolyticus (12 strains were isolated from final effluents of a wastewater treatment plant (WWTP located in a rural community of South Africa. The disk diffusion method was used for the characterization of the antibiogram of the isolates. Polymerase chain reaction (PCR was employed to evaluate the presence of established antibiotic resistance genes using specific primer sets. Results The Vibrio strains showed the typical multidrug-resistance phenotype of an SXT element. They were resistant to sulfamethoxazole (Sul, trimethoprim (Tmp, cotrimoxazole (Cot, chloramphenicol (Chl, streptomycin (Str, ampicillin (Amp, tetracycline (Tet nalidixic acid (Nal, and gentamicin (Gen. The antibiotic resistance genes detected includes dfr18 and dfrA1 for trimethoprim; floR, tetA, strB, sul2 for chloramphenicol, tetracycline, streptomycin and sulfamethoxazole respectively. Some of these genes were only recently described from clinical isolates, demonstrating genetic exchange between clinical and environmental Vibrio species. Conclusions These results demonstrate that final effluents from wastewater treatment plants are potential reservoirs of various antibiotics resistance genes. Moreover, detection of resistance genes in Vibrio strains obtained from the wastewater final effluents suggests that these resistance determinants might be further disseminated in habitats downstream of the sewage plant, thus constituting a serious health risk to the communities reliant on the receiving waterbodies.

  19. Genetic Characterization of Spondweni and Zika Viruses and Susceptibility of Geographically Distinct Strains of Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus (Diptera: Culicidae) to Spondweni Virus

    Science.gov (United States)

    2016-10-26

    albopictus [19,22], and Culex quinquefasciatus (C. F. Junqueira 105 Ayres pers. comm.). 106 107 108 Methods 109 110 Virus strains and virus...has been discussed as a potential vector in Brazil (C. F. 237 Junqueira Ayres pers. comm.). Early work demonstrated that Ae. aegypti was a 238

  20. The role of MHC haplotypes H2d/H2b in mouse resistance/susceptibility to cyst formation is influenced by the lineage of infective Toxoplasma gondii strain

    Directory of Open Access Journals (Sweden)

    Marianne G. Resende

    2008-03-01

    Full Text Available Toxoplasma gondii strains displaying the Type I/III genotype are associated with acquired ocular toxoplasmosis in humans. Here, we used a mice model to characterize some immunological mechanisms involved in host resistance to infection with such strains. We have chosen the Type I/III strains D8, G2 and P-Br, which cause a chronic infection in mice that resembles human toxoplamosis. Mice deficient of molecules MyD88, IFN-gamma, and IL-12 were susceptible to all three parasite strains. This finding indicates the importance of innate mechanisms in controlling infection. On the other hand, MHC haplotype did not influenced resistance/susceptibility; since mice lineages displaying a same genetic background but different MHC haplotypes (H2b or H2d developed similar mortality and cyst numbers after infection with those strains. In contrast, the C57BL/6 genetic background, and not MHC haplotype, was critical for development of intestinal inflammation caused by any of the studied strains. Finally, regarding effector mechanisms, weobserved that B and CD8+ T lymphocytes controlled survival,whereas the inducible nitric oxide synthase influenced cyst numbers in brains of mice infected with Type I/III strains. These findings are relevant to further understanding of the immunologic mechanisms involved in host protection and pathogenesis during infection with T. gondii.Cepas de Toxoplasma gondii que apresentam o genótipo I/III são associadas a toxoplasmose ocular adquirida em humanos. No presente trabalho, nós utilizamos um modelo da doença em camundongos para caracterizar mecanismos imunológicos envolvidos na resistência do hospedeiro à infecção por aquelas cepas. Escolhemos as cepas D8, G2 e P-Br, que causam infecção crônica em camundongos, semelhante à toxoplasmose humana. Camundongos deficientes em MyD88, IFN-G e IL-12 foram susceptíveis a infecções com todas as três linhagens do parasita. Esses dados indicam a importância de mecanismos

  1. Effect of culture media and nutrients on biofilm growth kinetics of laboratory and clinical strains of Enterococcus faecalis.

    Science.gov (United States)

    Seneviratne, C J; Yip, J W Y; Chang, J W W; Zhang, C F; Samaranayake, L P

    2013-10-01

    Enterococcus faecalis is a bacterial pathogen that is often associated with endodontic infections. Biofilm formation is a key virulence attribute in the pathogenicity of E. faecalis. In the present study, we comprehensively examined the effect of various culture media and nutrients on the development of E. faecalis biofilms. A reference strain and a clinical isolate of E. faecalis were used in all experiments for comparison. Commonly used liquid culture media with different nutrient compositions were used to support the development of E. faecalis biofilms in a time-dependent assay. E. faecalis biofilms were quantified by colony forming unit (CFU) and crystal violet (CV) assays. Biofilm architecture and cellular viability were evaluated by scanning electron microscopy and confocal laser scanning microscopy. Growth kinetics evaluated by CFU and CV assays and by microscopy showed that E. faecalis biofilms reached maturity at 72h. "Pg broth" (Tryptic Soy Broth with yeast extract, hemen and vitamin K) promoted E. faecalis biofilm formation more than Brain Heart Infusion broth or Tryptic Soy Broth. Addition of 2% glucose enhanced biofilm formation. Thus, it seems that nutrients such as hemen, vitamin K and glucose are important for E. faecalis for the formation of biofilms. The present study demonstrated that nutrient-rich media containing glucose enhances the formation of E. faecalis biofilms, which exhibit maturation at 72h. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Antimicrobial susceptibility of Helicobacter pylori and mechanisms of clarithromycin resistance in strains isolated from patients in Uruguay Susceptibilidad a los antomicrobianos Helicobacter pylori y mecanismo de resistencia a claritromicina en cepas aisladas de pacientes uruguayos

    Directory of Open Access Journals (Sweden)

    M. E. Torres-Debat

    2009-11-01

    Full Text Available The prevalence and mechanisms of antibiotic resistance of Helicobacter pylori have not yet been investigated in Uruguay. The objective of this study was to assess the susceptibility of H. pylori to the most frequently used antibiotics and to determine the mechanism of resistance to clarithromycin. Seventy-nine isolates were obtained from gastric biopsies of 50 adult patients during two periods, 2001 and 2006. The former group enrolled the general population (GP, the latter group Afro-descendant (AD subjects. The minimum inhibitory concentrations of clarithromycin, amoxicillin, tetracycline, metronidazole, and levofloxacin were determined using the E-test technique. Amplification was achieved through PCR and nucleic acid sequencing to detect mutations in the site of action of clarithromycin in the rRNA gene 23S. No amoxicillin or tetracycline-resistant strains were found. Clarithromycin resistance was found in 12% of the patients overall: 19.4% resistance in AD patients and no resistance in the GP group. This difference was statistically significant. The highest resistance was seen with metronidazole (36%, present in similar proportions in the two groups: 36.8% (GP and 35.5% (AD. One GP patient and one AD patient had levofloxacin-resistant strains. Sequencing analysis of gene 23S rRNA showed that only mutation in position 2143 was presented in all clarithromycin-resistant strains.

  3. Antimicrobial susceptibility profiles of thermophilic campylobacters isolated from patients in the town of Niš

    Directory of Open Access Journals (Sweden)

    Miljković-Selimović Biljana

    2009-01-01

    Full Text Available Background/Aim. In some clinical forms of human Campylobacter infections, such as prolonged diarrhea or associated with postinfections sequels, antibacterial treatment is necessary. The aim of the present study was to evaluate the antimicrobial susceptibility of thermophilic Campylobacter strains isolated from patients with diarrhea, as well as from patients with diarrhea followed by postinfections sequels, to drugs used in the therapy of enterocolitis, and to nalidixic acid used in laboratory identification and differentiation of thermophilic Campylobacter spp. Methods. We studied the antimicrobial susceptibility profiles of 131 Campylobacter strains isolated from patients with diarrhea (122 strains, diarrhea associated with rheumatic disorders (8 strains, and one strain isolated from a patient with Guillain-Barré Syndrome following Campylobacter enterocolitis. Susceptibility testing to erythromycin, gentamicin, tetracycline, chloramphenicol, ciprofloxacin and nalidixic acid was performed by the agar dilution method. Results. In the strains we investigated, resistance to gentamicin and chloramphenicol was not recorded, whereas a low rate of strains resistant to erythromycin (2.4%, a higher prevalence of strains resistant to tetracycline (9.9%, and a high level of resistance to ciprofloxacin (29.8% and nalidixic acid (33.3% were registered. All strains resistant to nalidixic acid were also resistant to ciprofloxacin. In addition, there was no difference in the occurrence of resistance between strains isolated from patients with diarrhea as compared to those isolated from patients with diarrhea followed by postinfection disorders. Conclusion. The fact that the most of Campylobacter strains were sensitive to erythromycin and all to gentamicin, makes erythromycin an antibiotic of choice in the treatment of Campylobacter diarrhea and gentamicin when parenteral therapy should be administered. Resistance to tetracycline and, especially, ciprofloxacin

  4. Antimicrobial susceptibility profiles of thermophilic campylobacters isolated from patients in the town of Nis.

    Science.gov (United States)

    Miljković-Selimović, Biljana; Babić, Tatjana; Kocić, Branislava; Ristić, Ljiljana

    2009-07-01

    In some clinical forms of human Campylobacter infections, such as prolonged diarrhea or associated with postinfections sequels, antibacterial treatment is necessary. The aim of the present study was to evaluate the antimicrobial susceptibility of thermophilic Campylobacter strains isolated from patients with diarrhea, as well as from patients with diarrhea followed by postinfections sequels, to drugs used in the therapy of enterocolitis, and to nalidixic acid used in laboratory identification and differentiation of thermophilic Campylobacter spp. We studied the antimicrobial susceptibility profiles of 131 Campylobacter strains isolated from patients with diarrhea (122 strains), diarrhea associated with rheumatic disorders (8 strains), and one strain isolated from a patient with Guillain-Barré Syndrome following Campylobacter enterocolitis. Susceptibility testing to erythromycin, gentamicin, tetracycline, chloramphenicol, ciprofloxacin and nalidixic acid was performed by the agar dilution method. In the strains we investigated, resistance to gentamicin and chloramphenicol was not recorded, whereas a low rate of strains resistant to erythromycin (2.4%), a higher prevalence of strains resistant to tetracycline (9.9%), and a high level of resistance to ciprofloxacin (29.8%) and nalidixic acid (33.3%) were registered. All strains resistant to nalidixic acid were also resistant to ciprofloxacin. In addition, there was no difference in the occurrence of resistance between strains isolated from patients with diarrhea as compared to those isolated from patients with diarrhea followed by postinfection disorders. The fact that the most of Campylobacter strains were sensitive to erythromycin and all to gentamicin, makes erythromycin an antibiotic of choice in the treatment of Campylobacter diarrhea and gentamicin when parenteral therapy should be administered. Resistance to tetracycline and, especially, ciprofloxacin, necessitates antibiotic susceptibility testing.

  5. Extended biofilm susceptibility assay for Staphylococcus aureus bovine mastitis isolates: evidence for association between genetic makeup and biofilm susceptibility.

    Science.gov (United States)

    Melchior, M B; van Osch, M H J; Lam, T J G M; Vernooij, J C M; Gaastra, W; Fink-Gremmels, J

    2011-12-01

    Staphylococcus aureus is one of the most prevalent causes of bovine mastitis. The antimicrobial treatment of this disease is currently based on antimicrobial susceptibility tests according to Clinical and Laboratory Standards Institute standards. However, various authors have shown a discrepancy between the results of this standard susceptibility test and the actual cure rate of the applied antimicrobial treatment. Increasing evidence suggests that in vivo biofilm formation by Staph. aureus, which is not assessed in the antimicrobial susceptibility tests, is associated with this problem, resulting in disappointing cure rates, especially for infections of longer duration. Previous data obtained with a limited number of strains showed that the extended biofilm antimicrobial susceptibility (EBS) assay reveals differences between strains, which cannot be derived from a standard susceptibility test or from a 24-h biofilm susceptibility test. The objective of this study was to test a collection of Staph. aureus bovine mastitis strains in the EBS assay and to model the effect of antimicrobial exposure, duration of antimicrobial exposure, and genotype profile of the strains on antimicrobial susceptibility. With the results from a previous study with the same collection of strains, the effect of genotype represented by accessory gene regulator gene (agr-type), the presence of insertional sequence 257 (IS257), intercellular adhesion (ica), and the β-lactamase (blaZ) gene were entered as explanatory factors in a logistic regression model. The agr locus of Staph. aureus controls the expression of most of the virulence factors, represses the transcription of several cell wall-associated proteins, and activates several exoproteins during the post-exponential phase. The IS257 gene has been related to biofilm formation in vitro and was found earlier in 50% of the agr-type 2 strains. The ica gene cluster encodes for the production of an extracellular polysaccharide adhesin, termed

  6. In Vitro Susceptibilities of Candida dubliniensis Isolates Tested against the New Triazole and Echinocandin Antifungal Agents

    Science.gov (United States)

    Pfaller, M. A.; Messer, S. A.; Gee, S.; Joly, S.; Pujol, C.; Sullivan, D. J.; Coleman, D. C.; Soll, D. R.

    1999-01-01

    Candida dubliniensis is a newly recognized fungal pathogen causing mucosal disease in AIDS patients. Although preliminary studies indicate that most strains of C. dubliniensis are susceptible to established antifungal agents, fluconazole-resistant strains have been detected. Furthermore, fluconazole-resistant strains are easily derived in vitro, and these strains exhibit increased expression of multidrug resistance transporters, especially MDR1. Because of the potential for the development of resistant strains of C. dubliniensis, it is prudent to explore the in vitro activities of several of the newer triazole and echinocandin antifungals against isolates of C. dubliniensis. In this study we tested 71 isolates of C. dubliniensis against the triazoles BMS-207147, Sch 56592, and voriconazole and a representative of the echinocandin class of antifungal agents, MK-0991. We compared the activities of these agents with those of the established antifungal agents fluconazole, itraconazole, amphotericin B, and 5-fluorocytosine (5FC) by using National Committee for Clinical Laboratory Standards microdilution reference methods. Our findings indicate that the vast majority of clinical isolates of C. dubliniensis are highly susceptible to both new and established antifungal agents. Strains with decreased susceptibilities to fluconazole remained susceptible to the investigational agents as well as to amphotericin B and 5FC. The increased potencies of the new triazole and echinocandin antifungal agents may provide effective therapeutic options for the treatment of infections due to C. dubliniensis. PMID:9986880

  7. Development of a Laboratory-Scale Leaching Plant for Metal Extraction from Fly Ash by Thiobacillus Strains

    Science.gov (United States)

    Brombacher, Christoph; Bachofen, Reinhard; Brandl, Helmut

    1998-01-01

    Semicontinuous biohydrometallurgical processing of fly ash from municipal waste incineration was performed in a laboratory-scale leaching plant (LSLP) by using a mixed culture of Thiobacillus thiooxidans and Thiobacillus ferrooxidans. The LSLP consisted of three serially connected reaction vessels, reservoirs for a fly ash suspension and a bacterial stock culture, and a vacuum filter unit. The LSLP was operated with an ash concentration of 50 g liter−1, and the mean residence time was 6 days (2 days in each reaction vessel). The leaching efficiencies (expressed as percentages of the amounts applied) obtained for the economically most interesting metal, Zn, were up to 81%, and the leaching efficiencies for Al were up to 52%. Highly toxic Cd was completely solubilized (100%), and the leaching efficiencies for Cu, Ni, and Cr were 89, 64, and 12%, respectively. The role of T. ferrooxidans in metal mobilization was examined in a series of shake flask experiments. The release of copper present in the fly ash as chalcocite (Cu2S) or cuprite (Cu2O) was dependent on the metabolic activity of T. ferrooxidans, whereas other metals, such as Al, Cd, Cr, Ni, and Zn, were solubilized by biotically formed sulfuric acid. Chemical leaching with 5 N H2SO4 resulted in significantly increased solubilization only for Zn. The LSLP developed in this study is a promising first step toward a pilot plant with a high capacity to detoxify fly ash for reuse for construction purposes and economical recovery of valuable metals. PMID:16349536

  8. Antimicrobial susceptibility testing in India - A status survey

    Directory of Open Access Journals (Sweden)

    Sudha V

    2001-01-01

    Full Text Available Resistance to a variety of antimicrobial agents is emerging in bacterial pathogens throughout the world. Since the accuracy of the antimicrobial susceptibility data is associated with the performance standard of the test, strict adherence to the standard procedures is essential. The Kirby-Bauer disc diffusion susceptibility test, performed in accordance to NCCLS method gives reliable results and hence predicts clinical efficacy of the antibiotic tested. To assess the standard of performance of the antimicrobial susceptibility test, a survey was conducted by National Institute of Biologicals during 1999-2000. The findings indicated an urgent need of setting up a national quality control laboratory to provide the performance standards, reference Q.C. strains and quality antibiotic discs to ensure reproducible and reliable results.

  9. Antibiotic Susceptibility Patterns of Vibrio cholerae isolates

    Directory of Open Access Journals (Sweden)

    S D Shrestha

    2010-09-01

    Full Text Available INTRODUCTION: Cholera is one of the most common diarrhoeal diseases in Nepal. Etiological agent of cholera is Vibrio cholerae which removes essential body fluids, salts and vital nutrients, which are necessary for life causing dehydration and malnutrition. Emerging antimicrobial resistant is common. The aim of the present study was to determine the antibiotic susceptibility pattern of cholera patients in Nepal. METHODS: All the laboratory works were conducted in the bacteriology section of National Public Health Laboratory, Teku from March to September 2005. During this period a total of 340 stool samples from diarrhoeal patients were collected and processed according to the standard laboratory methods. Each patient suffering from diarrhoea was directly interviewed for his or her clinical history during sample collection. RESULTS: A total of 340 stool samples were processed and studied from both sex including all ages of patients. Among the processed sample 53 Vibrio cholerae cases were found. All isolated Vibrio cholerae O1 were El Tor, Inaba. All isolated (100% Vibrio cholerae O1 were sensitive to Ampicillin, Ciprofloxacin, Erythromycin and Tetracycline whereas all were resistant to Nalidixic acid and Cotrimoxazole. Only 15.1% cases were sensitive to Furazolidone whereas 84.9% were resistant. CONCLUSION: All V. cholerae strains isolated in this study were found resistant to Multi Drug Resistant (resistant to at least two antibiotics of different group. Ampicillin, Ciprofloxacin, Erythromycin and Tetracycline were found still more potent antibiotics against Vibrio cholerae isolated during the study. Keywords: antibiotics, susceptibility, Vibrio cholera.

  10. Increased tolerance towards serine obtained by adaptive laboratory evolution

    DEFF Research Database (Denmark)

    Mundhada, Hemanshu; Seoane, Jose Miguel; Koza, Anna

    2014-01-01

    by glyA), the conversion of serine to pyruvate (encoded by sdaA, sdaB and tdcG) was also deleted. As expected, the resulting strain turned out to be susceptible to even low concentrations of serine in the media. In order to improve the tolerance of the strain towards serine, adaptive laboratory evolution...... was implemented using a state of the art robotics platform. The strain was grown under inhibiting concentrations of serine in minimal media and was periodically transferred to new media during mid log phase. After achieving a desired increase in growth rate, the concentration was serine was gradually increased...

  11. Susceptibility of Aedes albopictus and Aedes aegypti to three imported Chikungunya virus strains, including the E1/226V variant in Taiwan

    OpenAIRE

    Chen, Tien-Huang; Jian, Shu-Wan; Wang, Chih-Yuan; Lin, Cheo; Wang, Pei-Feng; Su, Chien-Ling; Teng, Hwa-Jen; Shu, Pei-Yun; Wu, Ho-Sheng

    2015-01-01

    An E1/226V variant Chikungunya virus (CHIKV) efficiently transmitted by Aedes albopictus to humans poses a significant threat to public health for those areas with the presence of Aedes albopictus, including Taiwan. Methods: We infected three imported CHIKV isolates including the E1/226V variant with Ae. albopictus and Aedes aegypti in the laboratory to understand the disease risk. Viral RNA was measured by real time reverse transcription polymerase chain reaction. Results: The viral su...

  12. Oral Administration of the Probiotic Strain Escherichia coli Nissle 1917 Reduces Susceptibility to Neuroinflammation and Repairs Experimental Autoimmune Encephalomyelitis-Induced Intestinal Barrier Dysfunction

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    Thomas Secher

    2017-09-01

    Full Text Available Multiple sclerosis (MS is a chronic inflammatory disease of the central nervous system (CNS with an increasing incidence in developed countries. Recent reports suggest that modulation of the gut microbiota might be one promising therapy for MS. Here, we investigated whether the probiotic Escherichia coli strain Nissle 1917 (ECN could modulate the outcome of experimental autoimmune encephalomyelitis (EAE, a murine model of MS. We evidenced that daily oral treatment with ECN, but not with the archetypal K12 E. coli strain MG1655, reduced the severity of EAE induced by immunization with the MOG35–55 peptide. This beneficial effect was associated with a decreased secretion of inflammatory cytokines and an increased production of the anti-inflammatory cytokine IL-10 by autoreactive CD4 T cells, both in peripheral lymph nodes and CNS. Interestingly, ECN-treated mice exhibited increased numbers of MOG-specific CD4+ T cells in the periphery contrasting with severely reduced numbers in the CNS, suggesting that ECN might affect T cell migration from the periphery to the CNS through a modulation of their activation and/or differentiation. In addition, we demonstrated that EAE is associated with a profound defect in the intestinal barrier function and that treatment with ECN, but not with MG1655, repaired intestinal permeability dysfunction. Collectively, our data reveal that EAE induces a disruption of the intestinal homeostasis and that ECN protects from disease and restores the intestinal barrier function.

  13. High-level cefotaxime-resistant Proteus mirabilis strain isolated from ...

    African Journals Online (AJOL)

    Antimicrobial susceptibility was determined with the disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines and revealed that this strain was resistant to expanded-spectrum β-lactams. Analysis of P. mirabilis FS6449 by double-disk synergy test yielded a positive result suggesting the ...

  14. Acinetobacter baumannii strains isolated from patients in intensive care units in Goiânia, Brazil: Molecular and drug susceptibility profiles.

    Directory of Open Access Journals (Sweden)

    Suellen Rocha Araújo Castilho

    Full Text Available Resistance to antimicrobial agents is increasing worldwide and imposes significant life-threatening risks to several different populations, especially those in intensive care units (ICUs. Bacteria can quickly develop or acquire resistance to antimicrobial drugs, and combined with their intrinsic potential to cause disease in humans, these bacteria can become deadly. Among Gram-negative bacteria, Acinetobacter baumannii is notorious as a frequent opportunistic pathogen associated with critically ill patients, and understanding the genetic basis of A. baumannii resistance to beta-lactams among patients in ICUs will result in better protocols to prevent the development of resistance as well as improved treatment regimens. In this study, we assessed 1333 patients in five ICUs, 56 of whom developed A. baumannii infections. Most of the A. baumannii isolates were resistant to beta-lactam antimicrobial drugs, specifically, 3rd- and 4th-generation cephalosporins and carbapenems, and 91.1% of the isolates were multi-drug resistant (MDR. The most frequent OXA gene present was OXA-23 (55.1%, which is significantly associated with MDR strains. Most of the A. baumannii isolates (76.8% were capable of forming a biofilm. The antimicrobial drug classes that were effective against most of these isolates were polymyxins and tigecycline. The molecular profile of the isolates allowed detection of 12 different clusters comprising 2 to 8 isolates each. In conclusion, our data indicate a high incidence of resistance to carbapenems as well as MDR strains among the observed A. baumannii isolates, most of which exhibited a high prevalence of OXA-23 gene expression. Only a few selective drugs were effective, reinforcing the notion that bacterial resistance is an emerging problem that should be prioritized in every healthcare facility.

  15. Effects of crude extracts of a saxitoxin-producer strain of the cyanobacterium Cylindrospermopsis raciborskii on the swimming behavior of wild and laboratory reared guppy Poecilia vivipara.

    Science.gov (United States)

    Lopes, Karina C; Ferrão-Filho, Aloysio da S; Dos Santos, Everton G N; Cunha, Rodolfo A; Santos, Cláudia P

    2017-04-01

    The cyanobacterium Cylindrospermopsis raciborskii is an invasive species in water supply reservoirs worldwide, which can produces cylindrospermopsins and saxitoxins. In the wild, guppy (Poecilia vivipara) can be exposed to cyanotoxins, but those born and reared in laboratory are free of this contact. The aim of this paper was to comparatively measure the locomotor activity of 'wild' and 'lab' P. vivipara before and after exposure to crude extracts of two different cultures of C. raciborskii (CYRF-01), a saxitoxin-procucer strain. The movement of each fish was recorded using an image monitoring system (Videomex V(®)) before and after 48 h exposure to cyanobacterial extracts. Each experiment was performed during 4 h, with 1 h acclimation and 3 h recording period of the parameters Distance performed (DP), Swimming time (SwT), Stereotypic time (StT), Resting time (RT) and Average speed (AS). The quantification of saxitoxin in the solutions was performed by the enzyme-linked immunosorbent assay (ELISA). The weight or the total length did not influence the locomotor activity of fish in any of the experiments. The saxitoxin value was similar for both cultures (Culture 1: 7.3 μg L(-1) and Culture 2: 8.6 μg L(-1)). However, in experiments with Culture 1 an increased activity in most parameters was observed, while in Culture 2, a decreased activity was observed only in 'lab' fish. Wild fish was less affected, showing higher resistance to both cyanobacterial crude extracts. This study showed that different cultures of the same strain of C. raciborskii and with similar contents of saxitoxin are able to change the locomotor activity of P. vivipara, contributing to the validation of the use of behavioral parameters to the evaluation of sublethal effects of toxic cyanobacteria on fish. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Prion protein gene variability in Spanish goats. Inference through susceptibility to classical scrapie strains and pathogenic distribution of peripheral PrP(sc..

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    Cristina Acín

    Full Text Available Classical scrapie is a neurological disorder of the central nervous system (CNS characterized by the accumulation of an abnormal, partially protease resistant prion protein (PrP(sc in the CNS and in some peripheral tissues in domestic small ruminants. Whereas the pathological changes and genetic susceptibility of ovine scrapie are well known, caprine scrapie has been less well studied. We report here a pathological study of 13 scrapie-affected goats diagnosed in Spain during the last 9 years. We used immunohistochemical and biochemical techniques to discriminate between classical and atypical scrapie and bovine spongiform encephalopathy (BSE. All the animals displayed PrP(sc distribution patterns and western blot characteristics compatible with classical scrapie. In addition, we determined the complete open reading frame sequence of the PRNP in these scrapie-affected animals. The polymorphisms observed were compared with those of the herd mates (n = 665 and with the frequencies of healthy herds (n = 581 of native Spanish goats (Retinta, Pirenaica and Moncaina and other worldwide breeds reared in Spain (Saanen, Alpine and crossbreed. In total, sixteen polymorphic sites were identified, including the known amino acid substitutions at codons G37V, G127S, M137I, I142M, H143R, R151H, R154H, R211Q, Q222K, G232W, and P240S, and new polymorphisms at codons G74D, M112T, R139S, L141F and Q215R. In addition, the known 42, 138 and 179 silent mutations were detected, and one new one is reported at codon 122. The genetic differences observed in the population studied have been attributed to breed and most of the novel polymorphic codons show frequencies lower than 5%. This work provides the first basis of polymorphic distribution of PRNP in native and worldwide goat breeds reared in Spain.

  17. Susceptibility and detoxifying enzyme activity in two spider mite species (Acari: Tetranychidae) after selection with three insecticides.

    Science.gov (United States)

    Yang, Xuemei; Buschman, Lawrent L; Zhu, Kun Yan; Margolies, David C

    2002-04-01

    Changes in the susceptibility and detoxifying enzyme activity were measured in laboratory strains of Banks grass mite, Oligonychus pratensis (Banks), and twospotted spider mite, Tetranychus urticae Koch, that were repeatedly exposed to three insecticides. Three strains of each mite species were exposed to one of two pyrethroids, bifenthrin, and lambda-cyhalothrin, or an organophosphate, dimethoate, for 10 selection cycles at the LC60 for each insecticide. A reference or nonselected strain of each mite species was not exposed to insecticides. After 10 cycles of exposure, susceptibility to the corresponding insecticides, bifenthrin, lambda-cyhalothrin, and dimethoate, decreased 4.5-, 5.9-, and 289.2-fold, respectively, relative to the reference strain in the respective O. pratensis strains, and 14.8-, 5.7-, and 104.7-fold, respectively, relative to the reference strain in the respective T. urticae strains. In the bifenthrin-exposed O. pratensis strain, there was a 88.9-fold cross-resistance to dimethoate. In the dimethoate-exposed T. urticae strain, there was a 15.9-fold cross-resistance to bifenthrin. These results suggest that there may be cross-resistance between dimethoate and bifenthrin. The reduced susceptibility to dimethoate remained stable for three months in the absence of selection pressure in both mites. The decrease in susceptibility in the O. pratensis strains exposed to bifenthrin, lambda-cyhalothrin, and dimethoate was associated with a 4.7-, 3.0-, and 3.6-fold increase in general esterase activity, respectively. The decrease in susceptibility in the T. urticae strains exposed to bifenthrin and lambda-cyhalothrin was associated with a 1.3- and 1.1-fold increase in general esterase activity, respectively. The mean general esterase activity was significantly higher in the pyrethroid-exposed O. pratensis and T. urticae strains than in the nonselected strain. There was no significant increase in esterase activity in the dimethoate-exposed T. urticae

  18. 'Prevalence and antimicrobial susceptibility of Listeria monocytogenes and methicillin-resistant Staphylococcus aureus strains from raw meat and meat products in Zaria, Nigeria.

    Science.gov (United States)

    Ndahi, M D; Kwaga, J K P; Bello, M; Kabir, J; Umoh, V J; Yakubu, S E; Nok, A J

    2014-03-01

    The bacterial genera Listeria and Staphylococcus have been frequently isolated from food products and are responsible for a number of animal and human diseases. The aim of the study was to simultaneously isolate and characterize L. monocytogenes and Staphylococcus species from 300 samples of raw meat and meat products, to determine the susceptibility of the organisms to commonly used antimicrobial agents and to determine the presence of haemolysin A (hyl) virulence gene in L. monocytogenes and staphylococcal cassette chromosome mecA (SCCmec) gene in the Staph. aureus isolates using PCR. Of the 85 Listeria isolates tested, 12 L. monocytogenes were identified and tested for their sensitivity to 14 antimicrobial agents. All the 12 isolates (100%) were resistant to nine antimicrobial agents, but however sensitive to gentamicin. Only one isolate was found to harbour the hylA gene. Twenty-nine isolates were confirmed as Staph. aureus by the Microbact 12S identification system and were all presumptively identified as methicillin-resistant Staph. aureus species using oxacillin-resistant Staph. aureus basal medium (ORSAB). The 29 Staph. aureus isolates were tested for their sensitivity to 16 antimicrobial agents, and 11 were resistant to methicillin. None of the 11 Staph. aureus isolates harboured the methicillin resistance, mecA gene. Listeria monocytogenes and Staphylococcus aureus are important agents of foodborne diseases. Occurrence of these infectious agents was established in meat and meat products in Zaria, Nigeria. Majority of isolates obtained from this study, displayed multidrug resistance to commonly used antimicrobial agents, including methicillin resistance among the Staph. aureus isolates. The potential virulence of L. monocytogenes found in ready-to-eat food was documented by the carriage of hly A gene by one of the isolates. A different mechanism of methicillin resistance or different homologue of mec A gene may be circulating among Nigerian

  19. Increased sensitivity to CD4 binding site-directed neutralization following in vitro propagation on primary lymphocytes of a neutralization-resistant human immunodeficiency virus IIIB strain isolated from an accidentally infected laboratory worker

    NARCIS (Netherlands)

    Beaumont, Tim; Quakkelaar, Esther; van Nuenen, Ad; Pantophlet, Ralph; Schuitemaker, Hanneke

    2004-01-01

    We previously described the adaptation of the neutralization-sensitive human immunodeficiency virus type 1 (HIV-1) strain IIIB to a neutralization-resistant phenotype in an accidentally infected laboratory worker. During long-term propagation of this resistant isolate, designated FF3346, on primary

  20. Antimicrobial susceptibility of bacteria, isolated from patients treated at Jesenice General hospital in the period between 2004 and 2006

    Directory of Open Access Journals (Sweden)

    Helena Ribič

    2007-11-01

    Full Text Available Background: Antimicrobial resistance of bacteria is still one of the mayor problems in medicine. In the year 2006, microbiologists of the Institute of Public Health Kranj together with clinicians and pharmacist of Jesenice General Hospital prepared the programm of antimicrobial resistance surveillance of patients treated in the hospital. Some of the results are presented in this article.Methods: In the retrospective study, bacterial strains, isolated from different samples were analysed. The strains were isolated and studied during the routine work of microbiology laboratory of IPH Kranj in the period between 2004 and 2006.Results: The most frequently isolated bacteria from haemocultures was Escherichia coli (35.4 %. In the years 2004 and 2006, susceptibility of strains for ciprofloxacin was 95.7 % and 97.2 %, for parenteral cefuroxime (95.7 % and 94.4 %, for cefotaxime and gentamicin in both years 100 %. Susceptibili