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

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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.

In Vitro Susceptibility Test of Different Clinical Isolates against Ceftriaxone

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Syed Hakim Masood

2010-06-01

Full Text Available Objectives: Because of the prevailing penicillin resistance in microorganisms, broad spectrum cephalosporins are used empirically specially in developing countries. The aim of this study is to determine the susceptibility pattern of different gram positive and gram negative pathogens against third generation cephalosporin-ceftriaxone to explore the existing effectiveness of this antibiotic.Methods: 180 clinical isolates of different gram positive and gram negative pathogens including P.mirabilis, S. typhi P.aeruginosa, E. coli, S. aureus and Klebsiella were collected from blood and urine samples of in-patients. 30 isolates of all species were tested against each of six brands of ceftriaxone using in vitro sensitivity tests by disc diffusion method (NCCLS criteria. The susceptibility limit was ≥21 mm zone of inhibition, while moderately susceptible was considered at 20-14 mm, and those isolates which showed >13 mm or no zone of inhibition were resistant to this antibacterial drug.Results: Ceftriaxone was found most effective against S. aureus. While 96.1% of the isolates showed susceptibility towards ceftriaxone, followed by E. coli (95%, P. aeruginosa (92.7%, K. pneumonia (89.4% and S. typhi (87.2%. P. mirabilis showed lowest susceptibility amongst all the test organisms (83.8%.Conclusion: Ceftriaxone can be used as a drug of choice in infections caused by S. aureus, E. coli, P. aurigenosa, K. pneumonia and S. typhi. However, it should be used with other antimicrobial agents in order to increase its effectiveness against P. mirabilis.

Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis : Its utility in resource poor settings

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Poojary A

2006-01-01

Full Text Available Purpose: To compare the rapid colorimetric nitrate reductase based antibiotic susceptibility (CONRAS test performed on Mycobacterium tuberculosis isolates with the conventional method i.e., the proportion method. Methods: One hundred clinical isolates of M. tuberculosis were tested for susceptibility to isoniazid (INH and rifampicin (RIF by the conventional proportion method and CONRAS in Middlebrook 7H9 liquid medium enriched with growth supplements (MB7H9S. Results: The performance of the CONRAS test was evaluated using proportion method as the gold standard. The sensitivity (ability to detect true drug resistance and specificity (ability to detect true drug susceptibility of the CONRAS test to INH was 93.75 and 98.52% and for RIF it was 96.10 and 100% respectively. The mean time for reporting was 6.3 days and the test showed excellent reproducibility. The kappa (k value for INH was 0.92 and for RIF was 0.99, indicating excellent agreement between the two methods. Conclusions: CONRAS test is a rapid and reliable method of drug susceptibility for M. tuberculosis.

Flow cytometry susceptibility testing for conventional antifungal drugs and Comparison with the NCCLS Broth Macrodilution Test

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M.J. Najafzadeh

2009-08-01

Full Text Available Introduction: During the last decade, the incidence of fungal infection has been increased in many countries. Because of the advent of resistant to antifungal agents, determination of an efficient strategic plan for treatment of fungal disease is an important issue in clinical mycology. Many methods have been introduced and developed for determination of invitro susceptibility tests. During the recent years, flow cytometry has developed to solving the problem and many papers have documented the usefulness of this technique. Materials and methods: As the first step, the invitro susceptibility of standard PTCC (Persian Type of Culture Collection strain and some clinical isolates of Candida consisting of Candida albicans, C. dubliniensis, C. glabrata, C. kefyer and C. parapsilosis were evaluated by macrodilution broth method according to NCCLS (National Committee for Clinical Laboratory Standards guidelines and flow cytometry susceptibility test. Results:  The data indicated that macro dilution broth methods and flow cytometry have the same results in determination of MIC (Minimum Inhibitory Concentration for amphotericin B, clotrimazole, fluconazole, ketoconazole and miconazole in C. albicans PTCC 5027 as well as clinical Candida isolates, such as C.albicans, C.dubliniensis, C.glabrata C.kefyr, and C.parapsilosis. Discussion: Comparing the results obtained by macrodilution broth and flow cytometry methods revealed that flow cytometry was faster. It is suggested that flow cytometry susceptibility test can be used as a powerful tool for determination of MIC and administration of the best antifungal drug in treatment of patients with Candida infections.

Evaluation of rapid radiometric method for drug susceptibility testing of Mycobacterium tuberculosis

International Nuclear Information System (INIS)

Siddiqi, S.H.; Libonati, J.P.; Middlebrook, G.

1981-01-01

A total of 106 isolates of Mycobacterium tuberculosis were tested for drug susceptibility by the conventional 7H11 plate method and by a new rapid radiometric method using special 7H12 liquid medium with 14 C-labeled substrate. Results obtained by the two methods were compared for rapidity, sensitivity, and specificity of the new test method. There was 98% overall agreement between the results obtained by the two methods. Of a total of 424 drug tests, only 8 drug results did not agree, mostly in the case of streptomycin. This new procedure was found to be rapid, with 87% of the tests results reportable within 4 days and 98% reportable within 5 days as compared to the usual 3 weeks required with the conventional indirect susceptibility test method. The results of this preliminary study indicate that the rapid radiometric method seems to have the potential for routine laboratory use and merits further investigations

Susceptibility testing of fish cell lines for virus isolation

DEFF Research Database (Denmark)

Ariel, Ellen; Skall, Helle Frank; Olesen, Niels Jørgen

2009-01-01

and laboratories, but also between lineages of the same cell line. To minimise the occurrence of false negatives in a cell culture based surveillance system, we have investigated methods, to select cell lineages that are relatively superior in their susceptibility to a panel of virus isolates. The procedures...... cell lineages, we increased the number of isolates of each virus, propagated stocks in a given cell line and tested all lineages of that line in use in the laboratory. Testing of relative cell line susceptibility between laboratories is carried out annually via the Inter-laboratory Proficiency Test...... sensitivity for surveillance purposes within a cell line and between laboratories.In terms of economic and practical considerations as well as attempting to approach a realistic test system, we suggest the optimal procedure for susceptibility testing of fish cell lines for virus isolation to be a combination...

Using Reduced Inoculum Densities of Mycobacterium tuberculosis in MGIT Pyrazinamide Susceptibility Testing to Prevent False-Resistant Results and Improve Accuracy: A Multicenter Evaluation

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Glenn P. Morlock

2017-01-01

Full Text Available The primary platform used for pyrazinamide (PZA susceptibility testing of Mycobacterium tuberculosis is the MGIT culture system (Becton Dickinson. Since false-resistant results have been associated with the use of this system, we conducted a multicenter evaluation to determine the effect of using a reduced cell density inoculum on the rate of false resistance. Two reduced inoculum densities were compared with that prescribed by the manufacturer (designated as “BD” method. The reduced inoculum methods (designated as “A” and “C” were identical to the manufacturer’s protocol in all aspects with the exception of the cell density of the inoculum. Twenty genetically and phenotypically characterized M. tuberculosis isolates were tested in duplicate by ten independent laboratories using the three inoculum methods. False-resistant results declined from 21.1% using the standard “BD” method to 5.7% using the intermediate (“A” inoculum and further declined to 2.8% using the most dilute (“C” inoculum method. The percentages of the resistant results that were false-resistant declined from 55.2% for the “BD” test to 28.8% and 16.0% for the “A” and “C” tests, respectively. These results represent compelling evidence that the occurrence of false-resistant MGIT PZA susceptibility test results can be mitigated through the use of reduced inoculum densities.

Comparison of agar dilution and antibiotic gradient strip test with broth microdilution for susceptibility testing of swine Brachyspira species.

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Mirajkar, Nandita S; Gebhart, Connie J

2016-03-01

Production-limiting diseases in swine caused by Brachyspira are characterized by mucohemorrhagic diarrhea (B. hyodysenteriae and "B. hampsonii") or mild colitis (B. pilosicoli), while B. murdochii is often isolated from healthy pigs. Emergence of novel pathogenic Brachyspira species and strains with reduced susceptibility to commonly used antimicrobials has reinforced the need for standardized susceptibility testing. Two methods are currently used for Brachyspira susceptibility testing: agar dilution (AD) and broth microdilution (BMD). However, these tests have primarily been used for B. hyodysenteriae and rarely for B. pilosicoli. Information on the use of commercial susceptibility testing products such as antibiotic gradient strips is lacking. Our main objective was to validate and compare the susceptibility results, measured as the minimum inhibitory concentration (MIC), of 6 antimicrobials for 4 Brachyspira species (B. hyodysenteriae, "B. hampsonii", B. pilosicoli, and B. murdochii) by BMD and AD (tiamulin, valnemulin, lincomycin, tylosin, and carbadox) or antibiotic gradient strip (doxycycline) methods. In general, the results of a high percentage of all 4 Brachyspira species differed by ±1 log2 dilution or less by BMD and AD for tiamulin, valnemulin, lincomycin, and tylosin, and by BMD and antibiotic gradient strip for doxycycline. The carbadox MICs obtained by BMD were 1-5 doubling dilutions different than those obtained by AD. BMD for Brachyspira was quicker to perform with less ambiguous interpretation of results when compared with AD and antibiotic gradient strip methods, and the results confirm the utility of BMD in routine diagnostics. © 2016 The Author(s).

Results of Use of WHO Global Salm-Surv External Quality Assurance System for Antimicrobial Susceptibility Testing of Salmonella Isolates from 2000 to 2007

DEFF Research Database (Denmark)

Hendriksen, Rene S.; Seyfarth, Anne Mette; Jensen, Arne Bent

2009-01-01

laboratories in 102 countries participated in at least one EQAS iteration. A large number of laboratories reported results for the E. coli ATCC 25922 reference strain which were outside the quality control ranges. Critical deviations for susceptibility testing of the Salmonella isolates varied from 4% in 2000......An international External Quality Assurance System (EQAS) for antimicrobial susceptibility testing of Salmonella was initiated in 2000 by the World Health Organization (WHO) Global Salm-Surv in order to enhance the capacities of national reference laboratories to obtain reliable data....... In particular, further training and dissemination of information on quality control, appropriate interpretive criteria (breakpoints), and harmonization of the methodology worldwide through WHO Global Salm-Surv and other programs will contribute to the generation of comparable and reliable antimicrobial...

Agar dilution method for susceptibility testing of Neisseria gonorrhoeae

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Marta C de Castillo

1996-12-01

Full Text Available The antibiotic susceptibilities of Neisseria gonorrhoeae isolates obtained from patients attending a clinic for sexually transmitted diseases in Tucumán, Argentina, were determined by the agar dilution method (MIC. 3.5% of the isolates produced ²-lactamase. A total of 96.5% of ²-lactamase negative isolates tested were susceptible to penicillin (MIC < 2 µgml-1; 14.03% of the tested isolates were resistant to tetracycline (MIC < 2 µgml-1, and 98% of the tested isolates were susceptible to spectinomycin (MIC < 64 µgml-1. The MICs for 95% of the isolates, tested for other drugs were: < 2 µgml-1 for cefoxitin, < 0.06 µgml-1 for cefotaxime, < 0.25 µgml-1 for norfloxacin, < 10 µgml-1 for cephaloridine, < 10 µgml-1 for cephalexin, and < 50 µgml-1 for kanamycin. Antibiotic resistance among N. gonorrhoeae isolates from Tucumán, Argentina, appeared to be primarily limited to penicillin and tetracycline, which has been a general use against gonorrhoeae in Tucumán since 1960. Periodic monitoring of the underlying susceptibility profiles of the N. gonorrhoeae strains prevalent in areas of frequent transmission may provide clues regarding treatment options and emerging of drug resistance.

Laboratory Diagnosis and Susceptibility Testing for Mycobacterium tuberculosis.

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Procop, Gary W

2016-12-01

The laboratory, which utilizes some of the most sophisticated and rapidly changing technologies, plays a critical role in the diagnosis of tuberculosis. Some of these tools are being employed in resource-challenged countries for the rapid detection and characterization of Mycobacterium tuberculosis. Foremost, the laboratory defines appropriate specimen criteria for optimal test performance. The direct detection of mycobacteria in the clinical specimen, predominantly done by acid-fast staining, may eventually be replaced by rapid-cycle PCR. The widespread use of the Xpert MTB/RIF (Cepheid) assay, which detects both M. tuberculosis and key genetic determinants of rifampin resistance, is important for the early detection of multidrug-resistant strains. Culture, using both broth and solid media, remains the standard for establishing the laboratory-based diagnosis of tuberculosis. Cultured isolates are identified far less commonly by traditional biochemical profiling and more commonly by molecular methods, such as DNA probes and broad-range PCR with DNA sequencing. Non-nucleic acid-based methods of identification, such as high-performance liquid chromatography and, more recently, matrix-assisted laser desorption/ionization-time of flight mass spectrometry, may also be used for identification. Cultured isolates of M. tuberculosis should be submitted for susceptibility testing according to standard guidelines. The use of broth-based susceptibility testing is recommended to significantly decrease the time to result. Cultured isolates may also be submitted for strain typing for epidemiologic purposes. The use of massive parallel sequencing, also known as next-generation sequencing, promises to continue to this molecular revolution in mycobacteriology, as whole-genome sequencing provides identification, susceptibility, and typing information simultaneously.

Perceived susceptibility and self-protective behavior: a field experiment to encourage home radon testing

International Nuclear Information System (INIS)

Weinstein, N.D.; Sandman, P.M.; Roberts, N.E.

1991-01-01

Tested in a field experiment (N = 647) the hypothesis that perceptions of personal susceptibility are important in decisions to test one's home for radioactive radon gas. Experimental group subjects received a personal telephone call to tell them they lived in a high-risk area and a personal letter to reinforce the telephone message. After the intervention, experimental subjects were significantly more likely than minimal-treatment subjects to acknowledge the possibility of high radon levels in their homes. Perceptions of susceptibility and illness severity were significantly correlated with orders of radon test kits and with testing intentions. Nevertheless, there were no differences between groups in test orders or intentions. Results are discussed in terms of the difficulty of getting people to acknowledge susceptibility and the factors other than risk perceptions that influence self-protective behavior

Etest Cannot Be Recommended for In Vitro Susceptibility Testing of Mucorales

OpenAIRE

Caramalho, Rita; Maurer, Elisabeth; Binder, Ulrike; Araújo, Ricardo; Dolatabadi, Somayeh; Lass-Flörl, Cornelia; Lackner, Michaela

2015-01-01

Amphotericin B and posaconazole susceptibility patterns were determined for the most prevalent Mucorales, following EUCAST (European Committee on Antimicrobial Susceptibility Testing) broth microdilution guidelines. In parallel, Etest was performed and evaluated against EUCAST. The overall agreement of MICs gained with Etest and EUCAST was 75.1%; therefore, Etest cannot be recommended for antifungal susceptibility testing of Mucorales. Amphotericin B was the most active drug against Mucorales...

Individual Differences in Digit Span, Susceptibility to Proactive Interference, and Aptitude/Achievement Test Scores.

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Dempster, Frank N.; Cooney, John B.

1982-01-01

Individual differences in digit span, susceptibility to proactive interference, and various aptitude/achievement test scores were investigated in two experiments with college students. Results indicated that digit span was strongly correlated with aptitude/achievement scores, but did not indicate that susceptibility to proactive interference…

Reliability of provocative tests of motion sickness susceptibility

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Calkins, D. S.; Reschke, M. F.; Kennedy, R. S.; Dunlop, W. P.

1987-01-01

Test-retest reliability values were derived from motion sickness susceptibility scores obtained from two successive exposures to each of three tests: (1) Coriolis sickness sensitivity test; (2) staircase velocity movement test; and (3) parabolic flight static chair test. The reliability of the three tests ranged from 0.70 to 0.88. Normalizing values from predictors with skewed distributions improved the reliability.

Selection of media for antimicrobial susceptibility testing of fish pathogenic bacteria

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Dalsgaard, Inger

2001-01-01

3, Diagnostic Sensitivity Test Agar) have been used in addition to media (Brain Heart Infusion Agar, Heart Infusion Agar, Columbia Blood Agar) normally utilized for cultivating fastidious bacteria. When testing marine pathogens, sodium chloride or seawater has been included in the media. Media...... pattern in fish pathogenic bacteria. The American guideline from The National Committee for Clinical Laboratory Standards (NCCLS) recommends Mueller-Hinton Agar for susceptibility testing of human pathogens and this validated medium appears to be adequate for the rapidly growing fish pathogens. Following......The available data concerning antimicrobial susceptibility testing of fish pathogens showed that there is no consensus to the basal medium currently being employed. Different media recommended for susceptibility testing of human pathogens (Mueller-Hinton Agar, Tryptone Soya Agar, Antibiotic Medium...

Selection of media for antimicrobial susceptibility testing of fish pathogenic bacteria

DEFF Research Database (Denmark)

Dalsgaard, Inger

2001-01-01

The available data concerning antimicrobial susceptibility testing of fish pathogens showed that there is no consensus to the basal medium currently being employed. Different media recommended for susceptibility testing of human pathogens (Mueller-Hinton Agar, Tryptone Soya Agar, Antibiotic Medium...... 3, Diagnostic Sensitivity Test Agar) have been used in addition to media (Brain Heart Infusion Agar, Heart Infusion Agar, Columbia Blood Agar) normally utilized for cultivating fastidious bacteria. When testing marine pathogens, sodium chloride or seawater has been included in the media. Media...... normally used for cultivation of pathogens with specific growth requirements like Flavobacterium species and Renibacterium salmoninarum have been used for susceptibility testing. The Mueller-Hinton Agar and different modifications of this medium was used most frequently in published studies on resistant...

Improved method for testing susceptibility of Mycobacterium tuberculosis to pyrazinamide.

OpenAIRE

Butler, W R; Kilburn, J O

1982-01-01

The acid medium required to test susceptibility of Mycobacterium tuberculosis to pyrazinamide (PZA) is a major problem in obtaining reliable test results. Satisfactory growth is usually obtained on Middlebrook and Cohn 7H10 medium at pH 5.5 if albumin-dextrose-catalase (ADC) supplement rather than oleic acid-albumin-dextrose-catalase is used; however, some lots of ADC supplement still fail to support growth at this low pH. A rapid turbidimetric test was developed to determine the growth-suppo...

Comparing the disk-diffusion and agar dilution tests for Neisseria gonorrhoeae antimicrobial susceptibility testing

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Hsi Liu

2016-11-01

Full Text Available Abstract Background We assessed the validity of testing for antimicrobial susceptibility of clinical and mutant Neisseria gonorrhoeae (GC isolates by disk diffusion in comparison to agar dilution, and Etest® (bioMerieux, France, respectively, for three third generation extended spectrum cephalosporins (ESC: ceftriaxone (CRO, cefixime (CFX, and cefpodoxime (CPD. Methods One hundred and five clinical isolates and ten laboratory-mutants were tested following Clinical Laboratory Standard Institute (CLSI and manufacturer’s standards for each of the three methods. The measured diameters by the disk diffusion method were tested for correlation with the MIC values by agar dilution. In addition, comparisons with the Etest® were made. Categorical results for concordance, based on standard CLSI cutoffs, between the disk diffusion and the other two methods, respectively, were tested using the Chi-square statistics. Reproducibility was tested for CFX across a 6-month interval by repeated disk tests. Results Across all 115 specimens, the disk diffusion tests produced good categorical agreements, exhibiting concordance of 93.1%, 92.1%, and 90.4% with agar dilution and 93.0%, 92.1%, and 90.4% with Etest®, for CRO, CFX, and CPD, respectively. Pearson correlations between disk-diffusion diameters and agar dilution MIC’s were -0.59, -0.67, and -0.81 for CRO, CFX, and CPD, respectively. The correlations between disk diffusion and Etest® were -0.58, -0.73, and -0.49. Pearson correlation between the CFX disk readings over a 6-month interval was 91%. Conclusions Disk diffusion tests remain to be a useful, reliable and fast screening method for qualitative antimicrobial susceptibility testing for ceftriaxone, cefixime, and cefpodoxime.

Etest cannot be recommended for in vitro susceptibility testing of mucorales.

Science.gov (United States)

Caramalho, Rita; Maurer, Elisabeth; Binder, Ulrike; Araújo, Ricardo; Dolatabadi, Somayeh; Lass-Flörl, Cornelia; Lackner, Michaela

2015-01-01

Amphotericin B and posaconazole susceptibility patterns were determined for the most prevalent Mucorales, following EUCAST (European Committee on Antimicrobial Susceptibility Testing) broth microdilution guidelines. In parallel, Etest was performed and evaluated against EUCAST. The overall agreement of MICs gained with Etest and EUCAST was 75.1%; therefore, Etest cannot be recommended for antifungal susceptibility testing of Mucorales. Amphotericin B was the most active drug against Mucorales species in vitro, while the activities of posaconazole were more restricted. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Evaluation of the routine antimicrobial susceptibility testing results of clinically significant anaerobic bacteria in a Slovenian tertiary-care hospital in 2015.

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Jeverica, Samo; Kolenc, Urša; Mueller-Premru, Manica; Papst, Lea

2017-10-01

The aim of our study was to determined antimicrobial susceptibility profiles of 2673 clinically significant anaerobic bacteria belonging to the major genera, isolated in 2015 in a large tertiary-care hospital in Slovenia. The species identification was performed by MALDI-TOF mass spectrometry. Antimicrobial susceptibility was determined immediately at the isolation of the strains against: penicillin, co-amoxiclav, imipenem, clindamycin and metronidazole, using gradient diffusion methodology and EUCAST breakpoints. The most frequent anaerobes were Bacteroides fragilis group with 31% (n = 817), Gram positive anaerobic cocci (GPACs) with 22% (n = 589), Prevotella with 14% (n = 313) and Propionibacterium with 8% (n = 225). Metronidazole has retained full activity (100%) against all groups of anaerobic bacteria intrinsically susceptible to it. Co-amoxiclav and imipenem were active against most tested anaerobes with zero or low resistance rates. However, observed resistance to co-amoxiclav (8%) and imipenem (1%) is worrying especially among B. fragilis group isolates. High overall resistance (23%) to clindamycin was detected in our study and was highest among the genera Prevotella, Bacteroides, Parabacteroides, GPACs and Clostridium. Routine testing of antimicrobial susceptibility of clinically relevant anaerobic bacteria is feasible and provides good surveillance data. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Microfluidics for Antibiotic Susceptibility and Toxicity Testing

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Jing Dai

2016-10-01

Full Text Available The recent emergence of antimicrobial resistance has become a major concern for worldwide policy makers as very few new antibiotics have been developed in the last twenty-five years. To prevent the death of millions of people worldwide, there is an urgent need for a cheap, fast and accurate set of tools and techniques that can help to discover and develop new antimicrobial drugs. In the past decade, microfluidic platforms have emerged as potential systems for conducting pharmacological studies. Recent studies have demonstrated that microfluidic platforms can perform rapid antibiotic susceptibility tests to evaluate antimicrobial drugs’ efficacy. In addition, the development of cell-on-a-chip and organ-on-a-chip platforms have enabled the early drug testing, providing more accurate insights into conventional cell cultures on the drug pharmacokinetics and toxicity, at the early and cheaper stage of drug development, i.e., prior to animal and human testing. In this review, we focus on the recent developments of microfluidic platforms for rapid antibiotics susceptibility testing, investigating bacterial persistence and non-growing but metabolically active (NGMA bacteria, evaluating antibiotic effectiveness on biofilms and combinatorial effect of antibiotics, as well as microfluidic platforms that can be used for in vitro antibiotic toxicity testing.

Comparison of E-test with other conventional susceptibility testing methods for ciprofloxacin and gentamicin against gram negative enteric bacilli.

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Ogbolu, D O; Terry-Alli, O A; Daini, O A; Olabiyi, F A; Igharo, E A

2012-06-01

Increasing antibiotic resistance in Gram negative bacteria has led to the need for a faster and reliable method for determining antimicrobial susceptibility testing. In a resource poor setting like ours, it's also important to look for methods that will be clinically and economically beneficial to the patient. This study was aimed at evaluating the Epsilometer test (E-test) and conventional methods for determining antimicrobial susceptibility of isolates of Gram-negative enteric bacteria to ciprofloxacin and gentamicin. Disc diffusion, E-test, broth dilution and agar dilution methods were performed on 54 bacterial isolates. Using the E-test, 88.9% of bacterial isolates were resistant to ciprofloxacin, 92.6% were resistant using broth microdilution, 96.3% were resistant using agar dilution and 72.2% were resistant using disc diffusion. Minimum inhibitory concentration (MIC50) of isolates for gentamicin showed significant difference for all the techniques (p 0.05). Both E-test and broth dilution methods showed high levels of agreement (p > 0.05), there were low levels of agreement between E-test and agar dilution method (p < 0.05), especially at MIC50. The E-test can therefore be considered a reliable method to determine antimicrobial susceptibility testing and it gives results which are at least as accurate as those obtained by the broth dilution method.

Antifungal susceptibility testing of vaginal candida isolates: the broth microdilution method

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Mahmoudi Rad M

2010-02-01

Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: Vulvovaginal candidiasis is a common mucosal infection among immunocompetent, healthy women, and is caused by opportunistic yeasts that belong to genus Candida. In this study, we isolated and identified the Candida species in the vagina of patients who admitted in Gynecology Department of Mahdieh Hospital in Tehran, Iran to evaluate the in vitro activities of fluconazole, miconazole, itraconazole and flucytosine against 191 clinical Candida isolates by the NCCLS microdilution method."n"nMethods: 191 Candida were isolated from vaginal secretions and identified with conventional mycological methods in the diagnosis of Candida species. The identity of all strains was confirmed genotypically by multiplex PCR. In vitro susceptibility testing of vaginal Candida isolates was performed by the NCCLS broth microdilution method. The results were read at 48 h."n"nResults: Most C. albicans isolates (>90% were sensitive in vitro to the antifungal agents tested. Most C. glabrata isolates showed sensitivity to miconazole and then flucytosine while they were more resistant to Itraconazole and fluconazole. Many isolates of C. tropicalis were susceptible to miconazole and then fluconazole. They showed a little resistance to

Nonlinear susceptibility: A direct test of the quadrupolar Kondo effect in UBe13

International Nuclear Information System (INIS)

Ramirez, A.P.; Chandra, P.; Coleman, P.; Fisk, Z.; Smith, J.L.; Ott, H.R.

1994-01-01

We present the nonlinear susceptibility as a direct test of the quadrupolar Kondo scenario for heavy fermion behavior, and apply it to the case of cubic crystal-field symmetry. Within a single-ion model we compute the nonlinear susceptibility resulting from low-lying Γ 3 (5f 2 ) and Kramers (5f 3 ) doublets. We find that nonlinear susceptibility measurements on single-crystal UBe 13 are inconsistent with a quadrupolar (5f 2 ) ground state of the uranium ion; the experimental data indicate that the low-lying magnetic excitations of UBe 13 are predominantly dipolar in character

Evaluation of Veterinary-Specific Interpretive Criteria for Susceptibility Testing of Streptococcus equi Subspecies with Trimethoprim-Sulfamethoxazole and Trimethoprim-Sulfadiazine

DEFF Research Database (Denmark)

Sadaka, Carmen; Kanellos, Theo; Guardabassi, Luca

2017-01-01

Antimicrobial susceptibility test results for trimethoprim-sulfadiazine with Streptococcus equi subspecies are interpreted based on human data for trimethoprim-sulfamethoxazole. The veterinary-specific data generated in this study support a single breakpoint for testing trimethoprim-sulfamethoxaz......Antimicrobial susceptibility test results for trimethoprim-sulfadiazine with Streptococcus equi subspecies are interpreted based on human data for trimethoprim-sulfamethoxazole. The veterinary-specific data generated in this study support a single breakpoint for testing trimethoprim...

A cost-effective smartphone-based antimicrobial susceptibility test reader for drug resistance testing (Conference Presentation)

Science.gov (United States)

Feng, Steve W.; Tseng, Derek; Di Carlo, Dino; Garner, Omai B.; Ozcan, Aydogan

2017-03-01

Antimicrobial susceptibility testing (AST) is commonly used for determining microbial drug resistance, but routine testing, which can significantly reduce the spread of multi-drug resistant organisms, is not regularly performed in resource-limited and field-settings due to technological challenges and lack of trained diagnosticians. We developed a portable cost-effective smartphone-based colorimetric 96-well microtiter plate (MTP) reader capable of automated AST without the need for a trained diagnostician. This system is composed of a smartphone used in conjunction with a 3D-printed opto-mechanical attachment, which holds a set of inexpensive light-emitting-diodes and fiber-optic cables coupled to the 96-well MTP for enabling the capture of the transmitted light through each well by the smartphone camera. Images of the MTP plate are captured at multiple exposures and uploaded to a local or remote server (e.g., a laptop) for automated processing/analysis of the results using a custom-designed smartphone application. Each set of images are combined to generate a high dynamic-range image and analyzed for well turbidity (indicative of bacterial growth), followed by interpretative analysis per plate to determine minimum inhibitory concentration (MIC) and drug susceptibility for the specific bacterium. Results are returned to the originating device within 1 minute and shown to the user in tabular form. We demonstrated the capability of this platform using MTPs prepared with 17 antibiotic drugs targeting Gram-negative bacteria and tested 82 patient isolate MTPs of Klebsiella pneumoniae, achieving well turbidity accuracy of 98.19%, MIC accuracy of 95.15%, and drug susceptibility interpretation accuracy of 99.06%, meeting the FDA defined criteria for AST.

Rapid Antimicrobial Susceptibility Testing Using Forward Laser Light Scatter Technology.

Science.gov (United States)

Hayden, Randall T; Clinton, Lani K; Hewitt, Carolyn; Koyamatsu, Terri; Sun, Yilun; Jamison, Ginger; Perkins, Rosalie; Tang, Li; Pounds, Stanley; Bankowski, Matthew J

2016-11-01

The delayed reporting of antimicrobial susceptibility testing remains a limiting factor in clinical decision-making in the treatment of bacterial infection. This study evaluates the use of forward laser light scatter (FLLS) to measure bacterial growth for the early determination of antimicrobial susceptibility. Three isolates each (two clinical isolates and one reference strain) of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were tested in triplicate using two commercial antimicrobial testing systems, the Vitek2 and the MicroScan MIC panel, to challenge the BacterioScan FLLS. The BacterioScan FLLS showed a high degree of categorical concordance with the commercial methods. Pairwise comparison with each commercial system serving as a reference standard showed 88.9% agreement with MicroScan (two minor errors) and 72.2% agreement with Vitek (five minor errors). FLLS using the BacterioScan system shows promise as a novel method for the rapid and accurate determination of antimicrobial susceptibility. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Children's differential susceptibility to parenting: An experimental test of "for better and for worse".

Science.gov (United States)

Slagt, Meike; Dubas, Judith Semon; van Aken, Marcel A G; Ellis, Bruce J; Deković, Maja

2017-02-01

Differential susceptibility theory proposes that a subset of individuals exist who display enhanced susceptibility to both negative (risk-promoting) and positive (development-enhancing) environments. This experiment represents the first attempt to directly test this assumption by exposing children in the experimental group to both negative and positive feedback using puppet role-plays. It thereby serves as an empirical test as well as a methodological primer for testing differential susceptibility. Dutch children (N=190, 45.3% girls) between the ages of 4 and 6years participated. We examined whether negative and positive feedback would differentially affect changes in positive and negative affect, in prosocial and antisocial intentions and behavior, depending on children's negative emotionality. Results show that on hearing negative feedback, children in the experimental group increased in negative affect and decreased in positive affect more strongly than children in the control group. On hearing positive feedback, children in the experimental group tended to increase in positive affect and decrease in prosocial behavior. However, changes in response to negative or positive feedback did not depend on children's negative emotionality. Moreover, using reliable change scores, we found support for a subset of "vulnerable" children but not for a subset of "susceptible" children. The findings offer suggestions to guide future differential susceptibility experiments. Copyright © 2016 Elsevier Inc. All rights reserved.

Genetic susceptibility testing for chronic disease and intention for behavior change in healthy young adults.

Science.gov (United States)

Vassy, Jason L; Donelan, Karen; Hivert, Marie-France; Green, Robert C; Grant, Richard W

2013-04-01

Genetic testing for chronic disease susceptibility may motivate young adults for preventive behavior change. This nationally representative survey gave 521 young adults hypothetical scenarios of receiving genetic susceptibility results for heart disease, type 2 diabetes, and stroke and asked their (1) interest in such testing, (2) anticipated likelihood of improving diet and physical activity with high- and low-risk test results, and (3) readiness to make behavior change. Responses were analyzed by presence of established disease-risk factors. Respondents with high phenotypic diabetes risk reported increased likelihood of improving their diet and physical activity in response to high-risk results compared with those with low diabetes risk (odds ratio (OR), 1.82 (1.03, 3.21) for diet and OR, 2.64 (1.24, 5.64) for physical activity). In contrast, poor baseline diet (OR, 0.51 (0.27, 0.99)) and poor physical activity (OR, 0.53 (0.29, 0.99)) were associated with decreased likelihood of improving diet. Knowledge of genetic susceptibility may motivate young adults with higher personal diabetes risk for improvement in diet and exercise, but poor baseline behaviors are associated with decreased intention to make these changes. To be effective, genetic risk testing in young adults may need to be coupled with other strategies to enable behavior change.

Multisite reproducibility of the broth microdilution method for susceptibility testing of Nocardia species.

Science.gov (United States)

Conville, Patricia S; Brown-Elliott, Barbara A; Wallace, Richard J; Witebsky, Frank G; Koziol, Deloris; Hall, Geraldine S; Killian, Scott B; Knapp, Cindy C; Warshauer, David; Van, Tam; Wengenack, Nancy L; Deml, Sharon; Woods, Gail L

2012-04-01

Antimicrobial susceptibility testing (AST) of clinical isolates of Nocardia is recommended to detect resistance to commonly used antimicrobial agents; such testing is complicated by difficulties in inoculum preparation and test interpretation. In this study, six laboratories performed repetitive broth microdilution testing on single strains of Nocardia brasiliensis, Nocardia cyriacigeorgica, Nocardia farcinica, Nocardia nova, and Nocardia wallacei. For each isolate, a total of 30 microdilution panels from three different lots were tested at most sites. The goal of the study was to determine the inter- and intralaboratory reproducibility of susceptibility testing of this group of isolates. Acceptable agreement (>90% agreement at ±1 dilution of the MIC mode) was found for amikacin, ciprofloxacin, clarithromycin, and moxifloxacin. After eliminating MIC values from single laboratories whose results showed the greatest deviation from those of the remaining laboratories, acceptable agreement was also found for amoxicillin-clavulanic acid, linezolid, minocycline, and tobramycin. Results showed unsatisfactory reproducibility of broth microdilution testing of ceftriaxone with N. cyriacigeorgica and N. wallacei, tigecycline with N. brasiliensis and N. cyriacigeorgica, and sulfonamides with N. farcinica and N. wallacei. N. nova ATCC BAA-2227 is proposed as a quality control organism for AST of Nocardia sp., and the use of a disk diffusion test for sulfisoxazole is proposed as a check of the adequacy of the inoculum and to confirm sulfonamide MIC results.

Vancomycin-resistant enterococci: validation of susceptibility testing and in vitro activity of novel antibiotics

DEFF Research Database (Denmark)

Rathe, Mathias; Lise, Kristensen,; Ellermann-Eriksen, Svend

Vancomycin-resistant enterococci: validation of susceptibility testing and in vitro activity of novel antibiotics......Vancomycin-resistant enterococci: validation of susceptibility testing and in vitro activity of novel antibiotics...

Antibiotic susceptibility profiles for mastitis treatment.

Science.gov (United States)

Hinckley, L S; Benson, R H; Post, J E; DeCloux, J C

1985-10-01

Susceptibility tests were performed on milk samples representing prevalent mastitis infections in certain herds. Susceptibility patterns of the same bacterial species from several mastitis infections in the same herd were consistent. The herd antibiotic susceptibility profiles were used as a basis for selecting antibiotics for treatment of all such mastitis cases in that herd. A high degree of correlation was seen between the susceptibility test results and treatment results. Susceptibility patterns of the same bacterial species from mastitis infections in different herds varied greatly, which indicated that any one antibiotic would not work equally well against the same bacterial infection in every herd. Therefore, treatment should be selected on the basis of susceptibility test results. When both Streptococcus and Staphylococcus mastitis occurred in the same herd, the susceptibility patterns for the 2 bacterial species varied widely. Therefore, for herds that experienced both streptococcal and staphylococcal mastitis, antibiotics to which both bacterial species were susceptible were used for treatment.

Antimicrobial susceptibility of quinupristin/dalfopristin tested against gram-positive cocci from Latin America: results from the Global SMART (GSMART surveillance study

Directory of Open Access Journals (Sweden)

Sader Helio S.

2001-01-01

Full Text Available Gram-positive cocci are important causes of both nosocomial and community-acquired infections, and antimicrobial resistance among these pathogens has become an important problem worldwide. Since resistance among these organisms can vary substantially by geographic location, we conducted a multicenter surveillance study with isolates from five Latin American countries (15 medical centers. Quinupristin/dalfopristin (formerly RP-59500 is a novel streptogramin combination with focused activity against Gram-positive cocci, many exhibiting emerging resistance. The in vitro activity of quinupristin/dalfopristin and 12 other antimicrobial agents were evaluated against 1,948 strains including Staphylococcus aureus (747 strains, coagulase-negative staphylococci (CoNS; 446 strains, enterococci (429 strains, and various Streptococcus spp. (326 strains. Oxacillin resistance was observed in 41% of S. aureus (MIC, or = 13 mm and 40% of CoNS (MIC, or = 18 mm. Vancomycin, teicoplanin, and quinupristin/dalfopristin (MIC90, 0.25 - 1 mug/ml remained effective against all strains, but cross-resistance was high among other tested drugs. The quinupristin/dalfopristin MIC50 for Streptococcus pneumoniae and other streptococci was only 0.5 mug/ml (13% to 28% were penicillin-resistant; 12% to 22% were macrolide-resistant. Enterococci demonstrated variable inhibition by quinupristin/dalfopristin depending upon identification and the susceptibility testing method used. The demonstrated quinupristin/dalfopristin activity against Enterococcus faecium was confirmed, but potential species identification errors with various commercial systems continue to confuse susceptibility statistics, even though some strains of E. faecium confirmed by PCR-based or other molecular identification techniques did have quinupristin/dalfopristin MICs of > or = 4 mug/mL. Most important, glycopeptide-resistant enterococci are rapidly emerging in Latin America, and quinupristin/dalfopristin appears

suitability of vitek 2 system in identification and susceptibility testing

African Journals Online (AJOL)

2014-04-01

Apr 1, 2014 ... susceptibility testing (AST) of bacteria from blood are ... This process ... This was a method validation study carried out at .... testing: Of the 19 cultures with AST by direct Vitek, three had discrepancies for some antibiotics.

21 CFR 866.1620 - Antimicrobial susceptibility test disc.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Antimicrobial susceptibility test disc. 866.1620 Section 866.1620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Diagnostic Devices § 866.1620 Antimicrobial...

Bacterial Cytological Profiling (BCP as a Rapid and Accurate Antimicrobial Susceptibility Testing Method for Staphylococcus aureus

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D.T. Quach

2016-02-01

Full Text Available Successful treatment of bacterial infections requires the timely administration of appropriate antimicrobial therapy. The failure to initiate the correct therapy in a timely fashion results in poor clinical outcomes, longer hospital stays, and higher medical costs. Current approaches to antibiotic susceptibility testing of cultured pathogens have key limitations ranging from long run times to dependence on prior knowledge of genetic mechanisms of resistance. We have developed a rapid antimicrobial susceptibility assay for Staphylococcus aureus based on bacterial cytological profiling (BCP, which uses quantitative fluorescence microscopy to measure antibiotic induced changes in cellular architecture. BCP discriminated between methicillin-susceptible (MSSA and -resistant (MRSA clinical isolates of S. aureus (n = 71 within 1–2 h with 100% accuracy. Similarly, BCP correctly distinguished daptomycin susceptible (DS from daptomycin non-susceptible (DNS S. aureus strains (n = 20 within 30 min. Among MRSA isolates, BCP further identified two classes of strains that differ in their susceptibility to specific combinations of beta-lactam antibiotics. BCP provides a rapid and flexible alternative to gene-based susceptibility testing methods for S. aureus, and should be readily adaptable to different antibiotics and bacterial species as new mechanisms of resistance or multidrug-resistant pathogens evolve and appear in mainstream clinical practice.

Rapid susceptibility testing of Mycobacterium tuberculosis by bioluminescence assay of mycobacterial ATP

International Nuclear Information System (INIS)

Nilsson, L.E.; Hoffner, S.E.; Ansehn, S.

1988-01-01

Mycobacterial growth was monitored by bioluminescence assay of mycobacterial ATP. Cultures of Mycobacterium tuberculosis H37Rv and of 25 clinical isolates of the same species were exposed to serial dilutions of ethambutol, isoniazid, rifampin, and streptomycin. A suppression of ATP, indicating growth inhibition, occurred for susceptible but not resistant strains within 5 to 7 days of incubation. Breakpoint concentrations between susceptibility and resistance were determined by comparing these results with those obtained by reference techniques. Full agreement was found in 99% of the assays with the resistance ratio method on Lowenstein-Jensen medium, and 98% of the assays were in full agreement with the radiometric system (BACTEC). A main advantage of the bioluminescence method is its rapidity, with results available as fast as with the radiometric system but at a lower cost and without the need for radioactive culture medium. The method provides kinetic data concerning drug effects within available in vivo drug concentrations and has great potential for both rapid routine susceptibility testing and research applications in studies of drug effects on mycobacteria

Simple Sample Preparation Method for Direct Microbial Identification and Susceptibility Testing From Positive Blood Cultures.

Science.gov (United States)

Pan, Hong-Wei; Li, Wei; Li, Rong-Guo; Li, Yong; Zhang, Yi; Sun, En-Hua

2018-01-01

Rapid identification and determination of the antibiotic susceptibility profiles of the infectious agents in patients with bloodstream infections are critical steps in choosing an effective targeted antibiotic for treatment. However, there has been minimal effort focused on developing combined methods for the simultaneous direct identification and antibiotic susceptibility determination of bacteria in positive blood cultures. In this study, we constructed a lysis-centrifugation-wash procedure to prepare a bacterial pellet from positive blood cultures, which can be used directly for identification by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and antibiotic susceptibility testing by the Vitek 2 system. The method was evaluated using a total of 129 clinical bacteria-positive blood cultures. The whole sample preparation process could be completed in identification was 96.49% for gram-negative bacteria and 97.22% for gram-positive bacteria. Vitek 2 antimicrobial susceptibility testing of gram-negative bacteria showed an agreement rate of antimicrobial categories of 96.89% with a minor error, major error, and very major error rate of 2.63, 0.24, and 0.24%, respectively. Category agreement of antimicrobials against gram-positive bacteria was 92.81%, with a minor error, major error, and very major error rate of 4.51, 1.22, and 1.46%, respectively. These results indicated that our direct antibiotic susceptibility analysis method worked well compared to the conventional culture-dependent laboratory method. Overall, this fast, easy, and accurate method can facilitate the direct identification and antibiotic susceptibility testing of bacteria in positive blood cultures.

Interpretive criteria of antimicrobial disk susceptibility tests with flomoxef.

Science.gov (United States)

Grimm, H

1991-01-01

320 recently isolated pathogens, 20 strains from each of 16 species, were investigated using Mueller-Hinton agar and DIN as well as NCCLS standards. The geometric mean of the agar dilution MICs of flomoxef were 0.44 mg/l for Staphylococcus aureus, 0.05 mg/l (Klebsiella oxytoca) to 12.6 mg/l (Enterobacter spp.) for enterobacteriaceae, 33.1 mg/l for Acinetobacter anitratus, 64 mg/l for Enterococcus faecalis, and more than 256 mg/l for Pseudomonas aeruginosa. For disk susceptibility testing of flomoxef a 30 micrograms disk loading and the following interpretation of inhibition zones using the DIN method were recommended: resistant-up to 22 mm (corresponding to MICs of 8 mg/l or more), moderately susceptible-23 to 29 mm (corresponding to MICs from 1 to 4 mg/l), and susceptible-30 mm or more (corresponding to MICs of 0.5 mg/l or less). The respective values for the NCCLS method using the American high MIC breakpoints are: resistant--up to 14 mm (corresponding to MICs of 32 mg/l or more), moderately susceptible--15 to 17 mm (corresponding to MICs of 16 mg/l), and susceptible--18 mm or more (corresponding to MICs of 8 mg/l or less).

Antiobiotics susceptibility of Salmonella isolates from Wdal Test ...

African Journals Online (AJOL)

Antiobiotics susceptibility of Salmonella isolates from Wdal Test Positive Patients at the Federal Medical Center, Gusau. SB Manga, IG Ameh, S Bashir, AG Muazu, B Danjuma, ML Ibrahim, K Abdullahi, J Mawak. Abstract. No Abstract Supplied. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD ...

Awareness of Cancer Susceptibility Genetic Testing

Science.gov (United States)

Mai, Phuong L.; Vadaparampil, Susan Thomas; Breen, Nancy; McNeel, Timothy S.; Wideroff, Louise; Graubard, Barry I.

2014-01-01

Background Genetic testing for several cancer susceptibility syndromes is clinically available; however, existing data suggest limited population awareness of such tests. Purpose To examine awareness regarding cancer genetic testing in the U.S. population aged ≥25 years in the 2000, 2005, and 2010 National Health Interview Surveys. Methods The weighted percentages of respondents aware of cancer genetic tests, and percent changes from 2000–2005 and 2005–2010, overall and by demographic, family history, and healthcare factors were calculated. Interactions were used to evaluate the patterns of change in awareness between 2005 and 2010 among subgroups within each factor. To evaluate associations with awareness in 2005 and 2010, percentages were adjusted for covariates using multiple logistic regression. The analysis was performed in 2012. Results Awareness decreased from 44.4% to 41.5% (pAwareness increased between 2005 and 2010 in most subgroups, particularly among individuals in the South (p-interaction=0.03) or with a usual place of care (p-interaction=0.01). In 2005 and 2010, awareness was positively associated with personal or family cancer history and high perceived cancer risk, and inversely associated with racial/ethnic minorities, age 25–39 or ≥60 years, male gender, lower education and income levels, public or no health insurance, and no provider contact in 12 months. Conclusions Despite improvement from 2005 to 2010, ≤50% of the U.S. adult population was aware of cancer genetic testing in 2010. Notably, disparities persist for racial/ethnic minorities and individuals with limited health care access or income. PMID:24745633

21 CFR 866.1700 - Culture medium for antimicrobial susceptibility tests.

Science.gov (United States)

2010-04-01

... tests. 866.1700 Section 866.1700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Diagnostic Devices § 866.1700 Culture medium for antimicrobial susceptibility tests. (a) Identification. A culture medium for...

Rapid bacterial antibiotic susceptibility test based on simple surface-enhanced Raman spectroscopic biomarkers

Science.gov (United States)

Liu, Chia-Ying; Han, Yin-Yi; Shih, Po-Han; Lian, Wei-Nan; Wang, Huai-Hsien; Lin, Chi-Hung; Hsueh, Po-Ren; Wang, Juen-Kai; Wang, Yuh-Lin

2016-03-01

Rapid bacterial antibiotic susceptibility test (AST) and minimum inhibitory concentration (MIC) measurement are important to help reduce the widespread misuse of antibiotics and alleviate the growing drug-resistance problem. We discovered that, when a susceptible strain of Staphylococcus aureus or Escherichia coli is exposed to an antibiotic, the intensity of specific biomarkers in its surface-enhanced Raman scattering (SERS) spectra drops evidently in two hours. The discovery has been exploited for rapid AST and MIC determination of methicillin-susceptible S. aureus and wild-type E. coli as well as clinical isolates. The results obtained by this SERS-AST method were consistent with that by the standard incubation-based method, indicating its high potential to supplement or replace existing time-consuming methods and help mitigate the challenge of drug resistance in clinical microbiology.

Microbial sensor for drug susceptibility testing of Mycobacterium tuberculosis.

Science.gov (United States)

Zhang, Z-T; Wang, D-B; Li, C-Y; Deng, J-Y; Zhang, J-B; Bi, L-J; Zhang, X-E

2018-01-01

Drug susceptibility testing (DST) of clinical isolates of Mycobacterium tuberculosis is critical in treating tuberculosis. We demonstrate the possibility of using a microbial sensor to perform DST of M. tuberculosis and shorten the time required for DST. The sensor is made of an oxygen electrode with M. tuberculosis cells attached to its surface. This sensor monitors the residual oxygen consumption of M. tuberculosis cells after treatment with anti-TB drugs with glycerine as a carbon source. In principle, after drug pretreatment for 4-5 days, the response differences between the sensors made of drug-sensitive isolates are distinguishable from the sensors made of drug-resistant isolates. The susceptibility of the M. tuberculosis H37Ra strain, its mutants and 35 clinical isolates to six common anti-TB drugs: rifampicin, isoniazid, streptomycin, ethambutol, levofloxacin and para-aminosalicylic acid were tested using the proposed method. The results agreed well with the gold standard method (LJ) and were determined in significantly less time. The whole procedure takes approximately 11 days and therefore has the potential to inform clinical decisions. To our knowledge, this is the first study that demonstrates the possible application of a dissolved oxygen electrode-based microbial sensor in M. tuberculosis drug resistance testing. This study used the microbial sensor to perform DST of M. tuberculosis and shorten the time required for DST. The overall detection result of the microbial sensor agreed well with that of the conventional LJ proportion method and takes less time than the existing phenotypic methods. In future studies, we will build an O 2 electrode array microbial sensor reactor to enable a high-throughput drug resistance analysis. © 2017 The Authors. Journal of Applied Microbiology published by John Wiley & Sons Ltd on behalf of The Society for Applied Microbiology.

Candidaemia and antifungal susceptibility testing in a teaching hospital.

Science.gov (United States)

Tzar, M N; Shamim, A S

2009-03-01

We reviewed cases of candidaemia at Universiti Kebangsaan Malaysia Medical Centre from 1st January 2005 to 30th June 2006. All blood cultures positive for Candida species or its teleomorphs within the study period were identified and antifungal susceptibility testing was performed. Out of 50 blood isolates, 20 (40%) were identified as Candida albicans, 16 (32%) C. tropicalis, five (10%) C. parapsilosis, three (6%) C. famata, two (4%) C. glabrata, two (4%) Pichia ohmeri, one (2%) C. krusei and one (2%) P. etchell/carsonii. Susceptibility to amphotericin B was 100%, fluconazole 90%, itraconazole 40%, ketoconazole 88%, 5-flucytosine 98% and voriconazole 98%.

Simple Sample Preparation Method for Direct Microbial Identification and Susceptibility Testing From Positive Blood Cultures

Directory of Open Access Journals (Sweden)

Hong-wei Pan

2018-03-01

Full Text Available Rapid identification and determination of the antibiotic susceptibility profiles of the infectious agents in patients with bloodstream infections are critical steps in choosing an effective targeted antibiotic for treatment. However, there has been minimal effort focused on developing combined methods for the simultaneous direct identification and antibiotic susceptibility determination of bacteria in positive blood cultures. In this study, we constructed a lysis-centrifugation-wash procedure to prepare a bacterial pellet from positive blood cultures, which can be used directly for identification by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS and antibiotic susceptibility testing by the Vitek 2 system. The method was evaluated using a total of 129 clinical bacteria-positive blood cultures. The whole sample preparation process could be completed in <15 min. The correct rate of direct MALDI-TOF MS identification was 96.49% for gram-negative bacteria and 97.22% for gram-positive bacteria. Vitek 2 antimicrobial susceptibility testing of gram-negative bacteria showed an agreement rate of antimicrobial categories of 96.89% with a minor error, major error, and very major error rate of 2.63, 0.24, and 0.24%, respectively. Category agreement of antimicrobials against gram-positive bacteria was 92.81%, with a minor error, major error, and very major error rate of 4.51, 1.22, and 1.46%, respectively. These results indicated that our direct antibiotic susceptibility analysis method worked well compared to the conventional culture-dependent laboratory method. Overall, this fast, easy, and accurate method can facilitate the direct identification and antibiotic susceptibility testing of bacteria in positive blood cultures.

Mycobacterium abscessus subsp. abscessus Lung Disease: Drug Susceptibility Testing in Sputum Culture Negative Conversion

Directory of Open Access Journals (Sweden)

Takehiko Kobayashi

2018-01-01

Full Text Available Background: Among Mycobacterium abscessus complex infections, patients with M. abscessus subsp. abscessus (MAA lung disease are difficult to treat and no standard therapy has been established. Few reports have investigated the drug susceptibility of these strains. We retrospectively investigated how in vitro drug susceptibility testing (DST of MAA affects the induction of sputum conversion using pharmacotherapy. Methods: Patients with MAA lung disease diagnosed and treated between 2010 and 2014 at our hospital were enrolled and divided into Group A (sputum conversion without relapse within 1 year and Group B (persistent positive cultured or negative conversion with relapse. MAA was identified in M. abscessus using sequence with genotyping, and DST of MAA was performed. Results: We assessed 23 patients (9 males and 14 females. There were 8 patients in Group A and 15 in Group B. Higher prevalence of susceptible isolates for clarithromycin (CAM susceptibility on day 14 was noted in Group A than in Group B (P = 0.03 and no significant difference observed in the two groups for other drugs. Conclusions: In vitro DST of MAA, especially CAM susceptibility on day 14, affected the results of negative conversion. No other drugs were found to affect sputum culture negative conversion.

ANTIFUNGAL SUSCEPTIBILITY TESTING: CURRENT ROLE FROM THE CLINICAL LABORATORY PERSPECTIVE

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Brunella Posteraro

2014-04-01

Full Text Available Despite availability of many antifungal agents, antifungal clinical resistance occurs, perhaps as a result of an infecting organism found to be resistant in vitro to one or more antifungals tested. Thus, antifungal susceptibility testing (AFST results, if timely generated by the clinical microbiology and communicated to clinicians, can aid them in the therapeutic decision making, especially for difficult-to-treat invasive candidiasis and aspergillosis. Although recently refined AFST methods are commercially available to allow a close antifungal resistance surveillance in many clinical setting, novel assays, relying on short-time antifungal drug exposure of fungal isolates, are upcoming tools for AFST. Based on emerging technologies such as flow cytometry, MALDI-TOF mass spectrometry, and isothermal microcalorimetry, these assays could provide a reliable means for quicker and sensitive assessment of AFST.

Direct identification and susceptibility testing of positive blood cultures using high speed cold centrifugation and Vitek II system.

Science.gov (United States)

Bazzi, Ali M; Rabaan, Ali A; Fawarah, Mahmoud M; Al-Tawfiq, Jaffar A

Compared to routine isolated colony-based methods, direct testing of bacterial pellets from positive blood cultures reduces turnaround time for reporting of antibiotic susceptibility. The aim of this study was to compare the accuracy, and precision, of a rapid method for direct identification and susceptibility testing of blood cultures with the routine method used in our laboratory, using Vitek 2. A total of 60 isolates were evaluated using the candidate and the routine method. The candidate method had 100% accuracy for the identification of Gram negative bacteria, Staphylococcus and Enterococcus, 50% for Streptococcus and 33.3% for Corynebacterium species. Susceptibility testing of Gram negative isolates yielded 98-100% essential agreement. For Staphylococcus and Enterococcus isolates, essential agreement was 100% for 17 antibiotics except for moxifloxacin. Direct testing of blood culture samples with Vitek 2 produced reliable identification and susceptibility results 18-24h sooner for aerobic/anaerobic facultative Gram-negative bacteria and Gram-positive Staphylococcus and Enterococcus strains. Copyright © 2016 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

Susceptibility Testing by Polymerase Chain Reaction DNA Quantitation: A Method to Measure Drug Resistance of Human Immunodeficiency Virus Type 1 Isolates

Science.gov (United States)

Eron, Joseph J.; Gorczyca, Paul; Kaplan, Joan C.; D'Aquila, Richard T.

1992-04-01

Polymerase chain reaction (PCR) DNA quantitation (PDQ) susceptibility testing rapidly and directly measures nucleoside sensitivity of human immunodeficiency virus type 1 (HIV-1) isolates. PCR is used to quantitate the amount of HIV-1 DNA synthesized after in vitro infection of peripheral blood mononuclear cells. The relative amounts of HIV-1 DNA in cell lysates from cultures maintained at different drug concentrations reflect drug inhibition of virus replication. The results of PDQ susceptibility testing of 2- or 3-day cultures are supported by assays measuring HIV-1 p24 antigen production in supernatants of 7- or 10-day cultures. DNA sequence analyses to identify mutations in the reverse transcriptase gene that cause resistance to 3'-azido-3'-deoxythymidine also support the PDQ results. With the PDQ method, both infectivity titration and susceptibility testing can be performed on supernatants from primary cultures of peripheral blood mononuclear cells. PDQ susceptibility testing should facilitate epidemiologic studies of the clinical significance of drug-resistant HIV-1 isolates.

Evaluation of an Automated System for Reading and Interpreting Disk Diffusion Antimicrobial Susceptibility Testing of Fastidious Bacteria.

Science.gov (United States)

Idelevich, Evgeny A; Becker, Karsten; Schmitz, Janne; Knaack, Dennis; Peters, Georg; Köck, Robin

2016-01-01

Results of disk diffusion antimicrobial susceptibility testing depend on individual visual reading of inhibition zone diameters. Therefore, automated reading using camera systems might represent a useful tool for standardization. In this study, the ADAGIO automated system (Bio-Rad) was evaluated for reading disk diffusion tests of fastidious bacteria. 144 clinical isolates (68 β-haemolytic streptococci, 28 Streptococcus pneumoniae, 18 viridans group streptococci, 13 Haemophilus influenzae, 7 Moraxella catarrhalis, and 10 Campylobacter jejuni) were tested on Mueller-Hinton agar supplemented with 5% defibrinated horse blood and 20 mg/L β-NAD (MH-F, Oxoid) according to EUCAST. Plates were read manually with a ruler and automatically using the ADAGIO system. Inhibition zone diameters, indicated by the automated system, were visually controlled and adjusted, if necessary. Among 1548 isolate-antibiotic combinations, comparison of automated vs. manual reading yielded categorical agreement (CA) without visual adjustment of the automatically determined zone diameters in 81.4%. In 20% (309 of 1548) of tests it was deemed necessary to adjust the automatically determined zone diameter after visual control. After adjustment, CA was 94.8%; very major errors (false susceptible interpretation), major errors (false resistant interpretation) and minor errors (false categorization involving intermediate result), calculated according to the ISO 20776-2 guideline, accounted to 13.7% (13 of 95 resistant results), 3.3% (47 of 1424 susceptible results) and 1.4% (21 of 1548 total results), respectively, compared to manual reading. The ADAGIO system allowed for automated reading of disk diffusion testing in fastidious bacteria and, after visual validation of the automated results, yielded good categorical agreement with manual reading.

In-vitro antimycobacterial drug susceptibility testing of non-tubercular mycobacteria by tetrazolium microplate assay.

Science.gov (United States)

Sankar, Manimuthu Mani; Gopinath, Krishnamoorthy; Singla, Roopak; Singh, Sarman

2008-07-11

Non-tubercular mycobacteria (NTM) has not been given due attention till the recent epidemic of HIV. This has led to increasing interest of health care workers in their biology, epidemiology and drug resistance. However, timely detection and drug susceptibility profiling of NTM isolates are always difficult in resource poor settings like India. Furthermore, no standardized methodology or guidelines are available to reproduce the results with clinical concordance. To find an alternative and rapid method for performing the drug susceptibility assay in a resource limited settings like India, we intended to evaluate the utility of Tetrazolium microplate assay (TEMA) in comparison with proportion method for reporting the drug resistance in clinical isolates of NTM. A total of fifty-five NTM isolates were tested for susceptibility against Streptomycin, Rifampicin, Ethambutol, Ciprofloxacin, Ofloxacin, Azithromycin, and Clarithromycin by TEMA and the results were compared with agar proportion method (APM). Of the 55 isolates, 23 (41.8%) were sensitive to all the drugs and the remaining 32 (58.2%) were resistant to at least one drug. TEMA had very good concordance with APM except with minor discrepancies. Susceptibility results were obtained in the median of 5 to 9 days by TEMA. The NTM isolates were highly sensitive against Ofloxacin (98.18% sensitive) and Ciprofloxacin (90.09% sensitive). M. mucogenicum was sensitive only to Clarithromycin and resistant to all the other drugs tested. The concordance between TEMA and APM ranged between 96.4 - 100%. Tetrazolium Microplate Assay is a rapid and highly reproducible method. However, it must be performed only in tertiary level Mycobacteriology laboratories with proper bio-safety conditions.

Proposal for agar disk diffusion interpretive criteria for susceptibility testing of bovine mastitis pathogens using cefoperazone 30μg disks.

Science.gov (United States)

Feßler, Andrea T; Kaspar, Heike; Lindeman, Cynthia J; Peters, Thomas; Watts, Jeffrey L; Schwarz, Stefan

2017-02-01

Cefoperazone is a third generation cephalosporin which is commonly used for bovine mastitis therapy. Bacterial pathogens involved in bovine mastitis are frequently tested for their susceptibility to cefoperazone. So far, the cefoperazone susceptibility testing using 30μg disks has been hampered by the lack of quality control (QC) ranges as well as the lack of interpretive criteria. In 2014, QC ranges for 30 μg cefoperazone disks have been established for Staphylococcus aureus ATCC ® 25923 and Escherichia coli ATCC ® 25922. As a next step, interpretive criteria for the susceptibility testing of bovine mastitis pathogens should be developed. For this, 637 bovine mastitis pathogens (including 112 S. aureus, 121 coagulase-negative staphylococci (CoNS), 103 E. coli, 101 Streptococcus agalactiae, 100 Streptococcus dysgalactiae and 100 Streptococcus uberis) were investigated by agar disk diffusion according to the document Vet01-A4 of the Clinical and Laboratory Standards Institute (CLSI) using 30μg cefoperazone disks and the results were compared to the corresponding MIC values as determined by broth microdilution also according to the aforementioned CLSI document. Based on the results obtained and taking into account the achievable milk concentration of cefoperazone after regular dosing, the following interpretive criteria were proposed as a guidance for mastitis diagnostic laboratories: for staphylococci and E. coli ≥23mm (susceptible), 18-22mm (intermediate) and ≤17mm (resistant) and for streptococci ≥18mm (susceptible), and ≤17mm (non-susceptible). These proposed interpretive criteria shall contribute to a harmonization of cefoperazone susceptibility testing of bovine mastitis pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

Detection and antifungal susceptibility testing of oral Candida dubliniensis from human immunodeficiency virus-infected patients

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Chunchanur Sneha

2009-10-01

Full Text Available Context: Candida dubliniensis, an opportunistic yeast that has been implicated in oropharyngeal candidiasis (OPC in patients infected with Human Immunodeficiency Virus (HIV may be under-reported due to its similarity with Candida albicans. Resistance to Fluconazole is often seen in C. dubliniensis isolates from clinical specimens. Aims: To know the prevalence of C. dubliniensis in OPC in patients infected with HIV and their antifungal susceptibility pattern. Settings and Design: One hundred and thirty-two HIV seropositive individuals and 50 healthy controls were included in the study. Materials and Methods: Two oral swabs were collected from the site of the lesion from 132 HIV-infected patients. Oral rinse was obtained from 50 healthy controls. Samples were inoculated on Sabouraud′s dextrose agar (SDA medium and on HiCrome Candida Differential Agar (CHROM agar medium. Isolates were speciated by standard tests. Dark green-colored, germ tube positive isolates, which failed to grow at 420C and negative for xylose assimilation were identified as C. dubliniensis. Antifungal susceptibility test was performed by Macro broth dilution technique (National Committee for Clinical Laboratory Standards guidelines. Results and Conclusions: From 132 patients, 22 (16.3% C. dubliniensis were isolated; samples from healthy controls did not reveal their presence. Antifungal susceptibility test showed higher resistance among C. dubliniensis isolates to azoles compared to C. albicans. Five (22.7% isolates of C. dubliniensis were resistant to Fluconazole followed by four (18.2% to Ketoconazole. This study emphasizes the importance of identification and antifungal susceptibility testing of C. dubliniensis in HIV-infected patients.

Impact of Rapid Susceptibility Testing and Antibiotic Selection Strategy on the Emergence and Spread of Antibiotic Resistance in Gonorrhea.

Science.gov (United States)

Tuite, Ashleigh R; Gift, Thomas L; Chesson, Harrell W; Hsu, Katherine; Salomon, Joshua A; Grad, Yonatan H

2017-11-27

Increasing antibiotic resistance limits treatment options for gonorrhea. We examined the impact of a hypothetical point-of-care (POC) test reporting antibiotic susceptibility profiles on slowing resistance spread. A mathematical model describing gonorrhea transmission incorporated resistance emergence probabilities and fitness costs associated with resistance based on characteristics of ciprofloxacin (A), azithromycin (B), and ceftriaxone (C). We evaluated time to 1% and 5% prevalence of resistant strains among all isolates with the following: (1) empiric treatment (B and C), and treatment guided by POC tests determining susceptibility to (2) A only and (3) all 3 antibiotics. Continued empiric treatment without POC testing was projected to result in >5% of isolates being resistant to both B and C within 15 years. Use of either POC test in 10% of identified cases delayed this by 5 years. The 3 antibiotic POC test delayed the time to reach 1% prevalence of triply-resistant strains by 6 years, whereas the A-only test resulted in no delay. Results were less sensitive to assumptions about fitness costs and test characteristics with increasing test uptake. Rapid diagnostics reporting antibiotic susceptibility may extend the usefulness of existing antibiotics for gonorrhea treatment, but ongoing monitoring of resistance patterns will be critical. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

Typhoid outbreak in Songkhla, Thailand 2009-2011: clinical outcomes, susceptibility patterns, and reliability of serology tests.

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Wannee Limpitikul

Full Text Available OBJECTIVE: To determine the clinical manifestations and outcomes, the reliability of Salmonella enterica serotype Typhi (S ser. Typhi IgM and IgG rapid tests, and the susceptibility patterns and the response to treatment during the 2009-2011 typhoid outbreak in Songkhla province in Thailand. METHOD: The medical records of children aged <15 years with S ser. Typhi bacteremia were analysed. The efficacy of the typhoid IgM and IgG rapid tests and susceptibility of the S ser. Typhi to the current main antibiotics used for typhoid (amoxicillin, ampicillin, cefotaxime, ceftriaxone, co-trimoxazole, and ciprofloxacin, were evaluated. RESULTS: S ser. Typhi bacteremia was found in 368 patients, and all isolated strains were susceptible to all 6 antimicrobials tested. Most of the patients were treated with ciprofloxacin for 7-14 days. The median time (IQR of fever before treatment and duration of fever after treatment were 5 (4, 7 days and 4 (3, 5 days, respectively. Complications of ascites, lower respiratory symptoms, anemia (Hct <30%, and ileal perforation were found in 7, 7, 22, and 1 patients, respectively. None of the patients had recurrent infection or died. The sensitivities of the typhoid IgM and IgG tests were 58.3% and 25.6% respectively, and specificities were 74.1% and 50.5%, respectively. CONCLUSION: Most of the patients were diagnosed at an early stage and treated with a good outcome. All S ser. Typhi strains were susceptible to standard first line antibiotic typhoid treatment. The typhoid IgM and IgG rapid tests had low sensitivity and moderate specificity.

Parallel susceptibility testing of bacteria through culture-quantitative PCR in 96-well plates

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Jun Luo

2018-05-01

Full Text Available Objective: The methods combining culture and quantitative PCR(qPCR offer new solutions for rapid antibiotic susceptibility testing(AST. However, the multiple steps of DNA extraction and cold storage of PCR reagents needed make them unsuitable for rapid high throughput AST. In this study, a parallel culture-qPCR method was developed to overcome above problems. Method: In this method, bacteria culture and DNA extraction automatically and simultaneously completed through using a common PCR instrument as a controllable heating device. A lyophilized 16S rDNA targeted qPCR reagent was also developed, which was stable and could be kept at 4 °C for long time and at 37 °C for about two months. Result: Testing of 36 P. aeruginosa isolates and 28 S. aureus isolates showed that the method had good agreements with the standard broth microdilution method, with an overall agreement of 97.22% (95% CI, 85.83–99.51 for P. aeruginosa and 96.43% (95% CI, 79.76–99.81 for S. aureus. This method could test 12 samples against a panel of up to 7 antibiotics simultaneously in two 96-well PCR plates within 4 h, which greatly improves the testing efficiency of the culture-qPCR method. Conclusion: With rapidness to obtain results and the capabilities for automation and multiple-sample testing, the parallel culture-qPCR method would have great potentials in clinical labs. Keywords: Antibiotic susceptibility testing, Thermo-cold lysis, Lyophilized qPCR reagent, Quantitative PCR, Bacteria

Quality assurance for antimicrobial susceptibility testing of Neisseria gonorrhoeae in Latin American and Caribbean countries, 2013-2015.

Science.gov (United States)

Sawatzky, Pam; Martin, Irene; Galarza, Patricia; Carvallo, Marıa Elena Trigoso; Araya Rodriguez, Pamela; Cruz, Olga Marina Sanabria; Hernandez, Alina Llop; Martinez, Mario Fabian; Borthagaray, Graciela; Payares, Daisy; Moreno, José E; Chiappe, Marina; Corredor, Aura Helena; Thakur, Sidharath Dev; Dillon, Jo-Anne R

2018-04-19

A Neisseria gonorrhoeae antimicrobial susceptibility quality control comparison programme was re-established in Latin America and the Caribbean to ensure antimicrobial susceptibility data produced from the region are comparable nationally and internationally. Three panels, consisting of N. gonorrhoeae isolates comprising reference strains and other characterised isolates were sent to 11 participating laboratories between 2013 and 2015. Antimicrobial susceptibilities for these isolates were determined using agar dilution, Etest or disc diffusion methods. Modal minimum inhibitory concentrations (MICs) for each panel isolate/antibiotic combination were calculated. The guidelines of the Clinical and Laboratory Standards Institute were used for interpretations of antimicrobial susceptibility. The agreement of MICs with the modal MICs was determined for each of the participating laboratories as well as for each of the antibiotics tested. Five of 11 laboratories that participated in at least one panel had an overall average agreement between participants' MIC results and modal MICs of >90%. For other laboratories, agreements ranged from 60.0% to 82.4%. The proportion of agreement between interpretations for all the antibiotics, except penicillin and tetracycline, was >90%. The percentages of agreement between MIC results and their modes for erythromycin, spectinomycin, cefixime and azithromycin were >90%. Tetracycline, ceftriaxone and ciprofloxacin agreement ranged from 84.5% to 89.1%, while penicillin had 78.8% agreement between MICs and modal MICs. The participating laboratories had acceptable results, similar to other international quality assurance programmes. It is important to ensure continuation of the International Gonococcal Antimicrobial Susceptibility Quality Control Comparison Programme to ensure that participants can identify and correct any problems in antimicrobial susceptibility testing for N. gonorrhoeae as they arise and continue to generate reproducible

New method for rapid Susceptibility Testing on blood culture with HB&L system: preliminary data

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Vincenzo Rondinelli

2010-12-01

Full Text Available Blood culture, although represents the gold standard in detecting the ethiological agent of sepsis, is rather rarely required in relation to the real diagnostic importance. The result of this test depends in fact on many factors (sample volume, time of collection, accuracy, antibiotic therapy, contamination, number of drawings, drawing site, interpretation difficulties, etc. that are often considered by many clinicians so limited as to doubt about their actual value. The disadvantages are therefore represented by the lack of standardization but also by the low sensitivity and above all by the technical times too long for the clinical needs. Blood culture begins with the drawing of samples from the “septic” patient followed incubation of the bottles in automatic thermostated systems. In case of positive result (36 hours, the culture is Gram stained and streaked on solid media in order to obtain isolated colonies for the identification and the susceptibility testing (48 hours from positive result. The long time required for pathogen identification and susceptibility testing involves empirical broad spectrum antibiotic therapy that can promote the increase of bacterial resistance but also patient management costs. A clinically useful report should be available on short notice in order to guide the clinician to choose the most appropriate antibiotic. The microbiologist has therefore the hard work of reviewing the organization and the management of the procedures.We have therefore started to consider the possibility of treating the blood as an biological liquid in order to quickly determine the susceptibility of bacteria to antibiotics.

SCC susceptibility evaluation of plastic deformed austenitic stainless steels

Energy Technology Data Exchange (ETDEWEB)

Kaneshima, Yoshiari; Totsuka, Nobuo; Arioka, Koji [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2002-09-01

Slow strain rate temperature (SSRT) tests were carried out to evaluate the SCC susceptibility of deformed SUS316 stainless steel in simulated primary water of pressurized water reactor (PWR). The influence of material hardness and temperature on SCC susceptibility was studied. From these tests following results were obtained. (1) Both of the total SCC and IGSCC susceptibilities increased as the hardness of deformed specimens increased. Especially over 250{approx}300HV area, this tendency remarkably increased. (2) The reduction ratio showed a plateau under 300HV area. However, over 300HV area, it decreased remarkably as the hardness increased, that is, the SCC susceptibility remarkably increased. (3) Based on the SSRT test results conducted at 320, 340 and 360degC, the total SCC susceptibility dependence on temperature was small and the IGSCC susceptibility was dependent on the temperature. From these results, the TGSCC susceptibility dependence on temperature was also small. The activation energy of total SCC and IGSCC susceptibility were calculated. (author)

Electrochemical tests for pitting and crevice corrosion susceptibility

International Nuclear Information System (INIS)

Postlethwaite, J.

1983-01-01

Passive metals are being considered as container materials for the disposal of nuclear waste by deep burial. Localized corrosion is a potential problem and electrochemical techniques have an important role in the assessment of the susceptibility of these container materials to crevice and pitting corrosion. This paper critically reviews both the theoretical background and the experimental details of the electrochemical test methods presently used in both industrial and scientific studies of localized corrosion in both halide and non-halide solutions and identifies those areas where theory and experimental behaviour are in agreement and those areas for which there is neither well established theory nor an experimental test method

Can disc diffusion susceptibility tests assess the antimicrobial activity of engineered nanoparticles?

NARCIS (Netherlands)

Kourmouli, A.; Valenti, M.; van Rijn, E.; Beaumont, H.J.E.; Kalantzi, Olga Ioanna; Schmidt-Ott, A.; Biskos, G.

2018-01-01

The use of disc diffusion susceptibility tests to determine the antibacterial activity of engineered nanoparticles (ENPs) is questionable because their low diffusivity practically prevents them from penetrating through the culture media. In this study, we investigate the ability of such a test,

Identification and Antimicrobial Susceptibility Testing of Anaerobic Bacteria: Rubik's Cube of Clinical Microbiology?

Science.gov (United States)

Gajdács, Márió; Spengler, Gabriella; Urbán, Edit

2017-11-07

Anaerobic bacteria have pivotal roles in the microbiota of humans and they are significant infectious agents involved in many pathological processes, both in immunocompetent and immunocompromised individuals. Their isolation, cultivation and correct identification differs significantly from the workup of aerobic species, although the use of new technologies (e.g., matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, whole genome sequencing) changed anaerobic diagnostics dramatically. In the past, antimicrobial susceptibility of these microorganisms showed predictable patterns and empirical therapy could be safely administered but recently a steady and clear increase in the resistance for several important drugs (β-lactams, clindamycin) has been observed worldwide. For this reason, antimicrobial susceptibility testing of anaerobic isolates for surveillance purposes or otherwise is of paramount importance but the availability of these testing methods is usually limited. In this present review, our aim was to give an overview of the methods currently available for the identification (using phenotypic characteristics, biochemical testing, gas-liquid chromatography, MALDI-TOF MS and WGS) and antimicrobial susceptibility testing (agar dilution, broth microdilution, disk diffusion, gradient tests, automated systems, phenotypic and molecular resistance detection techniques) of anaerobes, when should these methods be used and what are the recent developments in resistance patterns of anaerobic bacteria.

Study on hydrogen assisted cracking susceptibility of HSLA steel by implant test

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Gopa Chakraborty

2016-12-01

Full Text Available DMR-249A is an indigenously developed high strength low alloy steel for Indian ship building industry for making ship-hull and is extensively used in the construction of war ships and submarines. Welding electrodes conforming to SFA 5.5 AWS E8018 C1 has been indigenously developed for welding of this steel using shielded metal arc welding process. In the present study, susceptibility to hydrogen assisted cracking of DMR-249A steel welds made using this electrode has been assessed using implant test. Implant tests were conducted using this electrode at two different levels of diffusible hydrogen, measured using gas chromatography technique. It is observed that both the steel and the welding consumable are not susceptible to hydrogen assisted cracking even with a high diffusible hydrogen level of 9 mL/100g of weld metal. In implant tests, specimen did not fracture even after loading to stress levels higher than the yield strength of the base metal. The good resistance of this steel and the welding consumable, even with high levels of diffusible hydrogen, is attributed to absence of a susceptible microstructure in both the weld metal and heat affected zone. Hence, this study shows that, in the absence of a susceptible microstructure, hydrogen assisted cracking is unlikely to occur even if hydrogen level is high. It also confirms that in welding of DMR-249A with indigenously developed E8018 C1 electrode, hydrogen assisted cracking is not a concern and no preheating is required to avoid it during welding.

WHO global salm-surv external quality assurance system (EQAS): an important step toward improving the quality of Salmonella serotyping and antimicrobial susceptibility testing worldwide

DEFF Research Database (Denmark)

Petersen, A.; Aarestrup, Frank Møller; Angulo, F. J.

2002-01-01

% of the results were correct. For susceptibility testing, 92% of the results were in agreement with the expected results. However, only 78% of the performed tests with the E. coli ATCC 25922 reference strain were within the quality control range specified by National Committee for Clinical Laboratory Standards...... susceptibility testing through international training courses and an External Quality Assurance System (EQAS). In 2000, 44 WHO Global Salm-Surv member laboratories from 35 countries determined the serotype and antimicrobial susceptibility pattern for eight "blinded" Salmonella isolates. For serotyping, 73...... (NCCLS) guidelines. These EQAS results demonstrate the need for further training to improve the performance of some of the laboratories. WHO Global Salm-Surv activities, including international training courses and EQAS, represent an important step toward improving the quality of Salmonella serotyping...

Rapid susceptibility testing and microcolony analysis of Candida spp. cultured and imaged on porous aluminum oxide.

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Colin J Ingham

Full Text Available BACKGROUND: Acquired resistance to antifungal agents now supports the introduction of susceptibility testing for species-drug combinations for which this was previously thought unnecessary. For pathogenic yeasts, conventional phenotypic testing needs at least 24 h. Culture on a porous aluminum oxide (PAO support combined with microscopy offers a route to more rapid results. METHODS: Microcolonies of Candida species grown on PAO were stained with the fluorogenic dyes Fun-1 and Calcofluor White and then imaged by fluorescence microscopy. Images were captured by a charge-coupled device camera and processed by publicly available software. By this method, the growth of yeasts could be detected and quantified within 2 h. Microcolony imaging was then used to assess the susceptibility of the yeasts to amphotericin B, anidulafungin and caspofungin (3.5 h culture, and voriconazole and itraconazole (7 h culture. SIGNIFICANCE: Overall, the results showed good agreement with EUCAST (86.5% agreement; n = 170 and E-test (85.9% agreement; n = 170. The closest agreement to standard tests was found when testing susceptibility to amphotericin B and echinocandins (88.2 to 91.2% and the least good for the triazoles (79.4 to 82.4%. Furthermore, large datasets on population variation could be rapidly obtained. An analysis of microcolonies revealed subtle effects of antimycotics on resistant strains and below the MIC of sensitive strains, particularly an increase in population heterogeneity and cell density-dependent effects of triazoles. Additionally, the method could be adapted to strain identification via germ tube extension. We suggest PAO culture is a rapid and versatile method that may be usefully adapted to clinical mycology and has research applications.

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....../spot) as the inoculum and 72 h as the incubation time. A modest inoculum effect was noted for amoxicillin and metronidazole. By the methodology derived from our preliminary study, the susceptibilities of 230 H. pylori strains to six antibiotics were subsequently determined. The results were generally in accord...... with those of others, and apart from metronidazole, the MIC of which for approximately 25% of the strains tested was >8 microg/ml, resistance was low in Denmark. The situation might, however, quickly change when and if the number of indications for antibiotic therapy for H. pylori infections increase...

Children's differential susceptibility to parenting : An experimental test of “for better and for worse”

NARCIS (Netherlands)

Slagt, Meike; Dubas, Judith Semon; van Aken, Marcel; Ellis, Bruce J.; Dekovic, Maja

2017-01-01

Differential susceptibility theory proposes that a subset of individuals exist who display enhanced susceptibility to both negative (risk-promoting) and positive (development-enhancing) environments. This experiment represents the first attempt to directly test this assumption by exposing children

Vaspar broth-disk procedure for antibiotic susceptibility testing of anaerobic bacteria.

OpenAIRE

West, S E; Wilkins, T D

1980-01-01

A modification of the Wilkins-Thiel broth-disk procedure for antibiotic susceptibility testing of anaerobic bacteria is described. This method utilizes an aerobically prepared medium overlaid with molten vaspar. Specialized anaerobic techniques or prereduced media are not required.

In Vitro Antibiotic Susceptibilities of Burkholderia mallei (Causative Agent of Glanders) Determined by Broth Microdilution and E-Test

Science.gov (United States)

Heine, Henry S.; England, Marilyn J.; Waag, David M.; Byrne, W. Russell

2001-01-01

In vitro susceptibilities to 28 antibiotics were determined for 11 strains of Burkholderia mallei by the broth microdilution method. The B. mallei strains demonstrated susceptibility to aminoglycosides, macrolides, quinolones, doxycycline, piperacillin, ceftazidime, and imipenem. For comparison and evaluation, 17 antibiotic susceptibilities were also determined by the E-test. E-test values were always lower than the broth dilution values. Establishing and comparing antibiotic susceptibilities of specific B. mallei strains will provide reference information for assessing new antibiotic agents. PMID:11408233

[Confirming the Utility of RAISUS Antifungal Susceptibility Testing by New-Software].

Science.gov (United States)

Ono, Tomoko; Suematsu, Hiroyuki; Sawamura, Haruki; Yamagishi, Yuka; Mikamo, Hiroshige

2017-08-15

Clinical and Laboratory Standards Institute (CLSI) methods for susceptibility tests of yeast are used in Japan. On the other hand, the methods have some disadvantage; 1) reading at 24 and 48 h, 2) using unclear scale, approximately 50% inhibition, to determine MICs, 3) calculating trailing growth and paradoxical effects. These makes it difficult to test the susuceptibility for yeasts. Old software of RAISUS, Ver. 6.0 series, resolved problem 1) and 2) but did not resolve problem 3). Recently, new software of RAISUS, Ver. 7.0 series, resolved problem 3). We confirmed that using the new software made it clear whether all these issue were settled or not. Eighty-four Candida isolated from Aichi Medical University was used in this study. We compared the MICs obtained by using RAISUS antifungal susceptibility testing of yeasts RSMY1, RSMY1, with those obtained by using ASTY. The concordance rates (±four-fold of MICs) between the MICs obtained by using ASTY and RSMY1 with the new software were more than 90%, except for miconazole (MCZ). The rate of MCZ was low, but MICs obtained by using CLSI methods and Yeast-like Fungus DP 'EIKEN' methods, E-DP, showed equivalent MICs of RSMY1 using the new software. The frequency of skip effects on RSMY1 using the new software markedly decreased relative to RSMY1 using the old software. In case of showing trailing growth, the new software of RAISUS made it possible to choice the correct MICs and to put up the sign of trailing growth on the result screen. New software of RAISUS enhances its usability and the accuracy of MICs. Using automatic instrument to determine MICs is useful to obtain objective results easily.

Genetic Testing for TMEM154 Mutations Associated with Lentivirus Susceptibility in Sheep

Science.gov (United States)

Petrik, Dustin T.; Simpson, Barry; Kijas, James W.; Clawson, Michael L.; Chitko-McKown, Carol G.; Harhay, Gregory P.; Leymaster, Kreg A.

2013-01-01

In sheep, small ruminant lentiviruses cause an incurable, progressive, lymphoproliferative disease that affects millions of animals worldwide. Known as ovine progressive pneumonia virus (OPPV) in the U.S., and Visna/Maedi virus (VMV) elsewhere, these viruses reduce an animal’s health, productivity, and lifespan. Genetic variation in the ovine transmembrane protein 154 gene (TMEM154) has been previously associated with OPPV infection in U.S. sheep. Sheep with the ancestral TMEM154 haplotype encoding glutamate (E) at position 35, and either form of an N70I variant, were highly-susceptible compared to sheep homozygous for the K35 missense mutation. Our current overall aim was to characterize TMEM154 in sheep from around the world to develop an efficient genetic test for reduced susceptibility. The average frequency of TMEM154 E35 among 74 breeds was 0.51 and indicated that highly-susceptible alleles were present in most breeds around the world. Analysis of whole genome sequences from an international panel of 75 sheep revealed more than 1,300 previously unreported polymorphisms in a 62 kb region containing TMEM154 and confirmed that the most susceptible haplotypes were distributed worldwide. Novel missense mutations were discovered in the signal peptide (A13V) and the extracellular domains (E31Q, I74F, and I102T) of TMEM154. A matrix-assisted laser desorption/ionization–time-of flight mass spectrometry (MALDI-TOF MS) assay was developed to detect these and six previously reported missense and two deletion mutations in TMEM154. In blinded trials, the call rate for the eight most common coding polymorphisms was 99.4% for 499 sheep tested and 96.0% of the animals were assigned paired TMEM154 haplotypes (i.e., diplotypes). The widespread distribution of highly-susceptible TMEM154 alleles suggests that genetic testing and selection may improve the health and productivity of infected flocks. PMID:23408992

Genetic testing for TMEM154 mutations associated with lentivirus susceptibility in sheep.

Directory of Open Access Journals (Sweden)

Michael P Heaton

Full Text Available In sheep, small ruminant lentiviruses cause an incurable, progressive, lymphoproliferative disease that affects millions of animals worldwide. Known as ovine progressive pneumonia virus (OPPV in the U.S., and Visna/Maedi virus (VMV elsewhere, these viruses reduce an animal's health, productivity, and lifespan. Genetic variation in the ovine transmembrane protein 154 gene (TMEM154 has been previously associated with OPPV infection in U.S. sheep. Sheep with the ancestral TMEM154 haplotype encoding glutamate (E at position 35, and either form of an N70I variant, were highly-susceptible compared to sheep homozygous for the K35 missense mutation. Our current overall aim was to characterize TMEM154 in sheep from around the world to develop an efficient genetic test for reduced susceptibility. The average frequency of TMEM154 E35 among 74 breeds was 0.51 and indicated that highly-susceptible alleles were present in most breeds around the world. Analysis of whole genome sequences from an international panel of 75 sheep revealed more than 1,300 previously unreported polymorphisms in a 62 kb region containing TMEM154 and confirmed that the most susceptible haplotypes were distributed worldwide. Novel missense mutations were discovered in the signal peptide (A13V and the extracellular domains (E31Q, I74F, and I102T of TMEM154. A matrix-assisted laser desorption/ionization-time-of flight mass spectrometry (MALDI-TOF MS assay was developed to detect these and six previously reported missense and two deletion mutations in TMEM154. In blinded trials, the call rate for the eight most common coding polymorphisms was 99.4% for 499 sheep tested and 96.0% of the animals were assigned paired TMEM154 haplotypes (i.e., diplotypes. The widespread distribution of highly-susceptible TMEM154 alleles suggests that genetic testing and selection may improve the health and productivity of infected flocks.

Development of an Antimicrobial Susceptibility Testing Method Suitable for Performing During Space Flight

Science.gov (United States)

Jorgensen, James H.; Skweres, Joyce A.; Mishra S. K.; McElmeel, M. Letticia; Maher, Louise A.; Mulder, Ross; Lancaster, Michael V.; Pierson, Duane L.

1997-01-01

Very little is known regarding the affects of the microgravity environment of space flight upon the action of antimicrobial agents on bacterial pathogens. This study was undertaken to develop a simple method for conducting antibacterial susceptibility tests during a Space Shuttle mission. Specially prepared susceptibility test research cards (bioMerieux Vitek, Hazelwood, MO) were designed to include 6-11 serial two-fold dilutions of 14 antimicrobial agents, including penicillins, cephalosporins, a Beta-lactamase inhibitor, vancomycin, erythromycin, tetracycline, gentamicin, ciprofloxacin, and trimethoprim/sulfamethoxazole. Minimal inhibitory concentrations (MICS) of the drugs were determined by visual reading of color endpoints in the Vitek research cards made possible by incorporation of a colorimetric growth indicator (alamarBlue(Trademark), Accumed International, Westlake, OH). This study has demonstrated reproducible susceptibility results when testing isolates of Staphylococcus aurezis, Group A Streptococcus, Enterococcusfaecalis, Escherichia coli (beta-lactamase positive and negative strains), Klebsiella pneumoniae, Enterobacter cloacae, and Pseudomoiias aeruginosa. In some instances, the MICs were comparable to those determined using a standard broth microdilution method, while in some cases the unique test media and format yielded slightly different values, that were themselves reproducible. The proposed in-flight experiment will include inoculation of the Vitek cards on the ground prior to launch of the Space Shuttle, storage of inoculated cards at refrigeration temperature aboard the Space Shuttle until experiment initiation, then incubation of the cards for 18-48 h prior to visual interpretation of MICs by the mission's astronauts. Ground-based studies have shown reproducible MICs following storage of inoculated cards for 7 days at 4-8 C to accommodate the mission's time schedule and the astronauts' activities. For comparison, ground-based control

Comparison of Rosco Neo-Sensitabs with Oxoid paper disks in EUCAST disk diffusion antimicrobial susceptibility testing on Mueller-Hinton agar

DEFF Research Database (Denmark)

Justesen, U S; Acar, Ziyap; Olsson, K

2013-01-01

This study compared Neo-Sensitabs with Oxoid paper disks using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) disk diffusion antimicrobial susceptibility test on Mueller-Hinton agar. The EUCAST-recommended quality control strains (Escherichia coli ATCC 25922, Pseudomonas...... paper disks for EUCAST disk diffusion antimicrobial susceptibility testing on Mueller-Hinton agar....

Rapid antimicrobial susceptibility testing of clinical isolates by digital time-lapse microscopy

DEFF Research Database (Denmark)

Fredborg, M; Rosenvinge, F S; Spillum, E

2015-01-01

(168 antimicrobial agent-organism combinations) demonstrated 3.6 % minor, no major and 1.2 % very major errors of the oCelloScope system compared to conventional susceptibility testing, as well as a rapid and correct phenotypic detection of strains with methicillin-resistant Staphylococcus aureus (MRSA......-to-result, enabling same-day targeted antimicrobial therapy, facilitating antibiotic stewardship and better patient management. A full-scale validation of the oCelloScope system including more isolates is necessary to assess the impact of using it for AST....

Rapid, automated, nonradiometric susceptibility testing of Mycobacterium tuberculosis complex to four first-line antituberculous drugs used in standard short-course chemotherapy

DEFF Research Database (Denmark)

Johansen, Isik Somuncu; Thomsen, Vibeke Østergaard; Marjamäki, Merja

2004-01-01

The increasing prevalence of drug-resistant tuberculosis necessitates rapid and accurate susceptibility testing. The nonradiometric BACTEC Mycobacteria Growth Indicator Tube 960 (MGIT) system for susceptibility testing was evaluated on 222 clinical Mycobacterium tuberculosis complex isolates...... for isoniazid, rifampin, and ethambutol. Fifty-seven of the isolates were tested for pyrazinamide. Results were compared to those of radiometric BACTEC 460 system and discrepancies were resolved by the agar proportion method. We found an overall agreement of 99.0% for isoniazid, 99.5% for rifampin, 98.......2% for ethambutol, and 100% for pyrazinamide. After resolution of discrepancies, MGIT yielded no false susceptibility for rifampin and isoniazid. Although turnaround times were comparable, MGIT provides an advantage as inoculation can be done on any weekday as the growth is monitored automatically. The automated...

En Route towards European Clinical breakpoints for veterinary antimicrobial susceptibility testing

NARCIS (Netherlands)

Toutain, Pierre Louis; Bousquet-Mélou, Alain; Damborg, Peter; Ferran, Aude A.; Mevius, Dik; Pelligand, Ludovic; Veldman, Kees T.; Lees, Peter

2017-01-01

VetCAST is the EUCAST sub-committee for Veterinary Antimicrobial Susceptibility Testing. Its remit is to define clinical breakpoints (CBPs) for antimicrobial drugs (AMDs) used in veterinary medicine in Europe. This position paper outlines the procedures and reviews scientific options to solve

Ertapenem susceptibility of extended spectrum beta-lactamase-producing organisms

Directory of Open Access Journals (Sweden)

Selby Edward B

2007-06-01

Full Text Available Abstract Background Infections caused by multiply drug resistant organisms such as extended spectrum beta-lactamase (ESBL-producing Escherichia coli and Klebsiella pneumoniae are increasing. Carbapenems (imipenem and meropenem are the antibiotics commonly used to treat these agents. There is limited clinical data regarding the efficacy of the newest carbapenem, ertapenem, against these organisms. Ertapenem susceptibility of ESBL-producing E. coli and K. pneumoniae clinical isolates were evaluated and compared to imipenem to determine if imipenem susceptibility could be used as a surrogate for ertapenem susceptibility. Methods 100 ESBL isolates (n = 34 E. coli and n = 66 K. pneumoniae collected from 2005–2006 clinical specimens at WRAMC were identified and tested for susceptibility by Vitek Legacy [bioMerieux, Durham, NC]. Ertapenem susceptibility was performed via epsilometer test (E-test [AB Biodisk, Solna, Sweden]. Results 100% of ESBL isolates tested were susceptible to ertapenem. 100% of the same isolates were also susceptible to imipenem. Conclusion These results, based on 100% susceptibility, suggest that ertapenem may be an alternative to other carbapenems for the treatment of infections caused by ESBL-producing E. coli and K. pneumoniae. Clinical outcomes studies are needed to determine if ertapenem is effective for the treatment of infection caused by these organisms. However, due to lack of resistant isolates, we are unable to conclude whether imipenem susceptibility accurately predicts ertapenem susceptibility.

Optimization and evaluation of Flexicult® Vet for detection, identification and antimicrobial susceptibility testing of bacterial uropathogens in small animal veterinary practice.

Science.gov (United States)

Guardabassi, Luca; Hedberg, Sandra; Jessen, Lisbeth Rem; Damborg, Peter

2015-10-26

Urinary tract infection (UTI) is a common reason for antimicrobial prescription in dogs and cats. The objective of this study was to optimize and evaluate a culture-based point-of-care test for detection, identification and antimicrobial susceptibility testing of bacterial uro-pathogens in veterinary practice. Seventy-two urine samples from dogs and cats with suspected UTI presenting to seven veterinary facilities were used by clinical staff and an investigator to estimate sensitivity and specificity of Flexicult Vet A compared to laboratory reference standards for culture and susceptibility testing. Subsequently, the test was modified by inclusion of an oxacillin-containing compartment for detection of methicillin-resistant staphylococci. The performance of the modified product (Flexicult Vet B) for susceptibility testing was evaluated in vitro using a collection of 110 clinical isolates. Bacteriuria was reported by the laboratory in 25 (35 %) samples from the field study. The sensitivity and specificity of Flexicult Vet A for detection of bacteriuria were 83 and 100 %, respectively. Bacterial species were correctly identified in 53 and 100 % of the positive samples by clinical staff and the investigator, respectively. The susceptibility results were interpreted correctly by clinical staff for 70 % of the 94 drug-strain combinations. Higher percentages of correct interpretation were observed when the results were interpreted by the investigator in both the field (76 %) and the in vitro study (94 %). The most frequent errors were false resistance to β-lactams (ampicillin, amoxicillin-clavulanate and cephalotin) in Escherichia coli for Flexicult Vet A, and false amoxicillin-clavulanate resistance in E. coli and false ampicillin susceptibility in Staphylococcus pseudintermedius for Flexicult Vet B. The latter error can be prevented by categorizing staphylococcal strains growing in the oxacillin compartment as resistant to all β-lactams. Despite the

Change of antibiotic susceptibility testing guidelines from CLSI to EUCAST: influence on cumulative hospital antibiograms.

Directory of Open Access Journals (Sweden)

Aline Wolfensberger

Full Text Available OBJECTIVE: We studied whether the change in antibiotic susceptibility testing (AST guidelines from CLSI to EUCAST influenced cumulative antibiograms in a tertiary care hospital in Switzerland. METHODS: Antibiotic susceptibilities of non-duplicate isolates collected within a one-year period before (period A and after (period B changing AST interpretation from CLSI 2009 to EUCAST 1.3 (2011 guidelines were analysed. In addition, period B isolates were reinterpreted according to the CLSI 2009, CLSI 2013 and EUCAST 3.1 (2013 guidelines. RESULTS: The majority of species/drug combinations showed no differences in susceptibility rates comparing periods A and B. However, in some gram-negative bacilli, decreased susceptibility rates were observed when comparing CLSI 2009 with EUCAST 1.3 within period B: Escherichia coli / cefepime, 95.8% (CLSI 2009 vs. 93.1% (EUCAST 1.3, P=0.005; Enterobacter cloacae / cefepime, 97.0 (CLSI 2009 vs. 90.5% (EUCAST 1.3, P=0.012; Pseudomonas aeruginosa / meropenem, 88.1% (CLSI 2009 vs. 78.3% (EUCAST 1.3, P=0.002. These differences were still evident when comparing susceptibility rates according to the CLSI 2013 guideline with EUCAST 3.1 guideline. For P. aeruginosa and imipenem, a trend towards a lower antibiotic susceptibility rate in ICUs compared to general wards turned into a significant difference after the change to EUCAST: 87.9% vs. 79.8%, P=0.08 (CLSI 2009 and 86.3% vs. 76.8%, P=0.048 (EUCAST 1.3. CONCLUSIONS: The change of AST guidelines from CLSI to EUCAST led to a clinically relevant decrease of susceptibility rates in cumulative antibiograms for defined species/drug combinations, particularly in those with considerable differences in clinical susceptibility breakpoints between the two guidelines.

Identification and Antimicrobial Susceptibility Testing of Anaerobic Bacteria: Rubik’s Cube of Clinical Microbiology?

Science.gov (United States)

Gajdács, Márió; Spengler, Gabriella; Urbán, Edit

2017-01-01

Anaerobic bacteria have pivotal roles in the microbiota of humans and they are significant infectious agents involved in many pathological processes, both in immunocompetent and immunocompromised individuals. Their isolation, cultivation and correct identification differs significantly from the workup of aerobic species, although the use of new technologies (e.g., matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, whole genome sequencing) changed anaerobic diagnostics dramatically. In the past, antimicrobial susceptibility of these microorganisms showed predictable patterns and empirical therapy could be safely administered but recently a steady and clear increase in the resistance for several important drugs (β-lactams, clindamycin) has been observed worldwide. For this reason, antimicrobial susceptibility testing of anaerobic isolates for surveillance purposes or otherwise is of paramount importance but the availability of these testing methods is usually limited. In this present review, our aim was to give an overview of the methods currently available for the identification (using phenotypic characteristics, biochemical testing, gas-liquid chromatography, MALDI-TOF MS and WGS) and antimicrobial susceptibility testing (agar dilution, broth microdilution, disk diffusion, gradient tests, automated systems, phenotypic and molecular resistance detection techniques) of anaerobes, when should these methods be used and what are the recent developments in resistance patterns of anaerobic bacteria. PMID:29112122

Antimicrobial susceptibility testing of rapidly growing mycobacteria by microdilution - Experience of a tertiary care centre

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Set R

2010-01-01

Full Text Available Purpose: The objective of the study was to perform antimicrobial susceptibility testing of rapidly growing mycobacteria (RGM isolated from various clinically suspected cases of extrapulmonary tuberculosis, from January 2007 to April 2008, at a tertiary care centre in Mumbai. Materials and Methods: The specimens were processed for microscopy and culture using the standard procedures. Minimum inhibitory concentrations (MIC were determined by broth microdilution, using Sensititre CA MHBT. Susceptibility testing was also carried out on Mueller Hinton agar by the Kirby Bauer disc diffusion method. Results: Of the 1062 specimens received for mycobacterial cultures, 104 (9.79% grew mycobacteria. Of the mycobacterial isolates, six (5.76% were rapid growers. M. abscessus and M. chelonae appeared to be resistant organisms, with M. chelonae showing intermediate resistance to amikacin and minocycline. However, all the six isolates showed sensitivity to vancomycin and gentamicin by the disc diffusion test. Also all three isolates of M. abscessus were sensitive to piperacillin and erythromycin. Further studies are required to test their sensitivity to these four antimicrobials by using the microbroth dilution test, before they can be prescribed to patients. Conclusions: We wish to emphasize that reporting of rapidly growing mycobacteria from clinical settings, along with their sensitivity patterns, is an absolute need of the hour.

Effect of fuel rod design on SCC susceptibility

International Nuclear Information System (INIS)

Wilson, H.W.; Yoon, K.K.; Baty, D.L.

1979-01-01

Laboratory tests were conducted to compare the relative susceptibility of three different zircaloy cladding types to iodine stress corrosion cracking. Two types of tests were conducted which had different characteristics. A substantial dependency of failure susceptibility on cladding type was noted. The differences in behavior were attributed to one or a combination of three cladding characteristics: cladding crystallographic texture, stress relaxation rates, and cladding inner diameter surface condition. The failure susceptibility was qualitatively consistent with the theoretical predictions of crystallographic texture dependencies. A separate series of tests were performed to quantify the differences in stress relaxation between the material types. Results of an analytical calculation are presented which evaluates the applicability of the test results to in-reactor performance

Susceptibility testing of sequential isolates of Aspergillus fumigatus recovered from treated patients.

NARCIS (Netherlands)

Danaoui, E.; Meletiadis, J.; Tortorano, A.M.; Symoens, F.; Nolard, N.; Viviani, M.A.; Piens, M.A.; Lebeau, B.; Verweij, P.E.; Grillot, R.

2004-01-01

Two-hundred sequential Aspergillus fumigatus isolates recovered from 26 immunocompromised patients with invasive aspergillosis or bronchial colonization were tested for their in vitro susceptibility to posaconazole, itraconazole, voriconazole, terbinafine and amphotericin B. Twenty-one patients were

Genotyping using whole-genome sequencing is a realistic alternative to surveillance based on phenotypic antimicrobial susceptibility testing

DEFF Research Database (Denmark)

Zankari, Ea; Hasman, Henrik; Kaas, Rolf Sommer

2013-01-01

-genome sequencing (WGS) may soon be within reach even for routine surveillance and clinical diagnostics. The aim of this study was to evaluate WGS as a routine tool for surveillance of antimicrobial resistance compared with current phenotypic procedures. Methods: Antimicrobial susceptibility tests were performed...... to the categorizing of isolates as resistant and 2569 as susceptible. Seven cases of disagreement between tested and predicted susceptibility were observed, six of which were related to spectinomycin resistance in Escherichia coli. Correlation between MLST type and resistance profiles was only observed in Salmonella...

Routine disc diffusion antimicrobial susceptibility testing of Clostridium difficile and association with PCR ribotype 027

DEFF Research Database (Denmark)

Holt, H M; Danielsen, T K; Justesen, U S

2015-01-01

Reduced susceptibility to metronidazole and vancomycin in Clostridium difficile has been reported, which emphasises the need for simple antimicrobial susceptibility testing methods. The aim of this study was to apply a published disc diffusion method and zone diameter breakpoint correlates...... the published breakpoint (difficile PCR ribotype 027 isolates had smaller zone...... diameters than non-027 isolates. The disc diffusion method is very simple and inexpensive, and the published zone diameter breakpoints will detect C. difficile isolates with reduced susceptibility to metronidazole and vancomycin....

Evaluation of susceptibility of high strength steels to delayed fracture by using cyclic corrosion test and slow strain rate test

International Nuclear Information System (INIS)

Li Songjie; Zhang Zuogui; Akiyama, Eiji; Tsuzaki, Kaneaki; Zhang Boping

2010-01-01

To evaluate susceptibilities of high strength steels to delayed fracture, slow strain rate tests (SSRT) of notched bar specimens of AISI 4135 with tensile strengths of 1300 and 1500 MPa and boron-bearing steel with 1300 MPa have been performed after cyclic corrosion test (CCT). During SSRT the humidity around the specimen was kept high to keep absorbed diffusible hydrogen. The fracture stresses of AISI 4135 steels decreased with increment of diffusible hydrogen content which increased with CCT cycles. Their delayed fracture susceptibilities could be successfully evaluated in consideration of both influence of hydrogen content on mechanical property and hydrogen entry.

Evaluation of susceptibility of high strength steels to delayed fracture by using cyclic corrosion test and slow strain rate test

Energy Technology Data Exchange (ETDEWEB)

Li Songjie [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Hidian Zone, Beijing 100083 (China); Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Zhang Zuogui [Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Akiyama, Eiji [Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)], E-mail: AKIYAMA.Eiji@nims.go.jp; Tsuzaki, Kaneaki [Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Zhang Boping [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Hidian Zone, Beijing 100083 (China)

2010-05-15

To evaluate susceptibilities of high strength steels to delayed fracture, slow strain rate tests (SSRT) of notched bar specimens of AISI 4135 with tensile strengths of 1300 and 1500 MPa and boron-bearing steel with 1300 MPa have been performed after cyclic corrosion test (CCT). During SSRT the humidity around the specimen was kept high to keep absorbed diffusible hydrogen. The fracture stresses of AISI 4135 steels decreased with increment of diffusible hydrogen content which increased with CCT cycles. Their delayed fracture susceptibilities could be successfully evaluated in consideration of both influence of hydrogen content on mechanical property and hydrogen entry.

Fluoromycobacteriophages for Rapid, Specific, and Sensitive Antibiotic Susceptibility Testing of Mycobacterium tuberculosis

Science.gov (United States)

Piuri, Mariana; Jacobs, William R.; Hatfull, Graham F.

2009-01-01

Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis is of paramount importance as multiple- and extensively- drug resistant strains of M. tuberculosis emerge and spread. We describe here a virus-based assay in which fluoromycobacteriophages are used to deliver a GFP or ZsYellow fluorescent marker gene to M. tuberculosis, which can then be monitored by fluorescent detection approaches including fluorescent microscopy and flow cytometry. Pre-clinical evaluations show that addition of either Rifampicin or Streptomycin at the time of phage addition obliterates fluorescence in susceptible cells but not in isogenic resistant bacteria enabling drug sensitivity determination in less than 24 hours. Detection requires no substrate addition, fewer than 100 cells can be identified, and resistant bacteria can be detected within mixed populations. Fluorescence withstands fixation by paraformaldehyde providing enhanced biosafety for testing MDR-TB and XDR-TB infections. PMID:19300517

Direct nitrate reductase assay versus microscopic observation drug susceptibility test for rapid detection of MDR-TB in Uganda.

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Freddie Bwanga

Full Text Available The most common method for detection of drug resistant (DR TB in resource-limited settings (RLSs is indirect susceptibility testing on Lowenstein-Jensen medium (LJ which is very time consuming with results available only after 2-3 months. Effective therapy of DR TB is therefore markedly delayed and patients can transmit resistant strains. Rapid and accurate tests suitable for RLSs in the diagnosis of DR TB are thus highly needed. In this study we compared two direct techniques--Nitrate Reductase Assay (NRA and Microscopic Observation Drug Susceptibility (MODS for rapid detection of MDR-TB in a high burden RLS. The sensitivity, specificity, and proportion of interpretable results were studied. Smear positive sputum was collected from 245 consecutive re-treatment TB patients attending a TB clinic in Kampala, Uganda. Samples were processed at the national reference laboratory and tested for susceptibility to rifampicin and isoniazid with direct NRA, direct MODS and the indirect LJ proportion method as reference. A total of 229 specimens were confirmed as M. tuberculosis, of these interpretable results were obtained in 217 (95% with either the NRA or MODS. Sensitivity, specificity and kappa agreement for MDR-TB diagnosis was 97%, 98% and 0.93 with the NRA; and 87%, 95% and 0.78 with the MODS, respectively. The median time to results was 10, 7 and 64 days with NRA, MODS and the reference technique, respectively. The cost of laboratory supplies per sample was low, around 5 USD, for the rapid tests. The direct NRA and MODS offered rapid detection of resistance almost eight weeks earlier than with the reference method. In the study settings, the direct NRA was highly sensitive and specific. We consider it to have a strong potential for timely detection of MDR-TB in RLS.

Susceptibility of anaerobic bacteria in Auckland: 1991-1996.

Science.gov (United States)

Shore, K P; Pottumarthy, S; Morris, A J

1999-11-12

To determine the antimicrobial susceptibility of local anaerobic bacteria. The antimicrobial susceptibility of 357 obligate anaerobes collected between 1991 and 1997 was determined by a standard agar dilution method. Isolates tested included Bacteroides spp. 131, Fusobacterium spp. 12, Prevotella spp. 13, Veillonella spp. 5, Clostridium perfringens 27, other Clostridium spp. 29, Propionibacterium spp. 57, Actinomyces spp. 7, other non-sporing gram-positive bacilli 28 and Peptostreptococcus spp. 48. Ten antimicrobials were tested: penicillin, amoxycillin/ clavulanic acid, pipercillin/tazobactam, ceftriaxone, cefoxitin, cefotetan, imipenem, meropenem, clindamycin and metronidazole. Imipenem, pipercillin/tazobactam, meropenem and amoxycillin/clavulanic acid were active against virtually all anaerobes tested. Metronidazole was active against all anaerobic gram-negative bacteria and Clostridium spp., but had variable activity against other anaerobes. Cefoxitin was the most active cephalosporin against Bacteroides spp., with 76%, 64% and 15% of Bacteroides spp. being susceptible to cefoxitin, cefotetan and ceftriaxone, respectively. Penicillin had poor activity against anaerobic gram negative bacilli. Actinomyces and Propionibacterium spp. were susceptible to all antimicrobials tested except metronidazole. Variable results were obtained with other antimicrobial-organism combinations. Comparison of results with data from a previously published survey showed little change in susceptibility except for increased resistance of Bacteroides fragilis to ceftriaxone and Clostridium species (not C perfringens) to clindamycin. Our results update the local susceptibility profile of anaerobic bacteria and may be considered when choosing an antimicrobial agent for prophylaxis or treatment of anaerobic infections.

Can disc diffusion susceptibility tests assess the antimicrobial activity of engineered nanoparticles?

Science.gov (United States)

Kourmouli, Angeliki; Valenti, Marco; van Rijn, Erwin; Beaumont, Hubertus J. E.; Kalantzi, Olga-Ioanna; Schmidt-Ott, Andreas; Biskos, George

2018-03-01

The use of disc diffusion susceptibility tests to determine the antibacterial activity of engineered nanoparticles (ENPs) is questionable because their low diffusivity practically prevents them from penetrating through the culture media. In this study, we investigate the ability of such a test, namely the Kirby-Bauer disc diffusion test, to determine the antimicrobial activity of Au and Ag ENPs having diameters from 10 to 40 nm on Escherichia coli cultures. As anticipated, the tests did not show any antibacterial effects of Au nanoparticles (NPs) as a result of their negligible diffusivity through the culture media. Ag NPs on the other hand exhibited a strong antimicrobial activity that was independent of their size. Considering that Ag, in contrast to Au, dissolves upon oxidation and dilution in aqueous solutions, the apparent antibacterial behavior of Ag NPs is attributed to the ions they release. The Kirby-Bauer method, and other similar tests, can therefore be employed to probe the antimicrobial activity of ENPs related to their ability to release ions rather than to their unique size-dependent properties. [Figure not available: see fulltext.

[Identification and drug susceptibility testing of Mycobacterium thermoresistibile and Mycobacterium elephantis isolated from a cow with mastitis].

Science.gov (United States)

Li, W B; Ji, L Y; Xu, D L; Liu, H C; Zhao, X Q; Wu, Y M; Wan, K L

2018-05-10

Objective: To understand the etiological characteristics and drug susceptibility of Mycobacterium thermoresistibile and Mycobacterium elephantis isolated from a cow with mastitis and provide evidence for the prevention and control of infectious mastitis in cows. Methods: The milk sample was collected from a cow with mastitis, which was pretreated with 4 % NaOH and inoculated with L-J medium for Mycobacterium isolation. The positive cultures were initially identified by acid-fast staining and multi-loci PCR, then Mycobacterium species was identified by the multiple loci sequence analysis (MLSA) with 16S rRNA , hsp65 , ITS and SodA genes. The drug sensitivity of the isolates to 27 antibiotics was tested by alamar blue assay. Results: Two anti-acid stain positive strains were isolated from the milk of a cow with mastitis, which were identified as non- tuberculosis mycobacterium by multi-loci PCR, and multi-loci nucleic acid sequence analysis indicated that one strain was Mycobacterium thermoresistibile and another one was Mycobacterium elephantis . The results of the drug susceptibility test showed that the two strains were resistant to most antibiotics, including rifampicin and isoniazid, but they were sensitive to amikacin, moxifloxacin, levofloxacin, ethambutol, streptomycin, tobramycin, ciprofloxacin and linezolid. Conclusions: Mycobacterium thermoresistibile and Mycobacterium elephantis were isolated in a cow with mastitis and the drug susceptibility spectrum of the pathogens were unique. The results of the study can be used as reference for the prevention and control the infection in cows.

Etest and Sensititre YeastOne Susceptibility Testing of Echinocandins against Candida Species from a Single Center in Austria.

Science.gov (United States)

Aigner, Maria; Erbeznik, Thomas; Gschwentner, Martin; Lass-Flörl, Cornelia

2017-08-01

Candida species were tested for susceptibility to caspofungin, anidulafungin, and micafungin in order to evaluate the roles of Etest and Sensititre YeastOne in antifungal susceptibility testing for daily routines and to survey resistance. A total of 104 Candida species isolates detected from blood cultures were investigated. With EUCAST broth microdilution as the reference method, essential agreement (EA), categorical agreement (CA), very major errors (VME), major errors (ME), and minor (MIN) errors were assessed by reading MICs at 18, 24, and 48 h. By use of EUCAST broth microdilution and species-specific clinical breakpoints (CBPs), echinocandin resistance was not detected during the study period. Using EUCAST CBPs, MIC readings at 24 h for the Etest and Sensititre YeastOne resulted in CA levels of 99% and 93% for anidulafungin and 99% and 97% for micafungin. Using revised CLSI CBPs for caspofungin, CA levels were 92% and 99% for Etest and Sensititre YeastOne. The Etest proved an excellent, easy-to-handle alternative method for testing susceptibility to anidulafungin and micafungin. Due to misclassifications, the Etest is less suitable for testing susceptibility to caspofungin (8% of isolates falsely tested resistant). The CA levels of Sensititre YeastOne were 93% and 97% for anidulafungin and micafungin (24 h) by use of EUCAST CBPs and increased to 100% for both antifungals if CLSI CBPs were applied and to 100% and 99% if Sensititre YeastOne epidemiological cutoff values (ECOFFs) were applied. No one echinocandin could be demonstrated to be superior to another in vitro Since resistance was lacking among our Candida isolates, we cannot derive any recommendation from accurate resistance detection by the Etest and Sensititre YeastOne. Copyright © 2017 American Society for Microbiology.

Susceptibility testing of terbinafine alone and in combination with amphotericin B, itraconazole, or voriconazole against conidia and hyphae of dematiaceous molds.

Science.gov (United States)

Biancalana, Fernanda Simas Corrêa; Lyra, Luzia; Moretti, Maria Luiza; Schreiber, Angélica Zaninelli

2011-12-01

Studies have demonstrated excellent in vivo efficacy of terbinafine combined with other antifungal agents against dematiaceous molds; however, there is a lack of in vitro studies. Most studies evaluated conidia inocula, but susceptibility testing of hyphae could mimic the fungal status in infected tissues and might reflect the therapeutic potential of the agent. We investigated the in vitro susceptibility of terbinafine alone and in combination with amphotericin B, itraconazole, or voriconazole against conidia by microdilution and dynamic measurement of hyphae growth of dematiaceous molds. The MIC values for hyphae were, until 3 dilutions, below the MIC obtained for conidia. The results indicated 100% synergistic interactions between terbinafine and azoles or amphotericin B in all tests, but lower MICs for hyphae. In conclusion, our findings allow us to say that the hyphal form of tested dematiaceous molds showed high susceptibility to all antifungal agents evaluated, alone and in combination with terbinafine. Copyright © 2011 Elsevier Inc. All rights reserved.

Rapid identification and antimicrobial susceptibility testing of positive blood cultures using MALDI-TOF MS and a modification of the standardised disc diffusion test: a pilot study.

LENUS (Irish Health Repository)

Fitzgerald, C

2016-04-27

In an era when clinical microbiology laboratories are under increasing financial pressure, there is a need for inexpensive, yet effective, rapid microbiology tests. The aim of this study was to evaluate a novel modification of standard methodology for the identification and antimicrobial susceptibility testing (AST) of pathogens in positive blood cultures, reducing the turnaround time of laboratory results by 24 h.

Rapid drug susceptibility test of mycobacterium tuberculosis by bioluminescence sensor

Science.gov (United States)

Lu, Bin; Xu, Shunqing; Chen, Zifei; Zhou, Yikai

2001-09-01

With the persisting increase of drug-resistant stains of M. Tuberculosis around the world, rapid and sensitive detection of antibiotic of M. Tuberculosis is becoming more and more important. In the present study, drug susceptibility of M. tuberculosis were detected by recombination mycobacteriophage combined with bioluminescence sensor. It is based on the use of recombination mycobacteriophage which can express firefly luciferase when it infects viable mycobacteria, and can effectively produce quantifiable photon. Meanwhile, in mycobacterium cells treated with active antibiotic, no light is observed. The emitted light is recorded by a bioluminscence sensor, so the result of drug-resistant test can be determined by the naked eye. 159 stains of M. tuberculosis were applied to this test on their resistant to rifampin, streptomycin and isoniazid. It is found that the agreement of this assay with Liewenstein- Jensen slat is: rifampin 95.60 percent, isoniazid 91.82 percent, streptomycin 88.68 percent, which showed that it is a fast and practical method to scene and detect drug resistant of mycobacterium stains.

Choosing the correct empirical antibiotic for urinary tract infection in pediatric: Surveillance of antimicrobial susceptibility pattern of Escherichia coli by E-Test method.

Science.gov (United States)

Sedighi, Iraj; Solgi, Abbas; Amanati, Ali; Alikhani, Mohammad Yousef

2014-12-01

Urinary Tract Infections (UTIs) are of the most common bacterial diseases worldwide. We investigate the antibiotic susceptibility patterns of Escherichia coli (E. coli) strains isolated from pediatric patients with community acquired urinary tract infection (UTI) to find a clinical guidance for choosing a right empirical antibiotic in these patients. In this cross sectional study, 100 urine specimens which were positive for E. coli had been investigated for antibiotics susceptibility pattern. The susceptibility to Co-trimoxazol (25μg), Amikacin (30μg), Ceftriaxone (30μg), Nalidixic Acid (30μg), Cefixime (5μg), and Nitrofurantoin (300μg) tested with Disk diffusion agar and MIC determined with the E-test. Mean age of patients was 38 Months. Girls had greater proportion than boys (74 versus 26%). In Disk diffusion method, 26% of the isolates were susceptible to cotrimoxazole. Susceptibility to amikacin, ceftriaxone, nitrofurantoin, nalidixic acid and cefixime was 94%, 66%, 97%, 62% and 52%, respectively. By E-Test method and according to CLSI criteria susceptibility for co-trimoxazol, amikacin, ceftriaxone and nalidixic acid was 37%, 97%, 67% and 50%, respectively. The highest percentage of agreement between Disk diffusion and E-Test method was found for amikacin (96%) and the lowest percentage for co-trimoxazole (89%). Treatment failure, prolonged or repeated hospitalization, increased costs of care, and increased mortality are some consequence of bacterial resistance in UTIs. Misuse of antibiotics in each geographic location directly affects antibiotic resistance pattern. In the treatment of UTI, proper selection of antimicrobial agents should be relevant to the bacterial susceptibility testing surveillance. According to our results, amikacin as an injectable drug and nitrofurantoin as an oral agent could be used as a drug of choice in our region for children with UTIs.

Ethical issues of genetic susceptibility testing for occupational diseases: opinions of trainees in a high-risk job

NARCIS (Netherlands)

Visser, M. J.; Rhebergen, M. D. F.; Kezic, S.; van Dijk, F. J. H.; Willems, D. L.; Verberk, M. M.

2013-01-01

Genetic research has opened up possibilities for identification of persons with an increased susceptibility for occupational disease. However, regulations considering the ethical issues that are inevitably associated with the use of genetic tests for susceptibility for occupational diseases are

Contributions of culture and antimicrobial susceptibility tests to the retreatment of patients with pulmonary tuberculosis

Directory of Open Access Journals (Sweden)

Bruno Horta Andrade

2013-08-01

Full Text Available Introduction This study evaluated the efficacy of retreatment of pulmonary tuberculosis (TB with regard to treatment outcomes and antimicrobial susceptibility testing (ST profiles. Methods This retrospective cohort study analyzed 144 patients treated at a referral hospital in Brazil. All of them had undergone prior treatment, were smear-positive for TB and received a standardized retreatment regimen. Fisher's 2-tailed exact test and the χ2 test were used; RRs and 95% CIs were calculated using univariate and multivariate binary logistic regression. Results The patients were cured in 84 (58.3% cases. Failure was associated with relapsed treatment and abandonment (n=34. Culture tests were obtained for 103 (71.5% cases; 70 (48.6% had positive results. ST results were available for 67 (46.5% cases; the prevalence of acquired resistance was 53.7%. There were no significant differences between those who achieved or not therapeutic success (p=0.988, despite being sensitive or resistant to 1 or more drugs. Rifampicin resistance was independently associated with therapeutic failure (OR: 4.4, 95% CI:1.12-17.37, p=0.034. For those cases in which cultures were unavailable, a 2nd model without this information was built. In this, return after abandonment was significantly associated with retreatment failure (OR: 3.59, 95% CI:1.17-11.06, p=0.026. Conclusions In this cohort, the general resistance profile appeared to have no influence on treatment outcome, except in cases of rifampicin resistance. The form of reentry was another independent predictor of failure. The use of bacterial culture identification and ST in TB management must be re-evaluated. The recommendations for different susceptibility profiles must also be improved.

Rapid Antimicrobial Susceptibility Testing of Bacillus anthracis, Yersinia pestis, and Burkholderia pseudomallei by Use of Laser Light Scattering Technology.

Science.gov (United States)

Bugrysheva, Julia V; Lascols, Christine; Sue, David; Weigel, Linda M

2016-06-01

Rapid methods to determine antimicrobial susceptibility would assist in the timely distribution of effective treatment or postexposure prophylaxis in the aftermath of the release of bacterial biothreat agents such as Bacillus anthracis, Yersinia pestis, or Burkholderia pseudomallei Conventional susceptibility tests require 16 to 48 h of incubation, depending on the bacterial species. We evaluated a method that is based on laser light scattering technology that measures cell density in real time. We determined that it has the ability to rapidly differentiate between growth (resistant) and no growth (susceptible) of several bacterial threat agents in the presence of clinically relevant antimicrobials. Results were available in 10 h of incubation. Use of laser scattering technology decreased the time required to determine antimicrobial susceptibility by 50% to 75% for B. anthracis, Y. pestis, and B. pseudomallei compared to conventional methods. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Tiamulin activity against fastidious and nonfastidious veterinary and human bacterial isolates: initial development of in vitro susceptibility test methods.

Science.gov (United States)

Jones, Ronald N; Pfaller, Michael A; Rhomberg, Paul R; Walter, Donald H

2002-02-01

Tiamulin is a pleuromutilin derivative used in veterinary practice for the control and specific therapy of infections in swine. This report summarizes studies to establish standardized susceptibility testing methods, interpretive criteria, and reagent details for use in veterinary methods recently developed by the National Committee for Clinical Laboratory Standards (NCCLS) (standards M31-A and M37-A, NCCLS, Wayne, Pa., 1999). A total of 636 fastidious and nonfastidious animal and human pathogens were processed by using media and procedures described by the NCCLS. Tiamulin disk diffusion tests used a 30-microg disk concentration, and the proposed MIC breakpoints corresponding to levels achievable in animal target tissues (lung) were or =32 microg/ml for resistance. Correlate zone diameters for specific nonfastidious species were as follows: for Pasteurella multocida and staphylococci tested on Mueller-Hinton agar, susceptibility at > or =19 mm and resistance at or =16 mm and resistance at or =9 mm) was suggested for veterinary fastidious medium broth and enriched chocolate Mueller-Hinton agar. Absolute categorical agreement between NCCLS dilution and disk diffusion test results with these criteria ranged from 90.5 to 96.2%. Tiamulin susceptibility testing methods appear to be accurate in their categorical classification for indicated species, and their availability will allow immediate testing of animal isolates to guide therapy via appropriate levels of dosing and to monitor the development of resistance for agents in this unique class.

Susceptibility Testing of Medically Important Parasites.

Science.gov (United States)

Genetu Bayih, Abebe; Debnath, Anjan; Mitre, Edward; Huston, Christopher D; Laleu, Benoît; Leroy, Didier; Blasco, Benjamin; Campo, Brice; Wells, Timothy N C; Willis, Paul A; Sjö, Peter; Van Voorhis, Wesley C; Pillai, Dylan R

2017-07-01

In the last 2 decades, renewed attention to neglected tropical diseases (NTDs) has spurred the development of antiparasitic agents, especially in light of emerging drug resistance. The need for new drugs has required in vitro screening methods using parasite culture. Furthermore, clinical laboratories sought to correlate in vitro susceptibility methods with treatment outcomes, most notably with malaria. Parasites with their various life cycles present greater complexity than bacteria, for which standardized susceptibility methods exist. This review catalogs the state-of-the-art methodologies used to evaluate the effects of drugs on key human parasites from the point of view of drug discovery as well as the need for laboratory methods that correlate with clinical outcomes. Copyright © 2017 American Society for Microbiology.

Miniaturized Antimicrobial Susceptibility Test by Combining Concentration Gradient Generation and Rapid Cell Culturing

Directory of Open Access Journals (Sweden)

Samuel C. Kim

2015-10-01

Full Text Available Effective treatment of bacterial infection relies on timely diagnosis and proper prescription of antibiotic drugs. The antimicrobial susceptibility test (AST is one of the most crucial experimental procedures, providing the baseline information for choosing effective antibiotic agents and their dosages. Conventional methods, however, require long incubation times or significant instrumentation costs to obtain test results. We propose a lab-on-a-chip approach to perform AST in a simple, economic, and rapid manner. Our assay platform miniaturizes the standard broth microdilution method on a microfluidic device (20 × 20 mm that generates an antibiotic concentration gradient and delivers antibiotic-containing culture media to eight 30-nL chambers for cell culture. When tested with 20 μL samples of a model bacterial strain (E. coli ATCC 25922 treated with ampicillin or streptomycin, our method allows for the determination of minimum inhibitory concentrations consistent with the microdilution test in three hours, which is almost a factor of ten more rapid than the standard method.

Standard Test Methods for Detecting Susceptibility to Intergranular Corrosion in Wrought, Nickel-Rich, Chromium-Bearing Alloys

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 These test methods cover two tests as follows: 1.1.1 Method A, Ferric Sulfate-Sulfuric Acid Test (Sections 3-10, inclusive)—This test method describes the procedure for conducting the boiling ferric sulfate—50 % sulfuric acid test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to intergranular corrosion (see Terminology G 15), which may be encountered in certain service environments. The uniform corrosion rate obtained by this test method, which is a function of minor variations in alloy composition, may easily mask the intergranular corrosion components of the overall corrosion rate on alloys N10276, N06022, N06059, and N06455. 1.1.2 Method B, Mixed Acid-Oxidizing Salt Test (Sections 11-18, inclusive)—This test method describes the procedure for conducting a boiling 23 % sulfuric + 1.2 % hydrochloric + 1 % ferric chloride + 1 % cupric chloride test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to display a step function increa...

[Drug susceptibility test guided therapy and novel empirical quadruple therapy for Helicobacter pylori infection: a network Meta-analysis].

Science.gov (United States)

Gou, Q Y; Yu, R B; Shi, R H

2017-05-10

Objective: To compare the efficacy and the risk of adverse effect of drug susceptibility test guided therapy and novel empirical quadruple therapy for Helicobacter ( H .) pylori infection. Methods: Literature retrieval was conducted by using major databases. Related papers published up to June 2015 were considered eligible if they were randomized control trials comparing different pharmacological formulations for H. pylori infection and used in a network Meta-analysis and a single rate Meta-analysis to evaluate the relative and absolute rates of H. pylori eradication and the risk of adverse effect. The Jadad score was used to evaluate the methodological quality. Funnel plot was constructed to evaluate the risk of publication bias. Begg's rank correlation test or Egger's regression intercept test was done for the asymmetry of funnel plot. Results: Twenty randomized control trials for the treatment of 6 753 initial treated patients with H. pylori infection were included. Drug susceptibility test guided therapy was significantly superior to concomitant therapy, hybrid therapy, sequential therapy and bismuth quadruple therapy. The culture-based therapy had the highest likelihood of improving clinical efficacy, with lowest risk of adverse effect. Concomitant therapy had the highest probability of causing adverse effect despite its effectiveness. Hybrid therapy and bismuth quadruple therapy were associated with lower risk of adverse effect and higher effectiveness. Conclusion: Drug susceptibility test guided therapy showed superiority to other 4 interventions for H. pylori eradication mentioned above. Hybrid therapy and bismuth quadruple therapy might be applied in the settings where the culture-based strategy is not available.

[Rapid test for detection of susceptibility to cefotaxime in Enterobacteriaceae].

Science.gov (United States)

Jiménez-Guerra, Gemma; Hoyos-Mallecot, Yannik; Rodríguez-Granger, Javier; Navarro-Marí, José María; Gutiérrez-Fernández, José

In this work an "in house" rapid test based on the change in pH that is due to hydrolysis for detecting Enterobacteriaceae susceptible to cefotaxime is evaluated. The strains of Enterobacteriaceae from 1947 urine cultures were assessed using MicroScan panels and the "in house" test. This rapid test includes red phenol solution and cefotaxime. Using MicroScan panels, 499 Enterobacteriaceae isolates were evaluated, which included 27 isolates of Escherichia coli producing extended-spectrum beta-lactamases (ESBL), 16 isolates of Klebsiella pneumoniae ESBL and 1 isolate of Klebsiella oxytoca ESBL. The "in house" test offers the following values: sensitivity 98% and specificity 97%, with negative predictive value 100% and positive predictive value 78%. The "in house" test based on the change of pH is useful in our area for detecting presumptively cefotaxime-resistant Enterobacteriaceae strains. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

A review of the current state of antimicrobial susceptibility test methods for Brachyspira.

Science.gov (United States)

Kulathunga, D G R S; Rubin, J E

2017-06-01

The re-emergence of swine dysentery (Brachyspira-associated muco-haemorrhagic colitis) since the late 2000s has illuminated diagnostic challenges associated with this genus. The methods used to detect, identify, and characterize Brachyspira from clinical samples have not been standardized, and laboratories frequently rely heavily on in-house techniques. Particularly concerning is the lack of standardized methods for determining and interpreting the antimicrobial susceptibility of Brachyspira spp. The integration of laboratory data into a treatment plan is a critical component of prudent antimicrobial usage. Therefore, the lack of standardized methods is an important limitation to the evidence-based use of antimicrobials. This review will focus on describing the methodological limitations and inconsistencies between current susceptibility testing schemes employed for Brachyspira, provide an overview of what we do know about the susceptibility of these organisms, and suggest future directions to improve and standardize diagnostic strategies.

The relationship of motion sickness susceptibility to learned autonomic control for symptom suppression

Science.gov (United States)

Cowings, P. S.; Toscano, W. B.

1982-01-01

Twenty-four men were randomly assigned to four equal groups matched in terms of their Coriolis Sickness Susceptibility Index (CSSI). Two groups of subjects were highly susceptible to motion sickness, and two groups were moderately susceptible. All subjects were given six C551 tests at 5-d intervals. Treatment Groups I (highly susceptible) and II (moderately susceptible) were taught to control their autonomic responses, using a training method called autogenic-feedback training (AFT) before the third, fourth, and fifth CSSI tests. Control groups III (highly susceptible) and IV (moderately susceptible) received no treatment. Results showed that both treatment groups significantly improved performance on CSSI tests after training; neither of the control groups changed significantly. Highly and moderately susceptible subjects in the two treatment groups improved at comparable rates. Highly susceptible control group subjects did not habituate across tests as readily as the moderately susceptible controls.

Mobile evaporator corrosion test results

International Nuclear Information System (INIS)

Rozeveld, A.; Chamberlain, D.B.

1997-05-01

Laboratory corrosion tests were conducted on eight candidates to select a durable and cost-effective alloy for use in mobile evaporators to process radioactive waste solutions. Based on an extensive literature survey of corrosion data, three stainless steel alloys (304L, 316L, AL-6XN), four nickel-based alloys (825, 625, 690, G-30), and titanium were selected for testing. The corrosion tests included vapor phase, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80 degrees C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either open-quotes satisfactoryclose quotes (2-20 mpy) or open-quotes excellentclose quotes (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment

Evaluation of Veterinary-Specific Interpretive Criteria for Susceptibility Testing of Streptococcus equi Subspecies with Trimethoprim-Sulfamethoxazole and Trimethoprim-Sulfadiazine.

Science.gov (United States)

Sadaka, Carmen; Kanellos, Theo; Guardabassi, Luca; Boucher, Joseph; Watts, Jeffrey L

2017-01-01

Antimicrobial susceptibility test results for trimethoprim-sulfadiazine with Streptococcus equi subspecies are interpreted based on human data for trimethoprim-sulfamethoxazole. The veterinary-specific data generated in this study support a single breakpoint for testing trimethoprim-sulfamethoxazole and/or trimethoprim-sulfadiazine with S. equi This study indicates trimethoprim-sulfamethoxazole as an acceptable surrogate for trimethoprim-sulfadiazine with S. equi. Copyright © 2016 Sadaka et al.

Isothermal microcalorimetry for antifungal susceptibility testing of Mucorales, Fusarium spp., and Scedosporium spp.

NARCIS (Netherlands)

Furustrand Tafin, U.; Meis, J.F.G.M.; Trampuz, A.

2012-01-01

We evaluated isothermal microcalorimetry for real-time susceptibility testing of non-Aspergillus molds. MIC and minimal effective concentration (MEC) values of Mucorales (n = 4), Fusarium spp. (n = 4), and Scedosporium spp. (n = 4) were determined by microbroth dilution according to the Clinical

Antifungal susceptibility testing of Candida species isolated from the immunocompromised patients admitted to ten university hospitals in Iran

NARCIS (Netherlands)

Badiee, P.; Badali, H.; Boekhout, T.; Diba, K.; Moghadam, A.G.; Hossaini Nasab, A.; Jafarian, H.; Mohammadi, R.; Mirhendi, H.; Najafzadeh, M.J.; Shamsizadeh, A.; Soltani, J.

2017-01-01

Background Antifungal susceptibility testing is a subject of interest in the field of medical mycology. The aim of the present study were the distributions and antifungal susceptibility patterns of various Candida species isolated from colonized and infected immunocompromised patients admitted to

Correcting a Fundamental Flaw in the Paradigm for Antimicrobial Susceptibility Testing

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Selvi C. Ersoy

2017-06-01

Full Text Available The emergence and prevalence of antibiotic-resistant bacteria are an increasing cause of death worldwide, resulting in a global ‘call to action’ to avoid receding into an era lacking effective antibiotics. Despite the urgency, the healthcare industry still relies on a single in vitro bioassay to determine antibiotic efficacy. This assay fails to incorporate environmental factors normally present during host-pathogen interactions in vivo that significantly impact antibiotic efficacy. Here we report that standard antimicrobial susceptibility testing (AST failed to detect antibiotics that are in fact effective in vivo; and frequently identified antibiotics that were instead ineffective as further confirmed in mouse models of infection and sepsis. Notably, AST performed in media mimicking host environments succeeded in identifying specific antibiotics that were effective in bacterial clearance and host survival, even though these same antibiotics failed in results using standard test media. Similarly, our revised media further identified antibiotics that were ineffective in vivo despite passing the AST standard for clinical use. Supplementation of AST medium with sodium bicarbonate, an abundant in vivo molecule that stimulates global changes in bacterial structure and gene expression, was found to be an important factor improving the predictive value of AST in the assignment of appropriate therapy. These findings have the potential to improve the means by which antibiotics are developed, tested, and prescribed.

[Statistical approach to evaluate the occurrence of out-of acceptable ranges and accuracy for antimicrobial susceptibility tests in inter-laboratory quality control program].

Science.gov (United States)

Ueno, Tamio; Matuda, Junichi; Yamane, Nobuhisa

2013-03-01

To evaluate the occurrence of out-of acceptable ranges and accuracy of antimicrobial susceptibility tests, we applied a new statistical tool to the Inter-Laboratory Quality Control Program established by the Kyushu Quality Control Research Group. First, we defined acceptable ranges of minimum inhibitory concentration (MIC) for broth microdilution tests and inhibitory zone diameter for disk diffusion tests on the basis of Clinical and Laboratory Standards Institute (CLSI) M100-S21. In the analysis, more than two out-of acceptable range results in the 20 tests were considered as not allowable according to the CLSI document. Of the 90 participating laboratories, 46 (51%) experienced one or more occurrences of out-of acceptable range results. Then, a binomial test was applied to each participating laboratory. The results indicated that the occurrences of out-of acceptable range results in the 11 laboratories were significantly higher when compared to the CLSI recommendation (allowable rate laboratory was statistically compared with zero using a Student's t-test. The results revealed that 5 of the 11 above laboratories reported erroneous test results that systematically drifted to the side of resistance. In conclusion, our statistical approach has enabled us to detect significantly higher occurrences and source of interpretive errors in antimicrobial susceptibility tests; therefore, this approach can provide us with additional information that can improve the accuracy of the test results in clinical microbiology laboratories.

.i.Aspergillus viridinutans./i. complex: polyphasic taxonomy, mating behaviour and antifungal susceptibility testing

Czech Academy of Sciences Publication Activity Database

Dudová, Z.; Hubka, V.; Svobodová, L.; Hamal, P.; Nováková, Alena; Matsuzawa, T.; Yaguchi, T.; Kubátová, A.; Kolařík, Miroslav

2013-01-01

Roč. 56, Suppl. 3 (2013), s. 162-163 ISSN 0933-7407. [Trends in Medical Mycology /6./. 11.10.2013-14.10.2013, Copenhagen] Institutional support: RVO:60077344 ; RVO:61388971 Keywords : Aspergillus viridinutans * polyphasic taxonomy * mating behaviour * antifungal susceptibility testing Subject RIV: EE - Microbiology, Virology

Semi Quantitative MALDI TOF for Antimicrobial Susceptibility Testing in Staphylococcus aureus

Science.gov (United States)

2017-08-31

Semi- quantitative MALDI-TOF for antimicrobial susceptibility testing in Staphylococcus 1 aureus 2 3 4 Tucker Maxson,a Cheryl L. Taylor-Howell,a...Timothy D. Minoguea# 5 6 Diagnostic Systems Division, United States Army Medical Research Institute of Infectious 7 Disease, Fort Detrick, MD...USAa 8 9 Running Title: Quantitative MALDI for AST in S. aureus 10 #Address correspondence to Timothy D. Minogue, timothy.d.minogue.civ@mail.mil

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

Quality Control Guidelines for Disk Diffusion and Broth Microdilution Antimicrobial Susceptibility Tests with Seven Drugs for Veterinary Applications

Science.gov (United States)

Odland, Brant A.; Erwin, Meredith E.; Jones, Ronald N.

2000-01-01

This multicenter study proposes antimicrobial susceptibility (MIC and disk diffusion methods) quality control (QC) parameters for seven compounds utilized in veterinary health. Alexomycin, apramycin, tiamulin, tilmicosin, and tylosin were tested by broth microdilution against various National Committee for Clinical Laboratory Standards (NCCLS)-recommended QC organisms (Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Streptococcus pneumoniae ATCC 49619, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853). In addition, disk diffusion zone diameter QC limits were determined for apramycin, enrofloxacin, and premafloxacin by using E. coli ATCC 25922, P. aeruginosa ATCC 27853, and S. aureus ATCC 25923. The results from five or six participating laboratories produced ≥99.0% of MICs and ≥95.0% of the zone diameters within suggested guidelines. The NCCLS Subcommittee for Veterinary Antimicrobial Susceptibility Testing has recently approved these ranges for publication in the next M31 document. PMID:10618141

Are Adolescents with ADHD Interested in Genetic Testing for Nicotine Addiction Susceptibility?

Directory of Open Access Journals (Sweden)

Linda J. Herbert

2010-04-01

Full Text Available It has been well-established that some adolescents diagnosed with attention-deficit/hyperactivity disorder (ADHD are at increased risk for cigarette smoking. Current research on the genetic basis of this association could ultimately translate into genetic tests capable of identifying smoking-prone adolescents with ADHD. In this study we examined 81 ADHD affected adolescents’ (age 13–21 interest in genetic testing for nicotine addiction susceptibility. Fifty-seven percent of adolescents indicated a fair amount of interest or more in testing. Most adolescents indicated that the personal information revealed from testing would be either useful (29% or interesting (37%. Implications for genetically-informed smoking prevention and cessation interventions in high risk adolescents with ADHD are discussed.

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.

Family system characteristics and psychological adjustment to cancer susceptibility genetic testing: a prospective study.

NARCIS (Netherlands)

Oostrom, I.I.H. van; Meijers-Heijboer, H.; Duivenvoorden, H.J.; Brocker-Vriends, A.H.; Asperen, C.J. van; Sijmons, R.H.; Seynaeve, C.; Gool, A.R. van; Klijn, J.G.M.; Tibben, A.

2007-01-01

This study examined prospectively the contribution of family functioning, differentiation to parents, family communication and support from relatives to psychological distress in individuals undergoing genetic susceptibility testing for a known familial pathogenic BRCA1/2 or Hereditary nonpolyposis

Family system characteristics and psychological adjustment to cancer susceptibility genetic testing: a prospective study

NARCIS (Netherlands)

van Oostrom, I.; Meijers-Heijboer, H.; Duivenvoorden, H. J.; Bröcker-Vriends, A. H. J. T.; van Asperen, C. J.; Sijmons, R. H.; Seynaeve, C.; van Gool, A. R.; Klijn, J. G. M.; Tibben, A.

2007-01-01

This study examined prospectively the contribution of family functioning, differentiation to parents, family communication and support from relatives to psychological distress in individuals undergoing genetic susceptibility testing for a known familial pathogenic BRCA1/2 or Hereditary nonpolyposis

Family system characteristics and psychological adjustment to cancer susceptibility genetic testing : a prospective study

NARCIS (Netherlands)

van Oostrom, I.; Meijers-Heijboer, H.; Duivenvoorden, H. J.; Brocker-Vriends, A. H. J. T.; van Asperen, C. J.; Sijmons, R. H.; Seynaeve, C.; Van Gool, A. R.; Klijn, J. G. M.; Tibben, A.

This study examined prospectively the contribution of family functioning, differentiation to parents, family communication and support from relatives to psychological distress in individuals undergoing genetic susceptibility testing for a known familial pathogenic BRCA1/2 or Hereditary nonpolyposis

American Society of Clinical Oncology Policy Statement Update: Genetic and Genomic Testing for Cancer Susceptibility.

Science.gov (United States)

Robson, Mark E; Bradbury, Angela R; Arun, Banu; Domchek, Susan M; Ford, James M; Hampel, Heather L; Lipkin, Stephen M; Syngal, Sapna; Wollins, Dana S; Lindor, Noralane M

2015-11-01

The American Society of Clinical Oncology (ASCO) has long affirmed that the recognition and management of individuals with an inherited susceptibility to cancer are core elements of oncology care. ASCO released its first statement on genetic testing in 1996 and updated that statement in 2003 and 2010 in response to developments in the field. In 2014, the Cancer Prevention and Ethics Committees of ASCO commissioned another update to reflect the impact of advances in this area on oncology practice. In particular, there was an interest in addressing the opportunities and challenges arising from the application of massively parallel sequencing-also known as next-generation sequencing-to cancer susceptibility testing. This technology introduces a new level of complexity into the practice of cancer risk assessment and management, requiring renewed effort on the part of ASCO to ensure that those providing care to patients with cancer receive the necessary education to use this new technology in the most effective, beneficial manner. The purpose of this statement is to explore the challenges of new and emerging technologies in cancer genetics and provide recommendations to ensure their optimal deployment in oncology practice. Specifically, the statement makes recommendations in the following areas: germline implications of somatic mutation profiling, multigene panel testing for cancer susceptibility, quality assurance in genetic testing, education of oncology professionals, and access to cancer genetic services. © 2015 by American Society of Clinical Oncology.

Same day identification and full panel antimicrobial susceptibility testing of bacteria from positive blood culture bottles made possible by a combined lysis-filtration method with MALDI-TOF VITEK mass spectrometry and the VITEK2 system.

Directory of Open Access Journals (Sweden)

Alexandra Machen

Full Text Available Rapid identification and antimicrobial susceptibility testing of microorganisms causing bloodstream infections or sepsis have the potential to improve patient care. This proof-of-principle study evaluates the Lysis-Filtration Method for identification as well as antimicrobial susceptibility testing of bacteria directly from positive blood culture bottles in a clinical setting. A total of 100 non-duplicated positive blood cultures were tested and 1012 microorganism-antimicrobial combinations were assessed. An aliquot of non-charcoal blood culture broth was incubated with lysis buffer briefly before being filtered and washed. Microorganisms recovered from the filter membrane were first identified by using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight VITEK® Mass Spectrometry (VITEK MS. After quick identification from VITEK MS, filtered microorganisms were inoculated to VITEK®2 system for full panel antimicrobial susceptibility testing analysis. Of 100 bottles tested, the VITEK MS resulted in 94.0% correct organism identification to the species level. Compared to the conventional antimicrobial susceptibility testing methods, direct antimicrobial susceptibility testing from VITEK®2 resulted in 93.5% (946/1012 category agreement of antimicrobials tested, with 3.6% (36/1012 minor error, 1.7% (7/1012 major error, and 1.3% (13/1012 very major error of antimicrobials. The average time to identification and antimicrobial susceptibility testing was 11.4 hours by using the Lysis-Filtration method for both VITEK MS and VITEK®2 compared to 56.3 hours by using conventional methods (p<0.00001. Thus, the same-day results of microorganism identification and antimicrobial susceptibility testing directly from positive blood culture can be achieved and can be used for appropriate antibiotic therapy and antibiotic stewardship.

Same Day Identification and Full Panel Antimicrobial Susceptibility Testing of Bacteria from Positive Blood Culture Bottles Made Possible by a Combined Lysis-Filtration Method with MALDI-TOF VITEK Mass Spectrometry and the VITEK2 System

Science.gov (United States)

Machen, Alexandra; Drake, Tim; Wang, Yun F. (Wayne)

2014-01-01

Rapid identification and antimicrobial susceptibility testing of microorganisms causing bloodstream infections or sepsis have the potential to improve patient care. This proof-of-principle study evaluates the Lysis-Filtration Method for identification as well as antimicrobial susceptibility testing of bacteria directly from positive blood culture bottles in a clinical setting. A total of 100 non-duplicated positive blood cultures were tested and 1012 microorganism-antimicrobial combinations were assessed. An aliquot of non-charcoal blood culture broth was incubated with lysis buffer briefly before being filtered and washed. Microorganisms recovered from the filter membrane were first identified by using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight VITEK® Mass Spectrometry (VITEK MS). After quick identification from VITEK MS, filtered microorganisms were inoculated to VITEK®2 system for full panel antimicrobial susceptibility testing analysis. Of 100 bottles tested, the VITEK MS resulted in 94.0% correct organism identification to the species level. Compared to the conventional antimicrobial susceptibility testing methods, direct antimicrobial susceptibility testing from VITEK®2 resulted in 93.5% (946/1012) category agreement of antimicrobials tested, with 3.6% (36/1012) minor error, 1.7% (7/1012) major error, and 1.3% (13/1012) very major error of antimicrobials. The average time to identification and antimicrobial susceptibility testing was 11.4 hours by using the Lysis-Filtration method for both VITEK MS and VITEK®2 compared to 56.3 hours by using conventional methods (p<0.00001). Thus, the same-day results of microorganism identification and antimicrobial susceptibility testing directly from positive blood culture can be achieved and can be used for appropriate antibiotic therapy and antibiotic stewardship. PMID:24551067

Change of antibiotic susceptibility testing guidelines from CLSI to EUCAST: influence on cumulative hospital antibiograms.

Science.gov (United States)

Wolfensberger, Aline; Sax, Hugo; Weber, Rainer; Zbinden, Reinhard; Kuster, Stefan P; Hombach, Michael

2013-01-01

We studied whether the change in antibiotic susceptibility testing (AST) guidelines from CLSI to EUCAST influenced cumulative antibiograms in a tertiary care hospital in Switzerland. Antibiotic susceptibilities of non-duplicate isolates collected within a one-year period before (period A) and after (period B) changing AST interpretation from CLSI 2009 to EUCAST 1.3 (2011) guidelines were analysed. In addition, period B isolates were reinterpreted according to the CLSI 2009, CLSI 2013 and EUCAST 3.1 (2013) guidelines. The majority of species/drug combinations showed no differences in susceptibility rates comparing periods A and B. However, in some gram-negative bacilli, decreased susceptibility rates were observed when comparing CLSI 2009 with EUCAST 1.3 within period B: Escherichia coli / cefepime, 95.8% (CLSI 2009) vs. 93.1% (EUCAST 1.3), P=0.005; Enterobacter cloacae / cefepime, 97.0 (CLSI 2009) vs. 90.5% (EUCAST 1.3), P=0.012; Pseudomonas aeruginosa / meropenem, 88.1% (CLSI 2009) vs. 78.3% (EUCAST 1.3), P=0.002. These differences were still evident when comparing susceptibility rates according to the CLSI 2013 guideline with EUCAST 3.1 guideline. For P. aeruginosa and imipenem, a trend towards a lower antibiotic susceptibility rate in ICUs compared to general wards turned into a significant difference after the change to EUCAST: 87.9% vs. 79.8%, P=0.08 (CLSI 2009) and 86.3% vs. 76.8%, P=0.048 (EUCAST 1.3). The change of AST guidelines from CLSI to EUCAST led to a clinically relevant decrease of susceptibility rates in cumulative antibiograms for defined species/drug combinations, particularly in those with considerable differences in clinical susceptibility breakpoints between the two guidelines.

Polymyxins: Antimicrobial susceptibility concerns and therapeutic options

Directory of Open Access Journals (Sweden)

V Balaji

2011-01-01

Full Text Available The increasing prevalence of multidrug-resistant nosocomial pathogens such as Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae poses a great challenge to the treating physicians. The paucity of newer effective antimicrobials has led to renewed interest in the polymyxin group of drugs, as a last resort for treatment of gram-negative bacterial infections. There is a dearth of information on the pharmacological properties of colistin, leading to difficulties in selecting the right dose, dosing interval, and route of administration for treatment, especially in critically-ill patients. The increasing use of colistin over the last few years necessitates the need for accurate and reliable in vitro susceptibility testing methods. Development of heteroresistant strains as a result of colistin monotherapy is also a growing concern. There is a compelling need from the clinicians to provide options for probable and possible colistin combination therapy for multidrug-resistant bacterial infections in the ICU setting. Newer combination drug synergy determination tests are being developed and reported. There are no standardized recommendations from antimicrobial susceptibility testing reference agencies for the testing and interpretation of these drug combinations. Comparison and analysis of these reported methodologies may help to understand and assist the microbiologist to choose the best method that produces accurate results at the earliest. This will help clinicians to select the appropriate combination therapy. In this era of multidrug resistance it is important for the microbiology laboratory to be prepared, by default, to provide timely synergistic susceptibility results in addition to routine susceptibility, if warranted. Not as a favour or at request, but as a responsibility.

Antifungal susceptibility testing of vulvovaginal Candida species among women attending antenatal clinic in tertiary care hospitals of Peshawar

Directory of Open Access Journals (Sweden)

Khan M

2018-03-01

Full Text Available Maria Khan,1 Jawad Ahmed,2 Amina Gul,3 Aamer Ikram,1 Farida Khurram Lalani1 1Department of Microbiology, Armed Forces Institute of Pathology, National University of Management Sciences, CMH Rawalpindi, Rawalpindi, Pakistan; 2Department of Microbiology, Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan; 3Department of Microbiology, Khyber Medical College, Khyber Medical University, Peshawar, Pakistan Background: Vulvovaginal candidiasis (VVC is considered as a pervasive gynecological problem among women worldwide. Owing to this fact, in the current study, we aimed at assessing the prevalence rate of Candida spp. causing VVC in symptomatic pregnant women and their antifungal susceptibility pattern. Methods: This study was carried out in the tertiary care hospitals of Peshawar during the period of July 1, 2016 to December 31, 2016. The study group included 450 pregnant women in the age group of 17–44 years with symptoms of excessive vaginal discharge, pain and pruritis. In all, 108 pregnant women were culture positive for Candida. Antimicrobial susceptibility testing (AST was conducted on specimens against various azoles and polyene F group of antifungals. Results: Out of 108 Candida spp. isolated from vaginal swabs, there were 45 (41.7% Candida albicans, 18 (16.7% Candida tropicalis, 18 (16.7% Candida krusei, 16 (14.8% Candida glabrata and 11 (10.2% Candida dubliniensis. According to age distribution, 27 years was the mean age. Pregnancy trimester distribution among patients was as follows: 21 (19.4% patients were in their first trimester, 65 (60.2% patients were in their second trimester and 22 (20.4% patients were in the third trimester. Susceptibility of fluconazole was determined as follows: 33.3% of the Candida isolates were sensitive, 4.6% were susceptible dose dependent (SDD and 62% were resistant. Susceptibility of Candida spp. with respect to nystatin in patients with VVC was as follows: 25% were

Rapid detection and E-test antimicrobial susceptibility testing of Vibrio parahaemolyticus isolated from seafood and environmental sources in Malaysia.

Science.gov (United States)

Al-Othrubi, Saleh M; Hanafiah, Alfizah; Radu, Son; Neoh, Humin; Jamal, Rahaman

2011-04-01

To find out the prevalence and antimicrobial susceptibility of Vibrio parahaemolyticus in seafoods and environmental sources. The study was carried out at the Center of Excellence for Food Safety Research, University Putra Malaysia; Universiti Kebangsaan Malaysia; Medical Molecular Biology Institute; and University Kebansaan Malaysia Hospital, Malaysia between January 2006 and August 2008. One hundred and forty-four isolates from 400 samples of seafood (122 isolates) and seawater sources (22 isolates) were investigated for the presence of thermostable direct hemolysin (tdh+) and TDH-related hemolysin (trh+) genes using the standard methods. The E-test method was used to test the antimicrobial susceptibility. The study indicates low occurrence of tdh+ (0.69%) and trh+ isolates (8.3%). None of the isolates tested posses both virulence genes. High sensitivity was observed against tetracycline (98%). The mean minimum inhibitory concentration (MIC) of the isolates toward ampicillin increased from 4 ug/ml in 2004 to 24 ug/ml in 2007. The current study demonstrates a low occurrence of pathogenic Vibrio parahaemolyticus in the marine environment and seafood. Nonetheless, the potential risk of vibrio infection due to consumption of Vibrio parahaemolyticus contaminated seafood in Malaysia should not be neglected.

Development of a tiered and binned genetic counseling model for informed consent in the era of multiplex testing for cancer susceptibility.

Science.gov (United States)

Bradbury, Angela R; Patrick-Miller, Linda; Long, Jessica; Powers, Jacquelyn; Stopfer, Jill; Forman, Andrea; Rybak, Christina; Mattie, Kristin; Brandt, Amanda; Chambers, Rachelle; Chung, Wendy K; Churpek, Jane; Daly, Mary B; Digiovanni, Laura; Farengo-Clark, Dana; Fetzer, Dominique; Ganschow, Pamela; Grana, Generosa; Gulden, Cassandra; Hall, Michael; Kohler, Lynne; Maxwell, Kara; Merrill, Shana; Montgomery, Susan; Mueller, Rebecca; Nielsen, Sarah; Olopade, Olufunmilayo; Rainey, Kimberly; Seelaus, Christina; Nathanson, Katherine L; Domchek, Susan M

2015-06-01

Multiplex genetic testing, including both moderate- and high-penetrance genes for cancer susceptibility, is associated with greater uncertainty than traditional testing, presenting challenges to informed consent and genetic counseling. We sought to develop a new model for informed consent and genetic counseling for four ongoing studies. Drawing from professional guidelines, literature, conceptual frameworks, and clinical experience, a multidisciplinary group developed a tiered-binned genetic counseling approach proposed to facilitate informed consent and improve outcomes of cancer susceptibility multiplex testing. In this model, tier 1 "indispensable" information is presented to all patients. More specific tier 2 information is provided to support variable informational needs among diverse patient populations. Clinically relevant information is "binned" into groups to minimize information overload, support informed decision making, and facilitate adaptive responses to testing. Seven essential elements of informed consent are provided to address the unique limitations, risks, and uncertainties of multiplex testing. A tiered-binned model for informed consent and genetic counseling has the potential to address the challenges of multiplex testing for cancer susceptibility and to support informed decision making and adaptive responses to testing. Future prospective studies including patient-reported outcomes are needed to inform how to best incorporate multiplex testing for cancer susceptibility into clinical practice.Genet Med 17 6, 485-492.

Drug Susceptibility Testing of 31 Antimicrobial Agents on Rapidly Growing Mycobacteria Isolates from China

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Hui Pang

2015-01-01

Full Text Available Objectives. Several species of rapidly growing mycobacteria (RGM are now recognized as human pathogens. However, limited data on effective drug treatments against these organisms exists. Here, we describe the species distribution and drug susceptibility profiles of RGM clinical isolates collected from four southern Chinese provinces from January 2005 to December 2012. Methods. Clinical isolates (73 were subjected to in vitro testing with 31 antimicrobial agents using the cation-adjusted Mueller-Hinton broth microdilution method. The isolates included 55 M. abscessus, 11 M. fortuitum, 3 M. chelonae, 2 M. neoaurum, and 2 M. septicum isolates. Results. M. abscessus (75.34% and M. fortuitum (15.07%, the most common species, exhibited greater antibiotic resistance than the other three species. The isolates had low resistance to amikacin, linezolid, and tigecycline, and high resistance to first-line antituberculous agents, amoxicillin-clavulanic acid, rifapentine, dapsone, thioacetazone, and pasiniazid. M. abscessus and M. fortuitum were highly resistant to ofloxacin and rifabutin, respectively. The isolates showed moderate resistance to the other antimicrobial agents. Conclusions. Our results suggest that tigecycline, linezolid, clofazimine, and cefmetazole are appropriate choices for M. abscessus infections. Capreomycin, sulfamethoxazole, tigecycline, clofazimine, and cefmetazole are potentially good choices for M. fortuitum infections. Our drug susceptibility data should be useful to clinicians.

Antimicrobial Disk Susceptibility Testing of Leptospira spp. Using Leptospira Vanaporn Wuthiekanun (LVW) Agar.

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Wuthiekanun, Vanaporn; Amornchai, Premjit; Langla, Sayan; White, Nicholas J; Day, Nicholas P J; Limmathurotsakul, Direk; Peacock, Sharon J

2015-08-01

Leptospira Vanaporn Wuthiekanun (LVW) agar was used to develop a disk diffusion assay for Leptospira spp. Ten pathogenic Leptospira isolates were tested, all of which were susceptible to 17 antimicrobial agents (amoxicillin/clavulanic acid, amoxicillin, azithromycin, cefoxitin, ceftazidime, ceftriaxone, chloramphenicol, ciprofloxacin, clindamycin, doripenem, doxycycline, gentamicin, linezolid, nitrofurantoin, penicillin, piperacillin/tazobactam, and tetracycline). All 10 isolates had no zone of growth inhibition for four antimicrobials (fosfomycin, nalidixic acid, rifampicin, and trimethoprim/sulfamethoxazole). Of the ten Leptospira, seven had a growth inhibition zone of ≤ 21 mm for aztreonam, the zone diameter susceptibility break point for Enterobacteriaceae. This assay could find utility as a simple screening method during the epidemiological surveillance of antimicrobial resistance in Leptospira spp. © The American Society of Tropical Medicine and Hygiene.

Comparison of Disk Diffusion and E-Test Methods for Doripenem Susceptibility of Nosocomial Acinetobacter Baumannii Strains

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Yesim Cekin

2014-03-01

Full Text Available Aim: Acinetobacter species are amoung the most common two cause of infections isolated from patients of intensive care unit in our hospital. Doripenem which acts by inhibiting cell wall synthesis is resently introduced for use in our country is broad spectrum antibiotic belonging to carbapenems. There are many studies investigating the susceptibility of doripenem of Acinetobacter baumannii which is isolated as a cause of ventilatory associated pneumonia in the literature. We aimed to compare e-test and disc diffusion methods for doripenem susceptibility of acinetobacter baumannii strains as nosocomial infections Acinetobacter baumanni isolates detected as nosocomial infection. Material and Method:. Between January to December, 2009 a total of 94 Acinetobacter baumanni strains isolated from different clinical specimens from intensive care units have been studied for doripenem susceptibility by disc diffusion and E-test methods. Minimal inhibitory consantrations (MIC were accepted as; sensitive %u22641 %u03BCg/ml, intermadiate 2-4 %u03BCg/ml, resistant >4 %u03BCg/ml and diameters of inhibition zone with 10 µg disc; sensitive

Is the psychological impact of genetic testing moderated by support and sharing of test results to family and friends?

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Lapointe, Julie; Dorval, Michel; Noguès, Catherine; Fabre, Roxane; Julian-Reynier, Claire

2013-12-01

Receiving the results of genetic tests for a breast and ovarian cancer susceptibility can be a stressful experience. Here we studied the effects of social support (SS) and the sharing of test results on the psychological impact of BRCA1/2 test result disclosure. We also compared carriers and non-carriers on sharing, SS and psychological impact. Five-hundred and twenty-two unaffected women were followed prospectively for 2 years after receiving their test results. Psychological impact was measured on the impact of event scale. Multivariate multi-level models were used, and all the analyses were stratified depending on mutation status (carriers vs non-carriers). Two weeks after receiving their BRCA1/2 results, carriers had shared their test results less frequently than non-carriers (p test results was not significantly associated with psychological impact. Availability of SS was significantly associated with better psychological adjustment across time among carriers (p importance of SS should be stressed, and possible ways of enlisting people in their entourage for this purpose should be discussed in the context of clinical encounters.

Antimicrobial susceptibility monitoring of mastitis pathogens isolated from acute cases of clinical mastitis in dairy cows across Europe: VetPath results.

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Thomas, Valérie; de Jong, Anno; Moyaert, Hilde; Simjee, Shabbir; El Garch, Farid; Morrissey, Ian; Marion, Hervé; Vallé, Michel

2015-07-01

VetPath is an ongoing pan-European antimicrobial susceptibility monitoring programme collecting pathogens from diseased cattle, pigs and poultry not recently treated with antibiotics. Non-replicate milk samples were collected from cows with acute clinical mastitis in eight countries. Escherichia coli, Staphylococcus aureus and Streptococcus uberis were isolated by standardised methods. Antimicrobial susceptibility was determined in a central laboratory by CLSI broth microdilution methodology; results were interpreted using clinical breakpoints where available. Among E. coli (n=280), resistance to tetracycline (14.3%) and cefapirin (11.1%) were most common. Resistance to other β-lactam antibiotics was absent (ceftiofur) or very low (cefalexin, amoxicillin/clavulanic acid). The MIC90 of enrofloxacin and marbofloxacin was 0.03 and 0.06μg/mL, respectively, with 0.7% of strains displaying a deviating high MIC. Staphylococcus aureus (n=250) were susceptible to most antibiotics tested, although 36.0% were resistant to penicillin G. For other β-lactam antibiotics where a CLSI breakpoint was available, no resistance was detected. Tetracycline resistance was low (5.2%). Streptococcus uberis (n=282) were susceptible to all β-lactam antibiotics, although 29.8% were intermediately susceptible to penicillin G; 18.8% of strains were resistant to erythromycin and 28.7% to tetracycline. This European study shows that bacteria associated with acute clinical mastitis are susceptible to most antibiotics with the exception of penicillin G against S. aureus, and erythromycin and tetracycline against S. uberis. The results of this study should serve as a reference baseline. This work also highlights the urgent need to set additional clinical breakpoints for antibiotics frequently used to treat mastitis. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

In Vitro Susceptibility Testing of Tedizolid against Isolates of Nocardia.

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Brown-Elliott, Barbara A; Wallace, Richard J

2017-12-01

There is a paucity of efficacious antimicrobials (especially oral) against clinically relevant species of Nocardia To date, all species of Nocardia have been susceptible to linezolid, the first commercially available oxazolidinone. Tedizolid is a new oxazolidinone with previously reported improved in vitro and in vivo (intracellular) potency against multidrug-resistant strains of Mycobacterium sp. and Nocardia brasiliensis Using the current Clinical and Laboratory Standards Institute-recommended broth microdilution method, 101 isolates of Nocardia spp., including 29 Nocardia cyriacigeorgica , 17 Nocardia farcinica , 13 Nocardia nova complex, 21 Nocardia brasiliensis , 5 Nocardia pseudobrasiliensis , and 5 Nocardia wallacei isolates and 11 isolates of less common species, were tested for susceptibility to tedizolid and linezolid. For the most common clinically significant species of Nocardia , tedizolid MIC 50 values were 0.25 μg/ml for N. nova complex, N. brasiliensis , N. pseudobrasiliensis , and N. wallacei , compared to linezolid MIC 50 values of 1, 2, 0.5, and 1 μg/ml, respectively. Tedizolid and linezolid MIC 90 values were 2 μg/ml for N. nova complex and N. brasiliensis Tedizolid MIC 50 and MIC 90 values for both N. cyriacigeorgica and N. farcinica were 0.5 μg/ml and 1 μg/ml, respectively, compared to linezolid MIC 50 and MIC 90 values of 2 and 4 μg/ml, respectively. Based on MIC 90 values, this study showed that tedizolid was 2- to 3-fold more active than linezolid in vitro against most common species of Nocardia , with the exception of the N. nova complex and N. brasiliensis , for which values were the same. These results may warrant evaluation of tedizolid as a potential treatment option for Nocardia infections. Copyright © 2017 American Society for Microbiology.

Antimicrobial susceptibility pattern and plasmid-mediated ...

African Journals Online (AJOL)

negative Staphylococci (CoNS) were isolated from clinical samples and isolates subjected to antibiotic susceptibility testing, plasmid curing and plasmid DNA isolation. Result: The highest percentages isolates were recovered from urine samples and ...

Evaluation of a draft standard on performance specifications for health physics instrumentation: results for environmental tests

International Nuclear Information System (INIS)

Kenoyer, J.L.; Swinth, K.L.; Mashburn, K.R.; Selby, J.M.

1984-06-01

Draft ANSI Standard N42.17 on performance specifications for health physics instrumentation is currently being evaluated by the Pacific Northwest Laboratory. Evaluation is performed by testing a cross-section of currently available instruments with testing procedures based on specifications of the standard and then determining the degree of conformance to the various elements of the proposed standard. Data will be presented on the performance of a cross-section of beta-gamma survey instruments under various environmental tests. Test results that will be presented include temperature effects, humidity effects, radio frequency (r.f.) susceptibility, ambient pressure effects, vibration effects, and shock effects. Tests performed to date show that most instruments will meet the temperature, humidity, and ambient pressure tests. A large variability is noted among instruments from the same or different vendors. Preliminary r.f. susceptibility tests have shown large artificial responses at some frequencies for specific instruments. The presentation will also include a discussion of procedures used in the testing and weaknesses identified in the proposed standard

Non-susceptible landslide areas in Italy and in the Mediterranean region

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Marchesini, I.; Ardizzone, F.; Alvioli, M.; Rossi, M.; Guzzetti, F.

2014-08-01

We used landslide information for 13 study areas in Italy and morphometric information obtained from the 3-arcseconds shuttle radar topography mission digital elevation model (SRTM DEM) to determine areas where landslide susceptibility is expected to be negligible in Italy and in the landmasses surrounding the Mediterranean Sea. The morphometric information consisted of the local terrain slope which was computed in a square 3 × 3-cell moving window, and in the regional relative relief computed in a circular 15 × 15-cell moving window. We tested three different models to classify the "non-susceptible" landslide areas, including a linear model (LNR), a quantile linear model (QLR), and a quantile, non-linear model (QNL). We tested the performance of the three models using independent landslide information presented by the Italian Landslide Inventory (Inventario Fenomeni Franosi in Italia - IFFI). Best results were obtained using the QNL model. The corresponding zonation of non-susceptible landslide areas was intersected in a geographic information system (GIS) with geographical census data for Italy. The result determined that 57.5% of the population of Italy (in 2001) was located in areas where landslide susceptibility is expected to be negligible. We applied the QNL model to the landmasses surrounding the Mediterranean Sea, and we tested the synoptic non-susceptibility zonation using independent landslide information for three study areas in Spain. Results showed that the QNL model was capable of determining where landslide susceptibility is expected to be negligible in the validation areas in Spain. We expect our results to be applicable in similar study areas, facilitating the identification of non-susceptible landslide areas, at the synoptic scale.

Evaluation of Local Wheat Cultivars Susceptibility to infection with Black Stem Rust

International Nuclear Information System (INIS)

Batta, Y.A.

2007-01-01

The present study was conducted to assess the susceptibility of seven local wheat cultivars from Palestine to infection with black stem rust caused by Puccinia graminis f. sp. tritici. Two techniques of disease inoculation were applied during bioassays: global inoculation of entire wheat plants with urediospores and localized inoculation with urediospores and localized inoculation with urediospores on wheat leaf-pieces incubated under humid conditions. Susceptibility of tested cultivars was evaluated according to disease scale based on number and size of typical unredial pustules that appeared after inoculation on entire plants or leaf pieces. Results obtained on bioassay of susceptibility and disease rating on entire plants indicated that Anbar, Kamata and Hetiya safra cultivars were the least susceptible to P. g. tritici infection, whereas Debiya beda cultivar was the most susceptible. The other tested cultivars such as Nab-El-Jama, sawda and Senf 870 were moderately susceptible. On leaf-pieces, Anbar and Kamatat were the least susceptible cultivars, whereas Debiya beda and Nab-El-Jamal were the most susceptible cultivars. The other tested cultivars such as Debiya swada, Senf 870 and Hetiya safra were moderately susceptible. Significant reductions were obtained for the size of unredial postules formed on leaf-pieces when inoculated in an unwounded state compared to the wounded indicating the importance of wounds during inoculation. The global results indicated the possibility of using above method of disease inoculating, scaling and rating for evaluation of wheat cultivars susceptibility for the eventual use in breeding program for resistant varieties in Palestine. (author)

Antifungal susceptibility testing of yeast isolated from corneal infections Teste de susceptibilidade a antifúngicos de leveduras isoladas de infecções corneais

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Vera Lucia Degaspare Monte Mascaro

2003-10-01

Full Text Available PURPOSE: To report the antifungal susceptibility profile of yeast isolates obtained from cases of keratitis. METHODS: Susceptibility testing of 15 yeast strains isolated from corneal infections to amphotericin B, fluconazole, itraconazole and ketoconazole was performed using the NCCLS broth microdilution assay. RESULTS: Most episodes of eye infections were caused by Candida albicans. The antifungal drugs tested showed the following minimal inhibitory concentration values against yeast isolates: 0.125-0.5 µg/ml for amphotericin B; 0.125->64.0 µg/ml for fluconazole; 0.015-1.0 µg/ml for itraconazole and 0.015-0.125 µg/ml for ketoconazole. Despite the fact that all Candida isolates were judged to be susceptible to azoles, one isolate showed a minimal inhibitory concentration value significantly higher than a 90% minimal inhibitory concentration of all tested isolates. Rhodotorula rubra was resistant to fluconazole and itraconazole. CONCLUSIONS: Despite the fact that most yeast isolates from corneal infections are usually susceptible to amphotericin B and azoles, they exhibit a wide range of minimal inhibitory concentration values for antifungal drugs. The identification of strains at species level and their susceptibility pattern to antifungal drugs should be considered before determining the concentration to be used in topical antifungal formulations in order to optimize therapeutic response in eye infections.OBJETIVO: Relatar resultados e avaliar a aplicabilidade do teste de suscetibilidade a antifúngicos de leveduras isoladas de infecções corneais oculares. MÉTODOS: Realizou-se teste de suscetibilidade pelo método de microdiluição em caldo, padronizado pelo NCCLS-EUA, em 15 amostras de leveduras de infecções corneanas a anfotericina B, fluconazol, itraconazol e ketoconazol. RESULTADOS: A maioria dos episódios de infecção corneal foi causada por Candida albicans. As drogas antifúngicas testadas exibiram valores de concentra

Same day identification and full panel antimicrobial susceptibility testing of bacteria from positive blood culture bottles made possible by a combined lysis-filtration method with MALDI-TOF VITEK mass spectrometry and the VITEK2 system.

Science.gov (United States)

Machen, Alexandra; Drake, Tim; Wang, Yun F Wayne

2014-01-01

Rapid identification and antimicrobial susceptibility testing of microorganisms causing bloodstream infections or sepsis have the potential to improve patient care. This proof-of-principle study evaluates the Lysis-Filtration Method for identification as well as antimicrobial susceptibility testing of bacteria directly from positive blood culture bottles in a clinical setting. A total of 100 non-duplicated positive blood cultures were tested and 1012 microorganism-antimicrobial combinations were assessed. An aliquot of non-charcoal blood culture broth was incubated with lysis buffer briefly before being filtered and washed. Microorganisms recovered from the filter membrane were first identified by using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight VITEK® Mass Spectrometry (VITEK MS). After quick identification from VITEK MS, filtered microorganisms were inoculated to VITEK®2 system for full panel antimicrobial susceptibility testing analysis. Of 100 bottles tested, the VITEK MS resulted in 94.0% correct organism identification to the species level. Compared to the conventional antimicrobial susceptibility testing methods, direct antimicrobial susceptibility testing from VITEK®2 resulted in 93.5% (946/1012) category agreement of antimicrobials tested, with 3.6% (36/1012) minor error, 1.7% (7/1012) major error, and 1.3% (13/1012) very major error of antimicrobials. The average time to identification and antimicrobial susceptibility testing was 11.4 hours by using the Lysis-Filtration method for both VITEK MS and VITEK®2 compared to 56.3 hours by using conventional methods (pdirectly from positive blood culture can be achieved and can be used for appropriate antibiotic therapy and antibiotic stewardship.

Results from EQAS 2002

DEFF Research Database (Denmark)

Petersen, A.; Aarestrup, Frank Møller; Jensen, A.B.

An international external quality assurance program 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 (WHO GSS). In 2002 a total of 117 laborator......An international external quality assurance program 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 (WHO GSS). In 2002 a total of 117...... laboratories from 67 countries participated. For serotyping, almost 90 % of the results were correct. For susceptibility testing, 91 % of the results were in agreement with the expected results, and 86 % of the performed tests with the reference strain E. coli ATCC 25922 were inside the quality control range...

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

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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.

Relationship between antimicrobial susceptibility of clinical mastitis pathogens and treatment outcome in cows.

Science.gov (United States)

Hoe, Fernanda G H; Ruegg, Pamela L

2005-11-01

To determine whether there was any association between results of in vitro antimicrobial susceptibility testing of pathogens isolated from cows with mild or moderate clinical mastitis and outcome of treatment. Observational study. 133 cows with mild or moderate mastitis in a single quarter. Cows were treated by means of intramammary infusion of pirlimycin (50 mg) in the affected quarter once daily for 2 days; additional intramammary treatments with the same product were administered if the milk continued to appear abnormal. Duration of treatment and days until clinical cure were recorded. Bacterial isolates were tested for antimicrobial susceptibility by means of a broth micro-dilution technique. Environmental streptococci, coliforms, and coagulase-negative Staphylococcus spp were the most commonly isolated pathogens. Duration of treatment and days until clinical cure were not significantly different for cows from which pathogens that were susceptible or resistant to pirlimycin were isolated. Bacteriologic cure rates 14 and 21 days after treatment were not significantly different for cows with mastitis caused by susceptible or resistant bacteria. Similar results were found when data only from cows with mastitis caused by gram-positive isolates were analyzed. In the present study, differences in clinical outcome for cows with mild or moderate mastitis that could be attributed to differences in results of in vitro susceptibility testing were not identified. The use of in vitro susceptibility testing to guide intramammary mastitis treatment cannot be recommended on the basis of results of this study.

Application of Enrofloxacin and Orbifloxacin Disks Approved in Japan for Susceptibility Testing of Representative Veterinary Respiratory Pathogens

Science.gov (United States)

HARADA, Kazuki; USUI, Masaru; ASAI, Tetsuo

2014-01-01

ABSTRACT In this study, susceptibilities of Pasteurella multocida, Mannheimia haemolytica and Actinobacillus pleuropneumoniae to enrofloxacin and orbifloxacin were tested using an agar diffusion method with the commercial disks and a broth microdilution method. Good correlation between the 2 methods for enrofloxacin and orbifloxacin was observed for P. multocida (r = −0.743 and −0.818, respectively), M. haemolytica (r = −0.739 and −0.800, respectively) and A. pleuropneumoniae (r = −0.785 and −0.809, respectively). Based on the Clinical and Laboratory Standards Institute interpretive criteria for enrofloxacin, high-level categorical agreement between the 2 methods was found for P. multocida (97.9%), M. haemolytica (93.8%) and A. pleuropneumoniae (92.0%). Our findings indicate that the tested commercial disks can be applied for susceptibility testing of veterinary respiratory pathogens. PMID:25008965

Proposed quality control guidelines for National Committee for Clinical Laboratory Standards Susceptibility Tests using the veterinary antimicrobial agent tiamulin.

Science.gov (United States)

Pfaller, M A; Jones, R N; Walter, D H

2001-01-01

Quality control guidelines for standardized antimicrobial susceptibility test methods are critical for the continuing accuracy of these clinical tests. In this report, quality control limits were proposed for the veterinary antimicrobial agent tiamulin with minimum inhibitory concentration (MIC) ranges of three or four log(2) dilution steps in two different medium formulations. Disk diffusion zone diameter ranges were proposed for tiamulin tested against Actinobacillus pleuropneumoniae ATCC 27090 (12-18 mm) and Staphylococcus aureus ATCC 25923 (25-32 mm). The data from eight participating laboratories produced 100% of results within proposed MIC limits (8-32 microg/mL), and 95.8-97.0% of zones were found within suggested zone diameter QC guidelines. These proposed QC ranges should be validated by in-use results from veterinary clinical laboratories.

Do sediment type and test durations affect results of laboratory-based, accelerated testing studies of permeable pavement clogging?

Science.gov (United States)

Nichols, Peter W B; White, Richard; Lucke, Terry

2015-04-01

Previous studies have attempted to quantify the clogging processes of Permeable Interlocking Concrete Pavers (PICPs) using accelerated testing methods. However, the results have been variable. This study investigated the effects that three different sediment types (natural and silica), and different simulated rainfall intensities, and testing durations had on the observed clogging processes (and measured surface infiltration rates) of laboratory-based, accelerated PICP testing studies. Results showed that accelerated simulated laboratory testing results are highly dependent on the type, and size of sediment used in the experiments. For example, when using real stormwater sediment up to 1.18 mm in size, the results showed that neither testing duration, nor stormwater application rate had any significant effect on PICP clogging. However, the study clearly showed that shorter testing durations generally increased clogging and reduced the surface infiltration rates of the models when artificial silica sediment was used. Longer testing durations also generally increased clogging of the models when using fine sediment (<300 μm). Results from this study will help researchers and designers better anticipate when and why PICPs are susceptible to clogging, reduce maintenance and extend the useful life of these increasingly common stormwater best management practices. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of Etest and macrodilution broth method for antifungal susceptibility testing of Candida sp strains isolated from oral cavities of AIDS patients

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SILVA Maria do Rosário R.

2002-01-01

Full Text Available A comparison of the Etest and the reference broth macrodilution susceptibility test for fluconazole, ketoconazole, itraconazole and amphotericin B was performed with 59 of Candida species isolated from the oral cavities of AIDS patients. The Etest method was performed according to the manufacturer's instructions, and the reference method was performed according to National Committee for Clinical Laboratory Standards document M27-A guidelines. Our data showed that there was a good correlation between the MICs obtained by the Etest and broth dilution methods. When only the MIC results at ± 2 dilutions for both methods were considered, the agreement rates were 90.4% for itraconazole, ketoconazole and amphotericin B and 84.6% for fluconazole of the C. albicans tested. In contrast, to the reference method, the Etest method classified as susceptible three fluconazole-resistant isolates and one itraconazole-resistant isolate, representing four very major errors. These results indicate that Etest could be considered useful for antifungal sensitivity evaluation of yeasts in clinical laboratories.

Use of matrix-assisted laser desorption ionization-time of flight mass spectrometry for caspofungin susceptibility testing of Candida and Aspergillus species.

Science.gov (United States)

De Carolis, Elena; Vella, Antonietta; Florio, Ada R; Posteraro, Patrizia; Perlin, David S; Sanguinetti, Maurizio; Posteraro, Brunella

2012-07-01

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was evaluated for testing susceptibility to caspofungin of wild-type and fks mutant isolates of Candida and Aspergillus. Complete essential agreement was observed with the CLSI reference method, with categorical agreement for 94.1% of the Candida isolates tested. Thus, MALDI-TOF MS is a reliable and accurate method to detect fungal isolates with reduced caspofungin susceptibility.

21 CFR 866.1640 - Antimicrobial susceptibility test powder.

Science.gov (United States)

2010-04-01

... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Diagnostic Devices § 866.1640 Antimicrobial... clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic...

Susceptibility profiles of Nocardia isolates based on current taxonomy.

Science.gov (United States)

Schlaberg, Robert; Fisher, Mark A; Hanson, Kimberley E

2014-01-01

The genus Nocardia has undergone rapid taxonomic expansion in recent years, and an increasing number of species are recognized as human pathogens. Many established species have predictable antimicrobial susceptibility profiles, but sufficient information is often not available for recently described organisms. Additionally, the effectiveness of sulfonamides as first-line drugs for Nocardia has recently been questioned. This led us to review antimicrobial susceptibility patterns for a large number of molecularly identified clinical isolates. Susceptibility results were available for 1,299 isolates representing 39 different species or complexes, including 11 that were newly described, during a 6-year study period. All tested isolates were susceptible to linezolid. Resistance to trimethoprim-sulfamethoxazole (TMP-SMX) was rare (2%) except among Nocardia pseudobrasiliensis (31%) strains and strains of the N. transvalensis complex (19%). Imipenem susceptibility varied for N. cyriacigeorgica and N. farcinica, as did ceftriaxone susceptibility of the N. nova complex. Resistance to more than one of the most commonly used drugs (amikacin, ceftriaxone, TMP-SMX, and imipenem) was highest for N. pseudobrasiliensis (100%), N. transvalensis complex (83%), N. farcinica (68%), N. puris (57%), N. brasiliensis (51%), N. aobensis (50%), and N. amikacinitolerans (43%). Thus, while antimicrobial resistance can often be predicted, susceptibility testing should still be considered when combination therapy is warranted, for less well characterized species or those with variable susceptibility profiles, and for patients with TMP-SMX intolerance.

A Novel Hypoxia Challenge Test Demonstrates Cardiovascular and Pulmonary Susceptibility to Acrolein Gas in Hypertensive Rats.

Science.gov (United States)

High levels of air pollution increase the risk of cardiovascular morbidity and mortality, especially in susceptible populations including those with hypertension. Stress tests are useful for manifesting latent effects of exposure, particularly at low concentrations, often when no...

Drug Susceptibility Testing of 31 Antimicrobial Agents on Rapidly Growing Mycobacteria Isolates from China.

Science.gov (United States)

Pang, Hui; Li, Guilian; Zhao, Xiuqin; Liu, Haican; Wan, Kanglin; Yu, Ping

2015-01-01

Several species of rapidly growing mycobacteria (RGM) are now recognized as human pathogens. However, limited data on effective drug treatments against these organisms exists. Here, we describe the species distribution and drug susceptibility profiles of RGM clinical isolates collected from four southern Chinese provinces from January 2005 to December 2012. Clinical isolates (73) were subjected to in vitro testing with 31 antimicrobial agents using the cation-adjusted Mueller-Hinton broth microdilution method. The isolates included 55 M. abscessus, 11 M. fortuitum, 3 M. chelonae, 2 M. neoaurum, and 2 M. septicum isolates. M. abscessus (75.34%) and M. fortuitum (15.07%), the most common species, exhibited greater antibiotic resistance than the other three species. The isolates had low resistance to amikacin, linezolid, and tigecycline, and high resistance to first-line antituberculous agents, amoxicillin-clavulanic acid, rifapentine, dapsone, thioacetazone, and pasiniazid. M. abscessus and M. fortuitum were highly resistant to ofloxacin and rifabutin, respectively. The isolates showed moderate resistance to the other antimicrobial agents. Our results suggest that tigecycline, linezolid, clofazimine, and cefmetazole are appropriate choices for M. abscessus infections. Capreomycin, sulfamethoxazole, tigecycline, clofazimine, and cefmetazole are potentially good choices for M. fortuitum infections. Our drug susceptibility data should be useful to clinicians.

Hydrogen embrittlement susceptibility of laser-hardened 4140 steel

Energy Technology Data Exchange (ETDEWEB)

Tsay, L.W.; Lin, Z.W. [Nat. Taiwan Ocean Univ., Keelung (Taiwan). Inst. of Mater. Eng.; Shiue, R.K. [Institute of Materials Sciences and Engineering, National Dong Hwa University, Hualien, Taiwan (Taiwan); Chen, C. [Institute of Materials Sciences and Engineering, National Taiwan University, Taipei, Taiwan (Taiwan)

2000-10-15

Slow strain rate tensile (SSRT) tests were performed to investigate the susceptibility to hydrogen embrittlement of laser-hardened AISI 4140 specimens in air, gaseous hydrogen and saturated H{sub 2}S solution. Experimental results indicated that round bar specimens with two parallel hardened bands on opposite sides along the loading axis (i.e. the PH specimens), exhibited a huge reduction in tensile ductility for all test environments. While circular-hardened (CH) specimens with 1 mm hardened depth and 6 mm wide within the gauge length were resistant to gaseous hydrogen embrittlement. However, fully hardened CH specimens became susceptible to hydrogen embrittlement for testing in air at a lower strain rate. The strength of CH specimens increased with decreasing the depth of hardened zones in a saturated H{sub 2}S solution. The premature failure of hardened zones in a susceptible environment caused the formation of brittle intergranular fracture and the decrease in tensile ductility. (orig.)

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

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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.

Comparison of the Cathra Repliscan II, the AutoMicrobic system Gram-Negative General Susceptibility-Plus Card, and the Micro-Media System Fox Panel for dilution susceptibility testing of gram-negative bacilli.

Science.gov (United States)

Reiber, N E; Kelly, M T; Latimer, J M; Tison, D L; Hysmith, R M

1985-06-01

A comparative evaluation was done to test the accuracy of the Cathra Repliscan II agar dilution system (Diagnostic Equipment, Inc., St. Paul, Minn.), the AutoMicrobic system with Gram-Negative General Susceptibility-Plus Card (Vitek Systems, Inc., Hazelwood, Mo.), and the Micro-Media Fox Panel micro broth dilution system (Micro-Media Systems, Inc., San Jose, Calif.) in determining MICs of 12 antibiotics for 200 gram-negative bacilli. Of the 200 strains tested, 12 isolates did not grow in one of the three systems. The 188 remaining organisms included 158 members of the family Enterobacteriaceae, 20 Pseudomonas spp., 5 Acinetobacter sp., 3 Aeromonas spp., and 2 Vibrio spp. A total of 2,256 organism-antibiotic combinations were analyzed for each system. An MIC was considered correct if two of the three systems were in agreement. When disagreements occurred, correct MICs were determined by the standard agar dilution method. With this criterion, overall agreements of the Cathra Repliscan II system, AutoMicrobic system, and Micro-Media Fox Panel system were 94.7, 94.9, and 95.5%, respectively. Tetracycline (20%), nitrofurantoin (20%), and ampicillin (16%) accounted for 56% of the discrepancies observed. These results indicate that all three systems perform with a high degree of accuracy for susceptibility testing of gram-negative bacilli.

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....... The results showed that B. hyodysenteriae B78(T) ATCC 27164(T) is a suitable quality control strain. This is a first step toward standardization of methods regarding this anaerobe....

Short communication prevalence of susceptibility to etravirine by genotype and phenotype in samples received for routine HIV type 1 resistance testing in the United States.

Science.gov (United States)

Picchio, Gaston; Vingerhoets, Johan; Tambuyzer, Lotke; Coakley, Eoin; Haddad, Mojgan; Witek, James

2011-12-01

Abstract The prevalence of susceptibility to etravirine was investigated among clinical samples submitted for routine clinical testing in the United States using two separate weighted genotypic scoring systems. The presence of etravirine mutations and susceptibility to etravirine by phenotype of clinical samples from HIV-1-infected patients, submitted to Monogram Biosciences for routine resistance testing between June 2008 and June 2009, were analyzed. Susceptibility by genotype was determined using the Monogram and Tibotec etravirine-weighted genotypic scoring systems, with scores of ≤3 and ≤2, respectively, indicating full susceptibility. Susceptibility by phenotype was determined using the PhenoSense HIV assay, with lower and higher clinical cut-offs of 2.9 and 10, respectively. The frequency of individual etravirine mutations and the impact of the K103N mutation on susceptibility to etravirine by genotype were also determined. Among the 5482 samples with ≥1 defined nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations associated with resistance, 67% were classed as susceptible to etravirine by genotype by both scoring systems. Susceptibility to etravirine by phenotype was higher (76%). The proportion of first-generation NNRTI-resistant samples with (n=3598) and without (n=1884) K103N with susceptibility to etravirine by genotype was 77% and 49%, respectively. Among samples susceptible to first-generation NNRTIs (n=9458), >99% of samples were susceptible to etravirine by phenotype (FC <2.9); the remaining samples had FC ≥2.9-10. In summary, among samples submitted for routine clinical testing in the United States, a high proportion of samples with first-generation NNRTI resistance was susceptible to etravirine by genotype and phenotype. A higher proportion of NNRTI-resistant samples with K103N than without was susceptible to etravirine.

Caspofungin Etest susceptibility testing of Candida species

DEFF Research Database (Denmark)

Arendrup, Maiken Cavling; Pfaller, Michael A; Schønheyder, Henrik Carl

2012-01-01

The purpose of this study was to evaluate the performance of caspofungin Etest and the recently revised CLSI breakpoints. A total of 497 blood isolates, of which 496 were wild-type isolates, were included. A total of 65/496 susceptible isolates (13.1%) were misclassified as intermediate (I) or re...

Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Caspofungin Susceptibility Testing of Candida and Aspergillus Species

Science.gov (United States)

De Carolis, Elena; Vella, Antonietta; Florio, Ada R.; Posteraro, Patrizia; Perlin, David S.; Posteraro, Brunella

2012-01-01

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) was evaluated for testing susceptibility to caspofungin of wild-type and fks mutant isolates of Candida and Aspergillus. Complete essential agreement was observed with the CLSI reference method, with categorical agreement for 94.1% of the Candida isolates tested. Thus, MALDI-TOF MS is a reliable and accurate method to detect fungal isolates with reduced caspofungin susceptibility. PMID:22535984

Influence of deformation on SCC susceptibility of austenitic stainless steel in PWR primary water

Energy Technology Data Exchange (ETDEWEB)

Kaneshima, Yoshiari; Totsuka, Nobuo; Nakajima, Nobuo [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2001-09-01

Slow strain rate tests (SSRT) were carried out to evaluate the SCC susceptibility of four types of austenitic stainless steels (SUS304, SUS316, SUS304L and SUS316L) in PWR primary water. The influence of deformation on SCC susceptibility of SUS316 was studied. All types of stainless steel were susceptible to SCC, and the SCC susceptibility varied depending on the steel type. The comparison of the SSRT results and tensile test in air based on the reduction of area measurement showed that the SCC susceptibility increased with increasing the degree of deformation. For explaining the influence of deformation on SCC susceptibility, it is necessary to evaluate both intergranular and transgranular fractures. (author)

Studies on maize inbred lines susceptibility to herbicides

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Stefanović Lidija

2010-01-01

Full Text Available This paper presents the analysis of results obtained during long- term studies on the response of maize inbred lines to herbicides. Under the agroecological conditions of Zemun Polje the response (reaction of maize inbred lines to herbicides of different classes was investigated. Biological tests were performed and some agronomic, morphological, physiological and biochemical parameters were determined when the response of maize inbred lines to herbicides was estimated. The use of active ingredients of herbicides from triazine, acetanilide, thiocarbamate to new chemical groups (sulfonylurea etc., have been resulted in changes in weed suppression and susceptibility of inbred lines. Obtained results show that effects of herbicides on susceptible maize genotypes can be different: they can slowdown the growth and development and affect the plant height; they can also affect the stages of the tassel and ear development and at the end they can reduced grain yield of the tested inbreds. Numerous studies confirmed the existence of differences in susceptibility level of maize genotypes in relation to herbicides. According to gained results the recommendations for growers are made on the possibility of the application of new herbicides in the hybrid seed production.

Rapid identification and susceptibility testing of Candida spp. from positive blood cultures by combination of direct MALDI-TOF mass spectrometry and direct inoculation of Vitek 2.

Science.gov (United States)

Idelevich, Evgeny A; Grunewald, Camilla M; Wüllenweber, Jörg; Becker, Karsten

2014-01-01

Fungaemia is associated with high mortality rates and early appropriate antifungal therapy is essential for patient management. However, classical diagnostic workflow takes up to several days due to the slow growth of yeasts. Therefore, an approach for direct species identification and direct antifungal susceptibility testing (AFST) without prior time-consuming sub-culturing of yeasts from positive blood cultures (BCs) is urgently needed. Yeast cell pellets prepared using Sepsityper kit were used for direct identification by MALDI-TOF mass spectrometry (MS) and for direct inoculation of Vitek 2 AST-YS07 card for AFST. For comparison, MALDI-TOF MS and Vitek 2 testing were performed from yeast subculture. A total of twenty four positive BCs including twelve C. glabrata, nine C. albicans, two C. dubliniensis and one C. krusei isolate were processed. Applying modified thresholds for species identification (score ≥ 1.5 with two identical consecutive propositions), 62.5% of BCs were identified by direct MALDI-TOF MS. AFST results were generated for 72.7% of BCs directly tested by Vitek 2 and for 100% of standardized suspensions from 24 h cultures. Thus, AFST comparison was possible for 70 isolate-antifungal combinations. Essential agreement (minimum inhibitory concentration difference ≤ 1 double dilution step) was 88.6%. Very major errors (VMEs) (false-susceptibility), major errors (false-resistance) and minor errors (false categorization involving intermediate result) amounted to 33.3% (of resistant isolates), 1.9% (of susceptible isolates) and 1.4% providing 90.0% categorical agreement. All VMEs were due to fluconazole or voriconazole. This direct method saved on average 23.5 h for identification and 15.1 h for AFST, compared to routine procedures. However, performance for azole susceptibility testing was suboptimal and testing from subculture remains indispensable to validate the direct finding.

Rapid identification and susceptibility testing of Candida spp. from positive blood cultures by combination of direct MALDI-TOF mass spectrometry and direct inoculation of Vitek 2.

Directory of Open Access Journals (Sweden)

Evgeny A Idelevich

Full Text Available Fungaemia is associated with high mortality rates and early appropriate antifungal therapy is essential for patient management. However, classical diagnostic workflow takes up to several days due to the slow growth of yeasts. Therefore, an approach for direct species identification and direct antifungal susceptibility testing (AFST without prior time-consuming sub-culturing of yeasts from positive blood cultures (BCs is urgently needed. Yeast cell pellets prepared using Sepsityper kit were used for direct identification by MALDI-TOF mass spectrometry (MS and for direct inoculation of Vitek 2 AST-YS07 card for AFST. For comparison, MALDI-TOF MS and Vitek 2 testing were performed from yeast subculture. A total of twenty four positive BCs including twelve C. glabrata, nine C. albicans, two C. dubliniensis and one C. krusei isolate were processed. Applying modified thresholds for species identification (score ≥ 1.5 with two identical consecutive propositions, 62.5% of BCs were identified by direct MALDI-TOF MS. AFST results were generated for 72.7% of BCs directly tested by Vitek 2 and for 100% of standardized suspensions from 24 h cultures. Thus, AFST comparison was possible for 70 isolate-antifungal combinations. Essential agreement (minimum inhibitory concentration difference ≤ 1 double dilution step was 88.6%. Very major errors (VMEs (false-susceptibility, major errors (false-resistance and minor errors (false categorization involving intermediate result amounted to 33.3% (of resistant isolates, 1.9% (of susceptible isolates and 1.4% providing 90.0% categorical agreement. All VMEs were due to fluconazole or voriconazole. This direct method saved on average 23.5 h for identification and 15.1 h for AFST, compared to routine procedures. However, performance for azole susceptibility testing was suboptimal and testing from subculture remains indispensable to validate the direct finding.

Susceptibility of Aeromonas Hydophila Isolates to Antimicrobial Drugs

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Igor Stojanov

2010-05-01

Full Text Available Aeromonas hydrophila is a microorganism widely distributed in nature: in water, soil, food. It is also part of the normal bacterial flora of many animals. As an opportune microorganism it is a secondary biological agent that contributes to the occurrence of a fish disease and its deterioration. Frequently, its presence is an indication of bad zoohygiene and zootechnical conditions in fish ponds. Reduced quality and quantity of feed, mechanical injuries, parasitosis, seasonal oscillation in temperature present some of the factors that produce favorable conditions for bacterial proliferation of aeromonas in fish ponds, so clinical symptoms of the disease occur. Aeromonas is almost always present in clinical isolates and may be unjustly accused for bad health of fish. Antibiotic therapy is applied even when the clinical findings are clear, what certainly effects the susceptibility to chemotherapeutics. The subject of our work was bacteriological examination of the material obtained from the carps with the observed skin changes and the carps without these changes. Also, antimicrobial susceptibility of Aeromonas hydrophila was tested. The aim of this research was to determined the presence of Aeromonas hydrophilia in the carp ponds and to test antibiotic susceptibility. The material consisted of the samples from the fish ponds where the carps were with and without changed skin. The method the isolation of Aeromonas hydrophila was used. The diffusion disk technique was used for testing antibiotic susceptibility. The isolates were tested for their susceptibility to Florephenikol, Flumequine, Olaqindox and Oxitetracycline. The obtained results point that antimicrobial susceptibility was the same regardless of the origin of the samples, i.e. the resistance was the same for both groups of samples (the strains isolated from the fish with skin changes and the strains from fish without changes on skin. The strains were highly resistant: 35% were resistant to

Comparison of M.I.C.E. and Etest with CLSI agar dilution for antimicrobial susceptibility testing against oxacillin-resistant Staphylococcus spp.

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Eloiza H Campana

Full Text Available OBJECTIVE: The main objective of this study was to comparatively evaluate the performance of M.I.C.E. and Etest methodologies to that of agar dilution for determining the antimicrobial susceptibility profile of oxacillin-resistant Staphylococcus spp. METHODS: A total of 100 oxacillin-resistant Staphylococcus spp. isolates were collected from hospitalized patients at a teaching hospital. Antimicrobial susceptibility testing for vancomycin, teicoplanin and linezolid was performed using the reference CLSI agar dilution method (2009, Etest and M.I.C.E. methodologies. The MIC values were interpreted according to CLSI susceptibility breakpoints and compared by regression analysis. RESULTS: In general, the essential agreement (±1-log2 between M.I.C.E. and CLSI agar dilution was 93.0%, 84.0% and 77.0% for linezolid, teicoplanin and vancomycin, respectively. Essential agreement rates between M.I.C.E. and Etest were excellent (>90.0% for all antibiotics tested. Both strips (M.I.C.E. and Etest yielded two very major errors for linezolid. Unacceptable minor rates were observed for teicoplanin against CoNS and for vancomycin against S. aureus. CONCLUSIONS: According to our results, linezolid and teicoplanin MICs against all staphylococci and S. aureus, respectively, were more accurately predicted by M.I.C.E. strips. However, the Etest showed better performance than M.I.C.E. for predicting vancomycin MICs against all staphylococci. Thus, microbiologists must be aware of the different performance of commercially available gradient strips against staphylococci.

Bile Culture and Susceptibility Testing of Malignant Biliary Obstruction via PTBD

Energy Technology Data Exchange (ETDEWEB)

Yu Haipeng; Guo Zhi, E-mail: jieruke@yahoo.com.cn; Xing Wenge; Guo Xiuying; Liu Fang; Li Baoguo [Tinajin Medical University Cancer Institute and Hospital, Department of Interventional Therapy, Tianjin Key Cancer Prevention and Treatment Laboratory (China)

2012-10-15

Purpose: To assess the information obtained by bile culture and susceptibility testing for malignant biliary obstruction by a retrospective one-center study. Methods: A total of 694 patients with malignant biliary obstruction received percutaneous transhepatic biliary drainage during the period July 2003 to September 2010, and subsequently, bile specimens were collected during the procedure. Among the 694 patients, 485 were men and 209 were women, ranging in age from 38 to 78 years (mean age 62 years). Results: A total of 42.9% patients had a positive bile culture (298 of 694). Further, 57 species of microorganisms and 342 strains were identified; gram-positive bacteria accounted for 50.9% (174 of 342) and gram-negative bacteria accounted for 41.5% (142 of 342) of these strains. No anaerobes were obtained by culture during this study. The most common microorganisms were Enterococcus faecalis (41 of 342, 11.9%), Escherichia coli (34 of 342, 9.9%), Klebsiella pneumoniae (28 of 342, 8.2%), Staphylococcus epidermidis (19 of 342, 5.5%), Enterococcus (18 of 342, 5.3%), and Enterobacter cloacae (16 of 342, 4.7%). The percentage of {beta}-lactamase-producing gram-positive bacteria was 27.6% (48 of 174), and the percentage of gram-negative bacteria was 19.7% (28 of 142). The percentage of enzyme-producing Escherichia coli was 61.7% (21 of 34). Conclusion: The bile cultures in malignant biliary obstruction are different from those in the Tokyo Guidelines and other benign biliary obstruction researches, which indicates that a different antibacterial therapy should be applied. Thus, knowledge of the antimicrobial susceptibility data could aid in the better use of antibiotics for the empirical therapy of biliary infection combined with malignant biliary obstruction.

Bile Culture and Susceptibility Testing of Malignant Biliary Obstruction via PTBD

International Nuclear Information System (INIS)

Yu Haipeng; Guo Zhi; Xing Wenge; Guo Xiuying; Liu Fang; Li Baoguo

2012-01-01

Purpose: To assess the information obtained by bile culture and susceptibility testing for malignant biliary obstruction by a retrospective one-center study. Methods: A total of 694 patients with malignant biliary obstruction received percutaneous transhepatic biliary drainage during the period July 2003 to September 2010, and subsequently, bile specimens were collected during the procedure. Among the 694 patients, 485 were men and 209 were women, ranging in age from 38 to 78 years (mean age 62 years). Results: A total of 42.9% patients had a positive bile culture (298 of 694). Further, 57 species of microorganisms and 342 strains were identified; gram-positive bacteria accounted for 50.9% (174 of 342) and gram-negative bacteria accounted for 41.5% (142 of 342) of these strains. No anaerobes were obtained by culture during this study. The most common microorganisms were Enterococcus faecalis (41 of 342, 11.9%), Escherichia coli (34 of 342, 9.9%), Klebsiella pneumoniae (28 of 342, 8.2%), Staphylococcus epidermidis (19 of 342, 5.5%), Enterococcus (18 of 342, 5.3%), and Enterobacter cloacae (16 of 342, 4.7%). The percentage of β-lactamase-producing gram-positive bacteria was 27.6% (48 of 174), and the percentage of gram-negative bacteria was 19.7% (28 of 142). The percentage of enzyme-producing Escherichia coli was 61.7% (21 of 34). Conclusion: The bile cultures in malignant biliary obstruction are different from those in the Tokyo Guidelines and other benign biliary obstruction researches, which indicates that a different antibacterial therapy should be applied. Thus, knowledge of the antimicrobial susceptibility data could aid in the better use of antibiotics for the empirical therapy of biliary infection combined with malignant biliary obstruction.

Cracking susceptibility of stainless steel subjected to plasma disruption

International Nuclear Information System (INIS)

Madarame, H.

1995-01-01

The similarities and differences in the cracking susceptibility between welding and resolidification after plasma disruption were examined experimentally using a number of primary candidate alloy samples with different chemical compositions. The product of the number density and the average depth of the cracks was measured after simulated disruption, employing a hydrogen ion beam as the heat source, and was compared with the Varestraint test result. An adequate correlation was observed between them, which indicates that the cracking susceptibility during plasma disruption can be well estimated from the welding cracking susceptibility. (orig.)

Highly sensitive bacterial susceptibility test against penicillin using parylene-matrix chip.

Science.gov (United States)

Park, Jong-Min; Kim, Jo-Il; Song, Hyun-Woo; Noh, Joo-Yoon; Kang, Min-Jung; Pyun, Jae-Chul

2015-09-15

This work presented a highly sensitive bacterial antibiotic susceptibility test through β-lactamase assay using Parylene-matrix chip. β-lactamases (EC 3.5.2.6) are an important family of enzymes that confer resistance to β-lactam antibiotics by catalyzing the hydrolysis of these antibiotics. Here we present a highly sensitive assay to quantitate β-lactamase-mediated hydrolysis of penicillin into penicilloic acid. Typically, MALDI-TOF mass spectrometry has been used to quantitate low molecular weight analytes and to discriminate them from noise peaks of matrix fragments that occur at low m/z ratios (m/ztest was carried out using Parylene-matrix chip and MALDI-TOF mass spectrometry. The Parylene-matrix chip was successfully used to quantitate penicillin (m/z: [PEN+H](+)=335.1 and [PEN+Na](+)=357.8) and penicilloic acid (m/z: [PA+H](+)=353.1) in a β-lactamase assay with minimal interference of low molecular weight noise peaks. The β-lactamase assay was carried out with an antibiotic-resistant E. coli strain and an antibiotic-susceptible E. coli strain, revealing that the minimum number of E. coli cells required to screen for antibiotic resistance was 1000 cells for the MALDI-TOF mass spectrometry/Parylene-matrix chip assay. Copyright © 2015 Elsevier B.V. All rights reserved.

antimicrobial susceptibility pattern of urinary pathogens isolated ...

African Journals Online (AJOL)

boaz

Conclusion: This study justifies the necessity to treat patients with UTI based on antimicrobial susceptibility test result in order ... colonization of the urine and symptomatic infection ... indicated a high incidence of UTIs (54%) in pregnant women ...

Comparison of E.test and Disk Diffusion Agar in Detection of Antibiotic Susceptibility of E.coli Isolated from Patients with Urinary Tract Infection in Tehran Shariati Hospital

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Y. Erfani

2008-07-01

Full Text Available Introduction & Objective: UTI is one of the most common bacterial infections and Ecoli is known as an important cause of UTIs. Since bacterial resistances of antibiotics are increasing, reliable methods of antimicrobial resistance detection are of paramount importance in treatment and management of UTIs. The objective of the present study is to compare and to evaluate the performance of disk diffusion agar (Iranian and Italian and E.test (Epsilometer test (Sweden for antimicrobial susceptibility testing of Ecoli isolated from UTI.Materials & Methods: This study was done on 250 Isolates of Ecoli from patients with UTI in Shariati Hospital, Tehran University of Medical Sciences during 2004. Antibiotic susceptibility testing was performed by disk diffusion method using Iranian and Italian disk for Trimetoprim sulfamethoxazole, Gentamysin, Ceftazidim, Nitrofurantoin and Ciprofluxacin and Minimum Inhibitory concentration (MIC determination was performed by E.test for the same set of antimicrobial. All tests were performed on muller hinton agar. Results: Comparison of E.test and Iranian disk diffusion agar showed that paramount differences in antibiotic agreement (Max 37.8 % those differences in case of Ceftazidim and Gentamysin were respectively 76.8% and 62.2% whereas comparison of E.test and Italian disk diffusion agar showed less difference of antibiotics agreement (Max 11.2%.Conclusion: The results of this study showed that Iranian disk diffusion agar may be used as a preliminary screen for antibiotic susceptibility testing of E.coli and is less sensitive than Italian disk diffusion and E.test. Comparison of 3 mentioned methods have showed that E.test is the most sensitive and shows the effective dose of antibiotic for treatment and prevention of antibiotic resistance.

ESBL Detection: Comparison of a Commercially Available Chromogenic Test for Third Generation Cephalosporine Resistance and Automated Susceptibility Testing in Enterobactericeae.

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Mohamed Ramadan El-Jade

Full Text Available Rapid detection and reporting of third generation cephalosporine resistance (3GC-R and of extended spectrum betalactamases in Enterobacteriaceae (ESBL-E is a diagnostic and therapeutic priority to avoid inefficacy of the initial antibiotic regimen. In this study we evaluated a commercially available chromogenic screen for 3GC-R as a predictive and/or confirmatory test for ESBL and AmpC activity in clinical and veterinary Enterobacteriaceae isolates. The test was highly reliable in the prediction of cefotaxime and cefpodoxime resistance, but there was no correlation with ceftazidime and piperacillin/tazobactam minimal inhibitory concentrations. All human and porcine ESBL-E tested were detected with exception of one genetically positive but phenotypically negative isolate. By contrast, AmpC detection rates lay below 30%. Notably, exclusion of piperacillin/tazobactam resistant, 3GC susceptible K1+ Klebsiella isolates increased the sensitivity and specificity of the test for ESBL detection. Our data further imply that in regions with low prevalence of AmpC and K1 positive E. coli strains chromogenic testing for 3GC-R can substitute for more time consuming ESBL confirmative testing in E. coli isolates tested positive by Phoenix or VITEK2 ESBL screen. We, therefore, suggest a diagnostic algorithm that distinguishes 3GC-R screening from primary culture and species-dependent confirmatory ESBL testing by βLACTATM and discuss the implications of MIC distribution results on the choice of antibiotic regimen.

Susceptibility to hypoxia and breathing control changes after short-term cold exposures

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Lyudmila T. Kovtun

2013-08-01

Full Text Available Background . Hypoxia is the reduction of oxygen availability due to external or internal causes. There is large individual variability of response to hypoxia. Objective . The aim of this study was to define individual and typological features in susceptibility to hypoxia, its interrelation with hypoxic and hypercapnic ventilatory responses (HVR and HCVR, respectively and their changes after cold acclimation. Design . Twenty-four healthy men were tested. HVR and HCVR were measured by the rebreathing method during hypoxic and hypercapnic tests, respectively. These tests were carried out in thermoneutral conditions before and after cold exposures (nude, at 13°C, 2 h daily, for 10 days. Susceptibility to hypoxia (sSaO2 was determined as haemoglobin saturation slope during hypoxic test. Results . It was found that HVR and HCVR significantly increased and susceptibility to hypoxia (sSaO2 tended to decrease after cold acclimation. According to sSaO2 results before cold exposures, the group was divided into 3: Group 1 – with high susceptibility to hypoxia, Group 2 – medium and Group 3 – low susceptibility. Analysis of variances (MANOVA shows the key role of susceptibility to hypoxia and cold exposures and their interrelation. Posterior analysis (Fisher LSD showed significant difference in susceptibility to hypoxia between the groups prior to cold acclimation, while HVR and HCVR did not differ between the groups. After cold acclimation, susceptibility to hypoxia was not significantly different between the groups, while HCVR significantly increased in Groups 1 and 3, HVR significantly increased in Group 3 and HCVR, HVR did not change in Group 2. Conclusions . Short-term cold exposures caused an increase in functional reserves and improved oxygen supply of tissues in Group 1. Cold exposure hypoxia has caused energy loss in Group 3. Group 2 showed the most appropriate energy conservation reaction mode to cold exposures. No relation was found between

Responses of Nasonovia ribisnigri (Homoptera: Aphididae) to susceptible and resistant lettuce.

Science.gov (United States)

Liu, Yong-Biao; McCreight, James D

2006-06-01

Nymphs and alates of aphid Nasonovia ribisnigri (Mosley) (Homoptera: Aphididae) were tested on 10 lettuce cultivars with N. ribisnigri resistance gene Nr and 18 cultivars without the resistance gene in various bioassays. Bioassays used whole plants, leaf discs, or leaf cages to determine susceptibility of commercial lettuce cultivars to N. ribisnigri infestation and to evaluate screening methods for breeding lettuce resistance to N. ribisnigri. Resistant and susceptible plants were separated in 3 d when using whole plant bioassays. Long-term (> or =7 d) no-choice tests using leaf cages or whole plants resulted in no survival of N. ribisnigri on resistant plants, indicating great promise of the Nr gene for management of N. ribisnigri. Effective screening was achieved in both no-choice tests where resistant or susceptible intact plants were tested separately in groups or individually and in choice tests where susceptible and resistant plants were intermixed. Leaf discs bioassays were not suitable for resistance screening. All lettuce cultivars without the resistance gene were suitable hosts for N. ribisnigri, indicating the great importance of this pest to lettuce production and the urgency in developing resistant lettuce cultivars to manage N. ribisnigri.

Genotyping and antifungal susceptibility testing of multiple Malassezia pachydermatis isolates from otitis and dermatitis cases in pets: is it really worth the effort?

Science.gov (United States)

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

2016-01-01

A total of 216 colonies of Malassezia pachydermatis from 28 cases of fungal otitis or dermatitis in pets were genotyped by M13 fingerprinting and tested for antifungal susceptibility. A huge genetic diversity was found (157 M13 types in total), with all animals having a polyclonal pattern of infection (5.4 ± 1.5 genotypes/sample). Furthermore, analysis of molecular variance (AMOVA) revealed that most genetic diversity (44%) was found at the within sample level. In contrast, variability in antifungal susceptibility among isolates from the same sample was less important, with different M13 types displaying in most cases identical or very similar MIC results. Most isolates displayed high in vitro susceptibility to amphotericin B, terbinafine and all azoles tested except fluconazole, for which MIC values were always ≥4 μg/ml and a 26.9% of isolates displayed values ≥32 μg/ml. We conclude that although characterization of multiple yeast isolates results in a considerable increase in laboratory workload and expenses, it may help to get a better understanding of the epidemiology of M. pachydermatis in a given patient population. © The Author 2015. 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.

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

Science.gov (United States)

LeBoldus, Jared M; Isabel, Nathalie; Floate, Kevin D; Blenis, Peter; Thomas, Barb R

2013-01-01

Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis) and (or) to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or) hybridization ('phenological sink' hypothesis). We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined]) zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal pathogens in plant

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

Directory of Open Access Journals (Sweden)

Jared M LeBoldus

Full Text Available Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis and (or to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or hybridization ('phenological sink' hypothesis. We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined] zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal

Reversion of High-level Mecillinam Resistance to Susceptibility in Escherichia coli During Growth in Urine

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Elisabeth Thulin

2017-09-01

This is the first example describing conditional resistance where a genetically stable antibiotic resistance can be phenotypically reverted to susceptibility by metabolites present in urine. These findings have several important clinical implications regarding the use of mecillinam to treat UTIs. First, they suggest that mecillinam can be used to treat also those clinical strains that are identified as MecR in standard laboratory tests. Second, the results suggest that testing of mecillinam susceptibility in the laboratory ought to be performed in media that mimics urine to obtain clinically relevant susceptibility testing results. Third, these findings imply that changes in patient behavior, such as increased water intake or use of diuretics to reduce urine osmolality and increased intake of cysteine, might induce antibiotic susceptibility in an infecting MecR E. coli strain and thereby increase treatment efficiency.

Drug susceptibility testing of Mycobacterium Avium subsp. Avium isolates from naturally infected domestic pigeons to avian tuberculosis

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Kaveh Parvandar

2016-01-01

Conclusion: We suggest drug susceptibility testing for more nontuberculous mycobateria, particularly M. avium complex isolated from infected birds and humans, as well as molecular basics of drug sensitivity in order to detect resistance genes of pathogenic M. avium subsp. avium.

A prospective study of the impact of genetic susceptibility testing for BRCA1/2 or HNPCC on family relationships

NARCIS (Netherlands)

van Oostrom, Iris; Meijers-Heijboer, Hanne; Duivenvoorden, Hugo J.; Brocker-Vriends, Annette H. J. T.; van Asperen, Chhstl J.; Sijmons, Rolf H.; Seynaeve, Caroline; Van Gool, Arthur R.; Klijn, Jan G. M.; Riedijk, Samantha R.; van Dooren, Silvia; Tibben, Aad

This study assessed the impact of genetic testing for cancer susceptibility on family relationships and determinants of adverse consequences for family relationships. Applicants for genetic testing of a known familial pathogenic mutation in BRCA1/2 or a HNPCC related gene (N = 271) rated the

A prospective study of the impact of genetic susceptibility testing for BRCA1/2 or HNPCC on family relationships

NARCIS (Netherlands)

van Oostrom, Iris; Meijers-Heijboer, Hanne; Duivenvoorden, Hugo J.; Bröcker-Vriends, Annette H. J. T.; van Asperen, Christi J.; Sijmons, Rolf H.; Seynaeve, Caroline; van Gool, Arthur R.; Klijn, Jan G. M.; Riedijk, Samantha R.; van Dooren, Silvia; Tibben, Aad

2007-01-01

This study assessed the impact of genetic testing for cancer susceptibility on family relationships and determinants of adverse consequences for family relationships. Applicants for genetic testing of a known familial pathogenic mutation in BRCA1/2 or a HNPCC related gene (N=271) rated the

A prospective study of the impact of genetic susceptibility testing for BRCA1/2 or HNPCC on family relationships.

NARCIS (Netherlands)

Oostrom, I.I.H. van; Meijers-Heijboer, H.; Duivenvoorden, H.J.; Brocker-Vriends, A.H.; Asperen, C.J. van; Sijmons, R.H.; Seynaeve, C.; Gool, A.R. van; Klijn, J.G.M.; Riedijk, S.R.; Dooren, S. van; Tibben, A.

2007-01-01

This study assessed the impact of genetic testing for cancer susceptibility on family relationships and determinants of adverse consequences for family relationships. Applicants for genetic testing of a known familial pathogenic mutation in BRCA1/2 or a HNPCC related gene (N=271) rated the

Antimicrobial susceptibility patterns of Brazilian Haemophilus parasuis field isolates

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Michela Miani

Full Text Available ABSTRACT: Haemophilus parasuis is the etiological agent of Glässer’s disease (GD, an ubiquitous infection of swine characterized by systemic fibrinous polyserositis, polyarthritis and meningitis. Intensive use of antimicrobial agents in swine husbandries during the last years triggered the development of antibiotic resistances in bacterial pathogens. Thus, regular susceptibility testing is crucial to ensure efficacy of different antimicrobial agents to this porcine pathogen. In this study, 50 clinical isolates from South Brazilian pig herds were characterized and analyzed for their susceptibility to commonly used antibiotic. The identification and typing of clinical isolates was carried out by a modified indirect hemagglutination assay combined with a multiplex PCR. The susceptibility of each isolate was analyzed by broth microdilution method against a panel of 21 antimicrobial compounds. We found that field isolates are highly resistance to gentamycin, bacitracin, lincomycin and tiamulin, but sensitive to ampicillin, clindamycin, neomycin, penicillin, danofloxacin and enrofloxacin. Furthermore, an individual susceptibility analysis indicated that enrofloxacin is effective to treat clinical isolates with the exception of those classified as serovar 1. The results presented here firstly demonstrate the susceptibility of Brazilian clinical isolates of H. parasuis to antimicrobials widely used by swine veterinary practitioners and strengthen the need to perform susceptibility test prior to antibiotic therapy during GD outbreaks. In addition, because only six antimicrobial drugs (28.6% were found effective against field isolates, a continuous surveillance of the susceptibility profile should be of major concern to the swine industry.

Culture and drug susceptibility testing among previously treated tuberculosis patients in the Dominican Republic, 2014

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Katia J. Romero Mercado

Full Text Available ABSTRACT Multidrug-resistant tuberculosis (MDR-TB is a major public health concern that threatens global progress toward effective TB control. The risk of MDR-TB is increased in patients who have received previous TB treatment. This article describes the performance of culture and drug susceptibility testing (DST in patients registered as previously treated TB patients in the Dominican Republic in 2014, based on operational research that followed a retrospective cohort design and used routine program data. Under the current system of TB culturing and DST, the majority of patients with previously treated TB do not undergo DST, and those who do often experience considerable delay in obtaining their results. The lack of DST and delay in receiving DST results leads to underestimation of the number of MDR-TB cases and hinders the timely initiation of MDR-TB treatment.

Pre-Use Susceptibility to Ceftaroline in Clinical Staphylococcus aureus Isolates from Germany: Is There a Non-Susceptible Pool to be Selected?

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Birgit Strommenger

Full Text Available Ceftaroline is a new cephalosporin active against Methicillin-resistant Staphylococcus aureus (MRSA. Based on a representative collection of clinical S. aureus isolates from Germany, supplemented with isolates of clonal lineages ST228 and ST239, we demonstrate the in-vitro susceptibility towards ceftaroline prior to its introduction into clinical use for a total of 219 isolates. Susceptibility testing was performed by broth microdilution, disc diffusion and Etest, respectively. Results were interpreted according to EUCAST guidelines and showed considerable variance in dependence on clonal affiliation of the isolates tested. Among isolates of widespread hospital-associated lineages we found a high proportion of clinical isolates with MICs close to the EUCAST breakpoint (MIC50/90 1.0/1.5 mg/L; currently, interpretation of these "borderline" MICs is complicated by a lack of concordant susceptibility testing methods and reasonable breakpoint determination. Isolates of clonal lineages ST228 and ST239 demonstrated increased MIC50/90 values of 2.5/3.33 mg/L. Sequencing of mecA revealed no association of resistance to a specific mecA polymorphism, but rather reveals two regions in the non-penicillin-binding domain of PbP2a which displayed different combinations of mutations putatively involved in resistance development. This study provides national baseline data to (i adjust susceptibility testing methods and current breakpoints to clinical and epidemiological requirements, (ii evaluate current breakpoints with respect to therapeutic outcome and (iii monitor further resistance evolution.

Comparison of Two Different Disk Diffusion Agar Tests in Determination of Antibiotic Susceptibility for E-Coli Isolated from Urinary Tract Infection in Pediatrics

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I. Sedighi

2010-04-01

Full Text Available Introduction & Objective: Urinary Tract Infection (UTI is one of the most common infections during childhood and E-Coli is the more predominant pathogen recovered in UTI. Disk Diffusion agar test is a method of choice because it is cost effective, simple, and now routinely used for detection of antibiotic susceptibility. A rapid increase in antibiotic resistance in our region made the authors to design a study to compare this traditional method with two different disk diffusion agar tests.Materials & Methods: Our study was conducted between 2009 and 2010 in Be’sat teaching hospital on 100 pediatric patients ranged 15 days to 13 years old with positive urine culture for E-coli. Antibiogram detection was performed by disk diffusion agar test with two different kits as Padtan-Teb (made in Iran and Mast (made in the U.K. for Co-trimoxazol, Amikacin, Ceftriaxone, Nalidixic Acid, Cefixime, and Nitrofurantoin. At last the data was analyzed by McNemar test.Results: Co-trimoxazol obtained the lowest (23% Padtan-Teb and 26% Mast and Nitrofurantoin had the highest (86% Padtan-Teb and 97% Mast sensitivity in the two methods which were used in our study. The results were statistically significant for Amikacin, Ceftriaxone, Cefixime, and Nitrofurantoin. The data was analyzed by Mc Memar test.Conclusion: According to our study the results of antibiotic susceptibility were more compatible with other non national Disk diffusion agar test and thus we recommend that our manufactures in Iran should increase the quality of their products.

[First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans/ Anaerobic Subcommittee of the Asociación Argentina de Microbiología].

Science.gov (United States)

Legaria, María C; Bianchini, Hebe M; Castello, Liliana; Carloni, Graciela; Di Martino, Ana; Fernández Canigia, Liliana; Litterio, Mirta; Rollet, Raquel; Rossetti, Adelaida; Predari, Silvia C

2011-01-01

Through time, anaerobic bacteria have shown good susceptibility to clinically useful antianaerobic agents. Nevertheless, the antimicrobial resistance profile of most of the anaerobic species related to severe infections in humans has been modified in the last years and different kinds of resistance to the most active agents have emerged, making their effectiveness less predictable. With the aim of finding an answer and for the purpose of facilitating the detection of anaerobic antimicrobial resistance, the Anaerobic Subcommittee of the Asociación Argentina de Microbiología developed the First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans. This document resulted from the compatibilization of the Clinical and Laboratory Standards Institute recommendations, the international literature and the work and experience of the Subcommittee. The Consensus document provides a brief taxonomy review, and exposes why and when anaerobic antimicrobial susceptibility tests should be conducted, and which antimicrobial agents can be used according to the species involved. The recommendations on how to perform, read and interpret in vitro anaerobic antimicrobial susceptibility tests with each method are exposed. Finally, the antibiotic susceptibility profile, the classification of antibiotics according to their in vitro activities, the natural and acquired mechanisms of resistance, the emerging resistance and the regional antibiotic resistance profile of clinically relevant anaerobic species are shown.

Evaluation of SCC susceptibility of alloy 800 under CANDU SG secondary-side conditions

International Nuclear Information System (INIS)

Liu, S.; Lu, Y.

2006-01-01

As part of a coordinated program, AECL is developing a set of tools to aid with the prediction and management of steam generator performance. Although stress corrosion cracking (of Alloy 800) has not been detected in any operating steam generator, for life management it is necessary to develop mechanistic models to predict the conditions under which stress corrosion cracking is plausible. Therefore, constant extension rate tests were carried out for Alloy 800 under various steam generator crevice chemistry conditions at applied potentials. These tests were designed to evaluate the stress corrosion cracking susceptibility of Alloy 800 under CANDU( steam generator operating conditions. Based on the experimental results, the recommended electrochemical corrosion potential/pH zone for Alloy 800 determined by electrochemical polarization measurements was verified with the respect of stress corrosion cracking susceptibility. The effects of lead contamination on the stress corrosion cracking susceptibility of Alloy 800 tubing were also evaluated. The experimental results from constant extension rate tests obtained under applied potentials suggest that Alloy 800 has good performance inside much of a previously recommended electrochemical corrosion potential/pH zone determined by electrochemical analysis. Alloy 800 is not susceptible to stress corrosion cracking under normal CANDU steam generator operating conditions. However, Alloy 800 may be susceptible to stress corrosion cracking under near-neutral crevice chemistry conditions in the presence of oxidants. In addition, stress corrosion cracking susceptibility is increased by lead contamination. This observation suggests that the previously defined electrochemical corrosion potential limit under near-neutral crevice conditions could be modified to minimize stress corrosion cracking of Alloy 800. The test results from this work also suggest that the pH dependency of the stress corrosion cracking susceptibility of Alloy 800

Lyophilized microculture susceptibility test for ketoconazole, miconazole, clotrimazole, and griseofulvin against dermatophytes.

Science.gov (United States)

Granade, T C; Mothershead, M A; Artis, W M

1983-07-01

A lyophilized microculture antimycotic susceptibility testing system for ketoconazole, miconazole, griseofulvin, and clotrimazole is described. Microculture plates were loaded with 100 microliters of medium and 10 microliters of appropriate concentrations of the four antimycotics and were lyophilized to complete dryness. The lyophilized plates were stored at -70 degrees C or 4 degrees C or in a desiccator at 25 degrees C. Samples from each storage condition were rehydrated at 1, 2, 3, 4, 5, 6, 8, 10, and 12 months and inoculated with Trichophyton mentagrophytes (Robin) Blanchard ATCC 18748. All of the minimal inhibitory concentrations (MICs) generated from the lyophilized microcultures were within one experimental dilution of MICs derived from fresh microcultures. The ability of reconstituted lyophilized microcultures to consistently produce MICs comparable to MICs derived from fresh microcultures was characterized. Nine dermatophyte isolates were tested five times each over a 70-day period. The MICs derived were reproducible and comparable to MICs determined by freshly prepared microculture tests. Lyophilization of freshly prepared antimycotic-containing microcultures does not alter the MIC resolution of the testing system and provides an effective method of storage of prepared antimycotic tests for ketoconazole, miconazole, clotrimazole, and griseofulvin.

Antimicrobial susceptibility of Brachyspira hyodysenteriae isolated from 21 Polish farms.

Science.gov (United States)

Zmudzki, J; Szczotka, A; Nowak, A; Strzelecka, H; Grzesiak, A; Pejsak, Z

2012-01-01

Swine dysentery (SD) is a common disease among pigs worldwide, which contributes to major production losses. Antimicrobial susceptibility testing of B. hyodysenteriae, the etiological agent of SD, is mainly performed by the agar dilution method. This method has certain limitations due to difficulties in interpretation of results. The aim of this study was the analysis of antimicrobial susceptibility of Brachyspira hyodysenteriae (B. hyodysenteriae) Polish field isolates by broth microdilution procedure. The study was performed on 21 isolates of B. hyodysenteriae, collected between January 2006 to December 2010 from cases of swine dysentery. VetMIC Brachyspira panels with antimicrobial agents (tiamulin, valnemulin, doxycycline, lincomycin, tylosin and ampicillin) were used for susceptibility testing of B. hyodysenteriae. The minimal inhibitory concentration (MIC) was determined by the broth dilution procedure. The lowest antimicrobial activity was demonstrated for tylosin and lincomycin, with inhibition of bacterial growth using concentrations > 128 microg/ml and 32 microg/ml, respectively. In the case of doxycycline, the MIC values were < or = 2.0 microg/ml. No decreased susceptibility to tiamulin was found among the Polish isolates and MIC values for this antibiotic did not exceed 1.0 microg/ml. The results of the present study confirmed that Polish B. hyodysenteriae isolates were susceptible to the main antibiotics (tiamulin and valnemulin) used in treatment of swine dysentery. Further studies are necessary to evaluate a possible slow decrease in susceptibility to tiamulin and valnemulin of B. hyodysenteriae strains in Poland.

In vitro susceptibilities of Brucella melitensis isolates to eleven antibiotics

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Loukaides Feidias

2006-10-01

Full Text Available Abstract Background Brucellosis is an endemic disease present in many countries worldwide, but it is rare in Europe and North America. Nevertheless brucella is included in the bacteria potentially used for bioterrorism. The aim of this study was the investigation of the antibiotic susceptibility profile of brucella isolates from areas of the eastern Mediterranean where it has been endemic. Methods The susceptibilities of 74 Brucella melitensis isolates derived from clinical samples (57 and animal products (17 were tested in vitro. The strains originate from Crete (59, Cyprus (10, and Syria (5. MICs of tetracycline, rifampicin, streptomycin, gentamicin, norfloxacin, ciprofloxacin, levofloxacin, trimethoprim/sulfamethoxazole, ampicillin, amoxicillin/clavulanic acid, and erythromycin were detected by E-test method. The NCCLS criteria for slow growing bacteria were considered to interpret the results. Results All the isolates were susceptible to tetracycline, streptomycin, gentamicin, ciprofloxacin, norfloxacin, and levofloxacin. Two isolates presented reduced susceptibility to rifampicin (MIC value: 1.5 mg/l and eight to SXT (MIC values: 0.75–1.5 mg/l. Erythromycin had the highest (4 mg/l MIC90value and both norfloxacin and erythromycin the highest (1.5 mg/l MIC50 value. Conclusion Brucella isolates remain susceptible in vitro to most antibiotics used for treatment of brucellosis. The establishment of a standardized antibiotic susceptibility method for Brucella spp would be useful for resistance determination in these bacteria and possible evaluation of bioterorism risks.

Antimicrobial resistance in methicillin susceptible and methicillin resistant Staphylococcus pseudintermedius of canine origin

DEFF Research Database (Denmark)

Moodley, Arshnee; Damborg, Peter Panduro; Nielsen, Søren Saxmose

2014-01-01

and enrofloxacin amongst MSSP. The review highlights inconsistencies between studies as a result of several factors, for example the use of different antimicrobial susceptibility testing methods and interpretation criteria. We recommend that data on susceptibility in important companion animal pathogens...

Culture and Next-generation sequencing-based drug susceptibility testing unveil high levels of drug-resistant-TB in Djibouti: results from the first national survey.

Science.gov (United States)

Tagliani, Elisa; Hassan, Mohamed Osman; Waberi, Yacine; De Filippo, Maria Rosaria; Falzon, Dennis; Dean, Anna; Zignol, Matteo; Supply, Philip; Abdoulkader, Mohamed Ali; Hassangue, Hawa; Cirillo, Daniela Maria

2017-12-15

Djibouti is a small country in the Horn of Africa with a high TB incidence (378/100,000 in 2015). Multidrug-resistant TB (MDR-TB) and resistance to second-line agents have been previously identified in the country but the extent of the problem has yet to be quantified. A national survey was conducted to estimate the proportion of MDR-TB among a representative sample of TB patients. Sputum was tested using XpertMTB/RIF and samples positive for MTB and resistant to rifampicin underwent first line phenotypic susceptibility testing. The TB supranational reference laboratory in Milan, Italy, undertook external quality assurance, genotypic testing based on whole genome and targeted-deep sequencing and phylogenetic studies. 301 new and 66 previously treated TB cases were enrolled. MDR-TB was detected in 34 patients: 4.7% of new and 31% of previously treated cases. Resistance to pyrazinamide, aminoglycosides and capreomycin was detected in 68%, 18% and 29% of MDR-TB strains respectively, while resistance to fluoroquinolones was not detected. Cluster analysis identified transmission of MDR-TB as a critical factor fostering drug resistance in the country. Levels of MDR-TB in Djibouti are among the highest on the African continent. High prevalence of resistance to pyrazinamide and second-line injectable agents have important implications for treatment regimens.

Prognostic factors for hereditary cancer distress six months after BRCA1/2 or HNPCC genetic susceptibility testing

NARCIS (Netherlands)

van Oostrom, Iris; Meijers-Heijboer, Hanne; Duivenvoorden, Hugo J.; Brocker-Vriends, Annette H. J. T.; van Asperen, Christi J.; Sijmons, Rolf H.; Seynaeve, Caroline; Van Gool, Arthur R.; Klijn, Jan G. M.; Tibben, Aad

This study explored predictors for hereditary cancer distress six months after genetic susceptibility testing for a known familial BRCA1/2 or HNPCC related mutation, in order to gain insight into aspects relevant for the identification of individuals needing additional psychosocial support. Coping,

Analysis of the magnetic susceptibility well log in drill hole UE25a-5, Yucca Mountain, Nevada Test Site

International Nuclear Information System (INIS)

Hagstrum, J.T.; Daniels, J.J.; Scott, J.H.

1980-01-01

Magnetic susceptibility measurements have been shown to be dependent upon the magnetite content of rocks with variations in rock susceptibility arising from changes in the shape, size, composition, and quantity of the contained magnetite grains. The present study was undertaken to determine the factor(s) responsible for the variation in magnetic susceptibility measurements from borehole UE25a-5 on the Nevada Test Site (NTS). The well logs and sample analyses presented in this paper form part of a larger geophysical well-logging project studying the physical properties of welded tuffs at NTS. The ash-flow sheets at NTS appear to be the products of single compositionally zoned magmas that tend, within a cooling unit, to erupt hotter, more mafic, and more crystal-rich with time. These factors, however, have little effect on the degree to which the tuffs become welded. Furthermore, zones of crystallization and alteration are superimposed upon the welded units. X-ray data show poor correspondence between the relative abundance of magnetite in a sample and the borehole magnetic susceptibility measurement associated with it. Curie balance experiments demonstrate no change in the magnetic mineralogy that could account for the susceptibility variation. Thin-section observations corroborate the x-ray data, but indicate a proportional relationship between the borehole susceptibility measurements and the grain-size distribution of magnetite. The association of magnetic susceptibility anomalies with the crystal-rich zones of the welded tuffs will aid in the identification and correlation of the eruptive sequences at NTS

Antimicrobial susceptibility of clinical isolates of anaerobic bacteria in Ontario, 2010-2011.

Science.gov (United States)

Marchand-Austin, Alex; Rawte, Prasad; Toye, Baldwin; Jamieson, Frances B; Farrell, David J; Patel, Samir N

2014-08-01

The local epidemiology of antimicrobial susceptibility patterns in anaerobic bacteria is important in guiding the empiric treatment of infections. However, susceptibility data are very limited on anaerobic organisms, particularly among non-Bacteroides organisms. To determine susceptibility profiles of clinically-significant anaerobic bacteria in Ontario Canada, anaerobic isolates from sterile sites submitted to Public Health Ontario Laboratory (PHOL) for identification and susceptibility testing were included in this study. Using the E-test method, isolates were tested for various antimicrobials including, penicillin, cefoxitin, clindamycin, meropenem, piperacillin-tazobactam and metronidazole. The MIC results were interpreted based on guidelines published by Clinical and Laboratory Standards Institute. Of 2527 anaerobic isolates submitted to PHOL, 1412 were either from sterile sites or bronchial lavage, and underwent susceptibility testing. Among Bacteroides fragilis, 98.2%, 24.7%, 1.6%, and 1.2% were resistant to penicillin, clindamycin, piperacillin-tazobactam, and metronidazole, respectively. Clostridium perfringens was universally susceptible to penicillin, piperacillin-tazobactam, and meropenem, whereas 14.2% of other Clostridium spp. were resistant to penicillin. Among Gram-positive anaerobes, Actinomyces spp., Parvimonas micra and Propionibacterium spp. were universally susceptible to β-lactams. Eggerthella spp., Collinsella spp., and Eubacterium spp. showed variable resistance to penicillin. Among Gram-negative anaerobes, Fusobacterium spp., Prevotella spp., and Veillonella spp. showed high resistance to penicillin but were universally susceptible to meropenem and piperacillin-tazobactam. The detection of metronidazole resistant B. fragilis is concerning as occurrence of these isolates is extremely rare. These data highlight the importance of ongoing surveillance to provide clinically relevant information to clinicians for empiric management of

Comparative drug susceptibility study of five clonal strains of Trichomonas vaginalis in vitro

Institute of Scientific and Technical Information of China (English)

Hemantkumar Somabhai Chaudhari; Prati Pal Singh

2011-01-01

Objective: To produce comparative data on a group of Trichomonas vaginalis clonal strains with varied drug responses using identical methods and materials. Methods: Five clonal strains of Trichomonas vaginalis were isolated from reference strain using agar plate technique. The variability of growth kinetic and susceptibility of clonal strain to metronidazole, tinidazole, satranidazole and nitazoxanide were observed in 96 well microtitre plate. Results: Among these clonal strains there was a good correlation between rates of growth with the relative susceptibility of the strains to drugs in vitro. Regarding metronidazole, tinidazole and satranidazole susceptibility, different degrees of susceptibility were determined. However, no difference in nitazoxanide susceptibility was found between the clonal strain tested and a reference strain.Conclusions: This is the first description of biological variability in clonal stock of Trichomonas vaginalis. Different degrees of drug susceptibility were determined among clonal strains tested. Further studies will be necessary to ascertain the importance of this variability in clinical infection.

Analysis of the X-ray microbeam test result of the flash memories

International Nuclear Information System (INIS)

Yan Yihua; Ding Lili; Chen Wei; Guo Hongxia; Guo Xiaoqiang; Lin Dongsheng; Zhang Keying; Zhang Fengqi; Deng Yuliang; Fan Ruyu

2013-01-01

Background: The failure phenomenon is difficult to analyze for the flash memories when the whole chip is exposed to irradiation since both the memory array and the peripheral circuits might be degraded. Purpose: In order to detect the radiation susceptibility and corresponding phenomenon of the related circuits that included in the flash memories, the X-ray microbeam is used as the radiation source instead of 60 Co. Methods: The failure phenomenon is studied respectively when the memory array, decoder circuits, the charge pump circuits as well as the I/O circuits are exposed to radiation. The errors are mapped according to the logical address and the failure mechanism is analyzed based on the circuits. Results: Irradiated on the memory .array win lead to regularly distributed 0→1 bit flips, while only 1→0 are found when the row decoder is under exposure. Degradation of the charge pump circuits would lead to the erase/program functional failure. Conclusions: The results suggest that the X-ray microbeam radiation test is a good method for detecting the radiation susceptibility of the integrated circuits that contains lots of circuit modules. (authors)

Ocular TRUST: nationwide antimicrobial susceptibility patterns in ocular isolates.

Science.gov (United States)

Asbell, Penny A; Colby, Kathryn A; Deng, Sophie; McDonnell, Peter; Meisler, David M; Raizman, Michael B; Sheppard, John D; Sahm, Daniel F

2008-06-01

Ocular Tracking Resistance in U.S. Today (TRUST) annually evaluates in vitro antimicrobial susceptibility of Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae to ciprofloxacin, gatifloxacin, levofloxacin, moxifloxacin, penicillin, azithromycin, tobramycin, trimethoprim, and polymyxin B in national samples of ocular isolates. Laboratory investigation. Prospectively collected ocular isolates (197 S. aureus, 49 S. pneumoniae, and 32 H. influenzae) from 35 institutions and archived ocular isolates (760 S. pneumoniae and 356 H. influenzae) from 34 institutions were tested by an independent, central laboratory. Mean minimum inhibitory concentrations that would inhibit growth of 90% of the tested isolates (MIC(90)) were interpreted as susceptible, intermediate, or resistant according to standardized breakpoints for systemic treatment. S. aureus isolates were classified as methicillin susceptible (MSSA) or methicillin resistant (MRSA). MSSA or MRSA susceptibility patterns were virtually identical for the fluoroquinolones, that is, MSSA susceptibility was 79.9% to 81.1% and MRSA susceptibility was 15.2%. Trimethoprim was the only agent tested with high activity against MRSA. All S. pneumoniae isolates were susceptible to gatifloxacin, levofloxacin, and moxifloxacin; 89.8% were susceptible to ciprofloxacin. H. influenzae isolates were 100% susceptible to all tested agents but trimethoprim. Ocular TRUST 1 data were consistent with the eight-year longitudinal sample of archived ocular isolates. The fluoroquinolones were consistently active in MSSA, S. pneumoniae, and H. influenzae. After more than a decade of intensive ciprofloxacin and levofloxacin use as systemic therapy, 100% of ocular S. pneumoniae isolates were susceptible to gatifloxacin, levofloxacin, and moxifloxacin; nonsusceptibility to ciprofloxacin was less than 15%. High-level in vitro MRSA resistance suggests the need to consider alternative therapy to fluoroquinolones when MRSA is a

Task 2 - Limits for High-Frequency Conducted Susceptibility Testing - CS114 (NRC-HQ-60-14-D-0015)

Energy Technology Data Exchange (ETDEWEB)

Wood, Richard Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ewing, Paul D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moses, Rebecca J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-09-01

A principal focus of Task 2 under this project was for ORNL to evaluate the basis for susceptibility testing against high-frequency conducted interference and to establish recommendations to resolve concerns about the severity of test limits for the conducted susceptibility (CS) test, CS114, from MIL-STD-461. The primary concern about the test limit has been characterized by the EPRI EMI Working Group in the following terms: Demonstrating compliance with the CS114 test limits recommended in TR-102323 has proven to be problematic, even for components that have been tested to commercial standards and demonstrated proper operation in industrial applications [6]. Specifically, EPRI notes that the CS114 limits approved in regulatory documents are significantly higher than those invoked by the US military and similar commercial standards in the frequency range below 200 kHz. For this task, ORNL evaluated the original approach to establishing the test limit, EPRI technical findings from a review of the limit, and the regulatory basis through which the currently approved limits were accepted. Based on this analysis, strategies have been developed regarding changes to the CS114 limit that can resolve the technical concerns raised by the industry. Guided by the principles that reasonable assurance of safety must not be compromised but excessive conservatism should be reduced, recommendations on a suitable basis for a revised limit have been developed and can be incorporated into the planned Revision 2 of RG 1.180.

Prevalence and Antimicrobial Susceptibility of Coagulase-Negative Staphylococci isolated from Bovine Mastitis

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Kaliwal B.B.

2011-08-01

Full Text Available The study was carried out to investigate the prevalence and antimicrobial susceptibility of Coagulase-Negative Staphylococci isolated from Bovine Mastitis in and around Dharwad region. A total of 310 samples were screened and 180 confirmed Coagulase-Negative Staphylococci were obtained. The antimicrobial susceptibility of Coagulase-Negative Staphylococci against 10 antimicrobial agents was tested using the disc diffusion method. The highest numbers of Coagulase-Negative Staphylococci were susceptible to ceftriaxone 83.88% followed by cefotaxime 79.41%, methicillin 76.47%, ciprofloxacin 73.52%, erythromycin 70.05%, amikacin 66.11%, gentamycin 42.94%, amoxicillin 36.76%, ampicillin 29.41%, and the lowest susceptibility was shown in penicillin 23.23% . The results indicated that the increase in prevalence and antibiotic resistance pattern of the Coagulase-Negative Staphylococci isolated from bovine mastitis exhibited the highest degree of susceptible to ceftriaxone of all the tested antimicrobial agents. [Vet. World 2011; 4(4.000: 158-161

Vancomycin-resistant Enterococcus spp.: validation of susceptibility testing and in vitro activity of vancomycin, linezolid, tigecycline and daptomycin

DEFF Research Database (Denmark)

Rathe, Mathias; Kristensen, Lise; Ellermann-Eriksen, Svend

2010-01-01

Vancomycin-resistant enterococci (VRE) have emerged to become a significant nosocomial pathogen. However, detection may be challenging and treatment possibilities are limited. Reports of resistance to linezolide, daptomycin and tigecycline underline the need for reliable susceptibility testing wi...

Antibiotic susceptibility of Atopobium vaginae

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Verschraegen Gerda

2006-03-01

Full Text Available Abstract Background Previous studies have indicated that a recently described anaerobic bacterium, Atopobium vaginae is associated with bacterial vaginosis (BV. Thus far the four isolates of this fastidious micro-organism were found to be highly resistant to metronidazole and susceptible for clindamycin, two antibiotics preferred for the treatment of BV. Methods Nine strains of Atopobium vaginae, four strains of Gardnerella vaginalis, two strains of Lactobacillus iners and one strain each of Bifidobacterium breve, B. longum, L. crispatus, L. gasseri and L. jensenii were tested against 15 antimicrobial agents using the Etest. Results All nine strains of A. vaginae were highly resistant to nalidixic acid and colistin while being inhibited by low concentrations of clindamycin (range: G. vaginalis strains were also susceptible for clindamycin ( 256 μg/ml but susceptible to clindamycin (0.023 – 0.125 μg/ml. Conclusion Clindamycin has higher activity against G. vaginalis and A. vaginae than metronidazole, but not all A. vaginae isolates are metronidazole resistant, as seemed to be a straightforward conclusion from previous studies on a more limited number of strains.

Antifungal susceptibility testing of Candida species isolated from the immunocompromised patients admitted to ten university hospitals in Iran : comparison of colonizing and infecting isolates

NARCIS (Netherlands)

Badiee, Parisa; Badali, Hamid; Boekhout, Teun; Diba, Kambiz; Moghadam, Abdolkarim Ghadimi; Hossaini Nasab, Ali; Jafarian, Hadis; Mohammadi, Rasoul; Mirhendi, Hossein; Najafzadeh, Mohammad Javad; Shamsizadeh, Ahmad; Soltani, Jafar

2017-01-01

BACKGROUND: Antifungal susceptibility testing is a subject of interest in the field of medical mycology. The aim of the present study were the distributions and antifungal susceptibility patterns of various Candida species isolated from colonized and infected immunocompromised patients admitted to

Susceptibility of Porphyromonas gingivalis in biofilms to amoxicillin, doxycycline and metronidazole

DEFF Research Database (Denmark)

Larsen, T.

2002-01-01

Biofilm, Porphyromonas gingivalis, susceptibility testing, amoxicillin, doxycycline, metronidazole......Biofilm, Porphyromonas gingivalis, susceptibility testing, amoxicillin, doxycycline, metronidazole...

qPCR-High resolution melt analysis for drug susceptibility testing of Mycobacterium leprae directly from clinical specimens of leprosy patients.

Science.gov (United States)

Araujo, Sergio; Goulart, Luiz Ricardo; Truman, Richard W; Goulart, Isabela Maria B; Vissa, Varalakshmi; Li, Wei; Matsuoka, Masanori; Suffys, Philip; Fontes, Amanda B; Rosa, Patricia S; Scollard, David M; Williams, Diana L

2017-06-01

Real-Time PCR-High Resolution Melting (qPCR-HRM) analysis has been recently described for rapid drug susceptibility testing (DST) of Mycobacterium leprae. The purpose of the current study was to further evaluate the validity, reliability, and accuracy of this assay for M. leprae DST in clinical specimens. The specificity and sensitivity for determining the presence and susceptibility of M. leprae to dapsone based on the folP1 drug resistance determining region (DRDR), rifampin (rpoB DRDR) and ofloxacin (gyrA DRDR) was evaluated using 211 clinical specimens from leprosy patients, including 156 multibacillary (MB) and 55 paucibacillary (PB) cases. When comparing the results of qPCR-HRM DST and PCR/direct DNA sequencing, 100% concordance was obtained. The effects of in-house phenol/chloroform extraction versus column-based DNA purification protocols, and that of storage and fixation protocols of specimens for qPCR-HRM DST, were also evaluated. qPCR-HRM results for all DRDR gene assays (folP1, rpoB, and gyrA) were obtained from both MB (154/156; 98.7%) and PB (35/55; 63.3%) patients. All PCR negative specimens were from patients with low numbers of bacilli enumerated by an M. leprae-specific qPCR. We observed that frozen and formalin-fixed paraffin embedded (FFPE) tissues or archival Fite's stained slides were suitable for HRM analysis. Among 20 mycobacterial and other skin bacterial species tested, only M. lepromatosis, highly related to M. leprae, generated amplicons in the qPCR-HRM DST assay for folP1 and rpoB DRDR targets. Both DNA purification protocols tested were efficient in recovering DNA suitable for HRM analysis. However, 3% of clinical specimens purified using the phenol/chloroform DNA purification protocol gave false drug resistant data. DNA obtained from freshly frozen (n = 172), formalin-fixed paraffin embedded (FFPE) tissues (n = 36) or archival Fite's stained slides (n = 3) were suitable for qPCR-HRM DST analysis. The HRM-based assay was also able to

Weights of Evidence Method for Landslide Susceptibility Mapping in Takengon, Central Aceh, Indonesia

Science.gov (United States)

Pamela; Sadisun, Imam A.; Arifianti, Yukni

2018-02-01

Takengon is an area prone to earthquake disaster and landslide. On July 2, 2013, Central Aceh earthquake induced large numbers of landslides in Takengon area, which resulted in casualties of 39 people. This location was chosen to assess the landslide susceptibility of Takengon, using a statistical method, referred to as the weight of evidence (WoE). This WoE model was applied to indicate the main factors influencing the landslide susceptible area and to derive landslide susceptibility map of Takengon. The 251 landslides randomly divided into two groups of modeling/training data (70%) and validation/test data sets (30%). Twelve thematic maps of evidence are slope degree, slope aspect, lithology, land cover, elevation, rainfall, lineament, peak ground acceleration, curvature, flow direction, distance to river and roads used as landslide causative factors. According to the AUC, the significant factor controlling the landslide is the slope, the slope aspect, peak ground acceleration, elevation, lithology, flow direction, lineament, and rainfall respectively. Analytical result verified by using test data of landslide shows AUC prediction rate is 0.819 and AUC success rate with all landslide data included is 0.879. This result showed the selective factors and WoE method as good models for assessing landslide susceptibility. The landslide susceptibility map of Takengon shows the probabilities, which represent relative degrees of susceptibility for landslide proneness in Takengon area.

Spectrophotometric reading of EUCAST antifungal susceptibility testing of Aspergillus fumigatus

DEFF Research Database (Denmark)

Meletiadis, J.; Leth Mortensen, K.; Verweij, P. E.

2017-01-01

with spectrophotometrically determined MICs and essential (±1 twofold dilution) and categorical (susceptible/intermediate/resistant or wild-type/non-wild-type) agreement was calculated. Spectrophotometric data were analysed with regression analysis using the Emax model, and the effective concentration corresponding to 5% (EC......5) was estimated. Results Using the 5% cut-off, high essential (92%–97%) and categorical (93%–99%) agreement (

Antimicrobial susceptibility testing before first-line treatment for Helicobacter pylori infection in patients with dual or triple antibiotic resistance.

Science.gov (United States)

Cosme, Angel; Montes, Milagrosa; Ibarra, Begoña; Tamayo, Esther; Alonso, Horacio; Mendarte, Usua; Lizasoan, Jacobo; Herreros-Villanueva, Marta; Bujanda, Luis

2017-05-14

To evaluate the efficacy of antimicrobial susceptibility-guided therapy before first-line treatment for infection in patients with dual or triple antibiotic resistance. A total of 1034 patients infected by Helicobacter pylori ( H. pylori ) during 2013-2014 were tested for antimicrobial susceptibility. 157 of 1034 (15%) patients showed resistance to two (127/1034; 12%) and to three (30/1034; 3%) antibiotics. Sixty-eight patients with dual H. pylori -resistance (clarithromycin, metronidazole or levofloxacin) were treated for 10 d with triple therapies: OAL (omeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and levofloxacin 500 mg b.i.d.) 43 cases, OAM (omeprazole 20 mg b.i.d., amoxicillin 1 g b.i.d., and metronidazole 500 mg b.i.d.) 12 cases and OAC (omeprazole 20 mg b.id., amoxicillin 1 g b.i.d., and clarithromycin 500 mg b.i.d.) 13 cases based on the antimicrobial susceptibility testing. Twelve patients showed triple H. pylori -resistance (clarithromycin, metronidazole and levofloxacin) and received for 10 d triple therapy with OAR (omeprazole 20 mg b.id., amoxicillin 1 g b.i.d., and rifabutin 150 mg b.i.d.). Eradication was confirmed by 13C-urea breath test. Adverse effects and compliance were assessed by a questionnaire. Intention-to-treat eradication rates were: OAL (97.6%), OAM (91.6%), OAC (92.3%) and OAR (58.3%). Cure rate was significantly higher in naïve patients treated with OAR-10 compared to patients who had two or three previous treatment failures (83% vs 33%). Adverse events rates for OAL, OAM, OAC and OAR were 22%, 25%, 23% and 17%, respectively, all of them mild-moderate. Antimicrobial susceptibility-guided triple therapies during 10 d for first-line treatment leads to an eradication rate superior to 90% in patients with dual antibiotic H. pylori resistance.

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...... 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...

Species Distribution and Susceptibility to Azoles of Vaginal Yeasts Isolated Prostitutes

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Norma T. Gross

2007-01-01

Full Text Available Objective. We investigated the use of miconazole among female prostitutes in Costa Rica as well as the distribution of vaginal yeasts and the susceptibility pattern to azoles of strains obtained from this population. Our intention was to relate a frequent use of miconazole to occurrence of vaginal yeasts resistant to azoles. Methods. Vaginal samples were taken from 277 patients that have previously used azoles. Vaginal swabs were obtained for direct microscopy and culture. Yeast isolates were identified by germ tube test and assimilation pattern. Susceptibility testing was determined using a tablet diffusion method. Results. The number of clinical Candida isolates (one from each patient was 57 (20.6%. C. albicans was the predominant species (70%, followed by C. parapsilosis (12%, C. tropicalis (5.3%, C. glabrata and C. famata (3.5% each, C. krusei, C. inconspicua and C. guilliermondii (1.7% each. The majority of vaginal Candida isolates were susceptible to ketoconazole (91%, fluconazole (96.5%, and itraconazole (98%. A lower susceptibility of some isolates to miconazole (63% was observed as compared to the other azoles tested. Moreover, the strains, nonsusceptible to miconazole, were more often obtained from patients that have used this antifungal at least four times within the last year before taking the samples as compared to those with three or less treatments (P<.01. Conclusion. An indiscriminate use of miconazole, such as that observed among female prostitutes in Costa Rica, results in a reduced susceptibility of vaginal yeasts to miconazole but not to other azoles.

Experience of parental cancer in childhood is a risk factor for psychological distress during genetic cancer susceptibility testing

NARCIS (Netherlands)

van Oostrom, I.; Meijers-Heijboer, H.; Duivenvoorden, H. J.; Brocker-Vriends, A. H. J. T.; van Asperen, C. J.; Sijmons, R. H.; Seynaeve, C.; Van Gool, A. R.; Klijn, J. G. M.; Tibben, A.

Background: This study explores the effect of age at the time of parental cancer diagnosis or death on psychological distress and cancer risk perception in individuals undergoing genetic testing for a specific cancer susceptibility. Patients and methods: Cancer-related distress, worry and risk

The effect of molybdenum addition on SCC susceptibility of stainless steels in oxygenated high temperature water

International Nuclear Information System (INIS)

Akashi, Masatsune; Kawamoto, Teruaki

1978-01-01

The effect of molybdenum addition on the SCC susceptibility of sensitized stainless steel in oxygenated high temperature water has been studied through the creviced bent beam SCC test (CBB test) and A262E intergranular corrosion test. The molybdenum addition improved the SCC susceptibility of sensitized stainless steels in oxygenated high temperature water not only by delaying the sensitization at lower temperatures but also by increasing the material resistance to the SCC under a given degree of sensitization. These laboratory test results reveal that the molybdenum addition is quite beneficial for improving the SCC susceptibility of stainless steel pipe weld joints in boiling water reactor environment. (auth.)

Antimicrobial Susceptibility Pattern in Diabetic Foot Ulcer: A Pilot Study

African Journals Online (AJOL)

Antimicrobial susceptibility test was performed by disc diffusion techniques according to Clinical and. Laboratory Standards Institute guidelines. Results: Of the 108 ..... antibiotics tested. This was in accordance with multidrug-resistant. Acinetobacter isolates from Bansal, et al. study.[4] The main limitations of our study are a ...

Landslide susceptibility map: from research to application

Science.gov (United States)

Fiorucci, Federica; Reichenbach, Paola; Ardizzone, Francesca; Rossi, Mauro; Felicioni, Giulia; Antonini, Guendalina

2014-05-01

Susceptibility map is an important and essential tool in environmental planning, to evaluate landslide hazard and risk and for a correct and responsible management of the territory. Landslide susceptibility is the likelihood of a landslide occurring in an area on the basis of local terrain conditions. Can be expressed as the probability that any given region will be affected by landslides, i.e. an estimate of "where" landslides are likely to occur. In this work we present two examples of landslide susceptibility map prepared for the Umbria Region and for the Perugia Municipality. These two maps were realized following official request from the Regional and Municipal government to the Research Institute for the Hydrogeological Protection (CNR-IRPI). The susceptibility map prepared for the Umbria Region represents the development of previous agreements focused to prepare: i) a landslide inventory map that was included in the Urban Territorial Planning (PUT) and ii) a series of maps for the Regional Plan for Multi-risk Prevention. The activities carried out for the Umbria Region were focused to define and apply methods and techniques for landslide susceptibility zonation. Susceptibility maps were prepared exploiting a multivariate statistical model (linear discriminant analysis) for the five Civil Protection Alert Zones defined in the regional territory. The five resulting maps were tested and validated using the spatial distribution of recent landslide events that occurred in the region. The susceptibility map for the Perugia Municipality was prepared to be integrated as one of the cartographic product in the Municipal development plan (PRG - Piano Regolatore Generale) as required by the existing legislation. At strategic level, one of the main objectives of the PRG, is to establish a framework of knowledge and legal aspects for the management of geo-hydrological risk. At national level most of the susceptibility maps prepared for the PRG, were and still are obtained

Antimicrobial susceptibility of anaerobic bacteria in New Zealand: 1999-2003.

Science.gov (United States)

Roberts, Sally A; Shore, Keith P; Paviour, Susan D; Holland, David; Morris, Arthur J

2006-05-01

Routine susceptibility testing of all anaerobic organisms is not advocated, but it is useful for laboratories to test periodically for anaerobic organisms and provide local susceptibility data to guide therapy. This study reports the national trend of antibiotic susceptibility of clinically significant anaerobes in New Zealand. Clinical isolates were tested using standardized methods against a range of antibiotics commonly used to treat anaerobic infections. Susceptibility was determined using NCCLS criteria. The change in susceptibility trends between this study and earlier studies was measured by comparing the geometric mean of the MIC. A total of 364 anaerobes were tested. Penicillin had poor activity against Bacteroides spp., Prevotella spp., Eubacterium spp., Clostridium tertium and Veillonella spp. In general, Fusobacterium spp., Bacteroides ureolyticus, Propionibacterium spp., Clostridium perfringens and anaerobic streptococci isolates, with the exception of Peptostreptococcus anaerobius, were penicillin susceptible. Amoxicillin/clavulanate showed good activity against most anaerobes, but resistance was seen with Bacteroides fragilis group and P. anaerobius isolates. Cefoxitin was more active than cefotetan, particularly against non-B. fragilis species, Eubacterium spp. and P. anaerobius. Meropenem and imipenem showed good activity against all anaerobes, with only 2 and 4% of Bacteroides spp., respectively, showing resistance. With the exception of Propionibacterium acnes isolates, which are predictably resistant, metronidazole was active against all anaerobes tested. There has been little change in susceptibility since 1997. Metronidazole, cefoxitin, piperacillin/tazobactam and amoxicillin/clavulanate remain good empirical choices when anaerobes are expected in our setting. No clinically relevant changes in susceptibility over time were found.

Urinary Bacterial Profile and Antibiotic Susceptibility Pattern among ...

African Journals Online (AJOL)

Organisms were identified from mid-stream clean catch urine samples and antibiotic susceptibility was performed using bacteriological standard tests. Data were collected using structured questionnaires and were processed and analyzed using SPSS for Windows version 16. Results: Out of 367 pregnant women, 37 were ...

Experience of parental cancer in childhood is a risk factor for psychological distress during genetic cancer susceptibility testing

NARCIS (Netherlands)

van Oostrom, I.; Meijers-Heijboer, H.; Duivenvoorden, H. J.; Bröcker-Vriends, A. H. J. T.; van Asperen, C. J.; Sijmons, R. H.; Seynaeve, C.; van Gool, A. R.; Klijn, J. G. M.; Tibben, A.

2006-01-01

This study explores the effect of age at the time of parental cancer diagnosis or death on psychological distress and cancer risk perception in individuals undergoing genetic testing for a specific cancer susceptibility. Cancer-related distress, worry and risk perception were assessed in 271

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.

MASTER: a model to improve and standardize clinical breakpoints for antimicrobial susceptibility testing using forecast probabilities.

Science.gov (United States)

Blöchliger, Nicolas; Keller, Peter M; Böttger, Erik C; Hombach, Michael

2017-09-01

The procedure for setting clinical breakpoints (CBPs) for antimicrobial susceptibility has been poorly standardized with respect to population data, pharmacokinetic parameters and clinical outcome. Tools to standardize CBP setting could result in improved antibiogram forecast probabilities. We propose a model to estimate probabilities for methodological categorization errors and defined zones of methodological uncertainty (ZMUs), i.e. ranges of zone diameters that cannot reliably be classified. The impact of ZMUs on methodological error rates was used for CBP optimization. The model distinguishes theoretical true inhibition zone diameters from observed diameters, which suffer from methodological variation. True diameter distributions are described with a normal mixture model. The model was fitted to observed inhibition zone diameters of clinical Escherichia coli strains. Repeated measurements for a quality control strain were used to quantify methodological variation. For 9 of 13 antibiotics analysed, our model predicted error rates of  0.1% for ampicillin, cefoxitin, cefuroxime and amoxicillin/clavulanic acid. Increasing the susceptible CBP (cefoxitin) and introducing ZMUs (ampicillin, cefuroxime, amoxicillin/clavulanic acid) decreased error rates to < 0.1%. ZMUs contained low numbers of isolates for ampicillin and cefuroxime (3% and 6%), whereas the ZMU for amoxicillin/clavulanic acid contained 41% of all isolates and was considered not practical. We demonstrate that CBPs can be improved and standardized by minimizing methodological categorization error rates. ZMUs may be introduced if an intermediate zone is not appropriate for pharmacokinetic/pharmacodynamic or drug dosing reasons. Optimized CBPs will provide a standardized antibiotic susceptibility testing interpretation at a defined level of probability. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For

Combination of statistical and physically based methods to assess shallow slide susceptibility at the basin scale

Science.gov (United States)

Oliveira, Sérgio C.; Zêzere, José L.; Lajas, Sara; Melo, Raquel

2017-07-01

Approaches used to assess shallow slide susceptibility at the basin scale are conceptually different depending on the use of statistical or physically based methods. The former are based on the assumption that the same causes are more likely to produce the same effects, whereas the latter are based on the comparison between forces which tend to promote movement along the slope and the counteracting forces that are resistant to motion. Within this general framework, this work tests two hypotheses: (i) although conceptually and methodologically distinct, the statistical and deterministic methods generate similar shallow slide susceptibility results regarding the model's predictive capacity and spatial agreement; and (ii) the combination of shallow slide susceptibility maps obtained with statistical and physically based methods, for the same study area, generate a more reliable susceptibility model for shallow slide occurrence. These hypotheses were tested at a small test site (13.9 km2) located north of Lisbon (Portugal), using a statistical method (the information value method, IV) and a physically based method (the infinite slope method, IS). The landslide susceptibility maps produced with the statistical and deterministic methods were combined into a new landslide susceptibility map. The latter was based on a set of integration rules defined by the cross tabulation of the susceptibility classes of both maps and analysis of the corresponding contingency tables. The results demonstrate a higher predictive capacity of the new shallow slide susceptibility map, which combines the independent results obtained with statistical and physically based models. Moreover, the combination of the two models allowed the identification of areas where the results of the information value and the infinite slope methods are contradictory. Thus, these areas were classified as uncertain and deserve additional investigation at a more detailed scale.

A Novel and Validated Protocol for Performing MIC Tests to Determine the Susceptibility of Piscirickettsia salmonis Isolates to Florfenicol and Oxytetracycline

Directory of Open Access Journals (Sweden)

Sergio Contreras-Lynch

2017-07-01

Full Text Available This paper presents a validated protocol, using a novel, specifically formulated medium, to perform broth microdilution antimicrobial susceptibility assays of the salmonid bacterial pathogen Piscirickettsia salmonis. The minimum inhibitory concentrations (MIC for florfenicol and oxytetracycline against 58 P. salmonis isolates recovered from various outbreaks occurred in Chilean salmonid farms were determined using this protocol. Normalized resistance interpretation (NRI analysis was applied to these data to calculate appropriate protocol-specific epidemiological cut-off values. These cut-off values allow the isolates to be categorized as either fully susceptible wild type (WT members of this species, or as manifesting reduced susceptibility non-wild type (NWT. The distribution of MIC values of florfenicol was bimodal and the distribution of the normalized values for the putative WT observation had a standard deviation of 0.896 log2 μg mL-1. This analysis calculated a cut-off value of ≤0.25 μg mL-1 and categorized 33 (56% of the isolates as manifesting reduced susceptibility to florfenicol. For the oxytetracycline MIC data the NRI analysis also treated the distribution as bimodal. The distribution of the normalized values for the putative WT observation had a standard deviation of 0.951 log2 μg mL-1. This analysis gave a cut-off value of ≤0.5 μg mL-1 and categorized five isolates (9% as manifesting reduced susceptibility to oxytetracycline. The susceptibility testing protocol developed in this study was capable of generating MIC data from all the isolates tested. On the basis of the precision of the data it generated, and the degree of separation of values for WT and NWT it achieved, it is argued that this protocol has the performance characteristics necessary for it to be considered as a standard protocol.

In Vitro Antibiotic Susceptibility Studies Of Bacteria Associated With ...

African Journals Online (AJOL)

In vitro tests of the susceptibility of isolates of bacterial keratitis pathogens to antibiotics were carried out in this study. Staphylococcus aureus was the most frequently isolated organisms followed by Pseudomonas aeruginosa and Streptococcus pneumoniae. Antibiotic sensitivity testing showed a high susceptibility to ...

Use of the National Committee for Clinical Laboratory Standards Guidelines for Disk Diffusion Susceptibility Testing in New York State Laboratories

Science.gov (United States)

Kiehlbauch, Julia A.; Hannett, George E.; Salfinger, Max; Archinal, Wendy; Monserrat, Catherine; Carlyn, Cynthia

2000-01-01

Accurate antimicrobial susceptibility testing is vital for patient care and surveillance of emerging antimicrobial resistance. The National Committee for Clinical Laboratory Standards (NCCLS) outlines generally agreed upon guidelines for reliable and reproducible results. In January 1997 we surveyed 320 laboratories participating in the New York State Clinical Evaluation Program for General Bacteriology proficiency testing. Our survey addressed compliance with NCCLS susceptibility testing guidelines for bacterial species designated a problem (Staphylococcus aureus and Enterococcus species) or fastidious (Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria gonorrhoeae) organism. Specifically, we assessed compliance with guidelines for inoculum preparation, medium choice, number of disks per plate, and incubation conditions for disk diffusion tests. We also included length of incubation for S. aureus and Enterococcus species. We found overall compliance with the five characteristics listed above in 80 of 153 responding laboratories (50.6%) for S. aureus and 72 of 151 (47.7%) laboratories for Enterococcus species. The most common problem was an incubation time shortened to less than 24 h. Overall compliance with the first four characteristics was reported by 92 of 221 (41.6%) laboratories for S. pneumoniae, 49 of 163 (30.1%) laboratories for H. influenzae, and 11 of 77 (14.3%) laboratories for N. gonorrhoeae. Laboratories varied from NCCLS guidelines by placing an excess number of disks per plate. Laboratories also reported using alternative media for Enterococcus species, N. gonorrhoeae, and H. influenzae. This study demonstrates a need for education among clinical laboratories to increase compliance with NCCLS guidelines. PMID:10970381

Antibiotic susceptibility of methicillin-resistant staphylococci (MRS) of food origin: A comparison of agar disc diffusion method and a commercially available miniaturized test.

Science.gov (United States)

Buzón-Durán, Laura; Capita, Rosa; Alonso-Calleja, Carlos

2018-06-01

Methicillin-resistant staphylococci (MRS) are a major concern to public and animal health. Thirty MRS (Staphylococcus aureus, S. cohnii, S. epidermidis, S. haemolyticus, S. hominis, S. lentus, S. lugdunensis, S. sciuri, and S. xylosus) isolates from meat and poultry preparations were tested for antimicrobial susceptibility to 11 antimicrobials (belonging to seven different categories) of clinical significance using both the standard agar disc diffusion method and a commercially available miniaturized system (Sensi Test Gram-positive). It is worth stressing that 16 isolates (53.33%) exhibited an extensively drug-resistant phenotype (XDR). The average number of resistances per strain was 4.67. These results suggest that retail meat and poultry preparations are a likely vehicle for the transmission of multi-drug resistant MRS. Resistance to erythromycin was the commonest finding (76.67% of strains), followed by tobramycin, ceftazidime (66.67%), ciprofloxacin (56.67%) and fosfomycin (53.33%). An agreement (kappa coefficient) of 0.64 was found between the two testing methods. Using the agar disc diffusion as the reference method, the sensitivity, specificity and accuracy of the miniaturized test were 98.44%, 69.44% and 83.33%, respectively. Most discrepancies between the two methods were due to isolates that were susceptible according to the disc diffusion method but resistant according to the miniaturized test (false positives). Copyright © 2017. Published by Elsevier Ltd.

Antimicrobial Susceptibility Patterns of Brachyspira Species Isolated in Taiwan.

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Yeh, Jih-Ching; Lo, Dan-Yuan; Chang, Shao-Kuang; Kuo, Hung-Chih

2018-03-13

Some members of the Brachyspira genus cause diseases such as swine dysentery (SD) and porcine intestinal (or colonic) spirochetosis. Severe economic losses are caused by decreased feed intake and increased feed conversion ratio, as well as costs associated with treatment and death. A loss of clinical efficacy of some antimicrobial agents authorized for treating SD has been observed in many countries. The aim of this study was to analyze the antimicrobial susceptibility of Brachyspira isolated from Taiwan and to investigate the mechanism of decreased susceptibility to macrolides. A total of 55 Brachyspira isolates obtained from the grower-finisher period were evaluated in this study. These isolates included B. hyodysenteriae (n = 37), B. murdochii (n = 11), B. pilosicoli (n = 5), B. intermedia (n = 1), and B. innocens (n = 1). Antimicrobial susceptibility testing was performed to examine 12 selected antimicrobial agents. The results showed that the 50% and 90% minimum inhibitory concentration (MIC) values of the tested macrolides were all >256 μg/ml. The MIC 50 of lincomycin, tiamulin, carbadox, olaquindox, ampicillin, amoxicillin, doxycycline, oxytetracycline, and gentamicin were 32, 1, ≤0.125, ≤0.125, 0.5, 0.25, 2, 2, and 2 μg/ml. The genetic basis of the decreased susceptibility to tylosin and lincomycin in Brachyspira spp. was investigated and the results showed a possible connection to the mutations at position A2058 and G2032 of the 23S rRNA gene. These findings demonstrated that, in Taiwan, there may be a decrease in susceptibility of Brachyspira spp. to antimicrobials commonly used for the treatment of SD.

Susceptibility Breakpoint for Enrofloxacin against Swine Salmonella spp.

Science.gov (United States)

Hao, Haihong; Pan, Huafang; Ahmad, Ijaz; Cheng, Guyue; Wang, Yulian; Dai, Menghong; Tao, Yanfei; Chen, Dongmei; Peng, Dapeng; Liu, Zhenli

2013-01-01

Susceptibility breakpoints are crucial for prudent use of antimicrobials. This study has developed the first susceptibility breakpoint (MIC ≤ 0.25 μg/ml) for enrofloxacin against swine Salmonella spp. based on wild-type cutoff (COWT) and pharmacokinetic-pharmacodynamic (PK-PD) cutoff (COPD) values, consequently providing a criterion for susceptibility testing and clinical usage of enrofloxacin. PMID:23784134

Susceptibility weighted imaging (SWI) of the kidney at 3 T. Initial results

International Nuclear Information System (INIS)

Mie, Moritz B.; Zoellner, Frank G.; Heilmann, Melanie; Schad, Lothar R.; Nissen, Johanna C.; Schoenberg, Stefan O.; Michaely, Henrik J.

2010-01-01

Susceptibility weighted imaging provides diagnostic information in strokes, hemorrhages, and cerebral tumors and has proven to be a valuable tool in imaging venous vessels in the cerebrum. The SWI principle is based on the weighting of T 2 * weighted magnitude images with a phase mask, therewith improving image contrast of veins or neighbouring structures of different susceptibility, in general. T 2 * weighted MRI is already used for assessment of kidney function. In this paper, the feasibility of SWI on kidneys was investigated. Translation of SWI from the brain to the kidneys comes along with two main challenges: (i) organ motion due to breathing and (ii) a higher oxygenation level of renal veins compared to the brain. To handle these problems, the acquisition time has been cut down to allow for breath-hold examinations, and different post-processing methods including a new phase mask were investigated to visualize renal veins. Results showed that by a new post-processing strategy SWI contrast was enhanced on average by a factor of 1.33 compared to the standard phase mask. In summary, initial experiences of SWI on the kidneys demonstrated the feasibility. However, further technical developments have to be performed to make this technology applicable in clinical abdominal MRI. (orig.)

Methicillin-resistant Staphylococcus aureus isolates with SCCmec type V and spa types t437 or t1081 associated to discordant susceptibility results between oxacillin and cefoxitin, Central Taiwan.

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Ho, Cheng-Mao; Lin, Chien-Yu; Ho, Mao-Wang; Lin, Hsiao-Chuan; Chen, Chao-Jung; Lin, Lee-Chung; Lu, Jang-Jih

2016-12-01

Staphylococcus aureus isolates with discordant susceptibility results between oxacillin and cefoxitin obtained using automated microbiology systems are infrequently observed. From April 2013 to December 2014, 1956 methicillin-resistant S. aureus (MRSA) and 1761 methicillin-susceptible S. aureus isolates were obtained from different patients. Forty isolates (1.1% and 2% in case of S. aureus and MRSA, respectively) with discordant susceptibility results (oxacillin susceptible and cefoxitin resistant) and carrying mecA gene were obtained. Except 2 SCCmec type IV isolates, 38 MRSA isolates were all SCCmec type V (V T or non-V T ), which were further divided into V T (n=22) and non-V T (n=16). The most common spa type in V T and non-V T isolates were t437 (n=19) and t1081 (n=13), respectively. Only 55% of patients received effective antimicrobial agents; 2 mortalities were not attributable to MRSA infection. Using standard agar dilution, 17 MRSA isolates (0.46% and 0.87% in case of S. aureus and MRSA, respectively) had oxacillin MIC in the susceptible ranges (oxacillin-susceptible MRSA [OS-MRSA]); all carried SCCmec type V (V T , n=8; non-V T , n=9). The most common spa-MLST types of OS-MRSA in V T and non-V T were t437-ST59 (n=4) and t1081-ST45 (n=7), respectively. Concomitant testing by both cefoxitin- and oxacillin-based methods is a practical strategy for OS-MRSA detection in the clinical laboratories. Continuous monitoring of OS-MRSA isolates is necessary to elucidate their impact in clinical infectious diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

In vitro antifungal susceptibility testing of Scopulariopsis brevicaulis strains using agar diffusion method.

Science.gov (United States)

Skóra, Magdalena; Macura, Anna B

2011-01-01

The genus Scopulariopsis is a common soil saprotroph and has been isolated from air, organic waste and also from plant, animal and human tissues. Scopulariopsis has mainly been associated in humans with superficial mycoses, but it has also been described as the cause of subcutaneous and invasive infections. The most common aetiological agent of infections in humans is Scopulariopsis brevicaulis. This species has been reported to be resistant in vitro to broad-spectrum antifungal agents available today. The aim of the study was to establish in vitro antifungal susceptibility of 35 S. brevicaulis strains against amphotericin B (AMB), flucytosine (FC), caspofungin (CAS), terbinafine (TER), ciclopirox (CIC), voriconazole (VOR), clotrimazole (CTR), miconazole (MCZ), econazole (ECO), ketoconazole (KET), itraconazole (ITR), and fluconazole (FLU). Antifungal susceptibility tests were evaluated by an agar diffusion method (Neo-Sensitabs, Rosco, Denmark). AMB, FC, CAS, ITR and FLU showed no antifungal activity against S. brevicaulis. TER, CIC, CTR, KET, VOR, ECO, and MCZ revealed inhibitory activity for S. brevicaulis, but it varied for each of the drugs. The best antifungal effect was observed for TER and CIC. All isolates had large inhibition zones for TER and CIC. CTR was also inhibitory for all tested S. brevicaulis isolates, but the diameters of inhibition zones were smaller than for TER and CIC. Nearly 89% isolates showed inhibition zones for KET and the mean diameter of the inhibition zone was comparable to CTR. The least antifungal activity exhibited VQR, ECO and MCZ. Because of the multiresistance of S. brevicaulis, infections due to this species may not respond to particular antifungal treatment and other therapeutic approaches should be considered, e.g., combined therapy and/or surgery.

Insecticide susceptibility of Aedes aegypti populations from Senegal and Cape Verde Archipelago.

Science.gov (United States)

Dia, Ibrahima; Diagne, Cheikh Tidiane; Ba, Yamar; Diallo, Diawo; Konate, Lassana; Diallo, Mawlouth

2012-10-22

Two concomitant dengue 3 (DEN-3) epidemics occurred in Cape Verde Archipelago and Senegal between September and October 2009. Aedes aegypti was identified as the vector of these epidemics as several DEN-3 virus strains were isolated from this species in both countries. The susceptibility to pyrethroids, organochlorine, organophosphates and carbamate was investigated in two field strains of Aedes aegypti from both countries using WHO diagnostic bioassay kits in order to monitor their the current status of insecticide susceptibility. The two tested strains were highly resistant to DDT. The Cape Verde strain was found to be susceptible to all others tested insecticides except for propoxur 0.1%, which needs further investigation. The Dakar strain was susceptible to fenitrothion 1% and permethrin 0.75%, but displayed reduced susceptibility to deltamethrin, lambda-cyhalothrin and propoxur. As base-line results, our observations stress a careful management of insecticide use for the control of Ae. aegypti. Indeed, they indicate that DDT is no longer efficient for the control of Ae. aegypti populations in Cape Verde and Dakar and further suggest a thorough follow-up of propoxur susceptibility status in both sites and that of deltamethrin and lambda-cyhalothrin in Ae. aegypti populations in Dakar. Thus, regular monitoring of susceptibility is greatly needed as well as the knowing if this observed resistance/susceptibility is focal or not and for observed resistance, the use of biochemical methods is needed with detailed comparison of resistance levels over a large geographic area. Aedes aegypti, Insecticides, Susceptibility, Cape Verde, Senegal.

Changes to perceptions of the pros and cons of genetic susceptibility testing after APOE genotyping for Alzheimer disease risk

Science.gov (United States)

Christensen, Kurt D.; Roberts, J. Scott; Uhlmann, Wendy R.; Green, Robert C.

2011-01-01

Purpose Perceptions about the pros and cons of genetic susceptibility testing are among the best predictors of test utilization. How actual testing changes such perceptions has yet to be examined. Methods In a clinical trial, first-degree relatives of patients with Alzheimer disease received genetic risk assessments for Alzheimer disease including APOE disclosure. Participants rated 11 possible benefits associated with genetic testing (pros) and 10 risks or limitations (cons) before genetic risk disclosure and again 12 months afterward. Results Pros were rated higher than cons at baseline (3.53 vs. 1.83, P cons did not change (1.88 vs. 1.83, P = 0.199) except for a three-item discrimination subscale which increased (2.07 vs. 1.92, P = 0.012). Among specific pros and cons, three items related to prevention and treatment changed the most. Conclusion The process of APOE genetic risk assessment for Alzheimer disease sensitizes some to its limitations and the risks of discrimination; however, 1-year after disclosure, test recipients still consider the pros to strongly outweigh the cons. PMID:21270636

Susceptibility of pregnant women to toxoplasma infection--potential benefits for newborn screening.

LENUS (Irish Health Repository)

Ferguson, W

2008-08-20

Congenital toxoplasmosis (CT) arises as a result of new acquisition of Toxoplasma infection by a susceptible woman during pregnancy. Early detection of CT through neonatal screening programmes could optimize management and improve infant outcome. This study sought to estimate the prevalence of Toxoplasma susceptibility in pregnant women. As detection of Toxoplasma antibodies in neonatal blood reflects maternal exposure history, maternal antibody seroprevalence was determined using anonymized residual blood from newborn screening cards. A total of 20,252 cards were tested in 1 year. 4,991 (24.6%) cards tested positive for Toxoplasma antibody. Results were stratified by county. Toxoplasma antibody seroprevalence rates of 25% indicated that Toxoplasma infection is common in Ireland and that up to 75% of women remain susceptible to primary infection during pregnancy. This study aimed to a) determine the seroprevalence of Toxoplasma antibody in pregnant women, and hence b) estimate the risk for acquisition of primary toxoplasmosis in pregnancy in order to support an application to fund a pilot newborn screening programme.

Comparison of the Vitek 2 yeast susceptibility system with CLSI microdilution for antifungal susceptibility testing of fluconazole and voriconazole against Candida spp., using new clinical breakpoints and epidemiological cutoff values.

Science.gov (United States)

Pfaller, Michael A; Diekema, Daniel J; Procop, Gary W; Rinaldi, Michael G

2013-09-01

A commercially available, fully automated yeast susceptibility test system (Vitek 2; bioMérieux, Marcy d'Etoile, France) was compared in 3 different laboratories with the Clinical and Laboratory Standards Institute (CLSI) reference microdilution (BMD) method by testing 2 quality control strains, 10 reproducibility strains, and 425 isolates of Candida spp. against fluconazole and voriconazole. Reference CLSI BMD MIC endpoints and Vitek 2 MIC endpoints were read after 24 hours and 9.1-27.1 hours incubation, respectively. Excellent essential agreement (within 2 dilutions) between the reference and Vitek 2 MICs was observed for fluconazole (97.9%) and voriconazole (96.7%). Categorical agreement (CA) between the 2 methods was assessed using the new species-specific clinical breakpoints (CBPs): susceptible (S) ≤2 μg/mL, susceptible dose-dependent (SDD) 4 μg/mL, and resistant (R) ≥8 μg/mL for fluconazole and Candida albicans, Candida tropicalis, and Candida parapsilosis and ≤32 μg/mL (SDD), ≥64 μg/mL (R) for Candida glabrata; S ≤0.12 μg/mL, SDD 0.25-0.5 μg/mL, R ≥1 μg/mL for voriconazole and C. albicans, C. tropicalis, and C. parapsilosis, and ≤0.5 μg/mL (S), 1 μg/mL (SDD), ≥2 μg/mL (R) for Candida krusei. The epidemiological cutoff value (ECV) of 0.5 μg/mL for voriconazole and C. glabrata was used to differentiate wild-type (WT; MIC ≤ ECV) from non-WT (MIC > ECV) strains of this species. Due to the lack of CBPs for the less common species, the ECVs for fluconazole and voriconazole, respectively, were used for Candida lusitaniae (2 μg/mL and 0.03 μg/mL), Candida dubliniensis (0.5 μg/mL and 0.03 μg/mL), Candida guilliermondii (8 μg/mL and 0.25 μg/mL), and Candida pelliculosa (4 μg/mL and 0.25 μg/mL) to categorize isolates of these species as WT and non-WT. CA between the 2 methods was 96.8% for fluconazole and 96.5% for voriconazole with less than 1% very major errors and 1.3-3.0% major errors. The Vitek 2 yeast susceptibility system

In vitro susceptibility of bovine mastitis pathogens to a combination of penicillin and framycetin: development of interpretive criteria for testing by broth microdilution and disk diffusion.

Science.gov (United States)

Pillar, C M; Stoneburner, A; Shinabarger, D L; Abbeloos, E; Goby, L; Bradley, Andrew J

2014-10-01

Dry cow therapy is an important part of mastitis control. This therapy typically consists of an antibiotic or antibiotics administered at a single dose by intramammary infusion at dry off to treat or prevent infection by prevalent mastitis pathogens. A combination dry cow therapy consisting of the active components penicillin and framycetin is currently used in several countries. Despite its use, standardized methods for the susceptibility testing of this combination against mastitis pathogens have not been established. In this study, which used Clinical and Laboratory Standards Institute methodology, preliminary interpretive criteria for the broth microdilution minimum inhibitory concentration (MIC) testing of mastitis pathogens to penicillin combined with framycetin (2:1 wt/wt) were established based on the amount of drug achieved and maintained postadministration in the udder. Based on resulting MIC distributions of recent veterinary field isolates and a subset of isolates preselected for resistance to β-lactams or aminoglycosides and concentrations achieved postadministration, criteria for broth microdilution testing of the combination (susceptible, intermediate, resistant in micrograms per milliliter) were set as follows: Escherichia coli ≤8/4, 16/8, ≥32/16; Staphylococcus spp. ≤2/1, 4/2-8/4, >16/8; Streptococcus uberis and Streptococcus dysgalactiae 4/2. A disk diffusion test using disks containing 100 μg of framycetin and 10 IU of penicillin was also developed, and preliminary interpretive criteria (susceptible, intermediate, resistant in millimeters) were set based on correlation to broth MIC values and the minimization of interpretive errors between isolates tested concurrently by broth microdilution and disk diffusion as follows: E. coli ≥18, 16-17, ≤15; Staphylococcus spp. ≥21, 18-20, ≤17; Strep. uberis and Strep. dysgalactiae ≥21, 19-20, ≤18. In addition, ranges for the quality control of the testing of this combination by both broth

Antimicrobial Susceptibility of Enteric Gram Negative Facultative Anaerobe Bacilli in Aerobic versus Anaerobic Conditions

Science.gov (United States)

Amachawadi, Raghavendra G.; Renter, David G.; Volkova, Victoriya V.

2016-01-01

Antimicrobial treatments result in the host’s enteric bacteria being exposed to the antimicrobials. Pharmacodynamic models can describe how this exposure affects the enteric bacteria and their antimicrobial resistance. The models utilize measurements of bacterial antimicrobial susceptibility traditionally obtained in vitro in aerobic conditions. However, in vivo enteric bacteria are exposed to antimicrobials in anaerobic conditions of the lower intestine. Some of enteric bacteria of food animals are potential foodborne pathogens, e.g., Gram-negative bacilli Escherichia coli and Salmonella enterica. These are facultative anaerobes; their physiology and growth rates change in anaerobic conditions. We hypothesized that their antimicrobial susceptibility also changes, and evaluated differences in the susceptibility in aerobic vs. anaerobic conditions of generic E. coli and Salmonella enterica of diverse serovars isolated from cattle feces. Susceptibility of an isolate was evaluated as its minimum inhibitory concentration (MIC) measured by E-Test® following 24 hours of adaptation to the conditions on Mueller-Hinton agar, and on a more complex tryptic soy agar with 5% sheep blood (BAP) media. We considered all major antimicrobial drug classes used in the U.S. to treat cattle: β-lactams (specifically, ampicillin and ceftriaxone E-Test®), aminoglycosides (gentamicin and kanamycin), fluoroquinolones (enrofloxacin), classical macrolides (erythromycin), azalides (azithromycin), sulfanomides (sulfamethoxazole/trimethoprim), and tetracyclines (tetracycline). Statistical analyses were conducted for the isolates (n≥30) interpreted as susceptible to the antimicrobials based on the clinical breakpoint interpretation for human infection. Bacterial susceptibility to every antimicrobial tested was statistically significantly different in anaerobic vs. aerobic conditions on both media, except for no difference in susceptibility to ceftriaxone on BAP agar. A satellite experiment

First report of environmental isolation of Cryptococcus neoformans and other fungi from pigeon droppings in Makkah, Saudi Arabia and in vitro susceptibility testing

Directory of Open Access Journals (Sweden)

Hussein Hasan Abulreesh

2015-08-01

Full Text Available Objective: To verify the occurrence of Cryptococcus neoformans (C. neoformans and other fungi in samples of pigeon droppings collected from Makkah city, Saudi Arabia. Methods: One hundred and twelve withered pigeon dropping samples were collected from 12 different districts. Using the dilution plate technique, samples were cultured on Sabouraud dextrose agar and esculin agar. Colonies were examined microscopically and C. neoformans identification is confirmed by India ink preparation, observation of urease activity and brown pigmentation on esculin medium. Susceptibility patterns of five yeast species and four molds against five antifungal drugs were tested using agar disk diffusion method. Results: C. neoformans was recovered from 38 samples (34%. Na'aman valley was recorded to be the highest contaminated site (66.7% with C. neoformans, while the samples collected from Al Awaly district were considered as the lowest contaminated samples (6.7%. Also, twenty species related to sixteen genera of fungi other than C. neoformans were recovered from which, three yeast genera were recorded. The antifungal susceptibility testing showed that the nine tested fungal species were sensitive to Mycosat, while Fungican exerted inhibition zones of four species only. C. neoformans was moderately sensitive towards all tested compounds but it can resist Flucoral where no inhibition zone could be detected. Conclusions: Our results are considered to be the first report on the environmental prevalence of C. neoformans in pigeon feces in Makkah, Saudi Arabia. The data indicated that pigeon droppings can be considered as a potential source of this basidiomycetous yeast in addition to other fungal species in this region.

Antifungal susceptibility testing of Candida species isolated from the immunocompromised patients admitted to ten university hospitals in Iran: comparison of colonizing and infecting isolates

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Parisa Badiee

2017-11-01

Full Text Available Abstract Background Antifungal susceptibility testing is a subject of interest in the field of medical mycology. The aim of the present study were the distributions and antifungal susceptibility patterns of various Candida species isolated from colonized and infected immunocompromised patients admitted to ten university hospitals in Iran. Methods In totally, 846 Candida species were isolated from more than 4000 clinical samples and identified by the API 20 C AUX system. Antifungal susceptibility testing was performed by broth microdilution method according to CLSI. Results The most frequent Candida species isolated from all patients was Candida albicans (510/846. The epidemiological cutoff value and percentage of wild-type species for amphotericin B and fluconazole in Candida albicans, Candida tropicalis, Candida glabrata and Candida krusei were 0.5 μg/ml (95% and 4 μg/ml (96%; 1 μg/ml (95% and 8 μg/ml (95%; 0.5 μg/ml (99% and 19 μg/ml (98%; and 4 μg/ml (95% and 64 μg/ml (95%, respectively. The MIC90 and epidemiological cutoff values to posaconazole in Candida krusei were 0.5 μg/ml. There were significant differences between infecting and colonizing isolates of Candida tropicalis in MIC 90 values of amphotericin B, and isolates of Candida glabrata in values of amphotericin B, caspofungin, and voriconazole (P < 0.05. Conclusions Our findings suggest that the susceptibility patterns of Candida species (colonizing and infecting isolates in immunocompromised patients are not the same and acquired resistance was seen in some species.

Ethical, legal and social implications of prenatal and preimplantation genetic testing for cancer susceptibility.

Science.gov (United States)

Wang, C-W; Hui, E C

2009-01-01

With the progress in cancer genetics and assisted reproductive technologies, it is now possible for cancer gene mutation carriers not only to reduce cancer mortality through the targeting of surveillance and preventive therapies, but also to avoid the birth of at-risk babies through the choice of different means of reproduction. Thus, the incidence of hereditary cancer syndromes may be decreased in the future. The integration of cancer genetic testing and assisted reproductive technologies raises certain ethical, legal and social issues beyond either genetic testing or assisted reproductive technology itself. In this paper, the reproductive decisions/choices of at-risk young couples and the ethical, legal and social concerns of prenatal genetic testing and preimplantation genetic diagnosis for susceptibility to hereditary cancer syndromes are discussed. Specifically, three ethical principles related to the integration of cancer genetic testing and assisted reproductive technologies, i.e. informed choice, beneficence to children and social justice, and their implications for the responsible translation of these medical techniques into common practice of preventive medicine are highlighted.

Genetic testing of newborns for type 1 diabetes susceptibility: a prospective cohort study on effects on maternal mental health

Directory of Open Access Journals (Sweden)

Magnus Per

2010-07-01

Full Text Available Abstract Background Concerns about the general psychological impact of genetic testing have been raised. In the Environmental Triggers of Type 1 Diabetes (MIDIA study, genetic testing was performed for HLA-conferred type 1 diabetes susceptibility among Norwegian newborns. The present study assessed whether mothers of children who test positively suffer from poorer mental health and well-being after receiving genetic risk information about their children. Methods The study was based on questionnaire data from the Norwegian Mother and Child Cohort (MoBa study conducted by the Norwegian Institute of Public Health. Many of the mothers in the MoBa study also took part in the MIDIA study, in which their newborn children were tested for HLA-conferred genetic susceptibility for type 1 diabetes. We used MoBa questionnaire data from the 30th week of pregnancy (baseline and 6 months post-partum (3-3.5 months after disclosure of test results. We measured maternal symptoms of anxiety and depression (SCL-8, maternal self-esteem (RSES, and satisfaction with life (SWLS. The mothers also reported whether they were seriously worried about their child 6 months post-partum. We compared questionnaire data from mothers who had received information about having a newborn with high genetic risk for type 1 diabetes (N = 166 with data from mothers who were informed that their baby did not have a high-risk genotype (N = 7224. The association between genetic risk information and maternal mental health was analysed using multiple linear regression analysis, controlling for baseline mental health scores. Results Information on genetic risk in newborns was found to have no significant impact on maternal symptoms of anxiety and depression (p = 0.9, self-esteem (p = 0.2, satisfaction with life (p = 0.2, or serious worry about their child (OR = 0.98, 95% CI 0.64-1.48. Mental health before birth was strongly associated with mental health after birth. In addition, an increased

The BTNL2 G16071A gene polymorphism increases granulomatous disease susceptibility

Science.gov (United States)

Tong, Xiang; Ma, Yao; Niu, Xundong; Yan, Zhipeng; Liu, Sitong; Peng, Bo; Peng, Shifeng; Fan, Hong

2016-01-01

Abstract Objective: The butyrophilin-like 2 (BTNL2) G16071A gene polymorphism has been implicated in the susceptibility to granulomatous diseases, but the results were inconclusive. The objective of the current study was to precisely explore the relationship between BTNL2 G16071A gene polymorphism and granulomatous disease susceptibility by the meta-analysis including false-positive report probability (FPRP) test. Methods: A systematic literature search in the PubMed, Embase, and Wanfang databases, China National Knowledge Internet, and commercial Internet search engines was conducted to identify studies published up to April 1, 2016. The odds ratio (OR) with 95% confidence interval (CI) was used to assess the effect size. Statistical analysis was conducted using the STATA 12.0 software and FPRP test sheet. Results: In total, all 4324 cases and 4386 controls from 14 eligible studies were included in the current meta-analysis. By the overall meta-analysis, we found a significant association between BTNL2 G16071A gene polymorphism and granulomatous disease susceptibility (A vs G: OR = 1.25, 95% CI = 1.07–1.45, P = 0.005). The meta-regression analyses showed that a large proportion of the between-study heterogeneity was significantly attributed to the ethnicity (A vs G, P = 0.013) and the types of granulomatous diseases (A vs G, P = 0.002). By the subgroup meta-analysis, the BTNL2 G16071A gene polymorphism was associated with granulomatous disease susceptibility in Caucasians (A vs G: OR = 1.37, 95% CI = 1.18–1.58, P susceptibility (A vs G: OR = 1.52, 95% CI = 1.39–1.66, P susceptibility (A vs G, FPRP susceptibility among Caucasians (A vs G, FPRP susceptibility, especially increasing the sarcoidosis susceptibility. In addition, the polymorphism may be greatly associated with likelihood of granulomatous diseases among Caucasians. PMID:27472712

Genome-wide high-density SNP linkage search for glioma susceptibility loci: results from the Gliogene Consortium

DEFF Research Database (Denmark)

Shete, Sanjay; Lau, Ching C; Houlston, Richard S

2011-01-01

.S. families and obtained a maximum NPL score of 1.26 (P = 0.008) and the Z-score of 1.47 (P = 0.035). Accounting for the genetic heterogeneity using the ordered subset analysis approach, the combined analyses of 75 families resulted in a maximum NPL score of 3.81 (P = 0.00001). The genomic regions we have...... implicated in this study may offer novel insights into glioma susceptibility, focusing future work to identify genes that cause familial glioma.......-fold increased risk of glioma, the search for susceptibility loci in familial forms of the disease has been challenging because the disease is relatively rare, fatal, and heterogeneous, making it difficult to collect sufficient biosamples from families for statistical power. To address this challenge...

Serological Susceptibility to Varicella Among U.S. Immigration and Customs Enforcement Detainees.

Science.gov (United States)

Varan, Aiden K; Lederman, Edith R; Stous, Shanon S; Elson, Diana; Freiman, Jennifer L; Marin, Mona; Lopez, Adriana S; Stauffer, William M; Joseph, Rachael H; Waterman, Stephen H

2018-01-01

U.S. Immigration and Customs Enforcement (ICE) is responsible for detaining unauthorized aliens during immigration proceedings. During 2014 to 2015, adult ICE detainees at a California facility were invited to complete a survey concerning self-reported varicella history and risk factors. Participants underwent serological testing for varicella-zoster virus (VZV) IgG; susceptible individuals were offered varicella vaccination. Among 400 detainees with available serology results, 48 (12%) were susceptible to varicella. Self-reported varicella history was negatively associated with susceptibility (adjusted odds ratio = 0.16; 95% confidence interval [0.07, 0.35]). Among 196 detainees reporting a positive history, 95% had VZV IgG levels suggestive of varicella immunity. Among 44 susceptible detainees offered vaccination, 86% accepted. Given relatively high varicella susceptibility, targeted screening and vaccination among ICE detainees lacking a positive history might reduce varicella transmission risks.

CISH and Susceptibility to Infectious Diseases

Science.gov (United States)

Khor, Chiea C.; Vannberg, Fredrik O.; Chapman, Stephen J.; Guo, Haiyan; Wong, Sunny H.; Walley, Andrew J.; Vukcevic, Damjan; Rautanen, Anna; Mills, Tara C.; Chang, Kwok-Chiu; Kam, Kai-Man; Crampin, Amelia C.; Ngwira, Bagrey; Leung, Chi-Chiu; Tam, Cheuk-Ming; Chan, Chiu-Yeung; Sung, Joseph J.Y.; Yew, Wing-Wai; Toh, Kai-Yee; Tay, Stacey K.H.; Kwiatkowski, Dominic; Lienhardt, Christian; Hien, Tran-Tinh; Day, Nicholas P.; Peshu, Nobert; Marsh, Kevin; Maitland, Kathryn; Scott, J. Anthony; Williams, Thomas N.; Berkley, James A.; Floyd, Sian; Tang, Nelson L.S.; Fine, Paul E.M.; Goh, Denise L.M.; Hill, Adrian V.S.

2013-01-01

Background The interleukin-2 (IL2)-mediated immune response is critical for host defence against infectious pathogens. CISH, a suppressor of cytokine signalling, controls IL2 signalling. Methods We tested for association between CISH polymorphisms and susceptibility to major infectious diseases (bacteremia, tuberculosis and severe malaria) in 8402 persons from the Gambia, Hong Kong, Kenya, Malawi, and Vietnam using a case-control design. We have previously tested twenty other immune-related genes in one or more of these sample collections. Results We observed associations between variant alleles of multiple CISH polymorphisms and increased susceptibility to each infectious disease in each of the study populations. When all five SNPs (CISH −639, −292, −163, +1320 and +3415) within the CISH-associated locus were considered together in a multi-SNP score, we found substantial support for an effect of CISH genetic variants on susceptibility to bacteremia, malaria, and tuberculosis (overall P=3.8 × 10−11) with CISH −292 being “responsible” for the majority of the association signal (P=4.58×10−7). Peripheral blood mononuclear cells of adult volunteers carrying the CISH −292 variant showed a muted response to IL2 stimulation — in the form of 25-40% less CISH — when compared with “control” cells lacking the −292 variant. Conclusions Variants of CISH are associated with susceptibility to diseases caused by diverse infectious pathogens, suggesting that negative regulators of cytokine signalling may play a major role in immunity against various infectious diseases. The overall risk of having one of these infectious diseases was found to be increased by at least 18 percent in individuals carrying the variant CISH alleles. PMID:20484391

Differences in the antimicrobial susceptibility profiles of Moraxella bovis, M. bovoculi and M. ovis

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Grazieli Maboni

2015-06-01

Full Text Available The aim of this study was to determine the differences in the antimicrobial susceptibility profiles of Moraxella bovis, M. bovoculi and M. ovis. Thirty-two strains of Moraxella spp. isolated from cattle and sheep with infectious keratoconjunctivitis were tested via broth microdilution method to determine their susceptibility to ampicillin, cefoperazone, ceftiofur, cloxacillin, enrofloxacin, florfenicol, gentamicin, neomycin, oxytetracycline and penicillin. The results demonstrated that Moraxella spp. strains could be considered sensitive for most of the antimicrobials tested in this study, but differences between the antimicrobial susceptibility profiles of these three Moraxella species were found. M. bovis might differ from other species due to the higher MIC and MBC values it presented.

Differences in the antimicrobial susceptibility profiles of Moraxella bovis, M. bovoculi and M. ovis

Science.gov (United States)

Maboni, Grazieli; Gressler, Leticia T.; Espindola, Julia P.; Schwab, Marcelo; Tasca, Caiane; Potter, Luciana; de Vargas, Agueda Castagna

2015-01-01

The aim of this study was to determine the differences in the antimicrobial susceptibility profiles of Moraxella bovis, M. bovoculi and M. ovis. Thirty-two strains of Moraxella spp. isolated from cattle and sheep with infectious keratoconjunctivitis were tested via broth microdilution method to determine their susceptibility to ampicillin, cefoperazone, ceftiofur, cloxacillin, enrofloxacin, florfenicol, gentamicin, neomycin, oxytetracycline and penicillin. The results demonstrated that Moraxella spp. strains could be considered sensitive for most of the antimicrobials tested in this study, but differences between the antimicrobial susceptibility profiles of these three Moraxella species were found. M. bovis might differ from other species due to the higher MIC and MBC values it presented. PMID:26273272

Quantitative measurements of brain iron deposition in cirrhotic patients using susceptibility mapping.

Science.gov (United States)

Xia, Shuang; Zheng, Gang; Shen, Wen; Liu, Saifeng; Zhang, Long Jiang; Haacke, E Mark; Lu, Guang Ming

2015-03-01

Susceptibility-weighted imaging (SWI) has been used to detect micro-bleeds and iron deposits in the brain. However, no reports have been published on the application of SWI in studying iron changes in the brain of cirrhotic patients. To compare the susceptibility of different brain structures in cirrhotic patients with that in healthy controls and to evaluate susceptibility as a potential biomarker and correlate the measured susceptibility and cadaveric brain iron concentration for a variety of brain structures. Forty-three cirrhotic patients (27 men, 16 women; mean age, 50 ± 9 years) and 34 age- and sex-matched healthy controls (22 men, 12 women; mean age, 47 ± 7 years) were included in this retrospective study. Susceptibility was measured in the frontal white matter, basal ganglia, midbrain, and dentate nucleus and compared with results gathered from two postmortem brain studies. Correlation between susceptibility and clinical biomarkers and neuropsychiatric tests scores was calculated. In cirrhotic patients, the susceptibility of left frontal white matter, bilateral caudate head, and right substantia nigra was higher than that in healthy controls (P brain study (r = 0.835, P = 0.01) in eight deep grey matter structures and another in five brain structures (r = 0.900, P = 0.03). The susceptibility of right caudate head (r = 0.402) and left caudate head (r = 0.408) correlated with neuropsychological test scores (both P brain regions appears to reflect neurocognitive changes. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Health Psychological Constructs as Predictors of Doping Susceptibility in Adolescent Athletes

Science.gov (United States)

Blank, Cornelia; Schobersberger, Wolfgang; Leichtfried, Veronika; Duschek, Stefan

2016-01-01

Background Doping is a highly relevant problem in sport, even in adolescent athletes. Knowledge of the psychological factors that influence doping susceptibility in young elite athletes remains sparse. Objectives This study investigated the predictive potential of different health-psychological constructs and well-being on doping susceptibility. The main hypotheses to be tested were positive associations of fear of failure, external locus of control, and ego-oriented goal orientation as well as negative associations of confidence of success, task orientation, internal locus of control, and performance motivation with doping susceptibility. Low levels of well-being are furthermore expected to be associated with doping susceptibility. Methods Within this cross-sectional study, 1,265 Austrian junior athletes aged between 14 and 19 years responded to a paper-pencil questionnaire. Results Performance motivation was a negative, while depressive mood, self-esteem, fear of failure and ego-oriented goal orientation were positive predictors of doping susceptibility. In addition, participants who were offered performance enhancing substances in the past were particularly susceptible to doping. Conclusions The study corroborates the predictive value of classical psychological constructs in doping research, initially analyzed in view of adult athletes, also for adolescents’ doping susceptibility. PMID:28144408

Characterization of Salmonella Typhimurium isolates from domestically acquired infections in Finland by phage typing, antimicrobial susceptibility testing, PFGE and MLVA.

Science.gov (United States)

Lienemann, Taru; Kyyhkynen, Aino; Halkilahti, Jani; Haukka, Kaisa; Siitonen, Anja

2015-07-02

Salmonella enterica spp. enterica serotype Typhimurium (STM) is the most common agent of domestically acquired salmonellosis in Finland. Subtyping methods which allow the characterization of STM are essential for effective laboratory-based STM surveillance and for recognition of outbreaks. This study describes the diversity of Finnish STM isolates using phage typing, antimicrobial susceptible testing, pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem repeat analysis (MLVA), and compares the discriminatory power and the concordance of these methods. A total of 375 sporadic STM isolates were analysed. The isolates were divided into 31 definite phage (DT) types, dominated by DT1 (47 % of the isolates), U277 (9 % of the isolates) and DT104 (8 % of the isolates). Of all the isolates, 62 % were susceptible to all the 12 antimicrobials tested and 11 % were multidrug resistant. Subtyping resulted in 83 different XbaI-PFGE profiles and 111 MLVA types. The three most common XbaI-PFGE profiles (STYM1, STYM7 and STYM8) and one MLVA profile with three single locus variants accounted for 56 % and 49 % of the STM isolates, respectively. The studied isolates showed a genetic similarity of more than 70 % by XbaI-PFGE. In MLVA, 71 % of the isolates lacked STTR6 and 77 % missed STTR10p loci. Nevertheless, the calculated Simpson's diversity index for XbaI-PFGE was 0.829 (95 % CI 0.792-0.865) and for MLVA 0.867 (95 % CI 0.835-0.898). However, the discriminatory power of the 5-loci MLVA varied among the phage types. The highest concordance of the results was found between XbaI-PFGE and phage typing (adjusted Wallace coefficient was 0.833 and adjusted Rand coefficient was 0.627). In general, the calculated discriminatory power was higher for genotyping methods (MLVA and XbaI-PFGE) than for phenotyping methods (phage typing). Overall, comparable diversity indices were calculated for PFGE and MLVA (both DI > 0.8). However, MLVA was phage type dependent

A 96-well-plate-based optical method for the quantitative and qualitative evaluation of Pseudomonas aeruginosa biofilm formation and its application to susceptibility testing.

Science.gov (United States)

Müsken, Mathias; Di Fiore, Stefano; Römling, Ute; Häussler, Susanne

2010-08-01

A major reason for bacterial persistence during chronic infections is the survival of bacteria within biofilm structures, which protect cells from environmental stresses, host immune responses and antimicrobial therapy. Thus, there is concern that laboratory methods developed to measure the antibiotic susceptibility of planktonic bacteria may not be relevant to chronic biofilm infections, and it has been suggested that alternative methods should test antibiotic susceptibility within a biofilm. In this paper, we describe a fast and reliable protocol for using 96-well microtiter plates for the formation of Pseudomonas aeruginosa biofilms; the method is easily adaptable for antimicrobial susceptibility testing. This method is based on bacterial viability staining in combination with automated confocal laser scanning microscopy. The procedure simplifies qualitative and quantitative evaluation of biofilms and has proven to be effective for standardized determination of antibiotic efficiency on P. aeruginosa biofilms. The protocol can be performed within approximately 60 h.

Incidence and Antibiotic Susceptibility Pattern of Bacterial Isolates ...

African Journals Online (AJOL)

In vitro antibiotic susceptibility tests showed that Pseudomonas aeruginosa was susceptible to ceftazidime, ciprofloxacin and gentamicin while the enteric bacteria were generally more resistant to ceftazidime, gentamicin and ciprofloxacin. Conclusion: The findings show that there is a high rate of wound infection in Kano, ...

Formation of Linear Gradient of Antibiotics on Microfluidic Chips for High-throughput Antibiotic Susceptibility Testing

Science.gov (United States)

Kim, Seunggyu; Lee, Seokhun; Jeon, Jessie S.

2017-11-01

To determine the most effective antimicrobial treatments of infectious pathogen, high-throughput antibiotic susceptibility test (AST) is critically required. However, the conventional AST requires at least 16 hours to reach the minimum observable population. Therefore, we developed a microfluidic system that allows maintenance of linear antibiotic concentration and measurement of local bacterial density. Based on the Stokes-Einstein equation, the flow rate in the microchannel was optimized so that linearization was achieved within 10 minutes, taking into account the diffusion coefficient of each antibiotic in the agar gel. As a result, the minimum inhibitory concentration (MIC) of each antibiotic against P. aeruginosa could be immediately determined 6 hours after treatment of the linear antibiotic concentration. In conclusion, our system proved the efficacy of a high-throughput AST platform through MIC comparison with Clinical and Laboratory Standards Institute (CLSI) range of antibiotics. This work was supported by the Climate Change Research Hub (Grant No. N11170060) of the KAIST and by the Brain Korea 21 Plus project.

Antifungal susceptibility and phylogeny of opportunistic members of the order mucorales.

Science.gov (United States)

Vitale, Roxana G; de Hoog, G Sybren; Schwarz, Patrick; Dannaoui, Eric; Deng, Shuwen; Machouart, Marie; Voigt, Kerstin; van de Sande, Wendy W J; Dolatabadi, Somayeh; Meis, Jacques F; Walther, Grit

2012-01-01

The in vitro susceptibilities of 66 molecularly identified strains of the Mucorales to eight antifungals (amphotericin B, terbinafine, itraconazole, posaconazole, voriconazole, caspofungin, micafungin, and 5-fluorocytosine) were tested. Molecular phylogeny was reconstructed based on the nuclear ribosomal large subunit to reveal taxon-specific susceptibility profiles. The impressive phylogenetic diversity of the Mucorales was reflected in susceptibilities differing at family, genus, and species levels. Amphotericin B was the most active drug, though somewhat less against Rhizopus and Cunninghamella species. Posaconazole was the second most effective antifungal agent but showed reduced activity in Mucor and Cunninghamella strains, while voriconazole lacked in vitro activity for most strains. Genera attributed to the Mucoraceae exhibited a wide range of MICs for posaconazole, itraconazole, and terbinafine and included resistant strains. Cunninghamella also comprised strains resistant to all azoles tested but was fully susceptible to terbinafine. In contrast, the Lichtheimiaceae completely lacked strains with reduced susceptibility for these antifungals. Syncephalastrum species exhibited susceptibility profiles similar to those of the Lichtheimiaceae. Mucor species were more resistant to azoles than Rhizopus species. Species-specific responses were obtained for terbinafine where only Rhizopus arrhizus and Mucor circinelloides were resistant. Complete or vast resistance was observed for 5-fluorocytosine, caspofungin, and micafungin. Intraspecific variability of in vitro susceptibility was found in all genera tested but was especially high in Mucor and Rhizopus for azoles and terbinafine. Accurate molecular identification of etiologic agents is compulsory to predict therapy outcome. For species of critical genera such as Mucor and Rhizopus, exhibiting high intraspecific variation, susceptibility testing before the onset of therapy is recommended.

Drug susceptibility testing in microaerophilic parasites: Cysteine strongly affects the effectivities of metronidazole and auranofin, a novel and promising antimicrobial

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David Leitsch

2017-12-01

Full Text Available The microaerophilic parasites Entamoeba histolytica, Trichomonas vaginalis, and Giardia lamblia annually cause hundreds of millions of human infections which are treated with antiparasitic drugs. Metronidazole is the most often prescribed drug but also other drugs are in use, and novel drugs with improved characteristics are constantly being developed. One of these novel drugs is auranofin, originally an antirheumatic which has been relabelled for the treatment of parasitic infections. Drug effectivity is arguably the most important criterion for its applicability and is commonly assessed in susceptibility assays using in vitro cultures of a given pathogen. However, drug susceptibility assays can be strongly affected by certain compounds in the growth media. In the case of microaerophilic parasites, cysteine which is added in large amounts as an antioxidant is an obvious candidate because it is highly reactive and known to modulate the toxicity of metronidazole in several microaerophilic parasites.In this study, it was attempted to reduce cysteine concentrations as far as possible without affecting parasite viability by performing drug susceptibility assays under strictly anaerobic conditions in an anaerobic cabinet. Indeed, T. vaginalis and E. histolytica could be grown without any cysteine added and the cysteine concentration necessary to maintain G. lamblia could be reduced to 20%. Susceptibilities to metronidazole were found to be clearly reduced in the presence of cysteine. With auranofin the protective effect of cysteine was extreme, providing protection to concentrations up to 100-fold higher as observed in the absence of cysteine. With three other drugs tested, albendazole, furazolidone and nitazoxanide, all in use against G. lamblia, the effect of cysteine was less pronounced. Oxygen was found to have a less marked impact on metronidazole and auranofin than cysteine but bovine bile which is standardly used in growth media for G

21 CFR 866.1645 - Fully automated short-term incubation cycle antimicrobial susceptibility system.

Science.gov (United States)

2010-04-01

..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES... determining in vitro susceptibility of bacterial pathogens isolated from clinical specimens. Test results...

Differential Susceptibility to Social Contexts : Putting "For Better and For Worse" to the test

NARCIS (Netherlands)

Slagt, M.I.

2017-01-01

The differential susceptibility model asserts that individuals vary in their general susceptibility to environmental influences.Crucially, the very children that are disproportionately vulnerable to harsh and low-quality parenting, may benefit disproportionately from supportive and high-quality

Effect of point-of-care susceptibility testing in general practice on appropriate prescription of antibiotics for patients with uncomplicated urinary tract infection

DEFF Research Database (Denmark)

Holm, Anne; Cordoba, Gloria; Møller Sørensen, Tina

2017-01-01

OBJECTIVES: To investigate the effect of adding point-of-care (POC) susceptibility testing to POC culture on appropriate use of antibiotics as well as clinical and microbiological cure for patients with suspected uncomplicated urinary tract infection (UTI) in general practice. DESIGN: Open......, individually randomised controlled trial. SETTING: General practice. PARTICIPANTS: Women with suspected uncomplicated UTI, including elderly patients above 65, patients with recurrent UTI and patients with diabetes. The sample size calculation predicted 600 patients were needed. INTERVENTIONS: Flexicult SSI......-Urinary Kit was used for POC culture and susceptibility testing and ID Flexicult was used for POC culture only. MAIN OUTCOME MEASURES: Primary outcome: appropriate antibiotic prescribing on the day after consultation defined as either (1) patient with UTI: to prescribe a first-line antibiotic to which...

Xenopsylla cheopis (Siphonaptera: Pulicidae susceptibility to Deltamethrin in Madagascar.

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Sebastien Boyer

Full Text Available The incidence of bubonic plague in Madagascar is high. This study reports the susceptibility of 32 different populations of a vector, the flea Xenopsylla cheopis (Siphonaptera: Pulicidae, to the insecticide Deltamethrin. Despite the use of Deltamethrin against fleas, plague epidemics have re-emerged in Madagascar. The majority of the study sites were located in the Malagasy highlands where most plague cases have occurred over the last 10 years. X. cheopis fleas were tested for susceptibility to Deltamethrin (0.05%: only two populations were susceptible to Deltamethrin, four populations were tolerant and 26 populations were resistant. KD50 (50% Knock-Down and KD90 (90% Knock-Down times were determined, and differed substantially from 9.4 to 592.4 minutes for KD50 and 10.4 min to 854.3 minutes for KD90. Susceptibility was correlated with latitude, but not with longitude, history of insecticide use nor date of sampling. Combined with the number of bubonic plague cases, our results suggest that an immediate switch to an insecticide other than Deltamethrin is required for plague vector control in Madagascar.

Optimization and evaluation of Flexicult(®) Vet for detection, identification and antimicrobial susceptibility testing of bacterial uropathogens in small animal veterinary practice

DEFF Research Database (Denmark)

Guardabassi, Luca; Hedberg, Sandra; Jessen, Lisbeth Rem

2015-01-01

BACKGROUND: Urinary tract infection (UTI) is a common reason for antimicrobial prescription in dogs and cats. The objective of this study was to optimize and evaluate a culture-based point-of-care test for detection, identification and antimicrobial susceptibility testing of bacterial uro......-pathogens in veterinary practice. METHODS: Seventy-two urine samples from dogs and cats with suspected UTI presenting to seven veterinary facilities were used by clinical staff and an investigator to estimate sensitivity and specificity of Flexicult Vet A compared to laboratory reference standards for culture...... B (commercial name Flexicult(®) Vet) is a time- and cost-effective point-of-care test to guide antimicrobial choice and facilitate implementation of antimicrobial use guidelines for treatment of UTIs in small animals, provided that clinical staff is adequately trained to interpret the results...

Antimicrobial susceptibility of porcine brachyspira hyodysenteriae isolates from Switzerland

OpenAIRE

Kirchgässner, Constanze

2016-01-01

The anaerobic spirochaete Brachyspira (B.) hyodysenteriae is the causative agent of swine dysentery (SD), a severe mucohaemorrhagic diarrheal disease in pigs worldwide. Currently, no data for antimicrobial susceptibility of B. hyodysenteriae from Switzerland are available and though antimicrobial treatment is the main therapy, no standardised methods for antimicrobial susceptibility testing are established. Therefore, a broth microdilution test was performed for 30 Swiss porcine field isolate...

Stress corrosion cracking susceptibilities of various stainless steels in high temperature water

International Nuclear Information System (INIS)

Shoji, Saburo; Ohnaka, Noriyuki; Kikuchi, Eiji; Minato, Akira; Tanno, Kazuo.

1980-01-01

The intergranular stress corrosion cracking (IGSCC) behaviors of several austenitic stainless steels in high temperature water were evaluated using three types of SCC tests, i.e., single U-bend test in chloride containing water, uniaxial constant load and constant extension rate tests (CERT) in pure water. The steels used were SUS 304, 304L, 316, 316L, 321 and 347 and several heats of them to examine heat to heat variations. The three test methods gave the same relative ranking of the steels. The CERT is the most sensitive method to detect the relative IGSCC susceptibilities. The CERT result for relative ranking from poor to good is: SUS 304 - 0.07% C, 304 - 0.06% C, 304L - 0.028% C, 316 - 0.07% C. The IGSCC susceptibilities of SUS 304L - 0.020% C, 316L - 0.023% C, 321 and 347 were not detected. These test results suggest that the use of the low carbon, molybdenum bearing, or stabilized austenitic stainless steel is beneficial for eliminating the IGSCC problem in boiling water reactor environment. (author)

CCTF CORE I test results

International Nuclear Information System (INIS)

Murao, Yoshio; Sudoh, Takashi; Akimoto, Hajime; Iguchi, Tadashi; Sugimoto, Jun; Fujiki, Kazuo; Hirano, Kenmei

1982-07-01

This report presents the results of the following CCTF CORE I tests conducted in FY. 1980. (1) Multi-dimensional effect test, (2) Evaluation model test, (3) FLECHT coupling test. On the first test, one-dimensional treatment of the core thermohydrodynamics was discussed. On the second and third tests, the test results were compared with the results calculated by the evaluation model codes and the results of the corresponding FLECHT-SET test (Run 2714B), respectively. The work was performed under contracts with the Atomic Energy Bureau of Science and Technology Agency of Japan. (author)

A case of Candida famata sepsis in a very low birth weight infant successfully treated with fluconazole following antifungal susceptibility testing

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Shilpee Raturi

2015-01-01

This case report highlights the growing number of cases arising due to nonalbicans Candida infections in the neonatal intensive care units and the usefulness of antifungal susceptibility testing in deciding optimal antifungal therapy and preventing the emergence of drug resistance.

[Epidemiological characteristics of typhoid fever and antibiotic susceptibility testing of Salmonella Typhi isolates in Guangxi, 1994-2013].

Science.gov (United States)

Wang, Mingliu; Kan, Biao; Yang, Jin; Lin, Mei; Yan, Meiying; Zeng, Jun; Quan, Yi; Liao, Hezhuang; Zhou, Lingyun; Jiang, Zhenling; Huang, Dehui

2014-08-01

Through analyzing the typhoid epidemics and to determine and monitor regional resistance characteristics of the shift of drug resistant profile on Salmonella (S.) Typhi, to understand the related epidemiological characteristics of typhoid fever and to provide evidence for the development of strategies, in Guangxi. Data of typhoid fever from surveillance and reporting system between 1994 to 2013 was collected and statistically analyzed epidemiologically. The susceptibility of 475 S. Typhi isolates from patients on ten antibiotics was tested by broth micro-dilution method and minimum inhibition concentration was obtained and interpreted based on the CLSI standard. From 1994 to 2013, a total of 57 928 cases of typhoid fever were reported in Guangxi province with an annual incidence of 6.29/100 000 and mortality as 0.03%. The higher incidence was observed in the population under 20 years of age. There was no significant difference on incidence between male and female, but farmers and students were among the hardest hit groups. More cases were seen from the northern part of the province. Cases appeared all year round with the peak from May to October. A total of 13 major outbreaks during 2001 to 2013 were reported and the main transmission route was water-borne. All the strains were sensitive to third generation cephalosporins cefotaxime and fluoroquinolones norfloxacin. The susceptibility rates to tetracycline, chloramphenicol, ampicillin and gentamicin was around 98% but relative lower susceptible rate to ciprofloxacin was seen as 89.89% . The lowest susceptibility was found for streptomycin and sulfamethoxazole agents, with the rates as 67.73% and 65.89% , respectively. One strain was found to have been resistant to ciprofloxacin and another 47 isolates with reduced susceptibility to ciprofloxacin. Twenty eight isolates were found to be resistant to multiple antibiotics and one displayed ampicillin, chloramphenicol, streptomycin, sulfamethoxazole tetracycline and

In vitro susceptibility of Candida spp. to fluconazole, itraconazole and voriconazole and the correlation between triazoles susceptibility: Results from a five-year study.

Science.gov (United States)

Lei, J; Xu, J; Wang, T

2018-06-01

Candida spp. is a common cause of invasive fungal disease. The aim of this study was to examine the susceptibility of Candida spp. to fluconazole, itraconazole and voriconazole and explore the correlation between triazoles susceptibility. The antifungal susceptibility in the present study was measured by ATB Fungus 3 method, and the potential relationship was examined by obtaining the correlation of measured minimal inhibitory concentrations (MICs) of Candida spp. isolates. A total of 2099 clinical isolates of Candida spp. from 1441 patients were analyzed. The organisms included 1435 isolates of Candida albicans, 207 isolates of Candida glabrata, 65 isolates of Candida parapsilosis, 31 isolates of Candida krusei, 268 isolates of Candida tropicalis. Voriconazole and itraconazole were more active than fluconazole and against Candida spp. in vitro. The fluconazole, itraconazole and voriconazole MIC 90 (MIC for 90% of the isolates) for all Candida spp. isolates was 4mg/L, 1mg/L and 0.25mg/L, respectively. There was a moderate correlation between the fluconazole MIC s for Candida spp. isolates and this for voriconazole (R 2 =0.475; P<0.01) and itraconazole (R 2 =0.431; P<0.01). Voriconazole MICs for the Candida spp. isolates also correlated with those for itraconazole (R 2 =0.401; P<0.01). These observations suggest that the in vitro susceptibility of Candida spp. to fluconazole, itraconazole and voriconazole exhibits a moderate correlation. Published by Elsevier Masson SAS.

[Consensus for antimicrobial susceptibility testing for Enterobacteriaceae. Subcommittee on Antimicrobials, SADEBAC (Argentinian Society of Clinical Bacteriology), Argentinian Association of Microbiology].

Science.gov (United States)

Famiglietti, A; Quinteros, M; Vázquez, M; Marín, M; Nicola, F; Radice, M; Galas, M; Pasterán, F; Bantar, C; Casellas, J M; Kovensky Pupko, J; Couto, E; Goldberg, M; Lopardo, H; Gutkind, G; Soloaga, R

2005-01-01

Taking into account previous recommendations from the National Committee for Clinical Laboratory Standards (NCCLS), the Antimicrobial Committee, Sociedad Argentina de Bacteriología Clínica (SADEBAC), Asociación Argentina de Microbiología (AAM), and the experience from its members and some invited microbiologists, a consensus was obtained for antimicrobial susceptibility testing and interpretation in most frequent enterobacterial species isolated from clinical samples in our region. This document describes the natural antimicrobial resistance of some Enterobacteriaceae family members, including the resistance profiles due to their own chromosomal encoded beta-lactamases. A list of the antimicrobial agents that should be tested, their position on the agar plates, in order to detect the most frequent antimicrobial resistance mechanisms, and considerations on which antimicrobial agents should be reported regarding to the infection site and patient characteristics are included. Also, a description on appropriate phenotypic screening and confirmatory test for detection of prevalent extended spectrum beta-lactamases in our region are presented. Finally, a summary on frequent antimicrobial susceptibility profiles and their probably associated resistance mechanisms, and some infrequent antimicrobial resistance profiles that deserve confirmation are outlined.

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.

Molecular identification and in-vitro antifungal susceptibility testing of Candida species isolated from patients with onychomycosis

Directory of Open Access Journals (Sweden)

Keyvan Pakshir

2015-03-01

Full Text Available Background and Purpose: Candida species are the most opportunistic fungi affecting the nails and resulting in onychomycosis. In this study, we identified and evaluated in-vitro susceptibility of the recovered isolates against fluconazole (FLC, voriconazole (VRC, and clotrimazole (CLT using the Clinical and Laboratory Standards Institute (CLSI M27-A3 document. Materials and Methods: From patients with either clinically or mycologically proven onychomycosis, 97 isolates comprising of seven Candida species were isolated, which were identified by both conventional and molecular techniques such as polymerase chain reaction-restriction fragment length polymorphism. In addition, Candida dubliniensis was confirmed by restriction endonuclease analysis. Antifungal susceptibility of each isolate against the three azoles applied in this study was determined using the CLSI microdilution reference method M27-A3. Results: Candida parapsilosis (C. parapsilosis was the most frequently isolated species (n=44, followed by C. albicans (n=23, C. tropicalis (n=13, C. glabrata (n=7, C. krusei (n=6, C. guilliermondii (n=3, and C. dubliniensis (n=1. All the isolates were susceptible to CLT. VRC had lower minimum inhibitory concentration (MIC values for the isolates compared to FLC. Geometric mean MIC values of VRC, FLC, and CLT for C. parapsilosis isolates were 0.07 µg/ml, 0.8 µg/ml, and 0.35 µg/ml, respectively. Collectively, all species exhibited greater susceptibility to VRC in comparison to C. albicans (P≤0.001. Conclusion: This study showed that non-albicans Candida species were the most common etiologic agents of non-dermatophyte onychomycosis. The major antifungal agents used in clinics to empirically treat yeast onychomycosis are FLC and CLT. Our data suggested that CLT is a better choice for the treatment of Candida onychomycosis, especially in drug resistant cases.

Prevalence and antimicrobial susceptibility of thermophilic Campylobacter in organic and conventional broiler flocks

DEFF Research Database (Denmark)

Heuer, Ole Eske; Pedersen, Karl; Andersen, J.S.

2001-01-01

Aims: To determine the flock prevalence and to estimate the within flock prevalence of Campylobacter in broiler flocks from different rearing systems, and to determine the antimicrobial susceptibility of Campylobacter isolates to selected antimicrobial substances. Methods and Results: One hundred...... and sixty broiler flocks originating from organic, conventional and extensive indoor production farms were investigated for the presence of Campylobacter at the time of slaughter. Campylobacter isolates from a subsample of positive flocks were subjected to susceptibility testing. Campylobacter spp. were...... isolated from 100% of organic broiler flocks, from 36.7% of conventional broiler flocks and from 49.2% of extensive indoor broiler flocks. Six of 62 Campylobacter isolates were resistant to one or more of the antimicrobials tested. Conclusions: These results indicate that the special characteristics...

Dynamic insecticide susceptibility changes in Florida populations of Diaphorina citri (Hemiptera: Psyllidae).

Science.gov (United States)

Tiwari, Siddharth; Killiny, Nabil; Stelinski, Lukasz L

2013-02-01

Five field populations of Diaphorina citri Kuwayama from various regions of Florida were evaluated in 2011 for resistance to commonly used insecticides. Three diagnostic doses (LD50, LD75, and LD95), developed in 2009 using a laboratory susceptible population, were used to measure changes in susceptibility levels of field-collected populations as compared with a susceptible laboratory population. Further reductions in the susceptibility levels of D. citri to chlorpyriphos and fenpropathrin were determined, compared with results obtained in 2010. Mean percent mortality obtained from all five locations was significantly lower than observed with the laboratory susceptible population for all insecticides tested. Previously, expression of five CYP4 genes was implicated in contributing to insecticide metabolism in D. citri. In the current study, we compared the relative expression of these five CYP4 genes and their associated levels of protein expression among field-collected and laboratory susceptible populations. Expression of all CYP4 genes investigated was higher in field-collected populations when normalized against the laboratory susceptible population. There was an increased signal of a band corresponding to a 45 kDa protein in four of the five field populations as measured by the Western blot assay, which suggests increased production of cytochrome P450 enzymes. The current results indicate that insecticide resistance continues to increase in Florida populations ofD. citri, particularly to chlorpyriphos and fenpropathrin. However, there was no further decrease in susceptibility of Florida populations of D. citri to neonicotinoid insecticides in 2011 as compared with previous years.

Evaluation of the automated system Vitek2 for identification and antimicrobial susceptibility testing of Brazilian Gram-positive cocci strains

Directory of Open Access Journals (Sweden)

Pedro Alves d'Azevedo

Full Text Available Automated instruments offer many advantages for clinical laboratories. Nevertheless, they can have problems identifying and determining susceptibilities of some pathogens. Vitek® 2 (bioMérieux is an automated system that was recently introduced to Brazil. We evaluated the performance of this equipment for Brazilian isolates that had been characterized using reference identification and antimicrobial susceptibility testing methods. Ninety-nine strains of Gram-positive cocci from a local reference center collection were analyzed, consisting of 50 coagulasenegative Staphylococcus (CoNS and 49 Enterococcus and related species. Vitek® 2 correctly identified 79.8% (79/99 of the isolates. Oxacillin resistance was detected in 76% (19/25 of resistant S. epidermidis strains and in 88% (22/25 of other resistant CoNS species strains. Vancomycin resistance was detected in 100% (20/20 of resistant Enterococcus and related species strains. Vitek® 2 performed very well for the identification of S. epidermidis and non-epidermidis staphylococci, and for the detection of vancomycin resistance in Enterococcus and related species. However, the system needs improvement in order to provide reliable results for the characterization of some CoNS species, identification of Enterococcus and related species and for detecting oxacillin resistance in CoNS.

[Comparison of microdilution and disk diffusion methods for the detection of fluconazole and voriconazole susceptibility against clinical Candida glabrata isolates and determination of changing susceptibility with new CLSI breakpoints].

Science.gov (United States)

Hazırolan, Gülşen; Sarıbaş, Zeynep; Arıkan Akdağlı, Sevtap

2016-07-01

Candida albicans is the most frequently isolated species as the causative agent of Candida infections. However, in recent years, the isolation rate of non-albicans Candida species have increased. In many centers, Candida glabrata is one of the commonly isolated non-albicans species of C.glabrata infections which are difficult-to-treat due to decreased susceptibility to fluconazole and cross-resistance to other azoles. The aims of this study were to determine the in vitro susceptibility profiles of clinical C.glabrata isolates against fluconazole and voriconazole by microdilution and disk diffusion methods and to evaluate the results with both the previous (CLSI) and current species-specific CLSI (Clinical and Laboratory Standards Institute) clinical breakpoints. A total of 70 C.glabrata strains isolated from clinical samples were included in the study. The identification of the isolates was performed by morphologic examination on cornmeal Tween 80 agar and assimilation profiles obtained by using ID32C (BioMérieux, France). Broth microdilution and disk diffusion methods were performed according to CLSI M27-A3 and CLSI M44-A2 documents, respectively. The results were evaluated according to CLSI M27-A3 and M44-A2 documents and new vs. species-specific CLSI breakpoints. By using both previous and new CLSI breakpoints, broth microdilution test results showed that voriconazole has greater in vitro activity than fluconazole against C.glabrata isolates. For the two drugs tested, very major error was not observed with disk diffusion method when microdilution method was considered as the reference method. Since "susceptible" category no more exists for fluconazole vs. C.glabrata, the isolates that were interpreted as susceptible by previous breakpoints were evaluated as susceptible-dose dependent by current CLSI breakpoints. Since species-specific breakpoints remain yet undetermined for voriconazole, comparative analysis was not possible for this agent. The results obtained

Multiple Genetic Analysis System-Based Antibiotic Susceptibility Testing in Helicobacter pylori and High Eradication Rate With Phenotypic Resistance-Guided Quadruple Therapy.

Science.gov (United States)

Dong, Fangyuan; Ji, Danian; Huang, Renxiang; Zhang, Fan; Huang, Yiqin; Xiang, Ping; Kong, Mimi; Nan, Li; Zeng, Xianping; Wu, Yong; Bao, Zhijun

2015-11-01

Antibiotics resistance in Helicobacter pylori (H. pylori) is the major factor for eradication failure. Molecular tests including fluorescence in situ hybridization, PCR-restriction fragment length polymorphism, and dual priming oligonucleotide-PCR (DPO-PCR) play critical roles in the detection of antibiotic susceptibility; however, limited knowledge is known about application of multiple genetic analysis system (MGAS) in the area of H. pylori identification and antibiotics resistance detection.The aim of this study is to determine the antibiotics resistance using different molecular tests and evaluate the treatment outcomes of E-test-based genotypic resistance.A total of 297 patients with dyspepsia complaint were recruited for gastroscopies. Ninety patients with H. pylori culture positive were randomly divided into 2 groups (test group and control group). E-test, general PCR, and MGAS assay were performed in test group. Patients in control group were treated with empirical therapy (rabeprazole + bismuth potassium citrate + amoxicillin [AMX] + clarithromycin [CLR]), whereas patients in test group received quadruple therapy based on E-test results twice daily for 14 consecutive days. The eradication effect of H. pylori was confirmed by C-urea breath test after at least 4 weeks when treatment was finished.Rapid urease test showed 46.5% (128/297) patients with H. pylori infection, whereas 30.3% (90/297) patients were H. pylori culture positive. E-test showed that H. pylori primary resistance rate to CLR, AMX, metronidazole, tetracycline, and levofloxacin (LVX) was 40.0% (18/45), 4.4% (2/45), 53.3% (24/45), 0% (0/45), and 55.6% (25/45), respectively. In addition, there are many multidrug resistant (MDR) phenotypes, and the MDR strains have higher minimum inhibitory concentration than their single-drug resistant counterparts. Considering E-test as the reference test, the sensitivities of general PCR and MGAS in detecting CLR resistance were 83.3% (15/18) and 94.4% (17

Antibiotic susceptibility of periodontal Streptococcus constellatus and Streptococcus intermedius clinical isolates.

Science.gov (United States)

Rams, Thomas E; Feik, Diane; Mortensen, Joel E; Degener, John E; van Winkelhoff, Arie J

2014-12-01

Streptococcus constellatus and Streptococcus intermedius in subgingival dental plaque biofilms may contribute to forms of periodontitis that resist treatment with conventional mechanical root debridement/surgical procedures and may additionally participate in some extraoral infections. Because systemic antibiotics are often used in these clinical situations, and little is known of the antibiotic susceptibility of subgingival isolates of these two bacterial species, this study determined the in vitro susceptibility to six antibiotics of fresh S. constellatus and S. intermedius clinical isolates from human periodontitis lesions. A total of 33 S. constellatus and 17 S. intermedius subgingival strains, each recovered from separate patients with severe chronic periodontitis (n = 50) before treatment, were subjected to antibiotic gradient strip susceptibility testing with amoxicillin, azithromycin, clindamycin, ciprofloxacin, and doxycycline on blood-supplemented Mueller-Hinton agar and to the inhibitory effects of metronidazole at 16 mg/L in an enriched Brucella blood agar dilution assay. Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing interpretative standards were used to assess the results. Clindamycin was the most active antibiotic against S. constellatus (minimum inhibitory concentration at 90% [MIC90] 0.25 mg/L), and amoxicillin was most active against S. intermedius (MIC90 0.125 mg/L). A total of 30% of the S. constellatus and S. intermedius clinical isolates were resistant in vitro to doxycycline, 98% were only intermediate in susceptibility to ciprofloxacin, and 90% were resistant to metronidazole at 16 mg/L. Subgingival S. constellatus and S. intermedius exhibited variable antibiotic susceptibility profiles, potentially complicating empirical selection of periodontitis antibiotic therapy in patients who are species positive.

Antimicrobial susceptibility of Clostridium difficile isolated in Thailand

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Papanin Putsathit

2017-06-01

Full Text Available Abstract Background Exposure to antimicrobials is the major risk factor associated with Clostridium difficile infection (CDI. Paradoxically, treatment of CDI with antimicrobials remains the preferred option. To date, only three studies have investigated the antimicrobial susceptibility of C. difficile from Thailand, two of which were published in the 1990s. This study aimed to investigate the contemporary antibiotic susceptibility of C. difficile isolated from patients in Thailand. Methods A collection of 105 C. difficile isolated from inpatients admitted at Siriraj Hospital in Bangkok in 2015 was tested for their susceptibility to nine antimicrobials via an agar incorporation method. Results All isolates were susceptible to vancomycin, metronidazole, amoxicillin/clavulanate and meropenem. Resistance to clindamycin, erythromycin and moxifloxacin was observed in 73.3%, 35.2% and 21.0% of the isolates, respectively. The in vitro activity of fidaxomicin (MIC50/MIC90 0.06/0.25 mg/L was superior to first-line therapies vancomycin (MIC50/MIC90 1/2 mg/L and metronidazole (MIC50/MIC90 0.25/0.25 mg/L. Rifaximin exhibited potent activity against 85.7% of the isolates (MIC ≤0.03 mg/L, and its MIC50 (0.015 mg/L was the lowest among all antimicrobials tested. The prevalence of multi-drug resistant C. difficile, defined by resistance to ≥3 antimicrobials, was 21.9% (23/105. Conclusions A high level of resistance against multiple classes of antimicrobial was observed, emphasising the need for enhanced antimicrobial stewardship and educational programmes to effectively disseminate information regarding C. difficile awareness and appropriate use of antimicrobials to healthcare workers and the general public.

Analytic laboratory performance of a point of care urine culture kit for diagnosis and antibiotic susceptibility testing.

Science.gov (United States)

Bongard, E; Frimodt-Møller, N; Gal, M; Wootton, M; Howe, R; Francis, N; Goossens, H; Butler, C C

2015-10-01

Currently available point-of-care (POC) diagnostic tests for managing urinary tract infections (UTIs) in general practice are limited by poor performance characteristics, and laboratory culture generally provides results only after a few days. This laboratory evaluation compared the analytic performance of the POC UK Flexicult(™) (Statens Serum Institut) (SSI) urinary kit for quantification, identification and antibiotic susceptibility testing and routine UK National Health Service (NHS) urine processing to an advanced urine culture method. Two hundred urine samples routinely submitted to the Public Health Wales Microbiology Laboratory were divided and: (1) analysed by routine NHS microbiological tests as per local laboratory standard operating procedures, (2) inoculated onto the UK Flexicult(™) SSI urinary kit and (3) spiral plated onto Colorex Orientation UTI medium (E&O Laboratories Ltd). The results were evaluated between the NHS and Flexicult(™ )methods, and discordant results were compared to the spiral plating method. The UK Flexicult(™) SSI urinary kit was compared to routine NHS culture for identification of a pure or predominant uropathogen at ≥ 10(5) cfu/mL, with a positive discordancy rate of 13.5% and a negative discordancy rate of 3%. The sensitivity and specificity were 86.7% [95% confidence interval (CI) 73.8-93.7] and 82.6% (95% CI 75.8-87.7), respectively. The UK Flexicult(™) SSI urinary kit was comparable to routine NHS urine processing in identifying microbiologically positive UTIs in this laboratory evaluation. However, the number of false-positive samples could lead to over-prescribing of antibiotics in clinical practice. The Flexicult(™) SSI kit could be useful as a POC test for UTIs in primary care but further pragmatic evaluations are necessary.

Genetic architecture for susceptibility to gout in the KARE cohort study.

Science.gov (United States)

Shin, Jimin; Kim, Younyoung; Kong, Minyoung; Lee, Chaeyoung

2012-06-01

This study aimed to identify functional associations of cis-regulatory regions with gout susceptibility using data resulted from a genome-wide association study (GWAS), and to show a genetic architecture for gout with interaction effects among genes within each of the identified functions. The GWAS was conducted with 8314 control subjects and 520 patients with gout in the Korea Association REsource cohort. However, genetic associations with any individual nucleotide variants were not discovered by Bonferroni multiple testing in the GWAS (P>1.42 × 10(-7)). Genomic regions enrichment analysis was employed to identify functional associations of cis-regulatory regions. This analysis revealed several biological processes associated with gout susceptibility, and they were quite different from those with serum uric acid level. Epistasis for susceptibility to gout was estimated using entropy decomposition with selected genes within each biological process identified by the genomic regions enrichment analysis. Some epistases among nucleotide sequence variants for gout susceptibility were found to be larger than their individual effects. This study provided the first evidence that genetic factors for gout susceptibility greatly differed from those for serum uric acid level, which may suggest that research endeavors for identifying genetic factors for gout susceptibility should not be heavily dependent on pathogenesis of uric acid. Interaction effects between genes should be examined to explain a large portion of phenotypic variability for gout susceptibility.

Phosphorylcholine impairs susceptibility to biofilm formation of hydrogel contact lenses.

Science.gov (United States)

Selan, Laura; Palma, Stefano; Scoarughi, Gian Luca; Papa, Rosanna; Veeh, Richard; Di Clemente, Daniele; Artini, Marco

2009-01-01

To compare silicone-hydrogel, poly(2-hydroxyethyl methacrylate) (pHEMA), and phosphorylcholine-coated (PC-C) contact lenses in terms of their susceptibility to biofilm formation by Staphylococcus epidermidis and Pseudomonas aeruginosa. Laboratory investigation. Biofilm formation on colonized test lenses was evaluated with confocal microscopy and in vitro antibiotic susceptibility assays. The results of the latter assays were compared with those performed on planktonic cultures of the same organism. For both microorganisms, sessile colonies on silicone-hydrogel and pHEMA lenses displayed lower antibiotic susceptibility than their planktonic counterparts. In contrast, the susceptibility of cultures growing on PC-C lenses was comparable with that for planktonic cultures. In particular, minimum inhibitory concentration for Tazocin (piperacillin plus tazobactam; Wyeth Pharmaceuticals, Aprilia, Italy; S. epidermidis) and gentamicin (P. aeruginosa) was identical, either in the presence of PC-C support or in planktonic cultures (Tazocin, aeruginosa) was two-fold higher for PC-C lenses (0.4 mug/ml) with respect to planktonic cultures (0.2 mug/ml). Confocal microscopy of lenses colonized for 24 hours with P. aeruginosa green fluorescent protein-expressing cells revealed a sessile colonization on silicone-hydrogel lens and a few isolated bacterial cells scattered widely over the surface of the PC-C lens. An increase in antibiotic susceptibility of bacterial cultures was associated with diminished bacterial adhesion. Our results indicate that PC-C lenses seem to be more resistant than silicone-hydrogel and pHEMA lenses to bacterial adhesion and colonization. This feature may facilitate their disinfection.

Test results of Salmonella typing by the NRLs-Salmonella in the Member States of the EU and the EnterNet Laboratories - Collaborative study VI on typing of Salmonella

NARCIS (Netherlands)

Korver H; Raes M; Maas HME; Ward LR; Wannet WJB; Henken AM; PHLS-Colindale/London; MGB; LIS

2002-01-01

Test results of Salmonella sero- and phage typing and antimicrobial susceptibility testing by the National Reference Laboratories for Salmonella in the Member States of the European Union and the EnterNet Laboratories: Collaborative study VI (2001) for Salmonella. The sixth collaborative typing

Magnetic susceptibility measurements on Bi - Sn alloys

International Nuclear Information System (INIS)

Mustaffa bin Haji Abdullah

1985-01-01

Magnetic susceptibility measurements on eight samples of tin-rich and three samples of bismuth-rich Bi-Sn alloys were made from 85K to 300K by Faraday's method. The susceptibilities of the eight tin-rich samples are positive and greater than the susceptibility of pure tin. The values are approximately constant at low temperatures but decreasing a little bit with increasing temperature. This result is interpreted as due to the predominant contribution of the Pauli spin paramagnetic susceptibility. A small decrease in susceptibility with temperature is interpreted as due to the effect of the second order term in the expression for spin paramagnetic susceptibility. The fluctuation of the susceptibility for alloys of different composition is interpreted as due to the effect of the density of states at the Fermi levels. The three samples of bismuth-rich alloys show a transition to diamagnetic property, where the diamagnetism is increased with temperature. This result is predominant and due to the diamagnetic contribution from the ions. The increase in susceptibility with temperature is interpreted as due to an increase in the effective radii of the ions due to thermal expansion. (author)

Rapid Isolation and Susceptibility Testing of Leptospira spp. Using a New Solid Medium, LVW Agar

Science.gov (United States)

Wuthiekanun, Vanaporn; Amornchai, Premjit; Paris, Daniel H.; Langla, Sayan; Thaipadunpanit, Janjira; Chierakul, Wirongrong; Smythe, Lee D.; White, Nicholas J.; Day, Nicholas P. J.; Peacock, Sharon J.

2013-01-01

Pathogenic Leptospira spp., the causative agents of leptospirosis, are slow-growing Gram-negative spirochetes. Isolation of Leptospira from clinical samples and testing of antimicrobial susceptibility are difficult and time-consuming. Here, we describe the development of a new solid medium that facilitates more-rapid growth of Leptospira spp. and the use of this medium to evaluate the Etest's performance in determining antimicrobial MICs to drugs in common use for leptospirosis. The medium was developed by evaluating the effects of numerous factors on the growth rate of Leptospira interrogans strain NR-20157. These included the type of base agar, the concentration of rabbit serum (RS), and the concentration and duration of CO2 incubation during the initial period of culture. The highest growth rate of NR-20157 was achieved using a Noble agar base supplemented with 10% RS (named LVW agar), with an initial incubation at 30°C in 5% CO2 for 2 days prior to continuous culture in air at 30°C. These conditions were used to develop the Etest for three species, L. interrogans (NR-20161), L. kirschnerii (NR-20327), and L. borgpetersenii (NR-20151). The MICs were read on day 7 for all samples. The Etest was then performed on 109 isolates of pathogenic Leptospira spp. The MIC90 values for penicillin G, doxycycline, cefotaxime, ceftriaxone, and chloramphenicol were 0.64 units/ml and 0.19, 0.047, 0.5, and 2 μg/ml, respectively. The use of LVW agar, which enables rapid growth, isolation of single colonies, and simple antimicrobial susceptibility testing for Leptospira spp., provides an opportunity for new areas of fundamental and applied research. PMID:23114772

Mean magnetic susceptibility regularized susceptibility tensor imaging (MMSR-STI) for estimating orientations of white matter fibers in human brain.

Science.gov (United States)

Li, Xu; van Zijl, Peter C M

2014-09-01

An increasing number of studies show that magnetic susceptibility in white matter fibers is anisotropic and may be described by a tensor. However, the limited head rotation possible for in vivo human studies leads to an ill-conditioned inverse problem in susceptibility tensor imaging (STI). Here we suggest the combined use of limiting the susceptibility anisotropy to white matter and imposing morphology constraints on the mean magnetic susceptibility (MMS) for regularizing the STI inverse problem. The proposed MMS regularized STI (MMSR-STI) method was tested using computer simulations and in vivo human data collected at 3T. The fiber orientation estimated from both the STI and MMSR-STI methods was compared to that from diffusion tensor imaging (DTI). Computer simulations show that the MMSR-STI method provides a more accurate estimation of the susceptibility tensor than the conventional STI approach. Similarly, in vivo data show that use of the MMSR-STI method leads to a smaller difference between the fiber orientation estimated from STI and DTI for most selected white matter fibers. The proposed regularization strategy for STI can improve estimation of the susceptibility tensor in white matter. © 2014 Wiley Periodicals, Inc.

Susceptibility of Staphylococcus species and subspecies to teicoplanin.

Science.gov (United States)

Bannerman, T L; Wadiak, D L; Kloos, W E

1991-01-01

Twenty-four Staphylococcus species and their subspecies were examined for their susceptibilities to teicoplanin by disk diffusion (30-micrograms disk) and agar dilution for the determination of MICs. Moderately susceptible and resistant clinical strains were further tested for their susceptibilities to oxacillin and vancomycin. Teicoplanin resistance was not observed in the reference strains of the various Staphylococcus species isolated from healthy volunteers or animals. However, the novobiocin-resistant species Staphylococcus saprophyticus, Staphylococcus cohnii, Staphylococcus xylosus, Staphylococcus arlettae, Staphylococcus kloosii, and Staphylococcus gallinarum were less susceptible to teicoplanin (MIC, 2 to 8 micrograms/ml) than most of the novobiocin-susceptible species were (MIC, 0.5 to 4 micrograms/ml). Clinical isolates of coagulase-negative species were generally less susceptible to teicoplanin than were reference strains. Seven percent of the Staphylococcus epidermidis clinical strains were moderately susceptible (MIC, 16 micrograms/ml) to teicoplanin. Of these strains, 70% were oxacillin resistant. For Staphylococcus haemolyticus strains, 11% were resistant (MIC, greater than 16 micrograms/ml) and 21% were moderately susceptible to teicoplanin. Of these strains, 95% were oxacillin resistant, No strains of S. epidermidis or S. haemolyticus were intermediate or resistant to vancomycin. Teicoplanin appears to be less active in vitro against oxacillin-resistant S. haemolyticus. However, teicoplanin is an effective antimicrobial agent against many Staphylococcus species. PMID:1835340

The relative stress-corrosion-cracking susceptibility of candidate aluminum-lithium alloys for aerospace applications

Science.gov (United States)

Pizzo, P. P.

1982-01-01

Stress corrosion tests of Al-Li-Cu powder metallurgy alloys are described. Alloys investigated were Al-2.6% Li-1.4% and Al-2.6% Li-1.4% Cu-1.6% Mg. The base properties of the alloys were characterized. Process, heat treatment, and size/orientational effects on the tensile and fracture behavior were investigated. Metallurgical and electrochemical conditions are identified which provide reproducible and controlled parameters for stress corrosion evaluation. Preliminary stress corrosion test results are reported. Both Al-Li-Cu alloys appear more susceptible to stress corrosion crack initiation than 7075-T6 aluminum, with the magnesium bearing alloy being the most susceptible. Tests to determine the threshold stress intensity for the base and magnesium bearing alloys are underway. Twelve each, bolt loaded DCB type specimens are under test (120 days) and limited crack growth in these precracked specimens has been observed. General corrosion in the aqueous sodium chloride environment is thought to be obscuring results through crack tip blunting.

Topological Susceptibility from Slabs

CERN Document Server

Bietenholz, Wolfgang; Gerber, Urs

2015-01-01

In quantum field theories with topological sectors, a non-perturbative quantity of interest is the topological susceptibility chi_t. In principle it seems straightforward to measure chi_t by means of Monte Carlo simulations. However, for local update algorithms and fine lattice spacings, this tends to be difficult, since the Monte Carlo history rarely changes the topological sector. Here we test a method to measure chi_t even if data from only one sector are available. It is based on the topological charges in sub-volumes, which we denote as slabs. Assuming a Gaussian distribution of these charges, this method enables the evaluation of chi_t, as we demonstrate with numerical results for non-linear sigma-models.

Evaluation of the Sensititre MycoTB plate for susceptibility testing of the Mycobacterium tuberculosis complex against first- and second-line agents.

Science.gov (United States)

Hall, Leslie; Jude, Kurt P; Clark, Shirley L; Dionne, Kim; Merson, Ryan; Boyer, Ana; Parrish, Nicole M; Wengenack, Nancy L

2012-11-01

The Sensititre MycoTB plate (TREK Diagnostic Systems, Cleveland, OH) uses a microtiter plate MIC format for susceptibility testing of Mycobacterium tuberculosis complex isolates against first- and second-line antituberculosis agents. Categorical agreement versus the agar proportion method for 122 M. tuberculosis complex isolates was 94% to 100%.

Monitoring of antimicrobial susceptibility of respiratory tract pathogens isolated from diseased cattle and pigs across Europe, 2009-2012: VetPath results.

Science.gov (United States)

El Garch, Farid; de Jong, Anno; Simjee, Shabbir; Moyaert, Hilde; Klein, Ulrich; Ludwig, Carolin; Marion, Hervé; Haag-Diergarten, Silke; Richard-Mazet, Alexandra; Thomas, Valérie; Siegwart, Ed

2016-10-15

VetPath is an ongoing pan-European antibiotic susceptibility monitoring programme that collects pathogens from diseased cattle, pigs and poultry. In the current study, 996 isolates from cattle and pig respiratory tract infections were tested for their antimicrobial susceptibilities. Non-replicate lung samples or nasopharyngeal/nasal swabs were collected from animals with acute clinical signs in 10 countries during 2009-2012. Pasteurella multocida, Mannheimia haemolytica and Histophilus somni from cattle and P. multocida, Actinobacillus pleuropneumoniae, Haemophilus parasuis, Bordetella bronchiseptica and Streptococcus suis from pigs were isolated by standard methods. S. suis was also isolated from meningitis cases. MIC values of 16 or 17 antibiotics were assessed centrally by broth microdilution following CLSI standards. Results were interpreted using CLSI breakpoints where available. Cattle isolates were generally highly susceptible to most antibiotics, except to tetracycline (3.0-12.0% resistance). Low levels of resistance (0-4.0%) were observed for the macrolide antibiotics. Resistance to spectinomycin varied from 0 to 6.0%. In pig isolates similar observations were made. Resistance to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin, florfenicol, tulathromycin, tiamulin and tilmicosin was absent or <2%. Trimethoprim/sulfamethoxazole resistance varied from 1.9 to 5.3%, but tetracycline resistance varied from 20.4% in P. multocida to 88.1% in S. suis. For most antibiotics and pathogens the percentage resistance remained unchanged or only increased numerically as compared to that of the period 2002-2006. In conclusion, absence or low resistance to antibiotics with defined clinical breakpoints, except for tetracycline, was observed among the major respiratory tract pathogens recovered from livestock. Comparison of all antibiotics and organisms was hampered since for almost half of the antibiotics no CLSI-defined breakpoints were available. Copyright © 2016

Comparison of methods for in vitro testing of susceptibility of porcine Mycoplasma species to antimicrobial agents.

Science.gov (United States)

Ter Laak, E A; Pijpers, A; Noordergraaf, J H; Schoevers, E C; Verheijden, J H

1991-02-01

The MICs of 18 antimicrobial agents used against strains of three porcine Mycoplasma species were determined by a serial broth dilution method. Twenty field strains of M. hyorhinis, ten field strains of M. hyopneumoniae, six field strains of M. flocculare, and the type strains of these species were tested. Twelve field strains and the type strain of M. hyorhinis were also tested by an agar dilution method. Tests were read at various time points. When the broth dilution method was used, the final MIC had to be read 2 days after color changes had stopped. MICs of tetracycline, oxytetracycline, doxycycline, and minocycline were low for the three Mycoplasma species tested. MICs of chlortetracycline were 8 to 16 times higher than MICs of the other tetracyclines. Spiramycin, tylosin, kitasamycin, spectinomycin, tiamulin, lincomycin, and clindamycin were effective against all strains of M. hyorhinis and M. hyopneumoniae. The quinolones were highly effective against M. hyopneumoniae but less effective against M. hyorhinis. The susceptibility patterns for M. hyopneumoniae and M. flocculare were similar.

Predicament in detection and reporting of extended spectrum beta lactamase production in routine antibiotic susceptibility testing

International Nuclear Information System (INIS)

Butt, T.; Butt, E.; Raza, S.

2017-01-01

This descriptive and cross-sectional study was planned to determine the dilemma of inadvertent detection of extended spectrum beta lactamase (ESBL) production in Enterobacteriaceaewhen using inhibition zone size of antibiotic disks of Cefotaxime or Aztreonam in routine antibiotic susceptibility testing as recommended by Clinical Laboratory Standards Institute (CLSI). Screening and double disk tests were adopted as per CLSI. Escherichia coli ATCC 25922 was used as control strain. Among total specimens of 5346, there were 348 isolates of Escherichia coli(n=235), Klebsiella pneumonia (n=92), Klebsiella oxytoca(n=3) or Proteus mirabilus(n=18). The screening method recommended by CLSI significantly falsely detected ESBL production in 79 (32.3%) isolates (p<0.0001). ESBL detection is important as its frequency is high and treatment of the infection varies with the presence and absence of ESBL. To avoid false reporting, proper phenotypic detection of ESBL confirmatory method-like double-disk synergy test, should be used routinely. (author)

Determination of antifungal susceptibility patterns among the clinical isolates of Candida species

Directory of Open Access Journals (Sweden)

Kamiar Zomorodian

2011-01-01

Full Text Available Context: Candida species are opportunistic yeasts that cause infections ranging from simple dermatosis to potentially life-threatening fungemia. The emergence of resistance to antifungal drugs has been increased in the past two decades. Aim: the present study we determined to find out the susceptibility profiles of clinical isolates of Candida species against four antifungal drugs, including amphotericin B, ketoconazole, fluconazole and itraconazole. Materials and Methods: Antifungal susceptibility testing of the yeasts was done in accordance with the proposed guidelines for antifungal disk diffusion susceptibility testing of yeasts based on the CLSI document M44-A. Results: A total of 206 yeast isolates were assessed. Among the evaluated Candida species, the highest rates of resistance to ketoconazole were seen in Candida glabrata (16.6% and Candida albicans (3.2%. Susceptibility and intermediate response to fluconazole were seen in 96.6% and 3.4% of the Candida isolates, respectively. A total of 19 (9.2% yeast isolates showed petite phenomenon including 11 C. glabrata, 3 C. albicans, 2 Candida dubliniensis and one isolate of each Candida krusei and Candida parapsilosis. Conclusion: The high number of petite mutation in the isolated yeasts should be seriously considered since it may be one of the reasons of antifungal treatment failure.

Differences in susceptibility of five cladoceran species to two systemic insecticides, imidacloprid and fipronil.

Science.gov (United States)

Hayasaka, Daisuke; Korenaga, Tomoko; Suzuki, Kazutaka; Sánchez-Bayo, Francisco; Goka, Koichi

2012-03-01

Differences in susceptibility of five cladocerans to the neonicotinoid imidacloprid and the phenyl-pyrazole fipronil, which have been dominantly used in rice fields of Japan in recent years, were examined based on short-term (48-h), semi-static acute immobilization exposure tests. Additionally, we compared the species sensitivity distribution (SSD) patterns of both insecticides between two sets of species: the five tested cladocerans and all other aquatic organisms tested so far, using data from the ECOTOX database of U.S. Environmental Protection Agency (USEPA). The sensitivity of the test species to either imidacloprid or fipronil was consistent, spanning similar orders of magnitude (100 times). At the genus level, sensitivities to both insecticides were in the following descending order: Ceriodaphnia > Moina > Daphnia. A positive relationship was found between body lengths of each species and the acute toxicity (EC(50)) of the insecticides, in particular fipronil. Differences in SSD patterns of imidacloprid were found between the species groups compared, indicating that test cladocerans are much less susceptible than other aquatic species including amphibians, crustaceans, fish, insects, mollusks and worms. However, the SSD patterns for fipronil indicate no difference in sensitivity between cladocerans tested and other aquatic organisms despite the greater exposure, which overestimates the results, of our semi-static tests. From these results, Ceriodaphnia sp. should be considered as more sensitive bioindicators (instead of the standard Daphnia magna) for ecotoxicological assessments of aquatic ecosystems. In addition, we propose that ecotoxicity data associated with differences in susceptibility among species should be investigated whenever pesticides have different physicochemical properties and mode of action.

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...

Emerging Resistance, New Antimicrobial Agents  …  but No Tests! The Challenge of Antimicrobial Susceptibility Testing in the Current US Regulatory Landscape.

Science.gov (United States)

Humphries, R M; Hindler, J A

2016-07-01

Accurate and timely performance of antimicrobial susceptibility testing (AST) by the clinical laboratory is paramount to combating antimicrobial resistance. The ability of laboratories in the United States to effectively perform ASTs is challenged by several factors. Some, such as new resistance mechanisms and the associated evolution of testing recommendations and breakpoints, are inevitable. Others are entirely man-made. These include unnecessarily strict US Food and Drug Administration (FDA) limitations on how commercial AST systems can be used for diagnostic testing, the absence of up-to-date performance data on these systems, and the lack of commercially available FDA-cleared tests for newer antimicrobial agents or for older agents with updated breakpoints. This viewpoint will highlight contemporary AST challenges faced by the clinical laboratory, and propose some solutions. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Ranking alloys for susceptibility to MIC

International Nuclear Information System (INIS)

Scott, P.J.B.; Davies, M.; Goldie, J.

1991-01-01

This paper reports that laboratory experiments demonstrate that alloys containing 6 to 9% Mo are susceptible to microbiologically influenced corrosion attack. They also demonstrate that corrosion behavior in batch cultures do not correlate well with standard ferric chloride and pitting potential tests of the same alloys. In recent years, there has been an increasing awareness of the incidence of plant equipment failures caused by microbiologically influenced corrosion (MIC). This has led to the search for suitable testing techniques to look for MIC, which, in turn, has expanded the list of known susceptible alloys. Faced with field failures, the normal response has been to upgrade the alloy of construction. There is, for example, a common belief that the addition of more molybdenum to austenitic stainless steels conveys immunity (or at least increased resistance) to MIC. The basis for this is an extrapolation of localized corrosion data. The supposed correlation between molybdenum content and resistance to MIC has not yet been supported by a comprehensive testing program

Microbial identification and automated antibiotic susceptibility testing directly from positive blood cultures using MALDI-TOF MS and VITEK 2.

Science.gov (United States)

Wattal, C; Oberoi, J K

2016-01-01

The study addresses the utility of Matrix Assisted Laser Desorption/Ionisation Time-Of-Flight mass spectrometry (MALDI-TOF MS) using VITEK MS and the VITEK 2 antimicrobial susceptibility testing (AST) system for direct identification (ID) and timely AST from positive blood culture bottles using a lysis-filtration method (LFM). Between July and December 2014, a total of 140 non-duplicate mono-microbial blood cultures were processed. An aliquot of positive blood culture broth was incubated with lysis buffer before the bacteria were filtered and washed. Micro-organisms recovered from the filter were first identified using VITEK MS and its suspension was used for direct AST by VITEK 2 once the ID was known. Direct ID and AST results were compared with classical methods using solid growth. Out of the 140 bottles tested, VITEK MS resulted in 70.7 % correct identification to the genus and/ or species level. For the 103 bottles where identification was possible, there was agreement in 97 samples (94.17 %) with classical culture. Compared to the routine method, the direct AST resulted in category agreement in 860 (96.5 %) of 891 bacteria-antimicrobial agent combinations tested. The results of direct ID and AST were available 16.1 hours before those of the standard approach on average. The combined use of VITEK MS and VITEK 2 directly on samples from positive blood culture bottles using a LFM technique can result in rapid and reliable ID and AST results in blood stream infections to result in early institution of targeted treatment. The combination of LFM and AST using VITEK 2 was found to expedite AST more reliably.

Studies on the susceptibility of peas and field peas cultivars to Ascochyta pisi (Lib.

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Helena Furgał-Węgrzycka

2013-12-01

Full Text Available The aim of the work was to find the plants resistant to Ascochyta pisi causing leaf and spot-pot of peas and field peas. Fourty five cultivars of peas and field peas and 6 breeding materials were tested in field in the period 1975-1978. Cultivars: Bartel, Birte, Borek, Cebeco, Finale and Paloma were to be less susceptible. In laboratory and greenhouse conditions peas and field peas cultivares were examined for susceptible to pathotypes 2 and 4 of Ascochyta pisi. The results obtained proved that cultivars: Borel, cebeco, Finale and Paloma were to be less susceptible to two pathotypes of Ascochyta pisi.

Has introduction of rapid drug susceptibility testing at diagnosis impacted treatment outcomes among previously treated tuberculosis patients in Gujarat, India?

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Paresh Dave

Full Text Available Revised National TB Control Programme (RNTCP in India recommends that all previously-treated TB (PT patients are offered drug susceptibility testing (DST at diagnosis, using rapid diagnostics and screened out for rifampicin resistance before being treated with standardized, eight-month, retreatment regimen. This is intended to improve the early diagnosis of rifampicin resistance and its appropriate management and improve the treatment outcomes among the rest of the patients. In this state-wide study from Gujarat, India, we assess proportion of PT patients underwent rapid DST at diagnosis and the impact of this intervention on their treatment outcomes.This is a retrospective cohort study involving review of electronic patient-records maintained routinely under RNTCP. All PT patients registered for treatment in Gujarat during January-June 2013 were included. Information on DST and treatment outcomes were extracted from 'presumptive DR-TB patient register' and TB treatment register respectively. We performed a multivariate analysis to assess if getting tested is independently associated with unfavourable outcomes (death, loss-to-follow-up, failure, transfer out.Of 5,829 PT patients, 5306(91% were tested for drug susceptibility with rapid diagnostics. Overall, 71% (4,113 TB patients were successfully treated - 72% among tested versus 60% among non-tested. Patients who did not get tested at diagnosis had a 34% higher risk of unsuccessful outcomes as compared to those who got tested (aRR - 1.34; 95% CI 1.20-1.50 after adjusting for age, sex, HIV status and type of TB. Unfavourable outcomes (particularly failure and switched to category IV were higher among INH-resistant patients (39% as compared to INH-sensitive (29%.Offering DST at diagnosis improved the treatment outcomes among PT patients. However, even among tested, treatment outcomes remained suboptimal and were related to INH resistance and high loss-to-follow-up. These need to be addressed

Extended spectrum of antibiotic susceptibility for tuberculosis, Djibouti.

Science.gov (United States)

Bouzid, Fériel; Astier, Hélène; Osman, Djaltou Aboubaker; Javelle, Emilie; Hassan, Mohamed Osman; Simon, Fabrice; Garnotel, Eric; Drancourt, Michel

2018-02-01

In the Horn of Africa, there is a high prevalence of tuberculosis that is reported to be partly driven by multidrug-resistant (MDR) Mycobacterium tuberculosis strictu sensu strains. We conducted a prospective study to investigate M. tuberculosis complex species causing tuberculosis in Djibouti, and their in vitro susceptibility to standard anti-tuberculous antibiotics in addition to clofazimine, minocycline, chloramphenicol and sulfadiazine. Among the 118 mycobacteria isolates from 118 successive patients with suspected pulmonary tuberculosis, 111 strains of M. tuberculosis, five Mycobacterium canettii, one 'Mycobacterium simulans' and one Mycobacterium kansasii were identified. Drug-susceptibility tests performed on the first 78 isolates yielded nine MDR M. tuberculosis isolates. All isolates were fully susceptible to clofazimine, minocycline and chloramphenicol, and 75 of 78 isolates were susceptible to sulfadiazine. In the Horn of Africa, patients with confirmed pulmonary tuberculosis caused by an in vitro susceptible strain may benefit from anti-leprosy drugs, sulfamides and phenicol antibiotics. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Possible individual variation in susceptibility to radiation-induced genetic changes

International Nuclear Information System (INIS)

Gentner, N.E.; Walker, J.A.

1990-01-01

Several studies have shown variation between individuals in radiosensitivity. A person could have a high level of cytogenetic indicator because of high exposure or high susceptibility. To relate spontaneous cytogenetic end-points to dose it is advisable to have a measure of both the spontaneous level and of induced susceptibility. These end points need to be compared in irradiated persons who have developed cancer versus those who have not, as a guide to what end points are appropriate for susceptibility to radiogenic cancer. The use of inbred rodent strains may not be appropriate to derive specific locus mutation data relevant to the human situation, in which large differences in susceptibility appear to exist. Variability in response because of differential DNA repair capacity should be kept in mind when evaluating existing human data. For accident situations, using acute exposures for testing susceptibility may be appropriate, but to be relevant to low dose, low dose rate exposures, more use of protracted dose delivery in testing is recommended. There is a need for international collaborative study where these different tests are done on the same donors at the same time. It might now be prudent for radiation protection to take into account the occurrence of critical groups in the population on the basis of their increased radiation sensitivity. (12 refs., 3 figs.)

A laboratory study of susceptibility of methicillin resistant staphylococcus aureus (MRSA)

International Nuclear Information System (INIS)

Bukhari, M.H.; Iqbal, N.; Naeem, S.; Qureshi, G.R.; Naveed, I.A.; Iqbal, A.; Khatoon, N.

2004-01-01

Objective: To study the mode of infection, incidence of methicillin resistant staphylococcus aureus (MRSA) and their susceptibility against glycopeptides and fucidic acid, so that awareness may be created for consultants against such notorious rapidly spreading bacteria and recommendation can be made for their prevention and control. Methods: The specimens from various infections suspected on clinical ground were processed by standard methods and antibiotic susceptibility testing of all the 350 S. aureus and 135 MRSA isolates was done by using modified Kirby Bauer Disc diffusion technique. Results: Of 350 positive S.aureus cultures, 135 were found to be Methicillin resistant (38.5%) which showed susceptibility 96%, 94% and 86% to Vancomycin, Teicoplanin and Fucidic acid respectively. Conclusion: This study showed a high incidence of MRSA at Mayo Hospital Lahore, Glycopeptides and Fucidic acid were found to be valuable antibiotics against MRSA. (author)

Helicobacter pylori : Prevalence and antibiotic susceptibility among ...

African Journals Online (AJOL)

patients, its relationship with gastric pathologies, and associated antibiotic susceptibility profiles, and compared two media to find the appropriate medium that enhances growth and expedites culture and isolation. Methods. Rapid urease and histological tests were used to screen for H. pylori. Culture was performed to test ...

No support for HLA-DQ encoded susceptibility in rheumatoid arthritis

NARCIS (Netherlands)

de Vries, N. [=Niek; van Elderen, C.; Tijssen, H.; van Riel, P. L.; van de Putte, L. B.

1999-01-01

To test predictions based on data from immunogenetic and peptide-binding studies of collagen-induced arthritis in mice, in which it has been suggested that susceptibility to rheumatoid arthritis (RA) might be determined by the interaction between susceptibility alleles at the HLA-DQ locus and

Magnetic susceptibility characterisation of superparamagnetic microspheres

Science.gov (United States)

Grob, David Tim; Wise, Naomi; Oduwole, Olayinka; Sheard, Steve

2018-04-01

The separation of magnetic materials in microsystems using magnetophoresis has increased in popularity. The wide variety and availability of magnetic beads has fuelled this drive. It is important to know the magnetic characteristics of the microspheres in order to accurately use them in separation processes integrated on a lab-on-a-chip device. To investigate the magnetic susceptibility of magnetic microspheres, the magnetic responsiveness of three types of Dynabeads microspheres were tested using two different approaches. The magnetophoretic mobility of individual microspheres is studied using a particle tracking system and the magnetization of each type of Dynabeads microsphere is measured using SQUID relaxometry. The magnetic beads' susceptibility is obtained at four different applied magnetic fields in the range of 38-70 mT for both the mobility and SQUID measurements. The susceptibility values in both approaches show a consistent magnetic field dependence.

Determination of susceptibility to intergranular corrosion of stainless steels type X5CrNi18-10 in field

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Bore V. Jegdic

2016-12-01

Full Text Available In this paper, the DL EPR method (electrochemical potentiokinetic reactivation with double loop was modified and used to study the susceptibility to intergranular corrosion and stress corrosion cracking of a stainless steel type X5CrNi18-10. The tests were performed in a special electrochemical cell, with the electrolyte in the gel form. Modified DL EPR method is characterized by simple and high accuracy measurements as well as repeatability of the test results. The indicator of susceptibility to intergranular corrosion (Qr/QpGBA obtained by modified DL EPR method is in a very good agreement with the same indicator obtained by standard DL EPR method. The modified DL EPR method is quantitative and highly selective method. Small differences in the susceptibility of the stainless steel type CrNi18-10 to intergranular corrosion and stress corrosion cracking can be determined. Test results can be obtained in a short time. The cost of tests performed by modified DL EPR method is much lower than the cost of tests by conventional chemical methods. Modified DL EPR method can be applied in the field on the stainless steels constructions.

Antibiotic susceptibility profiles of anaerobic pathogens in The Netherlands.

Science.gov (United States)

Veloo, A C M; van Winkelhoff, A J

2015-02-01

The antibiotic susceptibility profile of the Bacteroides fragilis group, Gram-positive anaerobic cocci (GPAC), Fusobacterium spp., Prevotella spp., Veillonella spp. and Bilophila wadsworthia for amoxicillin, amoxicillin-clavulanic acid, clindamycin and metronidazole was determined. Human clinical isolates were isolated between 2011 and 2013 at the Microbiological Diagnostic Laboratory of the University Medical Center Groningen, The Netherlands and subjected to MALDI-TOF MS identification and susceptibility testing using E-test for MIC determination. Differences in clindamycin susceptibility between species of the B. fragilis group and GPAC were observed, with Bacteroides ovatus and Peptoniphilus harei having the highest resistance rates. Compared to other European countries, in The Netherlands the MIC90 for clindamycin of fusobacteria is low. Metronidazole resistance was first encountered in the genus Prevotella in 2013, but not in species of GPAC as reported in Belgium and Bulgaria. The differences in clindamycin resistance between the different European countries and reports of metronidazole resistance within the genera Prevotella and GPAC warrant more extensive susceptibility studies on anaerobic pathogens. Copyright © 2014 Elsevier Ltd. All rights reserved.

Presence-only approach to assess landslide triggering-thickness susceptibility. A test for the Mili catchment (North-Eastern Sicily, Italy)

Science.gov (United States)

Lombardo, Luigi; Fubelli, Giandomenico; Amato, Gabriele; Bonasera, Mauro; Hochschild, Volker; Rotigliano, Edoardo

2015-04-01

thicknesses. In addition, the role of each predictor within the whole modelling procedure was assessed by applying Jackknife tests. These analyses focussed on evaluating the variation of AUC values across replicates comparing single variable models with models based on the full set of predictors iteratively deprived of one covariate. As a result, relevant differences among main contributors between the two considered classes were also quantitatively derived and geomorphologically interpreted. This work can be considered as an example for creating specific landslide susceptibility maps to be used in master planning in order to establish proportional countermeasures to different activation mechanisms. Keywords: statistical analysis, shallow landslide, landslide susceptibility, triggering factors, presence-only approach

Susceptibility of Staphylococcus species and subspecies to fleroxacin.

Science.gov (United States)

Bannerman, T L; Wadiak, D L; Kloos, W E

1991-01-01

Twenty-four Staphylococcus species or subspecies were examined for their susceptibilities to the fluoroquinolone fleroxacin (Ro 23-6240) by disk diffusion (5-micrograms disk) and by agar dilution for the determination of MICs. Resistant strains were further tested for their susceptibilities to oxacillin and the fluoroquinolone ciprofloxacin. Reference strains of the novobiocin-resistant species (Staphylococcus saprophyticus, Staphylococcus cohnii, Staphylococcus xylosus, Staphylococcus arlettae, and Staphylococcus gallinarum) had an intrinsic intermediate susceptibility (MIC, 4 micrograms/ml) to fleroxacin. Fleroxacin resistance was not observed in the reference strains of the novobiocin-susceptible species (MIC, 0.5 to 2.0 micrograms/ml). Clinical isolates of coagulase-negative species were generally less susceptible to fleroxacin than were reference strains. Seven percent of the Staphylococcus epidermidis clinical strains were resistant (MIC, greater than or equal to 8 micrograms/ml) to fleroxacin. Of these strains, 77% were resistant to oxacillin and 50% were resistant to ciprofloxacin. Thirty-four percent of the Staphylococcus haemolyticus clinical strains were resistant to fleroxacin, and 9% had intermediate susceptibility. Of the resistant strains, 95% were resistant to oxacillin and 77% were resistant to ciprofloxacin, while 23% had intermediate susceptibility to ciprofloxacin. Fleroxacin is an effective antimicrobial agent against most staphylococci. PMID:1759838

Grain boundary segregation and intergranular stress corrosion cracking susceptibility of austenitic stainless steels in high temperature water

International Nuclear Information System (INIS)

Shoji, T.; Yamaki, K.; Ballinger, R.G.; Hwang, I.S.

1992-01-01

The effects of grain boundary segregation on intergranular stress corrosion cracking of austenitic stainless steels in high temperature water have been examined as a function of heat treatment. The materials investigated were: (1) two commercial purity Type 304; (2) low sulfur Type 304; (3) nuclear grade Type 304; (4) ultra high purity Type 304L; and (5) Type 316L and Type 347L. Specimens were solution treated at 1050 degrees C for 0.5 hour and given a sensitization heat treatment at 650 degrees C for 50 hours. Some of the specimens were then subjected to an aging heat treatment at 850 degrees C for from one to ten hours to cause Cr recovery at the grain boundaries. The effects of heat treatments on degree of sensitization and grain boundary segregation were evaluated by Electrochemical Potentiokinetic Reactivation (EPR) and Coriou tests, respectively. The susceptibility to stress corrosion (SCC) was evaluated using slow strain rate tests technique (SSRT) in high temperature water. SSRT tests were performed in an aerated pure water (8 ppm dissolved oxygen) at 288 degrees C at a strain rate of 1.33 x 10 -6 /sec. Susceptibility to intergranular stress corrosion cracking was compared with degree of sensitization and grain boundary segregation. The results of the investigation indicate that EPR is not always an accurate indicator of SCC susceptibility. The Coriou test provides a more reliable measure of SCC susceptibility especially for 304L, 304NG, 316L, and 347L stainless steels. The results also indicate that grain boundary segregation as well as degree of sensitization must be considered in the determination of SCC susceptibility

Susceptibility-Weighted Imaging and Quantitative Susceptibility Mapping in the Brain

Science.gov (United States)

Liu, Chunlei; Li, Wei; Tong, Karen A.; Yeom, Kristen W.; Kuzminski, Samuel

2015-01-01

Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) technique that enhances image contrast by using the susceptibility differences between tissues. It is created by combining both magnitude and phase in the gradient echo data. SWI is sensitive to both paramagnetic and diamagnetic substances which generate different phase shift in MRI data. SWI images can be displayed as a minimum intensity projection that provides high resolution delineation of the cerebral venous architecture, a feature that is not available in other MRI techniques. As such, SWI has been widely applied to diagnose various venous abnormalities. SWI is especially sensitive to deoxygenated blood and intracranial mineral deposition and, for that reason, has been applied to image various pathologies including intracranial hemorrhage, traumatic brain injury, stroke, neoplasm, and multiple sclerosis. SWI, however, does not provide quantitative measures of magnetic susceptibility. This limitation is currently being addressed with the development of quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI). While QSM treats susceptibility as isotropic, STI treats susceptibility as generally anisotropic characterized by a tensor quantity. This article reviews the basic principles of SWI, its clinical and research applications, the mechanisms governing brain susceptibility properties, and its practical implementation, with a focus on brain imaging. PMID:25270052

Susceptibility-weighted imaging and quantitative susceptibility mapping in the brain.

Science.gov (United States)

Liu, Chunlei; Li, Wei; Tong, Karen A; Yeom, Kristen W; Kuzminski, Samuel

2015-07-01

Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) technique that enhances image contrast by using the susceptibility differences between tissues. It is created by combining both magnitude and phase in the gradient echo data. SWI is sensitive to both paramagnetic and diamagnetic substances which generate different phase shift in MRI data. SWI images can be displayed as a minimum intensity projection that provides high resolution delineation of the cerebral venous architecture, a feature that is not available in other MRI techniques. As such, SWI has been widely applied to diagnose various venous abnormalities. SWI is especially sensitive to deoxygenated blood and intracranial mineral deposition and, for that reason, has been applied to image various pathologies including intracranial hemorrhage, traumatic brain injury, stroke, neoplasm, and multiple sclerosis. SWI, however, does not provide quantitative measures of magnetic susceptibility. This limitation is currently being addressed with the development of quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI). While QSM treats susceptibility as isotropic, STI treats susceptibility as generally anisotropic characterized by a tensor quantity. This article reviews the basic principles of SWI, its clinical and research applications, the mechanisms governing brain susceptibility properties, and its practical implementation, with a focus on brain imaging. © 2014 Wiley Periodicals, Inc.

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

Science.gov (United States)

2012-01-01

Background The anaerobic spirochetes Brachyspira hyodysenteriae and Brachyspira pilosicoli cause diarrheal diseases in pigs. Their fastidious nature has hampered standardization of methods for antimicrobial susceptibility testing. For monitoring of antimicrobial susceptibility wild type cutoff values are needed to define where the wild type distribution of MICs ends and no approved cutoffs are available for Brachyspira spp. In this study antimicrobial susceptibility data for both species (in total 906 isolates) were compiled and analyzed and wild type cut off values for B. hyodysenteriae proposed. Methods The MICs of tiamulin, valnemulin, tylosin, tylvalosin, doxycycline and lincomycin were determined by broth dilution in brain heart infusion broth supplemented with 10% fetal calf serum. Results The compiled MICs from the broth dilution tests of the B. hyodysenteriae type strain, B78T (ATCC® 27164T), showed that the method yields reproducible results. In an international perspective the frequencies of isolates with decreased antimicrobial susceptibility were low among both B. hyodysenteriae and B. pilosicoli. However, in B. pilosicoli a constant level of 10-15% isolates with tiamulin MICs >4 μg/ml was detected between 2002 and 2010 and in B. hyodysenteriae a gradual increase in tiamulin MICs was seen between 1990 and 2003 although this increase has ceased during the last years. The wild type cutoff values proposed for B. hyodysenteriae are: tiamulin >0.25 μg/ml, valnemulin >0.125 μg/ml, tylosin >16 μg/ml, tylvalosin >1 μg/ml, lincomycin >1 μg/ml and doxycycline >0.5 μg/ml. Conclusions The broth dilution method used in this study has over the years generated tightly grouped MIC populations for the field isolates and reproducible results for the control strain B78T and is therefore a suitable antimicrobial susceptibility test method for monitoring of Brachyspira spp. Here we propose wild type cutoff values for six antimicrobial agents for B. hyodysenteriae

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010

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Pringle Märit

2012-09-01

Full Text Available Abstract Background The anaerobic spirochetes Brachyspira hyodysenteriae and Brachyspira pilosicoli cause diarrheal diseases in pigs. Their fastidious nature has hampered standardization of methods for antimicrobial susceptibility testing. For monitoring of antimicrobial susceptibility wild type cutoff values are needed to define where the wild type distribution of MICs ends and no approved cutoffs are available for Brachyspira spp. In this study antimicrobial susceptibility data for both species (in total 906 isolates were compiled and analyzed and wild type cut off values for B. hyodysenteriae proposed. Methods The MICs of tiamulin, valnemulin, tylosin, tylvalosin, doxycycline and lincomycin were determined by broth dilution in brain heart infusion broth supplemented with 10% fetal calf serum. Results The compiled MICs from the broth dilution tests of the B. hyodysenteriae type strain, B78T (ATCC® 27164T, showed that the method yields reproducible results. In an international perspective the frequencies of isolates with decreased antimicrobial susceptibility were low among both B. hyodysenteriae and B. pilosicoli. However, in B. pilosicoli a constant level of 10-15% isolates with tiamulin MICs >4 μg/ml was detected between 2002 and 2010 and in B. hyodysenteriae a gradual increase in tiamulin MICs was seen between 1990 and 2003 although this increase has ceased during the last years. The wild type cutoff values proposed for B. hyodysenteriae are: tiamulin >0.25 μg/ml, valnemulin >0.125 μg/ml, tylosin >16 μg/ml, tylvalosin >1 μg/ml, lincomycin >1 μg/ml and doxycycline >0.5 μg/ml. Conclusions The broth dilution method used in this study has over the years generated tightly grouped MIC populations for the field isolates and reproducible results for the control strain B78T and is therefore a suitable antimicrobial susceptibility test method for monitoring of Brachyspira spp. Here we propose wild type cutoff values for six antimicrobial

Microbicide excipients can greatly increase susceptibility to genital herpes transmission in the mouse

Directory of Open Access Journals (Sweden)

Sun Mianmian

2010-11-01

Full Text Available Abstract Background Several active ingredients proposed as vaginal microbicides have been shown paradoxically to increase susceptibility to infection in mouse genital herpes (HSV-2 vaginal susceptibility models and in clinical trials. In addition, "inactive ingredients" (or excipients used in topical products to formulate and deliver the active ingredient might also cause epithelial toxicities that increase viral susceptibility. However, excipients have not previously been tested in susceptibility models. Methods Excipients commonly used in topical products were formulated in a non-toxic vehicle (the "HEC universal placebo", or other formulations as specified. Twelve hours after exposure to the excipient or a control treatment, mice were challenged with a vaginal dose of HSV-2, and three days later were assessed for infection by vaginal lavage culture to assess susceptibility. Results The following excipients markedly increased susceptibility to HSV-2 after a single exposure: 5% glycerol monolaurate (GML formulated in K-Y® Warming Jelly, 5% GML as a colloidal suspension in phosphate buffered saline, K-Y Warming Jelly alone, and both of its humectant/solvent ingredients (neat propylene glycol and neat PEG-8. For excipients formulated in the HEC vehicle, 30% glycerin significantly increased susceptibility, and a trend toward increased HSV-2 susceptibility was observed after 10% glycerin, and 0.1% disodium EDTA, but not after 0.0186% disodium EDTA. The following excipients did not increase susceptibility: 10% propylene glycol, 0.18%, methylparaben plus 0.02% propylparaben, and 1% benzyl alcohol. Conclusions As reported with other surfactants, the surfactant/emulsifier GML markedly increased susceptibility to HSV-2. Glycerin at 30% significantly increased susceptibility, and, undiluted propylene glycol and PEG-8 greatly increased susceptibility.

Abundance and antibiotic susceptibility of Vibrio spp. isolated from microplastics

Science.gov (United States)

Laverty, A. L.; Darr, K.; Dobbs, F. C.

2016-02-01

In recent years, there has been a growing concern for `microplastics' (particles pieces, paired seawater samples, and from them cultured 44 putative Vibrio spp. isolates, 18 of which were PCR-confirmed as V. parahaemolyticus and 3 as V. vulnificus. There were no PCR-confirmed V. cholerae isolates. We used the Kirby-Bauer disk diffusion susceptibility test to examine the isolates' response to six antibiotics: chloramphenicol (30μg), gentamicin (10μg), ampicillin (10μg), streptomycin (10μg), tetracycline (30μg), and rifampin (5μg). Vibrio isolates were susceptible to three or more of the six antibiotics tested and all were susceptible to tetracycline and chloramphenicol. There were no apparent differences between the antibiotic susceptibilities of vibrios isolated from microplastics compared to those from the water column. In every instance tested, vibrios on microplastics were enriched by at least two orders of magnitude compared to those from paired seawater samples. This study demonstrates that microplastic particles serve as a habitat for Vibrio species, in particular V. vulnificus and V. parahaemolyticus, confirming the conjecture of Zettler et al. (2013) that plastics may serve as a vector for these and other potentially pathogenic bacteria.

Susceptibility of Eikenella corrodens to Newer Beta-Lactam Antibiotics

OpenAIRE

1981-01-01

In vitro susceptibility testing of 28 strains of Eikenella corrodens by the agar dilution technique showed that all strains were uniformly susceptible to penicillin, ticarcillin, cefoxitin, cefotaxime, N-formimidoyl thienamycin, and moxalactam and resistant to clindamycin and cefadroxil. Cefoperazone, piperacillin, and mezlocillin showed good activity, with some strains relatively resistant. Bacampicillin and cefamandole showed relatively poor activity.

Comparison between E-test and CLSI broth microdilution method for antifungal susceptibility testing of Candida albicans oral isolates Comparação entre E-test e o método da microdiluição do CLSI para teste de susceptibilidade a antifúngicos de isolados orais de Candida albicans

Directory of Open Access Journals (Sweden)

Cristiane Yumi Koga-Ito

2008-02-01

Full Text Available Thirty Candida albicans isolated from oral candidosis patients and 30 C. albicans isolated from control individuals were studied. In vitro susceptibility tests were performed for amphotericin B, fluconazole, 5-flucytosine and itraconazole through the Clinical and Laboratorial Standards Institute (CLSI reference method and E test system. The results obtained were analyzed and compared. MIC values were similar for the strains isolated from oral candidosis patients and control individuals. The agreement rate for the two methods was 66.67% for amphotericin B, 53.33% for fluconazole, 65% for flucytosine and 45% for itraconazole. According to our data, E test method could be an alternative to trial routine susceptibility testing due to its simplicity. However, it can not be considered a substitute for the CLSI reference method.Trinta Candida albicans isoladas de pacientes portadores de candidose oral e 30 Candida albicans isoladas de indivíduos controle foram estudadas. Testes de susceptibilidade in vitro foram realizados com anfotericina B, fluconazol, 5-flucitosina e itraconazol pelo método do Clinical and Laboratorial Standars Institute (CLSI e por E-test. Os resultados obtidos foram analisados e comparados. Os valores de CIM foram semelhantes para amostras isoladas de pacientes portadores de candidose oral e indivíduos controle. A concordância entre os dois métodos foi de 66,7% para a anfotericina B, 53,33% para o fluconazol, 65% para a flucitosina e 45% para o itraconazol. De acordo com estes resultados, o método do E-test poderia ser uma alternativa para a triagem de casos de rotina pela sua simplicidade. Entretanto, este método não pode ser considerado como um substituto para o método de referência do CLSI.

Grey matter correlates of susceptibility to scams in community-dwelling older adults.

Science.gov (United States)

Duke Han, S; Boyle, Patricia A; Yu, Lei; Arfanakis, Konstantinos; James, Bryan D; Fleischman, Debra A; Bennett, David A

2016-06-01

Susceptibility to scams is a significant issue among older adults, even among those with intact cognition. Age-related changes in brain macrostructure may be associated with susceptibility to scams; however, this has yet to be explored. Based on previous work implicating frontal and temporal lobe functioning as important in decision making, we tested the hypothesis that susceptibility to scams is associated with smaller grey matter volume in frontal and temporal lobe regions in a large community-dwelling cohort of non-demented older adults. Participants (N = 327, mean age = 81.55, mean education = 15.30, 78.9 % female) completed a self-report measure used to assess susceptibility to scams and an MRI brain scan. Results indicated an inverse association between overall grey matter and susceptibility to scams in models adjusted for age, education, and sex; and in models further adjusted for cognitive function. No significant associations were observed for white matter, cerebrospinal fluid, or total brain volume. Models adjusted for age, education, and sex revealed seven clusters showing smaller grey matter in the right parahippocampal/hippocampal/fusiform, left middle temporal, left orbitofrontal, right ventromedial prefrontal, right middle temporal, right precuneus, and right dorsolateral prefrontal regions. In models further adjusted for cognitive function, results revealed three significant clusters showing smaller grey matter in the right parahippocampal/hippocampal/fusiform, right hippocampal, and right middle temporal regions. Lower grey matter concentration in specific brain regions may be associated with susceptibility to scams, even after adjusting for cognitive ability. Future research is needed to determine whether grey matter reductions in these regions may be a biomarker for susceptibility to scams in old age.

original article antimicrobial susceptibility pattern of lactic acid

African Journals Online (AJOL)

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All the 57 tested lactic acid bacteria isolates were sensitive to Pencillin G (Pen, 10units), and ... resistance genes for Penicillin G and Erythromycin as indicated by the sensitivity of isolates. .... Antibiotic Susceptibility Test: The LAB isolates were ...

The role of epidemiological cutoff values (ECVs/ECOFFs) in antifungal susceptibility testing and interpretation for uncommon yeasts and moulds.

Science.gov (United States)

Espinel-Ingroff, Ana; Turnidge, John

2016-01-01

The role of antimicrobial susceptibility testing is to aid in selecting the best agent for the treatment of bacterial and fungal diseases. This has been best achieved by the setting of breakpoints by Clinical Laboratory Standards Institute (CLSI) for prevalent Candida spp. versus anidulafungin, caspofungin, micafungin, fluconazole, and voriconazole. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) also has set breakpoints for prevalent and common Candida and Aspergillus species versus amphotericin B, itraconazole, and posaconazole. Recently, another interpretive category, the epidemiological cut off value, could aid in the early identification of strains with acquired resistance mechanisms. CLSI has postulated that epidemiological cut off values may, with due caution, aid physicians in managing mycosis by species where breakpoints are not available. This review provides (1) the criteria and statistical approach to establishing and estimating epidemiological cut off values (ECVs), (2) the role of the epidemiological cut off value in establishing breakpoints, (3) the potential role of epidemiological cut off values in clinical practice, (4) and the wide range of CLSI-based epidemiological cut off values reported in the literature as well as EUCAST and Sensititre Yeast One-ECVs. Additionally, we provide MIC/MEC (minimal inhibitory concentrations/minimum effective concentrations) ranges/modes of each pooled distribution used for epidemiological cut off value calculation. We focus on the epidemiological cut off value, the new interpretive endpoint that will identify the non-wild type strains (defined as potentially harboring resistance mechanisms). However, we emphasize that epidemiological cut off values will not categorize a fungal isolate as susceptible or resistant as breakpoints do, because the former do not account for the pharmacology of the antifungal agent or the findings from clinical outcome studies. Copyright © 2016 Asociación Espa

Topological susceptibility from slabs

Energy Technology Data Exchange (ETDEWEB)

Bietenholz, Wolfgang [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A.P. 70-543, Distrito Federal, C.P. 04510 (Mexico); Forcrand, Philippe de [Institute for Theoretical Physics, ETH Zürich,CH-8093 Zürich (Switzerland); CERN, Physics Department, TH Unit, CH-1211 Geneva 23 (Switzerland); Gerber, Urs [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A.P. 70-543, Distrito Federal, C.P. 04510 (Mexico); Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo,Edificio C-3, Apdo. Postal 2-82, Morelia, Michoacán, C.P. 58040 (Mexico)

2015-12-14

In quantum field theories with topological sectors, a non-perturbative quantity of interest is the topological susceptibility χ{sub t}. In principle it seems straightforward to measure χ{sub t} by means of Monte Carlo simulations. However, for local update algorithms and fine lattice spacings, this tends to be difficult, since the Monte Carlo history rarely changes the topological sector. Here we test a method to measure χ{sub t} even if data from only one sector are available. It is based on the topological charges in sub-volumes, which we denote as slabs. Assuming a Gaussian distribution of these charges, this method enables the evaluation of χ{sub t}, as we demonstrate with numerical results for non-linear σ-models.

Ciprofloxacin susceptibility of Pseudomonas aeruginosa isolates from keratitis

DEFF Research Database (Denmark)

Lomholt, JA; Kilian, Mogens

2003-01-01

keratitis, endophthalmitis, contact lens associated red eye (CLARE), and contact lens storage cases showed MIC values below 1 mg/l. Several allelic forms of gyrA and a single variation in the mexR gene product were detected in 10 ciprofloxacin susceptible strains. CONCLUSIONS: The vast majority of eye......AIM: To examine the ciprofloxacin susceptibility of 106 Pseudomonas aeruginosa eye isolates from the United Kingdom, Denmark, India, the United States, and Australia, and to determine the molecular mechanisms of resistance. METHODS: Ciprofloxacin susceptibility was tested by an agar dilution method...... isolates of P aeruginosa from European countries are fully susceptible to ciprofloxacin and the concentration of ciprofloxacin eye drops used for local treatment (3000 mg/l) exceeds MIC values for strains recorded as resistant. Mutations in more than one target gene were associated with higher MIC values....

Ciprofloxacin susceptibility of Pseudomonas aeruginosa isolates from keratitis

DEFF Research Database (Denmark)

Lomholt, JA; Kilian, Mogens

2003-01-01

AIM: To examine the ciprofloxacin susceptibility of 106 Pseudomonas aeruginosa eye isolates from the United Kingdom, Denmark, India, the United States, and Australia, and to determine the molecular mechanisms of resistance. METHODS: Ciprofloxacin susceptibility was tested by an agar dilution method...... keratitis, endophthalmitis, contact lens associated red eye (CLARE), and contact lens storage cases showed MIC values below 1 mg/l. Several allelic forms of gyrA and a single variation in the mexR gene product were detected in 10 ciprofloxacin susceptible strains. CONCLUSIONS: The vast majority of eye...... isolates of P aeruginosa from European countries are fully susceptible to ciprofloxacin and the concentration of ciprofloxacin eye drops used for local treatment (3000 mg/l) exceeds MIC values for strains recorded as resistant. Mutations in more than one target gene were associated with higher MIC values....

Susceptibility of ternary aluminum alloys to cracking during solidification

International Nuclear Information System (INIS)

Liu, Jiangwei; Kou, Sindo

2017-01-01

The crack susceptibility map of a ternary Al alloy system provides useful information about which alloy compositions are most susceptible to cracking and thus should be avoided by using a filler metal with a significantly different composition. In the present study the crack susceptibility maps of ternary Al alloy systems were calculated based on the maximum |dT/d(f S ) 1/2 | as an index for the crack susceptibility, where T is temperature and f S fraction solid. Due to the complexity associated with ternary alloy solidification, commercial thermodynamic software Pandat and Al database PanAluminum, instead of analytical equations, were used to calculate f S as a function of T and hence the maximum |dT/d(f S ) 1/2 | for ternary Al-Mg-Si, Al-Cu-Mg and Al-Cu-Si alloy systems. A crack susceptibility map covering 121 alloy compositions was constructed for each of the three ternary alloy systems at each of the following three levels of back diffusion: no back diffusion, back diffusion under a 100 °C/s cooling rate, and back diffusion under 20° C/s. The location of the region of high crack susceptibility, which is the most important part of the map, was shown in each of the nine calculated maps. These locations were compared with those observed in crack susceptibility tests by previous investigators. With back diffusion considered, either under 20 or 100 °C/s, the agreement between the calculated and observed maps was good especially for Al-Mg-Si and Al-Cu-Mg. Thus, the maximum |dT/d(f S ) 1/2 | can be used as a crack susceptibility index to construct crack susceptibility maps for ternary Al alloys and to evaluate the effect of back diffusion on their crack susceptibility. - Graphical abstract: The crack susceptibility map of a ternary alloy system indicates the composition range most susceptible to cracking, which should be avoided in welding or casting. The crack susceptibility maps of ternary Al alloy systems Al-Mg-Si, Al-Cu-Mg and Al-Cu-Si were calculated based

Susceptibility of various cell lines to Neospora caninum tachyzoites cultivation

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Khordadmehr, M.,

2014-05-01

Full Text Available Neospora caninum is a coccidian protozoan parasite which is a major cause of bovine abortions and neonatal mortality in cattle, sheep, goat and horse. Occasionally, cultured cells are used for isolation and multiplication of the agent in vitro with several purposes. In this study the tachyzoite yields of N. caninum were compared in various cell cultures as the host cell lines. Among the cell cultures tested, two presented good susceptibility to the agent: cell lines Vero and MA-104. SW742 and TLI (in vitro suspension culture of lymphoid cells infected with Theileria lestoquardi showed moderate sensitivity. No viable tachyzoite were detected in the culture of MDCK and McCoy cell lines. These results demonstrate that MA-104 and SW742 cells present adequate susceptibility to N. caninum compared to Vero cells, which have been largely used to multiply the parasite in vitro. Moreover, these have easy manipulation, fast multiplication and relatively low nutritional requirements. In addition, the result of this study showed that TLI cell line as a suspension cell culture is susceptible to Nc-1 tachyzoites infection and could be used as an alternative host cell line for tachyzoites culture in vitro studies.

Antimicrobial Susceptibility Monitoring of Bacterial Pathogens Isolated from Urinary Tract Infections in Dogs and Cats Across Europe: ComPath Results.

Science.gov (United States)

Moyaert, Hilde; Morrissey, Ian; de Jong, Anno; El Garch, Farid; Klein, Ulrich; Ludwig, Carolin; Thiry, Julien; Youala, Myriam

2017-04-01

ComPath is a pan-European antimicrobial surveillance program collecting bacterial pathogens from dogs and cats not recently exposed to antimicrobials. We present minimum inhibitory concentration data obtained using Clinical and Laboratory Standards Institute methodology for 616 urinary tract infection (UTI) isolates collected between 2008 and 2010. In both dogs and cats, the most common pathogen was Escherichia coli (59.8% and 46.7%, respectively). Antimicrobial activity against E. coli in dogs and cats was similar with fluoroquinolone and trimethoprim/sulfamethoxazole susceptibility >90%. Ampicillin susceptibility was ∼80%. Staphylococcus intermedius Group isolates from dogs (67/437, 15.3%) had high antimicrobial susceptibility (>90%) toward beta-lactams, fluoroquinolones, and trimethoprim/sulfamethoxazole. Four canine isolates (6%) were oxacillin resistant, and harbored mecA. Proteus mirabilis from dogs (48/437, 11.0%) had high antimicrobial susceptibility (∼90%) to amoxicillin/clavulanic acid, enrofloxacin, and marbofloxacin and slightly lower susceptibility (∼80-85%) to ampicillin and orbifloxacin. Streptococcus canis isolates (35/437, 8.0%) from dogs were all susceptible to ampicillin and amoxicillin/clavulanic acid and >90% susceptible to marbofloxacin. Although resistance was not observed, high intermediate susceptibility was seen for both enrofloxacin (28.6%) and orbifloxacin (85.7%). Overall, antimicrobial in vitro activity appears to be high in UTI pathogens from dogs and cats with low multidrug resistance, although a lack of specific dog and cat breakpoints for important antimicrobials such as cefovecin, cephalexin, and ibafloxacin prevents analysis of susceptibility for these agents.

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.

A multi-annual landslide inventory for the assessment of shallow landslide susceptibility - Two test cases in Vorarlberg, Austria

Science.gov (United States)

Zieher, Thomas; Perzl, Frank; Rössel, Monika; Rutzinger, Martin; Meißl, Gertraud; Markart, Gerhard; Geitner, Clemens

2016-04-01

Geomorphological landslide inventories provide crucial input data for any study on the assessment of landslide susceptibility, hazard or risk. Several approaches for assessing landslide susceptibility have been proposed to identify areas particularly vulnerable to this natural hazard. What they have in common is the need for data of observed landslides. Therefore the first step of any study on landslide susceptibility is usually the compilation of a geomorphological landslide inventory using a geographical information system. Recent research has proved the feasibility of orthophoto interpretation for the preparation of an inventory aimed at the delineation of landslides with the use of distinctive signs in the imagery data. In this study a multi-annual landslide inventory focusing on shallow landslides (i.e. translational soil slides of 0-2 m in depth) was compiled for two study areas in Vorarlberg (Austria) from the interpretation of nine orthophoto series. In addition, derivatives of two generations of airborne laser scanning data aided the mapping procedure. Landslide scar areas were delineated on the basis of a high-resolution differential digital terrain model. The derivation of landslide volumes, depths and depth-to-length ratios are discussed. Results show that most mapped landslides meet the definition of a shallow landslide. The inventory therefore provides the data basis for the assessment of shallow landslide susceptibility and allows for the application of various modelling techniques.

Activity of pradofloxacin against Porphyromonas and Prevotella spp. Implicated in periodontal disease in dogs: susceptibility test data from a European multicenter study.

Science.gov (United States)

Stephan, Bernd; Greife, Heinrich A; Pridmore, Andrew; Silley, Peter

2008-06-01

Collaborating veterinarians from five European countries collected subgingival bacterial samples from dogs exhibiting clinical periodontal disease. Sterile endodontic paper points were used for collection of the samples, which were transported to a central laboratory for susceptibility testing. Anaerobic bacteria were isolated and Porphyromonas and Prevotella isolates identified to the species level; susceptibility to pradofloxacin and metronidazole was determined using the CLSI agar dilution methodology. A total of 630 isolates, 310 of Porphyromonas spp. and 320 of Prevotella spp., were isolated. Pradofloxacin MIC data for all isolates were in the range of periodontal disease and shows activity against metronidazole-resistant isolates. The broad-spectrum activity of pradofloxacin makes it a suitable candidate for the treatment of periodontal disease in dogs.

Susceptibility to chemical insecticides of two Brazilian populations of the visceral leishmaniasis vector Lutzomyia longipalpis (Diptera: Psychodidae).

Science.gov (United States)

Alexander, B; Barros, V C; de Souza, S F; Barros, S S; Teodoro, L P; Soares, Z R; Gontijo, N F; Reithinger, R

2009-10-01

To investigate the insecticide susceptibility of two geographically separated Lutzomyia longipalpis populations (Lapinha and Montes Claros) with different histories of insecticide exposure (i.e. no exposure and repeated exposure, respectively). (i) Bioassay monitoring of sand fly survival over time when exposed to a range of insecticides; and (ii) analysis of the level of insecticide detoxification enzymes in individual sand flies caught at both study sites. Insecticides tested were the organophosphates malathion and fenitrothion and the pyrethroids lambda-cyhalothrin, permethrin and deltamethrin. Survival analyses showed that whilst there was no overall significant difference in susceptibility of both populations to organophosphates, Lapinha sand flies were significantly more susceptible to pyrethroids than those from Montes Claros. Multiple regression analyses also showed that insecticide susceptibility in both locations varied with sand fly sex. The relative susceptibilities of the two sand fly populations to tested insecticides were also compared. Thus, Montes Claros sand flies were most susceptible to malathion, followed by fenitrothion, deltamethrin and permethrin. Those from Lapinha were most susceptible to lambda-cyhalothrin, followed by malathion, permethrin, deltamethrin and fenitrothion. Biochemical analyses demonstrated that Montes Claros sand flies had significantly lower insecticide detoxification enzyme activity than Lapinha sand flies. Our results are the first record of significantly reduced susceptibility to the insecticides used in control of wild populations of Lu. longipalpis. They demonstrate the importance of evaluating chemicals against this species by conventional bioassay and microplate assays before and during spraying programmes.

Quantitative Susceptibility Mapping: Contrast Mechanisms and Clinical Applications

Science.gov (United States)

Liu, Chunlei; Wei, Hongjiang; Gong, Nan-Jie; Cronin, Matthew; Dibb, Russel; Decker, Kyle

2016-01-01

Quantitative susceptibility mapping (QSM) is a recently developed MRI technique for quantifying the spatial distribution of magnetic susceptibility within biological tissues. It first uses the frequency shift in the MRI signal to map the magnetic field profile within the tissue. The resulting field map is then used to determine the spatial distribution of the underlying magnetic susceptibility by solving an inverse problem. The solution is achieved by deconvolving the field map with a dipole field, under the assumption that the magnetic field is a result of the superposition of the dipole fields generated by all voxels and that each voxel has its unique magnetic susceptibility. QSM provides improved contrast to noise ratio for certain tissues and structures compared to its magnitude counterpart. More importantly, magnetic susceptibility is a direct reflection of the molecular composition and cellular architecture of the tissue. Consequently, by quantifying magnetic susceptibility, QSM is becoming a quantitative imaging approach for characterizing normal and pathological tissue properties. This article reviews the mechanism generating susceptibility contrast within tissues and some associated applications. PMID:26844301

Species distribution & antifungal susceptibility pattern of oropharyngeal Candida isolates from human immunodeficiency virus infected individuals

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Partha Pratim Das

2016-01-01

Results: From the 59 culture positive HIV seropositive cases, 61 Candida isolates were recovered; Candidaalbicans (n=47, 77.0%, C. dubliniensis (n=9, 14.7%, C. parapsilosis (n=2, 3.2%, C. glabrata (n=2, 3.2%, and C. famata (n=1, 1.6%. Candida colonization in HIV-seropositive individuals was significantly higher than that of HIV-seronegative (control group. Antifungal susceptibility testing revealed (n=6, 9.3% C. albicans isolates resistant to voriconazole and fluconazole by disk-diffusion method whereas no resistance was seen by Fungitest method. Interpretation & conclusions: C. albicans was the commonest Candida species infecting or colonizing HIV seropositive individuals. Oropharyngeal Candida isolates had high level susceptibility to all the major antifungals commonly in use. Increased level of immunosuppression in HIV-seropositives and drug resistance of non-albicans Candida species makes identification and susceptibility testing of Candida species necessary in different geographical areas of the country.

Genetic susceptibility markers for a breast-colorectal cancer phenotype: Exploratory results from genome-wide association studies

Science.gov (United States)

Joon, Aron; Brewster, Abenaa M.; Chen, Wei V.; Eng, Cathy; Shete, Sanjay; Casey, Graham; Schumacher, Fredrick; Lin, Yi; Harrison, Tabitha A.; White, Emily; Ahsan, Habibul; Andrulis, Irene L.; Whittemore, Alice S.; Ko Win, Aung; Schmidt, Daniel F.; Kapuscinski, Miroslaw K.; Ochs-Balcom, Heather M.; Gallinger, Steven; Jenkins, Mark A.; Newcomb, Polly A.; Lindor, Noralane M.; Peters, Ulrike; Amos, Christopher I.; Lynch, Patrick M.

2018-01-01

Background Clustering of breast and colorectal cancer has been observed within some families and cannot be explained by chance or known high-risk mutations in major susceptibility genes. Potential shared genetic susceptibility between breast and colorectal cancer, not explained by high-penetrance genes, has been postulated. We hypothesized that yet undiscovered genetic variants predispose to a breast-colorectal cancer phenotype. Methods To identify variants associated with a breast-colorectal cancer phenotype, we analyzed genome-wide association study (GWAS) data from cases and controls that met the following criteria: cases (n = 985) were women with breast cancer who had one or more first- or second-degree relatives with colorectal cancer, men/women with colorectal cancer who had one or more first- or second-degree relatives with breast cancer, and women diagnosed with both breast and colorectal cancer. Controls (n = 1769), were unrelated, breast and colorectal cancer-free, and age- and sex- frequency-matched to cases. After imputation, 6,220,060 variants were analyzed using the discovery set and variants associated with the breast-colorectal cancer phenotype at Pcolorectal cancer phenotype in the discovery and replication data (most significant; rs7430339, Pdiscovery = 1.2E-04; rs7429100, Preplication = 2.8E-03). In meta-analysis of the discovery and replication data, the most significant association remained at rs7429100 (P = 1.84E-06). Conclusion The results of this exploratory analysis did not find clear evidence for a susceptibility locus with a pleiotropic effect on hereditary breast and colorectal cancer risk, although the suggestive association of genetic variation in the region of ROBO1, a potential tumor suppressor gene, merits further investigation. PMID:29698419

Molecular identification and amphotericin B susceptibility testing of clinical isolates of Aspergillus from 11 hospitals in Korea.

Science.gov (United States)

Heo, Min Seok; Shin, Jong Hee; Choi, Min Ji; Park, Yeon Joon; Lee, Hye Soo; Koo, Sun Hoe; Lee, Won Gil; Kim, Soo Hyun; Shin, Myung Geun; Suh, Soon Pal; Ryang, Dong Wook

2015-11-01

We investigated the species distribution and amphotericin B (AMB) susceptibility of Korean clinical Aspergillus isolates by using two Etests and the CLSI broth microdilution method. A total of 136 Aspergillus isolates obtained from 11 university hospitals were identified by sequencing the internal transcribed spacer (ITS) and β-tubulin genomic regions. Minimal inhibitory concentrations (MICs) of AMB were determined in Etests using Mueller-Hinton agar (Etest-MH) and RPMI agar (Etest-RPG), and categorical agreement with the CLSI method was assessed by using epidemiological cutoff values. ITS sequencing identified the following six Aspergillus species complexes: Aspergillus fumigatus (42.6% of the isolates), A. niger (23.5%), A. flavus (17.6%), A. terreus (11.0%), A. versicolor (4.4%), and A. ustus (0.7%). Cryptic species identifiable by β-tubulin sequencing accounted for 25.7% (35/136) of the isolates. Of all 136 isolates, 36 (26.5%) had AMB MICs of ≥2 μg/mL by the CLSI method. The categorical agreement of Etest-RPG with the CLSI method was 98% for the A. fumigatus, A. niger, and A. versicolor complexes, 87% for the A. terreus complex, and 37.5% for the A. flavus complex. That of Etest-MH was ≤75% for the A. niger, A. flavus, A. terreus, and A. versicolor complexes but was higher for the A. fumigatus complex (98.3%). Aspergillus species other than A. fumigatus constitute about 60% of clinical Aspergillus isolates, and reduced AMB susceptibility is common among clinical isolates of Aspergillus in Korea. Molecular identification and AMB susceptibility testing by Etest-RPG may be useful for characterizing Aspergillus isolates of clinical relevance.

[Susceptibility of enterococci to natural and synthetic iron chelators].

Science.gov (United States)

Lisiecki, Paweł; Mikucki, Jerzy

2002-01-01

A total of 79 strains of enterococci belonging to 10 species were tested for susceptibility to natural and synthetic iron chelators. All strains produced siderophores. These enterococci were susceptible to three synthetic iron chelators only: 8-hydroxyquinoline, disodium versenate (EDTA) and o-phenanthroline. They were resistant to all other synthetic chelators: ethylenediamine-di(o-hydroxyphenylacetic acid) (EDDHA), nitrilotriacetate, 2,2'-bipiridyl, salicylic acid, 8-hydroxy-5-sulphonic acid and to all natural chelators: ovotransferrine, human apotransferrine, horse apoferritine, desferrioxamine B, ferrichrome and rhodotorulic acid. The relations between susceptibility/resistance, iron assimilation and structure and stability constants of iron chelators were discussed.

Antifungal Susceptibility Testing of Aspergillus spp. by Using a Composite Correlation Index (CCI)-Based Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Method Appears To Not Offer Benefit over Traditional Broth Microdilution Testing.

Science.gov (United States)

Gitman, Melissa R; McTaggart, Lisa; Spinato, Joanna; Poopalarajah, Rahgavi; Lister, Erin; Husain, Shahid; Kus, Julianne V

2017-07-01

Aspergillus spp. cause serious invasive lung infections, and Aspergillus fumigatus is the most commonly encountered clinically significant species. Voriconazole is considered to be the drug of choice for treating A. fumigatus infections; however, rising resistance rates have been reported. We evaluated a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based method for the differentiation between wild-type and non-wild-type isolates of 20 Aspergillus spp. (including 2 isolates of Aspergillus ustus and 1 of Aspergillus calidoustus that were used as controls due their intrinsic low azole susceptibility with respect to the in vitro response to voriconazole). At 30 and 48 h of incubation, there was complete agreement between Cyp51A sequence analysis, broth microdilution, and MALDI-TOF MS classification of isolates as wild type or non-wild type. In this proof-of-concept study, we demonstrated that MALDI-TOF MS can be used to accurately detect A. fumigatus strains with reduced voriconazole susceptibility. However, rather than proving to be a rapid and simple method for antifungal susceptibility testing, this particular MS-based method showed no benefit over conventional testing methods. © Crown copyright 2017.

Antifungal Susceptibility Testing of Aspergillus spp. by Using a Composite Correlation Index (CCI)-Based Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Method Appears To Not Offer Benefit over Traditional Broth Microdilution Testing

Science.gov (United States)

Gitman, Melissa R.; McTaggart, Lisa; Spinato, Joanna; Poopalarajah, Rahgavi; Lister, Erin; Husain, Shahid

2017-01-01

ABSTRACT Aspergillus spp. cause serious invasive lung infections, and Aspergillus fumigatus is the most commonly encountered clinically significant species. Voriconazole is considered to be the drug of choice for treating A. fumigatus infections; however, rising resistance rates have been reported. We evaluated a matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based method for the differentiation between wild-type and non-wild-type isolates of 20 Aspergillus spp. (including 2 isolates of Aspergillus ustus and 1 of Aspergillus calidoustus that were used as controls due their intrinsic low azole susceptibility with respect to the in vitro response to voriconazole). At 30 and 48 h of incubation, there was complete agreement between Cyp51A sequence analysis, broth microdilution, and MALDI-TOF MS classification of isolates as wild type or non-wild type. In this proof-of-concept study, we demonstrated that MALDI-TOF MS can be used to accurately detect A. fumigatus strains with reduced voriconazole susceptibility. However, rather than proving to be a rapid and simple method for antifungal susceptibility testing, this particular MS-based method showed no benefit over conventional testing methods. PMID:28404678

Frost heave susceptibility of saturated soil under constant rate of freezing

Science.gov (United States)

Ryokai, K.; Iguro, M.; Yoneyama, K.

Introduced are the results of experiments carried out to quantitatively obtain the frost heave pressure and displacement of soil subjected to artificial freezing or freezing around in-ground liquefied natural gas storage tanks. This experiment is conducted to evaluate the frost heave susceptibility of saturated soil under overconsolidation. In other words, this experiment was carried out to obtain the relation of the over-burden pressure and freezing rate to the frost heave ratio by observing the frost heave displacement and freezing time of specimens by freezing the specimens at a constant freezing rate under a constant overburden pressure, while letting water freely flow in and out of the system. Introduced are the procedures for frost heave test required to quantitatively obtain the frost heave displacement and pressure of soil. Furthermore, the relation between the frost heave susceptibility and physical properties of soil obtained by this test is reported.

CISH and susceptibility to infectious diseases.

Science.gov (United States)

Khor, Chiea C; Vannberg, Fredrik O; Chapman, Stephen J; Guo, Haiyan; Wong, Sunny H; Walley, Andrew J; Vukcevic, Damjan; Rautanen, Anna; Mills, Tara C; Chang, Kwok-Chiu; Kam, Kai-Man; Crampin, Amelia C; Ngwira, Bagrey; Leung, Chi-Chiu; Tam, Cheuk-Ming; Chan, Chiu-Yeung; Sung, Joseph J Y; Yew, Wing-Wai; Toh, Kai-Yee; Tay, Stacey K H; Kwiatkowski, Dominic; Lienhardt, Christian; Hien, Tran-Tinh; Day, Nicholas P; Peshu, Nobert; Marsh, Kevin; Maitland, Kathryn; Scott, J Anthony; Williams, Thomas N; Berkley, James A; Floyd, Sian; Tang, Nelson L S; Fine, Paul E M; Goh, Denise L M; Hill, Adrian V S

2010-06-03

The interleukin-2-mediated immune response is critical for host defense against infectious pathogens. Cytokine-inducible SRC homology 2 (SH2) domain protein (CISH), a suppressor of cytokine signaling, controls interleukin-2 signaling. Using a case-control design, we tested for an association between CISH polymorphisms and susceptibility to major infectious diseases (bacteremia, tuberculosis, and severe malaria) in blood samples from 8402 persons in Gambia, Hong Kong, Kenya, Malawi, and Vietnam. We had previously tested 20 other immune-related genes in one or more of these sample collections. We observed associations between variant alleles of multiple CISH polymorphisms and increased susceptibility to each infectious disease in each of the study populations. When all five single-nucleotide polymorphisms (SNPs) (at positions -639, -292, -163, +1320, and +3415 [all relative to CISH]) within the CISH-associated locus were considered together in a multiple-SNP score, we found an association between CISH genetic variants and susceptibility to bacteremia, malaria, and tuberculosis (P=3.8x10(-11) for all comparisons), with -292 accounting for most of the association signal (P=4.58x10(-7)). Peripheral-blood mononuclear cells obtained from adult subjects carrying the -292 variant, as compared with wild-type cells, showed a muted response to the stimulation of interleukin-2 production--that is, 25 to 40% less CISH expression. Variants of CISH are associated with susceptibility to diseases caused by diverse infectious pathogens, suggesting that negative regulators of cytokine signaling have a role in immunity against various infectious diseases. The overall risk of one of these infectious diseases was increased by at least 18% among persons carrying the variant CISH alleles. 2010 Massachusetts Medical Society

Increasing rate of daptomycin non-susceptible strains of Staphylococcus aureus in patients with atopic dermatitis

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Izabela Błażewicz

2017-12-01

Full Text Available Introduction : Daptomycin is a cyclic lipopeptide that is bactericidal against Staphylococcus aureus , including methicillin-resistant S. aureus (MRSA, vancomycin-intermediate S. aureus (VISA and vancomycin-resistant S. aureus (VRSA strains. Daptomycin exerts its antimicrobial effect by a calcium-dependent interaction with the cytoplasmic membrane resulting in depolarization, ion loss and rapid cell death. Unfortunately, loss of daptomycin susceptibility in S. aureus in the clinical setting has been noted. Aim : To evaluate the susceptibility profile to daptomycin among S. aureus strains isloted from patients with atopic dermatitis (AD. Another point was to correlate the results obtained by broth microdilution method and Etest, which is commonly applied in clinical setting. Material and methods : One hundred patients with the diagnosis of atopic dermatitis were microbiologically assessed for the carriage of S. aureus . Antimicrobial susceptibility tests were performed using broth-microdilution (BMD and Etests for daptomycin. Results : Staphylococcus aureus strains were isolated from the majority of our patients, either from the skin (73% or the anterior nares (75%. Six of the 100 nasal swabs (6% and 5 of the 100 skin swabs (5% were positive for methicillin-resistant Staphylococcus aureus (MRSA. A total of 81 of 148 (54.7% daptomycin non-susceptible isolates of S. aureus were identified by BMD. Only 19 of 81 were also classified as non-susceptible by Etest. Conclusions : Clinicians and microbiologists should be aware of the possibility of the emergence of daptomycin non-susceptibility (or increase in minimal inhibitory concentration during prolonged therapy and closely monitor the susceptibility of persisting isolates that might be recovered during therapy.

Antibacterial susceptibility patterns of Porphyromonas gingivalis isolated from chronic periodontitis patients.

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Japoni, Aziz; Vasin, Afsaneh; Noushadi, Sadighah; Kiany, Farin; Japoni, Sara; Alborzi, Abdolvahab

2011-11-01

To test the antimicrobial sensitivity of Porphyromonas gingivalis to a panel of eight orally administrable antibiotics in chronic periodontal diseases and to evaluate factors associated with periodontitis in adult patients. A total of fifty strains of P. gingivalis were isolated from one hundred and twenty adult patients with chronic perio-dontitis. Identification of bacteria was carried out by anaerobic culture and biochemical tests. Selected colonies of P. gingivalis were used to evaluate the antibacterial activities of penicillin, metronidazole, amoxicillin, amoxicillin/clavulanic acid, clindamycin, doxy-cycline, ciprofloxacin and azithromycin. Most of the patients were female, age ranging between 40 to 50 years. Majority of the patients frequently had scaling and depths of periodontal pockets in infected teeth were 5-8 mm and most of them had hemorrhage during sampling. Susceptibility testing revealed a sensitivity of 100% of P. gingivalis to azithromycin, doxycycline and amoxicillin/clavulanic acid but lower susceptibilities were found for the rest of antibiotic agents evaluated. Frequent scaling in women aged between 40-50 years had positive correlation with chronic periodontitis. The application of antibiotics in conjuction with mechanical debridation, may reflect in the level of resistance of P. gingivalis in patients with chronic periodontal infections. This could suggest periodical antibiotic susceptibility testing is necessary to determine the efficacy of antimicrobial agents if the perfect curing of chronic periodontal diseases after mechanical debridation is meant. Further clinical studies are required to confirm the in vitro results. The only limitation in this study was identification of bacteria to species rather than subspecies level.

Experimental investigation of the susceptibility of Italian Culex pipiens mosquitoes to Zika virus infection.

Science.gov (United States)

Boccolini, Daniela; Toma, Luciano; Di Luca, Marco; Severini, Francesco; Romi, R; Remoli, Maria Elena; Sabbatucci, Michela; Venturi, Giulietta; Rezza, Giovanni; Fortuna, Claudia

2016-09-01

We investigated the susceptibility of an Italian population of Culex pipiens mosquitoes to Zika virus (ZIKV) infection, tested in parallel with Aedes aegypti, as a positive control. We analysed mosquitoes at 0, 3, 7, 10, 14, 20 and 24 days after an infectious blood meal. Viral RNA was detected in the body of Cx. pipiens up to three days post-infection, but not at later time points. Our results indicate that Cx. pipiens is not susceptible to ZIKV infection. This article is copyright of The Authors, 2016.

Quantitative Susceptibility Mapping Reveals an Association between Brain Iron Load and Depression Severity

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Shun Yao

2017-08-01

Full Text Available Previous studies have detected abnormal serum ferritin levels in patients with depression; however, the results have been inconsistent. This study used quantitative susceptibility mapping (QSM for the first time to examine brain iron concentration in depressed patients and evaluated whether it is related to severity. We included three groups of age- and gender-matched participants: 30 patients with mild-moderate depression (MD, 14 patients with major depression disorder (MDD and 20 control subjects. All participants underwent MR scans with a 3D gradient-echo sequence reconstructing for QSM and performed the 17-item Hamilton Depression Rating Scale (HDRS test. In MDD, the susceptibility value in the bilateral putamen was significantly increased compared with MD or control subjects. In addition, a significant difference was also observed in the left thalamus in MDD patients compared with controls. However, the susceptibility values did not differ between MD patients and controls. The susceptibility values positively correlated with the severity of depression as indicated by the HDRS scores. Our results provide evidence that brain iron deposition may be associated with depression and may even be a biomarker for investigating the pathophysiological mechanism of depression.

Antimicrobial susceptibility and tetracycline resistance determinant genotyping of Gallibacterium anatis

DEFF Research Database (Denmark)

Bojesen, Anders M.; Vazquez, Maria E.; Bager, Ragnhild J.

2011-01-01

no determinant was identified.This is the first study to determine the antimicrobial susceptibility of Gallibacterium anatis by MIC revealing that multidrug resistance is very common among G. anatis field isolates. tet(B) was by far the most common determinant identified but future work should aim at identifying......The present investigation was undertaken to assess the antimicrobial susceptibility of a collection of 58 Gallibacterium isolates. All strains were tested by the broth dilution method using the veterinary fastidious medium. A total of 46 field strains were tested, whereof 23 were clinical isolates....... Multidrug resistance (resistance towards≥three drugs) was observed for 65% of the field strains and only two strains were susceptible to all compounds. Most prominently, resistance to tetracycline and sulfamethoxazole was observed in 92% and 97% of the field strains, respectively. For comparison...

Antibiotic susceptibility profiles of oral pathogens

NARCIS (Netherlands)

Veloo, A. C. M.; Seme, K.; Raangs, Gerwin; Rurenga, P.; Singadji, Z.; Wekema - Mulder, G.; van Winkelhoff, A. J.

2012-01-01

Periodontitis is a bacterial disease that can be treated with systemic antibiotics. The aim of this study was to establish the antibiotic susceptibility profiles of five periodontal pathogens to six commonly used antibiotics in periodontics. A total of 247 periodontal bacterial isolates were tested

Susceptibility of Seven Termite Species (Isoptera) to the Entomopathogenic Fungus Metarhizium anisopliae

OpenAIRE

Chouvenc , Thomas; Su , Nan-Yao; Robert , Alain

2009-01-01

Seven termite species (Isoptera) from five families were tested for disease susceptibility against the entomopathogenic fungus Metarhizium anisopliae using a standard protocol: Mastotermes darwiniensis (Mastotermitidae), Hodotermopsis sjoestedti (Termopsidae), Hodotermes mossambicus (Hodotermitidae), Kalotermes flavicollis (Kalotermitidae), Reticulitermes flavipes and Prorhinotermes canalifrons (Rhinotermitidae), and Nasutitermes voeltzkowi (Termitidae). Our results showed a large diversity i...

A New Twist to the Kirby-Bauer Antibiotic Susceptibility Test Activity?Increasing Antibiotic Sensitivity of Pseudomonas fluorescens through Thermal Stress

OpenAIRE

Gerbig, Donald G.; Engohang-Ndong, Jean; Aubihl, Heather

2013-01-01

Antibiotic sensitivity and the effect of temperature on microbial growth are two standard laboratory activities found in most microbial laboratory manuals. We have found a novel way to combine the two activities to demonstrate how temperature can influence antibiotic sensitivity using a standard incubator in instructional laboratory settings. This activity reinforces the important concepts of microbial growth and temperature along with Kirby-Bauer antibiotic susceptibility testing. We found t...

Linezolid susceptibility in Helicobacter pylori, including strains with multidrug resistance.

Science.gov (United States)

Boyanova, Lyudmila; Evstatiev, Ivailo; Gergova, Galina; Yaneva, Penka; Mitov, Ivan

2015-12-01

Only a few studies have evaluated Helicobacter pylori susceptibility to linezolid. The aim of the present study was to assess linezolid susceptibility in H. pylori, including strains with double/multidrug resistance. The susceptibility of 53 H. pylori strains was evaluated by Etest and a breakpoint susceptibility testing method. Helicobacter pylori resistance rates were as follows: amoxicillin, 1.9%; metronidazole, 37.7%; clarithromycin, 17.0%; tetracycline, 1.9%; levofloxacin, 24.5%; and linezolid (>4 mg/L), 39.6%. The linezolid MIC50 value was 31.2-fold higher than that of clarithromycin and 10.5-fold higher than that of levofloxacin; however, 4 of 11 strains with double/multidrug resistance were linezolid-susceptible. The MIC range of the oxazolidinone agent was larger (0.125-64 mg/L) compared with those in the previous two reports. The linezolid resistance rate was 2.2-fold higher in metronidazole-resistant strains and in strains resistant to at least one antibiotic compared with the remaining strains. Briefly, linezolid was less active against H. pylori compared with clarithromycin and levofloxacin, and linezolid resistance was linked to resistance to metronidazole as well as to resistance to at least one antibiotic. However, linezolid activity against some strains with double/multidrug resistance may render the agent appropriate to treat some associated H. pylori infections following in vitro susceptibility testing of the strains. Clinical trials are required to confirm this suggestion. Copyright © 2015 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

The study of past damaging hydrogeological events for damage susceptibility zonation

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O. Petrucci

2008-08-01

susceptibility levels, on account of both the low population density and high average rainfall characterizing these mountainous areas.

The future analysis of further DHEs, using the tested procedure, can strengthen the obtained zonation. Afterwards, the results can prove useful in establishing civil defence plans, emergency management, and prioritizing hazard mitigation measures.

Susceptibility of Several Northeastern Conifers to Fusarium circinatum and Strategies for Biocontrol

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Jorge Martín-García

2017-08-01

Full Text Available Fusarium circinatum, the causal of pine pitch canker disease (PPC, is now considered among the most important pathogens of Pinaceae in the world. Although in Europe PPC is only established in the Iberian Peninsula, the potential endangered areas cover over 10 million hectares under the current host distribution and climatic conditions. It is therefore a priority to test the susceptibility of those species and their provenances, within Central and Northern Europe and find biological control agents (BCAs against the disease. In this study, the susceptibility of Pinus sylvestris, P. mugo and Picea abies Romanian provenances to F. circinatum was tested using three inoculum doses. In parallel, the potential use of Trichoderma atroviride and Trichoderma viride as BCAs against F. circinatum was also tested. This study has demonstrated, for the first time, the susceptibility of P. mugo to F. circinatum. Likewise, the susceptibility of P. abies was also confirmed. The fact that the Romanian provenance of P. sylvestris has not been susceptible to F. circinatum suggests genetic resistance as a potential tool to manage the disease. This, together with the apparent effectiveness of Trichoderma species as BCAs, seems to indicate that an integrated management of the disease might be feasible.

An analytical method for assessing stage-specific drug activity in Plasmodium vivax malaria: implications for ex vivo drug susceptibility testing.

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Douglas H Kerlin

Full Text Available The emergence of highly chloroquine (CQ resistant P. vivax in Southeast Asia has created an urgent need for an improved understanding of the mechanisms of drug resistance in these parasites, the development of robust tools for defining the spread of resistance, and the discovery of new antimalarial agents. The ex vivo Schizont Maturation Test (SMT, originally developed for the study of P. falciparum, has been modified for P. vivax. We retrospectively analysed the results from 760 parasite isolates assessed by the modified SMT to investigate the relationship between parasite growth dynamics and parasite susceptibility to antimalarial drugs. Previous observations of the stage-specific activity of CQ against P. vivax were confirmed, and shown to have profound consequences for interpretation of the assay. Using a nonlinear model we show increased duration of the assay and a higher proportion of ring stages in the initial blood sample were associated with decreased effective concentration (EC(50 values of CQ, and identify a threshold where these associations no longer hold. Thus, starting composition of parasites in the SMT and duration of the assay can have a profound effect on the calculated EC(50 for CQ. Our findings indicate that EC(50 values from assays with a duration less than 34 hours do not truly reflect the sensitivity of the parasite to CQ, nor an assay where the proportion of ring stage parasites at the start of the assay does not exceed 66%. Application of this threshold modelling approach suggests that similar issues may occur for susceptibility testing of amodiaquine and mefloquine. The statistical methodology which has been developed also provides a novel means of detecting stage-specific drug activity for new antimalarials.

Absolute method of measuring magnetic susceptibility

Science.gov (United States)

Thorpe, A.; Senftle, F.E.

1959-01-01

An absolute method of standardization and measurement of the magnetic susceptibility of small samples is presented which can be applied to most techniques based on the Faraday method. The fact that the susceptibility is a function of the area under the curve of sample displacement versus distance of the magnet from the sample, offers a simple method of measuring the susceptibility without recourse to a standard sample. Typical results on a few substances are compared with reported values, and an error of less than 2% can be achieved. ?? 1959 The American Institute of Physics.

Helicobacter pylori from Peptic Ulcer Patients in Uganda Is Highly Resistant to Clarithromycin and Fluoroquinolones: Results of the GenoType HelicoDR Test Directly Applied on Stool

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Denish Calmax Angol

2017-01-01

Full Text Available Background. Around 70–90% of peptic ulcer disease (PUD is due to Helicobacter pylori and requires treatment with antimicrobials to which these bacteria are susceptible. Common H. pylori diagnostic tests do not provide drug susceptibility data. Using the GenoType HelicoDR PCR test designed for gastric biopsies for simultaneous detection of H. pylori and its resistance to clarithromycin (CLA/fluoroquinolones (FLQ, we present evidence for stool as an optional test specimen and also provide data on prevalence of H. pylori resistance to CLA and FLQ in Uganda. Methods. Stool from 142 symptomatic PUD patients at three hospitals in Kampala was screened for H. pylori using a rapid antigen test. The GenoType HelicoDR test was run on all H. pylori antigen positives to determine PCR positivity and resistance to CLA/FLQ. Results. Thirty-one samples (22% were H. pylori antigen positive, and 21 (68% of these were H. pylori PCR positive. Six of the 21 (29% were resistant to CLA and eight to FLQ (42%, while two gave invalid FLQ resistance results. Conclusion. Stool is a possible specimen for the GenoType HelicoDR test for rapid detection of H. pylori and drug resistance. In Uganda, Helicobacter pylori is highly resistant to CLA and FLQ.

Effect of microstructure on the sulphide stress cracking susceptibility of a high strength pipeline steel

Energy Technology Data Exchange (ETDEWEB)

Ramirez, E. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas-UAEM, Av. Universidad 1001, 62209-Cuernavaca, Mor. (Mexico); Gonzalez-Rodriguez, J.G. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas-UAEM, Av. Universidad 1001, 62209-Cuernavaca, Mor. (Mexico)], E-mail: ggonzalez@uaem.mx; Torres-Islas, A.; Serna, S. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas-UAEM, Av. Universidad 1001, 62209-Cuernavaca, Mor. (Mexico); Campillo, B. [Intituto de Ciencias Fisicas-Facultad de Quimicas-Universidad Nacional Autonoma de Mexico Cuernavaca, Mor. (Mexico); Dominguez-Patino, G. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas-UAEM, Av. Universidad 1001, 62209-Cuernavaca, Mor. (Mexico); Juarez-Islas, J.A. [Instituto de Investigaciones en Materiales-Universidad Nacional Autonoma de Mexico, Circuito Exterior S/N, Cd. Universitaria, C.P. 04510, Mexico, D.F. (Mexico)

2008-12-15

The sulphide stress cracking (SSC) susceptibility of a newly developed high strength microalloyed steel with three different microstructures has been evaluated using the slow strain rate testing (SSRT) technique. Studies were complemented with potentiodynamic polarization curves and hydrogen permeation measurements. Material included a C-Mn steel having Ni, Cu, and Mo as main microalloying elements with three microstructures: martensitic, ferritic and ferritic + bainitic. Testing temperatures included 25, 50, 70 and 90 deg. C. Detailed SEM observations of the microstructure and fracture surfaces were done to identify possible degradation mechanisms. The results showed that in all cases, the corrosion rate, number of hydrogen atoms at the surface and the percentage reduction in area increased with temperature. The steel with a martensitic microstructure had the highest SSC susceptibility at all temperatures, whereas the ferritic steels were susceptible only at 25 deg. C, and the most likely mechanism is hydrogen embrittlement assisted by anodic dissolution.

Antimicrobial susceptibility of porcine Brachyspira hyodysenteriae and Brachyspira pilosicoli isolated in Sweden between 1990 and 2010.

Science.gov (United States)

Pringle, Märit; Landén, Annica; Unnerstad, Helle Ericsson; Molander, Benedicta; Bengtsson, Björn

2012-09-21

The anaerobic spirochetes Brachyspira hyodysenteriae and Brachyspira pilosicoli cause diarrheal diseases in pigs. Their fastidious nature has hampered standardization of methods for antimicrobial susceptibility testing. For monitoring of antimicrobial susceptibility wild type cutoff values are needed to define where the wild type distribution of MICs ends and no approved cutoffs are available for Brachyspira spp. In this study antimicrobial susceptibility data for both species (in total 906 isolates) were compiled and analyzed and wild type cut off values for B. hyodysenteriae proposed. The MICs of tiamulin, valnemulin, tylosin, tylvalosin, doxycycline and lincomycin were determined by broth dilution in brain heart infusion broth supplemented with 10% fetal calf serum. The compiled MICs from the broth dilution tests of the B. hyodysenteriae type strain, B78T (ATCC® 27164T), showed that the method yields reproducible results. In an international perspective the frequencies of isolates with decreased antimicrobial susceptibility were low among both B. hyodysenteriae and B. pilosicoli. However, in B. pilosicoli a constant level of 10-15% isolates with tiamulin MICs >4 μg/ml was detected between 2002 and 2010 and in B. hyodysenteriae a gradual increase in tiamulin MICs was seen between 1990 and 2003 although this increase has ceased during the last years. The wild type cutoff values proposed for B. hyodysenteriae are: tiamulin >0.25 μg/ml, valnemulin >0.125 μg/ml, tylosin >16 μg/ml, tylvalosin >1 μg/ml, lincomycin >1 μg/ml and doxycycline >0.5 μg/ml. The broth dilution method used in this study has over the years generated tightly grouped MIC populations for the field isolates and reproducible results for the control strain B78T and is therefore a suitable antimicrobial susceptibility test method for monitoring of Brachyspira spp. Here we propose wild type cutoff values for six antimicrobial agents for B. hyodysenteriae tested by broth dilution based on MIC

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

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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.

The Slab Method to Measure the Topological Susceptibility

CERN Document Server

Bietenholz, Wolfgang; de Forcrand, Philippe; Dromard, Arthur; Gerber, Urs

2016-10-11

In simulations of a model with topological sectors, algorithms which proceed in small update steps tend to get stuck in one sector, especially on fine lattices. This distorts the numerical results, in particular it is not straightforward to measure the topological susceptibility chi_t. We test a method to measure chi_t even if configurations from only one sector are available. It is based on the topological charges in sub-volumes, which we denote as "slabs". This enables the evaluation of chi_t, as we demonstrate with numerical results for non-linear sigma-models and for 2-flavour QCD.

Global stability of a susceptible-infected-susceptible epidemic model on networks with individual awareness

International Nuclear Information System (INIS)

Li Ke-Zan; Xu Zhong-Pu; Zhu Guang-Hu; Ding Yong

2014-01-01

Recent research results indicate that individual awareness can play an important influence on epidemic spreading in networks. By local stability analysis, a significant conclusion is that the embedded awareness in an epidemic network can increase its epidemic threshold. In this paper, by using limit theory and dynamical system theory, we further give global stability analysis of a susceptible-infected-susceptible (SIS) epidemic model on networks with awareness. Results show that the obtained epidemic threshold is also a global stability condition for its endemic equilibrium, which implies the embedded awareness can enhance the epidemic threshold globally. Some numerical examples are presented to verify the theoretical results. (interdisciplinary physics and related areas of science and technology)

Color preferences in participants with high or low hypnotic susceptibility

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Yu E

2018-01-01

Full Text Available Enyan Yu,1,2 Junpeng Zhu,1,2 Yunfei Tan,1,2 Zhengluan Liao,1,2 Yaju Qiu,1,2 Bingren Zhang,3 Chu Wang,3 Wei Wang3 1Department of Psychiatry, Zhejiang Provincial People’s Hospital, Hangzhou, People’s Republic of China; 2Department of Psychiatry, People’s Hospital of Hangzhou Medical College, Hangzhou, People’s Republic of China; 3Department of Clinical Psychology and Psychiatry/School of Public health, Zhejiang University College of Medicine, Hangzhou, People’s Republic of China Purpose: Color preferences vary among normal individuals and psychiatric patients, and this might be related to their different levels of hypnotic susceptibility. We hypothesized that individuals with higher hypnotic susceptibility prefer more arousing colors such as red.Patients and methods: Out of 440 participants, we selected 70 with higher (HIGH and 66 with lower (LOW hypnotic susceptibilities, and asked them to undergo the Stanford Hypnotic Susceptibility Scale: Form C (SHSSC test, then to order their preferences of 11 colors.Results: The HIGH group preferred red more and scored higher on the total SHSSC. The preference order of black was negatively predicted by the SHSSC Taste hallucination but positively by Arm rigidity, and the preference of yellow was positively predicted by Posthypnotic amnesia and Taste hallucination in the HIGH group.Conclusion: The red preference and the SHSSC associations with black and yellow preferences in participants with high hypnotic susceptibility help to clarify the individual difference of color preference and provide research hints for behavioral studies in normal individuals and psychiatric patients. Keywords: color perception, healthy people, the Stanford Hypnotic Susceptibility Scale: Form C (SHSSC

Simple, direct drug susceptibility testing technique for diagnosis of drug-resistant tuberculosis in resource-poor settings.

Science.gov (United States)

Kim, C-K; Joo, Y-T; Lee, E P; Park, Y K; Kim, H-J; Kim, S J

2013-09-01

The Korean Institute of Tuberculosis, Seoul, Republic of Korea. To develop a simple, direct drug susceptibility testing (DST) technique using Kudoh-modified Ogawa (KMO) medium. The critical concentrations of isoniazid (INH), rifampicin (RMP), kanamycin (KM) and ofloxacin (OFX) for KMO medium were calibrated by comparing the minimal inhibitory concentrations (MICs) against clinical isolates of Mycobacterium tuberculosis on KMO with those on Löwenstein-Jensen (LJ). The performance of the direct KMO DST technique was evaluated on 186 smear-positive sputum specimens and compared with indirect LJ DST. Agreement of MICs on direct vs. indirect DST was high for INH, RMP and OFX. KM MICs on KMO were ∼10 g/ml higher than those on LJ. The critical concentrations of INH, RMP, OFX and KM for KMO were therefore set at 0.2, 40.0, 2.0, and 40.0 g/ml. The evaluation of direct DST of smear-positive sputum specimens showed 100% agreement with indirect LJ DST for INH and RMP. However, the respective susceptible and resistant predictive values were 98.8% and 100% for OFX, and 100% and 80% for KM. Direct DST using KMO is useful, with clear advantages of a shorter turnaround time, procedural simplicity and low cost compared to indirect DST. It may be most indicated in resource-poor settings for programmatic management of drug-resistant tuberculosis.

Changes in the antibiotic susceptibility of anaerobic bacteria from 2007-2009 to 2010-2012 based on the CLSI methodology.

Science.gov (United States)

Hastey, Christine J; Boyd, Halsey; Schuetz, Audrey N; Anderson, Karen; Citron, Diane M; Dzink-Fox, Jody; Hackel, Meredith; Hecht, David W; Jacobus, Nilda V; Jenkins, Stephen G; Karlsson, Maria; Knapp, Cynthia C; Koeth, Laura M; Wexler, Hannah; Roe-Carpenter, Darcie E

2016-12-01

Antimicrobial susceptibility testing of anaerobic isolates was conducted at four independent sites from 2010 to 2012 and compared to results from three sites during the period of 2007-2009. This data comparison shows significant changes in antimicrobial resistance in some anaerobic groups. Therefore, we continue to recommend institutions regularly perform susceptibility testing when anaerobes are cultured from pertinent sites. Annual generation of an institutional-specific antibiogram is recommended for tracking of resistance trends over time. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of Inventory Bias on Landslide Susceptibility Calculations

Science.gov (United States)

Stanley, T. A.; Kirschbaum, D. B.

2017-01-01

Many landslide inventories are known to be biased, especially inventories for large regions such as Oregon's SLIDO or NASA's Global Landslide Catalog. These biases must affect the results of empirically derived susceptibility models to some degree. We evaluated the strength of the susceptibility model distortion from postulated biases by truncating an unbiased inventory. We generated a synthetic inventory from an existing landslide susceptibility map of Oregon, then removed landslides from this inventory to simulate the effects of reporting biases likely to affect inventories in this region, namely population and infrastructure effects. Logistic regression models were fitted to the modified inventories. Then the process of biasing a susceptibility model was repeated with SLIDO data. We evaluated each susceptibility model with qualitative and quantitative methods. Results suggest that the effects of landslide inventory bias on empirical models should not be ignored, even if those models are, in some cases, useful. We suggest fitting models in well-documented areas and extrapolating across the study region as a possible approach to modeling landslide susceptibility with heavily biased inventories.

Investigation of the susceptibility to solidification cracking in copper alloys

Energy Technology Data Exchange (ETDEWEB)

Warren, Richard [Avesta Sheffield R and D, Avesta (Sweden)

2000-04-01

A test procedure has been developed at LuTH for investigating the susceptibility to cracking at high temperatures in weldments. It has been proposed to adapt this testing procedure to investigate the cracking susceptibility at high temperatures during strip casting of certain copper alloys. Six different materials were selected for investigation - OFHC copper, tellurium containing copper, 4% tin bronze, 6% tin bronze, 30% zinc brass and 35% zinc brass. The aim of the investigation was to characterize the cracking susceptibility of the candidate materials so as to be able to rank and compare them in a quantitative manner. A further aim of the work was to study the suitability of using the data on the cracking indices generated in the present work in thermomechanical models of the casting process to optimize the casting parameters for each of the materials.

Evaluation by the Double Loop Electrochemical Potentiokinetic Reactivation Test of Aged Ferritic Stainless Steel Intergranular Corrosion Susceptibility

Science.gov (United States)

Sidhom, H.; Amadou, T.; Braham, C.

2010-12-01

An experimental design method was used to determine the effect of factors that significantly affect the response of the double loop-electrochemical potentiokinetic reactivation (DL-EPR) test in controlling the susceptibility to intergranular corrosion (IGC) of UNS S43000 (AISI 430) ferritic stainless steel. The test response is expressed in terms of the reactivation/activation current ratio ( I r / I a pct). Test results analysed by the analysis of variance (ANOVA) method show that the molarity of the H2SO4 electrolyte and the potential scanning rate have a more significant effect on the DL-EPR test response than the temperature and the depassivator agent concentration. On the basis of these results, a study was conducted in order to determine the optimal operating conditions of the test as a nondestructive technique for evaluating IGC resistance of ferritic stainless steel components. Three different heat treatments are considered in this study: solution annealing (nonsensitized), aging during 3 hours at 773 K (500 °C) (slightly sensitized), and aging during 2 hours at 873 K (600 °C) (highly sensitized). The aim is to find the operating conditions that simultaneously ensure the selectivity of the attack (intergranular and chromium depleted zone) and are able to detect the effect of low dechromization. It is found that a potential scanning rate of 2.5 mV/s in an electrolyte composed of H2SO4 3 M solution without depassivator, at a temperature around 293 K (20 °C), is the optimal operating condition for the DL-EPR test. Using this condition, it is possible to assess the degree of sensitization (DOS) to the IGC of products manufactured in ferritic stainless steels rapidly, reliably, and quantitatively. A time-temperature-start of sensitization (TTS) diagram for the UNS S43000 (France Inox, Villepinte, France) stainless steel was obtained with acceptable accuracy by this method when the IGC sensitization criterion was set to I r / I a > 1 pct. This diagram is in

[Susceptibility of natural populations of dengue vector to insecticides in Colombia].

Science.gov (United States)

Santacoloma, Liliana; Chaves, Bernardo; Brochero, Helena Luisa

2012-09-01

Physiological resistance of natural population of Aedes aegypti to insecticides contribute to the decreased efficacy of chemical control as a main control strategy during dengue outbreaks. The susceptibility status of Ae. aegypti was assessed for the carbamate propoxur, the adulticide malathion and the larvicide temephos on 13 natural populations of Ae. aegypti immature forms were taken from 8 Colombian localities. These included the following: Bucaramanga (1), Sabana de Torres (2), Girardot (2), La Mesa (2), Villavicencio (2), Puerto López (2), San José del Guaviare (1) and Florencia (1). Susceptibility tests mainly consisted of the standardized bioassay outlined by WHO (1981) and CDC bottles (1998). Colorimetric tests were undertaken to determine enzyme levels possibly responsible for the reduction of susceptibility to organophosphate and carbamate insecticides. All specimens demonstrated susceptibility to malathion and propoxur insecticides. Four of the 13 populations revealed susceptibility to the temephos larvicide. Seven of 11 populations showed a limited increase in values for nonspecific esterase enzymes. The Bucaramanga population was the only one which showed an increase in the cytochrome P450 monooxygenases enzymes. Neither population was found with modified acetilcolinesterase. The widespread susceptibility to organophosphates used as adulticides indicated that malathion, the most used insecticide in Colombia, remains effective in interrupting the transmission of dengue. Physiological resistance to insecticides occurring in communities of a single township proved to be a localized phenomenon.

Measurement of susceptibility artifacts with histogram-based reference value on magnetic resonance images according to standard ASTM F2119.

Science.gov (United States)

Heinrich, Andreas; Teichgräber, Ulf K; Güttler, Felix V

2015-12-01

The standard ASTM F2119 describes a test method for measuring the size of a susceptibility artifact based on the example of a passive implant. A pixel in an image is considered to be a part of an image artifact if the intensity is changed by at least 30% in the presence of a test object, compared to a reference image in which the test object is absent (reference value). The aim of this paper is to simplify and accelerate the test method using a histogram-based reference value. Four test objects were scanned parallel and perpendicular to the main magnetic field, and the largest susceptibility artifacts were measured using two methods of reference value determination (reference image-based and histogram-based reference value). The results between both methods were compared using the Mann-Whitney U-test. The difference between both reference values was 42.35 ± 23.66. The difference of artifact size was 0.64 ± 0.69 mm. The artifact sizes of both methods did not show significant differences; the p-value of the Mann-Whitney U-test was between 0.710 and 0.521. A standard-conform method for a rapid, objective, and reproducible evaluation of susceptibility artifacts could be implemented. The result of the histogram-based method does not significantly differ from the ASTM-conform method.

Status of NRC approval of EPRI electromagnetic interference susceptibility testing guidelines for digital equipment

International Nuclear Information System (INIS)

James, R.W.; Shank, J.W.; Yoder, C.

1996-01-01

Historically, nuclear power plants installing digital equipment have been required to conduct expensive, site-specific electromagnetic interference (EMI) surveys to demonstrate that EMI will not affect the operation of sensitive electronic equipment. Consequently, EPRI formed a Utility Working Group which developed a set of generic EMI susceptibility testing guidelines, which were published as an EPRI report in September 1994. These guidelines are based upon EMI survey data obtained from several different plants and include criteria for determining their applicability. The Working Group interacted with NRC staff to obtain NRC approval. In April 1996, the NRC issued a Safety Evaluation Report (SER) endorsing the guidelines as a valid means of demonstrating EMI compatibility. The issuance of this SER was conditional on issuing a revision to the EPRI EMI Guidelines. This paper summarizes the guidelines, the NRC SER, and the current status of Revision 1 to the report

Susceptibility assessment of landslides: A comparison of two GIS-based methods in the region of Al Hoceima (Eastern Rif, Morocco.

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El Fahchouch A. N.

2018-01-01

Full Text Available The evaluation of the degree of susceptibility to landslides has become a major concern in mountainous areas, it is a key component of manager policies efforts in disaster prevention, mitigate risk and manage the consequences. The region of Al Hoceima is one of most mountain regions in Morocco, and is highly exposed landslides events. For this reason, the area was selected in order to determine its susceptibility to landslides using two methods. The purpose of this study is to evaluate and to compare the results of multivariate (logical regression and bivariate (landslide susceptibility methods in Geographical Information System (GIS based landslide susceptibility assessment procedures. In order to achieve this goal, the selected methods were compared by the Seed Cell Area Indexes (SCAI and by the spatial locations of the resultant susceptibility pixels. We found that both of the methods converge in 80% of the area; however, the weighting algorithm in the bivariate technique (landslide susceptibility method had some severe deficiencies, as the resultant hazard classes in overweighed areas did not converge with the factual landslide inventory map. The result of the multivariate technique (logical regression was more sensitive to the different local features of the test zone and it resulted in more accurate and homogeneous susceptibility maps. This information may have direct applications in landslides susceptibility research programs and can assist decision-makers in the implementation of preventive management strategies in the most sensitive areas.

Correlates of susceptibility to smoking among Mexican origin youth residing in Houston, Texas: A cross-sectional analysis

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Prokhorov Alexander V

2008-09-01

Full Text Available Abstract Background Survey data suggest that in Texas Latino youth exhibit higher rates of susceptibility to smoking than youth from other ethnic groups. In this analysis we examined the relationship between susceptibility to smoking and well-known risk factors associated with smoking initiation among a cohort of 11 to 13 year old Mexican origin youth residing in Houston, Texas. Methods We analyzed cross-sectional survey data from 1,187 participants who reported they had never smoked, even a puff of a cigarette. The survey assessed peer and family social influence, school and neighborhood characteristics, level of family acculturation and socioeconomic status, and attitudes toward smoking. Bivariate associations, Student's t-tests, and logistic regression analysis were used to examine predictors of susceptibility. Results Overall, 22.1% of the never-smokers were susceptible to smoking. Boys were more likely to be susceptible than girls (25.6% vs. 18.9%, and susceptible children were slightly older than non-susceptible children (12.1 vs. 11.8 years. In addition, multivariate analyses revealed that positive expectations about smoking exerted the strongest influence on susceptibility status (odds ratio = 4.85. Multivariate analyses further revealed that compared to non-susceptible participants, susceptibles were more likely to report peer influences supportive of smoking, lower subjective social status and more detentions at school, more temptations to try smoking and to have a mother and a brother who smokes. Conclusion Our findings suggest that interventions that target positive expectations about smoking may be useful in this population. Furthermore, because youth encounter smoking-initiation risk factors in different social environments, our results underscore the continued need for both family- and school-based primary prevention programs to adequately combat their influence. The results also can be used to inform the development of culturally

A Low Cost/Low Power Open Source Sensor System for Automated Tuberculosis Drug Susceptibility Testing

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Kyukwang Kim

2016-06-01

Full Text Available In this research an open source, low power sensor node was developed to check the growth of mycobacteria in a culture bottle with a nitrate reductase assay method for a drug susceptibility test. The sensor system reports the temperature and color sensor output frequency change of the culture bottle when the device is triggered. After the culture process is finished, a nitrite ion detecting solution based on a commercial nitrite ion detection kit is injected into the culture bottle by a syringe pump to check bacterial growth by the formation of a pigment by the reaction between the solution and the color sensor. Sensor status and NRA results are broadcasted via a Bluetooth low energy beacon. An Android application was developed to collect the broadcasted data, classify the status of cultured samples from multiple devices, and visualize the data for the end users, circumventing the need to examine each culture bottle manually during a long culture period. The authors expect that usage of the developed sensor will decrease the cost and required labor for handling large amounts of patient samples in local health centers in developing countries. All 3D-printerable hardware parts, a circuit diagram, and software are available online.

A landslide susceptibility map of Africa

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Broeckx, Jente; Vanmaercke, Matthias; Duchateau, Rica; Poesen, Jean

2017-04-01

Studies on landslide risks and fatalities indicate that landslides are a global threat to humans, infrastructure and the environment, certainly in Africa. Nonetheless our understanding of the spatial patterns of landslides and rockfalls on this continent is very limited. Also in global landslide susceptibility maps, Africa is mostly underrepresented in the inventories used to construct these maps. As a result, predicted landslide susceptibilities remain subject to very large uncertainties. This research aims to produce a first continent-wide landslide susceptibility map for Africa, calibrated with a well-distributed landslide dataset. As a first step, we compiled all available landslide inventories for Africa. This data was supplemented by additional landslide mapping with Google Earth in underrepresented regions. This way, we compiled 60 landslide inventories from the literature (ca. 11000 landslides) and an additional 6500 landslides through mapping in Google Earth (including 1500 rockfalls). Various environmental variables such as slope, lithology, soil characteristics, land use, precipitation and seismic activity, were investigated for their significance in explaining the observed spatial patterns of landslides. To account for potential mapping biases in our dataset, we used Monte Carlo simulations that selected different subsets of mapped landslides, tested the significance of the considered environmental variables and evaluated the performance of the fitted multiple logistic regression model against another subset of mapped landslides. Based on these analyses, we constructed two landslide susceptibility maps for Africa: one for all landslide types and one excluding rockfalls. In both maps, topography, lithology and seismic activity were the most significant variables. The latter factor may be surprising, given the overall limited degree of seismicity in Africa. However, its significance indicates that frequent seismic events may serve as in important

Clinical and Diagnostic Aspects of Brucellosis and Antimicrobial Susceptibility of Brucella Isolates in Hamedan, Iran.

Science.gov (United States)

Torkaman Asadi, Fatemeh; Hashemi, Seyyed Hamid; Alikhani, Mohammad Yousef; Moghimbeigi, Abbas; Naseri, Zahra

2017-05-24

Current drug regimens for brucellosis are associated with relatively high rates of therapeutic failure or relapse. Reduced antimicrobial susceptibility of Brucella spp. has been proposed recently as a potential cause of therapeutic failure. The aim of this study was to evaluate the antibiotic resistance pattern of Brucella melitensis clinical isolates by E-test method in Hamadan, west of Iran. In a 15-month period, all patients with suspected brucellosis were enrolled. Blood specimens were collected for diagnosis of brucellosis by BACTEC system and serological tests. Antimicrobial susceptibility of clinical isolates to 7 antibiotics was assessed by the E-test method. One hundred forty-nine patients with brucellosis were evaluated. 38.3% of cultures of clinical samples were positive for BACTEC system, of which 91.2% were associated with a positive serological test result. No significant associations were found between serology and the culture method. All Brucella isolates were susceptible to doxycycline, streptomycin, gentamicin, ciprofloxacin, and moxifloxacin. However, decreased sensitivity to rifampin and trimethoprim-sulfamethoxazole was found in 35.1% and 3.5% of isolates, respectively. Because of the high rates of intermediate sensitivity to rifampin among Brucella isolates, this drug should be prescribed with caution. We recommend restricting the use of rifampin for treatment of brucellosis except as an alternative drug for special situations.

Stress corrosion cracking susceptibility of the earthquake resistant NOM B457 Mexican steel

International Nuclear Information System (INIS)

Arganis J, C.R.

1994-01-01

The Mexican construction code was modified after the Mexico city 1985 earthquake, substituted the medium carbon reinforced steel NOM B6 by the new micro alloyed steel NOM B457 in 42 Kg/mm 2 grade. The present study reports the evaluation of the NOM B457 steel behavior in mortar with and without 2% wt. in chlorides and in Ca(OH) 2 saturated solutions. The results are compared with the NOM B6 steel behavior in the same conditions. The Stress Corrosion Cracking (SCC) is not present in all the conditions used in this study and there are not susceptibility potential range to SCC when the material is evaluated by electrochemical Tests, Constant Extension Rate Tests (CERT) and Constant Load Test at 80 % of yield stress. A susceptibility potential range to Hydrogen Induced Cracking (HIC) is detected, below -900 mV. vs Standard Calomel Electrode (SCE) by CERT at constant potential

Magnetic susceptibility of YbN

International Nuclear Information System (INIS)

Zhou, Y.; Bowen, S.P.; Koelling, D.D.; Monnier, R.

1991-01-01

Applying the Zwicknagl, Zevin, and Fulde (ZZF) approximation for the spectral densities of the occupied and empty f states resulting from a degenerate-Anderson-impurity model, which incorporates crystal fields, we compute the low-temperature magnetic susceptibility of YbN. The model, in which each crystal-field level couples to the band states with its own hybridization function, has previously been successfully applied without the ZZF approximation to explain the specific-heat structure at low temperatures. The ZZF approximation removes the spurious zero-temperature behavior of the parent noncrossing approximation for the susceptibility. Surprisingly, even at the low crystal-field degeneracy (N=2) of YbN, the Shiba relation is very nearly satisfied. The appropriate experimental impurity susceptibility for comparison is extracted from the measurement by removing an empirical exchange interaction. The resultant Kondo temperature (T 0 =8.49 K) is consistent with previous specific-heat estimates (10--11 K), and the agreement with experiment is good

Investigation of irradiation induced inter-granular stress corrosion cracking susceptibility on austenitic stainless steels for PWR by simulated radiation induced segregation materials

Energy Technology Data Exchange (ETDEWEB)

Yonezawa, Toshio; Fujimoto, Koji; Kanasaki, Hiroshi; Iwamura, Toshihiko [Mitsubishi Heavy Industries Ltd., Takasago R and D Center, Takasago, Hyogo (Japan); Nakada, Shizuo; Ajiki, Kazuhide [Mitsubishi Heavy Industries Ltd., Kobe Shipyard and Machinery Works, Kobe, Hyogo (Japan); Urata, Sigeru [General Office of Nuclear and Fossil Power Production, Kansai Electric Power Co., Inc., Osaka (Japan)

2000-07-01

An Irradiation Assisted Stress Corrosion Cracking (IASCC) has not been found in Pressurized Water Reactors (PWRs). However, the authors have investigated on the possibility of IASCC so as to be able to estimate the degradation of PWR plants up to the end of their lifetime. In this study, the authors melted the test alloys whose bulk compositions simulated the grain boundary compositions of irradiated Type 304 and Type 316 CW stainless steels. Low chromium, high nickel and silicon (12%Cr-28%Ni-3%Si) steel showed high susceptibility to PWSCC (Primary Water Stress Corrosion Cracking) by SSRT (Slow Strain Rate Tensile) test in simulated PWR primary water. PWSCC susceptibility of the test steels increases with a decrease of chromium content and a increase of nickel and silicon contents. The aged test steel included coherent M{sub 23}C{sub 6} carbides with matrices at the grain boundaries showed low PWSCC susceptibility. This tendency is in very good agreement with that of the PWSCC susceptibility of nickel based alloys X-750 and 690. From these results, if there is the possibility of IASCC for austenitic stainless steels in PWRs, in the future, the IASCC shall be caused by the PWSCC as a result of irradiation induced grain boundary segregation. (author)