Maboni, Grazieli; Gressler, Leticia T.; Espindola, Julia P.; Schwab, Marcelo; Tasca, Caiane; Potter, Luciana; de Vargas, Agueda Castagna
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
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.
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.
Meumann, Ella M; Mitchell, Brett G; McGregor, Alistair; McBryde, Emma; Cooley, Louise
This study assessed urinary Escherichia coli antibiotic susceptibility patterns in Tasmania, Australia, and examined their association with community antibiotic use. The susceptibility profiles of all urinary E. coli isolates collected in Tasmania between January 2010 and December 2012 were included. The amount of Pharmaceutical Benefits Scheme (PBS)-subsidised use of amoxicillin, amoxicillin/clavulanic acid (AMC), cefalexin, norfloxacin, ciprofloxacin and trimethoprim was retrieved (at the Tasmanian population level) and the number of defined daily doses per 1000 population per day in Tasmania for these antibiotics was calculated for each month during the study period. Antimicrobial susceptibility data were assessed for changes over time in the 3-year study period. Antimicrobial use and susceptibility data were assessed for seasonal differences and lag in resistance following antibiotic use. Excluding duplicates, 28145 E. coli isolates were included. Resistance levels were low; 35% of isolates were non-susceptible to amoxicillin, 14% were non-susceptible to trimethoprim and Tasmania's isolated geographical location. Significant seasonal variation in amoxicillin and AMC use is likely to be due to increased use of these antibiotics for treatment of respiratory tract infections in winter. Quinolone use is restricted by the PBS in Australia, which is the likely explanation for the low levels of quinolone use and resistance identified.
Savage, Rachel D.; Fowler, Robert A.; Rishu, Asgar H.; Bagshaw, Sean M.; Cook, Deborah; Dodek, Peter; Hall, Richard; Kumar, Anand; Lamontagne, François; Lauzier, François; Marshall, John; Martin, Claudio M.; McIntyre, Lauralyn; Muscedere, John; Reynolds, Steven; Stelfox, Henry T.; Daneman, Nick
Background: Surveillance of antimicrobial resistance is vital to guiding empirical treatment of infections. Collating and reporting routine data on clinical isolate testing may offer more timely information about resistance patterns than traditional surveillance network methods. Methods: Using routine microbiology testing data collected from the Bacteremia Antibiotic Length Actually Needed for Clinical Effectiveness retrospective cohort study, we conducted a descriptive secondary analysis among critically ill patients in whom bloodstream infections had been diagnosed in 14 intensive care units (ICUs) in Canada. The participating sites were located within tertiary care teaching hospitals and represented 6 provinces and 10 cities. More than 80% of the study population was accrued from 2011-2013. We assessed the epidemiologic features of the infections and corresponding antimicrobial susceptibility profiles. Susceptibility testing was done according to Clinical Laboratory Standards Institute guidelines at accredited laboratories. Results: A total of 1416 pathogens were isolated from 1202 patients. The most common organisms were Escherichia coli (217 isolates [15.3%]), Staphylococcus aureus (175 [12.4%]), coagulase-negative staphylococci (117 [8.3%]), Klebsiella pneumoniae (86 [6.1%]) and Streptococcus pneumoniae (85 [6.0%]). The contribution of individual pathogens varied by site. For 13 ICUs, gram-negative susceptibility rates were high for carbapenems (95.4%), tobramycin (91.2%) and piperacillin-tazobactam (90.0%); however, the proportion of specimens susceptible to these agents ranged from 75.0%-100%, 66.7%-100% and 75.0%-100%, respectively, across sites. Fewer gram-negative bacteria were susceptible to fluoroquinolones (84.5% [range 64.1%-97.2%]). A total of 145 patients (12.1%) had infections caused by highly resistant microorganisms, with significant intersite variation (range 2.6%-24.0%, χ2 = 57.50, p < 0.001). Interpretation: We assessed the epidemiologic
Full Text Available Background/Aim. In some clinical forms of human Campylobacter infections, such as prolonged diarrhea or associated with postinfections sequels, antibacterial treatment is necessary. The aim of the present study was to evaluate the antimicrobial susceptibility of thermophilic Campylobacter strains isolated from patients with diarrhea, as well as from patients with diarrhea followed by postinfections sequels, to drugs used in the therapy of enterocolitis, and to nalidixic acid used in laboratory identification and differentiation of thermophilic Campylobacter spp. Methods. We studied the antimicrobial susceptibility profiles of 131 Campylobacter strains isolated from patients with diarrhea (122 strains, diarrhea associated with rheumatic disorders (8 strains, and one strain isolated from a patient with Guillain-Barré Syndrome following Campylobacter enterocolitis. Susceptibility testing to erythromycin, gentamicin, tetracycline, chloramphenicol, ciprofloxacin and nalidixic acid was performed by the agar dilution method. Results. In the strains we investigated, resistance to gentamicin and chloramphenicol was not recorded, whereas a low rate of strains resistant to erythromycin (2.4%, a higher prevalence of strains resistant to tetracycline (9.9%, and a high level of resistance to ciprofloxacin (29.8% and nalidixic acid (33.3% were registered. All strains resistant to nalidixic acid were also resistant to ciprofloxacin. In addition, there was no difference in the occurrence of resistance between strains isolated from patients with diarrhea as compared to those isolated from patients with diarrhea followed by postinfection disorders. Conclusion. The fact that the most of Campylobacter strains were sensitive to erythromycin and all to gentamicin, makes erythromycin an antibiotic of choice in the treatment of Campylobacter diarrhea and gentamicin when parenteral therapy should be administered. Resistance to tetracycline and, especially, ciprofloxacin
Zhao, Pan; Zhang, Xiujuan; Du, Pengcheng; Li, Guilian; Li, Luxi; Li, Zhenjun
Nocardia species are ubiquitous in natural environments and can cause nocardiosis. Trimethoprim-sulfamethoxazole has long been the monotherapy treatment of choice, but resistance to this treatment has recently emerged. In this study, we used microplate Alamar Blue assays to determine the antimicrobial susceptibility patterns of 65 standard Nocardia isolates, including 28 type strains and 20 clinical Nocardia isolates, to 32 antimicrobial agents, including 13 little studied drugs. Susceptibility to the most commonly used drug, trimethoprim-sulfamethoxazole, was observed in 98% of the isolates. Linezolid, meropenem, and amikacin were also highly effective, with 98%, 95%, and 90% susceptibility, respectively, among the isolates. The isolates showed a high percentage of resistance or nonsusceptibility to isoniazid, rifampicin, and ethambutol. For the remaining antimicrobials, resistance was species-specific among isolates and was observed in traditional drug pattern types. In addition, the antimicrobial susceptibility profiles of a variety of rarely encountered standard Nocardia species are reported, as are the results for rarely reported clinical antibiotics. We also provide a timely update of antimicrobial susceptibility patterns that includes three new drug pattern types. The data from this study provide information on antimicrobial activity against specific Nocardia species and yield important clues for the optimization of species-specific Nocardia therapies. PMID:28252662
Lupetti, A; Barnini, S; Castagna, B; Capria, A-L; Nibbering, P H
Rapid identification and antimicrobial susceptibility profiling of the bacteria in blood cultures can result in clinical and financial benefits. Addition of saponin to the fluid from blood culture bottles promotes the recovery of the bacteria and thus may shorten the turnaround time of the microbiological analyses. In this study we compared the identification and susceptibility profiles of saponin-treated and untreated (standard method) blood cultures monomicrobial for Gram-positive cocci using Vitek 2. We concordantly identified 49 (89%) of 55 monobacterial cultures using the results with the standard method as reference. Complete categorical agreement between the susceptibility profiles with the new and the standard method was found for 26 (53%) of 49 isolates, while discrepancies were seen for 23 (47%) cultures. E-tests indicated that the new method resulted in a correct susceptibility profile for 8 (35%) of these 23 blood cultures. Therefore, 34 (69%) of 49 cultures showed a concordant/correct susceptibility profile for all antimicrobials with an overall error rate of 2.3%. Thus, addition of saponin to the fluid from blood culture bottles of the Bactec 9240 leads to the rapid (results available >or=12 hours earlier) and reliable identification and susceptibility profiling of Gram-positive cocci in blood cultures with Vitek 2.
Full Text Available Background: Urinary tract infections (UTIs are amongst the most common infections encountered globally and are usually treated empirically based on bacterial resistance to antibiotics for a given region. Unfortunately in Lesotho, no published studies are available to guide doctors in the treatment of UTIs. Treatment protocols for Western countries have been adopted, which may not be applicable for this region.Aim: To determine the antimicrobial susceptibility profile of uropathogens in outpatients at the Maluti Adventist Hospital.Setting: The study was conducted at the outpatient department of the Maluti Adventist Hospital in Mapoteng, Lesotho.Methods: This was a prospective cross-sectional study using consecutive sampling of patients with clinical symptoms of UTI. Midstream urine samples were screened through chemistry and microscopy, then positive urine samples were cultured. The isolated uropathogens underwent antimicrobial susceptibility testing and inclusion continued until 200 culture samples were obtained. Descriptive statistics were used in the data analysis.Results: The top five cultured uropathogens were Escherichia coli (61.5%, Staphylococcus aureus (14%, Pseudomonasspecies (6.5%, Enterococcus faecalis (5.5% and Streptococcus agalactiae (5%. The isolated uropathogens showed low sensitivity to cotrimoxazole (32.5% – 75.0% and amoxicillin (33.2% – 87.5% and high sensitivity to ciprofloxacin (84.0% – 95.1% and nitrofurantoin (76.9% – 100%.Conclusion: In the Maluti setting, cotrimoxazole and amoxicillin should be avoided as first-line drugs for the empirical treatment of community-acquired UTI. We recommend the use of nitrofurantoin as first choice.
George Cosmin Nadas
Full Text Available Introduction: Respiratory disease in calves is an actual problem, a major cause of economic losses due to mortality, growth delay and improper development. These conditions are frequent in calves due to the weaning stress, transport and environmental changes. Aims: The aim of this study was the isolation of bacteria from 30 calves with respiratory disorders and their antibiotic susceptibility testing. Materials and methods: Samples were collected from calves with respiratory disorders (nasal discharge aged 6 to 9 weeks in 2 series, using sterile swabs. Samples were initially inoculated on blood agar and MacConkey agar following the characteristics of the colonies and microscopic examination that enabled the identification of bacterial species. Isolated strains were used to flood Mueller-Hinton agar to carry out sensitivity testing. The antibiotics tested were represented by: Amoxicillin with clavulanic acid, Gentamicin, Florfenicol, Enrofloxacin, Marbofloxacin, Penicillin G, Cefquinone, Tulathromycin, Ceftiofur, Tylosin and Cephalotin. Results: Genus Streptococcus have been identified in 23 samples, followed by Staphylococcus identified in 14 samples, and Bacillus spp., in 10 nasal swabs; The most common bacteria associations were represented by Streptococcus-Staphylococcus, Streptococcus-Staphylococcus-Bacillus, and Streptococcus-E.coli. The most efficient antibiotic was Cefquinome (Cobactan, followed by Penicillin G and Amoxicillin with clavulanic acid (Amoxiclav; the least effective antibiotics were Florfenicol and Tulathromycin. Conclusions: The study carried out on nasal discharge samples collected from calves with respiratory disorders and their antimicrobial profile testing led to the following conclusions: 1 Low susceptibility to Florfenicol is caused by previous treatments when this molecule was excessively used and without prior sensitivity testing. 2 Cefquinome may represent an emergency therapeutic antibiotic for respiratory
Full Text Available Introduction: Urinary tract infections (UTIs affect people worldwide. Escherichia coli is the main agent of UTI, however the etiology may vary according to the age and sex of the patient. Regional variations in the prevalence and antimicrobial resistance should be considered for therapy choice. Objectives: This study aimed to conduct a survey on the main agents of UTI, and assess the resistance of these microorganisms, during the period of March 2010 to June 2012 in the city of Jataí-GO. Method: A retrospective cross-sectional study were performed, collecting data on the prevalence of uropathogens and their sensitivity profiles which were evaluated by disk diffusion method. Results: During this period, 2,181 urine cultures were evaluated, of which 510 (23.4% were positive, predominantly female (81.4% and aged between 21 and 64 years old (59.7%. The most frequently isolated microorganism was E. coli (61%, followed by Staphylococcus saprophyticus (9.4%, and Proteus (9.4%. The prevalence of these bacteria according to the patient sex has suffered a statistically significant change (p < 0.05. It was possible to detect high resistance rate of E. coli to some antibiotics of choice for UTI treatment, such as ampicillin (57.9 %, pipemidic acid (50.5 %, nalidixic acid (48.6 %, and trimethoprim-sulfamethoxazole (44.8%. Conclusion: These data demonstrate the need to know the reality of each region in order to establish an appropriate empirical therapy, when it is not possible to perform culture and antimicrobial susceptibility testing.
Full Text Available This prospective study was carried out over a period of 6 months in the Paediatric Intensive Care Unit (PICU of a tertiary care teaching hospital. The aim of the study was to determine the organisms causing catheter related nosocomial infections in the PICU and to study their antimicrobial susceptibility pattern. Patients with endotracheal intubation, indwelling urinary catheters and central venous catheters (CVC/venous cutdown catheters were included in the study. Colonization of the endotracheal tube, urinary catheter related infections (UCRI and colonization of the CVC/venous cutdown catheters was studied. E. coli was the commonest organism colonizing the endotracheal tube tip with maximum susceptibility to cefotaxime and amikacin. E. coli was also was the commonest organism causing UCRI with maximum susceptibility to nitrofurantoin and amikacin. Acinetobacter was the commonest organism colonizing the CVC/venous cutdown catheters with maximum susceptibility to ciprofloxacin. All these sites of catheter related infections considered together, E. coli and Klebsiella were the commonest nosocomial organisms. Both had maximum susceptibility to amikacin. Methicillin resistant Staphylococcus aureus (MRSA was isolated only from one culture. All the organisms had a poor susceptibility to cefazolin and amoxycillin. A knowledge of the resident microbial flora and their antimicrobial susceptibility pattern is necessary for formulating a rational antibiotic policy in an ICU.
Isabela de Godoy
Full Text Available ABSTRACT: The aim of this study was to determine the prevalence and diversity of veterinary clinical isolates of Staphylococcus and analyze their antimicrobial susceptibility. One hundred Staphylococcus spp. clinical isolates from domestic and wild animals were subjected to partial sequencing of the 16S rRNA gene to species determination. Antimicrobial susceptibility was obtained by a disk diffusion test against six antibiotics: amoxicillin (AMX, cephalexin (LEX, ciprofloxacin (CIP, erythromycin (ERY, gentamicin (GEN and trimethoprim-sulfamethoxazole (SXT. The most common specie was S. pseudintermedius (61%, 61/100 and resistance to ERY (57%, 57/100, SXT (50%, 50/100 and AMX (46%, 46/100 was detected most frequently. In total, 40% (40/100 of Staphylococcus spp. exhibited a multidrug-resistant (MDR phenotype. Results of this study emphasize that animals are reservoir of MDR Staphylococcus spp.
Akoachere Jane-Francis Tatah
Full Text Available Abstract Background Urinary tract infection (UTI represents one of the most common diseases encountered in community medical practice. In resource poor settings, treatment is usually empiric due to the high cost and long duration required for reporting diagnosis by culture and antibiotic susceptibility testing. With the growing problem of drug resistance knowledge of antibiotic susceptibility pattern is pertinent for successful eradication of invading pathogens. Our study, the first of its kind in Cameroon, analyzed the distribution and antibiotic susceptibility of bacteria causing community-acquired urinary tract infection (CAUTI in two towns (Bamenda and Buea with a large number of young and middle aged persons, to provide data that could guide empiric treatment. Findings We cultured 235 urine specimens and analyzed the antibiotic susceptibility of isolates by the disc diffusion technique. Uropathogens were recovered from 137 (58.3%, with prevalence rates in Buea and Bamenda being 65.9% and 54% respectively. Predominant pathogens were Escherichia coli (31.4%, Klebsiella oxytoca (25.5% and Staphylococcus spp (24.1%. Geographic variation in uropathogen distribution and antibiotic susceptibility was observed, and a significant difference in pathogen distribution with respect to gender. The 20–39 years age group had the highest prevalence of infection. All pathogens isolated were detected in this group. Isolates exhibited low susceptibility to antibiotics tested. Bamenda isolates generally exhibited lower susceptibility compared to those from Buea. Conclusion Regional variation in etiology of CAUTI and antibiotic susceptibility observed in our study emphasizes the need to establish local and national antimicrobial resistance monitoring systems in Cameroon to provide information for the development of CAUTI treatment guidelines.
Full Text Available Mastitis in cows, one of the most common and economically important infectious diseases of dairy cattle, all over the world, with significant impact due to economic losses, occurs when the udder becomes inflamed because the leukocytes are released into the mammary gland usually in response to bacteria invasion of the teat canal. The main objective of this study was to evaluate the in vitro antimicrobial susceptibility of bacteria isolated from milk in order to design specific control programs for bovine mastitis in this area. A total of 204 milk samples aseptically collected both from farms and private owners were processed during May 2014 and March 2016 within the Microbiology Laboratory of the Faculty of Veterinary Cluj-Napoca, Romania. The microbiological examination was carried out by inoculation on blood agar and MacConkey medium. After the overnight incubation in aerobic conditions, the identification of the isolates was performed using microscopic, cultural and biochemical methods. Biochemical identification was based on API 20 Biomerieux system. Susceptibility to antibiotics was evaluated using Kirby Bauer disk diffusion method on Mueller-Hinton agar; the antibiotics were represented by Amoxicillin and Clavulanic Acid, Ceftiofur, Florfenicol, Mastidiscs, Enrofloxacin, Penicillin and Tetracycline. Staphylococcus spp. was the most common isolated pathogen, in 54.9% of the specimens, followed by Streptococcus spp. in 20.1%, Escherichia coli in 10.78%, Klebsiella spp. in 8.34%, Bacillus spp. in 5.88%. The most frequent associations were represented by staphylococci-streptococci in 62.7% of the samples, followed by streptococci-bacillus in 19.8% of the samples. The most important etiological agents identified were Staphylococcus aureus, S uberis, Streptococcus agalactiae, and Escherichia coli. Antimicrobial susceptibility test for the total isolates revealed good sensitivity to Enrofloxacin, Mastidiscs and Amoxicillin and Clavulanic Acid
Jian-ping LI; Hai-jian ZHOU; Lin YUAN; Ting HE; Song-hua HU
This study was conducted to determine genetic diversity and antimicrobial susceptibility profiles of Staphylococcusaureus recovered from bovine mastitis in Zhejiang Province, China. Out of 3178 quarter milk samples from 846 lactating cows, among which 459 cows (54.3%) were found HMT positive, 890 quarters (28%) were found having subclinical mastitis. From 75 representative S. aureus isolates, 16 distinct types were identified by pulsed-field gel electrophoresis (PFGE). Four major PFGE types (A, B, C, and D) accounted for 82.7% of all isolates, and type A (41.3%) was observed in multiple herds across the studied areas. Each region was found to have a predominant type: Hangzhou type A (64.1%), Ningbo type C (34.5%) and type B (23.1%), Jinhua type D (53.3%), and Taizhou type C (62.5%). Results of antimicrobial susceptibility tests showed that 90.7% of the isolates were resistant to at least one antimicrobial. Resistance to penicillin and ampicillin (77.3%), tetracycline (60.0%), or erythromycin (48.0%) was observed. The bacteria resistant to multiple antibiotics such as penicillin, ampicillin, tetracycline, and erythromycin were commonly found. The information obtained from this study is useful for designing specific control programs for bovine S. aureus mastiffs in this region.
Full Text Available Acinetobacter baumannii is an aerobic non-motile Gram-negative bacterial pathogen that is resistant to most antibiotics. Carbapenems are the most common antibiotics for the treatment of infections caused by this pathogen. Mechanisms of antibiotic-resistance in A. baumannii are mainly mediated by efflux pumps-lactamases. The aim of this study was to determine antibiotic susceptibility, the possibility of existence of OXAs genes and fingerprinting by Pulsed-Field Gel Electrophoresis (PFGE among clinical isolates of Acinetobacter collected from Kermanshah hospitals.One hundred and four isolates were collected from patients attending Imam Reza, Taleghani and Imam Khomeini hospitals of Kermanshah (Iran. Isolates were identified by biochemical tests and API 20NE kit. The susceptibility to different antibiotics was assessed with Kirby-Bauer disk diffusion method. PCR was performed for detection of bla OXA-23, bla OXA-24, bla OXA-51 and bla OXA-58 beta-lactamase genes. Clonal relatedness was estimated by PFGE (with the restriction enzyme Apa I and DNA patterns were analyzed by Gel compare II 6.5 software.All isolates showed high-level of resistance to imipenem, meropenem as well as to other antimicrobial agents, while no resistance to polymyxin B, colistin, tigecylcine and minocycline was observed. The bla OXA-23like and bla OXA-24 like were found among 77.9% and 19.2% of the isolates, respectively. All isolates were positive for bla OXA-51, but none produced any amplicon for bla OXA-58. PFGE genotype analysis suggested the existence of eight clones among the 104 strains [A (n = 35, B (n = 29, C (n = 19, D (n = 10, E (n = 4, F (n = 3, G (n = 3, H (n = 1]. Clone A was the dominant clone in hospital settings particularly infection wards so that the isolates in this group, compared to the other clones, showed higher levels of resistance to antibiotics.The bla OXA-51-like and bla OXA-23like were the predominant mechanisms of resistance to imipenem in A
Cifuentes-D, Marcela; Silva, Francisco; García, Patricia; Bello, Helia; Briceño, Isabel; Calvo-A, Mario; Labarca, Jaime
Bacteria antimicrobial resistance is an uncontrolled public health problem that progressively increases its magnitude and complexity. The Grupo Colaborativo de Resistencia, formed by a join of experts that represent 39 Chilean health institutions has been concerned with bacteria antimicrobial susceptibility in our country since 2008. In this document we present in vitro bacterial susceptibility accumulated during year 2012 belonging to 28 national health institutions that represent about 36% of hospital discharges in Chile. We consider of major importance to report periodically bacteria susceptibility so to keep the medical community updated to achieve target the empirical antimicrobial therapies and the control measures and prevention of the dissemination of multiresistant strains.
Furlaneto-Maia, Luciana; Rocha, Kátia Real; Siqueira, Vera Lúcia Dias; Furlaneto, Márcia Cristina
Enterococci are increasingly responsible for nosocomial infections worldwide. This study was undertaken to compare the identification and susceptibility profile using an automated MicrosScan system, PCR-based assay and disk diffusion assay of Enterococcus spp. We evaluated 30 clinical isolates of Enterococcus spp. Isolates were identified by MicrosScan system and PCR-based assay. The detection of antibiotic resistance genes (vancomycin, gentamicin, tetracycline and erythromycin) was also determined by PCR. Antimicrobial susceptibilities to vancomycin (30 µg), gentamicin (120 µg), tetracycline (30 µg) and erythromycin (15 µg) were tested by the automated system and disk diffusion method, and were interpreted according to the criteria recommended in CLSI guidelines. Concerning Enterococcus identification the general agreement between data obtained by the PCR method and by the automatic system was 90.0% (27/30). For all isolates of E. faecium and E. faecalis we observed 100% agreement. Resistance frequencies were higher in E. faecium than E. faecalis. The resistance rates obtained were higher for erythromycin (86.7%), vancomycin (80.0%), tetracycline (43.35) and gentamicin (33.3%). The correlation between disk diffusion and automation revealed an agreement for the majority of the antibiotics with category agreement rates of > 80%. The PCR-based assay, the van(A) gene was detected in 100% of vancomycin resistant enterococci. This assay is simple to conduct and reliable in the identification of clinically relevant enterococci. The data obtained reinforced the need for an improvement of the automated system to identify some enterococci.
Full Text Available Enterococci are increasingly responsible for nosocomial infections worldwide. This study was undertaken to compare the identification and susceptibility profile using an automated MicrosScan system, PCR-based assay and disk diffusion assay of Enterococcus spp. We evaluated 30 clinical isolates of Enterococcus spp. Isolates were identified by MicrosScan system and PCR-based assay. The detection of antibiotic resistance genes (vancomycin, gentamicin, tetracycline and erythromycin was also determined by PCR. Antimicrobial susceptibilities to vancomycin (30 µg, gentamicin (120 µg, tetracycline (30 µg and erythromycin (15 µg were tested by the automated system and disk diffusion method, and were interpreted according to the criteria recommended in CLSI guidelines. Concerning Enterococcus identification the general agreement between data obtained by the PCR method and by the automatic system was 90.0% (27/30. For all isolates of E. faecium and E. faecalis we observed 100% agreement. Resistance frequencies were higher in E. faecium than E. faecalis. The resistance rates obtained were higher for erythromycin (86.7%, vancomycin (80.0%, tetracycline (43.35 and gentamicin (33.3%. The correlation between disk diffusion and automation revealed an agreement for the majority of the antibiotics with category agreement rates of > 80%. The PCR-based assay, the van(A gene was detected in 100% of vancomycin resistant enterococci. This assay is simple to conduct and reliable in the identification of clinically relevant enterococci. The data obtained reinforced the need for an improvement of the automated system to identify some enterococci.
Full Text Available The aim of the present study is to investigate the microbiota of root filled teeth with apical periodontitis and to determine the antibiotic susceptibility patterns of microbial strains isolated from twenty nine apical lesion samples taken from patients with fibrous chronic apical lesions. The present study has highlighted the polymicrobial nature of the root canal infections and the importance of facultatively anaerobic, Gram positive bacteria found in 90.74% of the isolated microorganims. The present study has shown an increased resistance of microorganisms to conventional antibiotics, which included penicillin, erythromycin and amoxicillin, as well as tetracyclines, although the last ones have been used sparingly in the past decade. The results of antibiotic sensitivity obtained in this study underline the importance of the microbiological diagnosis and antibiotic susceptibility testing in the choice of therapeutic agents used for the treatment of chronic apical lesions. Further studies with clinical correlation of effectiveness of these antibiotics and cultures taken after administration of antibiotics as well as recording of disappearance of symptoms are also recommended.
Sganga, G; Spanu, T; Bianco, G; Fiori, B; Nure, E; Pepe, G; D'inzeo, T; Lirosi, M C; Frongillo, F; Agnes, S
Liver transplantation (OLT) is a lifesaving procedure for the treatment of many end-stage liver diseases, but infection and acute rejection episodes still remain the main causes of morbidity and mortality. Bloodstream infections (BSIs), particularly, are the major cause of mortality among these patients. BSIs in OLT, are from intra-abdominal, biliary, respiratory, urinary, wound and/or central venous catheter sources. A certain percentage are of unknown origin. Using the computerized database of our microbiology laboratory, we analyzed all BSIs in 75 consecutive adult liver transplant patients in a single center between January 2008 and July 2011. BSIs occurred in 21/75 (28%) patients. Thirteen subjects had a single; two, two episodes, and the other six patients each >4 episodes. All episodes occurred in the first 60 days following OLT; the majority (74%), in the first month. Among 44 microorganisms recovered, 52.3% were gram-negative, the most frequent being Pseudomonas aeruginosa and Klebsiella pneumoniae; 47.7% were gram-positive, the most frequent being coagulase-negative staphylococci, particularly Staphylococcus epidermidis. Overall 65.9% of the isolates were resistant to several antibiotics: 40.9% displayed the multiding-resistant and 25% the panding-resistant phenotype. There was a high incidence of gram-negative and most importantly, resistant bacteria, which required appropriate therapy. These data showed that it is imperative to promote strategies to prevention and contain antimicrobial resistance.
Kishii, Kozue; Kikuchi, Ken; Yoshida, Atsushi; Okuzumi, Katsuko; Uetera, Yushi; Yasuhara, Hiroshi; Moriya, Kyoji
Carbapenem-resistant Acinetobacter baumannii has rapidly spread worldwide. This study investigated antibiotic susceptibility and genotypic resistance of 123 consecutive blood culture isolates of Acinetobacter species collected between 2003 and 2011 in two Japanese hospitals. The isolates were assigned to 13 species. Carbapenem resistance was detected in four isolates. Only one A. baumannii isolate had blaOXA-23 together with ISAba1; the remaining three isolates had IMP-1 metallo-β-lactamase. Quinolone resistance was detected in five isolates that had point mutations in the quinolone resistance-determining region. The predominance of various non-A. baumannii species and low prevalence of carbapenem resistance among blood culture isolates of Acinetobacter species in two Japanese hospitals were confirmed.
Full Text Available Objective: To assess the antimicrobial susceptibility pattern of ESKAPE pathogens from Neyshabur, Iran during 2013–2015. Methods: A total of 345 isolates including 62 Staphylococcus aureus (S. aureus, 38 Enterobacter spp. (including 14 Enterobacter agglomerans, 6 Enterobacter aerogenes and other 18 Enterobacter spp., 123 Enterococcus faecium, 78 Klebsiella pneumonia, 10 Pseudomonas aeruginosa and 34 Acinetobacter baumannii were isolated. The antimicrobial susceptibility pattern of isolates was conducted with Kirby Bauer method. Data were analyzed with SPSS 20.0 software using F- and t-tests. Results: Among S. aureus isolates, the highest resistance was observed against nalidixic acid (81.35% and cefixime (74.50%. Thirty-three (53.22% S. aureus isolates were cefoxitin resistant (methicillin-resistant S. aureus. The majority of Enterobacter species was resistant to amikacin (100.00% and cephalotin (66.60%. Most Enterococcus faecium isolates were resistant to nalidixic acid (89.43% and amikacin (83.33%, but vancomycin-resistant enterococci isolates were not detected. Moreover, among Klebsiella pneumonia, the highest resistance was observed to nalidixic acid (20.98% and cotrimoxazole (28.39%. Furthermore, all Pseudomonas aeruginosa isolates were resistant to cefotaxime (100.00% and majority to nitroforantoin (88.80%. Acinetobacter baumannii isolates showed the highest and the lowest resistance to cefotaxime (100.00% and cefixime (88.71%, respectively. Conclusions: The prevalence of ESKAPE pathogens from northeast region was low, but majority of them exhibited high rate of antibiotic resistance to common used antimicrobial agents.
Full Text Available Deepa Harichandran, Kavitha Radhakrishnan Dinesh Department of Microbiology, Amrita School of Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, Kerala, India Background/purpose: Typhoid and paratyphoid fever continue to be important causes of illness and death in parts of Asia, being associated with poor sanitation and consumption of unsafe food and water. Antimicrobial resistance has emerged to traditional first-line drugs, namely, the fluoroquinolones, as well as to third-generation cephalosporins, posing challenges to treatment. Azithromycin has proven to be an effective alternative for treatment of uncomplicated typhoid fever. The purpose of this study was to determine the antimicrobial susceptibility, clinical outcome and serotype distribution pattern of clinical isolates belonging to Salmonella enterica subspecies enterica. Methodology: All clinical isolates of S. enterica obtained from blood, sterile body fluids, as well as stool and urine samples at Amrita Institute of Medical Sciences and Research Centre, Kerala, India, between August 2011 and July 2013 were included in the study and processed based on standard microbiology protocols. Results: A total of 118 isolates of Salmonella were obtained during the study period. Out of these, 79 were of S. Typhi (66.95%, followed by isolates of S. Paratyphi A (22; 18.64% and S. Typhimurium 12 (10.17%. Five isolates could not be identified further. There was 100% susceptibility to ceftriaxone in all S. enterica subspecies. Ciprofloxacin susceptibility was 32.91% for S. Typhi and 40.90% for S. Paratyphi A as determined by the disk diffusion method. The susceptibility profile of S. Typhi isolates to different antimicrobials was as follows: chloramphenicol (94.93%, ampicillin (77.21%, cotrimoxazole (75.94% and azithromycin (78.48%. For S. Typhi, the minimum inhibitory concentration (MIC of ciprofloxacin required to inhibit the growth
Beier, Ross C; Franz, Eelco; Bono, James L; Mandrell, Robert E; Fratamico, Pina M; Callaway, Todd R; Andrews, Kathleen; Poole, Toni L; Crippen, Tawni L; Sheffield, Cynthia L; Anderson, Robin C; Nisbet, David J
The disinfectant and antimicrobial susceptibility profiles of 138 non-O157 Shiga toxin-producing Escherichia coli strains (STECs) from food animals and humans were determined. Antimicrobial resistance (AMR) was moderate (39.1% of strains) in response to 15 antimicrobial agents. Animal strains had a lower AMR prevalence (35.6%) than did human strains (43.9%) but a higher prevalence of the resistance profile GEN-KAN-TET. A decreasing prevalence of AMR was found among animal strains from serogroups O45 > O145 > O121 > O111 > O26 > O103 and among human strains from serogroups O145 > O103 > O26 > O111 > O121 > O45. One animal strain from serogroups O121 and O145 and one human strain from serogroup O26 had extensive drug resistance. A high prevalence of AMR in animal O45 and O121 strains and no resistance or a low prevalence of resistance in human strains from these serogroups suggests a source other than food animals for human exposure to these strains. Among the 24 disinfectants evaluated, all strains were susceptible to triclosan. Animal strains had a higher prevalence of resistance to chlorhexidine than did human strains. Both animal and human strains had a similar low prevalence of low-level benzalkonium chloride resistance, and animal and human strains had similar susceptibility profiles for most other disinfectants. Benzyldimethylammonium chlorides and C10AC were the primary active components in disinfectants DC&R and P-128, respectively, against non-O157 STECs. A disinfectant FS512 MIC ≥ 8 μg/ml was more prevalent among animal O121 strains (61.5%) than among human O121 strains (25%), which may also suggest a source of human exposure to STEC O121 other than food animals. Bacterial inhibition was not dependent solely on pH but was correlated with the presence of dissociated organic acid species and some undissociated acids.
Moon, Hee-Won; Kim, Hyun Jung; Hur, Mina; Yun, Yeo-Min
We performed a comprehensive analysis on 3,594 Staphylococcus aureus isolates from routine culture during the last 4 years. The antimicrobial susceptibilities of the isolates were analyzed according to their origin and were compared based on the type of specimens. The proportion of methicillin-resistant Staphylococcus aureus (MRSA) in community-associated (CA), health care-associated, community onset (HACO), and health care-associated (HA) isolates were 33.0%, 54.3%, and 73.3%, respectively. The MRSA rate differed significantly between specimens, with the highest rate from urine in the CA and HACO isolates, whereas the highest rate from the respiratory tract was in the HA isolates. The monitoring of the MRSA rate in CA, HACO, and HA S aureus isolates would be valuable for surveillance. The elevated rates of MRSA in urinary specimens from CA and HCA isolates need to be addressed for infection control.
Talita Gomes Baêta Lourenço
Full Text Available This study evaluates the antimicrobial susceptibility and composition of subgingival biofilms in generalized aggressive periodontitis (GAP patients treated using mechanical/antimicrobial therapies, including chlorhexidine (CHX, amoxicillin (AMX and metronidazole (MET. GAP patients allocated to the placebo (C, n = 15 or test group (T, n = 16 received full-mouth disinfection with CHX, scaling and root planning, and systemic AMX (500 mg/MET (250 mg or placebos. Subgingival plaque samples were obtained at baseline, 3, 6, 9 and 12 months post-therapy from 3–4 periodontal pockets, and the samples were pooled and cultivated under anaerobic conditions. The minimum inhibitory concentrations (MICs of AMX, MET and CHX were assessed using the microdilution method. Bacterial species present in the cultivated biofilm were identified by checkerboard DNA-DNA hybridization. At baseline, no differences in the MICs between groups were observed for the 3 antimicrobials. In the T group, significant increases in the MICs of CHX (p < 0.05 and AMX (p < 0.01 were detected during the first 3 months; however, the MIC of MET decreased at 12 months (p < 0.05. For several species, the MICs significantly changed over time in both groups, i.e., Streptococci MICs tended to increase, while for several periodontal pathogens, the MICs diminished. A transitory increase in the MIC of the subgingival biofilm to AMX and CHX was observed in GAP patients treated using enhanced mechanical therapy with topical CHX and systemic AMX/MET. Both protocols presented limited effects on the cultivable subgingival microbiota.
Kanayama, Akiko; Kobayashi, Intetsu; Shibuya, Kazutoshi
Here we report on the prevalence of extended-spectrum β-lactamase (ESBL)-producing Proteus mirabilis from a nationwide antimicrobial resistance survey in different geographical regions of Japan. A total of 799 P. mirabilis isolates recovered between July 2009 and June 2010 from 314 healthcare facilities were characterised according to ESBL production, source, location and antimicrobial susceptibility pattern. ESBL production was found in 364 (45.6%) of the isolates, among which 354 (97.3%) produced CTX-M-2 group β-lactamases. Of the 349 ESBL-producing isolates in which the inpatient or outpatient status of the source was known, 324 (92.8%) were from inpatients and 25 (7.2%) were from outpatients (PESBL-producers generated a distribution of PFGE patterns into 21 groups. Genetic relatedness was seen among isolates within a region, which is consistent with horizontal transmission. With respect to the frequency of ESBL-producers by specimen source, 12/14 (85.7%) central venous catheter specimens yielded ESBL-producing P. mirabilis compared with 159/405 (39.3%), 119/209 (56.9%), 42/77 (54.5%) and 20/49 (40.8%), respectively, for isolates from urine, sputum, decubitus ulcer and wound specimens. Among the ESBL-producers, non-susceptibility to ciprofloxacin was found in 74.2% of the ESBL-producing isolates compared with 17.7% of the ESBL-non-producing isolates. These results show that approximately one-half of the P. mirabilis isolates from clinical specimens in Japan are ESBL-producers and that the potential for concomitant fluoroquinolone resistance must also be considered.
Souto, Monalisa S M; Coura, Fernanda M; Dorneles, Elaine M S; Stynen, Ana Paula R; Alves, Telma M; Santana, Jordana Almeida; Pauletti, Rebeca B; Guedes, Roberto M C; Viott, Aline M; Heinemann, Marcos B; Lage, Andrey P
The aims of the present study were to determine (i) the profiles of phylogroup and (ii) the antimicrobial susceptibility of pathogenic Escherichia coli strains isolated from calves, and of Salmonella spp. strains isolated from calves and pigs in Minas Gerais State, Brazil. Sixty-one pathogenic E. coli strains and Salmonella spp. (n = 24) strains isolated from fecal samples of calves and Salmonella spp. (n = 39) strains previously isolated from fecal samples of growing/finishing pigs were tested. The minimum inhibitory concentration (MIC) using the agar dilution method was determined for nalidixic acid, amikacin, amoxicillin, ampicillin, cefoxitin, norfloxacin, gentamicin, tetracycline, and trimethoprim-sulfamethoxazole. All E. coli isolates were susceptible to amikacin. Tetracycline was the antimicrobial that presented the higher frequency of resistance among E. coli strains, followed by ampicillin, trimethoprim-sulfamethoxazole, amoxicillin, nalidixic acid, norfloxacin, gentamicin, and cefoxitin. E. coli (n = 61) strains isolated from calves belonged to different phylogroup namely, phylogroup A (n = 26), phylogroup B1 (n = 31), phylogroup E (n = 3), and phylogroup F (n = 1). Phylogroups B2, C, and D were not identified among the E. coli in the present study. All Salmonella spp. (n = 24) strains isolated from fecal samples of calves were susceptible to amikacin, amoxicillin, ampicillin, norfloxacin, gentamicin, tetracycline, and trimethoprim-sulfamethoxazole. Resistance to nalidixic acid and cefoxitin was detected in 16.66 and 8.33 % of the Salmonella spp. strains, respectively. Among the Salmonella spp. (n = 39) strains isolated from fecal samples of pigs, the higher frequency of resistance was observed to tetracycline, followed by amoxicillin, gentamicin, ampicillin, trimethoprim-sulfamethoxazole, nalidixic acid, cefoxitin, and norfloxacin. All strains were susceptible to amikacin. Forty-eight (78.68 %) of the E. coli strains
Full Text Available Background: This study was conducted to know the rate of prevalence of community acquired UTI infections in both males and females, Assam, North-East India. Materials and Methods: A 50 μl of urine sample from each of the subjects was streaked on cystine lactose electrolyte-deficient agar medium. The plates were incubated overnight at 37°C. Pure, isolated colonies of each type was separately cultured and characterized. The susceptibility of the clinical isolates to routinely prescribed antibiotics in the hospital was performed against various antibiotics. Results: Of the total 40 patients, 26 positive samples were obtained of which 19 females (73.07% and 7 male (26.92% patients were shown to be urine culture positive. The most commonly isolated bacterium was Escherichia coli with a frequency rate of (33.3% followed by Staphyloccous aureus (22.2%, Klebsiella pnemoniae (11.1%, coagulase negative Staphylococcus (CoNS (7.4%, Pseudomonas sp. (7.4%, Proteus myxofaciens (3.7%, Proteus mirabilis (3.7%, Edwardsiella tarda (3.7%, Morganella morganii (3.7%, and Citrobacter fruendii (3.7%. Analysis of the samples showed that UTI was more common in females of younger age group as compared with males. It was also observed that the patients responded effectively to imepenem (IE, cepefime, amikacin, norfloxacin, and co-trimoxazole antimicrobial agents against Gram-negative bacilli. Furthermore, the most effective antibiotics against Gram-positive cocci was found to be ampicillin, ciprofloxacin, IE, and penicillin G (benzyl penicillin. Conclusions: Antibiotics have been in use for a long period and more often the misuse of antimicrobial drugs has today led to a general rise in the emergence of resistant bacteria.
Profile of antimicrobial susceptibility isolated microorganisms from hospitalized patients in PICU ward and detection of Methicillin-resistant Staphylococcus aureus and ESBL-producing bacteria by phenotypic methods
Shahla Abbas Poor
Full Text Available Background: Hospital-acquired infections are a major challenge to patient. A range of gram-negative organisms are responsible for hospital-acquired infections, the Enterobacteriaceae family being the most commonly identified group overall. Infections by ESBL producers are associated with severe adverse clinical outcomes that have led to increased mortality, prolonged hospitalization, and rising medical costs. The aim of this study was to survey profile of antimicrobial susceptibility isolated microorganisms from hospitalized patients in PICU ward and detection of methicillin-resistant Staphylococcus aureus and ESBL-producing bacteria by phenotypic methods. Material and Methods: In this study participants were patients hospitalized in PICU part of Bahrami Hospital, Tehran, with attention to involved organ. For isolation of bacteria from patient’s samples, culture performed on different selective and differential media. After confirmation of bacteria by biochemical tests, susceptibility testing was performed by disc diffusion method. Phenotypic detection of MRSA strains was performed using cefoxcitin disc. ESBL producing strains were detected by ceftazidime (CAZ and ceftazidime/clavulanic acid (CAZ/CLA discs. Results: Among all isolated organisms from clinical samples, the most common isolated organisms were Escherichia coli (24 cases, Pseudomonas areoginosa (9 cases and Staphylococcus aureus (8 cases, respectively. Among eight MRSA isolated strains from different clinical samples, six strains (75% were MRSA. Among 52 isolated gram negative organisms, 5 strains (9/6% were ESBL. Conclusion: Standard interventions to prevent the transmission of antimicrobial resistance in health care facilities include hand hygiene, using barrier precautions in the care of colonized and infected patients, using dedicated instruments and equipment for these patients. The colonized or infected patients should be isolated in single rooms, multibed rooms or areas
Fredborg, Marlene; Andersen, Klaus R; Jørgensen, Erik;
Rapid antibiotic susceptibility testing is in highly demand in health-care fields as antimicrobial resistant bacterial strains emerge and spread. Here we describe an optical screening system (oCelloScope), which based on time-lapse imaging of 96 bacteria-antibiotic combinations at a time, introdu......Rapid antibiotic susceptibility testing is in highly demand in health-care fields as antimicrobial resistant bacterial strains emerge and spread. Here we describe an optical screening system (oCelloScope), which based on time-lapse imaging of 96 bacteria-antibiotic combinations at a time......, introduces real-time detection of bacterial growth and antimicrobial susceptibility, with imaging material to support the automatically generated graphs. Automated antibiotic susceptibility tests of a monoculture showed statistically significant antibiotic effect within 6 minutes and within 30 minutes...
Full Text Available Microbial drug resistance is a major problem in the treatment of infectious diseases worldwide. The purpose of this survey is to determine the prevalence of the type of bacterial agents that cause urinary infection and to assess the antimicrobial sensitivity pattern in the Urmia Medical University, Iran. In the period between 2005 and 2006, urine cultures collected were analyzed. Positive culture was defined as growth of a single bacterial species with colony count of > 100,000 CFU/mL. Stratification was done according to age-group and gender. Statistical tests used included chi-square to evaluate differences between susceptibility rates. A total of 803 urine culture positive patients were studied of whom 81.6% were females and 18.4% were males. The common micro-organisms isolated were E. coli (78.58%, Klebsiella (5.48%, Proteus and Staphylococcus. About 89% of the E. coli isolated showed sensitivity to cephtizoxin, 83.9% to gentamycin and 83.2% to ciprofloxacin; the highest resistance was shown to ampicillin and co-trimoxazole. Surveys of this nature will give a clear idea about the bacteriologic profile in a given institution as well their antibiotic sensitivity profile. This will act as a guide to commencing empirical antibiotic treatment in patients with urinary infections until such time culture reports are available.
Garedew, Legesse; Hagos, Zenabu; Zegeye, Bidir; Addis, Zelalem
Food borne pathogens are major causes of deaths, illnesses and billions of dollars of expenses. The burden of food borne illness is worsened by the ever increasing rate of antimicrobial resistance microbes. Shigella, a bacterial pathogen associated with food, is reported to account for higher prevalence rates of food borne illness in different settings. A cross-sectional study was conducted from February 10 to June 30, 2013, at the butcher houses of Gondar town in the Northwest of Ethiopia to assess the prevalence and antimicrobial susceptibility pattern of Shigella. Cattle raw meat and swab samples from selected critical control points, including knives, chopping boards, and the hands and noses of butchers, were collected and analyzed. The identification of Shigella was carried out using colony characteristics, the Gram reaction, and biochemical tests. Antimicrobial susceptibility testing was performed using the Kirby-Bauer disc diffusion method. The overall hygienic status of the butcher shops was also assessed using a checklist. An observational analysis revealed that the sanitary condition of the butcher shops and their premises was poor. Of 306 samples screened, 10.5% were positive for Shigella. Approximately 7.4% of meat samples and 10.2% of swab samples were contaminated with Shigella. Out of the total Shigella isolates, 90.6%, 46.9%, 18.8% and 9.4% were resistant to ampicillin, amoxicillin, ceftriaxone and tetracycline, respectively. A multidrug resistance pattern was recorded in 27.8% of the isolates. In conclusion, the safety of meat sold at Gondar butchers houses was poor. The identified Shigella isolates showed high levels of drug resistance and multidrug resistance patterns for commonly used antimicrobials in veterinary and human medicine. Practicing wise use of antimicrobials and strict sanitary interventions at different critical control points is strongly recommended, in addition to further in-depth studies to prevent unprecedented consequences from
Bygdeman, S M; Mårdh, P A
The determination of the minimal growth-inhibiting concentration (MIC), the minimal metabolism-inhibiting concentration (MMC), and the minimal mycoplasmacidal concentration (MCC) of various antimicrobial compounds for Mycoplasma hominis is influenced by the pH of the test media, the inoculum size, and the incubation time, although each of these factors generally do not affect the minimal concentration more than fourfold. M. hominis is resistant to beta-lactam antibiotics, vancomycin, sulfonamides, trimethoprim, and polymyxin B. There are great differences in the susceptibility of M. hominis to various macrolide antibiotics. Thus the organism is resistant to erythromycin and oleandomycin, moderately resistant to tylosin and spiramycin, susceptible to josamycin as well as to another macrolide drug, labelled M-4365G. M. hominis is also highly susceptible to the macrolide-like compound rosaramicin and to the tetracyclines (although resistant strains occur). It is susceptible to lincomycin and clindamycin, and moderately susceptible to chloramphenicol and rifampicin. The aminoglycosides have limited activity against M. hominis.
Rivas-Santiago, Bruno; Serrano, Carmen J.; Enciso-Moreno, J. Antonio
In the last few years, the great impact of antimicrobial peptides on infectious disease susceptibility and natural resistance has been reported. In some cases, susceptibility to diseases is related to antimicrobial peptide polymorphisms and gene copy numbers, but for the vast majority of infectious diseases, these phenomena need to be elucidated. This review is focused on the current knowledge about susceptibility and resistance conferred by genetic variations in antimicrobial peptide expression in infectious diseases. PMID:19703980
Rivas-Santiago, Bruno; Serrano, Carmen J; Enciso-Moreno, J Antonio
In the last few years, the great impact of antimicrobial peptides on infectious disease susceptibility and natural resistance has been reported. In some cases, susceptibility to diseases is related to antimicrobial peptide polymorphisms and gene copy numbers, but for the vast majority of infectious diseases, these phenomena need to be elucidated. This review is focused on the current knowledge about susceptibility and resistance conferred by genetic variations in antimicrobial peptide expression in infectious diseases.
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.
Cojutti, Piergiorgio; Scarparo, Claudio; Sartor, Assunta; Coato, Paola; Rigoli, Roberto; Pea, Federico
A 5-year survey (2009-2013) of antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients with bloodstream infections was carried out in Northeast Italy. No upward creep of glycopeptides MICs was documented among 582 nonduplicate MRSA blood isolates, which were tested in accordance with broth microdilution and interpreted in accordance with EUCAST recommendations. Teicoplanin showed stably a lower MIC50 in comparison with vancomycin (0.25-0.5 versus 1 mg/L). The activities of newer anti-MRSA antibacterials stratified by glycopeptides MICs showed similar trends in MICs of either vancomycin or teicoplanin with those of daptomycin, linezolid, and tigecycline. We hypothesize that in centers with different distribution of glycopeptides MICs, downward for teicoplanin and upward for vancomycin, teicoplanin could be a more effective alternative to vancomycin for empirical treatment of MRSA-related bacteremia.
Lupetti, A; Barnini, S; Morici, P; Ghelardi, E; Nibbering, P H; Campa, M
The rapid identification and antimicrobial susceptibility testing (AST) of bacteria in clinical blood cultures is crucial to optimise antimicrobial therapy. A previous study involving small sample numbers revealed that the addition of saponin to blood cultures, further referred to as the new method, shortened considerably the turn-around time for the identification and AST of Gram-positive cocci as compared to the current method involving an overnight subculture. Here, we extend previous results and compare the identification and AST of blood cultures containing Gram-negative bacilli by the new and current methods. The identification and AST of 121 Gram-positive and 109 Gram-negative bacteria in clinical monomicrobial blood cultures by the new and current methods and, in the case of Gram-negative bacilli, by direct (no additions) inoculation into an automated system (rapid method) was assessed using the Vitek 2 system. Discrepancies between the results obtained with the different methods were solved by manual methods. The new method correctly identified 88 % of Gram-positive and 98 % of Gram-negative bacteria, and the rapid method correctly identified 94 % of Gram-negative bacteria. The AST for all antimicrobials by the new method were concordant with the current method for 55 % and correct for an additional 9 % of Gram-positive bacteria, and concordant with the current method for 62 % and correct for an additional 21 % of Gram-negative bacilli. The AST by the rapid method was concordant with the current method for 62 % and correct for an additional 12 % of Gram-negative bacilli. Together, saponin-treated monomicrobial blood cultures allow rapid and reliable identification and AST of Gram-positive and Gram-negative bacteria.
Lob, Sibylle H; Hoban, Daryl J; Sahm, Daniel F; Badal, Robert E
Acinetobacter baumannii, although representing a small percentage of Gram-negative bacilli isolates in intra-abdominal infections (IAIs) and urinary tract infections (UTIs), is frequently multidrug-resistant (MDR) and can pose difficult therapeutic challenges. From 2011 to 2014, 2337 A. baumannii were collected from IAIs and UTIs at 453 hospital sites in 48 countries as part of the SMART ongoing surveillance initiative. Current susceptibility and multidrug resistance, defined as resistance to at least three of the tested drug classes, were determined in a subset of 1011 isolates from 2013 to 2014. A. baumannii comprised 0.7-4.6% of all aerobic and facultative Gram-negative bacilli isolated in six global regions. MDR rates were lowest in North America (47%) and highest in Europe and the Middle East (>93%), with higher rates in ICUs than in non-ICU wards in almost all regions. Antimicrobial susceptibility profiles varied by region but resistance was high everywhere, with no drug inhibiting >70% of A. baumannii isolates in any region. Susceptibility to imipenem was highest in North America (64%) and lowest in Europe and the Middle East (≤11%). Amikacin overall was the most active of the studied agents, including against MDR isolates (of which 11-38% were susceptible). Trend analysis of only those countries that contributed isolates in each study year (2011-2014) demonstrated an increasing trend in MDR rates in the Middle East as well as decreasing susceptibility to several single antimicrobial agents in Africa, Europe and the Middle East. These patterns and trends can help direct antimicrobial therapy and infection control efforts.
Antimicrobial susceptibility profiles, serotype distribution and virulence determinants among invasive, non-invasive and colonizing Streptococcus agalactiae (group B streptococcus) from Malaysian patients.
Eskandarian, N; Ismail, Z; Neela, V; van Belkum, A; Desa, M N M; Amin Nordin, S
A total of 103 group B streptococci (GBS) including 22 invasive, 21 non-invasive, and 60 colonizing isolates were collected in a Malaysian hospital (June 2010-October 2011). Isolates were characterized by conventional and molecular serotyping and analyzed for scpB, lmb, hylB, cylE, bac, bca and rib gene content. Antimicrobial susceptibility to penicillins, macrolides, lincosamides, quinolones and tetracyclines was determined using disk diffusion and the MICs for penicillin were determined by E-test. Molecular serotyping for all eight serotypes (Ia, Ib, II-VII) was in full accordance with conventional serotyping. Overall, taking CS and MS together, serotype VI was the most common capsular type (22.3 %) followed by VII (21.4 %), III (20.4 %), Ia (17.5 %), V (9.7 %), II (7.7 %) and IV (1 %). Susceptibility to beta-lactam antimicrobials was prevalent (100 %). Resistance rates for erythromycin, clindamycin and tetracycline were 23.3 %, 17.5 % and 71.8 %, respectively. PCR-virulence gene screening showed the presence of cylE, lmb, scpB and hylB in almost all the isolates while rib, bca, and bac genes were found in 29.1 %, 14.6 % and 9.7 % of the isolates. Certain genes were significantly associated with specific serotypes, namely, rib with serotypes Ia, II, III and VI; bca and bac with serotypes II and III. Furthermore, serotype Ia was significantly more common among patients with invasive infections (p < 0.01) and serotype VI isolates were significantly more common among carriers (p < 0.05). In summary, serotype distribution correlates with virulence gene content will be useful in epidemiological studies and design of vaccines.
[Consensus for antimicrobial susceptibility testing for Enterobacteriaceae. Subcommittee on Antimicrobials, SADEBAC (Argentinian Society of Clinical Bacteriology), Argentinian Association of Microbiology].
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
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.
Hammer, Timo R; Mucha, Helmut; Hoefer, Dirk
Dermatophytoses are a widespread problem worldwide. Textiles in contact with infected skin can serve as a carrier for fungus propagation. Hitherto, it is unknown, whether antifungal textiles could contribute in controlling dermatophytes e.g. by disrupting the chain of infection. Testing of antimicrobial fabrics for their antifungal activities therefore is a fundamental prerequisite to assess the putative clinical relevance of textiles for dermatophyte prevention. Fabrics finished with either didecyldimethylammonium chloride (DDAC), poly-hexamethylenbiguanide, copper and two silver chloride concentrations were tested for their antifungal activity against Trichophyton rubrum, Trichophyton mentagrophytes and Candida albicans. To prove dermatophyte susceptibility towards the textiles, swatches were subjected to DIN EN 14199 (Trichophyton sp.) or DIN EN ISO 20743 (C. albicans) respectively. In addition, samples were embedded, and semi-thin sections were analysed microscopically. While all samples showed a clear inhibition of C. albicans, activity against Trichophyton sp. varied significantly: For example, DDAC completely inhibited T. rubrum growth, whereas T. mentagrophytes growth remained unaffected even in direct contact to the fibres. The results favour to add T. mentagrophytes as a test organism in textile dermatophyte efficacy tests. Microscopic analysis of swatches allowed detailed evaluation of additional parameters like mycelium thickness, density and hyphae penetration depth into the fabric.
Khelaifia, S; Drancourt, M
We herein review the state of knowledge regarding the in vitro and in vivo susceptibility of archaea to antimicrobial agents, including some new molecules. Indeed, some archaea colonizing the human microbiota have been implicated in diseases such as periodontopathy. Archaea are characterized by their broad-spectrum resistance to antimicrobial agents. In particular, their cell wall lacks peptidoglycan, making them resistant to antimicrobial agents interfering with peptidoglycan biosynthesis. Archaea are, however, susceptible to the protein synthesis inhibitor fusidic acid and imidazole derivatives. Also, squalamine, an antimicrobial agent acting on the cell wall, proved effective against human methanogenic archaea. In vitro susceptibility data could be used to design protocols for the decontamination of complex microbiota and the selective isolation of archaea in anaerobic culture.
Samonis, G.; Ho, D H; Gooch, G F; Rolston, K V; Bodey, G P
The in vitro activities of 16 antimicrobial agents against 14 clinical isolates of Citrobacter diversus and 27 isolates of Citrobacter freundii were studied. C. freundii isolates were more resistant, being susceptible only to amikacin, netilmicin, gentamicin, imipenem, ciprofloxacin, and enoxacin. C. diversus isolates were susceptible to many more of the agents tested.
Adalva Lopes Machado
The marketing of fish has shown substantial increase; however, their place of origin and ways of handling and storage may pose health risk. The microorganisms in the food chain and in capture environments cause concern over the risk of disease transmission and the multiple resistance to several drugs. This study aimed at characterizing the antimicrobial resistance of 191 strains of Escherichia coli isolated from 20 fish samples, ten saltwater samples: (5) mackerel (S. cavalla) and (5) snapper...
Perfil de susceptibilidade a antimicrobianos em amostras de cocos Gram-positivos, catalase negativos, isoladas de mastite subclínica bubalina Profile of antimicrobial susceptibility in strains of Gram positive cocos, negative catalase, isolated from buffalo subclinical mastitis
Maria C.E. Vianni
the State of Rio de Janeiro. The test used was diffusion of disks in agar Müller Hinton, according to recommendations of the National Committee for Clinical Laboratory Standards - NCCLS. There were tested disks with ampicillin (10mg, cefalotin (30mg, cefotaxime (30mg, cefoxitin (30mg, cloranfenicol (30mg, eritromycin (15mg, gentamycin (10mg, nitrofurantoin (300mg, norfloxacin (10mg, penicillin (10 IU, tetracyclin (30mg and vancomycin (30mg. The results showed that with Lactococcus garvieae, the most efficient antimicrobial was nitrofurantoin, revealing 85.71% sensibility, followed by cefotaxime (61.90%, vancomycin (52.38%, norfloxacin (47.62& and cefalotin (47.62%. The highest resistance was developed against penicillin and ampicillin, with 95.24% resistance for the two antimicrobials. The susceptibility profile developed by the strains of Enterococcus gallinarum showed low sensibility against the tested antimicrobials; the highest resistance observed was against eritromycin and gentamycin, with 33.34% sensibility for both. The antimicrobial evaluation showed 100% resistance against vancomycin and tetracyclin, followed by cloranfenicol, penicillin, ampicillin, cefoxitin, cefotaxim, norfloxacin and nitrofurantoin; all of them showed a resistance of 83.33% with the samples tested.
Jousimies-Somer, H; Pyörälä, S.; Kanervo, A
The susceptibility to 9 antimicrobial agents of 32 aerobic bacterial isolates and to 10 antimicrobial agents of 37 anaerobic bacterial isolates from 23 cases of bovine summer mastitis (16 Actinomyces pyogenes isolates, 8 Streptococcus dysgalactiae isolates, 3 S. uberis isolates, 3 S. acidominimus isolates, 2 Streptococcus spp., 15 Peptostreptococcus indolicus isolates, 10 Fusobacterium necrophorum isolates, and 12 isolates of anaerobic gram-negative rods) was determined by the agar dilution m...
Zmudzki, J; Szczotka, A; Nowak, A; Strzelecka, H; Grzesiak, A; Pejsak, Z
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 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.
Etiology, antimicrobial susceptibility profile and epidemiological aspects in canine otitis: a retrospective study of 616 casesEtiologia, perfil de sensibilidade aos antimicrobianos e aspectos epidemiológicos na otite canina: estudo retrospectivo de 616 casos
Verônica Baldim de Oliveira
Full Text Available A retrospective study of etiology, antimicrobial susceptibility profile and multiple drug resistance, and major epidemiological aspects were investigated in 616 cases of canine otitis. Staphylococcus ? hemolitic (26.27%, Malassezia pachydermatis (12.35%, and Pseudomonas aeruginosa (8.8% were the most common microorganisms identified. The isolates were susceptible mainly to norfloxacin (89.62%, gentamicin (83.25%, and ofloxacin (80.16%. High occurrence of resistance of isolates was observed to neomicin (30.84% and cephalexin (27.63%. Multiple drug resistance to three or more and five or more of antimicrobials tested was observed in 34.9% and 15.5% of isolates, respectively. The cases of canine otitis occurred predominantly in first years of age, in mixed breeds animals, at autumn season. The presence of itch, bad smell, and secretion in ear conduct were the major signs observed at clinical examination. Estudo retrospectivo da etiologia, perfil de sensibilidade microbiana, ocorrência de multirresistência dos isolados e os principais aspectos epidemiológicos foram investigados em 616 casos de otite canina. Staphylococcus ? hemolítico (26,27%, Malassezia pachydermatis (12,35% e Pseudomonas aeruginosa (8,8% foram os micro-organismos mais frequentes. Os isolados foram sensíveis “in vitro” principalmente a norfloxacina (89,62%, gentamicina (83,25% e ofloxacina (80,16%. Alta ocorrência de resistência das linhagens foi observada frente à neomicina (30,84% e cefalexina (27,63%. A ocorrência de resistência múltipla a três ou mais e cinco ou mais dos antimicrobianos foi observada em, respectivamente, 34,9% e 15,5% dos isolados. Os casos ocorreram predominantemente nos primeiros anos de idade, em animais sem raça definida, no período do outono. A presença de prurido, mau cheiro e secreção no conduto auditivo foram os principais sinais observados ao exame clínico.
Breteler, K.B.; Rentenaar, R.J.; Verkaart, G.; Sturm, P.D.J.
BACKGROUND: Urinary tract infections (UTIs) are common infections in the community and the hospital. With increasing antimicrobial resistance, specifically in the Gram-negative uropathogens, reliable, rapid antimicrobial susceptibility data would be useful to guide antimicrobial treatment. Direct an
Rafael Antonio Casarin Penha Filho
Full Text Available ABSTRACT: Salmonella Gallinarum (S. Gallinarum and Salmonella Pullorum (S. Pullorum are poultry host-specific, agents of fowl typhoid and pullorum disease, respectively. These biovars cause septicemic infections, resulting in high mortality. Outbreaks are frequently reported worldwide, causing losses due to the elimination of infected flocks and treatments. The use of antimicrobial agents is frequent in poultry farms to prevent or treat gastrointestinal infections. In the present research it was evaluated the antimicrobial susceptibility of 50 S. Gallinarum and S. Pullorum isolates, from outbreaks that occurred between 1987 to 1991 and 2006 to 2013. The comparison of the susceptibility profiles showed that all isolates were susceptible to β-lactams. All isolates from 1987-1991 were susceptible to all antibiotics tested except NAL and CIP (78%. The susceptibility profile of S. Gallinarum (2006 - 2013 period was the following NAL (58%, CIP (63%, ENR (67%, TET (92%, FFC (96% and SXT (96%. S. Pullorum isolates (2006 - 2013 period showed the following susceptibility rates to NAL (65%, CIP (71%, ENR (94% and TET (94%. All isolates were susceptible to β-lactams tested, however, resistance to quinolones and fluoroquinolones increased over time. Furthermore, low levels of resistance to other antibiotics were found in recent isolates, such as tetracyclines.
Jombo GTA; Akpan S; Epoke J; Denen Akaa P; Eyong KI; Gyuse AN
Objective:To ascertain the antibiotic susceptibility patterns ofEscherichia coli recovered from blood culture specimens in Calabar, Nigeria.Methods: The study was retrospective in nature and was carried out at University of Calabar Teaching Hospital(UCTH)Calabar. Data generated from blood culture specimens over a five year period (Feb.2004-Feb.2009) was compiled, relevant information such as age, sex, organism recovered and antibiotic susceptibility patterns were obtained from patients records. Samples were collected, transported, stored and processed using standard laboratory procedures. Data obtained was analysed using Epi Info6 statistical software.Results:Escherichia coli was responsible for15.3% (31/203) of the blood infections being the third most common microorganism encountered. The community acquired(CA) isolates of the organism were significantly less resistant (P0.05). Majority(>95.0%) of theNC isolates ofEscherichia coli were resistant to six of the antibiotics tested.Conclusions: Control mechanisms for hospital acquired infections should be stepped up so as to limit the spread of the highly resistant bacterial strains. Also the sale and consumption of antibiotics by the public need to be regulated.
Saderi; Sadat Hosseini; Moosavi; Sahebnasagh; Boroumandii
Background Enterococci are one of the most common nosocomial pathogens and the emergence of multidrug-resistant strains has been increasing. Objectives We studied the antimicrobial susceptibility of enterococci isolated from different clinical specimens of patients in Tehran. Materials and Methods From the beginning of April 2013 to the end of June 2013, a total of 146 enterococci ...
Full Text Available Background Enterococci are one of the most common nosocomial pathogens and the emergence of multidrug-resistant strains has been increasing. Objectives We studied the antimicrobial susceptibility of enterococci isolated from different clinical specimens of patients in Tehran. Materials and Methods From the beginning of April 2013 to the end of June 2013, a total of 146 enterococci were isolated from the Pars General Hospital in Tehran. The antimicrobial susceptibility pattern of the isolates against ampicillin, clindamaycin, ciprofloxacin, erythromycin, levofloxacin, linezolid, nitrofurantoin, tetracycline, and vancomycin was determined using the disk diffusion method according to the guidelines of clinical laboratory standards institute (CLSI. Results The rates of resistance were high to clindamycin, tetracycline, and erythromycin (97.2%, 89%, and 74.5%, respectively; moderate to ciprofloxacilin and levofloxacilin (40.6% and 36.4%, respectively; and low to ampicillin and nitrofurantoin (13.8% and 3.5%, respectively. All isolates were linezolid sensitive. Vancomycin-resistant enterococci (VRE accounted for 9.6% of the isolates. Conclusions VRE and a high rate of resistance to some of antimicrobial agents were found among the enterococci isolated from patients in Tehran. These findings highlight the importance of regular supervision of antimicrobial susceptibilities.
Edmir Geraldo Fraga
Full Text Available Abstract Clostridium difficile is a leading cause of diarrhea in hospitalized patients worldwide. While metronidazole and vancomycin are the most prescribed antibiotics for the treatment of this infection, teicoplanin, tigecycline and nitazoxanide are alternatives drugs. Knowledge on the antibiotic susceptibility profiles is a basic step to differentiate recurrence from treatment failure due to antimicrobial resistance. Because C. difficile antimicrobial susceptibility is largely unknown in Brazil, we aimed to determine the profile of C. difficile strains cultivated from stool samples of inpatients with diarrhea and a positive toxin A/B test using both agar dilution and disk diffusion methods. All 50 strains tested were sensitive to metronidazole according to CLSI and EUCAST breakpoints with an MIC90 value of 2 μg/mL. Nitazoxanide and tigecycline were highly active in vitro against these strains with an MIC90 value of 0.125 μg/mL for both antimicrobials. The MIC90 were 4 μg/mL and 2 μg/mL for vancomycin and teicoplanin, respectively. A resistance rate of 8% was observed for moxifloxacin. Disk diffusion can be used as an alternative to screen for moxifloxacin resistance, nitazoxanide, tigecycline and metronidazole susceptibility, but it cannot be used for testing glycopeptides. Our results suggest that C. difficile strains from São Paulo city, Brazil, are susceptible to metronidazole and have low MIC90 values for most of the current therapeutic options available in Brazil.
Fraga, Edmir Geraldo; Nicodemo, Antonio Carlos; Sampaio, Jorge Luiz Mello
Clostridium difficile is a leading cause of diarrhea in hospitalized patients worldwide. While metronidazole and vancomycin are the most prescribed antibiotics for the treatment of this infection, teicoplanin, tigecycline and nitazoxanide are alternatives drugs. Knowledge on the antibiotic susceptibility profiles is a basic step to differentiate recurrence from treatment failure due to antimicrobial resistance. Because C. difficile antimicrobial susceptibility is largely unknown in Brazil, we aimed to determine the profile of C. difficile strains cultivated from stool samples of inpatients with diarrhea and a positive toxin A/B test using both agar dilution and disk diffusion methods. All 50 strains tested were sensitive to metronidazole according to CLSI and EUCAST breakpoints with an MIC90 value of 2μg/mL. Nitazoxanide and tigecycline were highly active in vitro against these strains with an MIC90 value of 0.125μg/mL for both antimicrobials. The MIC90 were 4μg/mL and 2μg/mL for vancomycin and teicoplanin, respectively. A resistance rate of 8% was observed for moxifloxacin. Disk diffusion can be used as an alternative to screen for moxifloxacin resistance, nitazoxanide, tigecycline and metronidazole susceptibility, but it cannot be used for testing glycopeptides. Our results suggest that C. difficile strains from São Paulo city, Brazil, are susceptible to metronidazole and have low MIC90 values for most of the current therapeutic options available in Brazil.
Full Text Available When it is necessary to determine the susceptibility of Neisseria meningitidis (Nm strains to antimicrobial drugs, it is important to consider that it should be analyzed in a double context. One of them related to the use of drugs in a specific medical treatment; and the other; to chemoprophylatic drugs, both with the same purpose: the accurate selection of the “in vivo” antimicrobial agent. This requires the study of the sensitivity and resistance of strains isolated in both carriers and patients. With the aim of further studying the behavior of the strains that currently circulate in Cuba, an antimicrobial drug susceptibility study was conducted in 90 strains isolated from carriers during the first half of 1998. The agar dilution method was used to determine the minimum inhibitory concentrations (MICs to: penicillin, ampicillin, rifampin, sulfadiazine, chloramphenicol, ciprofloxacin, ceftriaxone, cefotaxime. The study of the three latter drugs was done for the first time in our country. The search for β- lactamase-producer strains was also performed. There was a predominance of penicillin sensitive strains (82,2% with an intermediate sensitivity to ampicillin (57,8%, while 70% of the strains were sensitive to sulfadiazine. Regarding the rest of the antimicrobial drugs, 100% of the strains were sensitive. The paper shows the MICs for each drug as well as the phenotypic characteristics of the strains with the penicillin and sulfadiazine sensitivity and resistance patterns. No β-lactamase-producer strains were found.
Although often dismissed as contaminants when isolated from blood cultures, Bacillus spp. are increasingly recognized as capable of causing serious systemic infections. As part of a clinical-microbiological study, 89 strains of Bacillus spp. isolated from clinical blood cultures between 1981 and 1985 had their species determined and were tested for antimicrobial agent susceptibility to 18 antibiotics. Species of isolates were determined by the API 50CH and API 20E systems. Bacillus cereus (54...
Carlos Augusto de Oliveira Júnior
Full Text Available Clostridium perfringens is a microorganism commonly found in the microbiota of humans and animals and a potential cause of enteric, muscle or nervous diseases. The treatment of these diseases is based on antimicrobial therapy and it is extremely important to know the antimicrobial susceptibility profile of the strains present in the region. The aim of this study was to evaluate the antimicrobial susceptibility of C. perfringens isolated from domestic and wild animals in Brazil against seven different antimicrobials. Forty-one strains from the stool samples of cattle (n = 12, buffalo (n = 2, goat (n = 3, dogs (n = 12 and wild carnivores (n = 12 were examined. The minimum inhibitory concentration was determined by the agar dilution method using Brucella agar supplemented with 5% of sheep blood, 0.1% of vitamin K, 0.1% of hemin and concentrations ranging from 0,25 to 256,0 mg L-1 of the following antibiotics: erythromycin, florfenicol, metronidazole, oxytetracycline, penicillin, tylosin, and vancomycin. All C. perfringens strains were susceptible to florfenicol, metronidazole, penicillin and vancomycin. Two strains (4.9% were resistant to erythromycin and tylosin, while five (12.2% were resistant to oxytetracycline, one of which (2.4% from an ocelot.
Båverud, V; Gunnarsson, A; Karlsson, M; Franklin, A
The antimicrobial susceptibility of 50 Clostridium difficile isolates, 36 of them from horse feces and 14 from environmental sites, was determined by broth microdilution. The antimicrobial agents tested were avilamycin, cephalothin, chloramphenicol, clindamycin, erythromycin, gentamicin, neomycin, oxacillin, oxytetracycline, penicillin, spiramycin, streptomycin, trimethoprim/sulfamethoxazole, vancomycin, and virginiamycin. All isolates were susceptible to vancomycin (MIC MICs of erythromycin, oxytetracycline, spiramycin, and virginiamycin showed a bimodal distribution. Compared with the majority of isolates, the MICs of erythromycin (MIC > 16 microg/ml), oxytetracycline (MIC >/=32 microg/ml), spiramycin (MIC > 16 microg/ml), and virginiamycin (MIC 8-16 microg/ml) were higher for 18 isolates. Those were mainly isolated from horses at animal hospitals and further from environmental sites at a stud farm. In contrast, all isolates, except one, from healthy foals had low MICs of erythromycin, spiramycin, virginiamycin, and oxytetracycline. The isolates from soil in public parks had also low MICs of these antimicrobial agents. Broth microdilution appeared both reliable and reproducible for susceptibility testing of C. difficile. The method was also readily performed and the MIC endpoints were easily read.
Kreizinger, Zsuzsa; Sulyok, Kinga Mária; Makrai, László; Rónai, Zsuzsanna; Fodor, László; Jánosi, Szilárd; Gyuranecz, Miklós
The susceptibility of 29 Bacillus anthracis strains, collected in Hungary between 1933 and 2014, was tested to 10 antibiotics with commercially available minimum inhibitory concentration (MIC) test strips. All strains were susceptible to amoxicillin, ciprofloxacin, clindamycin, doxycycline, gentamicin, penicillin, rifampicin, and vancomycin. Intermediate susceptibility to erythromycin and cefotaxime was detected in 17.2% (5/29) and 58.6% (17/29) of the strains, respectively. Correlations were not observed between the isolation date, location, host species, genotype, and antibiotic susceptibility profile of strains.
Weber, D J; Saviteer, S M; Rutala, W A; Thomann, C A
Although often dismissed as contaminants when isolated from blood cultures, Bacillus spp. are increasingly recognized as capable of causing serious systemic infections. As part of a clinical-microbiological study, 89 strains of Bacillus spp. isolated from clinical blood cultures between 1981 and 1985 had their species determined and were tested for antimicrobial agent susceptibility to 18 antibiotics. Species of isolates were determined by the API 50CH and API 20E systems. Bacillus cereus (54 strains) was the most common species isolated, followed by B. megaterium (13 strains), B. polymyxa (5 strains), B. pumilus (4 strains), B. subtilis (4 strains), B. circulans (3 strains), B. amyloliquefaciens (2 strains), B. licheniformis (1 strain), and Bacillus spp. (3 strains). Microdilution MIC susceptibility tests revealed all B. cereus strains to be susceptible to imipenem, vancomycin, chloramphenicol, gentamicin, and ciprofloxacin. Non-B. cereus strains were most susceptible to imipenem, vancomycin, LY146032, and ciprofloxacin. Disk susceptibility testing suggested that B. cereus was rarely susceptible to penicillins, semisynthetic penicillins, or cephalosporins with the exception of mezlocillin. In contrast, many non-B. cereus strains were susceptible to penicillins, semisynthetic penicillins, and cephalosporins, but marked variability was noted among species. PMID:3395100
Goudarzi, Mehdi; Heidary, Mohsen; Azad, Mehdi; Fazeli, Maryam; Goudarzi, Hossein
Aim: The purpose of this study was to determine the antibiotic susceptibility pattern and distribution of integron in H. pylori isolates collected from patients referred to private health care centers in Tehran, Iran. Background: Antibiotic resistance is the main reason for failure of Helicobacter pylori therapy. Integrons as genetic reservoirs play main roles in the dissemination of antimicrobial resistance gene. Methods: During a 12-month cross-sectional study period, 65 H. pylori isolates were recovered from 124 biopsy specimens. Isolates were subjected to susceptibility testing using by Epsilometer test according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guideline. PCR was used to detect different types of integrons. Results: Antimicrobial susceptibility testing revealed that 73.8% of isolates were resistant to metronidazole, 43.1% to clarithromycin, 29.2% to tetracycline, 27.7% to amoxicillin, 23.1% to rifampicin and 13.4% to levofloxacin. Frequency of multidrug resistance among H. pylori isolates was 26.1%. The most predominant resistance profiles among our isolates were included resistance to clarithromycin and metronidazole (20%). Class 1 and 2 integrons were detected in 8 (12.3%) and 15 (23.1%) of the isolates, respectively. Conclusions: The high prevalence of multidrug resistance and frequency of class 2 integron in this survey can be a warning for clinicians. Continuous surveillance is necessary for the development of new treatment protocols to prevent the treatment failures and also further spread of resistant isolates. PMID:28224028
Veloo, A. C. M.; Seme, K.; Raangs, E.; Rurenga, P.; Singadji, Z.; Wekema-Mulder, G.; van Winkelhoff, A. J.
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
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
Baron, Sandrine; Lesne, Jean; Jouy, Eric; Larvor, Emeline; Kempf, Isabelle; Boncy, Jacques; Rebaudet, Stanilas; Piarroux, Renaud
We investigated the antimicrobial susceptibility of 50 environmental isolates of Vibrio cholerae non-O1/non-O139 collected in surface waters in Haiti in July 2012, during an active cholera outbreak. A panel of 16 antibiotics was tested on the isolates using the disk diffusion method and PCR detection of seven resistance-associated genes (strA/B, sul1/2, ermA/B, and mefA). All isolates were susceptible to amoxicillin-clavulanic acid, cefotaxime, imipenem, ciprofloxacin, norfloxacin, amikacin, and gentamicin. Nearly a quarter (22.0%) of the isolates were susceptible to all 16 antimicrobials tested and only 8.0% of the isolates (n = 4) were multidrug-resistant. The highest proportions of resistant isolates were observed for sulfonamide (70.0%), amoxicillin (12.0%), and trimethoprim-sulfamethoxazole (10.0%). One strain was resistant to erythromycin and one to doxycycline, two antibiotics used to treat cholera in Haiti. Among the 50 isolates, 78% possessed at least two resistance-associated genes, and the genes sul1, ermA, and strB were detected in all four multidrug-resistant isolates. Our results clearly indicate that the autochthonous population of V. cholerae non-O1/non-O139 found in surface waters in Haiti shows antimicrobial patterns different from that of the outbreak strain. The presence in the Haitian aquatic environment of V. cholerae non-O1/non-O139 with reduced susceptibility or resistance to antibiotics used in human medicine may constitute a mild public health threat. PMID:27818656
Lilenbaum, W; Veras, M; Blum, E; Souza, G N
Samples were obtained from 65 unmedicated adult dogs, processed for isolation of Staphylococcus species and tested for susceptibility to penicillin G, gentamicin, oxacillin, tetracycline, trimethoprim-sulphamethoxazole, streptomycin, ampicillin and rifampin. Forty-four isolates were obtained, which represents 67.7% of samples. Coagulase-negative species were most commonly found, and the most frequently isolated staphylococcus species were Staph. epidermidis and Staph. aureus. Other species, such as Staph. simulans, Staph. haemolyticus, Staph. saprophyticus and Staph. intermedius were also isolated. Resistance to antibiotics was frequently observed, with 90.9% of the isolates showing resistance to at least one drug. The most active antimicrobial agents against staphylococci isolated from otitis externa of dogs were rifampin and oxacillin. Multidrug resistance was a common finding, and one strain of Staph. haemolyticus species, was resistant to all tested antimicrobial agents. Resistance to three or more different drugs was a common finding, observed in 16 strains (36.4%) of both coagulase-positive and coagulase-negative staphylococci. This study highlights the emergence of cases of otitis externa determined by coagulase-negative staphylococcus strains and once more emphasizes the need for bacterial culture with species identification and susceptibility testing of swab specimens from the ear canal in order to choose appropriate antimicrobial agents.
Kalender, H.; Sen, S.; Hasman, Henrik
Thirty-eight Salmonella Enteritidis isolates from chickens and chicken meat in Turkey were examined for antimicrobial susceptibility, XbaI pulsed-field gel electrophoresis (PFGE) patterns, phage types, plasmid profiles, and resistance genes. Seven different PFGE patterns were observed...
To determine if Campylobacter isolation method influenced antimicrobial susceptibility results, the minimum inhibitory concentrations (MIC) of nine antimicrobials were compared for 291 pairs of Campylobacter isolates recovered from chicken carcass rinse samples using direct plating and an enrichment...
Heuer, Ole Eske; Pedersen, Karl; Andersen, J.S.;
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...
Dargatz, David A; Marshall, Katherine L; Fedorka-Cray, Paula J; Erdman, Matthew M; Kopral, Christine A
Salmonella is a major cause of foodborne illness and can cause clinical disease in animals. Understanding the on-farm ecology of Salmonella will be helpful in decreasing the risk of foodborne transmission. An objective of this study was to determine the prevalence of Salmonella among fecal samples collected on sheep operations in the United States. Another objective was to compare the use of composite fecal samples with fecal samples collected from individual sheep as a tool for screening sheep flocks for Salmonella. Sheep fecal samples (individual and composite) were collected on operations in 22 states. Salmonella isolates were characterized with regard to species, serotype, and antimicrobial susceptibility profile. Most operations (72.1%) had at least one positive sample and overall 26.9% of samples were positive. The percentage of positive samples varied by animal age class. Composite and individual samples gave similar results. The majority of the isolates (94%) were Salmonella enterica subspecies diarizonae serotype 61:-:1,5,7. Nearly all of the isolates (91.2%) tested for antimicrobial susceptibility were susceptible to all antimicrobials in the panel. The findings suggest that salmonellae typically associated with foodborne disease transmission are infrequently found on sheep operations in the United States.
Vidovic, Sinisa; Tsoi, Sarah; Medihala, Prabhakara; Liu, Juxin; Wylie, John L; Levett, Paul N; Korber, Darren R
A population-based study combining (i) antimicrobial, (ii) genetic, and (iii) virulence analyses with molecular evolutionary analyses revealed segregative characteristics distinguishing human clinical and bovine Escherichia coli O157 strains from western Canada. Human (n = 50) and bovine (n = 50) strains of E. coli O157 were collected from Saskatchewan and Manitoba in 2006 and were analyzed by using the six-marker lineage-specific polymorphism assay (LSPA6), antimicrobial susceptibility analysis, the colicin assay, plasmid and virulence profiling including the eae, ehxA, espA, iha, stx1, stx2, stx2c, stx2d, stx2d-activatable, stx2e, and stx2f virulence-associated genes, and structure analyses. Multivariate logistic regression and Fisher's exact test strongly suggested that antimicrobial susceptibility was the most distinctive characteristic (P = 0.00487) associated with human strains. Among all genetic, virulence, and antimicrobial determinants, resistance to tetracycline (P coli O157 strains. Among 11 virulence-associated genes, stx2c showed the strongest association with E. coli O157 strains of bovine origin. LSPA6 genotyping showed the dominance of the lineage I genotype among clinical (90%) and bovine (70%) strains, indicating the importance of lineage I in O157 epidemiology and ecology. Population structure analysis revealed that the more-diverse bovine strains came from a unique group of strains characterized by a high degree of antimicrobial resistance and high frequencies of lineage II genotypes and stx2c variants. These findings imply that antimicrobial resistance generated among bovine strains of E. coli O157 has a large impact on the population of this human pathogen.
Cristhiane Moura Falavina dos Reis
Full Text Available INTRODUCTION: Listeria monocytogenes is the causative agent of listeriosis, a foodborne illness that affects mainly pregnant women, the elderly and immunocompromised patients. The primary treatment is a combination of ampicillin with an aminoglycoside, in addition to a second-choice drug represented by chloramphenicol, erythromycin, tetracycline and rifampicin. The aim of this study was to analyze the antimicrobial susceptibility profile of strains isolated from human sources in the last four decades. METHODS: Sixty-eight strains were selected from the culture collection of the Laboratory of Bacterial Zoonoses/LABZOO/FIOCRUZ isolated in different regions of Brazil from 1970 to 2008 and primarily isolated from cerebrospinal fluid and blood culture. Susceptibility tests to antimicrobials drugs were evaluated using the criteria established by Soussy using the Kirby-Bauer method and E-Test strips were used to determine the minimum inhibitory concentration (MIC. RESULTS: Among the strains tested, serovar L4b (60.3% was the most prevalent, followed by serovar 1/2a (20.6%, 1/2b (13.2% and the more uncommon serovars 1/2c, 3b and 4ab (5.9%. All strains were susceptible to ampicillin, cephalothin, erythromycin, gentamicin, teicoplanin and vancomycin. Only one strain (1.5% showed resistance to rifampin, and two (3% were resistant to trimethoprim-sulfamethoxazole. MICs with values up to 2μg/ml reinforce the need for microbiological surveillance. CONCLUSIONS: The study demonstrated low prevalence of strains resistant to the antimicrobial drugs indicated in the treatment of human listeriosis. Monitoring antimicrobial resistance profile is still very important to determine adequate treatment, especially in immunocompromised patients.
Full Text Available Helicobacter pylori colonizes more than 50% of the world population thus, it is considered an important cause of gastric cancer. The aim of this study was to determine the isolation frequency of H. pylori in Southern Chile from patients with symptomatology compatible with gastritis or gastric ulcer and to correlate these findings with demographic parameters of infected patients and the susceptibility profiles of the isolated strains to the antimicrobial drugs used in the eradication treatments. A total of 240 patients were enrolled in the study. Each gastric biopsy was homogenized and seeded onto blood agar plates containing a selective antibiotics mixture (DENT supplement. Plates were incubated at 37° C in a microaerophilic environment for five days. The susceptibility profiles to amoxicillin, ciprofloxacin, clarithromycin, tetracycline and metronidazole were determined using the E-test method. H. pylori was isolated from 99 patients (41.3% with slightly higher frequency in female (42% positive cultures than male (40.2% positive cultures. With regard to age and educational level, the highest isolation frequencies were obtained in patients between 21-30 (55% and 41-50 (52.6% years old, and patients with secondary (43.9% and university (46.2% educational levels. Nineteen (21.6% strains showed resistance to at least one antimicrobial drug. Tetracycline was the most active antimicrobial in vitro, whereas metronidazole was the less active. One strain (5.3% showed resistance to amoxicillin, clarithomycin and metronidazole, simultaneously.
Aarestrup, Frank Møller; Knöchel, Susanne; Hasman, Henrik
for susceptibility to ceftiofur, chloramphenicol, ciprofloxacin, erythromycin, florfenicol, penicillin, spectinomycin, streptomycin, tetracycline, tiamulin, trimethoprim, and co-trimoxazole, and the disinfectants benzalkonium chloride and triclosan, by determination of minimum inhibitory concentrations (MICs). All...... isolates were resistant to ceftiofur, but susceptible to the other antibiotics. A single isolate had a MIC of 4 mg/L for ciprofloxacin. For tiamulin. the MIC values were around the breakpoint used. Most isolates had MICs for triclosan at 16 mg/L. The MICs for benzalkonium chloride formed a bimodal...... distribution, with 105 isolates having a MIC of 4 mg/L and 9 isolates MICs of 16 and 32 mg/L. This study showed that Danish isolates of L. monocytogenes have not developed or acquired resistance to antimicrobial agents used for treatment or disinfection, except for benzalkonium chloride. The MICs for triclosan...
Horn, Nicole Nari; Kresken, Michael; Körber-Irrgang, Barbara; Göttig, Stephan; Wichelhaus, Cornelia; Wichelhaus, Thomas A
Antimicrobial drug resistance in Neisseria gonorrhoeae has become an increasing public health problem. Hence, surveillance of resistance development is of crucial importance to implement adequate treatment guidelines. Data on the spread of antibiotic resistance among gonococcal isolates in Germany, however, is scarce. In a resistance surveillance study conducted by the Paul Ehrlich Society for Chemotherapy between October 2010 and December 2011, 23 laboratories all over Germany were requested to send N. gonorrhoeae isolates to the study laboratory in Frankfurt am Main. Species verification was performed biochemically using ApiNH and with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing was performed using the Etest method. For molecular epidemiological analysis, N. gonorrhoeae strains were genotyped by means of N. gonorrhoeae multi-antigen sequence typing. A total of 213 consecutive gonococcal isolates were analyzed in this nationwide study. Applying EUCAST breakpoints, high resistance rates were found for ciprofloxacin (74%) and tetracycline (41%). Penicillin non-susceptibility was detected in 80% of isolates. The rate of azithromycin resistance was 6%, while all strains were susceptible to spectinomycin, cefixime, and ceftriaxone. Molecular typing of gonococcal isolates revealed a great heterogeneity of 99 different sequence types (ST), but ST1407 predominated (n=39). This is the first comprehensive German multi-centre surveillance study on antibiotic susceptibility and molecular epidemiology of N. gonorrhoeae with implications for antibiotic choice for treatment of gonorrhoea. The World Health Organization supports the concept that an efficacious treatment of gonorrhoea results in at least 95% of infections being cured. Accordingly, as spectinomycin is not available on the German market, only the third generation cephalosporins cefixime and ceftriaxone are regarded as valuable drugs
Agnoletti, Fabrizio; Ferro, Tiziana; Guolo, Angela; Marcon, Barbara; Cocchi, Monia; Drigo, Ilenia; Mazzolini, Elena; Bano, Luca
Rabbit meat breeding may be heavily affected by enterotoxaemia due to Clostridium spiroforme. Data on its antimicrobial susceptibility are insufficient, presumably because of difficulties in cultivating and identifying the pathogen. Our aim is therefore to provide this information to veterinary practitioners by focusing on a panel of therapeutics used in intensive rabbit units. Lincomycin was also checked in order to investigate the origin of resistance to macrolides. Minimal inhibitory concentrations (MICs) were determined with the agar dilution method according to the CLSI M11-A7 protocol (2007). MIC(50) and MIC(90) were, respectively, 64 and 64microg/ml for tiamulin, 32 and 32microg/ml for norfloxacin, 0.063 and 0.125microg/ml for amoxicillin, and 8 and 16microg/ml for doxycycline. MIC(50) and MIC(90) were 256microg/ml for sulphadimethoxine, spiramycin and lincomycin. Our results have shown that intrinsic or acquired antimicrobial resistances are diffuse in the C. spiroforme population and suggest focusing on prevention rather than on treatment of clostridial overgrowth, by reducing risk factors and using antimicrobials prudently.
Schoster, Angelika; Staempfli, H. R.; Arroyo, L. G.;
were to investigate and molecularly characterize isolates of Clostridium difficile, Clostridium perfringens and Salmonella, collected sequentially over a one year period, and to determine the antibiotic susceptibility profile for E. coli. Fecal samples were collected monthly from 25 adult horses...... for one year. Selective cultures were performed for all above bacteria. C. difficile isolates were characterized via PCR toxin gene profiling and ribotyping. Broth microdilution was performed to assess antimicrobial susceptibility profiles of E. coli. Toxigenic Clostridium difficile was isolated from 15....... Resistance to =1 and = 3 antimicrobials was present in 31/232 (13.4%) and 6/232 (2.6%) respectively. Only two horses shed the same strain of toxigenic C. difficile for more than one month, indicating that shedding is transient. The high number of ribotype 078 is consistent with recent emergence...
Macià, M D; Rojo-Molinero, E; Oliver, A
Biofilms are organized bacterial communities embedded in an extracellular polymeric matrix attached to living or abiotic surfaces. The development of biofilms is currently recognized as one of the most relevant drivers of persistent infections. Among them, chronic respiratory infection by Pseudomonas aeruginosa in cystic fibrosis patients is probably the most intensively studied. The lack of correlation between conventional susceptibility test results and therapeutic success in chronic infections is probably a consequence of the use of planktonically growing instead of biofilm-growing bacteria. Therefore, several in vitro models to evaluate antimicrobial activity on biofilms have been implemented over the last decade. Microtitre plate-based assays, the Calgary device, substratum suspending reactors and the flow cell system are some of the most used in vitro biofilm models for susceptibility studies. Likewise, new pharmacodynamic parameters, including minimal biofilm inhibitory concentration, minimal biofilm-eradication concentration, biofilm bactericidal concentration, and biofilm-prevention concentration, have been defined in recent years to quantify antibiotic activity in biofilms. Using these parameters, several studies have shown very significant quantitative and qualitative differences for the effects of most antibiotics when acting on planktonic or biofilm bacteria. Nevertheless, standardization of the procedures, parameters and breakpoints, by official agencies, is needed before they are implemented in clinical microbiology laboratories for routine susceptibility testing. Research efforts should also be directed to obtaining a deeper understanding of biofilm resistance mechanisms, the evaluation of optimal pharmacokinetic/pharmacodynamic models for biofilm growth, and correlation with clinical outcome.
Due to the great variability in antimicrobial resistance patterns, local reports of cumulative antimicrobial susceptibility data are necessary in every health center. The purpose is to guide clinical decisions and the early detection of patterns that allow preventive measures to avoid dissemination of resistant strains. The main objective of this guide is to provide recommendations for the analysis of antimicrobial susceptibility data and elaboration of a local report. Recommendations provided in this guide are based on the Clinical and Laboratory Standards Institute (CLSI) document "Analysis and Presentation of Cumulative Antimicrobial Susceptibility Test Data" (3). Key aspects related to information gathering and data processing, analysis and presentation are described.
Gradin, J L; Schmitz, J A
The susceptibility of 18 strains of Bacteroides nodosus to 21 antimicrobial agents was tested in vitro. Penicillin was the most effective antibiotic tested. Other antibiotics tested, in order of relative efficacy, were cefamandole, clindamycin, tetracycline, chloramphenicol, erythromycin, sodium cefoxitin, tylosin tartrate, nitrofurazone, tinidazole, and dihydrostreptomycin sulfate. Tests of solutions of 4 antibiotics in 70% ethanol indicated that ethanol served primarily as a diluent and did not contribute substantially to the curative effect of such topical medications on foot rot lesions in sheep. Of the chemicals commonly used in foot baths for treatment of ovine foot rot, copper sulfate was most effective, followed by zinc sulfate, then formalin. Several commercial disinfectants and iodine were quite effective against B nodosus, whereas 5.25% sodium hypochlorite and 70% ethanol alone were relatively ineffective.
Full Text Available Urinary tract infections (UTIs are among the commonest types of bacterial infections. The antibiotic treatment for UTIs is associated with important medical and economic implications. Many different microorganisms can cause UTIs though the most common pathogens are E. coli and members of family Enterobacteriaceae. The knowledge of etiology and antibiotic resistance pattern of the organisms causing urinary tract infection is essential. The present study was undertaken to evaluate trends of antibiotic susceptibility of commonly isolated uropathogens using newer antimicrobial agents, prulifloxacin, fosfomycin (FOM and doripenem. We conclude that maintaining a record of culture results and the antibiogram may help clinicians to determine the empirical and/or specific treatment based on the antibiogram of the isolate for better therapeutic outcome.
Glauber P Arêas
Full Text Available Streptococcus pyogenes is responsible for a variety of infectious diseases and immunological complications. In this study, 91 isolates of S. pyogenes recovered from oropharynx secretions were submitted to antimicrobial susceptibility testing, emm typing and pulsed-field gel electrophoresis (PFGE analysis. All isolates were susceptible to ceftriaxone, levofloxacin, penicillin G and vancomycin. Resistance to erythromycin and clindamycin was 15.4%, which is higher than previous reports from this area, while 20.9% of the isolates were not susceptible to tetracycline. The macrolide resistance phenotypes were cMLSB (10 and iMLSB (4. The ermB gene was predominant, followed by the ermA gene. Thirty-two emm types and subtypes were found, but five (emm1, emm4, emm12, emm22, emm81 were detected in 48% of the isolates. Three new emm subtypes were identified (emm1.74, emm58.14, emm76.7. There was a strong association between emm type and PFGE clustering. A variety of PFGE profiles as well as emm types were found among tetracycline and erythromycin-resistant isolates, demonstrating that antimicrobial resistant strains do not result from the expansion of one or a few clones. This study provides epidemiological data that contribute to the development of suitable strategies for the prevention and treatment of such infections in a poorly studied area.
Liu, Tingting; Lu, Yi; Gau, Vincent; Liao, Joseph C; Wong, Pak Kin
Rapid pathogen detection and antimicrobial susceptibility testing (AST) are required in diagnosis of acute bacterial infections to determine the appropriate antibiotic treatment. Molecular approaches for AST are often based on the detection of known antibiotic resistance genes. Phenotypic culture analysis requires several days from sample collection to result reporting. Toward rapid diagnosis of bacterial infection in non-traditional healthcare settings, we have developed a rapid AST approach that combines phenotypic culture of bacterial pathogens in physiological samples and electrochemical sensing of bacterial 16S rRNA. The assay determines the susceptibility of pathogens by detecting bacterial growth under various antibiotic conditions. AC electrokinetic fluid motion and Joule heating induced temperature elevation are optimized to enhance the sensor signal and minimize the matrix effect, which improve the overall sensitivity of the assay. The electrokinetics enhanced biosensor directly detects the bacterial pathogens in blood culture without prior purification. Rapid determination of the antibiotic resistance profile of Escherichia coli clinical isolates is demonstrated.
Horii, Toshinobu; Notake, Shigeyuki; Tamai, Kiyoko; Yanagisawa, Hideji
We characterized the profiles of virulence genes and antimicrobial susceptibility of Bacillus cereus isolates from blood cultures as well as the risk factors for blood stream infections (BSIs). The diversity of virulence gene patterns was found to be wide among 15 B. cereus isolates from BSIs and also among 11 isolates from contaminated blood cultures. The MicroScan broth microdilution method yielded results corresponding with those of the agar dilution (reference) method for levofloxacin, linezolid, and vancomycin, while the Etest results were consistent with the reference results for clindamycin, gentamicin, imipenem, levofloxacin, and linezolid. Compared with the reference values, however, some isolates showed marked differences of the minimum inhibitory concentrations (MICs) for ampicillin and clindamycin when determined using the MicroScan method, or the MICs for ampicillin, meropenem, and vancomycin when determined using the Etest method. Significantly more patients were treated with antimicrobials for more than 3 days during the 3-month period before isolation in the BSI group. Prior antimicrobial therapy may be a risk factor for BSIs due to B. cereus.
Full Text Available Aim: Hospital infections are important uptodate health problems because of high mortality and increased cost. The increment in antimicrobial resistance is progressing though new antimicrobial agents are arising. This leads to an increase in hospital infections and difficulty in treatment. In our study we aimed to evaluate the antimicrobial susceptibility of the strains isolated at Anesthesiology Intensive Care Unit. Material and Method: The antimicrobial susceptibility of the strains isolated at Anesthesiology Intensive Care Unit between April 1st 2012- October 25th 2012 were included. The identification and the antimicrobial susceptibility were studied by automatized Vitek version 2.0 (Biomerieux, France. Results: A total of 155 strains isolated from wound, blood, tracheal secretion, sputum and urine samples were included. They are consisted of 40 A. baumannii, 24 E.coli, 25 P. aeruginosa, 20 K.pneumoniae, 12 Methicilin Resistant Coagulase Negative Staphylococci (MRCoNS, nine Methiciline Susceptible S.aureus (MSSA, eight C.albicans, four Methicilin Resistant S.aureus (MRSA, one C.famata, one C.tropicalis, three E.faecalis, two E.faecium, three S.marsecens, two P. mirabilis and one H.influenzae. Clinical samples were 81 tracheal secretions, 25 wound specimen, 23 blood culture, 18 urine, seven sputum, and one BAL. All the Gram positive strains were susceptible to glycopeptides. Enterobacteriaceae members were susceptible to imipenem and meropenem. Discussion: Antimicrobial resistance is an important issue worldwide. Multidiciplinary approach is needed as in ICUs where the complicated patients are followed. Monitoring antibiotic resistance profile contributes to treatment and decreasing resistance rates. The resistance profile will guide the antibiotic use policy. Increment in number of isolates in future will help to obtain the antimicrobial resistance profile.
Dorbecker, C.; Sander, A.; Oberle, K.; Schulin-Casonato, T.
OBJECTIVES: In vitro susceptibility testing of 31 Bartonella spp. strains including 21 Bartonella henselae isolates was performed for 17 antimicrobial agents (telithromycin, four macrolides, five fluoroquinolones, five aminoglycosides, doxycycline and rifampicin). METHODS: MICs were determined by ag
Esmaeili Dooki, Mohammad Reza; Rajabnia, Ramazan; Barari Sawadkohi, Rahim; Mosaiebnia Gatabi, Zahra; Poornasrollah, Mohammad; Mirzapour, Mohaddeseh
Background: Infectious diarrhea is one of common cause of children diarrhea causing mortality and morbidity worldwide. This study was performed to identify the common bacteria and their antimicrobial susceptibility in children with diarrhea.
Ikeda, Mahoko; Yagihara,Yuka; Tatsuno, Keita; Okazaki, Mitsuhiro; Okugawa, Shu; Moriya, Kyoji
Background Bacillus cereus is one of the pathogens causing nosocomial bloodstream infections (BSIs). However, few reports have documented the antimicrobial susceptibility and clinical characteristics of Bacillus cereus BSI and the importance of empirical therapy. The aim of this study was to investigate the clinical characteristics and antimicrobial susceptibility of B. cereus isolates from patients with BSI and to analyze the impact of appropriate empirical therapy on the outcome of patients...
Jacob, Megan E; Fox, James Trent; Reinstein, Shelby L; Nagaraja, T G
Organic and natural food production systems are increasing in popularity, at least partially because consumers perceive that these niche markets provide healthier and safer food products. One major difference between these niche markets and conventional production systems is the use of antimicrobials. Because antimicrobial agents exert selective pressures for antimicrobial resistance, relating antimicrobial susceptibility of foodborne bacteria to niche market production systems is of interest. Other differences between production systems might also influence the susceptibility of foodborne pathogens. The objective of this review is to compare the impact of food animal production systems on the antimicrobial susceptibility of common foodborne bacterial pathogens. Studies comparing the susceptibility of such pathogens were diverse in terms of geographic location, procedures, species of bacteria, and antimicrobials evaluated; thus, it was difficult to draw conclusions. The literature is highly variable in terms of production type and practices and susceptibility associations, although few studies have compared truly organic and conventional practices. When statistical associations were found between production type and minimum inhibitory concentrations or percentage of isolates resistant for a particular pathogen, the isolates from conventionally reared animals/products were more commonly resistant than the comparison group (organic, antibiotic free, etc.). Therefore, further studies are needed to better assess public health consequences of antimicrobial resistance and food animal production systems, specifically organic or natural versus conventional.
Zamankhan Malayeri, Hamed; Jamshidi, Shahram; Zahraei Salehi, Taghi
Bacterial agents are considered important pathogens causing external otitis in dogs. It is essential to carry out bacterial culture and antimicrobial susceptibility test in the case of otitis externa, particularly for chronic or recurring cases. Sterile swab samples were obtained from terminal part of vertical ear canals of 74 dogs with otitis externa for cytology, bacterial culture and antimicrobial susceptibility test. Cytologic smears were stained using Gram and Giemsa staining methods. Aerobic bacterial culture performed on blood agar and MacConkey agar. Among total number of 92 isolated bacteria, 68 were Staphylococcus intermedius. Other isolated bacteria included: Pseudomonas aeruginosa, Proteus mirabilis, Escherichia coli, Pasteurella canis, and six other species of coagulase-negative Staphylococcus. Antimicrobial susceptibility test were performed for all isolated bacteria using 14 antibiotics. Based on the results of this study, all isolated Staphylococcus spp. were sensitive to amikacin, enrofloxacin, and rifampin, and had low resistance to gentamicin, cephalothin and ceftriaxone. More than half of gram-positive isolates were resistant to penicillin and ampicillin. Generally, all isolated gram-negative bacteria, were sensitive to amikacin and enrofloxacin, and had low resistance to ceftriaxone and gentamicin. They were highly resistant to penicillin, eythromycin, and cephalothin. Regarding the results of this study, in cases of uncomplicated otitis externa, it is possible to select antimicrobial drugs merely based on cytology, but it is recommended to perform bacterial culture and antimicrobial susceptibility test. However, in complicated or refractory cases, antimicrobials should be selected based on bacterial culture and antimicrobial susceptibility test.
Maria Antonietta Distasi
Full Text Available Blood cultures have the drawback of requiring long time to be carried out. Our study was designed with the aim of early reports on both causing agents and preliminary antimicrobial susceptibility. We carried out a direct antimicrobial susceptibility on 79 positive blood cultures (42 for Gram-negative bacteria of which 21 MDRO; 22 for staphylococci of which 15 S. aureus; and 15 Enterococci/Streptococci employing E-test strips deposited on Müller-Hinton Agar for staphylococci and Gram-negative bacteria, and Müller-Hinton Agar + 5% of blood for enterococci/streptococci. MICs were compared to the antimicrobial susceptibility tests carried out using Vitek2. On the basis of the interpretative criteria (SIR, the comparison between the direct antimicrobial susceptibility and the routine antimicrobial susceptibility, showed a concordance from 92.6% up to 100% for Gram-negative bacteria; from 90.0% up to 100% for staphylococci; from 86.7% up to 100% for streptococci/enterococci, respectively. With regard to MICs comparison, good concordance was detected on the basis of ± 1 doubling dilution. Moreover, this work allowed, in the case of Gram-negative bacteria, either the early identification of multidrug-resistant organisms or providing the MIC evaluation in a broader interval than it would be possible by the reference antimicrobial susceptibility.
Alessandra Marques Cardoso
Full Text Available Testing of rapidly growing species of mycobacteria (RGM against antibacterial agents has been shown to have some clinical utility. This work establishes the MICs of seven antimicrobial agents following the guidelines set forth by the Clinical and Laboratory Standards Institute (CLSI against eighteen isolates of Mycobacterium massiliense recovered from wound samples of patients submitted to minimally invasive surgery such as arthroscopy and laparoscopy. The isolates showed susceptibility to amikacin (MIC90=4 μg/mL and clarithromycin (MIC9016 μg/mL, doxycycline (MIC90>32 μg/mL, sulfamethoxazole (MIC90>128 μg/mL, and tobramycin (MIC90=32 μg/mL, and intermediate profile to cefoxitin (MIC90=64 μg/mL. Therefore, we suggest that the antimicrobial susceptibilities of any clinically significant RGM isolate should be performed.
Full Text Available Antimicrobials are widely used, not only for treating human infections, but also for treatment of livestock and in fish farms. Human habitats in Southeastern Asian countries are located in close proximity to aquatic environments. As such, the human populations within these regions are at risk of exposure to antimicrobial resistant bacteria (ARB, and thereby disseminating antimicrobial resistance genes (ARGs. In this study, we collected water samples from 15 sites (5 sites in Chao Phraya River, 2 sites at the mouth of Chao Phraya River, 3 sites in Ta Chin River, and 5 sites at city canals and 12 sites (6 sites at city canals, 2 sites at chicken farms, 2 sites at pig farms, and 2 samples from sites at pig farms that were subsequently treated at a biogas plant in Thailand in 2013 and 2014, respectively. In total, 117 Aeromonas spp. were isolated from the water samples, and these organisms exhibited various antimicrobial susceptibility profiles. Moreover, there was a significant correlation between the environmental concentration of tetracyclines and the rates of tetracycline resistance in the isolated Aeromonas spp. Notably, however, the concentration and resistance rates of tetracycline in samples derived from pig farms were higher than those of samples harvested from other aquatic environments. These findings suggest that the high concentrations of antimicrobials observed in these aquatic environments likely select for ARGs. Furthermore, they indicate that Aeromonas spp. comprise an effective marker for monitoring antimicrobial resistance in aquatic environments.
Usui, Masaru; Tagaki, Chie; Fukuda, Akira; Okubo, Torahiko; Boonla, Chanchai; Suzuki, Satoru; Seki, Kanako; Takada, Hideshige; Tamura, Yutaka
Antimicrobials are widely used, not only for treating human infections, but also for treatment of livestock and in fish farms. Human habitats in Southeastern Asian countries are located in close proximity to aquatic environments. As such, the human populations within these regions are at risk of exposure to antimicrobial resistant bacteria, and thereby disseminating antimicrobial resistance genes (ARGs). In this study, we collected water samples from 15 sites (5 sites in Chao Phraya River, 2 sites at the mouth of Chao Phraya River, 3 sites in Ta Chin River, and 5 sites at city canals) and 12 sites (6 sites at city canals; 2 sites at chicken farms; 2 sites at pig farms; and 2 samples from sites at pig farms, which were subsequently treated at a biogas plant) in Thailand in 2013 and 2014, respectively. In total, 117 Aeromonas spp. were isolated from the water samples, and these organisms exhibited various antimicrobial susceptibility profiles. Notably, there was a significant correlation between the environmental concentration of tetracyclines and the rates of tetracycline resistance in the isolated Aeromonas spp.; however, both the concentration and rates of tetracycline resistance in samples derived from pig farms were higher than those of samples harvested from other aquatic environments. These findings suggest that the high concentrations of antimicrobials observed in these aquatic environments likely select for ARGs. Furthermore, they indicate that Aeromonas spp. comprise an effective marker for monitoring antimicrobial resistance in aquatic environments.
de la Fuente, A J Martín; Tucker, A W; Navas, J; Blanco, M; Morris, S J; Gutiérrez-Martín, C B
A total of 30 British and 30 Spanish Haemophilus parasuis isolates were tested for their susceptibility to 19 of the antimicrobials currently used in swine practice with a broth microdilution method in order to know the emergence of resistance against these compounds in this porcine pathogen. All the British isolates were susceptible to penicillin, ceftiofur, erythromycin, tilmicosin, enrofloxacin, and florfenicol, and most of them were susceptible to the remaining antimicrobials (the highest resistance rate found was of 20% to neomycin). In contrast, all the Spanish isolates were susceptible exclusively to florfenicol, and high proportions of resistance were encountered for penicillin, ampicillin, oxytetracycline, erythromycin, tilmicosin, tiamulin and trimethoprim+sulphamethoxazole; in addition, a bimodal or multimodal distribution, or tailing of Spanish isolates over the MIC range was observed for clindamycin, sulphonamides and tylosine tartrate, suggesting the development of acquired resistance. In addition, several multiresistance patterns were found among the Spanish isolates, 23.3% of them being resistant to at least eight antimicrobials, the same rate as that encountered for those being susceptible to all antimicrobials tested. This study showed that in general British H. parasuis isolates are susceptible to antimicrobial agents routinely used for treatment of porcine respiratory diseases; however, the Spanish isolates need a more continuous surveillance of their susceptibility patterns.
Andreea BODOCZI FLOREA
Full Text Available We studied the prevalence of antimicrobial resistance (AR and multiple antimicrobial resistances (MAR among the faecal bacteria found in the Arieş river (Romania affected by strong anthropogenic pressures. Isolation and identification of E. coli were done by using enrichment media, selective media, and biochemical tests. Antimicrobial susceptibility testing by the disk diffusion method was conducted for 12 antimicrobial agents: ciprofloxacin, gentamicin, streptomycin, ceftazidin, ofloxacin, sulfamethoxazole, ticarcycline, ampicillin, nalidixic acid, nitrofurantoin, erythromycin, and norfloxacin. The data of the antimicrobial susceptibility reviled that all the studied E. coli strains were resistant to most of the tested antibiotics. The analysis of antibiotic resistance frequencies has showed an incidence of 46.66% strains resistant to more than 4 different antibiotics. Moreover, a high incidence of multiple antibiotic resistances was detected in each of the studied samples.
Sifré, Elodie; Salha, Ben Amor; Ducournau, Astrid; Floch, Pauline; Chardon, Hubert; Mégraud, Francis; Lehours, Philippe
Antimicrobial susceptibility testing of Campylobacter isolates is of great importance for treatment options especially in systemic diseases. The European Committee for Antimicrobial Susceptibility Testing (EUCAST) recently proposed epidemiological cut-offs (ECOFFs) for a limited number of antimicrobial compounds and for Campylobacter jejuni and Campylobacter coli only. In the present study, the EUCAST method was used after minor modifications to define antimicrobial susceptibility patterns for, 1997 C. jejuni, 419 C. coli and 100 Campylobacter fetus strains received at the French National Reference Center for Campylobacters and Helicobacters. Our results show that the ECOFFs defined by EUCAST for tetracycline and ciprofloxacin can be used for C. jejuni and C. coli. The same ECOFF can be used for erythromycin for the three species. The C. jejuni and C. coli ECOFFs for ciprofloxacin however cannot be applied to C. fetus. We also provide data to categorise two 2 β-lactams of interest for systemic diseases, ampicillin and amoxicillin+clavulanate, for the three species.
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...
Full Text Available In this study, 24 standard nontuberculous mycobacteria (NTM species strains including 12 slowly growing mycobacteria strains and 12 rapidly growing mycobacteria strains were subjected to drug susceptibility testing using microplate Alamar Blue assay-based 7H9 broth. The most active antimicrobial agents against the 24 NTM strains were streptomycin, amikacin, the fluoroquinolones, and the tetracyclines. Mycobacterium chelonae, Mycobacterium abscessus, Mycobacterium bolletii, and Mycobacterium simiae are resistant to most antimicrobial agents. The susceptibility results of this study from 24 NTM standard strains can be referenced by clinicians before susceptibility testing for clinical isolates is performed or when conditions do not allow for susceptibility testing. The application of broth-based methods is recommended by the Clinical and Laboratory Standards Institute, and the documentation of the susceptibility patterns of standard strains of mycobacteria can improve the international standardization of susceptibility testing methods.
Beigverdi, Reza; Jabalameli, Fereshteh; Mirsalehian, Akbar; Hantoushzadeh, Sedigheh; Boroumandi, Shahram; Taherikalani, Morovat; Emaneini, Mohammad
Forty-one Streptococcus agalactiae isolates collected from pregnant women at 35-37 weeks of gestation were analysed for their capsular types, antimicrobial resistance determinants, distribution of virulence factors and genetic relatedness using PCR and multiplex PCR. Capsular type III was predominant (65.8%), followed by capsular type II (14.6%), Ib (7.3%), and V(4.9%). All isolates were susceptible to penicillin, vancomycin, linezolid and quinupristin-dalfopristin. Resistance to tetracycline, erythromycin and clindamycin were found in 97.6%, 24.4%, and 14.6% of isolates, respectively. The most common antimicrobial resistance gene was tetM found in 97.6% of the isolates followed by ermTR and ermB found in 12% and 7.3% of isolates, respectively. The most common virulence gene was hly (100%), followed by scpB (97.6%), bca (97.6%), rib (53.65%) and bac (4.9%). The insertion sequence IS1548 was found in 63.4% of isolates. By multi locus variable number of tandem repeat analysis (MLVA) typing, 30 different allelic profiles or MLVA types (MTs) were identified. The most frequent was the MT1 (5/41, 12.2%) and followed by MT2 (4/41, 9.75%). Our data revealed that population structure of these isolates is highly diverse and indicates different MLVA types.
Holt, H M; Danielsen, T K; Justesen, U S
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....
Mirajkar, Nandita S.; Davies, Peter R.
Outbreaks of swine dysentery, caused by Brachyspira hyodysenteriae and the recently discovered “Brachyspira hampsonii,” have reoccurred in North American swine herds since the late 2000s. Additionally, multiple Brachyspira species have been increasingly isolated by North American diagnostic laboratories. In Europe, the reliance on antimicrobial therapy for control of swine dysentery has been followed by reports of antimicrobial resistance over time. The objectives of our study were to determine the antimicrobial susceptibility trends of four Brachyspira species originating from U.S. swine herds and to investigate their associations with the bacterial species, genotypes, and epidemiological origins of the isolates. We evaluated the susceptibility of B. hyodysenteriae, B. hampsonii, Brachyspira pilosicoli, and Brachyspira murdochii to tiamulin, valnemulin, doxycycline, lincomycin, and tylosin by broth microdilution and that to carbadox by agar dilution. In general, Brachyspira species showed high susceptibility to tiamulin, valnemulin, and carbadox, heterogeneous susceptibility to doxycycline, and low susceptibility to lincomycin and tylosin. A trend of decreasing antimicrobial susceptibility by species was observed (B. hampsonii > B. hyodysenteriae > B. murdochii > B. pilosicoli). In general, Brachyspira isolates from the United States were more susceptible to these antimicrobials than were isolates from other countries. Decreased antimicrobial susceptibility was associated with the genotype, stage of production, and production system from which the isolate originated, which highlights the roles of biosecurity and husbandry in disease prevention and control. Finally, this study also highlights the urgent need for Clinical and Laboratory Standards Institute-approved clinical breakpoints for Brachyspira species, to facilitate informed therapeutic and control strategies. PMID:27252458
Ivancic, Vesna; Mastali, Mitra; Percy, Neil; Gornbein, Jeffrey; Babbitt, Jane T; Li, Yang; Landaw, Elliot M; Bruckner, David A; Churchill, Bernard M; Haake, David A
We describe the first direct testing of the antimicrobial susceptibilities of bacterial pathogens in human clinical fluid samples by the use of ATP bioluminescence. We developed an ATP bioluminescence assay that eliminates somatic sources of ATP to selectively quantify the bacterial load in clinical urine specimens with a sensitivity of ATP bioluminescence assay for determination of the antimicrobial susceptibilities of uropathogens in clinical urine specimens tested in a blinded manner. ATP bioluminescent bacterial density quantitation was used to determine the inoculation volume in growth medium with and without antibiotics. After incubation at 37 degrees C for 120 min, the ATP bioluminescence assay was repeated to evaluate the uropathogen response to antibiotics. The ability of the ATP bioluminescence assay to discriminate between antimicrobial susceptibility and resistance was determined by comparison of the results obtained by the ATP bioluminescence assay with the results obtained by standard clinical microbiology methods. Receiver operator characteristic curves were used to determine the optimal threshold for discriminating between susceptibility and resistance. Susceptibility and resistance were correctly predicted in 87% and 95% of cases, respectively, for an overall unweighted accuracy of 91%, when the results were stratified by antibiotic. For samples in which the pathogen was susceptible, the accuracy improved to 95% when the results for samples with less than a 25-fold increase in the amount of bacterial ATP in the medium without antibiotics were excluded. These data indicate that a rapid bioluminescent antimicrobial susceptibility assay may be useful for the management of urinary tract infections.
M John Albert
Full Text Available Background & objectives: There is an increasing frequency of resistance of Campylobacter jejuni to antimicrobial agents making treatment difficult. In this study, the in vitro susceptibility of C. jejuni isolates collected over an eight year period was tested against tigecycline, a glycylcycline, the previously tested antimicrobial agents in Kuwait, ciprofloxacin, erythromycin and tetracycline, and other antimicrobial agents not previously tested in Kuwait, amoxicillin-clavulanic acid, gentamicin, imipenem and meropenem. Methods: A total of 97 C. jejuni isolates from diarrhoeal stools of Kuwaiti patients during 2002-2010 were studied for susceptibility to the above antimicrobial agents by E test. Results: Erythromycin resistance increased from 5.0 per cent in 2002-2003 to 13.8 per cent in 2007-2010. The figures for ciprofloxacin resistance for the same periods were 53 and 65.5 per cent, respectively. Tetracycline resistance increased from 40.0 per cent in 2003-2006 to 62.1 per cent in 2007-2010 (P=0.05. However, all isolates were uniformly susceptible to tigecycline and other antimicrobial agents. Interpretation & conclusions: There was a progressive increase in the prevalence of resistance to ciprofloxacin, erythromycin and tetracycline. As all isolates were uniformly susceptible to tigecycline, this antimicrobial agent can be considered as a potential candidate for treatment in clinical studies.
and Prevmtive Medicine Unit Two. Norfolk, Virginia’ Hospital Naciorwl Daniel Alcides Carrion , Callao, Pent~; Hospital Arzobi5po Loayza, Lima, Peru5...Alcides Carrion (Callao, Peru). All cultures, species identification, and antimicrobial suscep- tibility tests were performed in the Bacteriology
Full Text Available Background The epidemiology of Uropathogenic Escherichia coli (UPEC in urban and rural communities in Iran was never investigated prior to this study. Objectives The aims of this study were to detect the frequency of virulence genes and determine the antimicrobial susceptibility and phylogenetic background of Escherichia coli isolates collected from urban and rural communities. Materials and Methods A total of 100 E. coli isolates were collected from urine samples of patients with urinary tract infections (UTIs residing in two different locations, and confirmed by current biochemical tests. The phylogenetic groups were determined by the triplex-polymerase chain reaction (PCR method, and multiplex PCRs were used to detect eight Vf genes (fimH, iucD, irp2, hlyA, ompT, iha, iroN, and cnf1. The susceptibility profile of E. coli isolates was determined by the disk diffusion method. Results Ninety-five percent of UPEC showed at least one of the virulence genes, the most prevalent being fimH (95%, followed by irp2 (89%, iucD (69%, ompT (67%, iroN (29%, and iha (29%. The various combinations of detected genes were designated as virulence patterns. Phylogenetic groups, B2 (55% and D (22%, comprised the majority of isolated strains. Phenotypic tests showed that 92%, 74% and 71% of the isolates were resistant to ampicillin, ceftizoxime and cefixime, respectively. Conclusions These findings indicate that the UPEC isolates had eight virulence factors with high frequencies. Moreover, these results suggest a direct connection between virulence factors, gene diversity, phylogenetic background, and antimicrobial resistance in UPEC isolates.
Qi, Jing; Li, Lulu; Du, Yijun; Wang, Shourong; Wang, Jinwen; Luo, Yanbo; Che, Jie; Lu, Jinxing; Liu, Hui; Hu, Guangchun; Li, Jixia; Gong, Yanwen; Wang, Guisheng; Hu, Ming; Shiganyan; Liu, Yuqing
The biological characteristics and molecular epidemiology of Pseudomonas aeruginosa associated with mink hemorrhagic pneumonia from Shandong province of eastern China were determined in this study. From 2010 to 2011, 30 mink P. aeruginosa isolates were identified from lung, fecal and feed samples of clinical cases and subjected to serotyping, antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE) using SpeI. The P. aeruginosa isolates belonged to four serotypes-21 of type G, four of type I, three of type M, one of type B, and one non-typable strain. The strains were divided into four large groups as determined by PFGE. Isolates from the group 2 were highly homologous and were obtained from the same region as an epidemic. All of the isolates were sensitive to piperacillin, piperacillin/tazobactam, ceftazidime, cefepime, imipenem, amikacin, gentamicin and tobramycin and resistant to ampicillin, cefuroxime and cefuroxime axetil. A high frequency of resistance was found to ampicillin/sulbactam, cefazolin, cefotetan, ceftriaxone, nitrofurantoin, and trimethoprim/sulfamethoxazole (96.7%). Resistance to ticarcillin/clavulanic acid, ciprofloxacin and levofloxacin was less common (13.3%). There was no relationship between antibiotic resistance and serotype distribution of the isolates. The epidemic serotype of P. aeruginosa from the mink hemorrhagic pneumonia in Shandong province was type G, which was a clone of commonly found in this province. These findings reveal the genetic similarities and antimicrobial susceptibility profiles of P. aeruginosa from clinical cases of mink hemorrhagic pneumonia and will facilitate the prevention and control of the disease in Shandong province of China.
Maria Helena Féres Saad
Full Text Available Twenty-one Mycobacterium avium multisolates, from ten human immunodeficiency virus-infected patients, were typed by restriction fragment length polymorphism using as marker the IS1245 and characterized by minimum inhibitory concentration for nine different antibiotics. Two out of four patients harboring multisolates with different fingerprint profile, were therefore considered as having a polyclonal infection, since their isolates were taken from sterile site. This result confirms that polyclonal infection caused by M. avium occurs with a nonnegligenciable frequency. Analyzing the multisolates susceptibility profile of each patient it was observed that most of them were infected with strains having appreciably different antimicrobial susceptibility patterns, no matter what the genotypic pattern of the strains was. These results have strong implication for the treatment of the patients.
Bruno Horta Andrade
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.
Wang, Ching-Min; Lai, Chih-Cheng; Tan, Che-Kim; Huang, Yu-Chuang; Chung, Kuei-Pin; Lee, Meng-Rui; Hwang, Kao-Pin; Hsueh, Po-Ren
Human infections due to Roseomonas species are uncommon and the vast majority of reported infections are opportunistic and easy to treat. We retrospectively reviewed the computerized database of the Bacteriology Laboratory at the National Taiwan University Hospital to identify patients with infections caused by Roseomonas species during the period January 2000 to December 2010. Isolates of Roseomonas species were confirmed by 16S rRNA gene sequencing analysis. During the study period, 20 patients had cultures positive for Roseomonas species. R. mucosa was the most prevalent isolate (n = 18), followed by 1 each of R. gilardii and Roseomonas genomospecies 5. True infection caused by Roseomonas species was confirmed in 17 (85%) patients. Most (n = 12, 71%) of these infections were health care-associated infection. The majority of the patients (n = 12, 71%) had underlying diseases. Malignancy was the most common underlying disease, and catheter-related bloodstream infection was the most common type of infection. The antimicrobial susceptibility patterns varied among the different Roseomonas species. In conclusion, Roseomonas species can cause infection in children and adults regardless of immune status. Because different Roseomonas species may have different clinical features and susceptibility profiles, molecular studies are necessary to identify Roseomonas isolates to the species level.
Barbosa Pauletti, Rebeca; Reinato Stynen, Ana Paula; Pinto da Silva Mol, Juliana; Seles Dorneles, Elaine Maria; Alves, Telma Maria; de Sousa Moura Souto, Monalisa; Minharro, Silvia; Heinemann, Marcos Bryan; Lage, Andrey Pereira
This study aimed to determine the susceptibility profile of Brazilian Brucella abortus isolates from cattle to eight antimicrobial agents that are recommended for the treatment of human brucellosis and to correlate the susceptibility patterns with origin, biotype and MLVA16-genotype of the strains. Screening of 147 B. abortus strains showed 100% sensitivity to doxycycline and ofloxacin, one (0.68%) strain resistant to ciprofloxacin, two strains (1.36%) resistant to streptomycin, two strains (1.36%) resistant to trimethoprim-sulfamethoxazole and five strains (3.40%) resistant to gentamicin. For rifampicin, three strains (2.04%) were resistant and 54 strains (36.73%) showed reduced sensitivity. Two strains were considered multidrug resistant. In conclusion, the majority of B. abortus strains isolated from cattle in Brazil were sensitive to the antimicrobials commonly used for the treatment of human brucellosis; however, a considerable proportion of strains showed reduced susceptibility to rifampicin and two strains were considered multidrug resistant. Moreover, there was no correlation among the drug susceptibility pattern, origin, biotype and MLVA16-genotypes of these strains.
Schuetz, Audrey N
Infections due to anaerobic bacteria can be severe and life-threatening. Susceptibility testing of anaerobes is not frequently performed in laboratories, but such testing is important to direct appropriate therapy. Anaerobic resistance is increasing globally, and resistance trends vary by geographic region. An overview of a variety of susceptibility testing methods for anaerobes is provided, and the advantages and disadvantages of each method are reviewed. Specific clinical situations warranting anaerobic susceptibility testing are discussed.
Fredborg, M; Rosenvinge, F S; Spillum, E;
Rapid antimicrobial susceptibility testing (AST) is essential for early and appropriate therapy. Methods with short detection time enabling same-day treatment optimisation are highly favourable. In this study, we evaluated the potential of a digital time-lapse microscope system, the oCelloScope s......Rapid antimicrobial susceptibility testing (AST) is essential for early and appropriate therapy. Methods with short detection time enabling same-day treatment optimisation are highly favourable. In this study, we evaluated the potential of a digital time-lapse microscope system, the o...... (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...
Rodrigo Otávio Silveira Silva
Full Text Available The objective of this study was to evaluate antimicrobial susceptibility in Clostridium difficile strains isolated from animals and humans in Brazil. The 54 C. difficile strains used were isolated from stool samples from piglets (n=16, dogs (n=13, humans (n=13, foals (n=8 calves (n=2, an ocelot (n=1 and a maned wolf (n=1. Antimicrobial susceptibility was determined using the serial plate agar dilution method for penicillin, florfenicol, oxytetracycline, erythromycin, vancomycin, metronidazole and tylosin. The C. difficile strains assessed were susceptible to metronidazole and vancomycin. Florfenicol resistance was rarely observed; 52 (96.4% strains were sensitive to this antimicrobial. Five (9.3%, five (9.3%, 14 (25.9% and 20 (37.0% strains were resistant to oxytetracycline, penicillin, tylosin and erythromycin respectively.
Aguila, Adalberto; Bernedo, Robert; Llop, Alina; Ramírez, Margarita; Bravo, Laura; Fernández, Anabel; Ledo, Yudith
Forty strains of Escherichia coli isolated from children under 5 years of age with acute diarreas, coming from different provinces of the country , were analyzed. Four important phenotypical determinants were tested: sorbosa, sorbitol, enterohemolysin and 0157:H7 serology, in order to select those strains from enterohemorrhagic or Shiga toxin-producing category. Likewise, they were characterized by biotyping and antimicrobial susceptibility methods. The use of phenotypical tests showed six strains with presumptive characteristics, four of which were most likely to be Shiga toxin-producing strains. In antimicrobial susceptibility test, the strains showed high resistance mainly to ampicillin and trimethrophin-sulfamethoxasole. Another interesting finding were intermediate resistance and susceptibility values to augmentin, aztreonan and ceftriaxone. There were 12 antimicrobial resistance patterns of which 10 were multi-resistant.
Khamis, Abdullah M.
Motivation: The increased prevalence of multi-drug resistant (MDR) pathogens heightens the need to design new antimicrobial agents. Antimicrobial peptides (AMPs) exhibit broad-spectrum potent activity against MDR pathogens and kills rapidly, thus giving rise to AMPs being recognized as a potential substitute for conventional antibiotics. Designing new AMPs using current in-silico approaches is, however, challenging due to the absence of suitable models, large number of design parameters, testing cycles, production time and cost. To date, AMPs have merely been categorized into families according to their primary sequences, structures and functions. The ability to computationally determine the properties that discriminate AMP families from each other could help in exploring the key characteristics of these families and facilitate the in-silico design of synthetic AMPs. Results: Here we studied 14 AMP families and sub-families. We selected a specific description of AMP amino acid sequence and identified compositional and physicochemical properties of amino acids that accurately distinguish each AMP family from all other AMPs with an average sensitivity, specificity and precision of 92.88%, 99.86% and 95.96%, respectively. Many of our identified discriminative properties have been shown to be compositional or functional characteristics of the corresponding AMP family in literature. We suggest that these properties could serve as guides for in-silico methods in design of novel synthetic AMPs. The methodology we developed is generic and has a potential to be applied for characterization of any protein family.
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
Full Text Available Introduction: Uropathogenic Escherichia coli (UPEC rely on the correlation of virulence expression with antimicrobial resistance to persist and cause severe urinary tract infections (UTIs. Objectives: We assessed the virulence pattern and prevalence among UPEC strains susceptible and resistant to multiple antimicrobial classes. Methods: A total of 174 non-duplicate UPEC strains from patients with clinically significant UTIs were analysed for susceptibility to aminoglycoside, antifolate, cephalosporin, nitrofuran and quinolone antibiotics for the production of extended-spectrum β-lactamases and for the presence of six virulence determinants encoding adhesins (afimbrial, Type 1 fimbriae, P and S-fimbriae and toxins (cytotoxic necrotising factor and haemolysin. Results: Relatively high resistance rates to nalidixic acid, ciprofloxacin, cephalothin and trimethoprim-sulfamethoxazole (82%, 78%, 62% and 59%, respectively were observed. Fourteen distinct patterns were identified for the virulence determinants such as afaBC, cnfI, fimH, hylA, papEF and sfaDE. The toxin gene, cnfI (75.3%, was the second most prevalent marker to the adhesin, fimH (97.1%. The significant association of sfaDE/hylA (P < 0.01 among antimicrobial resistant and susceptible strains was also observed notwithstanding an overall greater occurrence of virulence factors among the latter. Conclusions: This study provides a snapshot of UPEC complexity in Jamaica and highlights the significant clonal heterogeneity among strains. Such outcomes emphasise the need for evidence-based strategies in the effective management and control of UTIs.
Cantón, Rafael; Alós, Juan Ignacio; Baquero, Fernando; Calvo, Jorge; Campos, José; Castillo, Javier; Cercenado, Emilia; Domínguez, M Angeles; Liñares, Josefina; López-Cerezo, Lorena; Marco, Francesc; Mirelis, Beatriz; Morosini, María-Isabel; Navarro, Ferran; Oliver, Antonio; Pérez-Trallero, Emilio; Torres, Carmen; Martínez-Martínez, Luis
The number of clinical microbiology laboratories that have incorporated automatic susceptibility testing devices has increased in recent years. The majority of these systems determine MIC values using microdilution panels or specific cards, with grouping into clinical categories (susceptible, intermediate or resistant) and incorporate expert systems to infer resistance mechanisms. This document presents the recommendations of a group of experts designated by Grupo de Estudio de los Mecanismos de Acción y Resistencia a los Antimicrobianos (GEMARA, Study group on mechanisms of action and resistance to antimicrobial agents) and Mesa Española de Normalización de la Sensibilidad y Resistencia a los Antimicrobianos (MENSURA, Spanish Group for Normalizing Antimicrobial Susceptibility and Antimicrobial Resistance), with the aim of including antimicrobial agents and selecting concentrations for the susceptibility testing panels of automatic systems. The following have been defined: various antimicrobial categories (A: must be included in the study panel; B: inclusion is recommended; and C: inclusion is secondary, but may facilitate interpretative reading of the antibiogram) and groups (0: not used in therapeutics but may facilitate the detection of resistance mechanisms; 1: must be studied and always reported; 2: must be studied and selectively reported; 3: must be studied and reported at a second level; and 4: should be studied in urinary tract pathogens isolated in urine and other specimens). Recommended antimicrobial concentrations are adapted from the breakpoints established by EUCAST, CLSI and MENSURA. This approach will lead to more accurate susceptibility testing results with better detection of resistance mechanisms, and allowing to reach the clinical goal of the antibiogram.
Belay Anagaw; Chandrashekhar Unakal; Mucheye Gezachew; Fantahun Biadgelgene; Berhanu Anagaw; Tariku Geleshe; Birke Taddese; Birhanu Getie; Mengistu Endris; Andargachew Mulu
Objective:To assess the magnitude and antimicrobial susceptibility patterns of Streptococcus pneumoniae isolates from various clinical specimens. Methods:A record based on retrospective study was conducted at Gondar University Teaching Hospital from September 2007 to January 2012. All patients who visited Gondar University Hospital and provided clinical specimens (body fluids, discharge, swab and blood) for routine bacteriological culturing and antimicrobial susceptibility testing were taken for analysis. Clinical specimens were processed for bacterial culture according to the standard procedures. Antimicrobial susceptibility test for isolated organisms was done using agar disk diffusion method. The data were entered and analyzed using SPSS software version 16 package. Results: One hundred and fifty three Streptococcus pneumoniae were isolated from patients who visited Gondar University Teaching Hospital bacteriology laboratory for culture. Majority of the pneumococcal isolates were from inpatients [111(72.5%)], and 74(48.4%) were from body fluids. Out of the total isolates, 93(61%) were found to be resistant to at least one antibiotic used for susceptibility testing. Forty eight (43.2%) of the isolates were multi-drug resistant (resistant to two or more drugs). The resistance rate noted for both ciprofloxacin 17(11.1%) and ceftriaxone 15(9.8%) were alarming. Conclusions: High proportions of the isolates tend to be increasingly resistant to the commonly prescribed drugs. The recommended drug of choice like ciprofloxacin and ceftriaxone were found to be less susceptible in the study area. Based on the findings, we therefore recommend that antimicrobial agents should be inspected for acceptable activity before they are prescribed and administered empirically. Further study with a better design and survey of antimicrobial susceptibility at large scale shoule be performed to draw advanced information.
Full Text Available Staphylococcus aureus is 1 of the most important causes of bovine mastitis and is responsible for significant economic losses to the dairy industry worldwide. One of the principal approaches used in treating intramammary infections is the administration of antimicrobials. Due to the propensity of S. aureus to develop resistance, antimicrobial susceptibility monitoring is necessary to ensure that treatment regimens are effective. As part of this investigation, 90 S. aureus strains isolated from mastitis cases submitted to Allerton Provincial Veterinary Laboratory during 2008 and 2009 were evaluated for their susceptibility to a panel of 10 antimicrobials. Only 8 of the 90 S. aureus isolates tested (8.9 % were found to be susceptible to all of the antimicrobials evaluated. A very high level of resistance to the beta-lactam antibiotics was noted: 47.8 % of the isolates were resistant to penicillin and 65.6 % were resistant to ampicillin. Minimal resistance to oxacillin, cephalothin and trimethoprim-sulfamethoxazole (1.1 % was found. Seventeen (18.9 % of the isolates tested were found to be resistant to 3 or more antimicrobials. The need for vigilant monitoring of bacterial resistance trends in the dairy industry is warranted as the potential public health implications are significant.
[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].
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
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.
The supplemental information presented in this document is intended for use with the antimicrobial susceptibility testing procedures published in the following Clinical and Laboratory Standards Institute (CLSI) approved documents VET03-A Methods for Antimicrobial Disk Susceptibility Testing of Bacte...
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
Deshmukh, A.; Hagen, F.; Sharabasi, O.A.; Abraham, M.; Wilson, G.; Doiphode, S.; Maslamani, M.A.; Meis, J.F.G.M.
BACKGROUND: Brucellosis is one of the most common zoonotic disease affecting humans and animals and is endemic in many parts of the world including the Gulf Cooperation Council region (GCC). The aim of this study was to identify the species and determine the antimicrobial susceptibility pattern of B
Emborg, Hanne-Dorthe; Baggesen, Dorte Lau; Aarestrup, Frank Møller
Objectives: This study analysed the trends in antimicrobial resistance in Salmonella serovars and phage types from pigs in Denmark from 1997 to 2006. Methods: Salmonella isolates collected through the Salmonella surveillance programme in pigs were serotyped and phage-typed, and susceptibilities t...
Brazier, J; Chmelar, D; Dubreuil, L
Gram-positive anaerobic cocci (GPAC) are a heterogeneous group of microorganisms frequently isolated from local and systemic infections. In this study, the antimicrobial susceptibilities of clinical strains isolated in 10 European countries were investigated. After identification of 299 GPAC to s...
Moller, LVM; Regelink, AG; Grasselier, H; van Alphen, L
We analyzed the antimicrobial susceptibilities of Haemophilus influenzae isolates from 157 sputum specimens prospectively collected from 39 cystic fibrosis (CF) patients during a 2-year study, These isolates were characterized by random amplified polymorphic DNA analysis and major outer membrane pro
Alastruey-Izquierdo, Ana; Alcazar-Fuoli, Laura; Cuenca-Estrella, Manuel
The use of molecular tools has led to the description of new cryptic species among different Aspergillus species complexes. Their frequency in the clinical setting has been reported to be between 10 and 15%. The susceptibility to azoles and amphotericin B of many of these species is low, and some of them, such as Aspergillus calidoustus or Aspergillus lentulus, are considered multi-resistant. The changing epidemiology, the frequency of cryptic species, and the different susceptibility profiles make antifungal susceptibility testing an important tool to identify the optimal antifungal agent to treat the infections caused by these species.
Sampimon, O.C.; Lam, T.G.J.M.; Mevius, D.J.; Schukken, Y.H.; Zadoks, R.N.
The aim of this study was to examine whether antimicrobial resistance profiles of coagulase-negative Staphylococcus (CNS) species isolated from milk of dairy cows differed between bacterial species, and to compare results obtained by phenotypic and genotypic profiling of resistance to penicillin, ox
Belard, Sabine; Toepfner, Nicole; Capan-Melser, Mesküre; Mombo-Ngoma, Ghyslain; Zoleko-Manego, Rella; Groger, Mirjam; Matsiegui, Pierre-Blaise; Agnandji, Selidji T; Adegnika, Ayôla A; González, Raquel; Kremsner, Peter G; Menendez, Clara; Ramharter, Michael; Berner, Reinhard
Neonatal invasive disease due to Streptococcus agalactiae is life threatening and preventive strategies suitable for resource limited settings are urgently needed. Protective coverage of vaccine candidates based on capsular epitopes will relate to local epidemiology of S. agalactiae serotypes and successful management of critical infections depends on timely therapy with effective antibiotics. This is the first report on serotype distribution and antimicrobial susceptibility of S. agalactiae in pregnant women from a Central African region. Serotypes V, III, and Ib accounted for 88/109 (81%) serotypes and all isolates were susceptible to penicillin and clindamycin while 13% showed intermediate susceptibility to erythromycin.
Justesen, U S; Acar, Ziyap; Olsson, K;
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....
Zhang, Lili; Li, Yuchen; Bao, Hongduo; Wei, Ruicheng; Zhou, Yan; Zhang, Hui; Wang, Ran
Staphylococcus aureus is a significant bacterial pathogen associated with bovine mastitis. The aim of the present study was to investigate and characterize of S. aureus strains isolated from the milk of cows suffering from mastitis in the mid-east of China. Among the 200 milk samples analyzed, 58 were positive for S. aureus, of these isolates, 11 isolates were methicillin-resistant Staphylococcus aureus (MRSA). All of the 58 S. aureus strains were classified in agr group I, while seven different sequence type (ST) patterns were identified and among them the most common was ST630 followed by ST188. All of the S. aureus isolates belonging to ST630 were resistant to more than four antimicrobials, and 22.2% of isolates belonging to ST188 were resistant to eight antimicrobials. Interestingly, while strong biofilm producers demonstrated higher resistance to multiple antimicrobials, they exhibited lower intracellular survival rates. The results of this study illustrated the distribution, antimicrobial susceptibility profiles, genotype, and the ability of biofilm production and mammary epithelial cells invasion of these S. aureus isolates. This study can provide the basis for the development of a disease prevention program in dairy farms to reduce the potential risk in both animal and human health.
units as part of the Canadian National Intensive Care Unit study. Diagn Microbiol Infect Dis 2008;61(2:217-21. 13. Livermore DM. Of Pseudomonas , porins, pumps and carbapenems. J Antimicrob Chemother 2001;47(3:247-50. 14. Navneeth BV, Sridaran D, Sahay D, Belwadi MR. A preliminary study on metalloβ- lactamase producing Pseudomonas aeruginosa in hospitalized patients. Indian J Med Res 2002;116:26, 4-7. 15. Büscher KH, Cullmann W, Dick W, Opferkuch W. Imipenem resistance in Pseudomonas aeruginosa resulting from diminished expression of an outer membrane protein. Antimicrob Agents Chemother 1987;31(5:703–8. 16. Strateva T, Ouzounova-Raykova V, Markova B, Todorova A, Marteva-Proevska Y, Mitov I. Problematic clinical isolates of Pseudomonas aeruginosa from the university hospitals in Sofia, Bulgaria: current status of antimicrobial resistance and prevailing resistance mechanisms. J Med Microbiol 2007;56(7:956-63. 17. Mohajeri P. Antibiotic susceptibility and resistance patterns of pseudomonas aeruginosa strains isolated from different clinical specimens in patients referred to the teaching hospitals in Kermanshah (2001-2. Behbood Res J Kermanshah Univ Med Sci 2004;7(4:11-20. (Full Text in Persian 18. Streit JM, Jones RN, Sader HS, Fritsche TR. Assessment of pathogen occurrences and resistance profiles among infected patients in the intensive care unit: report from the Sentry Antimicrobial Surveillance Program (North America, 2001. Int J Antimicrob Agents 2004;24(2:111-8. 19. Shacheraghi F, Shakibaie MR, Noveiri H. Molecular Identification of ESBL Genes blaGES-1, blaVEB-1, blaCTX-M blaOXA-1, blaOXA-4, blaOXA-10 and blaPER-1 in Pseudomonas aeruginosa Strains Isolated from Burn Patients by PCR, RFLP and Sequencing Techniques. Int J Biol life Sci 2010;3(6:138-42. 20. Fazeli H, Moslehi Tekantapeh Z, Irajian GHR, Salehi M. Determination of drug resistance patterns and detection of bla-vim gene in pseudomonas aeruginosa strains isolated from burned patients in the Imam Mosa
Staphylococcus aureus: incidência e resistência antimicrobiana em abscessos cutâneos de origem comunitária Staphylococcus aureus: etiology and susceptibility profile to antimicrobial agents of skin and subcutaneous cell tissue abscesses from community infections
Martin Zavadinack Netto
profilaxia ou tratamento de infecções por S.aureus, mesmo aqueles de origem comunitária.An analysis of Staphylococcus aureus (Monera, an etiological agent of community infections, is provided. Staphylococcus aureus causes the formation of skin and subcutaneous cell tissue abscesses. Susceptibility profile to antimicrobials used in prophylaxis or therapy of these cutaneous infections will be given. One hundred and seven samples of secretions were collected from January 1996 through July 1997 at the emergency sector of University Hospital of the State University of Maringá, Maringá, state of Paraná, Brazil, from infected patients with skin and subcutaneous cell tissue abscesses. Microbiological evaluation was carried out according to Bayle and susceptibility to antimicrobial was evaluated in vitro through the technique of diffusion in agar according to Kirby. Sixteen antimicrobials used in prophylaxis or therapy of skin and subcutaneous cell tissue infections were evaluated. From the one hundred and seven clinical samples collected from patients complaining of infections with skin and subcutaneous cell tissue abscesses, 71 (66.35% were positive to S.aureus and 36 (33,65% were either positive for other microorganisms, or tested negative. In the evaluation of susceptibility to S.aureus a higher sensitivity to vancomycin (100%, teicoplanin (100%, amikacin (100%, cefoxitin (100%, cephalothin (98.53%, lincomycin (98.53%, gentamicin (98.53%, oxacillin (96,4%, norfloxacin (95.77% and sulfazotrin (95.77% was found when compared to penicillin G (08.45%, ampicillin (08.45%, kanamycin (81,69%, erythromycin (88.41%, tetracycline (90.14 and chloramphenicol (94,36%. Results show that S.aureus is the most frequently isolated microorganism from community infections with skin and subcutaneous tissue abscesses. The susceptibility profile evidences high resistance to penicillins, which restricts the use of these antimicrobials as an alternative in the prophylaxis or treatment of S
Sherwood Julie S
Full Text Available Abstract Background Campylobacter is a major cause of human disease worldwide and poultry are identified as a significant source of this pathogen. Most disease in humans is associated with the consumption of contaminated poultry or cross-contamination with other foods. The primary drugs of choice for treatment of human campylobacteriosis include erythromycin and ciprofloxacin. In this study, we investigated the prevalence of resistance to erythromycin and ciprofloxacin in Campylobacter isolates recovered from turkey carcasses at two processing plants in the Upper Midwest US. Further analysis of a subset of isolates was carried out to assess resistance and genotype profiles. Results Campylobacter isolates from plant A (n = 439; including 196 C. coli and 217 C. jejuni and plant B (n = 362, including 281 C. coli and 62 C. jejuni were tested for susceptibility to ciprofloxacin and erythromycin using agar dilution. C. coli were more frequently resistant than C. jejuni in both plants, including resistance to ciprofloxacin (28% of C. jejuni and 63% of C. coli, plant B; and 11% of C. coli, plant A. Erythromycin resistance was low among C. jejuni (0% plant A and 0.3% plant B compared to C. coli (41%, plant A and 17%, plant B. One hundred resistant and susceptible isolates were selected for additional antimicrobial susceptibility testing, restriction fragment length polymorphism analysis of the flaA gene (fla typing, and pulsed-field gel electrophoresis (PFGE. Fla-PFGE types obtained (n = 37 were associated with a specific plant with the exception of one type that was isolated from both plants. C. coli isolates (n = 65 were grouped into 20 types, while C. jejuni isolates (n = 35 were grouped into 17 types. Most isolates with identical fla-PFGE patterns shared identical or very similar antimicrobial resistance profiles. PFGE alone and composite analysis using fla-PFGE with resistance profiles separated C. jejuni and C. coli into distinct groups. Conclusion
Full Text Available (Received 25 Nov, 2008 ; Accepted 4 Mar, 2009AbstractBackground and purpose: Brucellosis is a zoonotic disease with worldwide distribution that is endemic in Iran. Worldwide, brucellosis remains a major cause of morbidity in humans and domesticated animals. The disease has a wide spectrum of clinical manifestation and can affect a variety of organs and systems. This study focused on blood culture of serologic diagnosed brucellosis and antimicrobial susceptibility test.Materials and methods: In this cross sectional study, microbiologic survey was done on a total of 30 serum samples with STA titer of 1:160 or greater and 2ME titer of 1:40 or greater, which were presumptive for brucellosis. Blood cultures were done by lysis centrifugation and antimicrobial susceptibility test, against 9 antimicrobial agents by disk method. The data was analyzed by stata V8.0 software.Results: At the end this study, the blood culture isolation rate was 23.3 %( 7 cases out of 30 patients and all of the isolates were brucella melitensis. Antimicrobial susceptibility tests showed high in vitro activity of ofloxacin, ciprofloxacin and doxycycline and also, low in vitro activity of streptomycin and cotrimoxazole.Conclusion: Brucellosis is endemic in Iran. Brucella melitensis was the most common strain of brucella in our patients. Except cotrimoxazole and streptomycin, high in vitro activity was found with other antibrucella agents, especially with ofloxacin, ciprofloxacin and doxycycline. J Mazand Univ Med Sci 2009; 19(68: 74-78 (Persian
Nijs, A; Cartuyvels, R; Mewis, A; Peeters, V; Rummens, J L; Magerman, K
The Osiris and Sirscan 2000 systems are two semiautomated systems that can be used to read and interpret the results on disk diffusion agar plates. They are both used for determination of susceptibility to antimicrobial agents. The present study compared both systems versus the NCCLS standard method of visual reading with a ruler. Both inpatient and outpatient samples with a total of 315 nonfastidious gram-negative strains were obtained. In total, 3724 organism-antimicrobial agent combinations that fulfilled the NCCLS guidelines for disk diffusion susceptibility testing were evaluated prospectively. The results obtained with both systems in comparison with those obtained by the classical nonautomated means of interpretation were excellent, with correlation coefficients of 0.96 for both systems. The overall agreements for susceptibility interpretation were 96.56 and 96.24% with the Osiris and Sirscan systems, respectively. Very major errors were obtained for 8 (1.07%) and 10 (1.34%) organism-antimicrobial agent combinations with the Osiris and Sirscan systems, respectively. In addition, major errors were obtained for 2 (0.07%) and 6 (0.21%) combinations with the Osiris and Sirscan systems, respectively. Minor errors were obtained for 118 and 124 organism-antimicrobial agent combinations with the Osiris and Sirscan systems, respectively. Overall, both the Osiris system and the Sirscan system are comparable and reliable systems for determination of interpretative categories from the zone diameters of standard disk diffusion test plates.
Yash Pal Chugh
Full Text Available The present study was conducted to find out the prevalence and spectrum of Gram negative pathogens causing bacterial meningitis and their antimicrobial susceptibility pattern in a tertiary care hospital. The cerebrospinal fluid (CSF (3-5 ml was collected from 638 admitted children clinically suspected of septic meningitis. Bacterial isolates were identified and antimicrobial susceptibility was assessed by the Kirby-Bauer disk diffusion method. Of the 638 samples tested 102 (15.99% were culture positive. Male to female (M:F ratio was 1.62:1. The maximum incidence of 45 (44.12% cases was found in children (1-12 yrs; in institutional deliveries the incidence was 58 (56.86% cases. Further, the incidence of 51 cases was found from May to August. Escherichia coli (E. coli were commonest, seen in 9 (25% cases followed by Acinetobacter spp., Citrobacter spp. and Klebsiella spp. with 6 (16.67% cases each. Enterobacter spp., Neisseria spp. and Pseudomonas aeruginosa were isolated in 3 (8.33% cases each. E. coli, Acinetobacter spp, Citrobacter spp and Klebsiella spp isolates were 100% susceptible to meropenem, piperacillin-tazobactam and cefoperazone-sulbactam and 100% resistant to cotrimoxazole and tetracycline. All strains of Neisseria spp, Enterobacter spp and Pseudomonas spp. were 100% susceptible to meropenem followed by gatifloxacin. These were 100% resistant to tetracycline and cotrimoxazole. Neisseria spp. were also 100% susceptible to pristinamycin. In septic meningitis Gram negative organisms are less common (35.29%. Of the isolates, more common Gram negative isolates included E. coli, Acinetobacter Spp., Citrobacter Spp., and Klebsiella spp. and these isolates were 100% susceptible to meropenem, piperacillin-tazobacatam and cefoperazone-sulbactam. Hence, empirical therapy should be formulated according to antimicrobial susceptibility patterns.
Evans, N J; Brown, J M; Hartley, C; Smith, R F; Carter, S D
Digital dermatitis (DD) is a major infectious lameness of dairy cattle and sheep considered to be caused by treponemes. The aim of this study was to identify antibiotics effective against DD treponemes that might be useful in the treatment of ruminant DD in the future or to identify antibiotics useful in isolation studies. Here, a microdilution method was used to identify in vitro antimicrobial susceptibility of treponemes cultured from DD lesions to eight relevant antibiotics. DD treponemes exhibited highest susceptibility to amoxicillin, azithromycin and gamithromycin. Unfortunately, amoxicillin whilst having potential for DD treatment in other animals (e.g. sheep) would require milk withhold periods in dairy cattle. DD treponemes were not particularly susceptible to two cephalosporins: cefalexin and ceftiofur, which do not require milk withhold. The bacteria demonstrated low susceptibility to trimethoprim and especially colistin suggesting these antimicrobials may be particularly useful in isolation of DD treponemes. The most promising high susceptibility results for macrolides indicate a rationale to consider veterinary licensed macrolides as DD treatments. Furthermore, given the DD treponeme antibiotic susceptibility similarities to established treatments for human treponematoses, identification of treponemacidal, long acting β-lactam analogues not requiring milk withhold may allow for development of a successful treatment for dairy cattle DD.
Gismondi, Pierpacifico; Maffini, Valentina; Bizzarri, Barbara; Fornaroli, Fabiola; Madia, Carmen; Salerno, Antonino; Cangelosi, A. Marta; de'Angelis, Gian Luigi
The eradication therapy of Helicobacter pylori (H. pylori) infection is still a challenge for gastroenterologists. One of the main causes of failure in H. pylori eradication is the antibiotic resistance mainly to clarithromycin. Culture from biopsies is maybe the most used method among the antimicrobial susceptibility techniques. In this study, we compared the antimicrobial susceptibility changes in children with H. pylori infection over 13 years and we confirmed that clarithromycin resistance has been increased (16% versus 26%) though with no statistically signficant value. Therefore, clarithromycin should not be used in empiric treatment of H. pylori eradication therapy in children, but its use should be limited only to children with known antimicrobial susceptibility. On the other hand, metronidazole resistance has decreased over this time period in statistically significant manner (56% versus 33%, p = 0.014). Furthermore, ampicillin resistance has been confirmed to be very rare (3% versus 0%) in children with H. pylori infection. In conclusion, in H. pylori infection, if we do not know the antibiotic susceptibility of patients, we should recommend an eradication therapy based on the local distribution of antibiotic resistance rates trying to limit the therapeutic failures. PMID:26064096
Full Text Available Abstract: Introduction: The drug resistant Acinetobacter strains are important causes of nosocomial infections that are difficult to control and treat. This study aimed to determine the antimicrobial susceptibility patterns of Acinetobacter strains isolated from different clinical specimens obtained from patients belonging to different age groups. METHODS: In total, 716 non-duplicate Acinetobacter isolates were collected from the infected patients admitted to tertiary-care hospitals at Lahore, Pakistan, over a period of 28 months. The Acinetobacter isolates were identified using API 20E, and antimicrobial susceptibility testing was performed and interpreted according to Clinical and Laboratory Standards Institute (CLSI guidelines. RESULTS: The isolation rate of Acinetobacter was high from the respiratory specimens, followed by wound samples. Antibiotic susceptibility analyses of the isolates revealed that the resistance to cefotaxime and ceftazidime was the most common, in 710 (99.2% specimens each, followed by the resistance to gentamicin in 670 (93.6% isolates, and to imipenem in 651 (90.9% isolates. However, almost all isolates were susceptible to tigecycline, colistin, and polymyxin B. CONCLUSIONS: The present study showed the alarming trends of resistance of Acinetobacter strains isolated from clinical specimens to the various classes of antimicrobials. The improvement of microbiological techniques for earlier and more accurate identification of bacteria is necessary for the selection of appropriate treatments.
Mayrhofer, Sigrid; Zitz, Ulrike; Birru, Firew H; Gollan, Dagmar; Gołoś, Aleksandra K; Kneifel, Wolfgang; Domig, Konrad J
Lactobacilli play a crucial role as probiotics and as starter cultures in the production of fermented foods. Although lactobacilli are a technologically useful and beneficial group of bacteria, a few members of them have been rarely correlated with bacterial infections. Correspondingly, clinicians are interested in the antimicrobial susceptibility of lactobacilli. In addition, antimicrobial susceptibility testing (AST) is also relevant for commercially applied lactobacilli as bacterial strains harboring transferable antibiotic resistance genes should not be used in fermented and probiotic foods. Therefore, two methods were developed by different organizations, which were compared within this study. For this purpose, 22 Lactobacillus-type strains were tested for their antimicrobial susceptibility to 16 antibiotics following the procedures of the Clinical and Laboratory Standards Institute (CLSI) and the International Organization of Standardization (ISO)/International Dairy Federation (IDF). Crucial discrepancies between both procedures were detected mainly due to the different AST media. Hence, half of the strains tested did not consistently grow in the CLSI medium, whereas all showed evaluable growth in the ISO/IDF medium. However, some antibiotics were influenced by the latter medium. In particular, low levels of essential agreement between both methods were obtained with seven antibiotics. Accordingly, different interpretative criteria are needed for both procedures to distinguish resistant from susceptible strains.
Cameron, Marguerite; Saab, Matthew; Heider, Luke; McClure, J Trenton; Rodriguez-Lecompte, Juan Carlos; Sanchez, Javier
Determination of antimicrobial susceptibility of bovine mastitis pathogens is important for guiding antimicrobial treatment decisions and for the detection of emerging resistance. Environmental streptococci are ubiquitous in the farm environment and are a frequent cause of mastitis in dairy cows. The aim of the study was to determine patterns of antimicrobial susceptibility among species of environmental streptococci isolated from dairy cows in the Maritime Provinces of Canada. The collection consisted of 192 isolates identified in milk samples collected from 177 cows originating from 18 dairy herds. Results were aggregated into: (1) Streptococcus uberis (n = 70), (2) Streptococcus dysgalactiae (n = 28), (3) other Streptococci spp. (n = 35), (4), Lactococcus spp. (n = 32), and (5) Enterococcus spp. (n = 27). Minimum inhibitory concentrations (MICs) were determined using the Sensititre microdilution system and mastitis plate format. Multilevel logistic regression models were used to analyze the data, with antimicrobial susceptibility as the outcome. The proportion of susceptible S. uberis ranged from 23% (for penicillin) to 99% (for penicillin/novobiocin), with a median of 82%. All S. dysgalactiae were susceptible to all antimicrobials except for penicillin (93% susceptible) and tetracycline (18% susceptible). The range of susceptibility for other Streptococcus spp. was 43% (for tetracycline) to 100%, with a median percent susceptibility of 92%. Lactococcus spp. isolates displayed percent susceptibilities ranging from 0% (for penicillin) to 97% (for erythromycin), median 75%. For the antimicrobials tested, the minimum inhibitory concentrations were higher for Enterococcus spp. than for the other species. According to the multilevel models, there was a significant interaction between antimicrobial and bacterial species, indicating that susceptibility against a particular antimicrobial varied among the species of environmental streptococci and vice
Ocorrência de bactérias clinicamente relevantes nos resíduos de serviços de saúde em um aterro sanitário brasileiro e perfil de susceptibilidade a antimicrobianos Occurrence of clinically relevant bacteria in health service waste in a Brazilian sanitary landfill and antimicrobial susceptibility profile
Thiago César Nascimento
Full Text Available Os resíduos de serviços de saúde suscitam polêmica quanto a importância para a saúde humana, animal e ambiental. Avaliou-se a ocorrência de bactérias clinicamente relevantes na pilha de resíduos de serviços de saúde em um aterro sanitário e seu perfil de susceptibilidade aos antimicrobianos. Alíquotas de chorume foram processadas para isolamento seletivo de Staphylococcus sp, bastonetes Gram negativos da família Enterobacteriaceae e não fermentadores. Resistência bacteriana a todos os antimicrobianos testados foi observada em todos os grupos microbianos, além de resistência a mais de uma droga. Os resultados permitem sugerir que bactérias viáveis nos resíduos de serviços de saúde representam riscos à saúde humana e animal. Além disso, a ocorrência de linhagens multirresistentes sustenta a hipótese dos resíduos de serviços de saúde atuarem como reservatórios de marcadores de resistência, com impacto ambiental. A falta de legislação regional de segregação, tratamento e destino de resíduos podem expor diferentes populações a riscos de transmissão de doenças infecciosas associadas a microrganismos multirresistentes.Health service waste gives rise to controversy regarding its importance for human, animal and environmental health. Occurrences of clinically relevant bacteria in piles of health service waste in a sanitary landfill and their antimicrobial susceptibility profile were evaluated. Aliquots of leachate were processed for selective isolation of Staphylococcus sp, Gram-negative rods of the Enterobacteriaceae family and non-fermenters. Bacterial resistance to all the antimicrobials tested was observed in all microbial groups, including resistance to more than one drug. The results make it possible to suggest that viable bacteria in health service waste represent risks to human and animal health. Furthermore, occurrences of multiresistant strains support the hypothesis that health service waste acts as a
Paterna, A; Sánchez, A; Gómez-Martín, A; Corrales, J C; De la Fe, C; Contreras, A; Amores, J
This study examined the susceptibility to several antimicrobials of 28 isolates of Mycoplasma agalactiae obtained from goats in a region (southeastern Spain) where contagious agalactia is endemic. For each isolate, the minimum inhibitory concentration (MIC) against 12 antimicrobials of the quinolone, macrolide, aminoglycoside, and tetracycline families was determined. The antimicrobials with the lowest MIC were enrofloxacin, ciprofloxacin, tylosin, and doxycycline, all with MIC90 (concentration at which growth of 90% of the isolates is inhibited) <1 µg/mL. Norfloxacin (a quinolone) showed a wide MIC range (0.1-12.8 µg/mL), suggesting a resistance mechanism toward this antimicrobial that was not elicited by enrofloxacin or ciprofloxacin (the other quinolones tested). Erythromycin showed the highest MIC90 such that its use against Mycoplasma agalactiae is not recommended. Finally, Mycoplasma agalactiae isolates obtained from goat herds with clinical symptoms of contagious agalactia featured higher MIC90 and MIC50 (concentration at which growth of 50% of the isolates is inhibited) values for many of the antimicrobials compared with isolates from asymptomatic animals. The relationship between the extensive use of antimicrobials in herds with clinical contagious agalactia and variations in MIC requires further study.
Vivian G Loo
Full Text Available The minimal inhibitory concentrations (MICs of penicillin, tetracycline, erythromycin, cefoxitin, ceftriaxone and spectinomycin were determined for 300 consecutive strains of Neisseria gonorrhoeae collected from physicians’ offices in Ontario. Only four isolates were found to produce beta-lactamase. Of the remaining 296 isolates, five (1.7% had penicillin MICs greater than or equal to 1 mg/L, 78 (26.3% had tetracycline MICs greater than or equal to 1 mg/L, 13 (4.4% had cefoxitin MICs greater than or equal to 1 mg/L and 43 (14.5% had erythromycin MICs greater than or equal to 1 mg/L. Two isolates (0.7% had high level tetracycline resistance with MICs greater than or equal to 16 mg/L. All N gonorrhoeae isolates were susceptible to ceftriaxone and to spectinomycin.
Aarestrup, Frank Møller; Hasman, Henrik
that Danish bacterial isolates from livestock so far have not or have only to a limited degree developed resistance to antimicrobial compounds commonly used for disinfection. Acquired copper resistance was only found in enterococci. There were large differences in the intrinsic susceptibility of the different......A total of 569 different bacterial isolates (156 Salmonella, 202 E. coli, 43 S. aureus, 38 S. hyicus, 52 E. faecalis, 78 E faecium) were tested for susceptibility to copper sulphate, benzalkonium chloride, hydrogen peroxide and chlorhexidine using MIC determinations. A total of 442 isolates were...... of susceptibilities to the different antimicrobial agents. Large variations were observed in the susceptibility of the different bacterial species to the different compounds. Staphylococci were in general very susceptible to all antimicrobial compounds tested. The Salmonella isolates were in general less susceptible...
Full Text Available Introduction. Streptococcus pneumoniae is one of the leading causes of bacterial meningitis and sepsis. Invasive pneumococcal disease is a significant medical problem worldwide, particularly in children, due to a huge increase of pneumococcal resistance to antibiotics. Objective. The aim of the study was to investigate the antimicrobial susceptibility pattern of invasive pneumococcal isolates, as well as to determine whether decreased S. pneumoniae susceptibility to antibiotics was related to a particular serotype. Methods. Antimicrobial susceptibility to 19 antibiotics was determined in 58 invasive pneumococcal strains that were collected from seven regional centers during the period July 2009 to February 2011 in the National Reference Laboratory for streptococci and pneumococci. Results. The overall nonsusceptibility rate to penicillin was detected in 34% of pneumococcal isolates and to erythromycin in 36%. Higher resistance rates were observed among children than among adults. Penicillin resistance rate was 65% in children versus 22% in adults, while erythromycin nonsusceptibility rate was 47% in children versus 32% in adults. Co-resistance to penicillin and erythromycin was detected in 21% strains, mostly isolated from children. Multiresistance was found in one third of isolates. All strains were susceptible to vancomycin, linezolid, fluoroquinolones, telithromycin and rifampicin, while 23 (40% isolates were susceptible to all tested antibiotics. The most common resistant serotypes were 19F and 14. Conclusion. The study has revealed that penicillin and macrolide resistance among invasive pneumococcal isolates is very high in Serbia. This emphasizes the need for continuous monitoring for invasive pneumococcal disease to document the serotype distribution and antimicrobial susceptibility pattern. [Projekat Ministarstva nauke Republike Srbije, br. 175039: Bakterije rezistentne na antibiotike u Srbiji - fenotipska i genotipska karakterizacija
Limbago, Brandi M
Bacteria in the Staphylococcus intermedius group, including Staphylococcus pseudintermedius, often encode mecA-mediated methicillin resistance. Reliable detection of this phenotype for proper treatment and infection control decisions requires that these coagulase-positive staphylococci are accurately identified and specifically that they are not misidentified as S. aureus. As correct species level bacterial identification becomes more commonplace in clinical laboratories, one can expect to see changes in guidance for antimicrobial susceptibility testing and interpretation. The study by Wu et al. in this issue (M. T. Wu, C.-A. D. Burnham, L. F. Westblade, J. Dien Bard, S. D. Lawhon, M. A. Wallace, T. Stanley, E. Burd, J. Hindler, R. M. Humphries, J Clin Microbiol 54:535-542, 2016, http://dx.doi.org/10.1128/JCM.02864-15) highlights the impact of robust identification of S. intermedius group organisms on the selection of appropriate antimicrobial susceptibility testing methods and interpretation.
Naidoo, S; Perovic, O; Richards, G A; Duse, A G
BACKGROUND. Increasing resistance to some antimicrobial agents among anaerobic bacteria has made susceptibility patterns less predictable. METHOD. This was a prospective study of the susceptibility data of anaerobic organisms isolated from clinical specimens from patients with suspected anaerobic infections from June 2005 until February 2007. Specimens were submitted to the microbiology laboratory at Charlotte Maxeke Johannesburg Academic Hospital, where microscopy, culture and susceptibility testing were performed the using E test® strip minimum inhibitory concentration method. Results were interpreted with reference to Clinical and Laboratory Standards Institute guidelines for amoxicillin-clavulanate, clindamycin, metronidazole, penicillin, ertapenem, cefoxitin, ceftriaxone, chloramphenicol and piperacillin-tazobactam. RESULTS. One hundred and eighty anaerobic isolates were submitted from 165 patients. The most active antimicrobial agents were chloramphenicol (100% susceptible), ertapenem (97.2%), piperacillin-tazobactam (99.4%) and amoxicillin-clavulanic acid (96.7%). Less active were metronidazole (89.4%), cefoxitin (85%), clindamycin (81.7%), ceftriaxone (68.3%) and penicillin (33.3%). CONCLUSION. Susceptibility testing should be performed periodically to identify emerging trends in resistance and to modify empirical treatment of anaerobic infections.
Mateus-Vargas, Rafael H; Atanassova, Viktoria; Reich, Felix; Klein, Günter
The increasing number of antimicrobial resistant Enterobacteriaceae both in veterinary and human medicine, the dissemination of these bacteria in several environments and their possible repercussions on human health is causing concern. Game meat is usually seen as free of antimicrobial resistant bacteria. The objective of this study was to evaluate the current antimicrobial susceptibility status in generic Escherichia coli isolated from packed frozen game meat from a game handling establishment in Germany. A total of 229 E. coli isolates were obtained from cuts of red deer, roe deer and wild boar. The susceptibility to 12 antimicrobial agents was evaluated by a broth microdilution method according to ISO 20776-1:2006. Minimal Inhibitory Concentration (MIC) values were compared to breakpoints and cut-off values published by the EUCAST. Isolates showing MICs above the reference values were further studied for associated resistance determinants and phylogrouping by PCR. Overall, 16 E. coli isolates (7.0%) showed resistance (microbiological or clinical) to at least one antimicrobial agent tested. Clinical resistance was recorded to ampicillin (5/229) and chloramphenicol (4/229), whereas the MIC of 9 isolates exceeded the epidemiological cut-off value for doxycycline. One of the ampicillin-resistant isolates showed resistance to the β-lactam antibiotic derivatives tested, cephalosporines and aztreonam. Three of 9 non-wild-type isolates for doxycycline were positive for tet (B) genes. The ß-lactam-resistant isolate was found to harbour blaCTX-M-1 gene. These data show a low prevalence of resistant E. coli in packed game meat compared to studies on conventional meat. Although isolates obtained in this study may also be originating from the processing environment and not necessarily from animals, based on our results, it is important to monitor the development of antimicrobial resistance in game animals and products in order to identify future threats for the
Maasjost, J; Mühldorfer, K; Cortez de Jäckel S; Hafez, H M
Between 2010 and 2011, 145 Enterococcus isolates (Enterococcus faecalis, n = 127; Enterococcus faecium, n = 18) were collected during routine bacteriologic diagnostics from broilers, layers, and fattening turkeys in Germany showing various clinical signs. The susceptibility to 24 antimicrobial agents was investigated by broth microdilution test to determine minimum inhibitory concentrations (MICs). All E. faecalis isolates (n = 127) were susceptible to the beta-lactam antibiotics ampicillin, amoxicillin-clavulanic acid, and penicillin. Corresponding MIC with 50% inhibition (MIC50) and MIC with 90% inhibition (MIC90) values of these antimicrobial agents were at the lower end of the test range (≤ 4 μg/ml). In addition, no vancomycin-resistant enterococci (VRE) were found. High resistance rates were identified in both Enterococcus species for lincomycin (72%-99%) and tetracycline (67%-82%). Half or more than half of Enterococcus isolates were resistant to gentamicin (54%-72%) and the macrolide antibiotics erythromycin (44%-61%) and tylosin-tartate (44%-56%). Enterococcus faecalis isolated from fattening turkeys showed the highest prevalence of antimicrobial resistance compared to other poultry production systems. Eighty-nine out of 145 Enterococcus isolates were resistant to three or more antimicrobial classes. Again, turkeys stood out with 42 (8 1%) multiresistant isolates. The most-frequent resistance patterns of E. faecalis were gentamicin, lincomycin, and tetracycline in all poultry production systems.
Yuan Zong Hui
Full Text Available Salmonella spp. can indirectly infect humans via transfer from animals and animal-derived food products, and thereby cause potentially fatal diseases. Therefore, gaining an understanding of Salmonella infection in farm animals is increasingly important. The aim of this study was to identify the distribution of serotypes in Salmonella samples isolated from chickens (n = 837, pigs (n = 930, and dairy cows (n = 418 in central China (Henan, Hubei, and Hunan provinces in 2010–2011, and investigate the susceptibility of strains to antimicrobial agents. Salmonella isolates were identified by PCR amplification of the invA gene, serotypes were determined by using a slide agglutination test for O and H antigens, and susceptibility to 24 antimicrobials was tested using the agar dilution method. In total, 248 Salmonella strains were identified: 105, 105, and 38 from chickens, dairy cows, and pigs, respectively. Additionally, 209 strains were identified in unhealthy pigs from the Huazhong Agricultural University veterinary hospital. Among these 457 strains, the dominant serotypes were Typhimurium in serogroup B, IIIb in serogroup C, and Enteritidis in serogroup D. In antimicrobial susceptibility tests, 41.14% of Salmonella spp. were susceptible to all antimicrobial agents, 48.14% were resistant to at least one, and 34.72% were resistant to more than three classes. Strains were highly resistant to sulfamethoxazole-trimethoprim (39.61%, nalidixic acid (39.17%, doxycycline (28.22%, and tetracycline (27.58%. Resistance to cephalosporins and fluoroquinolones ranged from 5.25% to 7.44% and 19.04% to 24.51%, respectively. Among penicillin-resistant and cephalosporin-resistant strains, 25 isolates produced extended-spectrum β-lactamases (ESBLs. The multidrug-resistant and ESBL-producing Salmonella strains identified in healthy animals here will present a challenge for veterinary medicine and farm animal husbandry, and could also pose a threat to public health
Full Text Available Bordetella bronchiseptica causes infections of the respiratory tract in swine and other mammals and is a precursor for secondary infections with Pasteurella multocida. Treatment of B. bronchiseptica infections is conducted primarily with antimicrobial agents. Therefore it is essential to get an overview of the susceptibility status of these bacteria. The aim of this study was to comparatively analyse broth microdilution susceptibility testing according to CLSI recommendations with an incubation time of 16 to 20 hours and a longer incubation time of 24 hours, as recently proposed to obtain more homogenous MICs. Susceptibility testing against a panel of 22 antimicrobial agents and two fixed combinations was performed with 107 porcine isolates from different farms and regions in Germany and 43 isolates obtained from companion animals in Germany and other European countries. Isolates with increased MICs were investigated by PCR assays for the presence of resistance genes. For ampicillin, all 107 porcine isolates were classified as resistant, whereas only a single isolate was resistant to florfenicol. All isolates obtained from companion animals showed elevated MICs for β-lactam antibiotics and demonstrated an overall low susceptibility to cephalosporines. Extension of the incubation time resulted in 1-2 dilution steps higher MIC50 values of porcine isolates for seven antimicrobial agents tested, while isolates from companion animals exhibited twofold higher MIC50/90 values only for tetracycline and cefotaxime. For three antimicrobial agents, lower MIC50 and MIC90 values were detected for both, porcine and companion animal isolates. Among the 150 isolates tested, the resistance genes blaBOR-1 (n = 147, blaOXA-2, (n = 4, strA and strB (n = 17, sul1 (n = 10, sul2 (n = 73, dfrA7 (n = 3 and tet(A (n = 8 were detected and a plasmid localisation was identified for several of the resistance genes.
Background: Antimicrobial resistance in uropathogenic E. coli is of major concern worldwide due to its increasing resistance to several commonly prescribed antibiotics. The aims of this study were to determine the prevalence and to evaluate the presence and antibiogram pattern of uropathogenic E. coli among people in Zakho city, Iraq. Methods: 1120 urine samples were collected from people. Samples were screened for E. coli isolates and their susceptibility to different antibiotics was ana...
Tansarli, Giannoula S.; Athanasiou, Stavros; Falagas, Matthew E
Our objective was to evaluate the antimicrobial susceptibility of Enterobacteriaceae causing urinary tract infections (UTIs) in adults in Africa. The PubMed database was systematically searched to identify relevant studies published after 2000. Google, World Health Organization, and African Field Epidemiology networks were also searched. Twenty-eight studies, accounting for 381,899 urine isolates from 14 African countries, met the inclusion criteria. Escherichia coli, Klebsiella spp., and Pro...
Introduction: Campylobacter spp. are recognized as important agents of human foodborne gastroenteritis. To monitor trends in food safety and public health, antimicrobial susceptibility testing of Campylobacter derived from poultry products and infected patients has become common practice in both r...
Gutiérrez-Martín, César B; del Blanco, Noemí García; Blanco, Mónica; Navas, Jesús; Rodríguez-Ferri, Elías F
A total of 229 Spanish Actinobacillus pleuropneumoniae isolates recovered from diseased pigs with pleuropneumonia from 1997 to 2004 was tested for their susceptibility to 11 antimicrobials in a broth microdilution method. All the isolates were susceptible to florfenicol and most of them to cephalothin; however, a high rate of resistance was observed to tetracycline. A bimodal or multimodal distribution of isolates over the MIC range were observed for penicillins, tetracycline, trimethoprim, sulfisoxazole and nalidixic acid, suggesting the development of acquired resistance. Eight resistance patterns were established, and 21.1% of the isolates were resistant to at least two antimicrobials. In addition, a considerable increase in the resistance to tetracyclines was observed during the last decade in Spain, when compared with other A. pleuropneumoniae strains isolated during 1987-1988 (Gutiérrez, C.B., Píriz, S., Vadillo, S., Rodríguez Ferri, E.F., 1993. In vitro susceptibility of Actinobacillus pleuropneumoniae strains to 42 antimicrobial agents. Am. J. Vet. Res. 54, 546-550); this finding was also observed for gentamicin in minor percentage.
Full Text Available Background: Urinary Tract Infections (UTIs are one of the most common infectious diseases diagnosed all over the world. Meanwhile most episode of UTIs are caused by Escherichia coli (up to 85% and frequently fluoroquinolones are preferred as initial agents for empiric therapy of UTIs. Widespread use of fluoroquinolones has resulted in an increasing incidence of resistance these agents all over the world. The aim of this study was to assess, susceptibility of Escherichia coli strains from UTI patients against common fluoroquinolones. Methods: Antimicrobial susceptibility testing was determined by disk agar diffusion (DAD and Minimal Inhibitory Concentration methods as described by the National Committee for Clinical Laboratory Standards (NCCLS. Results: One hundred sixty four clinical isolates of E. coli were collected by urine cultures from patients with UTI. The extent of resistant to nalidixic acid, ofloxacin, norfloxacin and ciprofloxacin, by disk diffusion method was 49.3%, 44.5%, 41.4% and 40.2%, respectively. Resistance to ciprofloxacin by MIC method was 4.9%. Conclusion: This study represents high level resistant of E. coli isolates from UTI patients. It is because of inappropriate and incorrect administration of antimicrobial agents in blind cases. This problem remarks significance of performing antimicrobial susceptibility testing before empiric antibiotic therapy. To overcome this problem use of unnecessary antibiotics therapy should be limited.
Full Text Available Background Urinary tract infections (UTIs are one of the most common bacterial diseases. The etiological agents and emergence of antimicrobial resistance UTIs vary according to time and geographical region. Objectives The present study aimed to determine the prevalence of etiological agents of UTIs and determine their antimicrobial susceptibility pattern to locally available antibiotics. Patients and Methods This descriptive cross-sectional study was conducted within six months on all patients with clinical symptoms of UTI who referred to Nemazee Teaching hospital, Shiraz, Iran. Clean catch midstream urine samples were collected and cultured on appropriate media in a short time as possible. Conventional bacteriological methods were followed for the isolation and identification of the bacteria. Antimicrobial susceptibility profiles were determined by locally available antibiotics by using disk diffusion method in accordance with CLSI recommendation. Results In this study, from overall 9991 specimens analyzed 848 (8.5% culture had significant bacterial growth. Of the total positive cultures, 500 (59% cases were female. Escherichia coli (50.6% was the predominant gram-negative isolated pathogen followed by Klebsiella spp. and Enterobacter spp., respectively. Enterococcus isolates (11.2% was the most isolated gram-positive cocci. Nitrofurantoin (80.9%, gentamycin (77.9% and amikacin (65.3% had the most in-vitro antibacterial effect on E. coli isolates as the predominant cause of UTIs. Conclusions The results of regional assessments, such as our study, provide not only useful information for prescription of more effective empirical therapy, but also good epidemiological background for comparison of our situation with other regions.
Sun, Wei; Weingarten, Rebecca A.; Xu, Miao; Southall, Noel; Dai, Sheng; Shinn, Paul; Sanderson, Philip E.; Williamson, Peter R.; Frank, Karen M.; Zheng,Wei
Current antimicrobial susceptibility testing has limited screening capability for identifying empirical antibiotic combinations to treat severe bacterial infections with multidrug-resistant (MDR) organisms. We developed a new antimicrobial susceptibility assay using automated ultra-high-throughput screen technology in combination with a simple bacterial growth assay. A rapid screening of 5170 approved drugs and other compounds identified 25 compounds with activities against MDR Klebsiella pne...
Ohnishi, Mamoru; Sawada, Takuo; Hirose, Kazuhiko; Sato, Reiichiro; Hayashimoto, Mizuki; Hata, Eiji; Yonezawa, Chizuko; Kato, Hajime
The presence of metallo-β-lactamase (MBL)-producing and multidrug-resistant Pseudomonas aeruginosa (MDRP) strains among bovine isolates of Gram-negative bacilli, and O-serotypes of bovine Serratia marcescens and P. aeruginosa isolates have been reported rarely. The aims of this study were to (1) elucidate antimicrobial susceptibilities and O-serotypes of P. aeruginosa and S. marcescens isolates from bovine mastitis and the presence of MBL-producers and MDRP strains among them and (2) evaluate their relationships to human isolates. We investigated the MICs of 24 antimicrobials and O-serotypes for 116 P. aeruginosa and 55 S. marcescens isolates in Japan, primarily in 2006. A total of 171 isolates exhibited high antimicrobial susceptibilities with the exception of a partial drug. P. aeruginosa isolates exhibited high susceptibilities of ≥ 95.7% to ciprofloxacin, imipenem, meropenem, piperacillin, ceftazidime, cefepime, cefoperazone/sulbactam, amikacin, tobramycin, and gentamicin; however, they exhibited a susceptibility of only 69.8% to aztreonam. They exhibited substantial resistances to ceftriaxone, enrofloxacin, cefotaxime, and moxalactam. S. marcescens isolates exhibited high susceptibilities of ≥ 90.9% to kanamycin, ceftiofur, sulfamethoxazole-trimethoprim, and the 15 aforementioned drugs, but exhibited resistance to minocycline. Neither MBL-producers nor MDRP strains were detected among the 171 strains. The dominant serotypes of P. aeruginosa isolates were OG, OA, OB, OI, OF, OE, and OK; those of S. marcescens isolates were O6 and O5. Every S. marcescens isolate was pigmented. These findings suggest that bovine P. aeruginosa and S. marcescens isolates differ from human isolates from both antibiogram and phenotypic perspectives, and could help to evaluate differences in bacteriological characteristics between bovine and human isolates.
Qin, Xiaohua; Hu, Fupin; Wu, Shi; Ye, Xinyu; Zhu, Demei; Zhang, Ying; Wang, Minggui
The presence of adhesins is arguably an important determinant of pathogenicity for Uropathogenic Escherichia coli (UPEC). Antimicrobial susceptibilities were tested by agar dilution method, fifteen adhesin genes were detected by polymerase chain reaction, and multilocus sequence typing (MLST) was analyzed in 70 UPEC isolates and 41 commensal E. coli strains. Extended-spectrum β-lactamase (ESBL) was determined with confirmatory test. The prevalence of ESBL-producers in UPEC (53%, 37/70) was higher than the commensal intestinal isolates (7%, 3/41), and 97% (36/37) of the ESBL-producing UPEC harbored bla CTX-M genes. afa was present in 36% (10/28) UPEC isolates from recurrent lower urinary tract infection (UTI), and none in the acute pyelonephritis, acute uncomplicated cystitis or commensal strains (PUPEC isolates, while 5% (2/41) of the commensal strains were papG positive (P = 0.0025), and the prevalence of papG was significantly higher in acute pyelonephritis group (71%) than the other two UTI groups (PUPEC isolates than in the commensal strains. ESBL-producing UPEC showed a lower prevalence of adhesin genes compared with non-ESBL-producing strains. The MLST profiles were different between UPEC and commensal strains, with ST131 (19%, 13/70) and ST10 (20%, 8/41) being the most common MLSTs, respectively. This study demonstrated that several adhesin genes were more prevalent in UPEC isolates than in commensal E. coli, and afa may be associated with recurrent lower UTI whereas papG is more frequently associated with acute pyelonephritis.
Iffat, Wajiha; Shoaib, Muhammad Harris; Muhammad, Iyad Naeem; Rehana; Tasleem, Samiah; Gauhar, Shahnaz
Antibiotic resistance development is an ongoing process associated with irrational antibiotic use. WHO recommends regular surveillance programs for monitoring of antibiotic resistance. The present study is a step in this direction. A total of 124 clinical isolates of Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa were collected from different hospitals in Karachi. In vitro antimicrobial susceptibility studies were carried out by agar dilution method using newer quinolones that included Gatifloxacin and Levofloxacin. It was observed that 50% (n=30) isolates of Staphylococcus aureus were resistant to gatifloxacin. Gatifloxacin was more active against Pseudomonas aeruginosa (n=23) and showing complete susceptibility with MIC 1mg/L except for three very resistant strains that shown resistance at even higher concentrations. Escherichia coli (n=45) has shown 15.5% and Klebsiella pneumoniae (n=26) 34.61% resistance to gatifloxacin. Levofloxacin was more active against Staphylococcus aureus and Escherichia coli showing complete susceptibility at 0.5 mg /L concentration. Pseudomonas aeruginosa and Klebsiella pneumoniae were found to be resistant to Levofloxacin showing 36.36% and 23.08% resistance respectively. The study strongly recommends the adherence to the antibiotic policy and regular susceptibility testing to overcome the problem associated with antimicrobial resistance.
Zalas-Wiecek, Patrycja; Gospodarek, Eugenia; Wróblewska, Joanna
The aim of this study was the evaluation of occurrence and antimicrobial susceptibility of M morganii rods isolated from clinical samples. This study included 201 strains isolated in the Clinical Microbiology Department of Dr. A. Jurasz University Hospital in 2008-2010. Identification to species was carried out on the basis of the results of biochemical reactions included in the tests ID 32E and VITEK2 GN. Antimicrobial susceptibility of M. morganii rods was determined by the disk-diffusion method on Mueller-Hinton II Agar. Strains of M morganii most commonly isolated from skin and soft tissue, and material taken from the urinary tract, mainly from patients of Anesthesiology and Intensive Care Unit, Department of General and Vascular Surgery and Department of General Surgery and Endocrinology. All of M morganii strains isolated during the three years were susceptible to carbapenems. We reported decrease of strains susceptible to piperacillin and chloramphenicol. In 2010 we showed a higher percentage of strains intermediate to tigecycline, compared with 2009. We observed increase in the percentage of strains resistant to cefoperazone with sulbactam and reported decrease in the percentage of strains resistant and intermediate to aminoglycosides. Extended Spectrum Beta-Lactamases were produced by 13 (6,5%) of M morganii strains.
Full Text Available Abstract Background Shigellosis remains considerable public health problem in some developing countries. The nature of Shigellae suggests that they are highly adaptable when placed under selective pressure in a human population. This is demonstrated by variation and fluctuations in serotypes and antimicrobial resistance profile of organisms circulating in differing setting in endemic locations. Antimicrobial resistance in the genus Shigella is a constant threat, with reports of organisms in Asia being resistant to multiple antimicrobials and new generation therapies. Methods Here we compare microbiological, clinical and epidemiological data from patients with shigellosis over three different periods in southern Vietnam spanning14 years. Results Our data demonstrates a shift in dominant infecting species (S. flexneri to S. sonnei and resistance profile of the organisms circulating in southern Vietnam. We find that there was no significant variation in the syndromes associated with either S. sonnei or S. flexneri, yet the clinical features of the disease are more severe in later observations. Conclusions Our findings show a change in clinical presentation of shigellosis in this setting, as the disease may be now more pronounced, this is concurrent with a change in antimicrobial resistance profile. These data highlight the socio-economic development of southern Vietnam and should guide future vaccine development and deployment strategies. Trial Registration Current Controlled Trials ISRCTN55945881
van Hout, Jobke; Heuvelink, Annet; Gonggrijp, Maaike
The objective of the present study was to analyse the in vitro antimicrobial susceptibility of Streptococcus suis isolates from post-mortem samples from pigs in the Netherlands. S. suis isolates originated from diagnostic submissions of pigs sent to the Pathology Department of GD Animal Health, from April 2013 till June 2015. Minimal inhibitory concentrations (MICs) of in total 15 antimicrobials were assessed by broth microdilution following CLSI recommendations. MIC50 and MIC90 values were determined and MICs were interpreted as susceptible, intermediate and resistant using CLSI veterinary breakpoints (when available). Emergence of resistance among S. suis (n=1163) derived from clinical submissions of pigs appeared to be limited. Resistance to ampicillin, ceftiofur, clindamycin, enrofloxacin, florfenicol, penicillin, trimethoprim/sulfamethoxazole and tetracycline was 0.3%, 0.5%, 48.1%, 0.6%, 0.1%, 0.5%, 3.0%, and 78.4%, respectively. Cross-resistance between penicillin and ampicillin appeared to be incomplete. MIC values of erythromycin, clindamycin, neomycin, penicillin and tilmicosin for isolates originating from grower/finisher pigs were significantly more often lower than the MIC values of isolates from suckling/weaned piglets. It has to be kept in mind that these results represent only part of the Dutch pig population and it can be discussed whether this is a representative sample. Interpretation of the MIC results of (clinically relevant) antimicrobials tested for treatment of S. suis infection is strongly hampered by the lack of CLSI-defined veterinary clinical breakpoints that are animal species- and body site-specific. Therefore, and to conduct a clinically reliable monitoring of antimicrobial susceptibility of veterinary pathogens, more species- and organ-specific veterinary breakpoints are urgently needed.
Petersen, A.; Aarestrup, Frank Møller; Hofshagen, Merete
, whereas for Enterococcus spp., two laboratories had less than 90 % concordant results. Susceptibility testing of Salmonella to fluoroquinolones gave rise to almost 0.5% nonconcordant results and susceptibility testing of S. aureus to vancomycin resulted in that 1.8% of the strains were incorrectly......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...... Committee of Clinical Laboratory Standards breakpoints, the percentage of concordant results increased to 98.4% and the performance between laboratories varied between 94.2 and 99.4% concordant results. For E. coli, S., aureus, and Salmonella, all laboratories except one had more than 97% concordant results...
Smith, Stella; Braun, Sascha; Akintimehin, Faith; Fesobi, Toun; Bamidele, Moses; Coker, Akitoye; Monecke, Stefan; Ehricht, Ralf
Microarray-based serogenotyping, antimicrobial susceptibility tests and the detection of relevant resistance genes were performed on isolates of Salmonella spp. from retail meat samples obtained in Lagos, Nigeria. Out of 151 meat samples, 33 Salmonella isolates were obtained. Nine different Salmonella serovars (S. Amoutive, S. Bargny, S. Drac, S. Ealing, S. Urbana, S. Hadar, S. Nyborg, S. Anatum and S. Havana) were identified by microarray-based serogenotyping and confirmed afterwards using classical serotyping. Antibiotic susceptibility tests with 17 antibiotics showed that almost all isolates were fully susceptible to this panel. The results of this study indicated a high prevalence of Salmonella in retail meat, the presence of some previously rather rarely described Serovars in retail meat samples from Lagos, and a need to monitor for Salmonella and their antibiotic resistance determinants. The microarray-based system used herein proved to be perfectly suited as epidemiological tool to replace classical serotyping.
Sanrrangers Sales Silva
Full Text Available ABSTRACT Aspiration of oral bacteria leads to cardiac and respiratory infectious diseases and dentures can act as a reservoir for pathogenic microorganisms. Objective: To determine the occurrence and the in vitro antimicrobial susceptibility of enteric rods and pseudomonads from the denture biofilm of 52 subjects at the Center for Dental Specialties of Sobral/ Ceara, Brazil. Material and Methods: Denture biofilm was collected and samples plated on MacConkey agar. The isolated bacterial colonies were identified using the BBL Crystal enteric/non-fermenter system. Antibiotic bacterial susceptibility was assessed by the disc diffusion method of amoxicillin, amoxicillin/clavulanic acid, doxycycline, tetracycline, tobramycin, imipenem, cefotaxime, and ciprofloxacin. The Minimum Inhibitory Concentration (MIC of cefotaxime, tobramycin, doxycycline, imipenem, and ciprofloxacin was determined for 40 species by E-test. Results: 34 subjects (65.4% harbored enteric rods in their prostheses. Klebsiella pneumoniae (26.5%, Escherichia coli (23.5%, and Enterobacter aerogenes (23.5% were the most prevalent species. All organisms were susceptible to ciprofloxacin and most species were resistant to amoxicillin or amoxicillin/clavulanic acid, demonstrating variable sensitivity patterns to other antimicrobials. However, the MIC showed the emergence of strains with reduced sensitivity to ciprofloxacin (MIC90≥3 μg/ mL and cefotaxime (MIC90≥2 μg/mL. Conclusion: The findings show high prevalence of nosocomial diseases-related bacterial species and low susceptibility to antimicrobial drugs. Therefore, these results imply caution against the indiscriminate use of broad spectrum antibiotics in dental practice.
Silva, Sanrrangers Sales; Ribeiro, Maximilo de Oliveira; Gomes, Francisco Isaac Fernandes; Chaves, Hellíada Vasconcelos; Silva, Antonio Alfredo Rodrigues e; Zanin, Iriana Carla Junqueira; Barbosa, Francisco Cesar Barroso
ABSTRACT Aspiration of oral bacteria leads to cardiac and respiratory infectious diseases and dentures can act as a reservoir for pathogenic microorganisms. Objective: To determine the occurrence and the in vitro antimicrobial susceptibility of enteric rods and pseudomonads from the denture biofilm of 52 subjects at the Center for Dental Specialties of Sobral/ Ceara, Brazil. Material and Methods: Denture biofilm was collected and samples plated on MacConkey agar. The isolated bacterial colonies were identified using the BBL Crystal enteric/non-fermenter system. Antibiotic bacterial susceptibility was assessed by the disc diffusion method of amoxicillin, amoxicillin/clavulanic acid, doxycycline, tetracycline, tobramycin, imipenem, cefotaxime, and ciprofloxacin. The Minimum Inhibitory Concentration (MIC) of cefotaxime, tobramycin, doxycycline, imipenem, and ciprofloxacin was determined for 40 species by E-test. Results: 34 subjects (65.4%) harbored enteric rods in their prostheses. Klebsiella pneumoniae (26.5%), Escherichia coli (23.5%), and Enterobacter aerogenes (23.5%) were the most prevalent species. All organisms were susceptible to ciprofloxacin and most species were resistant to amoxicillin or amoxicillin/clavulanic acid, demonstrating variable sensitivity patterns to other antimicrobials. However, the MIC showed the emergence of strains with reduced sensitivity to ciprofloxacin (MIC90≥3 μg/ mL) and cefotaxime (MIC90≥2 μg/mL). Conclusion: The findings show high prevalence of nosocomial diseases-related bacterial species and low susceptibility to antimicrobial drugs. Therefore, these results imply caution against the indiscriminate use of broad spectrum antibiotics in dental practice. PMID:27812616
Smith, Sinéad M; O'Morain, Colm; McNamara, Deirdre
The gram-negative bacterium Helicobacter pylori (H. pylori) causes chronic gastritis, gastric and duodenal ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Treatment is recommended in all symptomatic patients. The current treatment options for H. pylori infection are outlined in this review in light of the recent challenges in eradication success, largely due to the rapid emergence of antibiotic resistant strains of H. pylori. Antibiotic resistance is a constantly evolving process and numerous studies have shown that the prevalence of H. pylori antibiotic resistance varies significantly from country to country, and even between regions within the same country. In addition, recent data has shown that previous antibiotic use is associated with harbouring antibiotic resistant H. pylori. Local surveillance of antibiotic resistance is warranted to guide clinicians in their choice of therapy. Antimicrobial resistance is assessed by H. pylori culture and antimicrobial susceptibility testing. Recently developed molecular tests offer an attractive alternative to culture and allow for the rapid molecular genetic identification of H. pylori and resistance-associated mutations directly from biopsy samples or bacterial culture material. Accumulating evidence indicates that surveillance of antimicrobial resistance by susceptibility testing is feasible and necessary to inform clinicians in their choice of therapy for management of H. pylori infection.
Full Text Available Uterine microbiology and antimicrobial susceptibility was investigated in 239 mares with fertility problems in a prospective study in Sweden. Uterine swab samples were collected with double guarded swabs and transported overnight before being cultured. The Minimum Inhibitory Concentrations (MIC was determined for a panel of antimicrobials. From 152 of the 239 mares at least one bacterial species was isolated, most frequently E. coli (104 isolates, β-haemolytic streptococci (31 and fungi (16. β-haemolytic streptococci were more frequently (p E. coli (p β-haemolytic streptococcal isolates some resistance was noted for 4 of 11 tested antibiotics, however, all isolates were susceptible to the widely used penicillin G. Among E. coli isolates enrofloxacin was the only of the 10 tested antibiotics for which no resistance was noted. Resistance was most commonly noted to cephalothin (39% of the isolates, streptomycin (22%, trimethoprim/sulphamethoxazole (15% and ampicillin (11%. In conclusion, we show that both E. coli and β-haemolytic streptococci are frequently associated with fertility problems in mares and that antimicrobial resistance is a common feature of E. coli but also recognised for β-haemolytic streptococcal uterine isolates.
Rodriguez-Rivera, Lorraine D; Cummings, Kevin J; Loneragan, Guy H; Rankin, Shelley C; Hanson, Devin L; Leone, William M; Edrington, Thomas S
Dairy cattle are a reservoir of several Salmonella serovars that are leading causes of human salmonellosis. The objectives of this study were to estimate the environmental prevalence of Salmonella on dairy farms in Texas and to characterize the antimicrobial susceptibility of the isolates. Eleven dairy farms throughout Texas were sampled from August through October 2013, using a cross-sectional approach. Samples were collected from four locations within each farm (hospital pen, maternity pen, cow housing area, and calf housing area), and feces were collected from cull cows as available. Environmental and fecal samples were processed for Salmonella, and isolates were tested for susceptibility to 15 antimicrobial agents. Serovar characterization was performed on a subset of these isolates. Salmonella was isolated from 67.0% (236/352) of the environmental samples and 64.2% (43/67) of the cull cow fecal samples. Environmental samples from the maternity pen were significantly more likely to be Salmonella positive than samples from the cow and calf housing areas. Multidrug resistance was evident in 11.9% (27/226) of environmental isolates and 19.5% (8/41) of fecal isolates. Salmonella isolates from the calf housing area and maternity pen were significantly more likely to be multidrug resistant (MDR) than isolates from the cow housing area. The most common serovars found among the MDR isolates were Newport, Muenchen, and Typhimurium. These results help provide a focus for efforts to mitigate the burden of antimicrobial-resistant Salmonella at the preharvest level.
Priyantha, Roshan; Gaunt, Mathew C; Rubin, Joseph E
This study reports antimicrobial susceptibility of Staphylococcus pseudintermedius carried by healthy dogs in Saskatoon, and describes changes in antimicrobial resistance since a 2008 study. One hundred healthy dogs presenting to the wellness service at the Western College of Veterinary Medicine were screened for S. pseudintermedius by culturing rectal and pharyngeal swabs. Staphylococcus pseudintermedius was identified biochemically and antimicrobial minimum inhibitory concentrations were determined by broth microdilution. Methicillin resistance was confirmed by polymerase chain reaction (PCR) and sequencing of the mecA gene. Of 221 S. pseudintermedius isolates from 78 dogs, 7 were methicillin resistant. No resistance to the fluoroquinolones, nitrofurantoin, tigecycline, vancomycin, quinupristin-dalfopristin, linezolid, or daptomycin was identified. Of the 78 positive dogs, isolates resistant to penicillin were found in 78%, to ampicillin in 61% and to tetracycline in 26%; resistance to oxacillin, erythromycin, clindamycin, trimethoprim + sulfamethoxazole, chloramphenicol, and gentamicin was found in < 10% of dogs. Compared to the 2008 study, the frequency of resistance to all drugs increased, and the frequency of colonization with pan-susceptible isolates decreased from 46% to 30%.
Full Text Available Introduction. Campylobacter is one of the leading bacterial causes of food-borne disease. The prevalence of Campylobacter species resistant to antimicrobial agents is increasing. This study is intended to determine prevalence and antimicrobial susceptibility patterns of Campylobacter species among under-five children with diarrhea. Methodology. A cross-sectional study was conducted among 227 under-five children with diarrhea from July to October 2012 at Jimma town. Isolation and identification of Campylobacter species were performed using standard bacteriological techniques. Antimicrobial susceptibility test was performed following standard protocol. Chi-square and Fisher’s exact tests were used for analysis. Results. From 227 under-five children, 16.7% were positive for Campylobacter spp.; isolates, C. jejuni, C. coli, and C. lari, accounted for 71.1%, 21.1%, and 7.9%, respectively. Higher rate of resistance was observed to ampicillin 76.3%, trimethoprim-sulfamethoxazole (68.4%, tetracycline (39.5%, chloramphenicol (31.6%, clindamycin (26.3%, and doxycycline (23.7%. Erythromycin, ciprofloxacin, gentamicin, norfloxacin, and nalidixic acid were effective for more than 80% of the isolates. Multiple drug resistance was observed among 78.9% of all the three spp. Conclusions. Isolation rate of Campylobacter spp. was high. C. lari was reported for the first time at this study area. Higher rate of resistance was observed to the commonly used drugs.
Paterna, A; Tatay-Dualde, J; Amores, J; Prats-van der Ham, M; Sánchez, A; de la Fe, C; Contreras, A; Corrales, J C; Gómez-Martín, Á
The minimum inhibitory concentration (MIC) and minimum mycoplasmacidal concentration (MMC) of 17 antimicrobials against 41 Spanish caprine isolates of Mycoplasma mycoides subsp. capri (Mmc) obtained from different specimens (milk, external auricular canal and semen) were determined using a liquid microdilution method. For half of the isolates, the MIC was also estimated for seven of the antimicrobials using an epsilometric test (ET), in order to compare both methods and assess the validity of ET. Mutations in genes gyrA, gyrB, parC and parE conferring fluoroquinolone resistance, which have been recently described in Mmc, were investigated using PCR. The anatomical origin of the isolate had no effect on its antimicrobial susceptibility. Moxifloxacin and doxycycline had the lowest MIC values. The rest of the fluoroquinolones studied (except norfloxacin), together with tylosin and clindamycin, also had low MIC values, although the MMC obtained for clindamycin was higher than for the other antimicrobials. For all the aminoglycosides, spiramycin and erythromycin, a notable level of resistance was observed. The ET was in close agreement with broth microdilution at low MICs, but not at intermediate or high MICs. The analysis of the genomic sequences revealed the presence of an amino acid substitution in codon 83 of the gene gyrA, which has not been described previously in Mmc.
Pokharel, S; Brooks, J C; Martin, J N; Brashears, M M
As the incidence of multidrug resistance (MDR) Salmonella enterica serotype Typhimurium is increasing, data regarding the antimicrobial interventions and pathogen internalization in marinated meat products are important. This study evaluated the antimicrobial intervention and internalization of Salm. Typhimurium in marinated beef sirloin steaks. Beef bottom sirloin flaps (IMPS #185A; USDA Select) inoculated (10(8) log10 CFU ml(-1) ) with Salm. Typhimurium were sprayed (lactic acid (4%) and buffered vinegar (2%)) prior to vacuum-tumbled marination (0·35% sodium chloride and 0·45% sodium tripolyphosphate) for 30 min. Pathogen presence after antimicrobial spray, vacuum-tumbled marination, and translocation was determined by direct plating on Xylose Lysine Deoxycholate (XLD) agar with tryptic soy agar (TSA) overlay. The data imply varied internalization and antimicrobial susceptibility pattern of Salm. Typhimurium in marinated meat. Lactic acid (4%) spray (P < 0·0001) and buffered vinegar (2%; P < 0·0001) reduced surface populations of Salm. Typhimurium on inoculated beef sirloin flaps prior to vacuum marination. However, lactic acid treated sirloin flaps had greater reductions (~2 log10 CFU cm(-2) ) than buffered vinegar when compared with control prior to vacuum marination. However, the translocation of Salm. Typhimurium following vacuum marination was not influenced (P < 0·333) by the application of a surface organic acid spray prior to marination.
McDermott, Patrick F; Cullen, Patti; Hubert, Susannah K; McDermott, Shawn D; Bartholomew, Mary; Simjee, Shabbir; Wagner, David D
The extent of transfer of antimicrobial resistance from agricultural environments to humans is controversial. To assess the potential hazard posed by streptogramin use in food animals, this study evaluated the effect of virginiamycin exposure on antimicrobial resistance in Enterococcus faecium recovered from treated broilers. Four consecutive broiler feeding trials were conducted using animals raised on common litter. In the first three trials, one group of birds was fed virginiamycin continuously in feed at 20 g/ton, and a second group served as the nontreated control. In the fourth trial, antimicrobial-free feed was given to both groups. Fecal samples were cultured 1 day after chickens hatched and then at 1, 3, 5, and 7 weeks of age. Isolates from each time point were tested for susceptibility to a panel of different antimicrobials. Quinupristin/dalfopristin-resistant E. faecium appeared after 5 weeks of treatment in trial 1 and within 7 days of trials 2 to 4. Following removal of virginiamycin in trial 4, no resistant isolates were detected after 5 weeks. PCR failed to detect vat, vgb, or erm(B) in any of the streptogramin-resistant E. faecium isolates, whereas the msr(C) gene was detected in 97% of resistant isolates. In an experimental setting using broiler chickens, continuous virginiamycin exposure was required to maintain a stable streptogramin-resistant population of E. faecium in the animals. The bases of resistance could not be explained by known genetic determinants.
Katsuda, K; Hoshinoo, K; Ueno, Y; Kohmoto, M; Mikami, O
A total of 378 isolates of Pasteurella multocida from clinically healthy and diseased calves were characterised for their susceptibility to 9 antimicrobial agents and screened by PCR for the presence of antimicrobial resistance genes and 22 genes virulence-associated, including capsule biosynthesis genes. Of the 378 isolates, 102 (27.0%) were resistant to at least one of the 9 tested antimicrobial agents. Resistance to oxytetracycline (21.7%) was the most frequently observed phenotype among the isolates. The tet(H) gene were the primary determinant detected. The resistance rates for thiamphenicol, ampicillin, kanamycin and florfenicol were 13.2%, 5.8%, 9.0% and 0.5%, respectively. Cefazolin, ceftiofur, cefquinome and enrofloxacin were effective antimicrobial agents, with no resistant isolates emerging over the course of the investigation. Most isolates were identified as capsular type A, only 6.3% belonged to capsular type D and no other capsular type was identified. Four of the virulence-associated genes (pfhA, tadD, tbpA and HAS) exhibited associations to the capsular type, and three (pfhA, tbpA and hgbB) were associated with the disease status of the animals. These virulence genes have been considered as epidemiological markers and are hypothesised to have a strong positive association with the outcome of disease in cattle.
White, Brian K.; Mende, Katrin; Weintrob, Amy C.; Beckius, Miriam L.; Zera, Wendy C.; Lu, Dan; Bradley, William; Tribble, David R.; Schnaubelt, Elizabeth R.; Murray, Clinton K.
Data from recent conflicts related to war wounds and obligate anaerobes are limited. We define the epidemiology and antimicrobial susceptibility of obligate anaerobes from Iraq and Afghanistan casualties (6/2009–12/2013), as well as their association with clinical outcomes. Susceptibility against eleven antibiotics (7 classes) was tested. Overall, 59 patients had 119 obligate anaerobes identified (83 were first isolates). Obligate anaerobes were isolated 7–13 days post-injury, primarily from lower extremity wounds (43%), and were largely Bacteroides spp. (42%) and Clostridium spp. (19%). Patients with pelvic wounds were more likely to have Bacteroides spp. and concomitant resistant gram-negative aerobes. Seventy-three percent of isolates were resistant to ≥1 antimicrobials. Bacteroides spp. demonstrated the most resistance (16% of first isolates). Patients with resistant isolates had similar outcomes to those with susceptible strains. Serial recovery of isolates occurred in 15% of patients and was significantly associated with isolation of Bacteroides spp., along with resistant gram-negative aerobes. PMID:26607420
Estepa, Vanesa; Rojo-Bezares, Beatriz; Torres, Carmen; Sáenz, Yolanda
The aim of this study was to analyse the Pseudomonas aeruginosa faecal carriage rate in 98 healthy humans and to perform the phenotypic and genotypic characterization of recovered isolates. The genetic relatedness among the isolates was analysed by pulsed-field gel electrophoresis and multilocus sequence typing that was compared with worldwide epidemic clones. Pseudomonas aeruginosa was isolated from eight healthy individuals (8.2%), and two of them remained colonized after 5 months (in one case by the same clone). All 10 isolates (one/sample) were susceptible to 14 tested antipseudomonal agents and lacked integron structures. Six pulsed-field gel electrophoresis patterns and six sequence types (ST245, ST253, ST254, ST274, ST663 and the new one, ST1059) were identified among them. Four groups of OprD alterations were detected based on mutations and deletions related to PAO1 reference strain in our carbapenem-susceptible strains. This is the first study focused on P. aeruginosa from faecal samples of healthy humans that provides additional insights into the antimicrobial resistance and genetic diversity of P. aeruginosa. Although the isolates were antimicrobial susceptible, most of the sequence types detected were genetically related to Spanish epidemic clones or globally spread sequence types, such as ST274 and ST253.
Fashae, Kayode; Hendriksen, Rene S
Animals including food animals play a significant role in the epidemiology of Salmonella enterica. The control requires identification of sources and institution of targeted interventions. This study investigates the diversity of S. enterica serovars, antimicrobial susceptibility, and occurrence of plasmid-mediated quinolone resistance (PMQR) genes in pigs in Ibadan, Nigeria. Pooled fresh pen floor fecal samples of pigs collected from 31 pig farms were cultured; the Salmonella isolates were serotyped and their antimicrobial susceptibility was determined. PMQR genes were screened by polymerase chain reaction. The 229 Salmonella isolates were made of 50 serovars predominated by rare serovars Salmonella Give (n = 36; 15.7 %), Salmonella Brancaster (n = 17; 7.4 %), Salmonella Colindale (n = 15; 6.6 %), Salmonella Elisaberthville (n = 13; 5.7 %), Salmonella Hillingdon (n = 13; 5.7 %), and Salmonella Kingston (n = 13; 5.7 %). The most widely distributed serovars among the farms were Salmonella Give (six farms) and Salmonella Elisaberthville (six farms). Resistance to chloramphenicol, sulfonamides, nalidixic acid, streptomycin, and tetracycline ranged from 11.6 % (n = 26) to 22.8 % (n = 51). Resistance ciprofloxacin and gentamicin was low (n = 2; 0.9 %). Multiply resistant isolates included Salmonella Kentucky, the most resistant serovar. qnrB19 was found in two isolates of Salmonella Corvallis and one isolate of Salmonella Larochelle, respectively, while qnrS1 was found in two isolates of Salmonella Derby. Other PMQR genes were not detected. Pigs constitute an important source of diverse Salmonella serovars in Ibadan. The isolates were more resistant to old antimicrobials with some multiple resistant. Control measures and regulation of antimicrobials are warranted.
Full Text Available Longitudinal nationwide surveillance data on antimicrobial non-susceptibility and prevalence of extended-spectrum β-lactamases (ESBLs as well as AmpC β-lactamases producers among Escherichia coli from different sources in the community settings are limited. Such data may impact treatment practice. The present study investigated E. coli from outpatients and patients visiting emergency rooms collected by the Taiwan Surveillance of Antimicrobial Resistance (TSAR program. A total of 3481 E. coli isolates were studied, including 2153 (61.9% from urine and 1125 (32.3% from blood samples. These isolates were collected biennially between 2002 and 2012 from a total of 28 hospitals located in different geographic regions of Taiwan. Minimum inhibitory concentrations (MIC were determined using methods recommended by the Clinical Laboratory Standards Institute (CLSI. The prevalence and factors associated with the presence of ESBL and AmpC β-lactamase-producers were determined. Significant increases in non-susceptibility to most β-lactams and ciprofloxacin occurred during the study period. By 2012, non-susceptibility to cefotaxime and ciprofloxacin reached 21.1% and 26.9%, respectively. The prevalence of ESBL- and AmpC- producers also increased from 4.0% and 5.3%, respectively, in 2002-2004, to 10.7% for both in 2010-2012 (P < 0.001. The predominant ESBL and AmpC β-lactamase genes were CTX-M and CMY-types, respectively. Non-susceptibility of urine isolates to nitrofurantoin remained at around 8% and to fosfomycin was low (0.7% but to cefazolin (based on the 2014 CLSI urine criteria increased from 11.5% in 2002-2004 to 23.9% in 2010-2012 (P <0.001. Non-susceptibility of isolates from different specimen types was generally similar, but isolates from elderly patients were significantly more resistant to most antimicrobial agents and associated with the presence of ESBL- and AmpC- β-lactamases. An additional concern is that decreased ciprofloxacin
Girardi, Felipe A; Tonial, Fabiana; Chini, Silvia O; Sobottka, Andréa M; Scheffer-Basso, Simone M; Bertol, Charise D
The phytochemical profile and antimicrobial activity of cultivar (cv.) extracts of Lotus uliginosus (cvs. Trojan and Serrano), L. tenuis (cv. Larrañaga) and L. corniculatus (cv. São Gabriel) were investigated. The phytochemical analysis revealed tannins, coumarins and flavonoids in all extracts, with variations among cultivars, showing genotypic variability. By High Performance Liquid Chromatographic method, the cvs. Larrañaga and São Gabriel showed the highest percentage of catechin and epicatechin, respectively, and presented rutin, which was not detected in the other ones. These genotypes showed antifungal activity but not antibacterial one. The cv. Larrañaga inhibited the mycelia growth of Alternaria sp. and Fusarium graminearum while the cv. São Gabriel was active only against Alternaria sp. The cultivars showed the greatest amounts of secondary metabolites and demonstrated significant activity against filamentous fungi. The results provide a direction for further research about pharmacological use of Lotus spp.
FELIPE A. GIRARDI
Full Text Available The phytochemical profile and antimicrobial activity of cultivar (cv. extracts of Lotus uliginosus (cvs. Trojan and Serrano, L. tenuis (cv. Larrañaga and L. corniculatus (cv. São Gabriel were investigated. The phytochemical analysis revealed tannins, coumarins and flavonoids in all extracts, with variations among cultivars, showing genotypic variability. By High Performance Liquid Chromatographic method, the cvs. Larrañaga and São Gabriel showed the highest percentage of catechin and epicatechin, respectively, and presented rutin, which was not detected in the other ones. These genotypes showed antifungal activity but not antibacterial one. The cv. Larrañaga inhibited the mycelia growth of Alternaria sp. and Fusarium graminearum while the cv. São Gabriel was active only against Alternaria sp. The cultivars showed the greatest amounts of secondary metabolites and demonstrated significant activity against filamentous fungi. The results provide a direction for further research about pharmacological use of Lotus spp.
Poovendran Ponnusamy; Vidhya Natarajan; Murugan Sevanan
Objective:To detect in vitro biofilm formation of uropathogenic Escherichia coli(E. coli)(UPEC) strains isolated from urine specimens and also to determine their antimicrobial susceptibility pattern using 13 commonly used antibiotics.Methods: The present study comprised of166 urine specimens collected from tertiary care hospitals in and around Coimbatore, South India. All the specimens were subjected to gram staining, bacterial culture and theE. coli strains were screened for biofilm formation using Tube Method(TM), Congo Red Agar(CRA) and Tissue Culture Plate method(TCP) respectively. Subsequently, the antimicrobial susceptibility test was performed by Kirby Bauer-disk diffusion method for the biofilm and non-biofilm producingE. colistrains.Results: Of the100 (60.2 %)E. coli strains,72 strains displayed a biofilm positive phenotype under the optimized conditions in the Tube Method and the strains were classified as highly positive(17, 23.6%), moderate positive(19, 26.3 %) and weakly positive(36, 50.0 %), similarly under the optimized conditions on Congo Red agar medium, biofilm positive phenotype strains were classified as highly positive(23, 23 %), moderate positive(37, 37 %)and weakly positive (40, 40%). While inTCP method, the biofilm positive phenotype strains were also classified as highly positive(6, 6 %), moderate positive (80, 80 %)and weakly positive(14, 14 %), it didn’t not correlate well with the tube method for detecting biofilm formation in E. coli. The rates of antibiotic resistance of biofilm producingE. coliwere found to be 100 % for chloramphenicol and amoxyclav (amoxicillin and clavulanic acid),86% for gentamicin and cefotaxime,84% for ceftazidime,83% for cotrimoxazole and piperacillin/tazobactam,75% for tetracycline and70% for amikacin.Conclusions: This study reveals the prevalence and antimicrobial susceptibility pattern of biofilm and non-biofilm producing uropathogenic E. coli strains.
Didier Silveira Castellano-Filho
Full Text Available Group B Streptococcus (GBS is still not routinely screened during pregnancy in Brazil, being prophylaxis and empirical treatment based on identification of risk groups. This study aimed to investigate GBS prevalence in Brazilian pregnant women by culture or polymerase chain reaction (PCR associated to the enrichment culture, and to determine the antimicrobial susceptibility patterns of isolated bacteria, so as to support public health policies and empirical prophylaxis. After an epidemiological survey, vaginal and anorectal specimens were collected from 221 consenting laboring women. Each sample was submitted to enrichment culture and sheep blood agar was used to isolate suggestive GBS. Alternatively, specific PCR was performed from enrichment cultures. Antimicrobial susceptibility patterns were determined for isolated bacteria by agar diffusion method. No risk groups were identified. Considering the culture-based methodology, GBS was detected in 9.5% of the donors. Twenty five bacterial strains were isolated and identified. Through the culture-PCR methodology, GBS was detected in 32.6% specimens. Bacterial resistance was not detected against ampicillin, cephazolin, vancomycin and ciprofloxacin, whereas 22.7% were resistant to erythromycin and 50% were resistant to clindamycin. GBS detection may be improved by the association of PCR and enrichment culture. Considering that colony selection in agar plates may be laboring and technician-dependent, it may not reflect the real prevalence of streptococci. As in Brazil prevention strategies to reduce the GBS associated diseases have not been adopted, prospective studies are needed to anchor public health policies especially considering the regional GBS antimicrobial susceptibility patterns.
Direkel, Şahin; Çopur Çiçek, Ayşegül; Karagöz, Alper; Aydoğan Ejder, Nebahat; Oktay, Efdal; Delialioğlu, Nuran; Özgümüş, Osman Birol; Durmaz, Rıza
Acinetobacter baumannii, an aerobic, non-motile, gram-negative bacterium is an important nosocomial pathogen which shows resistance to the most antibiotics. Carbapenems are the most commonly used antibiotics for the treatment of infections caused by this pathogen. However the emergence of resistance against carbapenems in an increasing rate generates serious problems for antimicrobial therapy. The aims of this study were to detect the antibiotic susceptibility, and the presence of blaOXA resistance genes of clinical A.baumannii isolates and to determine the clonal relationship between these isolates. A total of 79 A.baumannii strains isolated from various clinical specimens (37 respiratory tract samples, 11 wound, 10 blood, 8 catheters, 6 tissue, 5 urine, 2 abscess) of the patients admitted to Mersin University Medical School Hospital between May 2012-January 2013, were included in the study. The isolates were identified by conventional methods and Vitek®2 Compact automated system. Antibiotic susceptibilities of the isolates were determined by Kirby-Bauer disk diffusion method and evaluated according to CLSI criteria. The presence of blaOXA-51, blaOXA-23, blaOXA-24, blaOXA-48 and blaOXA-58 genes were detected by an in-house polymerase chain reaction (PCR), and the clonal relationship between the isolates were identified by pulsed-field gel electroforesis (PFGE) using the ApaI restriction enzyme. In our study, all of the isolates were susceptible to colistin, while the resistance rates against piperacillin-tazobactam, ciprofloxacin, imipenem, meropenem, cefoperazone/sulbactam, trimethoprim-sulfamethoxazole, ceftazidime, levofloxacin, gentamicin, tetracycline, ampicillin-sulbactam, amikacin, netilmicin and tigecycline were 97.5%, 96.2%, 94.9%, 94.9%, 93.6%, 91.1%, 88.6%, 86%, 83.6%, 77.2%, 69.6%, 55.7%, 27.8% and 3.8%, respectively. All the isolates were identified as A.baumannii with the OXA-specific PCR and OXA16S rDNA sequence analysis. All of the isolates (100
Full Text Available From a disease outbreak among Vanaraja fowl, an indigenous Indian Breed reared by backyard system in Jhargram, West Bengal, Salmonella Gallinarum was isolated and characterised. The outbreak occurred among 6-8 day old chicks. A total of 150 birds died in a span of 5 days. Salmonella Gallinarum were identified and confirmed by standard bacteriological methods and presence of invasion ( invA gene was detected by PCR. The isolates were susceptible to 15 common antimicrobials in vitro. Although chemotherapy may be effective, outbreaks of fowl typhoid in backyard poultry warranted precise control policy
Kinnunen, Paivo; McNaughton, Brandon H; Albertson, Theodore; Sinn, Irene; Mofakham, Sima; Elbez, Remy; Newton, Duane W; Hunt, Alan; Kopelman, Raoul
Bacterial antibiotic resistance is one of the major concerns of modern healthcare worldwide, and the development of rapid, growth-based, antimicrobial susceptibility tests is key for addressing it. The cover image shows a self-assembled asynchronous magnetic bead rotation (AMBR) biosensor developed for rapid detection of bacterial growth. Using the biosensors, the minimum inhibitory concentration of a clinical E. coli isolate can be measured within two hours, where currently tests take 6-24 hours. A 16-well prototype is also constructed for simple and robust observation of the self-assembled AMBR biosensors.
Aarestrup, Frank Møller; Agersø, Yvonne; Ahrens, Peter
to ciprofloxacin. Only six (7%) S. aureus isolates and one Staphylococcus saprophyticus were penicillin resistant. Resistance to sulphamethoxazole was observed among 16 (19%) of S. aureus isolates and two coagulase negative staphylococci (CNS). Twenty (24%) of the S. aureus isolates were resistant to erythromycin...... of conventional biochemical testing and 16S rDNA sequencing. The most common species were Staphylococcus aureus (83), Staphylococcus hyicus (11), Staphylococcus xylosus (9) and Staphylococcus cohnii (6). The isolates were susceptible to most antimicrobials tested. A high frequency of S. aureus (30%) was resistant...
Marinésia Aparecida Prado
Full Text Available Cockroaches carry microorganisms to sterilized materials, equipment and non-contaminated food in hospitals and in homes. Hence, they are regarded as major microbial vectors. We isolated and identified microorganisms from living cockroaches captured from a Brazilian health care institution and we determined the antimicrobial susceptibility profile of the isolates. Following collection, cockroaches were immobilized at 4ºC for 10 to 20 minutes, immersed in 0.8% saline solution and then homogenized. Next, the suspension was seeded in culture media: brain and heart agar infusion, MacConkey agar, Naito agar, and they were incubated for up to 48 hours at 37ºC. Sabouraud agar cultures were incubated at ambient temperature. The microbial colonies were analyzed with a stereomicroscope to count and phenotypically identify the colony-forming units (cfu. The discdiffusion method was used to determine the profile of susceptibility to antimicrobials. Among the 103 cockroaches analyzed, fungi were found in 97%, enterobacteria in 74.6% and coagulase-negative staphylococci (CNS in 25.40%. Among the enterobacteria, 96% were resistant to gentamicin, 84% to ampicillin, 75.3% to caphalothin, 66.7% to ampicillin-sulbactam, 50% to aztreonam and 30% to chloramphenicol. Among the CNS, 61% were resistant to oxacillin. We concluded that cockroaches carry organisms associated with nosocomial infections and that are resistant to antimicrobials. This fact contributes to the epidemiological chain, complicating therapeutics, and consequently, medical costs are increased.
Lindsey, Rebecca L; Frye, Jonathan G; Thitaram, Sutawee N; Meinersmann, Richard J; Fedorka-Cray, Paula J; Englen, Mark D
The objective of this study was to examine the distribution of multidrug resistance in Escherichia coli in relation to plasmid replicon types, animal sources, and genotypes. E. coli isolates (n = 35) from seven different animal sources were selected and tested for susceptibility to 15 antimicrobials; pulsed-field gel electrophoresis was used to determine genetic relationships among the E. coli isolates. Plasmid types based on their incompatibility (Inc) replicon types were determined, and linkage disequilibrium analysis was performed for antimicrobial resistance profiles, replicon types, and animal source. A high degree of genotypic diversity was observed: 34 different pulsed-field gel electrophoresis types among the 35 isolates examined. Twelve different plasmid Inc types were detected, and all isolates carried at least one replicon type. IncF (n = 25; 71.4%) and IncFIB (n = 19; 54.3%) were the most common replicon types identified. Chloramphenicol resistance was significantly linked with four Inc types (A/C, FIIA, F, and Y), and amoxicillin/clavulanic acid was linked with three Inc types (B/O, P and Y). Resistance to any other antimicrobial was linked to two or fewer replicon types. The isolate source was linked with resistance to seven antimicrobials and IncI1. We conclude that commensal E. coli from animal sources are highly variable genotypically and are reservoirs of a diverse array of plasmids carrying antimicrobial resistance.
Background Though important in the context of food microbiology and as potential pathogens in immuno-compromised humans, bacterial isolates belonging to the genus Pediococcus are best known for their association with contamination of ethanol fermentation processes (beer, wine, or fuel ethanol). Use of antimicrobial compounds (e.g., hop-compounds, Penicillin) by some industries to combat Pediococcus contaminants is long-standing, yet knowledge about the resistance of pediococci to antimicrobial agents is minimal. Here we examined Pediococcus isolates to determine whether antibiotic resistance is associated with resistance to hops, presence of genes known to correlate with beer spoilage, or with ability to grow in beer. Results Lactic acid bacteria susceptibility test broth medium (LSM) used in combination with commercially available GPN3F antimicrobial susceptibility plates was an effective method for assessing antimicrobial susceptibility of Pediococcus isolates. We report the finding of Vancomycin-susceptible Pediococcus isolates from four species. Interestingly, we found that hop-resistant, beer-spoilage, and beer-spoilage gene-harbouring isolates had a tendency to be more susceptible, rather than more resistant, to antimicrobial compounds. Conclusion Our findings indicate that the mechanisms involved in conferring hop-resistance or ability to spoil beer by Pediococcus isolates are not associated with resistance to antibiotics commonly used for treatment of human infections. Also, Vancomycin-resistance was found to be isolate-specific and not intrinsic to the genus as previously believed. PMID:19735560
Full Text Available Abstract Background Though important in the context of food microbiology and as potential pathogens in immuno-compromised humans, bacterial isolates belonging to the genus Pediococcus are best known for their association with contamination of ethanol fermentation processes (beer, wine, or fuel ethanol. Use of antimicrobial compounds (e.g., hop-compounds, Penicillin by some industries to combat Pediococcus contaminants is long-standing, yet knowledge about the resistance of pediococci to antimicrobial agents is minimal. Here we examined Pediococcus isolates to determine whether antibiotic resistance is associated with resistance to hops, presence of genes known to correlate with beer spoilage, or with ability to grow in beer. Results Lactic acid bacteria susceptibility test broth medium (LSM used in combination with commercially available GPN3F antimicrobial susceptibility plates was an effective method for assessing antimicrobial susceptibility of Pediococcus isolates. We report the finding of Vancomycin-susceptible Pediococcus isolates from four species. Interestingly, we found that hop-resistant, beer-spoilage, and beer-spoilage gene-harbouring isolates had a tendency to be more susceptible, rather than more resistant, to antimicrobial compounds. Conclusion Our findings indicate that the mechanisms involved in conferring hop-resistance or ability to spoil beer by Pediococcus isolates are not associated with resistance to antibiotics commonly used for treatment of human infections. Also, Vancomycin-resistance was found to be isolate-specific and not intrinsic to the genus as previously believed.
Lidan, Chen; Linhai, Li; Yang, Liao; Zhaohui, Sun; Xiaoyan, Huang; Yuling, Shi
This study aimed to investigate the molecular characteristics and antimicrobial susceptibility of Clostridium difficile clinical isolates in Guangzhou, China. One hundred twenty isolates were collected from Guangzhou General Hospital at the Guangzhou Military Command in China from March 2014 to April 2015, and 9 isolates were identified as tcdA-negative/tcdB-positive (A(-)B(+)) strains. Results showed that all of the strains were confirmed to be ST37 and 0 single nucleotide variants (SNVs) were found in the PaLoc region, and >60 SNVs were identified throughout the whole genome sequence. The results show the diversity of the antibiotic and gene mutations present in these strains. All of the A(-)B(+) isolates were highly resistant to clindamycin and erythromycin; showed an average sensitivity to fluoroquinolones; and maintained a high susceptibility to metronidazole, vancomycin, and tigecycline.
Rodrigo Otávio Silveira Silva
Full Text Available The aim of this study was to isolate, genotype and evaluate the antimicrobial susceptibility of Clostridium perfringens found in species Tinamidae, Cracidae and Ramphastidae in Brazil. C. perfringens was isolated in 13 (5% out of 260 swab samples and five (8.3% out of 60 stool samples. All strains were classified as C. perfringens type A, and nine (50% were positive for the beta-2 toxin-encoding gene. No strains were positive for the necrotic enteritis toxin B-like (NetB-encoding gene. All isolates were susceptible to penicillin, metronidazole and vancomycin, whereas four (22.2%, five (27.8% and 13 (72.2% strains were considered resistant to erythromycin, oxytetracycline and lincomycin, respectively.
Guérin-Faublée, V; Flandrois, J P; Broye, E; Tupin, F; Richard, Y
Actinomyces pyogenes induces suppurative diseases in ruminants and many other animal species. Most of the earlier antimicrobial susceptibility data has been obtained by disk diffusion techniques. Minimal inhibitory concentrations (MIC) of 22 antibiotics for 103 strains of A pyogenes of animal origin were determined by agar dilution test (Mueller-Hinton agar supplemented with 5% sheep blood). All the strains were susceptible to penicillin G, amoxicillin, methicillin, cephalothin, cefoperazone, pristinamycin, kanamycin, gentamicin, spectinomycin, chloramphenicol, vancomycin, novobiocin and rifampin. Fifty-nine percent were resistant to streptomycin, 67% to tetracycline, doxycycline and minocycline, 12% to erythromycin, spiramycin and lincomycin. Most of the strains resistant to macrolides and lincosamides exhibited a constitutive MLS(B)-like phenotype. In the cultural conditions used, it was not possible to determine accurate MIC of fucidic acid and pefloxacin.
Rubin, Joseph E; Ball, Katherine R; Chirino-Trejo, Manuel
This study characterized the antimicrobial susceptibility of 221 Staphylococcus aureus isolated from various species, and 60 canine Staphylococcus pseudintermedius isolated from 1986 through 2000 at the Western College of Veterinary Medicine (WCVM). Resistance of S. aureus was most common to penicillin (31%) and tetracycline (14%); resistance of S. pseudintermedius to penicillin was present in 8% and to tetracycline in 34% of isolates. Resistance to trimethoprim/sulfamethoxazole was only seen among S. pseudintermedius, and there was no resistance to amoxicillin/clavulanate, ampicillin/sulbactam, cephalothin, amikacin, gentamicin, enrofloxacin, chloramphenicol, or rifampin among any isolate. Inducible clindamycin resistance was found in both S. aureus and S. pseudintermedius, highlighting the need for careful interpretation of culture and susceptibility test results. There were significant differences in the minimum inhibitory concentrations of penicillin, ciprofloxacin, enrofloxacin, clindamycin, erythromycin, chloramphenicol, and tetracycline between avian, bovine, equine, and porcine isolates.
Zankari, Ea; Hasman, Henrik; Kaas, Rolf Sommer;
genes and MLST types (where MLST stands for multilocus sequence typing). ResFinder results were compared with phenotypic antimicrobial susceptibility testing results using EUCAST epidemiological cut-off values and MLST types. Results: A total of 3051 different phenotypic tests were performed; 482 led......-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...... on 200 isolates originating from Danish pigs, covering four bacterial species. Genomic DNA was purified from all isolates and sequenced as paired-end reads on the Illumina platform. The web servers ResFinder and MLST (www.genomicepidemiology.org) were used to identify acquired antimicrobial resistance...
Vay, Carlos; Cittadini, Roxana; Barberis, Claudia; Hernán Rodríguez, Carlos; Perez Martínez, Herminia; Genero, Fabiana; Famiglietti, Angela
Non-enterococcal Gram-positive bacteria that are intrinsically vancomycin-resistant have been infrequently isolated in association with serious infections. However, well-documented infections have lately been reported with increasing frequency. Because these organisms may be pathogens, we tested the MICs of 19 antimicrobial agents by the agar dilution method for predicting susceptibility. The activity of these antimicrobial agents was assessed against 28 strains (Lactobacillus rhamnosus, 6; Lactobacillus acidophilus, 1; Lactobacillus casei, 1; Lactobacillus fermentum, 2; Lactobacillus brevis, 1; Lactobacillus plantarum, 1; Weissella confusa, 2; Leuconostoc mesenteroides, 7; Leuconostoc lactis, 4; Pediococcus acidilactici, 2; Pediococcus pentosaceus, 1), isolated from clinical specimens in an Argentinian university hospital from 1997 to 2003. The MICs of penicillin for 67% of the Lactobacillus strains and 100% of the Leuconostoc spp. and Pediococcus spp. strains tested were in the 0.25-2 microg/mL range. Erythromycin was the most active antimicrobial overall. Multiresistance was observed in 2 strains (Lactobacillus rhamnosus, 1; Lactobacillus plantarum, 1).
Aarestrup, Frank Møller; Jensen, Lars Bogø
From 1996 to 2001 a total of 467 Staphylococcus hyicus isolates from exudative epidermitis (EE) in pigs in Denmark were examined for susceptibility to 13 different antimicrobial agents. The presence of selected genes encoding macrolide (erm(A), erm(B) and erm(C)), penicillin (blaZ), streptogramin...
Full Text Available Abstract Background Bloodstream infections are associated with significant patient morbidity and mortality. Antimicrobial susceptibility patterns should guide the choice of empiric antimicrobial regimens for patients with bacteremia. Methods From January to December of 2002, 82,569 bacterial blood culture isolates were reported to The Surveillance Network (TSN Database-USA by 268 laboratories. Susceptibility to relevant antibiotic compounds was analyzed using National Committee for Clinical Laboratory Standards guidelines. Results Coagulase-negative staphylococci (42.0%, Staphylococcus aureus (16.5%, Enterococcus faecalis (8.3%, Escherichia coli (7.2%, Klebsiella pneumoniae (3.6%, and Enterococcus faecium (3.5% were the most frequently isolated bacteria from blood cultures, collectively accounting for >80% of isolates. In vitro susceptibility to expanded-spectrum β-lactams such as ceftriaxone were high for oxacillin-susceptible coagulase-negative staphylococci (98.7%, oxacillin-susceptible S. aureus (99.8%, E. coli (97.3%, K. pneumoniae (93.3%, and Streptococcus pneumoniae (97.2%. Susceptibilities to fluoroquinolones were variable for K. pneumoniae (90.3–91.4%, E. coli (86.0–86.7%, oxacillin-susceptible S. aureus (84.0–89.4%, oxacillin-susceptible coagulase-negative staphylococci (72.7–82.7%, E. faecalis (52.1%, and E. faecium (11.3%. Combinations of antimicrobials are often prescribed as empiric therapy for bacteremia. Susceptibilities of all blood culture isolates to one or both agents in combinations of ceftriaxone, ceftazdime, cefepime, piperacillin-tazobactam or ciprofloxacin plus gentamicin were consistent (range, 74.8–76.3% but lower than similar β-lactam or ciprofloxacin combinations with vancomycin (range, 93.5–96.6%. Conclusion Ongoing surveillance for antimicrobial susceptibility remains essential, and will enhance efforts to identify resistance and attempt to limit its spread.
GUO Peng; WANG Na; LIU Yong-jie; LU Cheng-ping
Aeromonas hydrophila isolates from clinical cases (n=43) were tested against 8 antimicrobial agents and typed by outer membrane protein (OMP) pattern by using sodium dodecyl sulfate gel electrophoresis. All isolates were resistant to ampicillin (MICs, 16 mg mL-1) and sulfamonomethoxine (MICs, 64 mg mL-1), but susceptible to norlfoxacin (MICs, 0.5 mg mL-1). There was a high incidence of resistance to erythromycin (90.70%) and tylosin (93.02%), while a low incidences of resistance to ciprofloxacin (2.33%), enrofloxacin (2.33%) and florfenicol (4.65%). Six different outer membrane protein patterns were found among 34 isolates by analyzing proteins in the range of 22 to 50 kDa, other than 9 isolates with their respective proifles. The strains with the similar OMP proifles had similar resistances. Compared with the other strains from the same OMP patterns, NB-1, A.Pun and MR-1 had lacked the proteins in the range of 30 to 45 kDa and their resistance to lforfenicol substantially increased. It is speculated that the outer membrane protein changes might correlate with decreased susceptibility to lforfenicol in the three strains. Some strains which showed completely identical OMP types had a little difference in their resistance to lfuoroquinolones, indicating that there might be other factors that were involved in the antimicrobial resistance of A. hydrophila.
Castelo-Branco, Débora de Souza Collares Maia; Guedes, Glaucia Morgana de Melo; Brilhante, Raimunda Sâmia Nogueira; Rocha, Marcos Fábio Gadelha; Sidrim, José Júlio Costa; Moreira, José Luciano Bezerra; Cordeiro, Rossana de Aguiar; Sales, Jamille Alencar; Riello, Giovanna Barbosa; de Alencar, Lucas Pereira; Paiva, Manoel de Araújo Neto; Vasconcelos, David Caldas; de Menezes, Isis Sousa Bezerra; de Ponte, Yago Brito; Sampaio, Célia Maria de Souza; Monteiro, André Jalles; Bandeira, Tereza de Jesus Pinheiro Gomes
The aims of the present study were to isolate and identify clinical and environmental strains of Aeromonas spp. by means of biochemical tests and the automated method VITEK 2 and to investigate the presence of the virulence genes cytotoxic enterotoxin (act), hemolysin (asa-1), and type III secretion system (ascV), and also the in vitro antimicrobial susceptibility of the strains. From the clinical isolates, 19 Aeromonas hydrophila, 3 Aeromonas veronii bv. sobria, and 1 Aeromonas caviae were identified, while from the environmental strains, 11 A. hydrophila, 22 A. veronii bv. sobria, 1 A. veronii bv. veronii, and 1 A. caviae were recovered. The gene act was detected in 69.5% of clinical isolates, asa-1 in 8.6%, and ascV in 34.7%. In the environmental strains, the detection rates were 51.4%, 45.7%, and 54.2% for the genes act, asa-1, and ascV, respectively. Resistance to amoxicillin-clavulanate and piperacillin-tazobactam was observed in 15 and 3 clinical strains, respectively, and resistance to ceftazidime, meropenem, imipenem, ciprofloxacin, and trimethoprim-sulfamethoxazole was observed in 1 strain for each drug. Resistance to amoxicillin-clavulanate and piperacillin-tazobactam was detected in 17 and 1 environmental strain, respectively. Higher resistance percentages were observed in clinical strains, but environmental strains also showed this phenomenon and presented a higher detection rate of virulence genes. Thus, it is important to monitor the antimicrobial susceptibility and pathogenic potential of the environmental isolates.
Full Text Available "nBackground: Urinary tract infection (UTI is considered as the most common bacterial infectious disease seen among the pediatric patients. The aim of this study was to investigate the prevalence and antimicrobial susceptibility of bacterial uropathogens isolated from the pediatric patients with urinary tract infections."nMethods: This descriptive study was conducted in Children Medial Center, Tehran, Iran from March 2006 to Feb 2007. Clean-catch midstream urine specimens were obtained from the patients and cultured on the appropriate bacteriological media. Bacterial isolates were identified by standard biochemical and serological tests. Antimicrobial susceptibility testing was performed according to CLSI guidelines."nResults: From 14199 urine specimens, 16.2% had positive results for bacterial cultures. Nine hundred twenty one strains were identified as Escherichia coli; 412 as Klebsiella spp., 285 as Coagulase negative Staphylocococci, 202 as Enterococcus spp., 158 as Pseudomonas spp., and 83 as Staphylococcus aureus. E. coli isolates showed high resistance to carbenicillin (68%, ampicillin (96%, trimethoprim-sulfomethoxazol (70% and kanamycin (65%. More than 30% of isolates of Klebsiella spp., Pseudomonas spp. and Enterobacter spp. have shown high degree of resistance to commonly used antibiotics."nConclusion: Our findings reinforce the need for ongoing investigation to show trends in antibiotic resistance, which can help to prescribing of antibiotics in clinics.
Garedew, Legesse; Hagos, Zenabu; Addis, Zelalem; Tesfaye, Reta; Zegeye, Bidir
Background Salmonella has been recognized as a major cause of food borne illness associated with meat products worldwide. The wide spread of antimicrobial-resistant Salmonella has been a serious global human and animal health problem. The aims of this study were to estimate the prevalence and antimicrobial susceptibility pattern of Salmonella isolates from butcher shops of Gondar town, Ethiopia. Methods A cross-sectional study was conducted from February to June, 2013 in Gondar town. After re...
Palaniappan, Kavitha; Holley, Richard A
Plant-derived antibacterial compounds may be of value as a novel means for controlling antibiotic resistant zoonotic pathogens which contaminate food animals and their products. Individual activity of natural antimicrobials (eugenol, thymol, carvacrol, cinnamaldehyde, allyl isothiocyanate (AIT)) and activity when paired with an antibiotic was studied using broth microdilution and checkerboard methods. In the latter assays, fractional inhibitory concentration (FIC) values were calculated to characterize interactions between the inhibitors. Bacteria tested were chosen because of their resistance to at least one antibiotic which had a known genetic basis. Substantial susceptibility of these bacteria toward the natural antimicrobials and a considerable reduction in the minimum inhibitory concentrations (MIC's) of the antibiotics were noted when paired combinations of antimicrobial and antibiotic were used. In the interaction study, thymol and carvacrol were found to be highly effective in reducing the resistance of Salmonella Typhimurium SGI 1 (tet A) to ampicillin, tetracycline, penicillin, bacitracin, erythromycin and novobiocin (FIC<0.4) and resistance of Streptococcus pyogenes ermB to erythromycin (FIC<0.5). With Escherichia coli N00 666, thymol and cinnamaldehyde were found to have a similar effect (FIC<0.4) in reducing the MIC's of ampicillin, tetracycline, penicillin, erythromycin and novobiocin. Carvacrol, thymol (FIC<0.3) and cinnamaldehyde (FIC<0.4) were effective against Staphylococcus aureus blaZ and in reducing the MIC's of ampicillin, penicillin and bacitracin. Allyl isothiocyanate (AIT) was effective in reducing the MIC of erythromycin (FIC<0.3) when tested against S. pyogenes. Fewer combinations were found to be synergistic when the decrease in viable population (log DP) was calculated. Together, fractional inhibitory concentrations < or = 0.5 and log DP<-1 indicated synergistic action between four natural antimicrobials and as many as three antibiotics
Couto, Natacha; Belas, Adriana; Couto, Isabel; Perreten, Vincent; Pomba, Constança
Forty methicillin-resistant and -susceptible Staphylococcus pseudintermedius (MRSP and MSSP, respectively) from colonization and infection in dogs and cats were characterized for clonality, antimicrobial, and biocide susceptibility. MSSP were genetically more diverse than MRSP by multi-locus sequence typing and pulsed-field gel electrophoresis. Three different spa types (t06, t02, t05) and two SCCmec types (II-III and V) were detected in the MRSP isolates. All MRSP and two MSSP strains were multidrug-resistant. Several antibiotic resistance genes (mecA, blaZ, tet(M), tet(K), aac(6')-Ie-aph(2')-Ia, aph(3')-III, ant(6)-Ia, sat4, erm(B), lnu(A), dfr(G), and catp(C221)) were identified by microarray and double mutations in the gyrA and grlA genes and a single mutation in the rpoB gene were detected by sequence analysis. No differences were detected between MSSP and MRSP in the chlorhexidine acetate (CHA) minimum inhibitory concentrations (MICs). However, two MSSP had elevated MIC to triclosan (TCL) and one to benzalkonium chloride and ethidium bromide. One MSSP isolate harboured a qacA gene, while in another a qacB gene was detected. None of the isolates harboured the sh-fabI gene. Three of the biocide products studied had high bactericidal activity (Otodine(®), Clorexyderm Spot Gel(®), Dermocanis Piocure-M(®)), while Skingel(®) failed to achieve a five log reduction in the bacterial counting. S. pseudintermedius have become a serious therapeutic challenge in particular if methicillin- resistance and/or multidrug-resistance are involved. Biocides, like CHA and TCL, seem to be clinically effective and safe topical therapeutic options.
Moodley, Arshnee; Damborg, Peter; Nielsen, Søren Saxmose
Staphylococcus pseudintermedius is a commensal and a common opportunistic pathogen causing mainly infections of the integumentary system in dogs. The recent emergence of multidrug-resistant S. pseudintermedius isolates, in particular methicillin-resistant strains (MRSP) is a threat to small animal health and highlights the need for antimicrobial resistance surveillance to detect trends and potentially perform timeous interventions. We systematically reviewed 202 published articles to investigate temporal changes in antimicrobial resistance in clinical and commensal S. pseudintermedius isolated from dogs in 27 countries between 1980 and 2013. Resistance to the most common antimicrobials tested for in published studies and important for the treatment of staphylococcal infections in dogs were assessed separately for methicillin resistant (MRSP) and methicillin susceptible (MSSP) isolates. Stratified by MSSP and MRSP, no significant increases in antimicrobial resistance were observed over time, except for the penicillinase-labile penicillins (penicillin and ampicillin) among MSSP. However, in recent years, a few studies have reported higher-level of resistance to amikacin, gentamicin 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 are collected and presented in a more harmonized way to allow more precise comparison of susceptibility patterns between studies. One way to accomplish this would be through systematic surveillance either at the country-level or at a larger scale across countries e.g. EU level.
Ana C Gales
Full Text Available The antimicrobial susceptibility of 176 unusual non-fermentative gram-negative bacilli (NF-GNB collected from Latin America region through the SENTRY Program between 1997 and 2002 was evaluated by broth microdilution according to the National Committee for Clinical Laboratory Standards (NCCLS recommendations. Nearly 74% of the NF-BGN belonged to the following genera/species: Burkholderia spp. (83, Achromobacter spp. (25, Ralstonia pickettii (16, Alcaligenes spp. (12, and Cryseobacterium spp. (12. Generally, trimethoprim/sulfamethoxazole (MIC50, 16 µg/ml; 18.8% susceptible and meropenem (MIC50, 8 µg/ml; 50% susceptible against Ralstonia pickettii. Since selection of the most appropriate antimicrobial agents for testing and reporting has not been established by the NCCLS for many of NF-GNB species, results from large multicenter studies may help to guide the best empiric therapy.
Antimicrobial susceptibility of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis isolated from community-acquired respiratory tract infections in China: Results from the CARTIPS Antimicrobial Surveillance Program.
Zhang, Yawei; Zhang, Feifei; Wang, Hui; Zhao, Chunjiang; Wang, Zhanwei; Cao, Bin; Du, Yan; Feng, Xianju; Hu, Yunjian; Hu, Bijie; Ji, Ping; Liu, Zhiyong; Liu, Yong; Liao, Wanzhen; Lu, Juan; Sun, Hongli; Wang, Zhongxin; Xu, Xiuli; Xu, Xuesong; Yang, Qing; Yu, Yunsong; Zhang, Rong; Zhuo, Chao
This study investigated the antimicrobial susceptibilities of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis isolates causing adult community-acquired respiratory tract infections (CARTIs) in China. A multicentre resistance surveillance study (CARTIPS) investigating 1046 clinical isolates from 19 hospitals in China was conducted from 2013 to 2014. Based on the minimum inhibitory concentration (MIC) breakpoints of oral penicillin, the percentages of penicillin-resistant, penicillin-intermediate and penicillin-susceptible S. pneumoniae were 44.1%, 13.7%, and 42.2%, respectively. The rates of penicillin-non-susceptible S. pneumoniae ranged from 27.9% to 72.2% in different cities, with the highest rate in Nanchang. Macrolides, including azithromycin, clarithromycin and erythromycin, showed the lowest activities against S. pneumoniae isolates, with resistance rates of 90.5%, 92.2% and 93.0%, respectively. However, 98% of these strains were susceptible to levofloxacin and moxifloxacin. For H. influenzae isolates, most of the antimicrobials agents exhibited good activities. However, ampicillin and trimethoprim/sulfamethoxazole showed relatively lower activity against H. influenzae, with resistance rates of 35.0% and 54.4%, respectively. β-lactamase production rates amongst H. influenzae and M. catarrhalis were 31.0% and 87.1%, respectively. In addition, a total of 15 β-lactamase-negative ampicillin-resistant (BLNAR) strains identified in this study were resistant to ampicillin, amoxicillin/clavulanic acid, cefaclor and cefuroxime. Most of the antimicrobial agents showed excellent activity against M. catarrhalis, with susceptibility rates of >90%. The results from the current study confirmed the regional variations in antimicrobial susceptibility of major CARTI pathogens and provided some choices for the treatment of these organisms. Continuous national surveillance of the epidemiology of CARTIs is strongly warranted in China.
Gamboa, Fredy; García, Dabeiba-Adriana; Acosta, Adriana; Mizrahi, Deborah; Paz, Andreína; Martínez, Diana; Arévalo, Azucena; Aristizabal, Fabio; Abba, Martín
therapies in which antimicrobial susceptibility profile reports should be considered as part of periodontal treatment.
Contaminação bacteriana em concentrados plaquetários: identificação, perfil de sensibilidade aos antimicrobianos e sepse associada à transfusão Bacterial contamination on platelet concentrates: identification, antimicrobial susceptibility profile and transfusion-related sepsis
Full Text Available INTRODUÇÃO: Devido à sepse bacteriana associada à transfusão de concentrados plaquetários (CPs ter sérias consequências clínicas para os pacientes, alguns procedimentos têm sido incorporados na preparação e no controle de qualidade dos componentes sanguíneos para reduzir o risco da contaminação bacteriana. Este artigo descreve a prevalência da contaminação bacteriana dos CPs que foram transfundidos, o espectro bacteriano detectado com seu perfil de sensibilidade aos antimicrobianos e as reações transfusionais nos receptores. MÉTODOS: Um total de 292 CPs (278 randômicos e 14 por aférese, proveniente do Hemocentro do Estado do Rio Grande do Sul (HEMORGS de Santa Maria foi testado. As quantidades de 100μL e 200μL foram coletadas da porção tubular da bolsa de plaquetas e semeadas utilizando dois tipos de metodologias. RESULTADOS: Em cinco unidades(1,7%; 5/292 foram isoladas bactérias pela metodologia qualitativa e apenas uma pela quantitativa. Staphylococcus epidermidis foi o microrganismo identificado em todas as amostras. Dois pacientes apresentaram sepse associada à transfusão com desfecho fatal. CONCLUSÕES: A contaminação bacteriana pelas transfusões de CPs constitui-se num importante problema de saúde pública devido a sua associação com altas taxas de morbidade e mortalidade. Neste estudo, somente microrganismos gram-positivos foram isolados sendo que nenhuma amostra obtida por aférese apresentou contaminação.INTRODUCTION: Bacterial sepsis associated with the transfusion of platelet concentrates (PCs results in serious clinical implications for patients. Given these implications, certain procedures have been integrated into the preparation and quality control of blood components to reduce the risk of bacterial contamination. This article describes the prevalence of bacterial contamination on transfused PCs, the bacterial spectrum detected and their antimicrobial susceptibility profile and transfusion
Pedersen, K; Wegener, H C
A total of 60 Staphylococcus intermedius strains from dogs were investigated by their sensitivity to various antibiotics (50 strains) and by their rRNA gene restriction patterns (ribotyping) (60 strains). Fifteen isolates were from healthy dogs, 9 with otitis externa, and 36 with pyoderma, including 10 strains from a previous study. Sixty per cent of the 50 strains tested for antibiotic susceptibility demonstrated resistance to penicillin, 24% to spiramycin, 20% to tetracycline, 16% to chloramphenicol, and 2% to fucidic acid. All isolates were susceptible to amoxycillin with clavulanic acid, enrofloxacin, and sulphonamides with trimethoprim. There were no significant differences in antimicrobial susceptibility patterns observed among isolates from pyoderma, otitis externa or healthy dogs. Among the 60 strains studied by ribotyping, 10 different ribotypes were identified: 6 different ribotypes among isolates from otitis externa, 8 among isolates from pyoderma, and 5 among isolates from healthy dogs. One ribotype (profile C) was dominant among the isolates from healthy dogs while another ribotype (profile A) was dominant among strains from dogs suffering from pyoderma. This profile was not demonstrated in any of the strains from healthy dogs. From 5 different dogs suffering from pyoderma, 2 different clones were demonstrated based on their plasmid profile and antibiogram. In these dogs 1 of the clones always belonged to ribotype A. The results concerning strains of S. intermedius isolated from furunculosis suggest the existence of distinct subpopulations with different pathogenicity to dogs.
Mazhar Salim Al Zoubi
Full Text Available Background and Objectives: The global spread of methicillin resistant Staphylococcus aureus (MRSA constitutes one of the most serious contemporary challenges to the treatment of hospital-acquired infections. We aimed to screen and assess the antibiotic susceptibility pattern of Staphylococcus aureus isolated from clinical specimens in local hospitals of Northern province in Jordan.Materials and Methods: Staphylococcus aureus was isolated and identified using standard methods from various clinical specimens of different infected body sites from 358 patients during the period from January 2005 to November 2008.Results: Our analysis showed that 31.6% of S. aureus infections were MRSA, while 31% were multidrug resistance (MDR and 42.7% were Oxacillin-resistant (ORSA. Most of these strains were isolated from wound specimens. All isolates were susceptible to vancomycin (100%. They were also susceptible to chloramphenicol, linezolid, nitrofurantoin, rifampicin and teicoplanin (>80%, but showed resistance to erythromycin and penicillin.Conclusion: Vancomycin was the most effective antimicrobial agent against S. aureus. We recommend regular surveillance of hospital associated infections and monitoring antibiotic sensitivity pattern and strict drug policy for antibiotics used within and outside the hospital environments. Keywords: Staphylococcus aureus, MRSA, MDR
Full Text Available Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to many antibiotics. Ceftazidime (CAZ, the synthetic β-lactam, is normally used as the first-line antibiotic therapy for treatment of melioidosis. However, acquired CAZ resistance can develop in vivo during treatment with CAZ, leading to mortality if therapy is not switched to a different antibiotic(s in a timely manner. In this study, susceptibilities of 81 B. pseudomallei isolates to nine different antimicrobial agents were determined using the disk diffusion method, broth microdilution test and Etest. Highest percentage of susceptibility was demonstrated to CAZ, amoxicillin/clavulanic acid, meropenem, imipenem, and trimethoprim/sulfamethoxazole. Although these drugs demonstrated the highest percentage of susceptibility in B. pseudomallei, the overall results underline the importance of the emergence of resistance in this organism. PCR results showed that, of the 81 B. pseudomallei, six multidrug resistant (MDR isolates carried bpeB, amrB, and BPSS1119 and penA genes. Genotyping of the isolates using random amplified polymorphic DNA analysis showed six different PCR fingerprinting patterns generated from the six MDR isolates clusters (A and eight PCR fingerprinting patterns generated for the remaining 75 non-MDR isolates clusters (B.
Lin, Wu-Pu; Wang, Jann-Tay; Chang, Shan-Chwen; Chang, Feng-Yee; Fung, Chang-Phone; Chuang, Yin-Ching; Chen, Yao-Shen; Shiau, Yih-Ru; Tan, Mei-Chen; Wang, Hui-Ying; Lai, Jui-Fen; Huang, I-Wen; Lauderdale, Tsai-Ling
Drug-resistant Klebsiella pneumoniae, especially extended-spectrum β-lactamase (ESBL)- and/or AmpC β-lactamase-producing strains, is an emerging problem worldwide. However, few data focusing on drug susceptibility of K. pneumoniae from community is available. In this study, we analyzed 1016 K. pneumoniae isolates from outpatients or those visiting emergency rooms collected during 2002–2012 from Taiwan Surveillance of Antimicrobial Resistance program. Significantly decreased susceptibilities to 3rd generation cephalosporins and ciprofloxacin were found during the study period. By 2012, susceptibility to cefotaxime and ciprofloxacin was 83.6% and 81.6%, respectively. The prevalence of ESBL-producers increased from 4.8% in 2002 to 11.9% in 2012 (P = 0.012), while that of AmpC β-lactamase-producers increased from 0% to 9.5% in the same period (P ESBL and AmpC-β-lactamase-producers by pulsed-field gel electrophoresis and multi-locus sequence typing revealed wide genetic diversity even among the most common sequence type 11 isolates (33.0%). By multivariate analysis, later study year, elderly, and urine isolates were associated with carriage of ESBL genes, while only urine isolates were associated with carriage of AmpC β-lactamase genes. Further studies are needed to determine which antibiotics are reasonable empirical therapy options for patients presenting with severe sepsis that might be caused by K. pneumoniae. PMID:27824151
Full Text Available Objective: To investigate microorganisms causing bacteremia in Jordanian children and to assess their sensitivity to various groups of antimicrobials."nMethods: A retrospective study was conducted on positive blood cultures taken from 378 children aged below 15 year, who sought medical attention at Princess Rahmah Hospital between January and December/2008."nResults: Out of 4475 tested blood samples, 378 isolates were recovered from blood cultures. The male to female isolate ratio was (1.26:1.0. The most frequent pathogen found was Staphylococcus aureus (86.2%, followed by Klebsiella spp. (9%, Escherichia coli (1.9%, Streptococcus spp. (1.9%, Pseudomonas spp. (0.8%, and Acinetobacter sp. was found in only one culture (0.3%. The susceptibility rate of S. aureus was recorded the highest (99.6% for vancomycin, and the lowest susceptibility rate (3.2% was recorded for aztreonam."nConclusions: Staphylococcus aureus was the main isolate in bacteremic children, with all isolates demonstrating susceptibility to vancomycin. Overall, aztreonam resistance was near 97%, and this rate was not affected by sex and blood isolate type. This information should be considered when empirical therapy is recommended or prescribed for children with bacteremia.
Mekić, S; Matanović, K; Šeol, B
Pseudomonas aeruginosa is a common cause of otitis externa in dogs, and treatment of these infections is becoming problematic because of the increasing number of multiresistant strains. The aim of the present study was to compare the in vitro activities of cefepime, ceftazidime, enrofloxacin, ciprofloxacin, gentamicin and ticarcillin/clavulanic acid against 104 strains of P aeruginosa isolated from dogs with otitis externa. Antimicrobial susceptibility and minimum inhibitory concentrations, in µg/ml, were evaluated by the E test (bioMérieux). The most active compound was ceftazidime, with 100 per cent efficiency. The majority of tested strains were susceptible to ticarcillin/clavulanic acid (89.4 per cent), followed by ciprofloxacin (88.5 per cent) and cefepime (60.6 per cent). The highest resistance was observed to enrofloxacin (51.9 per cent) and gentamicin (43.3 per cent). Large numbers of strains were intermediately susceptible to antibiotics registered for use in veterinary medicine in Croatia--enrofloxacin (47.1 per cent) and gentamicin (41.3 per cent).
Full Text Available Background and aims. The aim of this study is to define the epidemiology and the antimicrobial resistance profile of Ureaplasma spp. and Mycoplasma hominis isolated from urogenital specimens of patients attending the Microbiology and Virology Unit of Padua between January 2014 and December 2015. Materials and methods. The analysis was carried out on a total of 10861 samples. Species identification and antimicrobial susceptibility tests were performed using bioMérieux Mycoplasma IST 2. Results. 2668 samples (24.6% from 2043 patients were positive: 2466 samples positive for Ureaplasma spp. (1897 patients and 8 samples positive for M. hominis (8 patients, while in 194 samples (138 patients was detected a coinfection. As for antimicrobial susceptibility of Ureaplasma spp. we found a resistance (R+I rate of 90.6% for ciprofloxacin, of 74,1% for ofloxacin, of 52.8% for azithromycin and of 47.0% for erythromycin.Conclusions. Our report shows a high prevalence of Ureaplasma spp. in the study population. Surveillance of antibiotic resistance is critical for an appropriate therapeutic approach, which must always be contextualized with patient’s symptomatology.
Silvana Kelie Souza de Almeida Barros
Full Text Available This descriptive quantitative study aimed to analyze the prevalence of microorganisms and the antimicrobial sensitivity profile from urine cultures of patients with catheter-associated urinary tract infection. We reviewed 394 medical records of adults hospitalized in the Intensive Care Units of the University Hospital of Londrina, Paraná, Brazil, from April to December 2011. The prevalence of catheter-associated urinary tract infection was of 34.0% (134 and 2.2% (3 of these patients developed sepsis. The most common microorganisms found in the urine cultures were Candida sp (44.4%, Acinetobacter baumannii (9.7% and Pseudomonas aeruginosa (9.2%. This last one showed resistance of 86.7% to third-generation cephalosporins and the Acinetobacter baumannii showed resistance of 83.3% to carbapenems. Klebsiella pneumonia had 87.5% of resistance to third and fourth generation cephalosporins and 75.0% to carbapenems. We concluded that bacterial resistance is frequent in catheter-associated urinary tract infection and that we should emphasize the control measures.
Thomsen, Natalie A.; Hammer, Katherine A.; Riley, Thomas V.; Van Belkum, Alex; Carson, Christine F.
The aim of this study was to seek additional data on the antimicrobial susceptibility of Staphylococcus spp. after habituation to low levels of the topical antimicrobial agent tea tree (Melaleuca alternifolia) oil. Meticillin-susceptible Staphylococcus aureus (MSSA), meticillin-resistant S. aureus (
Full Text Available Streptococcus pneumoniae is a common pathogenic cause of pediatric infections. This study investigated the serotype distribution, antimicrobial susceptibility, and molecular epidemiology of pneumococci before the introduction of conjugate vaccines in Shanghai, China.A total of 284 clinical pneumococcal isolates (270, 5, 4,3, and 2 of which were isolated from sputum, bronchoalveolar lavage fluid, blood, cerebral spinal fluid, and ear secretions, respectively from children less than 14 years of age who had not been vaccinated with a conjugate vaccine, were collected between January and December in 2013. All isolates were serotyped by multiplex polymerase chain reaction or quellung reactions and antimicrobial susceptibility testing was performed using the broth microdilution method. The molecular epidemiology of S.pneumoniae was analyzed by multilocus sequence typing (MLST.Among the 284 pneumococcal isolates, 19F (33.5%, 19A (14.1%, 23F (12.0%, and 6A (8.8% were the most common serotypes and the coverage rates of the 7-, 10-, and 13-valent pneumococcal conjugate vaccines (PCV7, PCV10, and PCV13 were 58.6%, 59.4% and 85.1%, respectively. Antimicrobial susceptibility showed that the prevalence rates of S.pneumoniae resistance to penicillin were 11.3% (32/284. Approximately 88.0% (250/284 of the isolates exhibited multi-drug resistance. MLST analysis revealed a high level of diversity, with 65 sequence types (STs among 267 isolates. Specifically, the four predominant STs were ST271 (24.3%, 65/267, ST320 (11.2%, 30/267, ST81 (9.7%, 26/267, and ST3173 (5.2%, 14/267, which were mainly associated with serotypes 19F, 19A, 23F, and 6A, respectively.The prevalent serotypes among clinical isolates from children were 19F, 19A, 23F, and 6A and these isolates showed high resistance rates to β-lactams and macrolides. The Taiwan19F-14 clone played a predominant role in the dissemination of pneumococcal isolates in Shanghai, China. Therefore, continued and
DABERNAT, H.J.; Delmas, C F; Tainturier, D J; Lareng, M B
The in vitro susceptibility of recent clinical isolates of Haemophilus equigenitalis to various antimicrobial agents was determined by the disk diffusion test and the World Health Organization-International Collaborative Study agar dilution procedure. Ampicillin and tetracycline were the most active drugs. All strains were susceptible to beta-lactam antibiotics, chloramphenicol, trimethoprim-sulfamethoxazole, nalidixic acid, nitrofurantoin (Furadantin), and bacitracin. All but two strains wer...
Norman, Keri N; Scott, Harvey M; Harvey, Roger B; Norby, Bo; Hume, Michael E
Clostridium difficile can be a major problem in hospitals because the bacterium primarily affects individuals with an altered intestinal flora; this largely occurs through prolonged antibiotic use. Proposed sources of increased community-acquired infections are food animals and retail meats. The objective of this study was to compare the antimicrobial resistance patterns of C. difficile isolated from a closed, integrated population of humans and swine to increase understanding of the bacterium in these populations. Swine fecal samples were collected from a vertically flowing swine population consisting of farrowing, nursery, breeding, and grower/finisher production groups. Human wastewater samples were collected from swine worker and nonworker occupational group cohorts. Antimicrobial susceptibility testing was performed on 523 C. difficile strains from the population using the commercially available agar diffusion Epsilometer test (Etest(®)) for 11 different antimicrobials. All of the swine and human strains were susceptible to amoxicillin/clavulanic acid, piperacillin/tazobactam, and vancomycin. In addition, all of the human strains were susceptible to chloramphenicol. The majority of the human and swine strains were resistant to cefoxitin and ciprofloxacin. Statistically significant differences in antimicrobial susceptibility were found among the swine production groups for ciprofloxacin, tetracycline, amoxicillin/clavulanic acid, and clindamycin. No significant differences in antimicrobial susceptibility were found across human occupational group cohorts. We found that 8.3% of the swine strains and 13.3% of the human strains exhibited resistance to metronidazole. The finding of differences in susceptibility patterns between human and swine strains of C. difficile provides evidence that transmission between host species in this integrated population is unlikely.
Fashae, K; Ogunsola, F; Aarestrup, Frank Møller
BACKGROUND: This study determines the prevalence and antibiotic resistance of Salmonella serovars from humans and chickens in Ibadan, Nigeria, in 2004-2007. METHODOLOGY: A total of 991 blood samples were collected from patients in 2004 to 2005 and 641 fecal samples were collected from poultry farms...... in 2007. All Salmonella isolates were serotyped and tested for antimicrobial susceptibility. RESULTS: Thirty-nine (4%) Salmonella isolates were obtained from human blood and 70 (11%) from chicken fecal samples. The human isolates revealed nine different serovars; 82% were non-typhoidal Salmonella and 18......% were (S. Typhi). The majority of serovars from humans were S. Enteritidis (33%), S. Dublin (18%), and S. Typhimurium (18%). Resistance to chloramphenicol, sulfamethoxazole, trimethoprim, and ampicillin ranged from 36% to 59% for the human isolates. Eight different serovars were obtained from chickens...
Aarestrup, Frank Møller; Nielsen, E. M.; Madsen, Mogens;
. coil isolates originated from humans (7), broilers (17), and pigs (99); and the C. lari isolates originated from broilers (5) and cattle (1), All isolates were susceptible to apramycin, neomycin, and gentamicin, Only a few C.jejuni isolates were resistant to one or more antimicrobial agents, Resistance...... to tetracycline was more common among C.jejuni isolates from humans (11%) than among C, jejuni isolates from animals (0 to 2%), More resistance to streptomycin was found among C, jejuni isolates from cattle (10%) than among those from humans (4%) or broilers (1%), A greater proportion of C. coil than of C, jejuni...... isolates from broilers (18%) and humans (14%), Twenty-four percent of C, coli isolates from pigs were resistant to enrofloxacin, whereas 29% of C, coli isolates from humans and none from broilers were resistant, More resistance to streptomycin was observed among C, coil isolates from swine (48%) than among...
Echániz-Aviles, G; Velázquez-Meza, M E; Carnalla-Barajas, M N; Soto-Noguerón, A; Solórzano-Santos, F; Pérez Miravete, A; Gatica-Marquina, R; di Fabio, J L
As part of the Sistema Regional de Vacunas (SIREVA) initiative, we conducted a surveillance study to determine the relative prevalence of capsular types of Streptococcus pneumoniae and antimicrobial susceptibility of invasive isolates in children less than 5 years old. We collected 220 isolates and found 33 of the 90 known types, with type 23F as the most common followed by types 6A+B, 14, 19F, and 19A. High penicillin resistance was found in 49 strains (22.2%), 31 belonging to type 23F. Twenty-nine (13.1%) were resistant to erythromycin, 95 (43.1%) were resistant to chloramphenicol, and 24 (10.9%) were resistant to cefotaxime. No strains were resistant to vancomycin.
Full Text Available The Clinical Microbiology Laboratory of the University of Genoa participated, during the year 2003, in an international antimicrobial surveillance program.The collection of isolates was done according to the site of infection and/or type of patient. Four hundred twenty (420 clinical isolates were analyzed during this year and the frequencies of the different pathogens were investigated. A reference centre carried out susceptibility tests. Oxacillin-resistant Staphylococcus aureus represented 47.6% of all S. aureus isolates from blood stream infections and 33.3% of all S. aureus isolated from skin and soft tissue infections in hospitalised patients.These strains showed resistance to most of the antimicrobial agents evaluated, except vancomycin, teicoplanin, quinupristin/dalfopristin and linezolid which registered 100% of susceptibility. Some isolates from blood stream infections such as E. coli demonstrated resistance to ciprofloxacin (23.3%, levofloxacin (20%, and gatifloxacin (16.6%, and Klebsiella pneumoniae was resistant (18% to all fluoroquinolones tested. Pseudomonas aeruginosa manifested resistance to ciprofloxacin (16.6%, while 27.7% of these strains were resistant both to levofloxacin and gatifloxacin. All the Enterobacter cloacae isolated from blood were susceptible to ciprofloxacin, levofloxacin and gatifloxacin. Haemophilus influenzae and Moraxella catarrhalis collected from community-acquired respiratory tract infections were all inhibited by ciprofloxacin, levofloxacin and gatifloxacin. E. coli isolated from urinary tract infections in hospitalised patients were resistant to ciprofloxacin, levofloxacin and gatifloxacin (2.7%. All Salmonella spp. collected from samples of patients affected by infections of the gastro-intestinal tract were susceptible to all fluoroquinolones. Penicillin resistance in Streptococcus pneumoniae was found in 21.4% of isolates from patients with respiratory tract infections. Fluoroquinolone resistance was
Full Text Available Purpose: Enteric fever is endemic in India with Salmonella Typhi being the major causative agent. Antibiotic therapy constitutes the mainstay of management. The present study was undertaken to find the susceptibility profile of Salmonella enterica var Typhi (S. Typhi blood isolates in a tertiary care hospital between January 2001 and December 2012. Materials and Methods: A retrospective analysis of laboratory records was carried out. Conventional blood culture method was used until 2009; from January 2010 onwards BACTEC 9240 system has been in use. Salmonella were confirmed by serotyping using group and type specific antisera. Antibiotic susceptibility was performed using the disk diffusion method. In addition 116 isolates were subjected to minimum inhibitory concentration testing for chloramphenicol, ciprofloxacin, amoxicillin and nalidixic acid (NA using agar dilution and for ceftriaxone and azithromycin using E-strips (Biomerieux. Result: A total of 1016 typhoidal salmonellae were obtained. The predominant serotype obtained was S. Typhi (852, 83.8% followed by Salmonella enterica var Paratyphi A (164, 16.2%. We observed a re-emergence of susceptibility to first line antibiotics and a notable decline in multidrug resistant (MDR strains. We also found all recent isolates resistant to NA and susceptible to third generation cephalosporins and 84.5% of isolates having decreasing ciprofloxacin susceptibility using revised criteria as per Clinical and Laboratory Standards Institute 2012 guidelines. Conclusion: There has been re-emergence of susceptibility to first line antibiotics and a notable decline in MDR strains of S. Typhi. We have a very high resistance to NA and decreasing susceptibility to ciprofloxacin. Third generation cephalosporins and azithromycin seem to be effective therapeutic options. Judicious use of these antibiotics is mandatory to prevent emergence of resistant strains.
Léonard Kouegnigan Rerambiah
Conclusions: The antimicrobial resistance profiles seen here are of concern. To control the spread of drug-resistant bacteria, clinicians should be cognizant of their local antimicrobial resistance patterns.
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.
Full Text Available In this study, a total of 90 seafood samples; croaker fish (Pseudotolithus senegalensis, shrimps (Penaeus notialis and blue crab (Callinectes sapidus collected from landing sites along the Lagos Lagoon in Nigeria were examined for the prevalence of Vibrio parahaemolyticus using both biochemical and molecular methods. Biochemical identification of the isolates was confirmed by Polymerase Chain Reaction (PCR. The presence of the virulence-associated tdh (thermostable direct haemolysin, trh1 (thermostable-related haemolysin and trh2 genes in the V. parahaemolyticus isolates was also detected by the PCR method. PCR products from the V.16S primers were sequenced. Antibiotics susceptibility of the isolates was also determined. About, eight isolates were presumptively identified as V. parahaemolyticus, PCR identified five and none of the isolates were positive for the genes tdh or trh. The five isolates sequenced were identified as different strains of V. parahaemolyticus. V. parahaemolyticus_RIMD_2210633 = 2MKSHa remained resistant to all antimicrobials tested. However, only V. parahaemolyticus_MP-2_AY911391 = TBSHy showed strong sensitivity to all the antimicrobials with ampicillin (minimum inhibitory concentration-4 μg/ml. In addition, the other three isolates showed sensitivity for Tetracycline, Ciprofloxacin, Gentamicin and Ceftazidime. Ampicillin resistance in most of the isolates suggests low efficiency of ampicillin in management of V. parahaemolyticus infection.
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.
Xiao-Ping Zhang; Wei-Hong Wang; Yu Tian; Wen Gao; Jiang Li
AIM: To investigate the mechanisms of aspirin increasing the susceptibility of Helicobacter pylori ( H pylori) to metronidazole. METHODS: H pylori reference strain 26 695 and two metronidazole-resistant isolates of H pylori were included in this study. Strains were incubated in Brucella broth with or without aspirin (1 mmol/L). The rdxA gene of H pylori was amplified by PCR and sequenced. The permeability of H pylori to antimicrobials was determined by analyzing the endocellular radioactivity of the cells after incubated with [7-3H]-tetracycline. The outer membrane proteins (OMPs) of H pylori 26 695 were depurated and analyzed by SDS-PAGE. The expression of 5 porins (hopA, hopB, hopC, hopD and hopE) and the putative RND efflux system (hefABC) of H pylori were analyzed using real-time quantitative PCR. RESULTS: The mutations in rdxA gene did not change in metronidazole resistant isolates treated with aspirin. The radioactivity of H pylori increased when treated with aspirin, indicating that aspirin improved the permeability of the outer membrane of H pylori. However, the expression of two OMP bands between 55 kDa and 72 kDa altered in the presence of aspirin. The expression of the mRNA of hopA, hopB, hopC, hopD, hopE and hefA, hefB, hefC of H pylori did not change when treated with aspirin. CONCLUSION: Although aspirin increases the susceptibility of H pylori to metronidazole, it has no effect on the mutations of rdxA gene of H pylori. Aspirin increases endocellular concentrations of antimicrobials probably by altering the OMP expression.
Aarestrup, Frank Møller; Jensen, L. B.
From 1996 to 2001 a total of 467 Staphylococcus hyicus isolates from exudative epidermitis (EE) in pigs in Denmark were examined for susceptibility to 13 different antimicrobial agents. The presence of selected genes encoding macrolide (erm(A), erm(B) and erm(C)), penicillin (blaZ), streptogramin...
Cao, Xiaoli; Cavaco, Lina; Lv, Yuan
A total of 222 urinary Escherichia coli isolates from 20 tertiary hospitals in 15 different provinces and 4 municipalities in mainland China were characterized by antimicrobial susceptibility, phylogrouping, and the presence of plasmid-mediated quinolone resistance genes. A subset of 138 suspecte...
Zhang, Sean X.; Rawte, Prasad; Brown, Shirley; Lo, Steven; Siebert, Heather; Pong-Porter, Sylvia; Low, Donald E.; Jamieson, Frances B.
Both the CLSI agar dilution method and Trek Sensititre broth microdilution panel for Streptococcus pneumoniae antimicrobial susceptibility testing were evaluated against the reference CLSI broth microdilution method using the most recently published CLSI breakpoints. While agar dilution was not an optimal method, the commercial panel appeared to be an acceptable method, with minor errors encountered for ceftriaxone, penicillin, and meropenem. PMID:21123533
Full Text Available Background High incidences of dysentery and diarrhea were reported in a pediatric hospital in Ahvaz, Iran during March to April, 2013. Objectives A cross-sectional study was therefore undertaken to identify the causative agents. Patients and Methods A total of 230 diarrhea samples were collected from the patients and analyzed by routine bacteriological methods. Bacterial identification, serological assay, antimicrobial susceptibility testing, extended spectrum β-lactamases (ESBLs screening and plasmid profile analysis were performed according to the standard guidelines. Results A total of 70 Shigella strains including %70 (n = 49 S. sonnei and 30% (n = 21 S. flexneri were isolated from diarrhea samples. Most of the Shigella isolates showed high degrees of resistance to ampicillin, ulafamethoxazole- trimethoprime and cefexim. Concurrent resistance to sulafametoxazole- trimethoprime and ampicillin was the most common resistance pattern. Overall, 11.4% of Shigella isolates showed the ESBL producer criteria. The plasmid profile patterns of all the strains were determined by a modified alkaline lysis method. By plasmid profile analysis 23 genotypes were identified among all the isolates, 14 and 9 genotypes among the S. sonnei and S. flexneri respectively. S. sonnei and S. flexneri isolates demonstrated unique plasmid profiles. Conclusions These data demonstrated that S. sonnei strains are the main cause of shigellosis as the prevalent Shigella serotype in Iran. We also found that the antibiotic resistance rates are increasing among Shigella strains. Plasmid profile analysis is more reliable than antibiotic susceptibility patterns in epidemiologic studies.
Full Text Available Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA has become increasingly prevalent worldwide since it was first reported in a British hospital. The prevalence however, varies markedly in hospitals in the same country, and from one country to another. We therefore sought to document comprehensively the prevalence and antimicrobial susceptibility pattern of MRSA isolates in Trinidad and Tobago. Methods All Staphylococcus aureus isolates encountered in routine clinical specimens received at major hospitals in the country between 2000 and 2001 were identified morphologically and biochemically by standard laboratory procedures including latex agglutination test (Staphaurex Plus; Murex Diagnostics Ltd; Dartford, England; tube coagulase test with rabbit plasma (Becton, Dickinson & Co; Sparks, MD, USA, and DNase test using DNase agar (Oxoid Ltd; Basingstoke, Hampshire, England. MRSA screening was performed using Mueller-Hinton agar containing 6 μg oxacillin and 4% NaCl, latex agglutination test (Denka Seiken Co. Ltd, Tokyo, Japan and E-test system (AB Biodisk, Solna, Sweden. Susceptibility to antimicrobial agents was determined by the modified Kirby Bauer disc diffusion method while methicillin MICs were determined with E-test system. Results Of 1,912 S. aureus isolates received, 12.8% were methicillin (oxacillin resistant. Majority of the isolates were recovered from wound swabs (86.9% and the least in urine (0.4% specimens. Highest number of isolates was encountered in the surgical (62.3% and the least from obstetrics and gynaecology (1.6% facilities respectively. Large proportions of methicillin sensitive isolates are >85% sensitive to commonly used and available antimicrobials in the country. All MRSA isolates were resistant to ceftriaxone, erythromycin, gentamicin and penicillin but were 100% sensitive to vancomycin, rifampin and chloramphenicol. Conclusion There is a progressive increase in MRSA prevalence in the country but
Kádár, Béla; Kocsis, Béla; Kristof, Katalin; Tóth, Ákos; Szabó, Dóra
In this study susceptibility to different antimicrobial peptides was investigated on colistin-susceptible and colistin-resistant identical pulsotype strains of KPC-2 producing Klebsiella pneumoniae ST258 as well as colistin-susceptible and colistin-resistant Enterobacter asburiae strains isolated from clinical samples. In our test, bacteria were exposed to 50 mg/ml lactoferrin, lysozyme and protamine - cationic antimicrobial peptides belonging to innate immune system and having structural similarity to polymyxins - in separate reactions. After 18 hours incubation of colonies were counted. 40% of colistin-resistant K. pneumoniae strains and 97% of colistin-susceptible counterpart strains were lysed by protamine whereas 87% and 100% colony forming unit decrease by lysozyme was seen, respectively. In the case of colistin-resistant E. asburiae strains 1 log10 cell count increase were observed after treatment with lysozyme and 1.56 log10 after lactoferrin exposure compared to the initial number whereas the colistin-susceptible showed no relevant cell count increase. Our findings suggest that acquired colistin-resistance in Enterobacteriaceae is associated with tolerance against antimicrobial peptides.
Full Text Available Campylobacter jejuni is one of the leading causes of sporadic food-borne bacterial disease in humans. In intensive poultry and pig rearing systems the use of oral antibiotics is essential to maintain health. Consequently, there is a high risk for the thermophilic Campylobacter jejuni and C. coli resident in the intestinal tract of food animals to develop resistance to commonly used antibiotics. Contamination of meat or eggs with pathogenic strains of resistant Campylobacter could, therefore, result in a form of campylobacteriosis in humans that is difficult to treat. The aim of this investigation was to determine the antimicrobial susceptibility of thermophilic Campylobacter spp. isolated from pigs and poultry by the broth microdilution minimum inhibitory concentration (MIC test. A total of 482 samples from the Western Cape and Gauteng provinces was collected and analysed. Thirty-eight Campylobacter isolates were obtained. Analysis of data revealed that C. jejuni strains mainly of poultry origin were more resistant to the fluoroquinolones, macrolides and tetracyclines and the C. coli strains were more resistant to the macrolides and lincosamides. Multiresistance was also detected in 4 Campylobacter strains from the Western Cape. With the exception of tetracyclines, strains from high health Gauteng broiler farms were susceptible to antibiotics used to treat Campylobacter infections.
Misra, Richa; Prasad, Kashi Nath
Decreased ciprofloxacin susceptibility (DCS) and multidrug resistance in typhoidal Salmonella isolates in areas of endemicity are significant therapeutic problems. Guidelines for azithromycin disc diffusion and MIC interpretive criteria for Salmonella enterica serovar Typhi were published recently by the Clinical and Laboratory Standards Institute in 2015. We investigated the antimicrobial susceptibility pattern of azithromycin in 100 isolates of Salmonella Typhi (n=80), Paratyphi A (n=18) and B (n=2) recovered from bloodstream infections from January 2013 to December 2015. Zone sizes were extrapolated against MIC values, and a scatter plot was constructed. The azithromycin MICs by Etest ranged from 2 to 16 µg ml-1, while the disc diffusion diameters were from 13 to 22 mm. We observed that the margin of the zone of inhibition around the azithromycin disc may not be very clear and therefore difficult to interpret and that there was wide variation in the zone sizes for the same MIC value in both serovars. DCS was observed in 85 % of Salmonella Typhi recovered (68/80) and in 15/18 (83.3 %) Paratyphi A isolates. Judicious use of azithromycin is advocated as an alternative oral agent in endemic areas where DCS is common.
Jonker, A; Picard, J A
Campylobacter jejuni is one of the leading causes of sporadic food-borne bacterial disease in humans. In intensive poultry and pig rearing systems the use of oral antibiotics is essential to maintain health. Consequently, there is a high risk for the thermophilic Campylobacter jejuni and C. coli resident in the intestinal tract of food animals to develop resistance to commonly used antibiotics. Contamination of meat or eggs with pathogenic strains of resistant Campylobacter could, therefore, result in a form of campylobacteriosis in humans that is difficult to treat. The aim of this investigation was to determine the antimicrobial susceptibility of thermophilic Campylobacter spp. isolated from pigs and poultry by the broth microdilution minimum inhibitory concentration (MIC) test. A total of 482 samples from the Western Cape and Gauteng provinces was collected and analysed. Thirty-eight Campylobacter isolates were obtained. Analysis of data revealed that C. jejuni strains mainly of poultry origin were more resistant to the fluoroquinolones, macrolides and tetracyclines and the C. coli strains were more resistant to the macrolides and lincosamides. Multi-resistance was also detected in 4 Campylobacter strains from the Western Cape. With the exception of tetracyclines, strains from high health Gauteng broiler farms were susceptible to antibiotics used to treat Campylobacter infections.
Full Text Available The antibiotic susceptibility and antimicrobial activity, as food safety parameters important for application of autochthonous lactic acid bacteria (LAB, that previously satisfied technological criteria for functional starter cultures in fresh cheese production were examined. Soluble whole cell protein patterns of autochthonous LAB strains from fresh cheese, obtained by SDS-PAGE, revealed the presence of two predominant strains, which were identified as Lactobacillus fermentum A8 and Enterococcus faecium A7. These strains were not resistant and shown susceptibility to antibiotics: ampicillin, bacitracin, penicillin G, azithromycin, chloramphenicol, clarithromycin, clindamycin, spiramycin, tetracycline, streptomycin, neomycin, gentamicin, erythromycin, rifampicin and novobiocin. Lb. fermentum A8 strain displayed phenotypic resistance to vancomycin, but this resistance is intrinsic, not transferable and it is acceptable from the safety aspect. The capacity of Lb. fermentum A8 and Ec. faecium A7 to inhibit growth of test-microorganisms Listeria monocytogenes ATCC 11911, Escherichia coli 3014, Salmonella enterica serovar Typhimurium FP1 and Staphylococcus aureus 3048, was also analysed. According to obtained results, Lb. fermentum A8 and Ec. faecium A7 are safe from the aspect of spreading antibiotic resistance and could be useful as bioprotective cultures that inhibit common bacterial food contaminants, including L. monocytogenes.
Xiao, Meng; Wang, Yao; Yang, Qi-Wen; Fan, Xin; Brown, Mitchell; Kong, Fanrong; Xu, Ying-Chun
The aim of this study was to review the antimicrobial susceptibility of Pseudomonas aeruginosa in China from two nationwide surveillance programmes, namely Surveillance by Etest and Agar Dilution of Nationwide Isolate Resistance (SEANIR) and the Study for Monitoring Antimicrobial Resistance Trends (SMART). A total of 1479 and 187 P. aeruginosa isolates were collected in SEANIR 2005-2008 and SMART 2008-2010, respectively. Minimum inhibitory concentrations of β-lactam/β-lactamase inhibitor combinations, cephalosporins, carbapenems, aminoglycosides and fluoroquinolones were determined and were interpreted following recently revised Clinical and Laboratory Standards Institute (CLSI) guidelines. From SMART, isolation rates of P. aeruginosa were observed to increase by year; moreover, decreasing trends in activity of all antimicrobials were seen. Multidrug-resistant P. aeruginosa strains accounted for 25.2% of SEANIR and 23.0% of SMART isolates. By applying new CLSI interpretive criteria, susceptibilities to piperacillin/tazobactam and carbapenems decreased by 5.4-12.8%. Antimicrobial resistance of the pseudomonads, including P. aeruginosa, remains a challenge for clinical treatment in China. This review emphasises the need for antibiotic stewardship and longitudinal surveillance.
Full Text Available Staphylococcus Aureus (SA is one of the most prevalent bacterial pathogens in human beings. Approximately 20% of healthy persons are persistent carriers and 60% are intermittent carriers of SA. Nasal cavity is one of the most important sites of its colonization. Intravenous (IV drug abuse has been proposed as a risk factor for colonization of SA in the nasal mucosa. The goal of this study was to determine the frequency of SA carriers in nasal cavity among IV and non-IV drug abusers (addicts, as well as to assess the antimicrobial susceptibility pattern of the positive cases. In a cross-sectional analysis of 300 drug addicts (Group I: 100 non-injecting addicts, Group II: 100 IV injecting drug addicts in rehab, Group III: 100 IV injecting drug addicts not in rehab in the infectious diseases clinics of Tabrizâs Imam Reza and Sina teaching hospitals and the rehabilitation center of Razi hospital, were investigated. Hospitalized addicts, insulin-dependent diabetic cases, HIV positive patients and those on chronic hemodialysis were excluded. The nasal mucosal sample was prepared from each case for SA isolation and its antimicrobial susceptibility was investigated by antibiogram. Eighty-four cases (28% were culture positive for SA, including 26 cases in group one, 32 cases in group two and 26 cases in group three (p = 0.55. There was only one MRSA isolate present in all the cases studied (1.2%. No resistance to linozolid, rifampin and vancomycin was observed. The resistance to erythromycin, cefoxitin, ciprofloxacin, clindamycin, co-trimoxazol and gentamicin were 3.6, 4.8, 2.4, 3.6, 1.2 and 2.4% respectively. No statistically significant differences existed between the three groups in antibacterial susceptibility pattern. Sensitivity to oxacillin using the E-test results and disc diffusion were completely consistent. The percentage of carries of SA in the anterior nasal mucosa among IV and non-IV drug addicts is not considerably higher than the
Liu, Hsi; Taylor, Thomas H; Pettus, Kevin; Trees, David
We studied whether the Etest can be used as an alternative to agar dilution to determine antimicrobial susceptibilities of ceftriaxone, cefixime, and cefpodoxime in Neisseria gonorrhoeae surveillance. One hundred fifteen clinical and laboratory isolates of N. gonorrhoeae were tested following the Clinical Laboratory Improvement Amendments (CLIA)-approved CLSI standard agar dilution method and, separately, by the Etest according to the manufacturer's recommendations. The MICs were determined and compared. Ten laboratory-generated mutants were used to simulate substantially nonsusceptible specimens. The Etest and agar dilution methods were well correlated. Statistical tests produced regression R2 values of 88%, 82%, and 85% and Pearson correlation coefficients of 92%, 91%, and 92% for ceftriaxone, cefixime, and cefpodoxime, respectively. When paired comparisons were made, the two tests were 88.7%, 80%, and 87% within 1 log2 dilution from each other for ceftriaxone, cefixime, and cefpodoxime, respectively. The within-2-log2 agreements were 99.1%, 98.3%, and 94.8% for ceftriaxone, cefixime, and cefpodoxime, respectively. Notwithstanding the good correlations and the within-2-log2 general agreement, the Etest results produced slightly lower MICs than the agar dilution results. In conclusion, we found that the Etest can be effectively used as an alternative to agar dilution testing to determine the susceptibility of N. gonorrhoeae to ceftriaxone, cefixime, and cefpodoxime, although we recommend further research into extremely resistant isolates. For isolates within the typical range of clinical MICs, reexamination of the Etest interpretation of susceptible and nonsusceptible categories would likely allow for successful transition from agar dilution to the Etest.
Kobayashi, H; Sonmez, N; Morozumi, T; Mitani, K; Ito, N; Shiono, H; Yamamoto, K
Fifty-four Japanese strains of Mycoplasma hyosynoviae isolated from porkers during 1980 to 1995, and 107 Japanese strains of M. hyorhinis isolated from piglets with respiratory disease during 1991 to 1994 were investigated for the in vitro activities of 13 antimicrobial agents [josamycin, tylosin, spiramycin, kitasamycin, erythromycin, lincomycin (LCM), kanamycin (KM), chloramphenicol (CP), thiamphenicol (TP), tiamulin (TML), oxytetracycline (OTC), chlortetracycline (CTC), and enrofloxacin (ERFX)] by the agar dilution method. Of the drugs tested TML showed the highest activity with minimum inhibitory concentration (MIC) of 0.013 to 0.1 microgram/ m/ (MIC90; 0.05 microgram/ml) against strains of M. hyosynoviae, and 0.2 to 0.78 microgram/ml (MIC90; 0.39 microgram/ml) against strains of M. hyorhinis. ERFX, LCM, most of the 16-membered macrolide antibiotics and tetracyclines also showed low MICs against both mycoplasma species. The susceptibility of KM, CP and TP to the mycoplasmas was considered to be of a secondary grade. Two of 54 strains of M. hyosynoviae, and 11 of 107 strains of M. hyorhinis showed resistance to all 14- and 16-membered macrolide antibiotics tested. Tetracyclines (OTC and CTC) showed a relatively broad MIC distribution from 0.1 to 6.25 micrograms/ml against the M. hyosynoviae strains tested. All of the strains isolated during 1980 to 1984 were susceptible at the concentration of 0.78 microgram/ml or less (MIC90; 0.78 microgram/ml) to OTC and 1.56 micrograms/ml or less (MIC90; 1.56 micrograms/ml) to CTC, while the susceptibility of strains isolated recently, during 1994 to 1995, was more than 0.78 microgram/ml (MIC90; 3.13 micrograms/ml) to OTC, and more than 1.56 micrograms/ml (MIC90; 6.25 micrograms/ml) to CTC.
Cuesta, Isabel; Bielza, Concha; Larrañaga, Pedro; Cuenca-Estrella, Manuel; Laguna, Fernando; Rodriguez-Pardo, Dolors; Almirante, Benito; Pahissa, Albert; Rodríguez-Tudela, Juan L.
European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints classify Candida strains with a fluconazole MIC ≤ 2 mg/liter as susceptible, those with a fluconazole MIC of 4 mg/liter as representing intermediate susceptibility, and those with a fluconazole MIC > 4 mg/liter as resistant. Machine learning models are supported by complex statistical analyses assessing whether the results have statistical relevance. The aim of this work was to use supervised classification algorithms to analyze the clinical data used to produce EUCAST fluconazole breakpoints. Five supervised classifiers (J48, Correlation and Regression Trees [CART], OneR, Naïve Bayes, and Simple Logistic) were used to analyze two cohorts of patients with oropharyngeal candidosis and candidemia. The target variable was the outcome of the infections, and the predictor variables consisted of values for the MIC or the proportion between the dose administered and the MIC of the isolate (dose/MIC). Statistical power was assessed by determining values for sensitivity and specificity, the false-positive rate, the area under the receiver operating characteristic (ROC) curve, and the Matthews correlation coefficient (MCC). CART obtained the best statistical power for a MIC > 4 mg/liter for detecting failures (sensitivity, 87%; false-positive rate, 8%; area under the ROC curve, 0.89; MCC index, 0.80). For dose/MIC determinations, the target was >75, with a sensitivity of 91%, a false-positive rate of 10%, an area under the ROC curve of 0.90, and an MCC index of 0.80. Other classifiers gave similar breakpoints with lower statistical power. EUCAST fluconazole breakpoints have been validated by means of machine learning methods. These computer tools must be incorporated in the process for developing breakpoints to avoid researcher bias, thus enhancing the statistical power of the model. PMID:19433568
Disassa, Nigatu; Sibhat, Berhanu; Muktar, Yimer; Belina, Dinaol
A cross-sectional study was conducted from October 2014 to July 2015 to determine the prevalence and populations of E. coli as well as the prevalence and antimicrobial susceptibility of E. coli O157:H7 isolated from raw milk. Biochemical and serological tests methods were used to confirm E. coli and E. coli O157:H7 and isolates were subjected to antimicrobial susceptibility test using the agar disc diffusion method. Out of 380 raw milk samples examined, 129 (33.9%) and 11 (2.9%) were contaminated with E. coli and E. coli O157:H7, respectively. The highest prevalence was recorded in samples obtained from vendors (39.1%, 4.978 ± 0.180 log10/ml) compared with samples from farmers (28.1%, 3.93 ± 0.01 log10/ml) with significant differences (P = 0.02). The frequency of contamination was higher in the samples collected from milk that was stored and transported in plastic containers (39.4%) than in the containers made of stainless steel (23.0%) (P = 0.002). The antimicrobial susceptibility profile showed that E. coli O157:H7 were resistant to tetracycline (81.8%), streptomycin (81.8%), and kanamycin (63.6%). Milk samples were produced and handled under poor hygienic conditions, stored, and transported in inappropriate containers and under temperature abuse conditions leading to high health risk to the consumers. Additional studies would be needed to establish association between the occurrences of E. coli O157:H7 in raw milk and all the risk factors involved in and around Asosa town. PMID:28316862
Rasmussen, Jon Bjarke; Knudsen, Jenny Dahl; Arpi, Magnus;
OBJECTIVES: The objective of the present study was to compare the efficacy of cefuroxime with that of dicloxacillin as definitive antimicrobial therapy in methicillin-susceptible Staphylococcus aureus bacteraemia (MS-SAB) using a Danish bacteraemia database, information on the indication for anti......OBJECTIVES: The objective of the present study was to compare the efficacy of cefuroxime with that of dicloxacillin as definitive antimicrobial therapy in methicillin-susceptible Staphylococcus aureus bacteraemia (MS-SAB) using a Danish bacteraemia database, information on the indication...... for antimicrobial therapy, multivariate adjustment and propensity score (PS) matching. METHODS: This was a retrospective cohort study. MS-SAB cases from 1 January 2006 to 31 December 2008 were included from a total of seven hospitals in the greater Copenhagen area and seven hospitals in the North Denmark Region....... Information including demographics, antimicrobial therapy and clinical condition was obtained. The physician's note detailing the indication for starting empirical antimicrobial therapy was given special attention. Hazard ratios (HRs) and 95% CIs for 30 day and 90 day mortality were calculated using PS...
Tu, Thanh Dung; Haesebrouck, Freddy; Nguyen, Anh Tuan; Sorgeloos, Patrick; Baele, Margo; Decostere, Annemie
The purpose of this study was to assess the in vitro susceptibility of 64 Vietnamese isolates of Edwardsiella ictaluri, the causal agent of the infectious disease Bacillus Necrosis Pangasius in Pangasianodon hypophthalmus, using the agar dilution technique. All isolates originated from different farms and were collected between 2002 and 2005. None of the isolates displayed acquired resistance to amoxicillin, amoxicillin-clavulanic acid, chloramphenicol, florfenicol, gentamicin, kanamycin, neomycin, and nitrofurantoin. Acquired resistance to streptomycin was detected in 83%, to oxytetracycline in 81%, and to trimethoprim in 71% of the isolates, as indicated by a bimodal distribution of the minimal inhibitory concentrations (MICs) of these antimicrobials. The MICs of enrofloxacin displayed a monomodal distribution with tailing toward the higher MIC values, possibly indicating reduced susceptibility of a minority of isolates (3 out of the 64). For the quinolone antimicrobial agents flumequin and oxolinic acid, acquired resistance was encountered in 8% and 6% of the strains, respectively. All strains were intrinsically resistant to the polypeptide antimicrobial agent colistin. Seventy-three percent of the isolates were shown to have acquired resistance to at least three antimicrobial agents. The results of this study emphasize the strict need to control both the prophylactic and curative use of antimicrobial agents in Vietnamese aquaculture.
Mastitis occurs in numerous species. Antimicrobial agents are used for treatment of infectious mastitis in dairy cattle, other livestock, companion animals, and humans. Mastitis is an economically important disease of dairy cattle and most mastitis research has focused on epidemiology and control of bovine mastitis. Antibiotic treatment of clinical and subclinical mastitis in dairy cattle is an established component of mastitis control programs. Research on the treatment of clinical and subclinical mastitis in other dairy species such as sheep and goats has been less frequent, although the general principles of mastitis therapy in small ruminants are similar to those of dairy cattle. Research on treatment of clinical mastitis in humans is limited and as for other species empirical treatment of mastitis appears to be common. While antimicrobial susceptibility testing is recommended to direct treatment decisions in many clinical settings, the use of susceptibility testing for antibiotic selection for mastitis treatments of dairy cattle has been challenged in a number of publications. The principle objective of this review is to summarize the literature evaluating the question, "Does antimicrobial susceptibility predict treatment outcome for intramammary infections caused by common bacterial pathogens?" This review also addresses current issues related to antimicrobial use and treatment decisions for mastitis in dairy cattle. Information on treatment of mastitis in other species, including humans, is included although research appears to be limited. Issues related to study design, gaps in current knowledge and opportunities for future research are identified for bovine mastitis therapy.
Simjee, Shabbir; McDermott, Patrick F; White, David G; Hofacre, Charles; Berghaus, Roy D; Carter, Peggy J; Stewart, Leigh; Liu, Tongrui; Maier, Marie; Maurer, John J
Data on the prevalence of antimicrobial resistant enterococci and staphylococci from the poultry production environment are sparse in the United States. This information is needed for science-based risk assessments of antimicrobial use in animal husbandry and potential public-health consequences. In this study, we assessed the susceptibility of staphylococci and enterococci isolated from poultry litter, recovered from 24 farms across Georgia, to several antimicrobials of veterinary and human health importance. Among the 90 Enterococcus isolates recovered, E. hirae (46%) was the most frequently encountered species, followed by E. faecium (27%), E. gallinarum (12%), and E. faecalis (10%). Antimicrobial resistance was most often observed to tetracycline (96%), followed by clindamycin (90%), quinupristin-dalfopristin (62%), penicillin (53%), erythromycin (50%), nitrofurantoin (49%), and clarithromycin (48%). Among the 110 staphylococci isolates recovered, only coagulase-negative staphylococci (CNS) were identified with the predominant Staphylococcus species being S. sciuri (38%), S. lentus (21%), S. xylosus (14%) and S. simulans (12%). Resistance was less-frequently observed among the Staphylococcus isolates for the majority of antimicrobials tested, as compared with Enterococcus isolates, and was primarily limited to clarithromycin (71%), erythromycin (71%), clindamycin (48%), and tetracycline (38%). Multidrug resistance (MDR) phenotypes were prevalent in both Enterococcus and Staphylococcus; however, Enterococcus exhibited a statistically significant difference in the median number of antimicrobials to which resistance was observed (median = 5.0) compared with Staphylococcus species (median = 3.0). Because resistance to several of these antimicrobials in gram-positive bacteria may be attributed to the shuttling of common drug-resistance genes, we also determined which common antimicrobial-resistance genes were present in both enterococci and staphylococci. The
Experimental study of the impact of antimicrobial treatments on Campylobacter, Enterococcus and PCR-capillary electrophoresis single-strand conformation polymorphism profiles of the gut microbiota of chickens.
Mourand, Gwenaëlle; Jouy, Eric; Bougeard, Stéphanie; Dheilly, Alexandra; Kérouanton, Annaëlle; Zeitouni, Salman; Kempf, Isabelle
An experiment was conducted to compare the impact of antimicrobial treatments on the susceptibility of Campylobacter, Enterococcus faecium and Enterococcus faecalis, and on the diversity of broiler microbiota. Specific-pathogen-free chickens were first orally inoculated with strains of Campylobacter and Enterococcus faecium. Birds were then orally treated with recommended doses of oxytetracycline, sulfadimethoxine/trimethoprim, amoxicillin or enrofloxacin. Faecal samples were collected before, during and after antimicrobial treatment. The susceptibility of Campylobacter, Enterococcus faecium and Enterococcus faecalis strains isolated on supplemented or non-supplemented media was studied and PCR-capillary electrophoresis single-strand conformation polymorphism (CE-SSCP) profiles of the gut microbiota were analysed. Enrofloxacin-resistant Campylobacter were selected in the enrofloxacin-treated group and showed the Thr86Ile mutation in the gyrA gene. Acquisition of the tetO gene in Campylobacter coli isolates was significantly more frequent in birds given oxytetracycline. No impact of amoxicillin treatment on the susceptibility of Campylobacter could be detected. Ampicillin- and sulfadimethoxine/trimethoprim-resistant Enterococcus faecium were selected in amoxicillin-treated broilers, but no selection of the inoculated vancomycin-resistant Enterococcus faecium could be detected, although it was also resistant to tetracycline and sulfadimethoxine/trimethoprim. PCR-CE-SSCP revealed significant variations in a few peaks in treated birds as compared with non-treated chickens. In conclusion, antimicrobial treatments perturbed chicken gut microbiota, and certain antimicrobial treatments selected or co-selected resistant strains of Campylobacter and Enterococcus.
Full Text Available Vibrio parahaemolyticus is a marine and estuarine bacterium that has been the leading cause of foodborne outbreaks which leads to a significant threat to human health worldwide. Consumption of seafood contaminated with Vibrio parahaemolyticus causes acute gastroenteritis in individuals. The bacterium poses two main virulence factor including the thermostable direct hemolysin (tdh which is a pore-forming protein that contributes to the invasiveness of the bacterium in humans and TDH-related hemolysin (trh, which plays a similar role as thermostable direct hemolysin (tdh in the disease pathogenesis. This study aimed to investigate the antimicrobial resistance Vibrio parahaemolyticus strains in shrimps purchased from wetmarkets and supermarkets. The toxR-based PCR assay indicated that a total of 57.8% (185/320 isolates were positive for V. parahaemolyticus. Only 10% (19/185 toxR-positive isolate exhibit the TDH-related hemolysin (trh gene and none of the isolates were tested positive for thermostable direct hemolysin (tdh. The MAR index was measured for 14 common antimicrobial agents. The results indicated 98% of the isolates were highly susceptible to imipenem, ampicillin sulbactam (96%, chloramphenicol (95%, trimethoprim-sulfamet (93%, gentamicin (85%, levofloxacin (83% and tetracycline (82%. The chloramphenicol (catA2 and kanamycin (aphA-3 resistance genes were detected in the resistant V. parahaemolyticus isolates. Our results demonstrate that shrimps are contaminated with V. parahaemolyticus, some of which carry the trh-gene thus being potential to cause food borne illness. The occurrence of multidrug resistance strains in the environment could be an indication of excessive usage of antibiotics in agriculture and aquaculture fields.
Letchumanan, Vengadesh; Yin, Wai-Fong; Lee, Learn-Han; Chan, Kok-Gan
Vibrio parahaemolyticus is a marine and estuarine bacterium that has been the leading cause of foodborne outbreaks which leads to a significant threat to human health worldwide. Consumption of seafood contaminated with V. parahaemolyticus causes acute gastroenteritis in individuals. The bacterium poses two main virulence factor including the thermostable direct hemolysin (tdh) which is a pore-forming protein that contributes to the invasiveness of the bacterium in humans and TDH-related hemolysin (trh), which plays a similar role as tdh in the disease pathogenesis. This study aimed to investigate the antimicrobial resistance V. parahaemolyticus strains in shrimps purchased from wetmarkets and supermarkets. The toxR-based PCR assay indicated that a total of 57.8% (185/320) isolates were positive for V. parahaemolyticus. Only 10% (19/185) toxR-positive isolate exhibit the trh gene and none of the isolates were tested positive for tdh. The MAR index was measured for 14 common antimicrobial agents. The results indicated 98% of the isolates were highly susceptible to imipenem, ampicillin sulbactam (96%), chloramphenicol (95%), trimethoprim-sulfamethoxazole (93%), gentamicin (85%), levofloxacin (83%), and tetracycline (82%). The chloramphenicol (catA2) and kanamycin (aphA-3) resistance genes were detected in the resistant V. parahaemolyticus isolates. Our results demonstrate that shrimps are contaminated with V. parahaemolyticus, some of which carry the trh-gene thus being potential to cause food borne illness. The occurrence of multidrug resistance strains in the environment could be an indication of excessive usage of antibiotics in agriculture and aquaculture fields.
Full Text Available Background: The members of the genus Acinetobacter are Gram-negative cocobacilli that are frequently found in the environment but also in the hospital setting where they have been associated with outbreaks of nosocomial infections such as meningitis, endocarditis, skin and soft tissue infections, urinary tract infection, conjunctivitis, burn wound infection and bacteremia. This organism has been shown resistance to different antimicrobial agents. The aim of this study was to determination antibiotic resistance profile of Acinetobacter strains isolated from hospitalized patients in Taleghani hospital (Ahvaz, Iran. Materials and Methods: This cross-sectional study was conducted on 43 Acinetobacter strains isolated from hospitalized patients. Clinical specimens were cultured on microbiological media. Subsequently, drug susceptibility test was performed using the disc diffusion method according to CLSI recommendations. Results: Acinetobacter strains were isolated from different specimens consisting biopsy 24 (55.8%, wound 13 (30/2% and blood 6 (14%. In antimicrobial susceptibility testing, colistin exhibited the greatest activity (60.5% against isolated strains. 33 (76/7% isolates demonstrated resistance to imipenem. Conclusion: In outbreak situations, surveillance cultures of patients involved in the outbreak or who are deemed at risk for colonization/infection with the outbreak organism are often parts of the planned intervention.
Full Text Available INTRODUCTION: Stenotrophomonas maltophilia is acquiring increasing importance as a nosocomial pathogen. METHODS: We retrospectively studied the characteristics and outcome of patients with any type of S. maltophilia infection at the University Hospital of Heraklion, Crete, Greece, between 1/2005-12/2010. S. maltophilia antimicrobial susceptibility was tested with the agar dilution method. Prognostic factors for all-cause in-hospital mortality were assessed with multivariate logistic regression. RESULTS: Sixty-eight patients (median age: 70.5 years; 64.7% males with S. maltophilia infection, not related to cystic fibrosis, were included. The 68 patients were hospitalized in medical (29.4%, surgical (26.5%, hematology/oncology departments (23.5%, or the intensive care units (ICU; 20.6%. The most frequent infection types were respiratory tract (54.4%, bloodstream (16.2%, skin/soft tissue (10.3%, and intra-abdominal (8.8% infection. The S. maltophilia-associated infection was polymicrobial in 33.8% of the cases. In vitro susceptibility was higher to colistin (91.2%, trimethoprim/sulfamethoxazole and netilmicin (85.3% each, and ciprofloxacin (82.4%. The empirical and the targeted treatment regimens were microbiologically appropriate for 47.3% and 63.6% of the 55 patients with data available, respectively. Most patients received targeted therapy with a combination of agents other than trimethoprim/sulfamethoxazole. The crude mortality and the mortality and the S. maltophilia infection-related mortality were 14.7% and 4.4%, respectively. ICU hospitalization was the only independent prognostic factor for mortality. CONCLUSION: S. maltophilia infection in a general hospital can be associated with a good prognosis, except for the patients hospitalized in the ICU. Combination reigmens with fluoroquinolones, colistin, or tigecycline could be alternative treatment options to trimethoprim/sulfamethoxazole.
Chuma, Takehisa; Kawamoto, Toshio; Shahada, Francis; Fujimoto, Hideki; Okamoto, Karoku
The determination of antimicrobial minimum inhibitory concentration (MIC) in Erysipelothrix rhusiopathiae by using the agar dilution method has not been covered by the Clinical and Laboratory Institute (CLSI). Only the broth microdilution method has been outlined. This report describes a modification of the agar dilution procedure for E. rhusiopathiae using Trypto-soy agar supplemented with 0.1% Tween 80 and incubation in ambient air at 37 degrees C for 24 hr. The MICs of the assay were in agreement with those of the broth microdilution method recommended by the CLSI. Antimicrobial susceptibility test was performed using this method for 149 E. rhusiopathiae isolates from 2 meat processing plants in Kagoshima Prefecture during the period of April 2004 to March 2005. The number of strains resistant to oxytetracycline, erythromycin, lincomycin, ofloxacin and enrofloxacin were 56 (37.6%), 4 (2.7%), 18 (12.1%), 21 (14.1%) and 19 (12.8%), respectively. All strains were susceptible to ampicillin.
F. T. Weber
Full Text Available The antimicrobial susceptibility of 64 strains of S. pneumoniae obtained from three hospitals in Porto Alegre, Brazil, isolated between 2004 and 2005, was determined, using the agar-dilution method. The prevalence of resistant (intermediate and full resistance strains to trimethoprim/sulphamethoxazole, penicillin, tetracycline, erythromycin, chloramphenicol, and ceftriaxone were 68%, 28%, 18%, 15%, 3%, and 1%, respectively. All strains were susceptible to vancomycin. Among 18 penicillin-resistant strains, 7 were resistant to at least two other antimicrobial drugs. All erythromycin-resistant strains, except one, contained the erm(B and/or mef(A/E genes, with a predominance of the former. The resistance rate to penicillin and erythromycin in Porto Alegre remained stable. The combination of trimethoprim/ sulphamethoxazole should not be recommended to treat pneumococcal infections, because of the high rate of resistant strains.
Result: Among the 100 isolates of Enterococcus from various clinical samples maximum isolates were from urine sample 70% and E. faecalis 92% constituted the predominant isolate. They were found to be susceptible to linezolid and vancomycin with least sensitive to ciprofloxacin and tetracycline. Conclusion: Routine speciation and in vitro antimicrobial susceptibility testing of Enterococcus in various clinical samples is emphasized due to the prevalence of wide variety of Enterococcus species and also appearance of high resistant strains. [Natl J Med Res 2013; 3(4.000: 389-391
Safavieh, Mohammadali; Pandya, Hardik J; Venkataraman, Maanasa; Thirumalaraju, Prudhvi; Kanakasabapathy, Manoj Kumar; Singh, Anupriya; Prabhakar, Devbalaji; Chug, Manjyot Kaur; Shafiee, Hadi
Rapid antimicrobial susceptibility testing is important for efficient and timely therapeutic decision making. Due to globally spread bacterial resistance, the efficacy of antibiotics is increasingly being impeded. Conventional antibiotic tests rely on bacterial culture, which is time-consuming and can lead to potentially inappropriate antibiotic prescription and up-front broad range of antibiotic use. There is an urgent need to develop point-of-care platform technologies to rapidly detect pathogens, identify the right antibiotics, and monitor mutations to help adjust therapy. Here, we report a biosensor for rapid (microchips with printed electrodes using antibodies (30 min), and its electrical response is monitored in the presence and absence of antibiotics over an hour of incubation time. We evaluated the microchip with Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA) as clinical models with ampicillin, ciprofloxacin, erythromycin, daptomycin, gentamicin, and methicillin antibiotics. The results are compared with the current standard methods, i.e. bacteria viability and conventional antibiogram assays. The technology presented here has the potential to provide precise and rapid bacteria screening and guidance in clinical therapies by identifying the correct antibiotics for pathogens.
Ter Laak, E A; Pijpers, A; Noordergraaf, J H; Schoevers, E C; Verheijden, J H
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.
Samuel C. Kim
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.
Arfatahery, Noushin; Davoodabadi, Abolfazl; Abedimohtasab, Taranehpeimaneh
Staphylococcus aureus is one of the most common causes of seafood-borne diseases worldwide, which are attributable to the contamination of food by preformed enterotoxins. In this study, a total of 206 (34.3%) Staphylococcus aureus strains were obtained from 600 fish and shrimp samples and were tested for their antimicrobial susceptibility. We assessed the prevalence of the genes responsible for the staphylococcal enterotoxins (SEA, SEB) and toxic shock syndrome toxin 1 (TSST-1) genes. The results indicated that 34% of aqua food samples were contaminated with S. aureus, and 23.8% of these isolates were mec-A-positive. Sixty-four percent of the strains isolated from contaminated seafood was enterotoxigenic S. aureus, and 28.2% of SEs were MRSA-positive. The most prevalent genotype was characterized by the presence of the sea gene (45.2%), followed by the seb gene (18.5%), and the tst gene encoding TSST-1 was found in eight strains (3.9%). Of the 206 S. aureus isolates, 189 strains (84.9%) were resistant to at least one antibiotic. Given the frequent outbreaks of enterotoxigenic MRSA, it is necessary to make revisions to mandatory programmes to facilitate improved hygiene practices during fishing, aquaculture, processing, and sales to prevent the contamination of fishery products in Iran. PMID:27694813
Padrão de susceptibilidade a antimicrobianos e perfil plasmidial em Salmonella Muenster isoladas de suínos e do ambiente de abatedouros Antimicrobial susceptibility pattern and plasmid profile in Salmonella Muenster isolated from swine and abattoir environment, Brazil
Norma S. Lázaro
Full Text Available Foram analisadas para a presença de plasmídios 38 amostras de Salmonella Muenster isoladas de suínos e do ambiente de abatedouros localizados no Estado do Rio de Janeiro, no período de março de 1991 a fevereiro de 1992. A seleção das amostras teve como orientação o perfil apresentado frente aos antimicrobianos estreptomicina, tetraciclina, sulfonamida e sulfametoxazol-trimetoprim, sendo analisadas 13 cepas resistentes a um ou mais antimicrobianos, 18 com grau intermediário e sete sensíveis. Plasmidios variando em tamanho de 1,2 Kb a 42 Kb foram detectados em 37 (97,36% das 38 amostras, correspondendo a 11 perfis distintos (P1 a P11, variando em número de 1 a 6 plasmidios por modelo. O número e diversidade de plasmidios foi maior que os marcos de resistência por cepa. O plasmidio de 2,85 Kb foi o mais freqüente, estando presente em 83,78% das 37 cepas; somente o de 7,95 Kb foi detectado nos dois abatedouros. Não houve paralelismo entre padrão de resistência e perfil plasmidial, onde um mesmo antibiotipo foi encontrado em vários perfis plasmidiais. Os resultados na presente investigação permitiram concluir que a caracterização de plasmidios constituiu-se uma ferramenta útil e simples no rastreamento epidemiológico deste sorovar.Thirty-eight strains of Salmonella Muenster, isolated from swine and the abattoir environment, in the State of Rio de Janeiro, Brazil, from March 1991 to February 1992, were analyzed for the presence of plasmids. The strains were selected according to their profile regarding the antimicrobials: streptomycin, tetracycline, sulphonamide and sulfametoxazole-trimethoprim. Thirteen strains were resistant to one or several antimicrobials, 18 with intermediate degree and seven were sensitive. Plasmids varying in size from 1.2 Kb to 42 Kb were detected in 37 (97.36% of the 38 samples, corresponding to 11 different profiles (P1- P11, varying from 1 to 6 plasmids per model. The number and plasmids diversity
Statistical analyses of correlation between fluconazole MICs for Candida spp. assessed by standard methods set forth by the European Committee on Antimicrobial Susceptibility Testing (E.Dis. 7.1) and CLSI (M27-A2).
Rodriguez-Tudela, J.L.; Donnelly, J.P.; Pfaller, M.A.; Chryssantou, E.; Warn, P.; Denning, D.W.; Espinel-Ingroff, A.; Barchiesi, F.; Cuenca-Estrella, M.
The European Committee on Antimicrobial Susceptibility Testing (EUCAST) Subcommittee on Antifungal Susceptibility Testing recently published a standard for determining the susceptibility of fermentative yeasts to antifungals. From the beginning, the EUCAST and its North American counterpart, the CLS
Full Text Available Neisseria gonorrhoeae is the second most sexually transmitted diseases agents in developing countries. Antimicrobial resistance strains have created serious health concern. The aim of this study was to determine the frequency of endocervical gonococcal infection and antimicrobial susceptibility of N. gonorrhoeae in Kashan, Iran.In this study, 294 endocervical swabs were collected from married women referred to the obstetrics and gynecology clinics in Kashan from December 2012 to May 2013. The samples were cultured in modified Thayer Martin in 37°C with 5-10% CO2 for 72 hours. Gram staining, oxidase, catalase and carbohydrate utilization tests were used to identify the isolated species. All isolates were tested for their susceptibilities to antimicrobials using the Kirby Bauer-disk diffusion techniques.N. gonorrhoeae was detected in 2.38% of studied cases (95% confidence interval [CI] 1.5-3.26%. All isolates were resistance to ceftriaxone, penicillin G, ciprofloxacin, cefepime, and two isolate (28.5% showed intermediate sensitivity to tetracycline.Continued monitoring of prevalence of N. gonorrhoeae is important for preventing the dissemination of this microorganism. The present study emphasizes the importance of surveillance of antimicrobial resistance of N. gonorrhoeae in order to manage the rate of resistant strains and to revise the treatment policies.
Full Text Available ABSTRACT This study was conducted to determine the antimicrobial susceptibility patterns among common pathogens in the intensive care units (ICUs of a university hospital in northwestern Iran. A retrospective study was done on laboratory records of patients with nosocomial infection who were admitted to five ICUs of Imam Reza Hospital during a 21-month period from March 2010 to January, 2012. A total number of 556 isolates from 328 patients were evaluated. The most common sites of infections included respiratory (51.7%, urinary (24.8%, and blood (10.4%. The most frequently isolated microorganisms were Enterobacter aerogenes (50.6% followed by Escherichia coli (16.7% and Pseudomonas aeruginosa (7.5%. Staphylococcus aureus was the most frequent pathogen among gram-positives (39.7%. The rate of methicillin-resistant Staphylococcus aureus (MRSA was 87.5%. Multidrug-resistant (MDR gram-negative bacteria were documented in 25.8% of Acinetobacter, 20% of Klebsiella, and 16.6% of Pseudomonas. The most active antimicrobials were vancomycin (93.5% followed by amikacin (71.5% and gentamicin (46%. The overall antibiotic susceptibility was as follows: 36% ciprofloxacin, 19% imipenem, 20% trimethoprim-sulfamethoxazole, 20.5% ceftazidime, and 12% ceftriaxone. Due to the high rate of antimicrobial resistance in the ICU setting, more surveillance and control of the use of antimicrobials is needed to combat infections.
Angell, Joseph W.; Clegg, Simon R.; Sullivan, Leigh E.; Duncan, Jennifer S.; Grove‐White, Dai H.; Carter, Stuart D.; Evans, Nicholas J.
Background Contagious ovine digital dermatitis (CODD) is an important cause of infectious lameness in sheep in the UK and Ireland and has a severe impact on the welfare of affected individuals. The three treponemal phylogroups Treponema medium/Treponema vincentii‐like, Treponema phagedenis‐like and Treponema pedis spirochaetes have been associated with clinical CODD lesions and are considered to be a necessary cause of disease. There are scant data on the antimicrobial susceptibility of the t...
Boutet, Philippe; Detilleux, Johann; Motkin, Michel; Deliege, M.; PIRAUX, E.; Depinois, A.; Debliquy, P.; Mainil, Jacques; Czaplicki, G.; Lekeux, Pierre
A comparison of somatic cell count and antimicrobial susceptibility of subclinical mastitis pathogens in organic and conventional dairy herds.Bovine subclinical mastitis is the most important disease affecting dairy cows. The fluctuating increase in somatic cell count (SCC) that occurs causes major economic losses in dairy industry. This comparative study between conventional and organic dairy herds was conducted in the aim to better characterize which consequences might have different manage...
Lucero-Estrada, Cecilia S M; Soria, José Miguel; Favier, Gabriela Isabel; Escudero, María Esther
Yersinia enterocolitica is a food-borne pathogen that causes gastroenteritis with occasional postinfection sequels. This study was aimed to determinate the pathogenic potential, antimicrobial susceptibility, and genomic relationships of Y. enterocolitica strains of different bioserotypes (B/O) isolated from foods and human samples in San Luis, Argentina. Strains obtained by culture were bioserotyped and characterized by phenotypic and genotypic virulence markers, antimicrobial susceptibility, and pulsed-field gel electrophoresis (PFGE). Yersinia enterocolitica was detected in 9.2% of 380 samples, with a distribution of 10.6% (30/284) for food products and 5.2% (5/96) for human samples. Regarding the pathogenic potential, B1A strains of different serotypes were virF(-) ail(-), of which 72.0% (13/18) were ystB(+) with virulence-related phenotypic characteristics. Among B2/O:9 isolates, 75.0% (9/12) exhibited the genotype virF(+) ail(+) ystB(-) along with phenotypic traits associated with virulence; the same genotype was observed in 80.0% (4/5) of B3/O:3 and B3/O:5 strains. By PFGE, it was possible to separate Y. enterocolitica biotypes into 4 clonal groups (A to D) with 23 genomic types, generating a discriminatory index of 0.96. All isolates were susceptible to antimicrobials used for clinical treatment. This study highlights the presence of pathogenic bioserotypes and the high genomic diversity of the Y. enterocolitica strains isolated in our region.
Sun, Wei; Weingarten, Rebecca A; Xu, Miao; Southall, Noel; Dai, Sheng; Shinn, Paul; Sanderson, Philip E; Williamson, Peter R; Frank, Karen M; Zheng, Wei
Current antimicrobial susceptibility testing has limited screening capability for identifying empirical antibiotic combinations to treat severe bacterial infections with multidrug-resistant (MDR) organisms. We developed a new antimicrobial susceptibility assay using automated ultra-high-throughput screen technology in combination with a simple bacterial growth assay. A rapid screening of 5170 approved drugs and other compounds identified 25 compounds with activities against MDR Klebsiella pneumoniae. To further improve the efficacy and reduce the effective drug concentrations, we applied a targeted drug combination approach that integrates drugs' clinical antimicrobial susceptibility breakpoints, achievable plasma concentrations, clinical toxicities and mechanisms of action to identify optimal drug combinations. Three sets of three-drug combinations were identified with broad-spectrum activities against 10 MDR clinical isolates including K. pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Citrobacter freundii, Enterobacter cloacae and Escherichia coli. Colistin-auranofin-ceftazidime and colistin-auranofin-rifabutin suppressed >80% growth of all 10 MDR strains; while rifabutin-colistin-imipenem inhibited >75% of these strains except two Acinetobacter baumannii isolates. The results demonstrate this new assay has potential as a real-time method to identify new drugs and effective drug combinations to combat severe clinical infections with MDR organisms.
Hamasuna, Ryoichi; Yasuda, Mitsuru; Ishikawa, Kiyohito; Uehara, Shinya; Hayami, Hiroshi; Takahashi, Satoshi; Matsumoto, Tetsuro; Yamamoto, Shingo; Minamitani, Shinichi; Watanabe, Akira; Iwata, Satoshi; Kaku, Mitsuo; Kadota, Junichi; Sunakawa, Keisuke; Sato, Junko; Hanaki, Hideaki; Tsukamoto, Taiji; Kiyota, Hiroshi; Egawa, Shin; Tanaka, Kazushi; Arakawa, Soichi; Fujisawa, Masato; Kumon, Hiromi; Kobayashi, Kanao; Matsubara, Akio; Naito, Seiji; Kuroiwa, Kentaro; Hirayama, Hideo; Narita, Harunori; Hosobe, Takahide; Ito, Shin; Ito, Kenji; Kawai, Shuichi; Ito, Masayasu; Chokyu, Hirofumi; Matsumura, Masaru; Yoshioka, Masaru; Uno, Satoshi; Monden, Koichi; Takayama, Kazuo; Kaji, Shinichi; Kawahara, Motoshi; Sumii, Toru; Kadena, Hitoshi; Yamaguchi, Takamasa; Maeda, Shinichi; Nishi, Shohei; Nishimura, Hirofumi; Shirane, Takeshi; Yoh, Mutsumasa; Akiyama, Kikuo; Imai, Toshio; Kano, Motonori
Worldwide, the most important concern in the treatment of sexually transmitted infections is the increase in antimicrobial resistant Neisseria gonorrhoeae strains including resistance to cephalosporins, penicillins, fluoroquinolones or macrolides. To investigate the trends of antimicrobial susceptibility among N. gonorrhoeae strains isolated from male patients with urethritis, a Japanese surveillance committee conducted the second nationwide surveillance study. Urethral discharge was collected from male patients with urethritis at 26 medical facilities from March 2012 to January 2013. Of the 151 specimens, 103 N. gonorrhoeae strains were tested for susceptibility to 20 antimicrobial agents. None of the strains was resistant to ceftriaxone, but the minimum inhibitory concentration (MIC) 90% of ceftriaxone increased to 0.125 μg/ml, and 11 (10.7%) strains were considered less susceptible with an MIC of 0.125 μg/ml. There were 11 strains resistant to cefixime, and the MICs of these strains were 0.5 μg/ml. The distributions of the MICs of fluoroquinolones, such as ciprofloxacin, levofloxacin and tosufloxacin, were bimodal. Sitafloxacin, a fluoroquinolone, showed strong activity against all strains, including strains resistant to other three fluoroquinolones, such as ciprofloxacin, levofloxacin and tosufloxacin. The azithromycin MICs in 2 strains were 1 μg/ml.
El Semary, Nermin Adel
The antimicrobial activity of lipophilic extracts of mat-forming Phormidium-like cyanobacterium isolated from Egypt was investigated under different phosphate concentrations. The antimicrobial profile changed with different phosphate levels indicating metabolic changes under stressful conditions. The fractions that resulted in highest antimicrobial activity from the three different phosphate concentrations were chosen for further analyses. The bioactive compounds were identified using chromatographic and spectroscopic techniques including UV, FTIR, GC-MS and proton-NMR. The chemical analyses indicated that the compound at standard phosphate concentration was eugenol whereas the bioactive compound at half phosphate concentration was 4-tert-butylcyclohexanol. The third bioactive compound at quarter phosphate concentration was octadecanoic acid. The eugenol is known for its antimicrobial as well as pain relief properties and can be used in many pharmaceutical preparations whereas the octadecanoic acid and cyclohexanol derivative are used in some antimicrobial pharmaceuticals. The study highlights the change in antimicrobial profile of bioactive compounds derived from cyanobacteria through manipulating the concentration of a key nutrient in growth medium. This strategy can be employed for mass production of these compounds and others for future biotechnological applications.
Wisselink, H.J.; Veldman, K.T.; Salmon, S.A.; Mevius, D.J.
The susceptibility of Streptococcus suis strains (n = 384) isolated from diseased pigs in seven European countries to 10 antimicrobial agents was determined. For that purpose a microbroth dilution method was used according to CLSI recommendations. The following antimicrobial agents were tested: ceft
Kommedal, Øyvind; Aasen, Johanne Lind; Lindemann, Paul Christoffer
Diagnostic testing of positive blood cultures is among the most critical tasks performed by clinical microbiology laboratories, and the total analysis time from sampling to results should be kept as short as possible. By providing identification of pelleted bacteria directly from positive blood-cultures, MALDI-TOF MS opens for relatively low-complex species-adjusted genetic susceptibility testing from the same bacterial pellet. In our lab routine, we prospectively evaluated a rapid in-house real-time PCR targeting the most common aminoglycoside and cephalosporin resistance genes in Escherichia coli and Klebsiella pneumoniae and measured time to preliminary susceptibility reporting for 138 samples. The results were compared to direct phenotypic susceptibility testing with interpretation after 6 h and overnight incubation respectively. Results from the genetic susceptibility testing were available for 69.5% (96/138) of the positive blood cultures within 24 h after sample collection. No phenotypic susceptibility results were available at this time. Compared to overnight direct susceptibility testing, the average time from sample collection to preliminary susceptibility reporting was reduced with 43%, from 45 h and 5 min to 25 h and 44 min, providing an earlier adjustment of antimicrobial therapy for 12 patients. Minor logistic adjustments have the potential to save yet another 4 h.
Yano, Yutaka; Hamano, Kaoru; Tsutsui, Isao; Aue-Umneoy, Dusit; Ban, Masatoshi; Satomi, Masataka
We aimed to document the risk of Aeromonas spp. in marine shrimp species cultured in inland low salinity ponds in Thailand. In 14 of 18 shrimp samples retrieved from inland grow-up ponds, Aeromonas spp. were detected at ranges from 4667 to 1,500,000 CFU/g body weight. The phylogenetic tree constructed with the gyrB and cpn60 concatenated sequences indicated that the 87 isolates consisted of Aeromonas veronii (70%), Aeromonas aquariorum (18%), Aeromonas caviae (7%), Aeromonas jandaei (2%), and Aeromonas schubertii (2%). The potential virulence of the isolates was examined by phenotypic and PCR assays. Hemolytic activity and the extracellular activity of lipase, DNase, and gelatinase were observed in most isolates (94-99%). PCR revealed the presence of 9 genes related to virulence in the 87 isolates: act (75%), aer (74%), alt (30%), ast (1%), ascV (34%), aexT (24%), fla (92%), ela (34%), and lip (24%). The susceptibility profiles to 14 antimicrobial agents of isolates were typical for the genus, but resistance to cefotaxime, a third-generation cephalosporin, and imipenem were found in two A. aquariorum and in three A. veronii isolates, respectively. These resistances were confirmed by determining minimum inhibitory concentrations. Our results indicate that the microbiological risk posed by Aeromonas should be considered for marine shrimp species that are cultured in low-salinity ponds. These shrimps may also be a vehicle for the transfer of different genotypes of Aeromonas and antibiotic-resistant determinants to regions worldwide through trade.
El Zowalaty, Mohamed E; Al Thani, Asmaa A; Webster, Thomas J; El Zowalaty, Ahmed E; Schweizer, Herbert P; Nasrallah, Gheyath K; Marei, Hany E; Ashour, Hossam M
Antimicrobial resistance is one of the most serious public health issues facing humans since the discovery of antimicrobial agents. The frequent, prolonged, and uncontrolled use of antimicrobial agents are major factors in the emergence of antimicrobial-resistant bacterial strains, including multidrug-resistant variants. Pseudomonas aeruginosa is a leading cause of nosocomial infections. The abundant data on the increased resistance to antipseudomonal agents support the need for global action. There is a paucity of new classes of antibiotics active against P. aeruginosa. Here, we discuss recent antibacterial resistance profiles and mechanisms of resistance by P. aeruginosa. We also review future potential methods for controlling antibiotic-resistant bacteria, such as phage therapy, nanotechnology and antipseudomonal vaccines.
Khatiwada, Janak; Fullerton, Marjorie; Davis, Shurrita; Williams, Leonard L
Shiga toxin-producing Escherichia coli (STEC) remains a major public health concern. Microbial resistance may be due to use of antimicrobial agents (AAs) as a growth promoter in food animals or overuse of AAs in humans. The objective of the current study was to determine the antimicrobial susceptibility patterns of STEC strains isolated from food, veterinary, and clinical sources against 14 AAs by using the spiral gradient endpoint method. One hundred ten isolates from three sources were characterized. Results of the current study showed that all strains were resistant to the folate pathway inhibiting AAs including tylosin tartrate (gradient minimum inhibitory concentration [GMIC] ranges from ≥180.00 to 256.00 μg/mL; end concentration [EC] ranges from ≥130.00 to 151.22 μg/mL; and tail-end concentration [TEC] ≥145.00 μg/mL). All the strains isolated from three sources were susceptible to the fluoroquinolone class of AAs (GMIC ranges from ≤1.00 to 64.30 μg/mL; EC ranges from ≤3.33 to 72.00 μg/mL; and TEC ranges from ≤12.13 to 45.00 μg/mL). Among the food isolates, less resistance was found within the aminoglycoside and amphenicol group (GMIC ≥256.00 μg/mL; EC=161.00 μg/mL). Eight strains were resistant to one to three, 44 strains were resistant to four to six, and two strains were resistant to seven or more AAs. All the clinical isolates (100%) were susceptible to the fluoroquinolones and gentamycin. Results also showed that antimicrobial resistance was observed between four and six AAs among the isolates. Some veterinary isolates were resistant to five AAs. Least AAs resistance was shown by 3.7% of isolates to gentamycin and 7.45% to chloramphenicol. This study showed an increasing trend of antimicrobial resistant strains of STEC, and we suggest that periodic surveillance of the antimicrobial susceptibility may be a useful measure to detect the antimicrobial resistant pathogens.
Komiyama, Edson Yukio; Samaranayake, Lakshman P.; Parahitiyawa, Nipuna B.; Balducci, Ivan
Enterococci are considered as transient constituent components of the oral microbiome that may cause a variety of oral and systemic infections. As there is sparse data on the oral enterococcal prevalence, we evaluated the Enterococcus spp. and their virulence attributes including antimicrobial resistance in a healthy Brazilian cohort. A total of 240 individuals in different age groups were studied (children 4–11 yrs, adolescents 12–17 yrs, young adults 18–29 yrs, adults 30–59 yrs, elderly over 60 yrs). Oral rinses were collected and isolates were identified by API 20 Strep and confirmed by 16S rDNA sequencing. E. faecalis isolates, in particular, were evaluated for virulence attributes such as their biofilm formation potential, and susceptibility to antimicrobials and an antiseptic, chlorhexidine gluconate. A total of 40 individuals (16.6%) and 10% children, 4% adolescents, 14% young adults, 30% adults, and 25% elderly carried oral enterococci. The oral enterococcal burden in adolescents was significantly lower than in the adults (p = 0.000) and elderly (p = 0.004). The proportion of carriers was higher among females (p = 0.001). E. faecalis was the most frequent isolate in all the age groups (p = 0.000), followed by E. durans and E. faecium. Whilst all the clinical isolates were able to form biofilms, only a proportion of them were able to produce lipase (92%), hemolysin (38%), and gelatinase (39%). Of all the isolates 53.8% were resistant to tetracycline, 12.3% to amoxicillin, 16.0% to ampicillin, 20.8% to chloramphenicol and 43.4% to erythromycin. None of the isolates were resistant to vancomycin. Our data suggest that in this Brazilian cohort the oral cavity may act as a significant reservoir of rather virulent and antibiotic resistant enterococci, with an increasing degree of carriage in the adults and elderly. Hence clinicians should be cognizant of this silent reservoir of virulent enterococci that may pose a particular threat of nosocomial infection
Faria-Ramos, I; Neves-Maia, J; Ricardo, E; Santos-Antunes, J; Silva, A T; Costa-de-Oliveira, S; Cantón, E; Rodrigues, A G; Pina-Vaz, C
This is the first Portuguese multicenter observational and descriptive study that provides insights on the species distribution and susceptibility profiles of yeast isolates from fungemia episodes. Ten district hospitals across Portugal contributed by collecting yeast isolates from blood cultures and answering questionnaires concerning patients' data during a 12-month period. Molecular identification of cryptic species of Candida parapsilosis and C. glabrata complex was performed. The susceptibility profile of each isolate, considering eight of the most often used antifungals, was determined. Both Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) protocols were applied. The incidence of 240 episodes of fungemia was 0.88/1,000 admissions. Fifteen different species were found, with C. albicans (40 %) being the most prevalent, followed by C. parapsilosis (23 %) and C. glabrata (13 %). Most isolates were recovered from patients admitted to surgical wards or intensive care units, with 57 % being males and 32 % aged between 41 and 60 years. For both the CLSI and EUCAST protocols, the overall susceptibility rates ranged from 74 to 97 % for echinocandins and from 84 to 98 % for azoles. Important resistance rate discrepancies between protocols were observed in C. albicans and C. glabrata for echinocandins and in C. parapsilosis and C. tropicalis for azoles. Death associated with fungemia occurred in 25 % of the cases, with more than half of C. glabrata infections being fatal. The great number of Candida non-albicans is noteworthy despite a relatively low antifungal resistance rate. Studies like this are essential in order to improve empirical treatment guidelines.
Full Text Available Aim of the Study: The present study was conducted to investigate antimicrobial susceptibility pattern of Klebsiella pneumoniae strains isolated from clinical specimens of Jordanian pediatric patients during a five year period from 2005-2009. A total of 1023 Klebsiella pneumoniae strains were isolated from clinical specimens and tested for their susceptibility to different antimicrobial drugs. Main findings: Overall, high susceptibility rate was recorded for ciprofloxacin (90.5%, followed by norfloxacin (84.8%, imipenem (69.9%, nalidixic acid (66.6%, and cefixime (63.9%. Low susceptibility rate was recorded for ampicillin (16.6%, followed by amoxicillin-clavulanic acid (22.5%, tobramycin (28.6%, amikacin (31.4%, cotrimoxazole (37.3%, and aztreonam (39.3%, Conclusion: most of β-lactam antibiotics as well as tobramycin, amikacin, cotrimoxazole, and aztreonam, should not be used in treating infections caused by pathogenic K. pneumoniae and other related bacteria in Jordan. However, quinolone compounds and imipenem seem to be effective in treatment of infections caused by pathogenic K. pneumoniae in children.
Full Text Available The bacteria of the Bacteroides fragilis group are considered important clinical pathogens and they are the most common anaerobes isolated from human endogenous infections. In this study, the susceptibility patterns to antibiotics and metals of 114 species of the B. fragilis group isolated from children with and without diarrhea were determined. Susceptibility was assayed by using an agar dilution method with Wilkins-Chalgren agar. All B. fragilis strains were resistant to lead and nickel, but susceptible to metronidazole and imipenem. beta-lactamase production was detected by using biological and nitrocefin methods, respectively, in 50% and 90.6% of the isolates of children with diarrhea and in 60% and 90% of the isolates of children without diarrhea. Our results show an increase of antibiotics and metals resistance in this microbial group, and a periodic evaluation of the antimicrobial susceptibility is needed. In Brazil, the contamination for antibiotics or metal ions is often observed, and it is suggested an increase the antimicrobial resistance surveillance of this microbial group, mainly those isolated from children's diarrhea.
Ruiz-Rodríguez, Magdalena; Valdivia, Eva; Martín-Vivaldi, Manuel; Martín-Platero, Antonio M.; Martínez-Bueno, Manuel; Méndez, María; Peralta-Sánchez, Juan M.; Soler, Juan J.
Symbiotic microorganisms may be directly transferred from parents to offspring or acquired from a particular environment that animals may be able to select. If benefits for hosts vary among microbial strains, natural selection may favour hosts holding the most beneficial one. Enterococci symbionts living in the hoopoe (Upupa epops) uropygial gland are able to synthesise bacteriocins (antimicrobial peptides that inhibit the growth of competitor bacteria). We explored variability in genetic profile (through RAPD-PCR analyses) and antimicrobial properties (by performing antagonistic tests against ten bacterial indicator strains) of the different isolates obtained from the uropygial glands of hoopoe females and nestlings. We found that the genetic profile of bacterial isolates was related to antimicrobial activity, as well as to individual host identity and the nest from which samples were obtained. This association suggest that variation in the inhibitory capacity of Enterococci symbionts should be under selection. PMID:22911858
Ruiz-Rodríguez, Magdalena; Valdivia, Eva; Martín-Vivaldi, Manuel; Martín-Platero, Antonio M; Martínez-Bueno, Manuel; Méndez, María; Peralta-Sánchez, Juan M; Soler, Juan J
Symbiotic microorganisms may be directly transferred from parents to offspring or acquired from a particular environment that animals may be able to select. If benefits for hosts vary among microbial strains, natural selection may favour hosts holding the most beneficial one. Enterococci symbionts living in the hoopoe (Upupa epops) uropygial gland are able to synthesise bacteriocins (antimicrobial peptides that inhibit the growth of competitor bacteria). We explored variability in genetic profile (through RAPD-PCR analyses) and antimicrobial properties (by performing antagonistic tests against ten bacterial indicator strains) of the different isolates obtained from the uropygial glands of hoopoe females and nestlings. We found that the genetic profile of bacterial isolates was related to antimicrobial activity, as well as to individual host identity and the nest from which samples were obtained. This association suggest that variation in the inhibitory capacity of Enterococci symbionts should be under selection.
Full Text Available Symbiotic microorganisms may be directly transferred from parents to offspring or acquired from a particular environment that animals may be able to select. If benefits for hosts vary among microbial strains, natural selection may favour hosts holding the most beneficial one. Enterococci symbionts living in the hoopoe (Upupa epops uropygial gland are able to synthesise bacteriocins (antimicrobial peptides that inhibit the growth of competitor bacteria. We explored variability in genetic profile (through RAPD-PCR analyses and antimicrobial properties (by performing antagonistic tests against ten bacterial indicator strains of the different isolates obtained from the uropygial glands of hoopoe females and nestlings. We found that the genetic profile of bacterial isolates was related to antimicrobial activity, as well as to individual host identity and the nest from which samples were obtained. This association suggest that variation in the inhibitory capacity of Enterococci symbionts should be under selection.
Full Text Available Abstract Background Knowledge on antimicrobial drug resistance and genetic characteristics of Neisseria gonorrhoeae isolates circulating in India, Pakistan, and Bhutan is sorely lacking. In this paper, we describe the prevalence of antimicrobial resistance and molecular characteristics of N. gonorrhoeae isolates from India, Pakistan, and Bhutan in 2007–2011. Methods Antimicrobial susceptibility and β-lactamase production were tested for 65 N. gonorrhoeae isolates from India (n=40, Pakistan (n=18 and Bhutan (n=7 using Etest methodology (eight antimicrobials and nitrocefin solution, respectively. Resistance determinants, i.e. penA, mtrR, porB1b, gyrA, and parC, were sequenced. N. gonorrhoeae multiantigen sequence typing (NG-MAST was performed for molecular epidemiology. Results The highest resistance level was observed for ciprofloxacin (94%, followed by penicillin G (68%, erythromycin (62%, tetracycline (55%, and azithromycin (7.7%. All the isolates were susceptible to ceftriaxone, cefixime, and spectinomycin. Thirty-four (52% of the isolates were producing β-lactamase. No penA mosaic alleles or A501-altered alleles of penicillin-binding protein 2 were identified. Forty-nine NG-MAST STs were identified, of which 42 STs have not been previously described worldwide. Conclusions Based on this study, ceftriaxone, cefixime, and spectinomycin can be used as an empirical first-line therapy for gonorrhoea in India, Pakistan, and Bhutan, whereas ciprofloxacin, penicillin G, tetracycline, erythromycin, and azithromycin should not be. It is imperative to strengthen the laboratory infrastructure in this region, as well as to expand the phenotypic and genetic surveillance of antimicrobial resistance, emergence of new resistance, particularly, to extended-spectrum cephalosporins, and molecular epidemiology.
Tchesnokova, Veronika; Avagyan, Hovhannes; Billig, Mariya; Chattopadhyay, Sujay; Aprikian, Pavel; Chan, Diana; Pseunova, Julietta; Rechkina, Elena; Riddell, Kim; Scholes, Delia; Fang, Ferric C.; Johnson, James R.; Sokurenko, Evgeni V.
Background. Escherichia coli is a highly clonal pathogen. Extraintestinal isolates belong to a limited number of genetically related groups, which often exhibit characteristic antimicrobial resistance profiles. Methods. We developed a rapid clonotyping method for extraintestinal E coli based on detection of the presence or absence of 7 single nucleotide polymorphisms (SNPs) within 2 genes (fumC and fimH). A reference set of 2559 E coli isolates, primarily of urinary origin, was used to predict the resolving power of the 7-SNP-based typing method, and 582 representative strains from this set were used to evaluate test robustness. Results. Fifty-four unique SNP combinations (“septatypes”) were identified in the reference strains. These septatypes yielded a clonal group resolution power on par with that of traditional multilocus sequence typing. In 72% of isolates, septatype identity predicted sequence type identity with at least 90% (mean, 97%) accuracy. Most septatypes exhibited highly distinctive antimicrobial susceptibility profiles. The 7-SNP-based test could be performed with high specificity and sensitivity using single or multiplex conventional polymerase chain reaction (PCR) and quantitative PCR. In the latter format, E coli presence and septatype identity were determined directly in urine specimens within 45 minutes with bacterial loads as low as 102 colony-forming units/mL and, at clinically significant bacterial loads, with 100% sensitivity and specificity. Conclusions. 7-SNP-based typing of E coli can be used for both epidemiological studies and clinical diagnostics, which could greatly improve the empirical selection of antimicrobial therapy. PMID:26925427
Rasmussen, S. R.; Aarestrup, Frank Møller; Jensen, N. E.
A total of 122 Streptococcus suis serotype 2 strains were characterized thoroughly by comparing clinical and pathological observations, ribotype profiles, and antimicrobial resistance. Twenty-one different ribotype profiles were found and compared by cluster analysis, resulting in the identificat......A total of 122 Streptococcus suis serotype 2 strains were characterized thoroughly by comparing clinical and pathological observations, ribotype profiles, and antimicrobial resistance. Twenty-one different ribotype profiles were found and compared by cluster analysis, resulting...... ribotypes were almost exclusively isolated from pigs with meningitis, while strains of the other dominant ribotype were never associated with meningitis. This second ribotype was isolated only from pigs with pneumonia, endocarditis, pericarditis, or septicemia. Cluster analysis revealed that strains...... of resistance to antibiotics because strains isolated from pigs with meningitis were resistant to sulfamethazoxazole and strains isolated from pigs with pneumonia, endocarditis, pericarditis, or septicemia were resist-ant to tetracycline....
Lyskova, P; Vydrzalova, M; Mazurova, J
The bacterial and fungal flora of the external ear canal of dogs with otitis externa and of healthy dogs were studied. The most frequently isolated microorganism from otitic ears was Staphylococcus intermedius (58.8%), followed by Malassezia pachydermatis (30.9%), Streptococcus canis (29.9%), Proteus spp. (14.4%) and Escherichia coli (10.3%). A statistical analysis of our results showed that the prevalence of these microorganisms is significant in dogs with otitis externa. Furthermore, the antimicrobial susceptibility patterns of isolated strains were determined. Majority of all bacterial isolates were most susceptible to gentamicin. Malassezia pachydermatis, the most prevalent yeast in this study, showed an excellent level of susceptibility to all antifungal agents tested.
Full Text Available Out of the 5933 samples collected a total of 51 isolates of pseudomonas aeruginosa were collected consecutively between 26-December-2010 to 28-February-2011 from different patients. The total of 51 positive isolates consists both of pediatric as well as adult patients. The study was therefore carried out using bothmanual (Kirby-Bauer method as well as automated (Vitek2 system method to determine the Antimicrobial susceptibility pattern of pseudomonas aeruginosa isolates from in-patients and out-patients attending the microbiology section of the hospitals. The isolation rate of Pseudomonas aeruginosa was found to be 8.5% out of the total positive samples which were analyzed. In my study, notable sensitivity (100% to P.aeruginosa was observed against Aztreonam while it was found to be different in case of a study carried out in India earlier which observed Carbepenems with 19.40% resistance. In the study colistin showed the highest (100% sensitivity followed by Amikacin against P. aeruginosa , which is in corroboration with an earlier report published from India. Amikacin seems to be a promising therapy for Pseudomonal infection. Hence, its use should be restricted to severe nosocomial infections, in order to avoid rapid emergence of resistant strains. The sensitivity of Pseudomonas aeruginosa towards Imipenem is found to be 35.294% and towards Meropenem is 41.176%, which is different in case of the earlier study from India. An effective national and state level antibiotic policy and draft guidelines should be introduced to preserve the effectiveness of antibiotics and for better patient management.
Full Text Available Introduction: Pneumococcal infections are important cause of morbidity and mortality. Knowledge of antimicrobial susceptibility patterns plays important role in the selection of appropriate therapy. Present study was undertaken to analyze the susceptibility patterns of pneumococcal isolates against commonly used antimicrobials with special reference to determination of minimum inhibitory concentration (MIC of penicillin in a tertiary care hospital in eastern Nepal. Methods: Twenty-six strains of S. pneumoniae isolated from various clinical specimens submitted to microbiology laboratory were evaluated. All isolates were tested for antimicrobial susceptibility by disk diffusion method. MIC of penicillin was tested by broth dilution method. Results: Of the total isolates 19 (73% were from invasive infections. Seven isolates were resistant to cotrimoxazole. No resistance to penicillin was seen in disk diffusion testing. Less susceptibility to penicillin (MIC 0.1-1.0 mg/L was observed in five (17% isolates. High level resistance to penicillin was not detected. One isolate was multidrug resistant. Conclusions: S. pneumoniaeisolates with intermediate resistance to penicillin prevail in Tertiary Care Hospital in eastern Nepal, causing invasive and noninvasive infections. As intermediate resistance is not detected in routine susceptibility testing, determination of MIC is important. It helps not only in the effective management of life threatening infections but is also essential in continuous monitoring and early detection of resistance. In addition, further study on pneumococcal infections, its antimicrobial resistance profile and correlation with clinical and epidemiological features including serotypes and group prevalence is recommended in future. Keywords: antimicrobial susceptibility pattern, penicillin, Streptococcus pneumoniae.
Forbes, Sarah; Latimer, Joe; Bazaid, Abdulrahman; McBain, Andrew J
Staphylococcus aureus can produce small-colony variants (SCVs) that express various phenotypes. While their significance is unclear, SCV propagation may be influenced by relative fitness, antimicrobial susceptibility, and the underlying mechanism. We have investigated triclosan-induced generation of SCVs in six S. aureus strains, including methicillin-resistant S. aureus (MRSA). Parent strains (P0) were repeatedly passaged on concentration gradients of triclosan using a solid-state exposure system to generate P10. P10 was subsequently passaged without triclosan to generate X10. Susceptibility to triclosan and 7 antibiotics was assessed at all stages. For S. aureus ATCC 6538, SCVs were further characterized by determining microbicide susceptibility and competitive fitness. Cellular morphology was examined using electron microscopy, and protein expression was evaluated through proteomics. Triclosan susceptibility in all SCVs (which could be generated from 4/6 strains) was markedly decreased, while antibiotic susceptibility was significantly increased in the majority of cases. An SCV of S. aureus ATCC 6538 exhibited significantly increased susceptibility to all tested microbicides. Cross-wall formation was impaired in this bacterium, while expression of FabI, a target of triclosan, and IsaA, a lytic transglycosylase involved in cell division, was increased. The P10 SCV was 49% less fit than P0. In summary, triclosan exposure of S. aureus produced SCVs in 4/6 test bacteria, with decreased triclosan susceptibility but with generally increased antibiotic susceptibility. An SCV derived from S. aureus ATCC 6538 showed reduced competitive fitness, potentially due to impaired cell division. In this SCV, increased FabI expression could account for reduced triclosan susceptibility, while IsaA may be upregulated in response to cell division defects.
Full Text Available Introduction. In Gram-negative bacteria, the production of beta-lactamases is the most important mechanism of resistance to beta-lactam antibiotics. In the Banja Luka region, there were no extensive researches on the prevalence and antimicrobial resistance of the extended-spectrum beta-lactamase (ESBL producing Escherichia coli (E. coli isolates. Objective. The aim of the present study was to determine the presence of ESBL producing E. coli isolates as the cause of the urinary tract infections in outpatients, the distribution of these ESBL isolates according to age and gender of patients and their susceptibility to antimicrobials. Methods. Urine specimens obtained from outpatients were cultured on chromogenic CPS-ID3 media. All plates showing significant (>105 cfu/ml growth of E. coli in pure culture were further processed. Antimicrobial susceptibility testing was performed on VITEK TWO Compact using AST-GN27 cards for testing Gram negative bacteria and detection of ESBL producers. Results. Out of 2,195 isolates, 177 (8.1% were ESBL producers. Ninety-two isolates were obtained from female patients (5% of E. coli isolated from women and 85 isolates from male patients (23% of E. coli isolated from men. High percentage of ESBL isolates was detected in the infant age group under one year (36.7% and in the age group over 60 years (28.8%. All ESBL isolates were susceptible to imipenem and resistant to ampicillin, piperacillin, cefazolin, cefotaxime, ceftazidime and cefepime. There was a significant resistance to amikacin (79.1%, gentamicin (76.8%, amoxicillin/clavulanate (54.8% and trimethoprim/sulphamethoxazole (45.8%. Resistance to nutrofurantoin was 13.6%. Conclusion. This study has demonstrated the presence of ESBL producing E. coli urinary isolates in outpatients, and their extensive susceptibility to imipenem and nitrofurantoin.
Zhang Hui; Yang Qiwen; Xiao Meng; Chen Minjun; Robert E.Badal; Xu Yingchun
Background The Study for Monitoring Antimicrobial Resistance Trends program monitors the activity of antibiotics against aerobic and facultative Gram-negative bacilli (GNBs) from intra-abdominal infections (IAIs) in patients worldwide.Methods In 2011,1 929 aerobic and facultative GNBs from 21 hospitals in 16 cities in China were collected.All isolates were tested using a panel of 12 antimicrobial agents,and susceptibility was determined following the Clinical Laboratory Standards Institute guidelines.Results Among the Gram-negative pathogens causing IAIs,Escherichia coli (47.3％) was the most commonly isolated,followed by Klebsiella pneumoniae (17.2％),Pseudomonas aeruginosa (10.1％),and Acinetobacter baumannii (8.3％).Enterobacteriaceae comprised 78.8％ (1521/1929) of the total isolates.Among the antimicrobial agents tested,ertapenem and imipenem were the most active agents against Enterobacteriaceae,with susceptibility rates of 95.1％ and 94.4％,followed by amikacin (93.9％) and piperacillin/tazobactam (87.7％).Susceptibility rates of ceftriaxone,cefotaxime,ceftazidime,and cefepime against Enterobacteriaceae were 38.3％,38.3％,61.1％,and 50.8％,respectively.The leastactive agent against Enterobacteriaceae was ampicillin/sulbactam (25.9％).The extended-spectrum β-lactamase (ESBL) rates among E.coli,K.pneumoniae,Klebsiella oxytoca,and Proteus mirabilis were 68.8％,38.1％,41.2％,and 57.7％,respectively.Conclusions Enterobacteriaceae were the major pathogens causing IAIs,and the most active agents against the study isolates (including those producing ESBLs) were ertapenem,imipenem,and amikacin.Including the carbapenems,most agents exhibited reduced susceptibility against ESBL-positive and multidrug-resistant isolates.
Drake, M; Amadi, V; Zieger, U; Johnson, R; Hariharan, H
Cloacal swabs and caecal contents sampled from 58 cane toads (Bufo marinus) in St George's parish, Grenada, during a 7-month period in 2011 were examined by an enrichment and selective culture method for presence of Salmonella spp. Twenty-four (41%) toads were positive for Salmonella spp. of which eight were Salmonella enterica serovar Javiana, and eight were S. enterica serovar Rubislaw. The other serovars were as follows: Montevideo, 6; Arechavaleta, 1; and serovar: IV:43:-:-, 1. The high frequency of isolation of serovar Javiana, an emerging human pathogen associated with several outbreaks in the recent years in the eastern United States, suggests a possible role for cane toads in transmission of this serovar. Although S. Rubislaw has been isolated from lizards, bats and cases of some human infections, there is no report of its carriage by cane toads, and in such high frequency. The rate of carriage of S. Montevideo, a cause for human foodborne outbreaks around the world was also over 10% in the 58 toads sampled in this study. The antimicrobial drug susceptibility tests against amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, imipenem, nalidixic acid, streptomycin, tetracycline and trimethoprim-sulfamethoxazole showed that drug resistance is minimal and is of little concern. Antimicrobial resistance was limited to ampicillin and amoxicillin-clavulanic acid in one isolate of S. Javiana and one isolate of S. Rubislaw. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars not identified previously in cane toads in Grenada, West Indies.
El-Nawawy, Ahmed A; Hafez, Soad F; Meheissen, Marwa A; Shahtout, Nehal M; Mohammed, Essam E
Streptococcus pneumoniae is a major cause of childhood morbidity and mortality worldwide with increasing antimicrobial resistance. 600 randomly chosen asymptomatic healthy children aged 2-60 months attending Alexandria University Children's Hospital were evaluated for prevalence of nasopharyngeal (NP) carriage of S. pneumoniae. Prevalence of NP carriage was 29.2% (n = 175/600) Capsular serotyping was done using Quellung reaction. Vaccine covered serotypes (VST) represented 67.4% while non-vaccine serotypes (NVST) were 32.6%. The most common VST isolated were 19F (24.6%), 6B (14.3%) and 6A (10.9%). Confirmation of serotyping was performed by multiplex PCR which showed 100% concordance with the Quellung reaction. Antimicrobial susceptibility testing showed penicillin non-susceptibility of 15% (using non-meningitis penicillin MIC breakpoints) and 55% (using meningitis penicillin MIC breakpoints). Highest resistance was found in sulphamethoxazole-trimethoprim (55%), tetracyclins (49%), erythromycin (40%) and clindamycin (25%). This study revealed the epidemiological importance to evaluate regularly the prevalence, serotypes and the increasing antimicrobial resistance of S. pneumoniae in the community.
Derbie, Awoke; Adem, Yesuf; Biadglegne, Fantahun
Background. Urinary tract infection is a major health problem especially in developing countries. Information about bacterial pathogens isolated from urinary tract infection in diabetic patients and their antimicrobial susceptibility patterns is limited in Ethiopia. Therefore, this study aimed at isolating bacterial pathogens and their antimicrobial susceptibility patterns. Methods. A hospital based comparative cross-sectional study was conducted at Debre Tabor. Urine sample was inoculated onto cysteine lysine electrolyte deficient (CLED) medium. Bacterial pathogens were identified using standard bacteriological methods. The data were cleaned and entered into SPSS version 20. P value less than 0.05 is considered statistically significant. Result. A total of 384 study participants were included in the study. Of them, 21 (10.9%) were from diabetics and 9 (4.7%) of them were from nondiabetics. Large proportion of gram positive bacteria at 18 (58.1%) were isolated compared to gram negatives at 13 (41.9%). Gram positive isolates were resistant to cotrimoxazole 10 (58.8%). Conclusion. The isolation rates of bacterial pathogens were higher in diabetic than nondiabetic patients. Bacteriuria was significantly associated with sex and type of diabetes. Multidrug resistance to two or more antibiotics was observed in 56.7% of bacterial isolates. Rational use of antimicrobial agent should be thought of to prevent the emergence of multidrug resistance.
Full Text Available Neonatal sepsis is one of the most common causes of neonatal mortality and morbidity, particularly in the developing countries. Appropriate clinical diagnosis and empirical treatment is crucial as pathogens causing sepsis and their antibiotic susceptibility pattern varies in different settings. The objective of this study was to determine the causative bacteria and pattern of susceptibility to antibiotics in NICU, which in turn may help in implementation of empirical therapy. MATERIALS AND METHOD A total of 100 blood samples were screened for sepsis in newborns less than 28 days old in this prospective study. The blood cultures of suspected cases were detected by using BACTEC blood culture systems and antibiotic susceptibility testing was done by using Kirby-Bauer disk diffusion method. This prospective observational study was conducted in the Department of Microbiology and Level III NICU in the Department of Paediatrics of D. Y. Patil Hospital and Research Centre during the period of two years 2013 to 2015. RESULTS In this study out of 100 neonates 38 (38% showed sepsis and 62 (62% showed no sepsis. Most common organisms responsible for the sepsis were CONS followed by Klebsiella pneumonia and Acinetobacter sp. Gram negative organisms were 100% sensitive to Colistin, Imipenem and Meropenem while Gram positive organisms were 100% sensitive to Azithromycin, Linezolid and Vancomycin. CONCLUSION The diagnostic capabilities of blood culture systems have improved over the last decade with the advent of automated continuous blood culture monitoring systems. BACTEC is a sensitive method and lead to earlier detection of bacterial growth
Weinstein, Melvin P; Klugman, Keith P; Jones, Ronald N
In January 2008, the Clinical and Laboratory Standards Institute published revised susceptibility breakpoints for penicillin and Streptococcus pneumoniae, and shortly thereafter, the United States Food and Drug Administration similarly revised its breakpoints via changes in the package insert for penicillin. The revised susceptibility breakpoint is penicillin at a dosage of 12 million units-24 million units per day. The susceptibility breakpoint of penicillin at a dosage of > or =18 million units per day. Herein, we review the scientific basis for the revisions to the breakpoints, which were supported by microbiologic, pharmacokinetic and/or pharmacodynamic, and clinical data. Clinicians, once again, should feel comfortable prescribing penicillin for pneumococcal pneumonia and other pneumococcal infections outside the central nervous system.
Afema, J A; Mather, A E; Sischo, W M
Analysis of long-term anti-microbial resistance (AMR) data is useful to understand source and transmission dynamics of AMR. We analysed 5124 human clinical isolates from Washington State Department of Health, 391 cattle clinical isolates from the Washington Animal Disease Diagnostic Laboratory and 1864 non-clinical isolates from foodborne disease research on dairies in the Pacific Northwest. Isolates were assigned profiles based on phenotypic resistance to 11 anti-microbials belonging to eight classes. Salmonella Typhimurium (ST), Salmonella Newport (SN) and Salmonella Montevideo (SM) were the most common serovars in both humans and cattle. Multinomial logistic regression showed ST and SN from cattle had greater probability of resistance to multiple classes of anti-microbials than ST and SN from humans (P Salmonella may be due to greater diversity of sources entering the human population compared to cattle or due to continuous evolution in the human environment. Also, AMR diversity was greater in clinical compared to non-clinical cattle Salmonella, and this could be due to anti-microbial selection pressure in diseased cattle that received treatment. The use of bootstrapping techniques showed that although there were shared profiles between humans and cattle, the expected and observed number of profiles was different, suggesting Salmonella and associated resistance from humans and cattle may not be wholly derived from a common population.
Sylvester, W R B; Amadi, V; Pinckney, R; Macpherson, C N L; McKibben, J S; Bruhl-Day, R; Johnson, R; Hariharan, H
Cloacal swabs from 62 green iguanas (Iguana iguana), including 47 wild and 15 domestic ones from five parishes of Grenada, were sampled during a 4-month period of January to April 2013 and examined by enrichment and selective culture for the presence of Salmonella spp. Fifty-five per cent of the animals were positive, and eight serovars of Salmonella were isolated. The most common serovar was Rubislaw (58.8%), a serovar found recently in many cane toads in Grenada, followed by Oranienburg (14.7%), a serovar that has been causing serious human disease outbreaks in Japan. Serovar IV:48:g,z51 :- (formerly, S. Marina) highly invasive and known for serious infections in children in the United States, constituted 11.8% of the isolates, all of them being from domestic green iguanas. Salmonella Newport, a serovar recently found in a blue land crab in Grenada, comprised 11.8% of the isolates from the green iguanas. The remaining four less frequent serovars included S. Javiana and S. Glostrup. Antimicrobial susceptibility tests conducted by a disc diffusion method against amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, streptomycin, tetracycline and trimethoprim-sulfamethoxazole showed that drug resistance is minimal, with intermediate susceptibility, mainly to streptomycin, tetracycline and cefotaxime. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars from wild and domestic green iguanas in Grenada, West Indies.
Stošić, Milena; Čučak, Dragana; Kovačević, Srđan; Perović, Marija; Radonić, Jelena; Turk Sekulić, Maja; Vojinović Miloradov, Mirjana; Radnović, Dragan
Wastewater from meat processing industries is a fusion of compounds with a high load of organic matter, and pathogen microorganisms like Escherichia coli, and Salmonella sp. The aim of this research was to determine microbiological characteristics of the wastewater discharged from the meat processing industry in order to get a more detailed insight into meat industry wastewater pollution, and to evaluate the resistance of bacterial strains E. coli and Salmonella sp. to antibiotics. The evaluation of the antimicrobial susceptibility was performed on 37 strains of E. coli and eight strains of Salmonella sp. to nine different antibiotics. The number of faecal pollution indicators was very high in all samples. From a total of 37 strains of E. coli, a moderate degree of resistance was shown to tetracycline (37.83%); a low degree of resistance to ampicillin (21.62%), streptomycin (24.32%), trimethoprim-sulfamethoxazol (18.92%) and nalidixic acid (16.22%); and very low to: chloramphenicol (13.51%), ciprofloxacin (2.7%), gentamicin and cefotaxime (0.0%). The results for eight strains of Salmonella sp. show that all eight isolates had some degree of susceptibility to nine tested antimicrobial agents and six strains were fully susceptible to all tested antibiotics.
Moradi Bidhendi, S
Full Text Available Salmonellosis is a very important disease of avian species because of its huge economic impact, worldwide distribution and difficulty posed in its control. Fowl typhoid and pullorum disease, is caused by Salmonella enterica subsp enterica serovar Gallinarum biovar Gallinarum and Pullorum. The purpose of this study was to investigate the biochemical characteristics and antimicrobial susceptibility of Salmonella gallinarum and Salmonella pullorum. A total of 13 Salmonella isolates, identified by biochemical tests and specific antisera including Salmonella gallinarum (n=10 and Salmonella pullorum (n=3. All were found to be susceptible to gentamicin. Also 7 (53.8 %, 6 (46.1% and 5 (38.4% isolates were resistant to streptomycin, cephalexin and nalidixic acid respectively. Multidrug resistance to three or more antibiotics was observed in 6 (46.1% isolates and overall 9 antibiotic resistance patterns were recorded. The results showed that poultries as a source of antimicrobial resistance could pose a serious risk to public health via food chain transfer. Hence more epidemiological surveillance programs and antibiotic susceptibility investigations are advised.
de Jong, Anno; Thomas, Valérie; Simjee, Shabbir; Moyaert, Hilde; El Garch, Farid; Maher, Kirsty; Morrissey, Ian; Butty, Pascal; Klein, Ulrich; Marion, Hervé; Rigaut, Delphine; Vallé, Michel
VetPath is an ongoing pan-European antibiotic susceptibility monitoring programme collecting pathogens from diseased antimicrobial non-treated cattle, pigs and poultry. In the current study, 1001 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 11 countries during 2002-2006. Pasteurella multocida and Mannheimia haemolytica from cattle and P. multocida, Actinobacillus pleuropneumoniae and Streptococcus suis from pigs were isolated by standard methods. S. suis was also isolated from meningitis cases. MICs of 16 antibiotics were assessed centrally by broth microdilution following CLSI recommendations. Results were interpreted using CLSI breakpoints where available. P. multocida (231) and M. haemolytica (138) isolates were all susceptible to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin and trimethoprim/sulfamethoxazole. Resistance to florfenicol and spectinomycin was 0.4% and 3.5% in P. multocida, respectively, and absent in M. haemolytica isolates. Tetracycline resistance was 5.7% and 14.6% for P. multocida and M. haemolytica. In pigs, 230 P. multocida, 220 A. pleuropneumoniae and 182 S. suis isolates were recovered. Resistance to amoxicillin/clavulanic acid, ceftiofur, enrofloxacin, florfenicol, tiamulin and tilmicosin was absent or cattle and pigs. Since for approximately half of the antibiotics in this panel no CLSI-defined breakpoints were available, setting of the missing veterinary breakpoints is important.
Vieira, Cristina Dutra; de Carvalho, Maria Auxiliadora Roque; Cussiol, Noil Amorim de Menezes; Alvarez-Leite, Maria Eugênia; dos Santos, Simone Gonçalves; Gomes, Renata Maria da Fonseca; Silva, Marcos Xavier; Nicoli, Jacques Robert; Farias, Luiz de Macêdo
In Brazil, few studies on microbial content of dental solid waste and its antibiotic susceptibility are available. An effort has been made through this study to evaluate the hazardous status of dental solid waste, keeping in mind its possible role in cross-infection chain. Six samples of solid waste were collected at different times and seasons from three dental health services. The microbial content was evaluated in different culture media and atmospheric conditions, and the isolates were submitted to antibiotic susceptibility testing. A total of 766 bacterial strains were isolated and identified during the study period. Gram-positive cocci were the most frequent morphotype isolated (48.0%), followed by Gram-negative rods (46.2%), Gram-positive rods (5.0%), Gram-negative-cocci (0.4%), and Gram-positive coccobacillus (0.1%). Only two anaerobic bacteria were isolated (0.3%). The most frequently isolated species was Staphylococcus epidermidis (29.9%), followed by Stenotrophomonas maltophilia (8.2%), and Enterococcus faecalis (6.7%). High resistance rate to ampicillin was observed among Gram-negative rods (59.4%) and Gram-positive cocci (44.4%). For Gram-negative rods, high resistance was also noted to aztreonam (47.7%), cefotaxime (47.4%), ceftriaxone and cefazolin (43.7%), and ticarcillin-clavulanic acid (38.2%). Against Gram-positive cocci penicillin exhibit a higher resistance rate (45.0%), followed by ampicillin, erythromycin (27.2%), and tetracycline (22.0%). The present study demonstrated that several pathogenic bacteria are present in dental solid waste and can survive after 48 h from the waste generation time and harbor resistance profiles against several clinical recommended antibiotics.
Full Text Available Background: Contamination of water, food, and environment with antibiotic-resistant bacteria poses a serious public health issue. Objective: The objective was to study the bacterial pollution of the natural sources of water in east Sikkim and to determine the antimicrobial profile of the bacterial isolates. Materials and Methods: A total of 225 samples, 75 each during winter, summer, and monsoon season were collected from the same source in every season for bacteriological analysis by membrane filtration method. Antibiotic susceptibility test was performed using standard disc diffusion method. Results: A total of 19 bacterial species of the genera Escherichia, Klebsiella, Proteus, Salmonella, Shigella, Enterobacter, Citrobacter, Morganella, Pseudomonas, Acinetobacter, Flavobacterium, and Serratia were isolated and their antimicrobial sensitivity tested. Generally, most bacterial isolates except Salmonella and Shigella species were found resistant to commonly used antibiotics such as ampicillin (57.5%, trimethoprim/sulfamethoxaole (39.1%, amoxicillin/clavulanic acid (37.4%, cefixime (34.5%, tetracycline (29.1%, ceftazidime (26.3%, ofloxacin (25.9%, amikacin (8.7%, and gentamicin (2.7% but sensitive to imipenem and piperacillin/tazobactam. Conclusion: Natural sources of water in east Sikkim are grossly contaminated with bacteria including enteropathogens. The consumption of untreated water from these sources might pose health risk to consumers.
Kouassi, Kra Athanase; Dadie, Adjéhi Thomas; N'Guessan, Kouadio Florent; Dje, Koffi Marcellin; Loukou, Yao Guillaume
The aim of this study was to evaluate the prevalence of Clostridium difficile and Clostridium perfringens in cooked beef sold in the streets in Côte d'Ivoire and their antimicrobial susceptibility. A total of 395 kidney and flesh samples of cooked beef were collected from vendors at Abidjan and subjected to C. difficile and C. perfringens isolation and identification by using biochemical tests, API 20A system and PCR detection. Subsequently, the antimicrobial susceptibility test was performed for confirmed isolates. Our results showed the prevalence of 12.4% for C. difficile (11.04% in kidney and 13.45% in flesh) and 5.06% for C. perfringens (2.32% in kidney and 7.17% in flesh). Metronidazole and vancomycin remained the most potent antimicrobial agents against C. difficile while metronidazole and penicillin G were the most potent agents against C. perfringens. The resistance rates to tetracycline, doxycycline, chloramphenicol and erythromycin against C. difficile and C. perfringens isolates ranged from 2.05% to 8.16% and from 20% to 50%, respectively. Among all antimicrobial agents tested against C. difficile, percentages of resistance to quinolones ciprofloxacin, norfloxacin and nalidixic acid as well as to gentamicin and cefotaxime were the highest. Eight resistant phenotypes were defined for C. difficile isolates and eleven resistant phenotypes for C. perfringens isolates. Clindamycin/gentamicin/cefotaxime/ciprofloxacin/norfloxacin/nalidixic acid resistance was the most common phenotype for C. difficile (55.10% of isolates) while norfloxacin/nalidixic acid resistance was the most common phenotype for C. perfringens (20% of isolates).
Wang, Dong; Zhang, Limei; Zhou, Xuezhang; He, Yulong; Yong, Changfu; Shen, Mingliang; Szenci, Otto; Han, Bo
Staphylococcus aureusis the leading pathogen involved inbovine mastitis, but knowledgeabout antimicrobial resistance, virulence factors, and genotypes of Staphylococcus aureus resulting in bovine mastitis in Ningxia, China, is limited. Therefore, antimicrobial susceptibility, virulence gene, and randomly amplified polymorphic DNA (RAPD) analyses of Staph. aureus were carried out. A total of 327 milk samples from cows with clinical and subclinical mastitis in 4 regions of Ningxia were used for the isolation and identification of pathogens according to phenotypic and molecular characteristics. Antimicrobial susceptibility against 22 antimicrobial agents was determined by disk diffusion. The presence of 8 virulence genes in Staph. aureus isolates was tested by PCR. Genotypes of isolates were investigated based on RAPD. Results showed that 35 isolates obtained from mastitis milk samples were identified as Staph. aureus. The isolates were resistant to sulfamethoxazole (100%), penicillin G (94.3%), ampicillin (94.3%), erythromycin (68.6%), azithromycin (68.6%), clindamycin (25.7%), amoxicillin (11.4%), and tetracycline (5.7%). All of the isolates contained one or more virulence genes with average (standard deviation) of 6.6±1.6. The most prevalent virulence genes were hlb (97.1%), followed by fnbpA, hla, coa (94.3% each), nuc (85.7%), fnbpB (80%), clfA (77.1%), and tsst-1 (40%). Nine different gene patterns were found and 3 of them were the dominant gene combinations (77.1%). Staphylococcus aureus isolates (n=35) were divided into 6 genotypes by RAPD tying, the genotypes III and VI were the most prevalent genotypes. There was greatvariation in genotypes of Staph. aureus isolates, not only among different farms, but also within the same herd in Ningxia province. The study showed a high incidence of Staph. aureus with genomic variation of resistance genes, which is matter of great concern in public and animal health in Ningxia province of China.
This document includes the recommendations from the Spanish antibiogram committee (The MENSURA group, Mesa Española de Normalización de la Sensibilidad y Resistencia a los Antimicrobianos, under the auspices of the Sociedad Española de Quimioterapia and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica) for the selection of antimicrobials for susceptibility testing. Separate tables for each group of organism with proposed susceptibility and resistance breakpoints are updated and comparatively presented with those of other groups, such us NCCLS, CA-SFM and BSAC. The susceptibility breakpoint tends to identify the fully susceptible population, which probably lacks any specific resistance mechanism. The analysis of MIC distributions for different homogeneous populations (same species) is used to define breakpoints for susceptibility. The resistance breakpoint is based on pharmacological and clinical data obtained when the corresponding antibiotic is administered with a conventional schedule. The primary objective of the Spanish MENSURA group is to contribute to the international consensus on the establishment of breakpoints.
Chang, Ting-Wei; Wang, Chiu-Feng; Huang, Hsin-Jye; Wang, Iren; Hsu, Shang-Te Danny; Liao, You-Di
Antimicrobial peptides (AMPs) are important components of the host innate defense mechanism against invading pathogens. Our previous studies have shown that the outer membrane protein, OprI from Pseudomonas aeruginosa or its homologue, plays a vital role in the susceptibility of Gram-negative bacteria to cationic α-helical AMPs (Y. M. Lin, S. J. Wu, T. W. Chang, C. F. Wang, C. S. Suen, M. J. Hwang, M. D. Chang, Y. T. Chen, Y. D. Liao, J Biol Chem 285:8985–8994, 2010, http://dx.doi.org/10.1074...
Aarestrup, Frank Møller; Jorsal, Sven Erik Lind; Jensen, N. E.
antimicrobial agents. The majority of cases were lung diseases (57%), followed by septicaemia (16%), meningitis (15%) and endocarditis (8%). Almost 96% of the isolates could be typed using the 28 antisera. The most common serotype was serotype 2 (29%), followed by serotype 7 (17%), and serotypes 3, 4 and 8 (9...... to lincomycin and spiramycin. The differences in susceptibility between isolates of serotype 2 and the other serotypes were statistically significant. Compared to a previous Danish study the distribution of serotypes of S. suis causing infections among pigs in Denmark has changed during the last 15 years....
Madoroba, Evelyn; Kapeta, Daniel; Gelaw, Awoke K
Antimicrobial resistant Salmonella are among the leading causes of foodborne infections. Our aim was to determine Salmonella contamination during cattle slaughter in South African rural abattoirs (n = 23) and environmental samples. Furthermore, antimicrobial resistance patterns of the Salmonella isolates were determined. Samples of cattle faeces (n = 400), carcass sponges (n = 100), intestinal contents (n = 62), hides (n = 67), and water from the abattoirs (n = 75) were investigated for Salmonella species using microbiological techniques and species-specific polymerase chain reaction targeting the invA gene. In total 92 Salmonella species isolates were recovered. The Salmonella mean frequency of occurrence on hides, carcasses, and intestinal contents was 35.37% (n = 81). Eleven faecal samples (2.75%) tested positive for Salmonella. The predominant serovar was Salmonella Enteritidis. Diverse serovars that were identified on carcasses were not necessarily found on the hides and intestinal contents. The inconsistent occurrence of the diverse Salmonella serovars on hides, carcasses, and intestinal contents implies that in addition to carriage on hides and in intestinal contents, other external factors also play an important role regarding carcass contamination. The 92 Salmonella were serotyped and tested for susceptibility towards the following antimicrobials: ampicillin, cefotaxime, enrofloxacin, kanamycin, and oxytetracycline using the disk diffusion method. Most Salmonella (n = 66; 71.7%) isolates were resistant to at least one antimicrobial with highest resistance observed towards oxytetracycline (51.90%), which highlights the need for strict hygiene during slaughter and prudent antimicrobial use during animal production. In conclusion, cattle slaughtered in South African rural abattoirs harbour diverse Salmonella serovars that are resistant to antimicrobials, which could be a public health risk. The findings should assist policymakers with improving implementation
Full Text Available Antimicrobial resistant Salmonella are among the leading causes of foodborne infections. Our aim was to determine Salmonella contamination during cattle slaughter in South African rural abattoirs (n = 23 and environmental samples. Furthermore, antimicrobial resistance patterns of the Salmonella isolates were determined. Samples of cattle faeces (n = 400, carcass sponges (n = 100, intestinal contents (n = 62, hides (n = 67, and water from the abattoirs (n = 75 were investigated for Salmonella species using microbiological techniques and species-specific polymerase chain reaction targeting the invA gene. In total 92 Salmonella species isolates were recovered. The Salmonella mean frequency of occurrence on hides, carcasses, and intestinal contents was 35.37% (n = 81. Eleven faecal samples (2.75% tested positive for Salmonella. The predominant serovar was Salmonella Enteritidis. Diverse serovars that were identified on carcasses were not necessarily found on the hides and intestinal contents. The inconsistent occurrence of the diverse Salmonella serovars on hides, carcasses, and intestinal contents implies that in addition to carriage on hides and in intestinal contents, other external factors also play an important role regarding carcass contamination. The 92 Salmonella were serotyped and tested for susceptibility towards the following antimicrobials: ampicillin, cefotaxime, enrofloxacin, kanamycin, and oxytetracycline using the disk diffusion method. Most Salmonella (n = 66; 71.7% isolates were resistant to at least one antimicrobial with highest resistance observed towards oxytetracycline (51.90%, which highlights the need for strict hygiene during slaughter and prudent antimicrobial use during animal production. In conclusion, cattle slaughtered in South African rural abattoirs harbour diverse Salmonella serovars that are resistant to antimicrobials, which could be a public health risk. The findings should assist policymakers with improving
Anne V Gautier-Bouchardon
Full Text Available Mycoplasma (M. bovis is frequently implicated in respiratory diseases of young cattle worldwide. Today, to combat M. bovis in Europe, only antimicrobial therapy is available, but often fails, leading to important economical losses. The antimicrobial susceptibility of M. bovis is not covered by antimicrobial resistance surveillance networks. The objectives of this study were to identify resistances that were acquired over the last 30 years in France and to determine their prevalence within contemporary strains. The minimum inhibition concentration (MIC values of 12 antimicrobials, considered active on M. bovis, were compared, using an agar dilution method, between 27 and 46 M. bovis isolates respectively obtained in 1978-1979 and in 2010-2012 from 73 distinct respiratory disease outbreaks in young cattle all over France. For eight antimicrobials, resistances were proven to be acquired over the period and expressed by all contemporary strains. The increase of the MIC value that inhibited 50% of the isolates (MIC50 was: i substantial for tylosin, tilmicosin, tulathromycin and spectinomycin, from 2 to >64, 2 to >128, 16 to 128 and 4 to >64 µg/mL, respectively, ii moderate for enrofloxacin, danofloxacin, marbofloxacin and oxytetracycline, from 0.25 to 0.5, 0.25 to 0.5, 0.5 to 1, 32 to >32 µg/mL, respectively. No differences were observed for gamithromycin, tildipirosin, florfenicol and valnemulin with MIC50 of 128, 128, 8, <0.03 µg/mL, respectively. If referring to breakpoint MIC values published for respiratory bovine pathogens, all contemporary isolates would be intermediate in vivo for fluoroquinolones and resistant to macrolides, oxytetracycline, spectinomycin and florfenicol.
Gautier-Bouchardon, Anne V; Ferré, Séverine; Le Grand, Dominique; Paoli, Agnès; Gay, Emilie; Poumarat, François
Mycoplasma (M.) bovis is frequently implicated in respiratory diseases of young cattle worldwide. Today, to combat M. bovis in Europe, only antimicrobial therapy is available, but often fails, leading to important economical losses. The antimicrobial susceptibility of M. bovis is not covered by antimicrobial resistance surveillance networks. The objectives of this study were to identify resistances that were acquired over the last 30 years in France and to determine their prevalence within contemporary strains. The minimum inhibition concentration (MIC) values of 12 antimicrobials, considered active on M. bovis, were compared, using an agar dilution method, between 27 and 46 M. bovis isolates respectively obtained in 1978-1979 and in 2010-2012 from 73 distinct respiratory disease outbreaks in young cattle all over France. For eight antimicrobials, resistances were proven to be acquired over the period and expressed by all contemporary strains. The increase of the MIC value that inhibited 50% of the isolates (MIC50) was: i) substantial for tylosin, tilmicosin, tulathromycin and spectinomycin, from 2 to >64, 2 to >128, 16 to 128 and 4 to >64 µg/mL, respectively, ii) moderate for enrofloxacin, danofloxacin, marbofloxacin and oxytetracycline, from 0.25 to 0.5, 0.25 to 0.5, 0.5 to 1, 32 to >32 µg/mL, respectively. No differences were observed for gamithromycin, tildipirosin, florfenicol and valnemulin with MIC50 of 128, 128, 8, <0.03 µg/mL, respectively. If referring to breakpoint MIC values published for respiratory bovine pathogens, all contemporary isolates would be intermediate in vivo for fluoroquinolones and resistant to macrolides, oxytetracycline, spectinomycin and florfenicol.
Vieira, Regine H S Dos F; Carvalho, Edirsana M R; Carvalho, Fatima C T; Silva, Camila M; Sousa, Oscarina V; Rodrigues, Dalia P
This study aimed to test the susceptibility of Escherichia coli strains isolated from the water, bottom sediments and individuals cultivated in shrimp farm ponds, to antibiotics belonging to different families, namely B-Lactams: Imipenem (IPM; 10 micro g), Ampicillin (AMP; 10 micro g), Cephalothin (CEP; 30 micro g), Cefoxitin (FOX; 30 micro g), Ceftriaxone (CRO; 30 micro g); Tetracycline: Tetracycline (TCY; 30 micro g); Aminoglycosides: Gentamicin (GEN; 10 micro g), Amikacin (AMK; 30 micro g); Chloramphenicol: Chloramphenicol (CHO; 30 micro g); Fluoroquinolones: Ciprofloxacin (CIP; 5 micro g); Nitrofurans: Nitrofurantoin (NIT; 300 micro g); Sulfonamides: Trimethoprim-Sulfamethoxazole (SXT; 30 micro g); Quilononas: Nalidixic Acid (NAL; 30 micro g). In the laboratory, the method of dissemination (Test Kirby-Bauer) was performed in order to fulfill the antibiogram tests. The results showed high indices of resistance to Imipenem, Cephalothin and Ampicillin. Chloramphenicol, Nitrofurantoin, Cefoxitin, Ceftiaxone and Ciprofloxacin have displayed the highest index of sensitive strains. The antibiotic resistance index (ARI) and the multiple resistance index (MAR) varied within the ranges of 0.068-0.077 and 0.15-0.39, respectively. More than 90.5% of strains of Escherichia coli showed a variety of resistance profiles to the tested antibiotics. The high indices of resistance may be a consequence of indiscriminate use of antibiotics, but also the transfer of resistance through mobile genetic elements found in shrimp farms.
Wendy Irene Sligl
Conclusions: ICU-acquired Gram-negative bacteremia is associated with high mortality. Resistance to ciprofloxacin, piperacillin/tazobactam, and carbapenems was common. Coronary artery disease, immune suppression, and inadequate empiric antimicrobial therapy were independently associated with increased mortality.
Salmonella Kentucky has become the predominate serotype recovered from broiler slaughter in the United States and the prevalence of antimicrobial resistance (AMR) has increased dramatically in this serotype. Relationships between AMR, genotype, and plasmid replicon types were characterized for 600 ...
Wegener, H C; Watts, J.L.; Salmon, S A; Yancey, R J
Exudative epidermitis or greasy pig syndrome is caused by the coagulase-variable staphylococcal species Staphylococcus hyicus. Treatment of this disease is problematic because of the limited number of antimicrobial agents available for this purpose. Thirteen antimicrobial agents were evaluated for their activities against 100 S. hyicus strains isolated from pigs with exudative epidermitis. Novobiocin was the most active compound tested, with an MIC for 90% of the strains tested (MIC90) of < o...
The aim of the present study was to evaluate the antifungal susceptibility profile of Trichosporon species isolated from different sources employing the Clinical and Laboratory Standards Institute (CLSI) method and E-test method. Thirty-four isolates of Trichosporon spp. and six CBS reference samples were tested for their susceptibility to Amphotericin B, 5-flucytosine, Fluconazole, Itraconazole, Voriconazole and Terbinafine. All species showed high Minimun Inhibitory Concentrations (MIC) for...
F J Mansur
Full Text Available The aim of this study was to evaluate the rate of bacterial colonisation and catheter related blood stream infections (CRBSI together with the antibiotic susceptibility patterns in a tertiary care hospital. CRBSI was detected with semi-quantitative and quantitative methods. The antimicrobial susceptible patterns of the isolated organisms were performed by Kirby Bauer disk diffusion method. The rate of catheter colonisation and CRBSI were 42.1% and 14% (16.1/1000 catheter days respectively. The most common causative pathogens were Pseudomonas sp. (23.7%, Acinetobacter sp. (18.4%, Staphylococcus aureus (13.2% and Enterobacteriaceae (10.5%. The rate of isolation of methicillin resistance S. aureus, imipenem resistant Pseudomonas sp. and extended spectrum β lactamase producing Enterobacteriaceae were 60%, 44.0% and 100%. The result of this study would be useful for control and treatment of CRBSI.
Campbell, James I; Lam, Thi Minh Yen; Huynh, Thi Loan; To, So Diep; Tran, Thi Thu Nga; Nguyen, Van Minh Hoang; Le, Thanh Son; Nguyen, van Vinh Chau; Parry, Christopher; Farrar, Jeremy J; Tran, Tinh Hien; Baker, Stephen
Clostridium tetani is the etiologic agent of the muscle-spasming disease tetanus. Despite an effective vaccine, tetanus is an ongoing problem in some developing countries. Diagnosis by bacterial culture is not done because it is generally unnecessary and the entry of route of the bacteria can be inapparent. We attempted to isolate and evaluate C. tetani from the wounds of 84 patients with tetanus. We effectively isolated C. tetani from 45 patients. All strains tested positive by polymerase chain reaction for the gene encoding tetanus neurotoxin. Antimicrobial susceptibilities were determined by disc diffusion and E-test. All C. tetani isolates were susceptible to penicillin and metronidazole but resistant to co-trimoxazole. Despite treatment with high doses of penicillin, C. tetani was isolated after 16 days of intravenous penicillin in two cases. These data show that the intravenous route for penicillin may be inadequate for clearing the infection and emphasizes wound debridement in the treatment of tetanus.
A K Kapoor
Full Text Available The aim of present study to analyze the occurrence and in-vitro antimicrobial susceptibility of bacterial pathogens isolated from surgical wound infections. Specimens from a total of 129 patients undergoing either emergency or elective surgery were collected from infected sites or stitch lines and inoculated onto appropriate media. The bacterial cultures were identified utilizing standard microbiological and biochemical methods. Isolates were tested for susceptibility to antimicrobials using the Kirby Bauer disk diffusion method. Statistical analysis was performed using the chi-square test. Of 129 patients investigated (62 emergency and 67 elective surgery cases, bacterial isolates were isolated with almost equal frequency both from emergency and elective surgery cases. Of 108 (83.72% culture positive samples, 62 (57.41% were Gram negative, 39 (36.11% Gram positive, and 7 (6.48% showed multiple organisms. Of total 115 bacteria isolated (101 single and 7 double organisms culture positive, 33 (28.69% were Escherichia coli and were also the commonest; followed by Staphylococcus aureus, 30 (26.09% cases. S. aureus and Streptococcus spp. showed maximum susceptibility (100% to linezolid and vancomycin. Maximum susceptibility of E. coli was observed to ciprofloxacin (75.7%, followed by gentamicin (54.5%; of Klebsiella spp. to ceftriaxone and gentamicin (66.6% each, of Proteus spp. to gentamicin (70% followed by ciprofloxacin (60%, and of Pseudomonas aeruginosa to piperacillin (100% and tobramycin (71.4%. E. coli and S. aureus were the most common and Salmonella spp. and Acinetobacter spp. were the least common organism causing surgical site infections. The definitive therapy included ciprofloxacin and gentamicin for E. coli; linezolid and vancomycin for S. aureus and Streptococcus spp; ceftriaxone and ciprofloxacin for Klebsiella spp., Citrobacter spp., acinetobacter spp and Salmonella spp.
Fatma Abdelaziz Amer; Eman Mohamed Elbehedy; Mohamed Elahmady
Objectives:To determine the incidence of resistance of Streptococcus (Strep).pneumoniae isolated in our lo-cality to erythromycin,to screen for the two resistance determinants erm(B)and mef(A)genes,and to identi-fy the susceptibility profile to commonly used antibiotics.Methods:Samples were collected from patients at-tending the Outpatient Department of Zagazig University Hospital,Zagazig,Egypt,between February 2006 and March 2007.Strep.pneumoniae was identified by conventional procedures.Susceptibilities to erythromycin and 15 antibiotics were identified by disc diffusion method,as outlined by CLSI.E-test was used for MIC de-termination of erythromycin.erm(B)and mef(A)genes were detected by PCR.Results:Eighty-one Strep. pneumoniae strains were identified.Fifty-one of them (63 %)were erythromycin-resistant,and mef(A)gene was the predominant resistance determinant.Vancomycin,imipenem and gatifloxacin had the best activity a-gainst the isolates,whereas tetracycline had the least.Forty-two (51.85%)out of the 81 Strep.pneumoniae strains were multidrug-resistant.Conclusions:High incidence of resistance to erythromycin and multiple anti-microbials existed.mef(A)was the principal erythromycin-resistance gene.
Thomsen, Natalie A; Hammer, Katherine A; Riley, Thomas V; Van Belkum, Alex; Carson, Christine F
The aim of this study was to seek additional data on the antimicrobial susceptibility of Staphylococcus spp. after habituation to low levels of the topical antimicrobial agent tea tree (Melaleuca alternifolia) oil. Meticillin-susceptible Staphylococcus aureus (MSSA), meticillin-resistant S. aureus (MRSA) and coagulase-negative staphylococci (CoNS) were habituated to 0.075% tea tree oil for 3 days. Subsequently, the susceptibility of five isolates each of MSSA, MRSA and CoNS to fusidic acid, mupirocin, chloramphenicol, linezolid and vancomycin was determined by Etest, and susceptibility to tea tree oil, terpinen-4-ol, carvacrol and triclosan was determined by agar dilution. Following habituation to 0.075% tea tree oil, antimicrobial MICs differed between control and habituated isolates on 33 occasions (out of a possible 150), with MICs being higher in habituated isolates on 22 occasions. Using clinical breakpoint criteria, one MSSA isolate changed susceptibility category from vancomycin-susceptible (MIC=2 μg/mL) to intermediate susceptibility (MIC=3 μg/mL) after habituation in one of two replicates. For the non-antibiotic antimicrobial agents, MICs of habituated and control isolates differed on 12 occasions (out of a possible 120); 10 occasions in MRSA and 2 occasions in MSSA. MICs were higher for habituated isolates on five occasions. However, all the differences were one serial dilution only and were not regarded as significant. Habituation to sublethal concentrations of tea tree oil led to minor changes in MICs of antimicrobial agents, only one of which may have been clinically relevant. There is no evidence to suggest that tea tree oil induces resistance to antimicrobial agents.
Garcia Doroti de Oliveira
Full Text Available Forty-six S. maltophilia isolates obtained from hospital clinical specimens were studied for protease (caseinase and elastase production, hemolytic activity, adhesion to HEp-2 cells, plastic and glass. Susceptibility to antimicrobial agents was also evaluated. The majority of isolates were obtained from respiratory tract secretions of patients using medical devices. All the isolates grown overnight were able to hydrolyze casein at 30masculineC and 37masculineC. After 72h, all the isolates hydrolyzed elastase at 30masculineC and 40 isolates (87% at 37masculineC. Most of the isolates presented hemolytic activity after 96h of incubation at both temperatures. Rabbit blood showed the hightest hemolytic activity, after 96h 61% and 98% of tested isolates presented beta-hemolysis at 30masculineC and 37masculineC, respectively. All isolates were susceptible to trimethoprim-sulfametoxazole and were resistant to most beta-lactams tested. By the dilution method, S. maltophilia showed a high susceptibility to ticarcillin-clavulanate and a lower susceptibility to ciprofloxacin than the agar diffusion. The isolates showed adhesion to HEp-2 cells, plastic and glass. The proteolytic activities and adhesion to inanimate surfaces detected in S. maltophilia can be related to the pathogenesis of this bacterium and/or medical device colonization which favors the development of nosocomial infections.
Yang, Cheng-Yao; Lin, Chao-Nan; Lin, Chuen-Fu; Chang, Tsung-Chou; Chiou, Ming-Tang
In total, 211 isolates of A. pleuropneumoniae were collected from pigs with hemorrhagic pneumonia at slaughterhouses during 2002-2007. Serotypes, antimicrobial susceptibility and minimum inhibitory concentration (MIC) values were determined for each isolate of A. pleuropneumoniae to 10 antimicrobial agents. Serovar 1 of A. pleuropneumoniae was predominant in Taiwan in 138 of the 211 isolates, followed by serovars 2 and 5. More than 90% of collected isolates were sensitive to ceftiofur, cephalothin, and chloramphenical. However, lincospectin and gentamicin were relatively less susceptible with sensitivities of only 2.4 and 5.7%, respectively. Additionally, ceftiofur had the highest in vitro activity with an MIC(50) of 2.2 µg/ml, followed by cephalothin (2.7 µg/ml) and chloramphenicol (7.9 µg/ml). Lincospectin had the least activity with MIC(50) and MIC(90) values of 73.9 and 114.5 µg/ml, respectively. The data indicate that ceftiofur and cephalothin were extremely active against A. pleuropneumoniae and with minimum MIC values. These drugs are suitable for controlling and treating hemorrhagic pleuropneumonia outbreaks in swine.
Mariana Tavares Dias
Full Text Available Foodborne disease caused by microorganisms is a problem of public health. Minas soft cheese is a national product manufactured using simple technology; it has high level of acceptance in the country making its production an important economic activity. Many microorganisms may be present in foods including the bacterium Escherichia coli (E. coli. Overall, E. coli is a harmless commensal bacterium; however, some strains may have a pathogenic potential. Several outbreaks of foodborne diseases associated with consumption of contaminated cheese have been reported, and the presence of pathogenic strains of E. coli has increased. The objective of this study was to isolate, evaluate the antimicrobial susceptibility, and characterize, by Multiplex PCR, the pathogenic E. coli strains isolated from Minas cheese commercialized in Rio de Janeiro. Thirty samples were analyzed and five strains of E. coli (EPEC were identified. The assessment of antimicrobial susceptibility revealed 40% of the isolates resistant to ampicillin and 40% with intermediate resistance to ampicillin-sulbactam combination. These findings are a warning signal to health authorities since Minas cheese is a ready to eat food product, and therefore should not pose health risks to the population.
Hendriksen, Rene S.; Seyfarth, Anne Mette; Jensen, Arne Bent;
. 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......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...
Evaluation of feeding distiller's grains, containing virginiamycin, on antimicrobial susceptibilities in fecal isolates of Enterococcus and Escherichia coli and prevalence of resistance genes in cattle.
Edrington, T S; Bischoff, K M; Loneragan, G H; Nisbet, D J
Dried distiller's grains (DG) produced from ethanol fermentations dosed with 0 (control), 2, or 20 mg/kg virginiamycin-based product or spiked with virginiamycin (VM) postfermentation were fed to cattle and effects on antimicrobial susceptibility, and prevalence of antimicrobial resistance genes in commensal bacteria was examined. Biological activity assays of DG (from each fermentation) indicated a concentration of 0, 0.7, and 8.9 mg/kg VM, respectively. Twenty-four crossbred beef steers were fed 1 of 4 diets (containing 8% of each of the different batches of DG) and a fourth using 8% of the control DG (0 mg/kg VM) + 0.025 g/kg V-Max50 (positive control) for 7 wk. Fecal samples were collected weekly throughout the experimental period and cultured for Escherichia coli and Enterococcus, and isolates were examined for antimicrobial susceptibility, antimicrobial resistance genes (vatE, ermB, and msrC in Enterococcus), and integrons (E. coli). No treatment differences (P > 0.05) were observed in antimicrobial susceptibility of the E. coli isolates. Enterococcus isolates were resistant to more antimicrobials; however, this was influenced by the species of Enterococcus and not treatment (P > 0.10). The prevalence of ermB was greater (P < 0.05) in the control isolates after 4 and 6 wk while at wk 7, prevalence was greater (P < 0.01) in the 0.7 and 8.9 mg/kg VM treatments. Taken together, the minor treatment differences observed for the presence of ermB coupled with the lack of effect on antimicrobial susceptibility patterns suggest that feeding DG containing VM residues should have minimal if any impact on prevalence of antimicrobial resistance.
Olkkola, Satu; Kovanen, Sara; Roine, Johanna; Hänninen, Marja-Liisa; Hielm-Björkman, Anna; Kivistö, Rauni
In recent years, increasing numbers of consumers have become interested in feeding raw food for their pet dogs as opposed to commercial dry food, in the belief of health advantages. However, raw meat and internal organs, possibly contaminated by pathogens such as Campylobacter spp., may pose a risk of transmission of zoonoses to the pet owners. Campylobacter jejuni is the leading cause of bacterial gastroenteritis in humans but C. upsaliensis has also been associated with human disease. In this study we investigated the effect of different feeding strategies on the prevalence of Campylobacter spp. in Finnish dogs. We further characterized the isolates using multilocus sequence typing (MLST), whole-genome (wg) MLST and antimicrobial susceptibility testing. Dogs were sampled before and after a feeding period consisting of commercial raw feed or dry pellet feed. Altogether 56% (20/36) of the dogs yielded at least one Campylobacter-positive fecal sample. C. upsaliensis was the major species detected from 39% of the dogs before and 30% after the feeding period. Two C. jejuni isolates were recovered, both from raw-fed dogs after the dietary regimen. The isolates represented the same genotype (ST-1326), suggesting a common infection source. However, no statistically significant correlation was found between the feeding strategies and Campylobacter spp. carriage. The global genealogy of MLST types of dog and human C. upsaliensis isolates revealed weakly clonal population structure as most STs were widely dispersed. Major antimicrobial resistance among C. upsaliensis isolates was against streptomycin (STR MIC > 4 mg/l). Apart from that, all isolates were highly susceptible against the antimicrobials tested. Mutations were found in the genes rpsL or rpsL and rsmG in streptomycin resistant isolates. In conclusion, increasing trend to feed dogs with raw meat warrants more studies to evaluate the risk associated with raw feeding of pets in transmission of zoonoses to humans.
Al-Ashmawy, Maha Abdou; Sallam, Khalid Ibrahim; Abd-Elghany, Samir Mohammed; Elhadidy, Mohamed; Tamura, Tomohiro
The present work was undertaken to study the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) in raw milk and dairy products in Mansoura City, Egypt. MRSA was detected in 53% (106/200) among all milk and dairy products with prevalence rates of 75%, 65%, 40%, 50%, and 35% in raw milk, Damietta cheese, Kareish cheese, ice cream, and yogurt samples, respectively. The mean S. aureus counts were 3.49, 3.71, 2.93, 3.40, and 3.23 log10 colony-forming units (CFU)/g among tested raw milk, Damietta cheese, Kareish cheese, ice cream and yogurt, respectively, with an overall count of 3.41 log10 CFU/g. Interestingly, all recovered S. aureus isolates were genetically verified as MRSA strains by molecular detection of the mecA gene. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, sec) were detected in all isolates. The antimicrobial susceptibility pattern of recovered MRSA isolates against 13 tested antimicrobials revealed that the least effective drugs were penicillin G, cloxacillin, tetracycline, and amoxicillin with bacterial resistance percentages of 87.9%, 75.9%, 65.2%, and 55.6%, respectively. These findings suggested that milk and dairy products represent a potential infection risk threat of multidrug-resistant and toxigenic S. aureus in Egypt due to neglected hygienic practices during production, retail, or storage stages. These findings highlighted the crucial importance of applying more restrictive hygienic measures in dairy production in Egypt for food safety.
Mohammad Salehi; Abdolmajid Ghasemian; Farshad Nojoomi; Mohammad Karim Rahimi
ABSTRACT Objective:To assess the antimicrobial susceptibility pattern ofESKAPE pathogens from Neyshabur, Iran during 2013–2015. Methods: A total of 345 isolates including 62Staphylococcus aureus(S. aureus), 38 Enterobacterspp. (including 14Enterobacter agglomerans, 6Enterobacter aerogenes and other 18Enterobacterspp.), 123Enterococcus faecium, 78Klebsiella pneumonia, 10 Pseudomonas aeruginosa and 34Acinetobacter baumannii were isolated. The antimicrobial susceptibility pattern of isolates was conducted with Kirby Bauer method. Data were analyzed withSPSS 20.0 software usingF- andt-tests. Results:AmongS. aureus isolates, the highest resistance was observed against nalidixic acid (81.35%) and cefixime (74.50%). Thirty-three (53.22%)S. aureus isolates were cefoxitin resistant (methicillin-resistantS. aureus). The majority ofEnterobacter species was resistant to amikacin (100.00%) and cephalotin (66.60%). MostEnterococcus faecium isolates were resistant to nalidixic acid (89.43%) and amikacin (83.33%), but vancomycin-resistant enterococci isolates were not detected. Moreover, amongKlebsiella pneumonia, the highest resistance was observed to nalidixic acid (20.98%) and cotrimoxazole (28.39%). Furthermore, allPseudomonas aeruginosa isolates were resistant to cefotaxime (100.00%) and majority to nitroforantoin (88.80%).Acinetobacter baumannii isolates showed the highest and the lowest resistance to cefotaxime (100.00%) and cefixime (88.71%), respectively. Conclusions:The prevalence ofESKAPE pathogens from northeast region was low, but majority of them exhibited high rate of antibiotic resistance to common used antimicrobial agents.
Tamang, Migma Dorji; Gurung, Mamata; Nam, Hyang-Mi; Moon, Dong Chan; Jang, Geum-Chan; Jung, Suk-Chan; Lim, Suk-Kyung
This study compared the antimicrobial susceptibility and prevalence of virulence genes in Salmonella enterica Typhimurium isolated from healthy and diseased pigs in Korea. A total of 456 Salmonella Typhimurium isolated from healthy (n = 238) and diseased (n = 218) pigs between 1998 and 2011 were investigated. In total, 93.4% of the Salmonella Typhimurium isolates were resistant to at least one antimicrobial agent tested. The isolates were most often resistant to tetracycline (85.7%), followed by streptomycin (83.6%), nalidixic acid (67.3%), ampicillin (49.3%), chloramphenicol (42.8%), and gentamicin (37.1%). Moreover, multidrug resistance phenotype and resistance to ampicillin, florfenicol, gentamicin, nalidixic acid, neomycin, streptomycin, and tetracycline were significantly higher (P invA, spiA, msgA, sipB, prgH, spaN, tolC, lpfC, sifA, sitC, and sopB virulence genes. The prevalence of orgA, pagC, and iroN were 50.2, 74.1, and 91.0%, respectively, whereas isolates carrying cdtB (1.5%), pefA (7.0%), and spvB (14.9%) were identified much less frequently. Furthermore, the prevalence of invA, lpfC, orgA, pagC, and iroN was significantly higher (P < 0.01) among the isolates from the diseased pigs than in isolates from the healthy pigs. Our results demonstrated that, among diseased pigs, there was significantly higher resistance to some antimicrobials and greater prevalence of some virulence genes than in healthy pigs, indicating the role these factors play in pathogenesis. Multidrug-resistant Salmonella isolates that carry virulence-associated genes are potentially more dangerous and constitute a public health concern. Thus, continuous surveillance of antimicrobial resistance and virulence characteristics in Salmonella is essential.
Hermoso de Mendoza, J; Arenas, A; Rey, J; Alonso, J M; Gil, M C; Naranjo, G; Hermoso de Mendoza, M
The Minimal Inhibitory Concentration (MIC) and Minimal Bacteriocidal Concentration (MBC) of 19 antimicrobials on 16 isolates of D. congolensis were determined. The potential field efficacy of the agents was evaluated by comparing the results with serum levels of drug unbound to proteins and the in vitro and in vivo findings of other authors. A modified standard microtechnique was used for serial dilution-antimicrobial sensitivity and found to be easy and reproducible. Erythromycin, spiramycin, penicillin G, ampicillin, chloramphenicol, the streptomycin, amoxicillin, the tetracyclines and novobiocin had high serum concentrations in comparison with their MBCs and were shown to have potential use for the treatment of dermatophilosis.
WANG Dongdong; LI Fuhua; LI Shihao; WEN Rong; XIANG Jianhai
Antimicrobial peptides (AMPs),as key immune effectors,play important roles in the innate immune system of invertebrates.Different types of AMPs,including Penaeidin,Crustin,ALF (antilipopolysaccharide factor) have been identified in different penaeid shrimp; however,systematic analyses on the function of different AMPs in shrimp responsive to different types of bacteria are very limited.In this study,we analyzed the expression profiles of AMPs in the Chinese shrimps,Fenneropenaeus chinensis,simultaneously by real-time RT-PCR (reverse transcription-polymerase chain reaction) when shrimp were challenged with Micrococcus lysodeikticus (Gram-positive,G+) or Vibrio anguillarium (Gram-negative,G).Different AMPs showed different expression profiles when shrimp were injected with one type of bacterium,and one AMP also showed different expression profiles when shrimp were challenged with different bacteria.Furthermore,the expression of these AMPs showed temporal expression profiles,suggesting that different AMPs function coordinately in bacteria-infected shrimp.An RNA interference approach was used to study the function of the Relish transcription factor in regulating the transcription of different AM Ps.The current study showed that Relish could regulate the transcription of different AMPs in shrimp.Differential expression profiles of AMPs in shrimp injected with different types of bacteria indicated that a complicated antimicrobial response network existed in shrimp.These data contribute to our understanding of immunity in shrimp and may provide a strategy for the control of disease in shrimp.
Wang, Dongdong; Li, Fuhua; Li, Shihao; Wen, Rong; Xiang, Jianhai
Antimicrobial peptides (AMPs), as key immune effectors, play important roles in the innate immune system of invertebrates. Different types of AMPs, including Penaeidin, Crustin, ALF (antilipopolysaccharide factor) have been identified in different penaeid shrimp; however, systematic analyses on the function of different AMPs in shrimp responsive to different types of bacteria are very limited. In this study, we analyzed the expression profiles of AMPs in the Chinese shrimps, Fenneropenaeus chinensis, simultaneously by real-time RT-PCR (reverse transcription-polymerase chain reaction) when shrimp were challenged with Micrococcus lysodeikticus (Gram-positive, G+) or Vibrio anguillarium (Gram-negative, G-). Different AMPs showed different expression profiles when shrimp were injected with one type of bacterium, and one AMP also showed different expression profiles when shrimp were challenged with different bacteria. Furthermore, the expression of these AMPs showed temporal expression profiles, suggesting that different AMPs function coordinately in bacteria-infected shrimp. An RNA interference approach was used to study the function of the Relish transcription factor in regulating the transcription of different AMPs. The current study showed that Relish could regulate the transcription of different AMPs in shrimp. Differential expression profiles of AMPs in shrimp injected with different types of bacteria indicated that a complicated antimicrobial response network existed in shrimp. These data contribute to our understanding of immunity in shrimp and may provide a strategy for the control of disease in shrimp.
Juliana M. A. Agostinho
Full Text Available Pyometra is recognized as one of the main causes of disease and death in the bitch, and Escherichia coli is the major pathogen associated with this disease. In this study, 70 E. coli isolates from the uteri horn, mouth, and rectum of bitches suffering from the disease and 43 E. coli isolates from the rectum of clinically healthy bitches were examined for the presence of uropathogenic virulence genes and susceptibility to antimicrobial drugs. DNA profiles of isolates from uteri horn and mouth in bitches with pyometra were compared by REP, ERIC, and BOX-PCR. Virulence gene frequencies detected in isolates from canine pyometra were as follows: 95.7% fim, 27.1% iss, 25.7% hly, 18.5% iuc, and 17.1% usp. Predominant resistance was determined for cephalothin, ampicillin, and nalidixic acid among the isolates from all sites examined. Multidrug resistance was found on ∼50% pyometra isolates. Using the genotypic methods some isolates from uteri, pus, and saliva of the same bitch proved to have identical DNA profiles which is a reason for concern due to the close relationship between household pets and humans.
Agostinho, Juliana M A; de Souza, Andressa; Schocken-Iturrino, Ruben P; Beraldo, Lívia G; Borges, Clarissa A; Avila, Fernando A; Marin, José M
Pyometra is recognized as one of the main causes of disease and death in the bitch, and Escherichia coli is the major pathogen associated with this disease. In this study, 70 E. coli isolates from the uteri horn, mouth, and rectum of bitches suffering from the disease and 43 E. coli isolates from the rectum of clinically healthy bitches were examined for the presence of uropathogenic virulence genes and susceptibility to antimicrobial drugs. DNA profiles of isolates from uteri horn and mouth in bitches with pyometra were compared by REP, ERIC, and BOX-PCR. Virulence gene frequencies detected in isolates from canine pyometra were as follows: 95.7% fim, 27.1% iss, 25.7% hly, 18.5% iuc, and 17.1% usp. Predominant resistance was determined for cephalothin, ampicillin, and nalidixic acid among the isolates from all sites examined. Multidrug resistance was found on ∼ 50% pyometra isolates. Using the genotypic methods some isolates from uteri, pus, and saliva of the same bitch proved to have identical DNA profiles which is a reason for concern due to the close relationship between household pets and humans.
Full Text Available Objectives: Class D oxacillinases are frequently acquired by gram negative bacteria in general and P. aeruginosa in particular.P. aeruginosa is commonly implicated in causing nosocomial infections. The evolution of antibiotic resistance inP. aeruginosa and the acquisition of blaOXA genes interfere with successful treatment.Methods: A total of 49 clinical isolates of P. aeruginosa were obtained from Rafidia Hospital, West Bank, Palestine.Antimicrobial susceptibility testing of the isolates was performed by the standard disc diffusion method following theguidelines of CLSI. The prevalence of class D β-lactamases (OXA groups I, II and III as well as the pseudomonas specificenzymes (CARB-3 were determined by PCR.Results: Susceptibility of P. aeruginosa to carbapenems was the highest 89%, and lowest to ticarcillin/clavulanic acid70%. This study revealed that P. aeruginosa produced oxacillinase enzymes at rates of: OXA-10 (40.8%, OXA-2 (20.4%and OXA-1 (18.4%. All ceftazidime resistant strains expressed OXA-1 and OXA-2, 18.4%. PSE group was expressed in10.2%.Conclusions: This is the first research conducted to investigate the correlation between OXA genes (blaOXA-1, bla-OXA-2 and blaOXA-10 and antimicrobial resistance among P. aeruginosa clinical isolates in Palestine. The results obtainedcould contribute to better treatment and reduction of the evolution of resistant strains. In addition, it will provideimportant information regarding the geographical distribution of class D β-lactamases. J Microbiol Infect Dis 2013; 3(2:56-60Key words: P. aeruginosa, β-lactamase, susceptibility, oxacillinases, blaOXA genes
Zhong, Daibin; Wang, Mei-Hui; Pai, Aditi; Yan, Guiyun
The flour beetle, Tribolium castaneum, is an intermediate host for the tapeworm Hymenolepis diminuta and has become an important genetic model to explore immune responses to parasite infection in insect hosts. The present study examined the immune responses to tapeworm infection in resistant (TIW1) and susceptible (cSM) strains of the red flour beetle, T. castaneum, using real-time quantitative reverse transcription PCR on 29 immunity-related genes that exhibit antimicrobial properties. Thirteen of the 29 genes showed constitutive differences in expression between the two strains. Fourteen to fifteen of the 29 genes exhibited significant differences in transcription levels when beetles were challenged with tapeworm parasite in the resistant and susceptible strains. Nine genes (GNBP3, cSPH2, lysozyme4, defensin1, PGRP-SA, defensin2, coleoptericin1, attacin2 and serpin29) in cSM and 13 genes (lysozyme2, proPO1, GNBP3, cSPH2, lysozyme4, defensin1, PGRP-SA, defensin2, coleoptericin1, attacin2, proPO2/3, PGRP-LE and PGRP-SB) in TIW1 were up-regulated by infections or showed parasite infection-induced expression. Seven genes (attacin2, coleoptericin1, defensin1, defensin2, lysozyme2, PGRP-SA and PGRP-SB) were more than 10 folds higher in the resistant TIW1 strain than in the susceptible cSM strain after exposure to tapeworm parasites. This study demonstrated the effects of genetic background, the transcription profile to parasite infection, and identified the immunity-related genes that were significantly regulated by the infection of tapeworms in Tribolium beetles.
Full Text Available Background Foodborne diseases are widespread and growing public health problem in developed and developing countries. There are many microorganisms act as etiological agents for foodborne diseases such as Campylobacter spp., Listeria, Staphylococcos, Salmonella, Bacillus, Yersinia spp. High prevalence of gastrointestinal illness, including fatal cases attributable to yersiniosis, is also observed in many developing countries. Objectives The purpose of this study was to investigate the prevalence of Yersinia enterocolitica and other Yersinia species in meat and chicken samples in various seasons and to determine their antibiotic resistance profile. Materials and Methods To investigate the prevalence of Yersinia spp., a total of 450 samples, including chicken (n = 226 and beef meat (n = 224 were collected from supermarkets in Tehran. All samples were transported on ice to the laboratory and microbiological analysis was carried out within 2 hours after the collection. Susceptibility testing of bacterial strains was according to CLSI guideline at 28˚C by the disk diffusion assay. Results From a total of 450 samples, (226 chickens and 224 beef meats, 70 (15.5% samples were positive for Yersinia spp. Of these isolates, (80% 56 species were identified as Y. enterocolitica, 8 (11% as Y. frederiksenii, 5 (7% as Y. intermedia and 1 (1.4% as Y. kristensenii. The highest rate of resistance was seen against cephalotin (98%, and ampicillin (52%. However, gentamicin and chloramphenicol were the most active antibiotics against the target cultures. Considering the season of isolation, Yersinia spp. were frequently isolated in autumn (52%, followed by spring (29%. Conclusions Y. enterocolitica was the most spp. distributed among other species. Many factors, such as isolation assay, season, and geographical location play critical role in reports of increase or decrease in the prevalence of the Yersinia spp. all over the world. Our findings demonstrate that the
Clostridium difficile is commonly associated with a spectrum of disease in humans referred to as C. difficile-associated disease (CDAD) and use of antimicrobials is considered a risk factor for development of disease in humans. Clostridium difficile can also inhabit healthy food animals and transmi...
Nemes-Nikodém, Éva; Brunner, Alexandra; Pintér, Dóra; Mihalik, Noémi; Lengyel, György; Marschalkó, Márta; Kárpáti, Sarolta; Szabó, Dóra; Ostorházi, Eszter
Emergence and spread of antimicrobial resistance in Neisseria gonorrhoeae is a major public health concern worldwide. The current study aims to determine the antimicrobial resistance in N. gonorrhoeae and associated molecular typing to enhance gonococcal antimicrobial surveillance in Hungary. In the National N. gonorrhoeae Reference Laboratory of Hungary 187 N. gonorrhoeae infections were detected in 2013, antibiograms were determined for all the isolated strains, and 52 (one index strain from every sexually contact related group) of them were also analysed by the N. gonorrhoeae multi-antigen sequence typing (NG-MAST) method. Twenty-two different NG-MAST sequence types (STs) were identified, of which 8 STs had not been previously described. In Hungary, the highly diversified gonococcal population displayed high resistance to penicillin, ciprofloxacin and tetracycline (the antimicrobials previously recommended for gonorrhoea treatment). Resistance to the currently recommended extended spectrum cephalosporines were rare: only two of the expected strains, an ST 1407 and an ST 210, had cefixime MIC above the resistance breakpoint. By the revision of our National Treatment Guideline, it must be considered, that the azithromycin resistance is about 60% among the four most frequently isolated STs in Hungary.
Aarestrup, Frank Møller; Lertworapreecha, M.; Evans, M.C.;
Objectives: This study was conducted to investigate the occurrence of antimicrobial resistance among Salmonella Weltevreden isolates from different sources in South-East Asia (Indonesia, Laos, Malaysia, Taiwan, Thailand, Vietnam), Australia, Denmark, New Zealand and the USA. Methods: A total of 503...
Cherkaoui, A; Diene, S M; Emonet, S; Renzi, G; Francois, P; Schrenzel, J
The purpose of this study was to analyze the molecular mechanisms of ampicillin-resistant Haemophilus influenzae isolated in Geneva, Switzerland. We investigated the association between specific patterns of amino acid substitutions in penicillin-binding protein 3 (with or without β-lactamase production) and β-lactam susceptibility. Another main focus for this study was to compare the accuracy of disk diffusion and Etest methods to detect resistance to ampicillin and amoxicillin/clavulanic acid. The antibiotic susceptibility to β-lactam antibiotics of 124 H. influenzae isolates was determined by disk diffusion and Etest methods, and interpreted by European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) breakpoints. Alterations in PBP3 were investigated by sequencing the ftsI gene. Of the 124 clinical isolates analyzed, ampicillin resistance was found in 36% (45 out of 124). The rate of resistance to amoxicillin/clavulanic acid was 9% and 0.8%, using EUCAST and CLSI breakpoints respectively. For the 78 β-lactamase negative ampicillin-susceptible (BLNAS) isolates for which the Etest method indicated a high degree of susceptibility (MIC ≤ 1 mg/L), the disk diffusion method revealed resistance to ampicillin and amoxicillin/clavulanic acid in 33 cases (42%). Most common amino acid substitutions were Asn526Lys and Val547Ile, followed by Asp569Ser, Ala502Val, Asp350Asn, Met377Ile, Ile449Val, and Arg517His. The patterns observed were classified into six groups (IIa, IIb, IIc, IId, III-like, and miscellaneous). Continued characterization of both invasive and respiratory H. influenzae isolates is necessary in order to observe changes in the microbiology and epidemiology of this pathogen that could lead to clinical failure when treated by empirical antibiotic therapy.
Impact of revised CLSI breakpoints for susceptibility to third-generation cephalosporins and carbapenems among Enterobacteriaceae isolates in the Asia-Pacific region: results from the Study for Monitoring Antimicrobial Resistance Trends (SMART), 2002-2010.
Huang, Chi-Chang; Chen, Yao-Shen; Toh, Han-Siong; Lee, Yu-Lin; Liu, Yuag-Meng; Ho, Cheng-Mao; Lu, Po-Liang; Liu, Chun-Eng; Chen, Yen-Hsu; Wang, Jen-Hsien; Tang, Hung-Jen; Yu, Kwok-Woon; Liu, Yung-Ching; Chuang, Yin-Ching; Xu, Yingchun; Ni, Yuxing; Ko, Wen-Chien; Hsueh, Po-Ren
This study examined the rates of susceptibility to third-generation cephalosporins and carbapenems among Enterobacteriaceae isolates that had been obtained from patients with intraabdominal infections in the Asia-Pacific region as part of the Study for Monitoring Antimicrobial Resistance Trends (SMART). Susceptibility profiles obtained using 2009 Clinical and Laboratory Standards Institute (CLSI) breakpoints were compared with those obtained using the 2011 CLSI breakpoints. From 2002 to 2010, Escherichia coli and Klebsiella pneumoniae together accounted for more than 60% of the 13714 Enterobacteriaceae isolates analyzed during the study period. Extended-spectrum β-lactamase (ESBL) producers comprised 28.2% of E. coli isolates and 22.1% of K. pneumoniae isolates in the Asia-Pacific region, with China (55.6% and 33.7%, respectively) and Thailand (43.1% and 40.7%, respectively) having the highest proportions of ESBL producers. Based on the 2011 CLSI criteria, 77.2% of the Enterobacteriaceae isolates, 40.4% of ESBL-producing E. coli, and 25.2% of ESBL-producing K. pneumoniae isolates were susceptible to ceftazidime. Carbapenems showed in vitro activity against >90% of Enterobacteriaceae isolates in all participating countries, except for ertapenem in South Korea (susceptibility rate 82.2%). Marked differences (>5%) in susceptibility of ESBL-producing E. coli and K. pneumoniae isolates to carbapenems were noted between the profiles obtained using the 2009 CLSI criteria and those using the 2011 CLSI criteria. Continuous monitoring of antimicrobial resistance is necessary in the Asia-Pacific region.
Wu, Max T.; Westblade, Lars F.; Robertson, Amy E.; Wallace, Meghan A.; Burd, Eileen M.; Hindler, Janet A.
MIC results for 115 Staphylococcus intermedius group isolates are presented. Of these, 33% were methicillin resistant, among which 51.4% were susceptible to doxycycline, 29.7% to clindamycin, and 21.6% to trimethoprim-sulfamethoxazole. All of the isolates were susceptible to ceftaroline, daptomycin, linezolid, nitrofurantoin, quinupristin-dalfopristin, rifampin, tigecycline, and vancomycin. Of all the isolates, 82.6%, 67.8%, and 23.5% were susceptible to ciprofloxacin, erythromycin, and penicillin, respectively. No isolates harbored mupA or qacA/B genes, which suggested a lack of resistance to mupirocin or chlorhexidine. PMID:26962087
黄长征; 刘志香; 林能兴; 涂亚庭; 李家文; 张德美
Summary: In order to investigate the susceptibility of mixed infection of Ureaplasma Urealyticum(UU) and Mycoplasma Hominis (MH) to 7 kinds of antimicrobial agents and comparison with thatof UU infection in NGU patients, the in vitro susceptibility was determined by using microdilutionmethod. The positive results were analyzed. The results showed that the sequence of susceptibility to7 kinds of antimicrobial agents for both UU infection group and UU-MH mixed infection group wasalmost the same from the highest susceptibility to the lowest accordingly: Josamycin, Doxycycline,Minocycline, Sparfloxacin, Roxithromycin, Ofloxacin and Azithromycin. The total drug resistancerate for UU-MH mixed infection group (97.67 % ) was significantly higher than that for UU infec-tion group (44.67 %, P＜0. 01). The highest drug resistance rate in UU group and UU-MH mixedinfection group was 31. 33 % (Ofloxacin) and 90. 48 % (Azithromycin) respectively. UU-MHmixed infection showed an increased drug resistance and changes of drug resistance spectrum.
Martin, I; Sawatzky, P; Liu, G; Allen, V; Lefebvre, B; Hoang, L; Drews, S; Horsman, G; Wylie, J; Haldane, D; Garceau, R; Ratnam, S; Wong, T; Archibald, C; Mulvey, M R
Antimicrobial resistance profiles were determined for Neisseria gonorrhoeae strains isolated in Canada during 2010-2014. The proportion of isolates with decreased susceptibility to cephalosporins declined significantly between 2011 and 2014, whereas azithromycin resistance increased significantly during that period. Continued surveillance of antimicrobial drug susceptibilities is imperative to inform treatment guidelines.
Causse, M; Franco-Alvarez de Luna, F; García-Mayorgas, A D; Rodríguez, F C; Casal, M
Enterococcus faecalis is a pathogenic microorganism. The aim of this investigation was to study the antibiotic susceptibility of the strains isolated in Cordoba in a 20-month period (January 2004 to August 2005). Susceptibility rates to betalactamics were 98% to ampicillin and 99% to amoxicillin/clavulanic acid; high-dose aminoglycosides (streptomycin 1000 microg and gentamycin 500 microg) obtained 56% and 76%, respectively. We found no strains resistant to glycopeptides (vancomycin and teicoplanin) or to linezolid.
Gomez-Lopez, A.; Alastruey-Izquierdo, A.; Rodriguez, D.; Almirante, B.; Pahissa, A.; Rodriguez-Tudela, J. L.; Cuenca-Estrella, M.
We describe the prevalences and susceptibility profiles of two recently described species, Candida metapsilosis and Candida orthopsilosis, related to Candida parapsilosis in candidemia. The prevalences of these species (1.7% for C. metapsilosis and 1.4% for C. orthopsilosis) are significant. Differences observed in their susceptibility profiles could have therapeutic importance.
Gomez-Lopez, A; Alastruey-Izquierdo, A; Rodriguez, D; Almirante, B; Pahissa, A; Rodriguez-Tudela, J L; Cuenca-Estrella, M
We describe the prevalences and susceptibility profiles of two recently described species, Candida metapsilosis and Candida orthopsilosis, related to Candida parapsilosis in candidemia. The prevalences of these species (1.7% for C. metapsilosis and 1.4% for C. orthopsilosis) are significant. Differences observed in their susceptibility profiles could have therapeutic importance.
Bayramoğlu, Gülçin; Topkaya, Aynur E; Balıkcı, Ahmet; Aydın, Faruk
Frequency of invasive group A streptococcus (GAS) infections is increasing worldwide in recent 20 years. Serotypes responsible for these clinical manifestations and their antibiotic susceptibilities should be known in order to establish preventive measures and initiate appropriate treatment. This study was aimed to determine the serotypes, antibiotic susceptibilities and inducible clindamycin resistance among invasive GAS isolated between 2006-2009 period. A total of 22 GAS strains isolated from clinical samples [sterile body fluids (peritoneal, pleural, pericardial, joint and cerebrospinal fluids), blood, tissue biopsy] of the patients (14 male, 8 female; age range: 3-82 years, median age: 59) who admitted to Karadeniz Technical University Faculty of Medicine, Farabi Hospital located in Trabzon province (Eastern Black Sea Region of Turkey), between March 2006 and March 2009 were included in the study. GAS serotypes were determined by the investigation of serum opacity factors (SOF), T proteins and M proteins. SOF production was investigated by microplate method using human serum and SOF types were determined by SOF-inhibition test using specific antisera. T protein types were detected by agglutination method using polyvalent anti-T sera, and M serotypes were detected by capillary precipitation method using M antisera. Antimicrobial susceptibility tests were performed by disk-diffusion method according to CLSI recommendations. SOF were positive in 9 (41%) samples. Use of T antiserum yielded T (n= 8) and U (n= 7) types and M antiserum M1 (n= 4) and M2 (n= 3) types. The overall antibiotic susceptibility rate of the isolates was 68% (15/22) and overall resistance rate was 32% (7/22). All of the GAS strains were found susceptible to benzylpenicillin, ceftriaxone, vancomycin, levofloxacine and linezolid, however 9 (41%) were intermediate susceptible to tetracycline and 1 (4.5%) was intermediate susceptible to erythromycin. Four (18%) strains were found resistant to
Agueda C. Vargas
Full Text Available A campilobacteriose venérea bovina, ocasionada principalmente pelo Campylobacter fetus subsp. fetus e Campylobacter subsp. venerealis, é transmitida através do coito ou por inseminação com sêmen contaminado. O propósito deste estudo foi determinar a susceptibilidade in vitro de isolados de C. fetus subesp. venerealis a agentes antimicrobianos comumente utilizados para o tratamento clínico e de sêmen. Foram testadas duas cepas padrão, sendo uma de C. fetus subsp. fetus e outra de C. fetus subsp. venerealis, bem como 21 amostras de isolados clínicos de C. fetus subsp. venerealis. Os testes foram realizados conforme o método de Kirby-Bauer. A amostra padrão de C. fetus subsp. fetus demonstrou-se resistente à lincomicina, penicilina e ácido nalidíxico, enquanto a de C. fetus subsp. venerealis apresentou susceptibilidade a todos antimicrobianos testados, com exceção do ácido nalidíxico. Todas as amostras de C. fetus subsp. venerealis foram susceptíveis à amicacina, ampicilina, cefalotina, estreptomicina, gentamicina, penicilina e tetraciclina. Foi observada resistência de 42,86% à lincomicina e 4,76 % a enrofloxacina, e de 100% ao ácido nalidíxico. Ainda, 4,76% apresentaram susceptibilidade intermediária à enrofloxacina, neomicina e polimixina B e 9,52% à lincomicina. Os resultados evidenciaram a sensibilidade das amostras analisadas aos antimicrobianos comumente utilizados para o tratamento clínico e do sêmen.Venereal campylobacteriosis is associated with infection of Campylobacter fetus subsp. fetus and Campylobacter fetus subsp. venerealis. The etiological agent is transmitted by natural bull breeding or artificial insemination using contaminated semen. The present study aimed to determine the in vitro susceptibility of C. fetus subsp. venerealis isolates to antimicrobial drugs generally used in clinical and semen treatment. Reference strains of C. fetus subsp. fetus and C. fetus subsp. venerealis and 21 C. fetus
Wegener, Henrik Caspar; Watts, J.L.; Salmon, S.A.;
Exudative epidermitis or greasy pig syndrome is caused by the coagulase-variable staphylococcal species Staphylococcus hyicus. Treatment of this disease is problematic because of the limited number of antimicrobial agents available for this purpose. Thirteen antimicrobial agents were evaluated...... for their activities against 100 S. hyicus strains isolated from pigs with exudative epidermitis. Novobiocin was the most active compound tested, with an MIC for 90% of the strains tested (MIC(90)) of less than or equal to 0.06 mu g/ml. Enrofloxacin, ampicillin, and ceftiofur were the next most active compounds...... at ratios of 1:2 (lincomycin to spectinomycin) and 1:8 were more active, with MIC(90)s of 16.0 and 4.0 mu g/ml, respectively. These results indicate that novobiocin and sulfadiazine-trimethoprim were the most active compounds tested against the S. hyicus strains isolated from pigs with exudative epidermitis...
De Oliveira, A. P.; Watts, J. L.; Salmon, S. A.;
(123), Switzerland (69), United States (53), and Zimbabwe (6). The antimicrobial agents tested were penicillin, ampicillin, oxacillin, cephalothin, ceftiofur, amoxicillin + clavulanate, penicillin + novobiocin, enrofloxacin, premafloxacin, erythromycin, clindamycin, lincomycin, pirlimycin, neomycin......, lincomycin + neomycin, and sulfamethazine. The MIC90 for these antimicrobial agents for all strains were 0.5, 1.0, 1.0, 0.5, 1.0, less than or equal to 0.06, 0.125, 0.125, less than or equal to 0.0078, 0.5, 1.0, 16.0, 1.0, 2.0, 0.5, and 4.0 mu g/ml, respectively. Overall, only small variations between...
ter Laak, E A; Pijpers, A; Noordergraaf, J H; Schoevers, E C; Verheijden, J H
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 fi...
Glazkova, Slavyana; Golparian, Daniel; Titov, Leonid; Pankratova, Nataliya; Suhabokava, Nataliya; Shimanskaya, Irina; Domeika, Marius; Unemo, Magnus
Increased antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a global concern, and ultimately gonorrhoea may become untreatable. Nonetheless, AMR data from East-Europe are scarce beyond Russia, and no AMR data or other characteristics of gonococci have been reported from Belarus for more than 20 years. The aim was to describe the prevalence of AMR, and report molecular epidemiological characteristics of gonococci circulating in 2009 in Belarus. In a sample of 80 isolates, resistance prevalences to antimicrobials used for gonorrhoea treatment in Belarus were: Ceftriaxone 0%, spectinomycin 0%, azithromycin 17.3%, tetracycline 25.9%, ciprofloxacin 34.6% and erythromycin 59.2%. The isolates displayed no penA mosaic alleles, 38 porB gene sequences and 35 N. gonorrhoeae multiantigen sequence types, of which 20 have not been described before worldwide. Due to the high levels of antimicrobial resistance, only ceftriaxone and spectinomycin can be recommended for empirical treatment of gonorrhoea in Belarus according to WHO recommendations. Continuous gonococcal AMR surveillance in Eastern Europe is crucial. This is now initiated in Belarus using WHO protocols.
Chen, Chun-Yu; Chen, Wan-Ching; Chin, Shih-Chien; Lai, Yen-Hsueh; Tung, Kwong-Chung; Chiou, Chien-Shun; Hsu, Yuan-Man; Chang, Chao-Chin
Pets, including reptiles, have been shown to be a source of Salmonella infection in humans. Due to increasing popularity and variety of exotic reptiles as pets in recent years, more human clinical cases of reptile-associated Salmonella infection have been identified. However, limited information is available with regard to serotypes in different reptiles (turtles, snakes, and lizards) and antimicrobial resistance of Salmonella in pet reptiles. The current study was thus conducted to determine the prevalence of Salmonella colonization in pet reptiles. Salmonella organisms were isolated from 30.9% of 476 reptiles investigated. The isolation prevalences were 69.7% (23/33), 62.8% (27/43), and 24.3% (97/400) in snakes, lizards, and turtles, respectively. A total of 44 different Salmonella serovars were identified. Compared with S. Heron, Bredeney, Treforest, and 4,,12:i:-, S. Typhimurium isolates were resistant to many antimicrobials tested, and notably 61.1% of the isolates were resistant to cephalothin. The results indicated that raising reptiles as pets could be a possible source of Salmonella infection in humans, particularly zoonotic Salmonella serovars such as S. Typhimurium that may be resistant to antimicrobials.
杨启文; Janet A.Hindler; 徐英春
Antimicrobial susceptibility testing is an important tool for guiding rational use of antimicrobial agents in clinical settings.Proper use of antimicrobial susceptibility testing results requires clinicians and clinical microbiologists to have the knowledge of antimicrobial susceptibility testing and breakpoints,and have the ability to use pharmacokinetic and pharmacodynamic (PK/PD) principles to optimize antimicrobial therapy regimen.(Chin J Lab Med,2013,36:289-291)%抗菌药物敏感性试验是指导临床医生正确使用抗菌药物的重要工具.正确理解和运用药敏试验结果要求临床医生和临床微生物工作者具备药敏试验和药敏折点的相关知识,并能使用药代动力学/药效学原理优化抗菌药物治疗.(中华检验医学杂志,2013,36:289-291)
Ferreira, Débora Paula; Silva, Vânia Lúcia; Guimarães, Danielle Aparecida; Coelho, Cíntia Marques; Zauli, Danielle Alves Gomes; Farias, Luiz Macêdo; Carvalho, Maria Auxiliadora Roque; Diniz, Claudio Galuppo
Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG) are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110) and non-diarrheic (n=65) fecal samples from children aged 0–5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic), and 4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children. PMID:24031535
Ferreira, Débora Paula; Silva, Vânia Lúcia; Guimarães, Danielle Aparecida; Coelho, Cíntia Marques; Zauli, Danielle Alves Gomes; Farias, Luiz Macêdo; Carvalho, Maria Auxiliadora Roque; Diniz, Claudio Galuppo
Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG) are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110) and non-diarrheic (n=65) fecal samples from children aged 0-5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic), and 4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children.
Débora Paula Ferreira
Full Text Available Despite the importance of gastrointestinal diseases and their global distribution, affecting millions of individuals around the world, the role and antimicrobial susceptibility patterns of anaerobic bacteria such as those in the Bacteroides fragilis group (BFG are still unclear in young children. This study investigated the occurrence and distribution of species in the BFG and enterotoxigenic strains in the fecal microbiota of children and their antimicrobial susceptibility patterns. Diarrheic (n=110 and non-diarrheic (n=65 fecal samples from children aged 0-5 years old were evaluated. BFG strains were isolated and identified by conventional biochemical, physiological and molecular approaches. Alternatively, bacteria and enterotoxigenic strains were detected directly from feces by molecular biology. Antimicrobial drug susceptibility patterns were determined by the agar dilution method according to the guidelines for isolated bacteria. BFG was detected in 64.3% of the fecal samples (55% diarrheic and 80.4% non-diarrheic, and 4.6% were enterotoxigenic. Antimicrobial resistance was observed against ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol. The data show that these bacteria are prevalent in fecal microbiota at higher levels in healthy children. The molecular methodology was more effective in identifying the B. fragilis group when compared to the biochemical and physiological techniques. The observation of high resistance levels stimulates thoughts about the indiscriminate use of antimicrobial drugs in early infancy. Further quantitative studies are needed to gain a better understanding of the role of these bacteria in acute diarrhea in children.
Hannula, Minna; Hänninen, Marja-Liisa
The CmeABC efflux pump plays an important role in the antimicrobial resistance of Campylobacter jejuni and Campylobacter coli. The aim of this investigation was to study the effect of putative efflux pump inhibitors, phenyl-arginine-beta-naphthylamide (PAbetaN) and 1-(1-naphthylmethyl)-piperazine (NMP), as well as the effect of putative efflux pump inducers, sodium salicylate and sodium deoxycholate, on the MIC levels of erythromycin, ciprofloxacin, kanamycin, tetracycline and rifampicin for C. jejuni and C. coli. Our results indicated that susceptibility to erythromycin and rifampicin increased, respectively, 8- to 32- and 8- to 64-fold in the presence of PAbetaN and to a lesser extent in the presence of NMP. Salicylate produced a 2- to 4-fold increase in ciprofloxacin MIC values, whereas little effect was observed in the presence of deoxycholate.
Full Text Available Se determinaron los patrones de susceptibilidad de 50 cepas de A. butzleri mediante el método del E-test. Ninguna cepa fue resistente a gentamicina y tetraciclina, pero, hubo cepas resistentes a eritromicina (2% y ciprofloxacina (2%. Además, el 90 y el 98% de las cepas fueron resistentes a ampicilina y cloramfenicol respectivamente. Solamente dos de las 45 cepas ampicilina-resistentes fueron productoras de ß-lactamasa. Palabras clave: Arcobacter butzleri, susceptibilidad antimicrobiana, bacterias emergentes, E-test, ß-lactamasaThe susceptibility patterns of 50 A. butzleri strains to six antimicrobial agents were determined using the E-test method. No strain was found to be resistant to gentamicin and tetracycline, but two different strains (2% were resistant to erythromycin and ciprofloxacin. Ninety and 98% of the strains were resistant to ampicillin and chloramphenicol, respectively. Only two of the 45 ampicillin resistant strains were able to produce ß-lactamase.
Su, J Y; Chang, S C; Luh, K T; Hsieh, W C
The susceptibility of 46 pneumococcal isolates collected during October 1989 to May 1995 from National Taiwan University Hospital and Taipei Municipal Yang Ming Hospital was studied. Among these isolates, the resistant rate of penicillin G was 21.7%; the penicillin G-resistant strains were more frequently resistant than the penicillin-sensitive strains to other beta-lactam antimicrobial drugs. The minimum bactericidal concentrations (MBCs) of penicillin G for all isolates were equal to, or one dilution higher than, minimum inhibitory concentrations (MICs). Three strains were false positive for penicillin resistance among isolates of Streptococcus pneumoniae screened with oxacillin. On the other hand, resistance to penicillin G was often independent of resistance to erythromycin. Vancomycin was the most active agent tested.
Phongsamart, Wanatpreeya; Srifeungfung, Somporn; Chatsuwan, Tanittha; Nunthapisud, Pongpun; Treerauthaweeraphong, Vipa; Rungnobhakhun, Pimpha; Sricharoenchai, Sirintip; Chokephaibulkit, Kulkanya
To describe the trends in serotype distribution and antimicrobial susceptibility of S. pneumoniae causing invasive pneumococcal diseases (IPD) we tested 238 pneumococci isolates from normally sterile sites between 2009 and 2012 and compared these findings with previous data collected within our network. Serotyping was performed for 15 serotypes contained in the 7-,10-, 13-, and experimental 15-valent pneumococcal conjugate vaccines (PCV). The most common serotypes found were 6B (13.9%), 19A (12.6%), 14 (8.0%), 18C (5.9%), and 6A (3.8%); and 39.9% were non-PCV15 serotypes. One of 81 patients with available data had breakthrough infection with vaccine serotype (19F). There was a significant increase of serotype 19A among children ≤5 years (5.6% in 2000-2009 vs 18.3% in 2009-2012, P = 0.003). The all-age serotype coverage was 36.4%, 41.5%, 59.3%, and 59.7% for PCV7, PCV10, PCV13, and PCV 15, respectively. The corresponding coverage in children ≤5 years were 46.4%, 48.8%, 73.2%, and 73.2% respectively. High susceptibilities to penicillin (89.7%), cefotaxime (95.7%), cefditoren (90.2% by Spanish breakpoints), ofloxacin (97.9%), and levofloxacin (100%), but low to cefdinir (50.0%), cefditoren (45.1% by US-FDA breakpoints), macrolides (<50%), clindamycin (67.7%), tetracycline (41.4%), and trimethoprim-sulfamethoxazole (32.4%) were observed. Serotype 19A was less susceptible to penicillin (80.0 vs 91.2%, P = 0.046), cefditoren (66.7 vs 95.5% by Spanish breakpoints, P = 0.004), and tetracycline (9.1 vs 45.5%, P = 0.024) than non-19A isolates. These data emphasize the need for continued surveillance to monitor changes in serotypes as well as antimicrobial susceptibilities in order to guide strategies for prevention and treatment.
Full Text Available Abstract Background Ertapenem is a once-a-day carbapenem and has excellent activity against many gram-positive and gram-negative aerobic, facultative, and anaerobic bacteria. The susceptibility of isolates of community-acquired bacteremia to ertapenem has not been reported yet. The present study assesses the in vitro activity of ertapenem against aerobic and facultative bacterial pathogens isolated from patients with community-acquired bacteremia by determining and comparing the MICs of cefepime, cefoxitin, ceftazidime, ceftriaxone, ertapenem, piperacillin, piperacillin-tazobactam, ciprofloxacin, amikacin and gentamicin. The prevalence of extended broad spectrum β-lactamases (ESBL producing strains of community-acquired bacteremia and their susceptibility to these antibiotics are investigated. Methods Aerobic and facultative bacteria isolated from blood obtained from hospitalized patients with community-acquired bacteremia within 48 hours of admission between August 1, 2004 and September 30, 2004 in Chang Gung Memorial Hospital at Keelung, Taiwan, were identified using standard procedures. Antimicrobial susceptibility was evaluated by Etest according to the standard guidelines provided by the manufacturer and document M100-S16 Performance Standards of the Clinical Laboratory of Standard Institute. Antimicrobial agents including cefepime, cefoxitin, ceftazidime, ceftriaxone, ertapenem, piperacillin, piperacillin-tazobactam, ciprofloxacin, amikacin and gentamicin were used against the bacterial isolates to test their MICs as determined by Etest. For Staphylococcus aureus isolates, MICs of oxacillin were also tested by Etest to differentiate oxacillin-sensitive and oxacillin-resistant S. aureus. Results Ertapenem was highly active in vitro against many aerobic and facultative bacterial pathogens commonly recovered from patients with community-acquired bacteremia (128/159, 80.5 %. Ertapenem had more potent activity than ceftriaxone, piperacillin
Kosaka, Tadashi; Yamada, Yukiji; Kimura, Takeshi; Kodama, Mai; Fujitomo, Yumiko; Masaki, Nakanishi; Toshiaki, Komori; Keisuke, Shikata; Fujita, Naohisa
Respiratory quinolones (RQs) are broad-spectrum antimicrobial agents used for the treatment of a wide variety of community-acquired and nosocomial infections. However, bacterial resistance to quinolones has been on the increase. In this study, we investigated the predicted efficacy of RQs for various strains of 9 bacterial species clinically isolated at our university hospital using the Monte Carlo simulation (MCS) method based on pharmacokinetics/pharmacodynamics modeling. In addition, the influence of the patients' renal function on the efficacy of RQs was evaluated. We surveyed antimicrobial susceptibility testing of 9 bacterial species (n = number of strains) [Streptococcus pneumoniae (n = 15), Streptococcus pyogenes (n = 14), Streptococcus agalactiae (n = 19), methicillin-susceptible Staphylococcus aureus (MSSA) (n = 24), Escherichia coli (n = 35), Haemophilus influenzae (n = 17), Klebsiella pneumoniae (n = 14), Pseudomonas aeruginosa (n = 31), and Moraxella catarrhalis (n = 11)] to 4 RQs [garenoxacin (GRNX), levofloxacin (LVFX), sitafloxacin (STFX), and moxifloxacin (MFLX)]. We found that compared with the other RQs, Gram-positive cocci was most resistant to LVFX, and that the minimum inhibitory concentration (MIC₉₀) values for S. pneumoniae, S. pyogenes, S. agalactiae, and MSSA were high (2, 16, > 16, and 8 µg/mL, respectively). In regard to Gram-negative rods, the susceptibility of E. coli to RQs was found to be decreased, with the MIC₉₀ values of GRNX, LVFX, STFX, and MFLX being > 16, 16, 1, and 16 µg/mL, respectively. MCS revealed that the target attainment rate of the area under the unbound concentration-time curve divided by the MIC₉₀ (ƒ · AUC/MIC ratio), against S. pneumoniae was 86.9-100%, but against E. coli was low (52.1-66.2%). The ƒ · AUC/MIC target attainment rate of LVFX against S. pneumoniae, S. pyogenes, and S. agalactiae tended to decrease due to increased creatinine clearance, and that of LVFX and STFX against MSSA also
Hombach, M; Böttger, E C; Roos, M
Erroneous assignments of clinical isolates to the interpretative categories susceptible, intermediate and resistant can deprive a patient of successful antimicrobial therapy. The rate of major errors (ME) and very major errors (vME) is dependent on: (i) the precision/standard deviation (σ) of the antibiotic susceptibility testing (AST) method, (ii) the diameter distributions, (iii) clinical breakpoints, and (iv) the width of the intermediate zone. The European Committee on AST (EUCAST) has abandoned or decreased the intermediate zone for several drug/species combinations. This study focused on the effects of discontinuing the intermediate category on the rate of interpretation errors. In total, 10,341 non-duplicate clinical isolates were included in the study. For susceptibility testing the disc diffusion method was used. Error probabilities were calculated separately for diameter values flanking the interpretative category borders. Error probabilities were then applied to the actual numbers of clinical isolates investigated and expected rates of ME and vME were calculated. Applying EUCAST AST guidelines, significant rates of ME/vME were demonstrated for all drug/species combinations without an intermediate range. Virtually all ME/vME expected were eliminated in CLSI guidelines that retained an intermediate zone. If wild-type and resistant isolates are not clearly separated in susceptibility distributions, the retaining of an intermediate zone will decrease the number of ME and vME. An intermediate zone of 2-3 mm avoids almost all ME/vME for most species/drug combinations depending on diameter distributions. Laboratories should know their epidemiology settings to be able to detect problems of individual species/drug/clinical breakpoint combinations and take measures to improve precision of diameter measurements.
Full Text Available Abstract Background Antimicrobial resistance (AMR in Neisseria gonorrhoeae is a major public health concern worldwide. In Vietnam, knowledge regarding N. gonorrhoeae prevalence and AMR is limited, and data concerning genetic characteristics of N. gonorrhoeae is totally lacking. Herein, we investigated the phenotypic AMR (previous, current and possible future treatment options, genetic resistance determinants for extended-spectrum cephalosporins (ESCs, and genotypic distribution of N. gonorrhoeae isolated in 2011 in Hanoi, Vietnam. Methods N. gonorrhoeae isolates from Hanoi, Vietnam isolated in 2011 (n = 108 were examined using antibiograms (Etest for 10 antimicrobials, Neisseria gonorrhoeae multi-antigen sequence typing (NG-MAST, and sequencing of ESC resistance determinants (penA, mtrR and penB. Results The levels of in vitro resistance were as follows: ciprofloxacin 98%, tetracycline 82%, penicillin G 48%, azithromycin 11%, ceftriaxone 5%, cefixime 1%, and spectinomycin 0%. The MICs of gentamicin (0.023-6 mg/L, ertapenem (0.002-0.125 mg/L and solithromycin (penA mosaic alleles were found, however, 78% of the isolates contained an alteration of amino acid A501 (A501V (44% and A501T (34% in the encoded penicillin-binding protein 2. A single nucleotide (A deletion in the inverted repeat of the promoter region of the mtrR gene and amino acid alterations in MtrR was observed in 91% and 94% of the isolates, respectively. penB resistance determinants were detected in 87% of the isolates. Seventy-five different NG-MAST STs were identified, of which 59 STs have not been previously described. Conclusions In Vietnam, the highly diversified gonococcal population displayed high in vitro resistance to antimicrobials previously recommended for gonorrhoea treatment (with exception of spectinomycin, but resistance also to the currently recommended ESCs were found. Nevertheless, the MICs of three potential future treatment options were low. It is
Bobenchik, April M; Deak, Eszter; Hindler, Janet A; Charlton, Carmen L; Humphries, Romney M
Vitek 2 (bioMérieux Inc., Durham, NC) is a widely used commercial antimicrobial susceptibility test system. We compared the MIC results obtained using the Vitek 2 AST-GN69 and AST-XN06 cards to those obtained by CLSI broth microdilution (BMD) for 255 isolates of Enterobacteriaceae, including 25 isolates of carbapenem-resistant Enterobacteriaceae. In total, 25 antimicrobial agents were examined. For 10 agents, the MIC data were evaluated using two sets of breakpoints: (i) the Vitek 2 breakpoints, which utilized the 2009 FDA breakpoints at the time of the study and are equivalent to the 2009 CLSI M100-S19 breakpoints, and (ii) the 2014 CLSI M100-S24 breakpoints. There was an overall 98.7% essential agreement (EA). The categorical agreement was 95.5% (CA) using the Vitek 2 breakpoints and 95.7% using the CLSI breakpoints. There was 1 very major error (VME) (0.05%) observed using the Vitek 2 breakpoints (cefazolin) and 8 VMEs (0.5%) using the CLSI breakpoints (2 each for aztreonam, cefepime, and ceftriaxone, and 1 for cefazolin and ceftazidime). Fifteen major errors (MEs) (0.4%) were noted using the Vitek 2 breakpoints and 8 (0.5%) using the CLSI breakpoints. Overall, the Vitek 2 performance was comparable to that of BMD for testing a limited number of Enterobacteriaceae commonly isolated by clinical laboratories. Ongoing studies are warranted to assess performance in isolates with emerging resistance.
Chen, Lei; Song, Yajing; Wei, Zigong; He, Hongkui; Zhang, Anding; Jin, Meilin
Streptococcus suis (S. suis) is an emerging zoonotic pathogen causing significant economic losses in the swine industry. Here, we investigated the antimicrobial susceptibility, associated antibiotic-resistant determinants and sequence type (ST) of S. suis isolates from diseased pigs in China from 2008 to 2010. Serotype 2 was the most frequently observed strain (n=95) among the 106 S. suis strains collected, followed by serotypes 3 (n=3), 5 (n=3), 4 (n=2), 7 (n=1), 11 (n=1) and 28 (n=1). Multilocus sequence typing analysis revealed that ST1 (n=21) and ST7 (n=74) were the predominant STs, and serotype 2 was found to be significantly correlated with ST7 (P=0.017, Fisher's exact test) and CC1 (P=0.024, Fisher's exact test). The antimicrobial susceptibility results indicated that the antibiotic resistance rate was highest for tetracycline (99.1%), followed by azithromycin (68.9%), erythromycin (67.9%), clindamycin (67.9%), trimethoprim/sulfamethoxazole (16%), levofloxacin (2.8%), chloramphenicol (1.9%), cefaclor (0.9%) and ceftriaxone (0.9%). Antibiotic-resistant genes tet(M), tet(O), tet(O/W/32/O), tet(O/32/O), tet(S), tet(W), tet(L), tet(40), erm(B), mef(A/E) and msr(D) could be detected, and several tandem organizations of antibiotic resistance genes were also found in this study. In conclusion, S. suis strains isolated from diseased pigs in China were less diverse and multi-drug resistant.
María del Pilar Sánchez Bonilla
Full Text Available Objective: To determine the antimicrobial presence and susceptibility of the coagulase-negative staphylococci group (ECN, for its initials in Spanish in some cattle farms from Tolima, Colombia. Materials and methods: Using the California test for the diagnosis of mastitis (CMT, for its initials in Spanish, 484 quarters belonging to 121 cows from five small production ranches from a region of central Tolima were evaluated. CMT positive samples were cultivated for bacterial isolation. The ECN found were tested for susceptibility to the antibiotics. The results were analyzed with descriptive statistics. Results: 252 (52% quarters did not show any type of reaction to the CMT, nor did they show any clinical signs of mastitis, therefore they were considered free of the disease. From the quarters, 73 (15% turned positive for CMT and bacteriological culture. From these, 36 strains of ECN were isolated (7.4% of the total of quarters; S. aureus-ECP, 28 (5.8%; Streptococcus spp., 6 (1.2%.; Escherichia coli, 2 (0.4%, and Klebsiella pneumoniae, 2 (0.2%. The clinical and subclinical mastitis in the quarter occurred in 1.4% and 13.6%, respectively. In 5 (1.0% of the quarters, clinical mastitis caused by ECN was found and subclinical mastitis in 31 (6.4%. 61% of the ECN strains were resistant to penicillin, and 58%, to tetracycline; 97% were sensitive to cefoperazone. Conclusion: The ECN group, considered a global emergent of mastitis, is evidenced with high frequency in ranches from Tolima, Colombia, causing clinical and subclinical mastitis with varied response to antimicrobials.
Salmonellosis is one of the most important foodborne diseases affecting humans. To characterize the relationship between Salmonella causing human infections and their food animal reservoirs, we compared pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility patterns of non-typhoida...
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.
Idelevich, Evgeny A; Schüle, Isabel; Grünastel, Barbara; Wüllenweber, Jörg; Peters, Georg; Becker, Karsten
Briefly incubated agar cultures from positive blood cultures were used for antimicrobial susceptibility testing (AST) by Vitek 2. The cultivation time until inoculation was 3.8 h for Gram-positive cocci and 2.4 h for Gram-negative rods. The error rates were low, providing early and reliable AST without additional time or cost expenditure.
Guardabassi, Luca; Hedberg, Sandra; Jessen, Lisbeth Rem
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......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...
Zottola, T; Montagnaro, S; Magnapera, C; Sasso, S; De Martino, L; Bragagnolo, A; D'Amici, L; Condoleo, R; Pisanelli, G; Iovane, G; Pagnini, U
The prevalence of Salmonella spp. infection was determined in 499 wild boars harvested during the 2010-2011 and 2011-2012 hunting seasons in the Latium Region of Italy. We conducted a microbiological assessment on faeces collected at slaughter and we examined serum samples for the presence of antibodies to Salmonella spp. by ELISA assay. Out of 383 serum samples examined, 255 (66.5%) were positive for Salmonella spp. antibodies. Overall, 10.8% (54/499) of the animals were positive by microbiological assessment. The Salmonellae most frequently isolated were S. enterica subsp. salamae II (24%), S. enterica subsp. Diarizonae III b (12.9%), S. enterica subsp. houtenae IV (11.1%) and S. Fischerhuette (7.4%); less common Salmonella isolates included S. Veneziana (5.5%), S. Napoli (5.5%), S. Kottbus (5.5%), S. Thompson (5.5%), S. enterica subsp. arizonae III a (3.7%), S. Toulon (3.7%), S. Burgas (1.8%), S. Tennelhone (1.8%), S. Ferruch (1.8%), S. choleraesuis (1.8%), S. Paratyphi (1.8%), S. Stanleyville (1.8%), S. Typhimurium (1.8%) and S. enterica subsp. enterica 4,5,12:1:- (1.8%). These isolates were tested against 16 antimicrobial agents and exhibited resistance to sulphonamides (92.5%), sulphonamides and thrimetroprim (14.8%), colistin (14.8%), streptomycin (18.5%), gentamycin (5.5%), tetracycline (5.5%), ceftiofur (3.7%), cefazoline (1.8%), cefotaxime (1.8%), nalidixic acid (1.8%), amoxicillin and clavulanic acid (1.8%) and ampicillin (3.7%). Our data, the first collected on this species in Italy, suggest that European wild boars are frequent carriers of antimicrobial-resistant Salmonellae and are likely involved in the transmission of antimicrobial resistance throughout the environment.
Lemes, Raquel M.L.; Lyon, Juliana P.; Moreira, Leonardo M.; de Resende, Maria Aparecida
The aim of the present study was to evaluate the antifungal susceptibility profile of Trichosporon species isolated from different sources employing the Clinical and Laboratory Standards Institute (CLSI) method and E-test method. Thirty-four isolates of Trichosporon spp. and six CBS reference samples were tested for their susceptibility to Amphotericin B, 5-flucytosine, Fluconazole, Itraconazole, Voriconazole and Terbinafine. All species showed high Minimun Inhibitory Concentrations (MIC) for Itraconazole and susceptibility to Fluconazole, The comparison among the results obtained by the CLSI method and E-test revealed larger discrepancies among 5-flucytosine and Itraconazole. The present work provides epidemiological data that could influence therapeutic choices. Furthermore, the comparison between different methodologies could help to analyze results obtained by different laboratories. PMID:24031497
Raquel M.L. Lemes
Full Text Available The aim of the present study was to evaluate the antifungal susceptibility profile of Trichosporon species isolated from different sources employing the Clinical and Laboratory Standards Institute (CLSI method and E-test method. Thirty-four isolates of Trichosporon spp. and six CBS reference samples were tested for their susceptibility to Amphotericin B, 5-flucytosine, Fluconazole, Itraconazole, Voriconazole and Terbinafine. All species showed high Minimun Inhibitory Concentrations (MIC for Itraconazole and susceptibility to Fluconazole, The comparison among the results obtained by the CLSI method and E-test revealed larger discrepancies among 5-flucytosine and Itraconazole. The present work provides epidemiological data that could influence therapeutic choices. Furthermore, the comparison between different methodologies could help to analyze results obtained by different laboratories.
Vulfson, L.; Pedersen, Karl; Chriel, M.;
, the most frequent being O2 (11.0%). O78 (11.0%), O153 (7.1%). O25 (5.7%). O6 (4.8%). and O15 (4.8%). but diarrhoea was not associated with specific serogroups. All isolates were sensitive to enrofloxacin, neomycin, gentamicin and colistin. In contrast, considerable variations in susceptibility were found...
Full Text Available Background: To assess the distribution and resistance of the pathogens responsible for septic arthritis and osteomyelitis over a 10 years period in children admitted to Children's Medical Center Hospital, Tehran, Iran.Methods: Microbiologic and clinical presentation reports from 145 cases of septic arthritis and osteomyelitis from March 1995 to February 2005 were retrospectively reviewed. Results: Of 145 cases, 71(49% had positive culture: 71.8%(51/71 of organisms were isolated from synovial fluid alone, 8.4%(6/71 from blood culture alone and 19.7% (14/71 from both synovial fluids and blood cultures. Staphylococcus aureus was the most common pathogen isolated, making up 60.5% of all positive cultures, followed by Klebsiella spp. (14% and coagulase-negative staphylococci (8.4%. Thirty eight percent of S. aureus and 84% of coagulase-negative staphylococci isolates were resistant to cloxacillin. All isolates of S. aureus were susceptible to clindamycin and also, 89% were susceptible to vancomycin. Among Klebsiella spp., amikacin was shown to be very effective, with susceptibility rates of 100%. Haemophilus influenzae was identified in only 2% of all patients.Conclusion: The present study highlights the importance of characterizing the etiology and antibiotic susceptibility of organisms causing septic arthritis or osteomylitis in children.
Takahashi, Satoshi; Kurimura, Yuichiro; Hashimoto, Jiro; Uehara, Teruhisa; Hiyama, Yoshiki; Iwasawa, Akihiko; Nishimura, Masahiro; Sunaoshi, Kenichi; Takeda, Koichi; Suzuki, Nobukazu; Tsukamoto, Taiji
The spread of antimicrobial-resistant Neisseria gonorrhoeae worldwide is a critical issue in the control of sexually transmitted infections. The purpose of this study was to clarify recent trends in the susceptibility of N. gonorrhoeae to various antimicrobial agents and to compare these data with our previous data. Minimum inhibitory concentrations (MICs) of various antimicrobial agents were determined in N. gonorrhoeae strains clinically isolated from male gonococcal urethritis. In addition, amino acid sequencing of penicillin-binding protein (PBP) 2, encoded by the penA gene, was analyzed so that genetic analysis of mosaic PBP 2 could clarify the susceptibility of the strains to cefixime and other cephalosporins. The susceptibility rate for ceftriaxone, cefodizime, and spectinomycin, agents whose use is recommended by the guideline of the Japanese Society of Sexually Transmitted Infections (JSSTI), was 100 %. The susceptibility rates of the strains to penicillin G and ciprofloxacin were lower than those in previous reports. Mosaic PBP 2 structures were detected in 51.9 % of the strains and the MICs of the strains with the mosaic PBP 2 to cefixime were much higher than those of the strains without the mosaic PBP 2. In the clinical situation, the treatment regimen recommended by the JSSTI remains appropriate; however, the susceptibility to cephalosporins should be intensively surveyed because strains with mosaic PBP 2 were commonly detected.
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.
Peterson, Ross; Hariharan, Harry; Matthew, Vanessa; Chappell, Sam; Davies, Rob; Parker, Regina; Sharma, Andravindra
Samples of intestine and hepatopancreas from 65 blue land crabs (Cardisoma guanhumi), a crustacean commonly consumed as a food item in Grenada, were collected from six geographic sites in Grenada and tested for Salmonella by enrichment and selective culture. The individual animal prevalence of Salmonella based on isolation was 17% (11 of 65), and all infected crabs were from three of the six sampled locations. Isolates were identified by serotyping as Salmonella enterica serovars Saintpaul (n = 6), Montevideo (n = 4), and Newport (n = 1). The intestines of all 11 infected crabs were positive for Salmonella, but only 7 of 11 hepatopancreas samples were positive for Salmonella, and these isolates were the same serovar as isolated from the matching intestine. These three Salmonella serovars are known to cause human illness in many countries, and in the Caribbean Salmonella Saintpaul has been frequently isolated from humans. In a disc diffusion assay, all isolates were susceptible to all 11 drugs tested: amoxicillin-clavulanic acid, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, imipenem, neomycin, streptomycin, tetracycline, and trimethoprim-sulfamethoxazole. To our knowledge, this report is the first concerning isolation and antimicrobial susceptibilities of Salmonella serotypes from the blue land crab.
Sattar, Sampurna; Song, Yan; Anstead, James A; Sunkar, Ramanjulu; Thompson, Gary A
Aphis gossypii resistance in melon (Cucumis melo) is due to the presence of a single dominant virus aphid transmission (Vat) gene belonging to the nucleotide-binding site leucine-rich repeat family of resistance genes. Significant transcriptional reprogramming occurs in Vat(+) plants during aphid infestation as metabolism shifts to respond to this biotic stress. MicroRNAs (miRNAs) are involved in the regulation of many biotic stress responses. The role of miRNAs was investigated in response to aphid herbivory during both resistant and susceptible interactions. Small RNA (smRNA) libraries were constructed from bulked leaf tissues of a Vat(+) melon line following early and late aphid infestations. Sequence analysis indicated that the expression profiles of conserved and newly identified miRNAs were altered during different stages of aphid herbivory. These results were verified by quantitative polymerase chain reaction experiments in both resistant Vat(+) and susceptible Vat(-) interactions. The comparative analyses revealed that most of the conserved miRNA families were differentially regulated during the early stages of aphid infestation in the resistant and susceptible interactions. Along with the conserved miRNA families, 18 cucurbit-specific miRNAs were expressed during the different stages of aphid herbivory. The comparison of the miRNA profiles in the resistant and susceptible interactions provides insight into the miRNA-dependent post-transcriptional gene regulation in Vat-mediated resistance.
Full Text Available New molecular identification techniques and the increased number of patients with various immune defects or underlying conditions lead to the emergence and/or the description of novel species of human and animal fungal opportunistic pathogens. Antifungal susceptibility provides important information for ecological, epidemiological and therapeutic issues. The aim of this study was to assess the potential risk of the various species based on their antifungal drug resistance, keeping in mind the methodological limitations. Antifungal susceptibility profiles to the five classes of antifungal drugs (polyens, azoles, echinocandins, allylamines and antimetabolites were determined for 1698 yeast reference strains belonging to 992 species (634 Ascomycetes and 358 Basidiomycetes. Interestingly, geometric mean minimum inhibitory concentrations (MICs of all antifungal drugs tested were significantly higher for Basidiomycetes compared to Ascomycetes (p<0.001. Twenty four strains belonging to 23 species of which 19 were Basidiomycetes seem to be intrinsically "resistant" to all drugs. Comparison of the antifungal susceptibility profiles of the 4240 clinical isolates and the 315 reference strains belonging to 53 shared species showed similar results. Even in the absence of demonstrated in vitro/in vivo correlation, knowing the in vitro susceptibility to systemic antifungal agents and the putative intrinsic resistance of yeast species present in the environment is important because they could become opportunistic pathogens.
Udayagiri Venkata Rohini
Full Text Available Background: Asymptomatic bacteriuria (ASB is defined as the presence of actively multiplying bacteria, which is greater than 105/ ml of urine within the urinary tract excluding the distal urethra, at a time when the patient has no symptoms of UTI. Untreated and undiagnosed ASB is associated with adverse maternal and perinatal outcomes. The objective was to determine the profile, prevalence, microbiological isolates with susceptibility, and risk factors of ASB among pregnant women attending an antenatal clinic at a tertiary care hospital, Andhra Pradesh, India. Methods: A prospective cross sectional study with 200 pregnant women was conducted for a period of 3 months from January to March 2016. The mid- stream urine specimen was collected and processed from all the cases and social and baseline obstetric data was collected. The isolates from all the cases of ASB were identified by standard biochemical tests. Antimicrobial susceptibility was performed by Kirby- Bauer disc diffusion method and interpreted as per CLSI guidelines. Results: Prevalence of ASB in our study was 30.5%, mean age of the cases was 27.3± 2.9 years. ASB was most common in 25- 30 year’s age group, during 3rd trimester and among multiparous and multigravidae. Previous history of UTI, pre-eclampsia was having significant association among cases with ASB. Escherichia coli was the predominant isolate in the study followed by K. pneumoniae, CONS (Coagulase-Negative Staphylococci, Staphylococcus aureus, citrobacter and Enterococci. Conclusions: Undiagnosed and untreated asymptomatic bacteriuria is associated with complications during pregnancy. Hence routine screening of antenatal women during all trimesters must be considered in preventing the complications and adverse foetal outcomes particularly with known risk factors like increasing age, multiparity and previous history of UTI.
Latika J Shah
Full Text Available Introduction: Urinary tract infections (UTIs are counted among the most common infections in humans. In spite of the availability and use of the antimicrobial drugs, UTIs caused by bacteria have been showing increasing trends. The extensive and inappropriate use of antimicrobial agents has invariably resulted in the development of antibiotic resistance which, in recent years, has become a major problem worldwide. Materials and Methods: Patients diagnosed clinically as UTI during the study period were included in the study. Urine sample of these patients were tested for Culture. All positive cultures were tested for antibiotic susceptibility. Results: Out of total 232 patients, Isolates were detected in 177 (76.29% samples. Out of these, 137 (77.40% were female. Most common organism found positive was Escherichia Coli. E. coli was highly sensitive to Amikacin and Nitrofurantoin. Whereas, E.coli was highly resistant to Ampicillin and Nalidixic acid. Antibiotic sensitivity pattern of Klebsiella and Acinitobacter shows that they were also highly sensitive to Amikacin. Klebsiella and Acinobacter were highly resistant to Ampicillin and Gentamycin. Conclusion: The pattern of resistance to commonly used antibiotics for treating UTI alerts us against indiscriminate usage of antibiotics [Natl J Med Res 2015; 5(1.000: 71-74
Gattringer, Rainer; Sauermann, Robert; Lagler, Heimo; Stich, Karin; Buxbaum, Astrid; Graninger, Wolfgang; Georgopoulos, Apostolos
A total of 341 clinical isolates of Streptococcus pyogenes from Vienna, Austria and three Hungarian cities were tested for susceptibility to four macrolides and 12 other antibiotics. All isolates were fully susceptible to penicillin and the other beta-lactams tested. A high level of tetracycline resistance was found in Austria (26.7%) and in Hungary (30.5%). The rate of resistance to erythromycin, clarithromycin and azithromycin was 4.7% in Vienna and 3.7% in the Hungarian communities. In both countries, the MIC(90) values of erythromycin and clarithromycin were 0.12 mg/L and the MIC(90) of josamycin was 0.5mg/L. The M phenotype of resistance conferred by the mefA genes was predominant (n = 9) among the macrolide-resistant isolates (n = 14).
Hartzen, S H; Andersen, L P; Bremmelgaard, A;
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...
Antúnez A., Oscar; Laboratorio de Medicina Veterinaria Preventiva, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima; Calle E., Sonia; Laboratorio de Medicina Veterinaria Preventiva, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima; Morales C., Siever; Laboratorio de Medicina Veterinaria Preventiva, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima; Falcón P., Néstor; Laboratorio de Medicina Veterinaria Preventiva, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima Perú.; Pinto J., Chris; Laboratorio de Medicina Veterinaria Preventiva, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima
The canine bacterial dermatitis, commonly known as pyoderma is one of the main skin diseases in the veterinary practice. The present retrospective study had the objective to determine the frequency of the bacteriological agents involved with the disease and the antibiotics that show better antimicrobiobial susceptibility. Laboratory records of bacterial isolation and antibiogram of the Laboratory of Bacteriology of the Veterinary Medicine Faculty, San Marcos University, Lima, were analyzed. S...
Full Text Available Escherichia coli is one of the most common pathogens in nosocomial and community-acquired infections in humans. Fosfomycin is a broad-spectrum antibiotic which inhibits peptidoglycan synthesis responsible for bacterial cell wall formation. Although low, the exact E. coli susceptibility to fosfomycin as well as the mechanisms of resistance in the population from Mainland China are mostly unknown. 1109 non-duplicate clinical E. coli strains isolated from urine, sputum, blood and pus samples in 20 widely dispersed tertiary hospitals from Mainland China were collected from July 2009 to June 2010, followed by determination of minimum inhibitory concentrations of fosfomycin. Detection of the murA, glpT, uhpT, fosA, fosA3 and fosC genes was performed in fosfomycin non-susceptible E. coli strains and conjugation experiments were employed to determine the mobility of fosA3 gene. In this study, 7.8% (86/1109 E. coli strains were fosfomycin non-susceptible. Amino acid substitutions in GlpT and MurA were found in six and four E.coli strains, respectively, while the uhpT gene was absent in eighteen E.coli strains. Twenty-nine isolates carried the transferable plasmid with the fosA3 gene at high frequencies of around 10(-6 to 10(-7 per donor cell in broth mating. The majority of isolates were susceptible to fosfomycin, showing that the drug is still viable in clinical applications. Also, the main mechanism of E. coli resistance in Mainland China was found to be due to the presence of the fosA3 gene.
Aarestrup, Frank Møller; Tvede, Michael
A total of 65 toxigenic Clostridium difficile strains isolated from patients with antibiotic-associated diarrhea were tested for susceptibility to avilamycin, flavomycin, monensin, and salinomycin. Except for flavomycin the substances showed in vitro efficacy comparable to reports of the currentl...... most commonly used drugs for treatment of C. difficile. This indicates that these old compounds may be useful for the treatment of C. difficile infections in man and perhaps for other bacterial causes of diarrhea....
Sallam, Khalid Ibrahim; Abd-Elghany, Samir Mohammed; Elhadidy, Mohamed; Tamura, Tomohiro
The emergence of livestock-associated methicillin-resistant Staphylococcus aureus (MRSA) in food-producing animals is of increasing interest, raising questions about the presence of MRSA in food of animal origin and potential sources of transmission to humans via the food chain. In this study, the prevalence, molecular characterization, virulence factors, and antimicrobial susceptibility patterns of MRSA isolates from 200 retail raw chicken samples in Egypt were determined. MRSA was detected by positive amplification of the mecA gene in 38% (76 of 200) of chicken samples analyzed. This represents a potential public health threat in Egypt, as this contamination rate seems to be the highest among other studies reported worldwide. Furthermore, genes encoding α-hemolysin (hla) and staphylococcal enterotoxins (sea, seb, and sec) were detected in all of the 288 MRSA isolates. Nonetheless, none of the strains tested carried tst, the gene encoding toxic shock syndrome toxin 1. Antimicrobial resistance of MRSA isolates was most frequently detected against penicillin (93.4%), ampicillin (88.9%), and cloxacillin (83.3%). These results suggest that retail chicken might be a significant potential source for transmission of multidrug-resistant and toxigenic S. aureus in Egypt. This underlines the need for stricter hygienic measures in chicken production in Egypt to minimize the risk of transmission of these strains to consumers. To the best of our knowledge, this is the first study that reports the isolation and molecular characterization of MRSA in retail chicken samples in Egypt.
Full Text Available BACKGROUND: Acinetobacter are the “superbugs” of the modern hospital environment causing significant proportion of infections and in particular nosocomial infections with high mortality rates. The aim of this study was to isolate Acinetobacter species from clinical specimens and to study the antimicrobial susceptibility pattern of Acinetobacter isolates. MATERIAL AND METHODS: Two hundred and four clinical isolates of Acinetobacter species were processed for species identification by standard microbiological procedures. Antimicrobial susceptibility of these isolates was performed by Kirby-Bauer disc diffusion method. RESULTS: Out of 204 Acinetobacter isolates, 125(61.27% isolates were from ICU and 79(38.72% were from general wards. A baumannii was the most common species isolated (74.50%, followed by A.lwoffii (24.50% and A.haemolyticus (0.98%. A.baumannii showed maximum sensitivity to IPM (52.63% followed by MRP(36.18%, AK(28.28%, PIT(26.31%, TCC(21.71%, CIP(21.05% G(17.76% and COT(05.26%. Maximum resistance was observed to CTX(1.31% followed by CAZ(1.97%, CTR(1.97% and CPM(1.97% respectively. A.lwoffii showed maximum sensitivity to IPM(94% followed by AK(90%, and MRP(84%. Statistically significant difference (p value <0.001 was noticed between antibiotic resistance of A.baumannii and A.lwoffii. CONCLUSION: Continued surveillance of drug resistant strains in ICUs, combined with preventive measures remains absolutely essential to prevent or limit the spread of Acinetobacter species in hospital.
Zidaric, Valerija; Rupnik, Maja
Increased sporulation and antibiotic resistance have been proposed to be associated with certain Clostridium difficile epidemic strains such as PCR ribotype 027. In this study we examined these properties in another widespread PCR ribotype, 014/020, in comparison to prevalent PCR ribotype 002 and a group of rarely represented PCR ribotypes. Highest sporulation was observed in 014/020 strains at 24 h, while after 72 h PCR ribotype 002 and rare PCR ribotypes formed higher total number of spores. PCR ribotype 014/020 strains exhibited slightly higher resistance to tested antimicrobials, followed by group of rare PCR ribotypes and less common PCR ribotype 002. Neither sporulation properties nor antibiotic resistance clearly differed in endemic and rare strains.
Jovanović, Milica; Milošević, Branko; Tošić, Tanja; Stevanović, Goran; Mioljević, Vesna; Inđić, Nikola; Velebit, Branko; Zervos, Marcus
In this study the distribution of species and antimicrobial resistance among vancomycin resistant enterococci (VRE) recovered from clinical specimens obtained from five hospitals in Belgrade was analyzed. Strains were further characterized by pulsed-field gel electrophoresis (PFGE). Polymerase chain reaction (PCR) was used to investigate the presence of vanA and vanB genes and pathogenicity factor genes. Identification of 194 VRE isolates revealed 154 Enterococcus faecium, 21 Enterococcus faecalis, 10 Enterococcus raffinosus and 9 Enterococcus gallinarum. This study revealed existence of 8 major clones of VRE. PCR determined vanA gene to be present in all of the VRE studied. Esp and hyl genes were present in 29.22% and 27.92% of E. faecium, respectively, and in 76.19% and 0 of E. faecalis, respectively. Esp and hyl genes were not found more frequently in members of predominant clones of E. faecium than in single isolates; nor was their presence connected to invasiveness.
Jemsek, J G; Martin, R R; Greenberg, S B; Gentry, L O
A kinetic killing-curve method, designed to mimic several aspects of clinical therapy in endocarditis, was used to test 10 strains of Haemophilus parainfluenzae against 28 antibiotic regimens. In an effort to simulate changing in vivo levels of antibiotic in serum, concentrations of three penicillins, three cephalosporins, gentamicin, and chloramphenicol were sequentially adjusted over a 12-hr period. Against six beta-lactamase-negative strains, gentamicin in combination with penicillin or cephalosporin invariably resulted in an additive or synergistic effect. Chloramphenicol and a penicillin or cephalosporin usually displayed an indifferent effect, but chloramphenicol was often antagonistic when combined with gentamicin. With four beta-lactamase-positive strains, variable responses were noted to penicillin-aminoglycoside combinations; cephalosporin-aminoglycoside combinations were usually synergistic. This dynamic approach to killing-curve studies may be more appropriate than a static system for in vitro examination of the effect of antimicrobial combinations against selected organisms.
Kim, Dae Ho; Chung, Yeon Soo; Park, Young Kyung; Yang, Soo-Jin; Lim, Suk Kyung; Park, Yong Ho; Park, Kun Taek
Antimicrobial-resistant (AR) enterococci have emerged as leading nosocomial pathogens. Transmission of AR Enterococci from animals to humans has been demonstrated. However, there is limited information on the transmission of enterococci from horses to humans. To address this issue, we characterized 260 enterococci isolated from horse-associated samples in Korea in 2013 based on their AR profiles and virulence traits. AR profiling revealed an average ratio of AR enterococci of 23.8%. Seven isolates (2.7%) were multidrug-resistant Enterococcus faecalis. Most tetracycline-resistant enterococci harbored either tetM or tetL or both genes; genes conferring resistance to other antimicrobials were detected at low rates. Biofilm formation and gelatinase activity were observed in 51.1% and 47.7% of isolates, respectively; most were E. faecalis harboring the gelE gene. Evidence of transmission of AR enterococci between horses and their environments was provided by pulsed-field gel electrophoresis, and highlights the risk of AR enterococcus transmission to horse riders and handlers through close contact.
Full Text Available Resistant bacteria in animal can be spread to environment and to humans. Poultry feed and infections caused by Eimeria spp. are important factors in determining the intestinal microbial communities. The aim of this study was to verify the prevalence of species and antimicrobial susceptibility of Enterococcus isolated from broilers fed with different supplements and infected experimentally with Eimeria spp. Broilers were divided in eight groups, fed with diets supplemented with a combination of antimicrobial, ionophore-coccidiostatics, probiotic, essential oil. At 14 days old all birds, except the control, received a solution containing oocysts of Eimeria spp. Samples of cloacal swabs from broilers were collected. A total of 240 Enterococcus sp. strains were isolated, confirmed genus by PCR, classified as species, tested for antimicrobial susceptibility and screened by PCR for the presence of tet(L, tet(M and erm(B genes. The overall distribution of species isolated from fecal samples was E. faecalis (40%, followed by E. casseliflavus/E. gallinarum (10.8%, E. mundtii (10.8%, E. faecium (10.8%, E. columbae (5.8% and E. gallinarum (4.2%. Changes in the composition or frequency of Enterococcus species were observed in all dietary supplementation. Antimicrobial susceptibility tests showed resistance phenotypes a range of antibiotics, especially used in humans such as, streptomycin, penicillin, rifampicin and vancomycin. There was no correlation between different supplementation for broilers and antimicrobial resistance and the presence of tet(M, tet(L and erm(B genes. Dietary supplementation had effect on the Enterococcus sp. colonization, but did not have significant effect on the phenotype and genotype of antimicrobial resistance in enterococci.
Morfin-Otero, Rayo; Noriega, Eduardo Rodriguez; Dowzicky, Michael J.
Background The Tigecycline Evaluation and Surveillance Trial (T.E.S.T) is a global antimicrobial surveillance study of both gram-positive and gram-negative organisms. This report presents data on antimicrobial susceptibility among organisms collected in Mexico between 2005 and 2012 as part of T.E.S.T., and compares rates between 2005–2007 and 2008–2012. Method Each center in Mexico submitted at least 200 isolates per collection year; including 65 gram-positive isolates and 135 gram-negative i...
Ogata, Silvio Kazuo; Gales, Ana Cristina; Kawakami, Elisabete
Antimicrobial susceptibility testing for Helicobacter pylori is increasingly important due to resistance to the most used antimicrobials agents. Only agar dilution method is approved by CLSI, but it is difficult to perform routinely. We evaluated the reliability of E-test and disk diffusion comparing to agar dilution method on Helicobacter pylori antimicrobial susceptibility testing. Susceptibility testing was performed for amoxicillin, clarithromycin, furazolidone, metronidazole and tetracycline using E-test, disk-diffusion and agar dilution method in 77 consecutive Helicobacter pylori strains from dyspeptic children and adolescents. Resistance rates were: amoxicillin - 10.4%, 9% and 68.8%; clarithromycin - 19.5%, 20.8%, 36.3%; metronidazole - 40.2%33.7%, 38.9%, respectively by agar dilution, E-test and disk diffusion method. Furazolidone and tetracycline showed no resistance rates. Metronidazole presented strong correlation to E-test (r = 0.7992, p Helicobacter pylori susceptibility testing. Disk diffusion method presented high disagreement and high rates of major errors.
Isoken H. Igbinosa
Full Text Available This study assessed the prevalence of antibiotic-resistant Aeromonas species isolated from Alice and Fort Beaufort wastewater treatment plant in the Eastern Cape Province of South Africa. Antibiotic susceptibility was determined using the disc diffusion method, and polymerase chain reaction (PCR assay was employed for the detection of antibiotics resistance genes. Variable susceptibilities were observed against ciprofloxacin, chloramphenicol, nalidixic acid, gentamicin, minocycline, among others. Aeromonas isolates from both locations were 100% resistant to penicillin, oxacillin, ampicillin, and vancomycin. Higher phenotypic resistance was observed in isolates from Fort Beaufort compared to isolates from Alice. Class A pse1 β-lactamase was detected in 20.8% of the isolates with a lower detection rate of 8.3% for blaTEM gene. Class 1 integron was present in 20.8% of Aeromonas isolates while class 2 integron and TetC gene were not detected in any isolate. The antibiotic resistance phenotypes observed in the isolates and the presence of β-lactamases genes detected in some isolates are of clinical and public health concern as this has consequences for antimicrobial chemotherapy of infections associated with Aeromonas species. This study further supports wastewater as potential reservoirs of antibiotic resistance determinants in the environment.
Full Text Available Abstract Background Antimicrobial resistance of Staphylococcus aureus especially methicillin-resistant S. aureus (MRSA continues to be a problem for clinicians worldwide. However, few data on the antibiotic susceptibility patterns of S. aureus isolates in South Africa have been reported and the prevalence of MRSA in the KwaZulu-Natal (KZN province is unknown. In addition, information on the characterization of S. aureus in this province is unavailable. This study investigated the susceptibility pattern of 227 S. aureus isolates from the KZN province, South Africa. In addition, characterization of methicillin-sensitive S. aureus (MSSA and MRSA are reported in this survey. Methods The in-vitro activities of 20 antibiotics against 227 consecutive non-duplicate S. aureus isolates from clinical samples in KZN province, South Africa were determined by the disk-diffusion technique. Isolates resistant to oxacillin and mupirocin were confirmed by PCR detection of the mecA and mup genes respectively. PCR-RFLP of the coagulase gene was employed in the characterization of MSSA and MRSA. Results All the isolates were susceptible to vancomycin, teicoplanin and fusidic acid, and 26.9% of isolates studied were confirmed as MRSA. More than 80% of MRSA were resistant to at least four classes of antibiotics and isolates grouped in antibiotype 8 appears to be widespread in the province. The MSSA were also susceptible to streptomycin, neomycin and minocycline, while less than 1% was resistant to chloramphenicol, ciprofloxacin, rifampicin and mupirocin. The inducible MLSB phenotype was detected in 10.8% of MSSA and 82% of MRSA respectively, and one MSSA and one MRSA exhibited high-level resistance to mupirocin. There was good correlation between antibiotyping and PCR-RFLP of the coagulase gene in the characterization of MRSA in antibiotypes 1, 5 and 12. Conclusion In view of the high resistance rates of MRSA to gentamicin, erythromycin, clindamycin, rifampicin and
F. Deeba, H. Afzal, M. Siddique and F. M. Khan
Full Text Available A total of 100 fluff samples were collected from five hatcheries located in and around Faisalabad. After isolation of different bacteria in the hatcheries fluff their sensitivity to Norfloxacin, Gentamicin, Flumequine, Chloramphenicol, Neomycin, Ampicillin and Erythromycin was determined. Similarly, the susceptibility of the bacterial isolates for three disinfectants (EWABO ALDEKOL, TH4 and BROMOSEPT and three spray sanitizers (Sani squad. Sanitol and TH4 was also observed. The results indicated that the occurrence of different bacterial species among 148 isolates was: Escherichia coli 62 (41.89%, Paratyphoid salmonellae 24 (16.22%, Salmonella pullorum 3 (2.03%, Proteus mirabelis 2(1.35%, Pseudomonas aeruginosa 4(2.70%, Klebsiella pneumoniae 2(1.35%, Streptococcus faecalis 4 (2.70%, Staphylococcus aureus 22(14.8%, Staphylococcus epidermidis 7 (4.73% and Bacillus subtilis 18 (12.16%. The in vitro sensitivity of the isolates was highest for Norfloxacin (91.89% and the lowest for Erythromycin (16.89 %. The bacterial isolates (Salmonella pullorum, Proteus mirabilis, Klebsiella pneumoniae and Streptococcus faecalis were 100 percent susceptible for all the three disinfectants. Efficacy of sprays Sani Squad and TH4 was 100 percent for some of the bacterial isolates e.g. Salmonella pullorum, Proteus mirabilis and Klebsiella pneumoniae. The efficacy of spray sanitol was more than 60 percent for some of the bacterial isolates including E. coli, Salmonella pullorum and Staphylococcus aureus.
Glupczynski, Y; Delmee, M; Bruck, C; Labbe, M; Avesani, V; Burette, A
Forty-nine isolates of Campylobacter pylori were tested for their susceptibility to twenty antibiotics and four anti-ulcer agents by an agar dilution technique. Penicillin and amoxycillin were the most active drugs (MIC90, 0.06 microgram/ml); erythromycin, cefazolin, minocycline, ciprofloxacin, ofloxacin and gentamicin were slightly less active (MIC90, less than or equal to 1 microgram/ml). Moderate activity was found for doxycyclin, rifampin, nitrofurantoin, norfloxacin, pefloxacin, enoxacin, paromomycin, metronidazole and tinidazole. All strains were resistant to trimethoprim (MIC greater than 512 micrograms/ml). Nalidixic acid (MIC90, greater than 256 micrograms/ml) and colistin (MIC90, greater than 64 micrograms/ml) had little to no activity. Of four anti-ulcer drugs, only bismuth subcitrate showed activity (MIC90, 64 micrograms/ml). Strains resistant to all 4-quinolones were found in patients who had previously received ofloxacin as part of a clinical trial aimed at eradication of C. pylori. These isolates remained susceptible to amoxycillin, tetracyclines and to other classes of antibiotics.
Full Text Available Meningoccocal disease has repeatedly caused outbreaks worldwide. There has been sudden surge of cases of meningococcemia and meningococcal meningitis in early 2005 in Delhi, India and neighboring states of Uttar Pradesh and Haryana. As of June 17, 2005, 429 probable cases of meningococcal disease have been reported in Delhi out of which 128 cases have revealed microbiological evidence of Neisseria meningitidis . It is possible that the number of cases was in excess of the numbers notified. During this episode drug susceptibility testing by MIC method (E-test using break points recently recommended by NCCLS/CLSI, revealed that all isolates were sensitive to penicillin, ampicillin, rifampicin and ceftriaxone. As regards to ciprofloxacin, about two third of the isolates tested were found to be ′non-susceptible′ (MIC =0.03µg/mL- 0.190µg/mL. All the isolates were found resistant to cotrimoxazole (MIC> 16µg/mL. Repeated outbreaks, decreased susceptibility to ciprofloxacin, which is commonly used for chemoprophylaxis of meningococcal disease, highlights the need for a constant surveillance system. Present review deals with various aspects of Neisseria meningitidis and meningococcal disease in view of recent episode.
Full Text Available Sub-clinical mastitis is a main pathology of dairy husbandry because it is not clinically recognized by the owners and the veterinarians. For this reason, its economic loss is usually underestimated in milk production. This study has been undertaken in order to evaluate the epidemiologic situation of sub-clinicalmastitis in Batna and Setif governorates (East of Algeria. For this purpose, a detailed bacteriological study of all bacterial strains isolated from sub-clinical mastitis followed by a study of their antibacterial susceptibility profiles has been undertaken. 89 bacterial strains distributed as follows were studied: 27 strains of staphylococci among which 23 were coagulase-negative staphylococci (CNS that are generally incriminated in sub-clinical mastitis. 39 strains of streptococci among which 10 were Lactococcus lactis ssp lactis strains. 23 strains of enterobacteria represented mainly by Escherichia coli (E.coli. All these bacterial strains were isolated from cow milk of 3 different farms. The antibacterial susceptibility profiles have revealed a susceptibility of the isolated strains to a large number of antibiotics mainly to the Neomycin, the Cephalexin and the Spiramycin. [Vet. World 2011; 4(12.000: 537-541
Valéria Maria Lara
Full Text Available This study evaluated the in vitro antibacterial activity of essential oils from Lippia graveolens (Mexican oregano, Origanum vulgaris (oregano, Thymus vulgaris (thyme, Rosmarinus officinalis (rosemary, Cymbopogon nardus (citronella, Cymbopogon citratus (lemongrass, and Eucalyptus citriodora (eucalyptus against Escherichia coli (n=22 strains isolated from Alouatta spp. feces. Minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC were determined for each isolate using the broth microdilution technique. Essential oils of Mexican oregano (MIC mean = 1818 μg mL−1; MBC mean = 2618 μg mL−1, thyme (MIC mean = 2618 μg mL−1; MBC mean = 2909 μg mL−1, and oregano (MIC mean = 3418 μg mL−1; MBC mean = 4800 μg mL−1 showed the best antibacterial activity, while essential oils of eucalyptus, rosemary, citronella, and lemongrass displayed no antibacterial activity at concentrations greater than or equal to 6400 μg mL−1. Our results confirm the antimicrobial potential of some essential oils, which deserve further research.
Lara, Valéria Maria; Carregaro, Adriano Bonfim; Santurio, Deise Flores; de Sá, Mariangela Facco; Santurio, Janio Moraes; Alves, Sydney Hartz
This study evaluated the in vitro antibacterial activity of essential oils from Lippia graveolens (Mexican oregano), Origanum vulgaris (oregano), Thymus vulgaris (thyme), Rosmarinus officinalis (rosemary), Cymbopogon nardus (citronella), Cymbopogon citratus (lemongrass), and Eucalyptus citriodora (eucalyptus) against Escherichia coli (n = 22) strains isolated from Alouatta spp. feces. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for each isolate using the broth microdilution technique. Essential oils of Mexican oregano (MIC mean = 1818 μg mL(-1); MBC mean = 2618 μg mL(-1)), thyme (MIC mean = 2618 μg mL(-1); MBC mean = 2909 μg mL(-1)), and oregano (MIC mean = 3418 μg mL(-1); MBC mean = 4800 μg mL(-1)) showed the best antibacterial activity, while essential oils of eucalyptus, rosemary, citronella, and lemongrass displayed no antibacterial activity at concentrations greater than or equal to 6400 μg mL(-1). Our results confirm the antimicrobial potential of some essential oils, which deserve further research.
Abdalla, Nazar M; Osman, Amani A; Haimour, Waleed O; Sarhan, Mohammed A A; Mohammed, Mohammed N; Zyad, Eyhab M; Al-Ghtani, Abdalla M
This study aimed at evaluating the sensitivity of antibiotics towards nosocomial infections caused by Acinetobacter species. The study took place during the period Dec. 2011- Dec. 2012 at Assir Central Hospital in collaboration with the department of microbiology, college of medicine, King Khalid University, Abha. A prospective study involving 150 patients presented with nosocomial infections due to Acinetobacter species detected by bacteriological tests; direct microscopy, culture in blood agar media, fermentation test in MacConkey media and MIC (minimum inhibitory concentration) for antibiotics sensitivity using Muller Hinton media and Chemical test using API 20. A 150 nosocomial infections in this study showed gram-negative coccobacilli, non motile, glucose-negative fermentor and oxidase negative. All isolates showed 100% sensitivity to: Imipramine, Meropenem, Colistin. From the rest of tested antibiotics the higher resistant ones were; Nitrofurantoin 87% and Cefoxitin 85%. The least resistant antibiotics; Imipenem 3% and Ticarcillin 7%. While variable resistance in the rest of tested antimicrobials. A 47 patients (31.3%) have used antibiotics prior to this study. The high rate of usage occurred in elder patients. The frequency of Acinetobacter calcoaceticus baumannii complex multi-drugs resistance ABCMDR is rising including almost all commonly used antibiotics. Only few antibiotics exert 100% sensitivity towards these bacteria.
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.
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.
Full Text Available Swab samples obtained from 96 dogs with chronic otitis externa were cultured for the isolation of Staphylococcus species. Of 57 staphylococcal strains, 41 (72% were coagulase-negative (CNS. The identification of staphylococci strains was made by standard procedures for the routine identification of staphylococci in clinical practice. S. sciuri was the most frequent species isolated (22.8% from chronic otitis externa in dogs followed by S. intermedius (12.3%, S. auricularis (10.5% and S. aureus (8.8%. Three (5.2% CNS strains could not be identified. Bacterial isolates were susceptible to enrofloxacin, gentamicin, cephalothin, chloramphenicol and neomycin. Resistance was most common to penicillin G, oxacillin and ampicillin.
YANG Li-ming; WANG Yi-hao; PENG Yu; MIN Jiang-tao; HANG Su-qin; ZHU Wei-yun
To investigate the roles ofEscherichia coli in the pathogenesis of postpartum uterine diseases in dairy cows, a total of 145E. coli isolates were recovered from 18 healthy cows (61 isolates) and 25 cows with clinical endometritis (84 isolates) at 25–35 days after parturition. Genomic characteristics including phylogenetic grouping, genetic diversity and virulence genes of E. coli isolates were screened to proifle the characteristics related to uterine infections. The susceptibility of the bacteria against 23 antibiotics was also evaluated to support prevention and treatment of clinical cases. Genetic diversity ofE. coli identiifed by random ampliifcation of polymorphic DNA (RAPD) revealed 103 clonal types, including 3 common types to unaffected cows and endometritis cows, 39 types speciifc to healthy cows and 61 types in endometritis subjects. In addition, the isolates from endometritis uteri showed more genetic variability compared with that of healthy cows. Ac-cording to the ifndings of phylogenetic grouping, theE. coli isolates were assigned to group A (35.9%), B1 (59.3%) and D (4.8%). The expression of 10 of 20 virulence gens were detected positively, and onlyifmH gene was revealed signiifcantly (P<0.05) associated with endometritis. From antimicrobial susceptibility test,E. coli was found highly resistant to tetracy-cline, ampicilin, carbenicilin and amoxicilin, but sensitive to amikacin, netilmicin, tobramycin, cefepime and ceftazidime. In conclusion,E. coliwere extensively observed in both healthy and endometritis cows, and presented a large clonal types, however, ifmH was the only gene observed associated with clinical endometritis. Our results suggest that the drugs like amikacin, netilmicin, tobramycin and cefepime could be considered for preventing and treating clinical endometritis in the practical management of dairy cow.
Kamelia Mahmoud Osman
Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA have been found in various farm animal species throughout the world. Yet, methicillin-susceptible S. aureus (MSSA, methicillin-susceptible non-S. aureus (MS-NSA and methicillin-resistant non-S. aureus (MR-NSA were not investigated. Therefore, we persued to determine the diversity in theirphenotypic virulence assay, phenotypic antimicrobial resistance profile and molecular characterisation in one of the food chains in Egypt. Samples were collected during 2013 from beef meat at retail. Twenty seven isolates comprising five species (S. hyicus, S. aureus, S. schleiferi subsp. coagulans, S. intermedius and S. lentus were characterized for their antibiotic resistance phenotypic profile and antibiotic resistance genes (mecA, cfr, gyrA, gyrB and grlA. Out of the 27 Staphylococcus isolates only one isolate was resistant to the 12 antibiotics representing nine classes. Raw beef meat sold across the Great Cairo zone, contains 66.7% of MRS, with highest prevalence was reported in S. aureus (66.7%, while the MRS non-S. aureus strains constituted 66.7% from which S. hyicus (60%, S. intermedius (33.3%, S. schleiferi subsp. coagulans (100% and S. lentus (100% were MRS. Seven S. aureus, six S. hyicus, four S. schleiferi subsp. coagulans, three S. intermedius and one S. lentus isolates although being resistant to oxacillin yet, 11/27 (40.7% carried the mecA gene. At the same time, the cfr gene was present in 2 of the nine S. aureus isolates, and totally undetectable in S. hyicus, S. schleiferi subsp. coagulans, S. intermedius and S. lentus. Although global researches largely focused into MRSA and MR-NSA in animals on pigs, the analysis of our results stipulates that buffaloes and cattle could be MRSA dispersers and that this theme is not specific to pigs. Detection of MSSA virulence determinants is a must, as although oxacillin resistance may be absent yet, the MSSA may carry the virulence determinants which could
Osman, Kamelia M; Amer, Aziza M; Badr, Jihan M; Helmy, Nashwa M; Elhelw, Rehab A; Orabi, Ahmed; Bakry, Magdy; Saad, Aalaa S A
Methicillin-resistant Staphylococcus aureus (MRSA) have been found in various farm animal species throughout the world. Yet, methicillin-susceptible S. aureus (MSSA), methicillin-susceptible non-S. aureus (MS-NSA), and methicillin-resistant non-S. aureus (MR-NSA) were not investigated. Therefore, we persued to determine the diversity in their phenotypic virulence assay, phenotypic antimicrobial resistance profile and molecular characterization in one of the food chains in Egypt. Samples were collected during 2013 from beef meat at retail. Twenty seven isolates comprising five species (S. hyicus, S. aureus, S. schleiferi subsp. coagulans, S. intermedius, and S. lentus) were characterized for their antibiotic resistance phenotypic profile and antibiotic resistance genes (mecA, cfr, gyrA, gyrB, and grlA). Out of the 27 Staphylococcus isolates only one isolate was resistant to the 12 antibiotics representing nine classes. Raw beef meat sold across the Great Cairo zone, contains 66.7% of MRS, with highest prevalence was reported in S. aureus (66.7%), while the MRS non-S. aureus strains constituted 66.7% from which S. hyicus (60%), S. intermedius (33.3%), S. schleiferi subsp. coagulans (100%), and S. lentus (100%) were MRS. Seven S. aureus, six S. hyicus, four S. schleiferi subsp. coagulans, three S. intermedius, and one S. lentus isolates although being resistant to oxacillin yet, 11/27 (40.7%) carried the mecA gene. At the same time, the cfr gene was present in 2 of the nine S. aureus isolates, and totally undetectable in S. hyicus, S. schleiferi subsp. coagulans, S. intermedius, and S. lentus. Although, global researches largely focused into MRSA and MR-NSA in animals on pigs, the analysis of our results stipulates, that buffaloes and cattle could be MRSA dispersers and that this theme is not specific to pigs. Detection of MSSA virulence determinants is a must, as although oxacillin resistance may be absent yet, the MSSA may carry the virulence determinants which
Okwori EE; Nwadioha SI; Nwokedi EOP; Odimayo M; Jombo GTA
Objective:To isolate bacterial pathogens and test for their antibiotic susceptibility. Methods:A total of 20 000 samples from 9 different clinical sites were processed in the laboratory between 1987 to 2000. The specimens were inoculated on the appropriate media for the isolation of the bacteria. Biochemical and serology tests were carried out on the organisms to confirm the type of bacteria isolated. Antibiotic susceptibility test was also carried out on each of the bacteria isolated. Results:A total of 18 520 bacteria were isolated from the specimens. The specimens were from nine different clinical sites, i.e. wound accounted for 22.84%, urine 31.67%, blood 12.38%, genital 7.70%, sputum 6.81%, stool 6.28%, cerebrospinal fluid 5.98%, aspirates 3.85%and ear/throat swabs were 2.49%. Gram negative bacteria accounted for 76%of isolates. The main species were Pseudomonas 2 238 (12.08%), Escherichia coli (E. coli) 2 073 (11.19%) and Staphylococcus aureus (S. aureus) which accounted for 2 511 (13.56%) of the total isolates. S. aureus showed 70%and 65%resistance to penicillin and ampicillin, respectively. Surprisingly, 40%of the organism was resistant to cloxacillin. E. coli showed 47%and 42%resistance to ampicillin and gentamicin, respectively. 49%of Salmonella typhi was resistant to chloramphenicol while 37%of Neisseria meningitidis was resistant to penicillin. Conclusions: The rate of bacteria isolated from the clinical specimens is high and antibiotic sensitivity pattern of the organisms vary from one antibiotic to the other.
Maluping, R P; Paul, N C; Moodley, A
Staphylococcus pseudintermedius is a leading aetiologic agent of pyoderma and other body tissue infections in dogs and cats. In recent years, an increased prevalence of methicillin-resistant S. pseudintermedius (MRSP) has been reported. Isolation of MRSP in serious infections poses a major therapeutic challenge as strains are often resistant to all forms of systemic antibiotic used to treat S. pseudintermedius -related infections. This study investigates the occurrence of MRSP from a total of 7183 clinical samples submitted to the authors' laboratories over a 15-month period. Identification was based on standard microbiological identification methods, and by S. pseudintermedius-specific nuc polymerase chain reaction (PCR). Methicillin resistance was confirmed by PBP2a latex agglutination and mecA PCR. Susceptibility against non-beta-lactam antibiotics was carried out using a disc-diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. In addition, susceptibility to pradofloxacin--a new veterinary fluoroquinolone--was also investigated. SCCmec types were determined by multiplex PCR. Staphylococcus pseudintermedius was isolated from 391 (5%) samples and 20 were confirmed as MRSP from cases of pyoderma, otitis, wound infections, urinary tract infection and mastitis in dogs only. All 20 isolates were resistant to clindamycin and sulphamethoxazole/trimethoprim. Nineteen were resistant to chloramphenicol, enrofloxacin, gentamicin, marbofloxacin and pradofloxacin; additionally, seven isolates were resistant to tetracycline. Fifteen isolates carried SCCmec type II-III, four isolates had type V and one harboured type IV. To date, only a few scientific papers on clinical MRSP strains isolated from the UK have been published, thus the results from this study would provide additional baseline data for further investigations.
Carol H Sandt
Full Text Available Salmonellosis is one of the most important foodborne diseases affecting humans. To characterize the relationship between Salmonella causing human infections and their food animal reservoirs, we compared pulsed-field gel electrophoresis (PFGE and antimicrobial susceptibility patterns of non-typhoidal Salmonella isolated from ill humans in Pennsylvania and from food animals before retail. Human clinical isolates were received from 2005 through 2011 during routine public health operations in Pennsylvania. Isolates from cattle, chickens, swine and turkeys were recovered during the same period from federally inspected slaughter and processing facilities in the northeastern United States. We found that subtyping Salmonella isolates by PFGE revealed differences in antimicrobial susceptibility patterns and, for human Salmonella, differences in sources and invasiveness that were not evident from serotyping alone. Sixteen of the 20 most common human Salmonella PFGE patterns were identified in Salmonella recovered from food animals. The most common human Salmonella PFGE pattern, Enteritidis pattern JEGX01.0004 (JEGX01.0003ARS, was associated with more cases of invasive salmonellosis than all other patterns. In food animals, this pattern was almost exclusively (99% found in Salmonella recovered from chickens and was present in poultry meat in every year of the study. Enteritidis pattern JEGX01.0004 (JEGX01.0003ARS was associated with susceptibility to all antimicrobial agents tested in 94.7% of human and 97.2% of food animal Salmonella isolates. In contrast, multidrug resistance (resistance to three or more classes of antimicrobial agents was observed in five PFGE patterns. Typhimurium patterns JPXX01.0003 (JPXX01.0003 ARS and JPXX01.0018 (JPXX01.0002 ARS, considered together, were associated with resistance to five or more classes of antimicrobial agents: ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline (ACSSuT, in 92% of human and
Wisselink, Henk J; Veldman, Kees T; Van den Eede, Chris; Salmon, Sarah A; Mevius, Dik J
The susceptibility of Streptococcus suis strains (n=384) isolated from diseased pigs in seven European countries to 10 antimicrobial agents was determined. For that purpose a microbroth dilution method was used according to CLSI recommendations. The following antimicrobial agents were tested: ceftiofur, cefquinome, enrofloxacin, florfenicol, gentamicin, penicillin, spectinomycin, tetracycline, tilmicosin and trimethoprim/sulphamethoxazole. Using breakpoints established by CLSI for veterinary pathogens, all strains were susceptible to ceftiofur, florfenicol, enrofloxacin and penicillin. MIC-90 values of these antibiotics were MIC-90 values of these antibiotics were 8, 16 and 2 microg/mL, respectively. A high level of resistance was observed for tetracycline (75.1%). A MIC-90 value of 64 microg/mL was found for this antibiotic. Serotype-associated differences in MIC-90 values were observed for tetracycline, tilmicosin and trimethoprim/suphamethoxazole.
Robert P Rennie
Full Text Available In the absence of clinical resistance, breakpoints for many antimicrobial agents are often set high. Clinical failures following use of the agents over time requires re-evaluation of breakpoints. This is based on patient response, pharmacokinetic/pharmacodynamic information and in vitro minimal inhibitory concentration data. Data from the SENTRY Antimicrobial Surveillance Program has shown that Clinical and Laboratory Standards Institute breakpoint changes for carbapenems that occurred between 2008 and 2012 in North America have resulted in decreased levels of susceptibility for some species. In particular, reduced susceptibility to imipenem was observed for Proteus mirabilis (35% and Morganella morganii (80%. Minor decreases in susceptibility were also noted for Enterobacter species with ertapenem (5% and imipenem (4.3%, and Serratia species with imipenem (6.4%. No significant decreases in susceptibility were observed for meropenem following the breakpoint changes. There were no earlier breakpoints established for doripenem. Very few of these Enterobacteriaceae produce carbapenamase enzymes; therefore, the clinical significance of these changes has not yet been clearly determined. In conclusion, ongoing surveillance studies with in vitro minimum inhibitory concentration data are essential in predicting the need for breakpoint changes and in identifying the impact of such changes on the percent susceptibility of different species.
Full Text Available Diabetic patients have higher risk of urinary tract infection (UTI. In the present study, we investigated the impact of glycemic control in diabetic patients on UTI prevalence, type of strains, and their antimicrobial drugs susceptibility. This study was conducted on urine samples from 722 adult diabetic patients from which 252 (35% samples were positive for uropathogens. Most UTI cases occurred in the uncontrolled glycemic group (197 patients versus 55 patients with controlled glycemia. Higher glycemic levels were measured in uncontrolled glycemia group (HbA1c = 8.3 ± 1.5 and 5.4 ± 0.4, resp., P<0.0001. Females showed much higher prevalence of UTI than males in both glycemic groups (88.5% and 11.5%, resp., P<0.0001. In the uncontrolled glycemia group 90.9% of the UTI cases happened at ages above 40 years and a clear correlation was obtained between patient age ranges and number of UTI cases (r=0.94; P=0.017, whereas in the group with controlled glycemia no trend was observed. Escherichia coli was the predominant uropathogen followed by Klebsiella pneumoniae and they were together involved in 76.2% of UTI cases. Those species were similarly present in both diabetic groups and displayed comparable antibiotic resistance pattern. These results highlight the importance of controlling glycemia in diabetic patients to reduce the UTI regardless of age and gender.
Okamoto, Kazuaki; Ikeda, Fumiaki; Kanayama, Shoji; Nakajima, Akiko; Matsumoto, Tatsumi; Ishii, Ritsuko; Umehara, Masatoshi; Gotoh, Naomasa; Hayashi, Naoki; Iyoda, Takako; Matsuzaki, Kaoru; Matsumoto, Satoru; Kawashima, Makoto
Benzoyl peroxide (BPO), a therapeutic agent for acne vulgaris, was assessed for in vitro antimicrobial activity against Propionibacterium acnes using a novel broth microdilution testing that improved BPO solubility. We searched for a suitable culture medium to measure the minimum inhibitory concentration (MIC) of BPO against P. acnes and finally found the Gifu anaerobic medium (GAM) broth supplemented with 0.1(v/v)% glycerol and 2(v/v)% Tween 80, in which BPO dissolved up to 1250 μg/mL and P. acnes grew well. The MICs and minimum bactericidal concentrations (MBCs) of BPO against 44 clinical isolates of P. acnes collected from Japanese patients with acne vulgaris were determined by our testing method using the supplemented GAM broth. The MICs of BPO were 128 or 256 μg/mL against all isolates of P. acnes regardless of susceptibility to nadifloxacin or clindamycin. The MBCs of BPO were also 128 or 256 μg/mL against the same isolates. Moreover, BPO at the MIC showed a rapid bactericidal activity against P. acnes ATCC11827 in time-kill assay. In conclusion, we could develop a novel assay for the MIC and MBC determinations of BPO against P. acnes, which is reliable and reproducible as a broth microdilution testing and the present results suggest that BPO has a potent bactericidal activity against P. acnes.
Jorgensen, James H; Hindler, Janet F
The Clinical and Laboratory Standards Institute (CLSI) recently published a new laboratory guideline for antimicrobial susceptibility testing of infrequently encountered or fastidious bacteria not covered in previous CLSI publications. The organisms include Aeromonas species, Bacillus species, and Vibrio species that may cause infections following environmental exposure. Fastidious organisms that may cause endocarditis or medical device infections include Abiotrophia and Granulicatella species; coryneform bacteria; Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella group gram-negative rods; and the instrinsically vancomycin-resistant gram-positive organisms Erysipelothrix, Lactobacillus, Leuconostoc, and Pediococcus species. Organisms not previously covered in depth in CLSI guidelines include Branhamella catarrhalis, Campylobacter jejuni, Campylobacter coli, Listeria species, and Pasteurella species. Clinically important drug resistance has been reported for each of these organisms. The guidelines provide recommendations for when it may be important to test these organisms, how standard methods may be easily adapted for testing, and appropriate interpretive criteria for results. Communication with infectious diseases clinicians prior to performing such testing is emphasized.
Tejedor Junco, María Teresa; Gonzalez-Martin, Margarita; Rodriguez Gonzalez, Noe Francisco; Gutierrez, Carlos
This study investigated the presence of Enterococcus spp. strains in camel faeces, their virulence factors, and resistance to the antibiotics commonly used as therapy of enterococcal infections. One hundred and seventy three Enterococcus strains were isolated and identified to species level using polymerase chain reaction (PCR). Susceptibility to 11 antimicrobials was determined by disk diffusion method. Minimal Inhibitory Concentrations (MIC) of penicillin, ampicillin, vancomycin, teicoplanin, gentamicin, and streptomycin were all determined. Genes encoding resistance to vancomycin, tetracycline, and erythromycin as well as genes encoding some virulence factors were identified by PCR. Enterococcus hirae (54.3%) and Enterococcus faecium (25.4%) were the species most frequently isolated. None of the strains were resistant to vancomycin, teicoplanin, ampicillin or showed high level aminoglycoside resistance (HLAR). Strains resistant to rifampicin (42.42%) were those most commonly found followed those resistant to trimethoprim - sulfamethoxazole (33.33%). The genes tetM, tetL, vanC1, and vanC2-C3 were detected in some strains. Virulence genes were not detected. Monitoring the presence of resistant strains of faecal enterococci in animal used with recreational purposes is important to prevent transmission of those strains to humans and to detect resistance or virulence genes that could be transferred to other clinically important bacteria.
Berman, Hillary; Barberino, Maria Goreth; Moreira, Edson Duarte; Riley, Lee; Reis, Joice N
The clinical management of meningitis caused by Escherichia coli is greatly complicated when the organism becomes resistant to broad-spectrum antibiotics. We sought to characterize the antimicrobial susceptibilities, sequence types (ST), and presence of known drug resistance genes of E. coli isolates that caused meningitis between 1996 and 2011 in Salvador, Brazil. We then compared these findings to those for E. coli isolates from community-acquired urinary tract infections (UTI) that occurred during the same time period and in the same city. We found that 19% of E. coli isolates from cases of meningitis and less than 1% of isolates from UTI were resistant to third-generation cephalosporins. The sequence types of E. coli isolates from cases of meningitis included ST131, ST69, ST405, and ST62, which were also found among isolates from UTI. Additionally, among the E. coli isolates that were resistant to third-generation cephalosporins, we found genes that encode the extended-spectrum beta-lactamases CTX-M-2, CTX-M-14, and CTX-M-15. These observations demonstrate that compared to E. coli strains isolated from cases of community-acquired UTI, those isolated from cases of meningitis are more resistant to third-generation cephalosporins, even though the same sequence types are shared between the two forms of extraintestinal infections.
Yesilmen, Simten; Vural, Aydin; Erkan, Mehmet Emin; Yildirim, Ibrahim Halil
In this study, the presence of Arcobacter spp. was examined in cow milk (n=50), water buffalo (WB) milk (n=50) and fresh village cheese (n=50) samples. The 16S rDNA-RFLP method was used for the identification of Arcobacter spp. The disc diffusion method was used to investigate the susceptibility of all strains identified to 18 different antimicrobial substances. The most commonly isolated Arcobacter species were found to be Arcobacter butzleri (38.89%), Arcobacter cryaerophilus (22.23%) and Arcobacter skirrowii (11.12%) in cow milk; A. cryaerophilus (33.33%), Arcobacter cibarius (20.83%) and A. butzleri (12.50%) in WB milk; and A. skirrowii (28.57%), A. butzleri (21.43%) and A. cryaerophilus (14.29%) in fresh village cheese. This is the first study to identify the presence of Arcobacter nitrofigilis, Arcobacter cloacae, Arcobacter halophilus, Arcobacter bivalviorum and A. cibarius species in analyzed samples. It was found that all of the A. cryaerophilus (n:16) isolates were resistant to cefoperazone, cloxacillin and penicillin G; all of the A. skirrowii (n:12) and A. butzleri (n:10) isolates were resistant to cefoperazone, tetracycline, ampicillin, erythromycin, cloxacillin and penicillin G. It was concluded that cow milk, WB milk and fresh village cheese samples are an important source of Arcobacter species and pose a risk to public health.
Full Text Available During a 12-year period we isolated five Corynebacterium argentoratense strains identified by phenotypic methods, including the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF and 16S rRNA gene sequencing. In addition, antimicrobial susceptibility was determined, and genome sequencing for the detection of antibiotic resistance genes was performed. The organisms were isolated from blood and throat cultures and could be identified by all methods used. All strains were resistant to cotrimoxazole, and resistance to β-lactams was partly present. Two strains were resistant to erythromycin and clindamycin. The draft genome sequences of theses isolates revealed the presence of the erm(X resistance gene that is embedded in the genetic structure of the transposable element Tn5423. Although rarely reported as a human pathogen, C. argentoratense can be involved in bacteraemia and probably in other infections. Our results also show that horizontal transfer of genes responsible for antibiotic resistance is occurring in this species.
Xie, Wen; Yang, Xin; Wang, Shao-Ii; Wu, Qing-jun; Yang, Ni-na; Li, Ru-mei; Jiao, Xiao-guo; Pan, Hui-peng; Liu, Bai-ming; Feng, Yun-tao; Xu, Bao-yun; Zhou, Xu-guo; Zhang, You-jun
Thiamethoxam has been used as a major insecticide to control the B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Due to its excessive use, a high level of resistance to thiamethoxam has developed worldwide over the past several years. To better understand the molecular mechanisms underlying this resistance in B. tabaci, gene profiles between the thiamethoxam-resistant and thiamethoxam-susceptible strains were investigated using the suppression subtractive hybridization (SSH) library approach. A total of 72 and 52 upand down-regulated genes were obtained from the forward and reverse SSH libraries, respectively. These expressed sequence tags (ESTs) belong to several functional categories based on their gene ontology annotation. Some categories such as cell communication, response to abiotic stimulus, lipid particle, and nuclear envelope were identified only in the forward library of thiamethoxam-resistant strains. In contrast, categories such as behavior, cell proliferation, nutrient reservoir activity, sequence-specific DNA binding transcription factor activity, and signal transducer activity were identified solely in the reverse library. To study the validity of the SSH method, 16 differentially expressed genes from both forward and reverse SSH libraries were selected randomly for further analyses using quantitative realtime PCR (qRT-PCR). The qRT-PCR results were fairly consistent with the SSH results; however, only 50% of the genes showed significantly different expression profiles between the thiamethoxam-resistant and thiamethoxam-susceptible whiteflies. Among these genes, a putative NAD-dependent methanol dehydrogenase was substantially over-expressed in the thiamethoxamresistant adults compared to their susceptible counterparts. The distributed profiles show that it was highly expressed during the egg stage, and was most abundant in the abdomen of adult females.
Full Text Available Background: Wound infection is one of the health problems that is caused and aggravated by the invasion of pathogenic organisms. Information on local pathogens and sensitivity to antimicrobial agent is crucial for successful treatment of wounds. So the present study was conducted to determine antimicrobial susceptibility pattern of bacterial isolates from wound infection and their sensitivity to antimicrobial agents. Methods: A retrospective study was conducted among patients with wound infection in Suyash super speciality hospital, from January 2012 to December 2013. Wound swab was collected using sterile cotton swabs and processed for bacterial isolation and susceptibility testing to Systemic antimicrobial agents. Results: In this study 78 bacterial isolates were recovered from 258 specimens showing an isolation rate of 31.2%. The predominant bacteria isolated from wounds were gram positive staphylococci 36 (46.2%, followed by gram negative streptococci 18 (23.1% gram negative pseudomonas 12 (15.4 % and gram negative proteus 8 (10.4%. The gram positive and gram negative bacteria constituted 68 (87.2% and 10 (12.8% of bacterial isolates; respectively. Conclusion: In the present study most of the pathogens isolated from wound isolates showed high rate of resistance to most commonly used newer antibiotics used to treat bacterial infections. Therefore, rational use of antibiotics should be practiced. [Int J Res Med Sci 2015; 3(2.000: 433-439
In vitro antimicrobial susceptibility of Mycoplasma mycoides mycoides large colony and Arcanobacterium pyogenes isolated from clinical cases of ulcerative balanitis and vulvitis in Dorper sheep in South Africa
A. Kidanemariam; Gouws, J.; M. van Vuuren; Gummow, B.
The in vitro activities of enrofloxacin, florfenicol, oxytetracycline and spiramycin were determined against field isolates of Mycoplasma mycoides mycoides large colony (MmmLC) by means of the broth microdilution technique. The minimum inhibitory concentrations (MICs) of these antimicrobial drugs were determined for a representative number of 10 isolates and 1 type strain. The susceptibility of Arcanobacterium pyogenes to enrofloxacin, oxytetracycline and tilmicosin was determined by means of...
Farrokhzad, F.; Barari, Amin; Choobbasti, A. J.
The purpose of this study was to create an empirical model for assessing the landslide risk potential at Savadkouh Azad University, which is located in the rural surroundings of Savadkouh, about 5 km from the city of Pol-Sefid in northern Iran. The soil longitudinal profile of the city of Babol......, located 25 km from the Caspian Sea, also was predicted with an artificial neural network (ANN). A multilayer perceptron neural network model was applied to the landslide area and was used to analyze specific elements in the study area that contributed to previous landsliding events. The ANN models were...... studies in landslide susceptibility zonation....
Verroken, Alexia; Defourny, Lydwine; le Polain de Waroux, Olivier; Belkhir, Leïla; Laterre, Pierre-François; Delmée, Michel; Glupczynski, Youri
Shortening the turn-around time (TAT) of positive blood culture (BC) identification (ID) and susceptibility results is essential to optimize antimicrobial treatment in patients with sepsis. We aimed to evaluate the impact on antimicrobial prescription of a modified workflow of positive BCs providing ID and partial susceptibility results for Enterobacteriaceae (EB), Pseudomonas aeruginosa and Staphylococcus aureus on the day of BC positivity detection. This study was divided into a pre-intervention period (P0) with a standard BC workflow followed by 2 intervention periods (P1, P2) with an identical modified workflow. ID was performed with MALDI-TOF MS from blood, on early or on overnight subcultures. According to ID results, rapid phenotypic assays were realized to detect third generation cephalosporin resistant EB/P. aeruginosa or methicillin resistant S. aureus. Results were transmitted to the antimicrobial stewardship team for patient's treatment revision. Times to ID, to susceptibility results and to optimal antimicrobial treatment (OAT) were compared across the three study periods. Overall, 134, 112 and 154 positive BC episodes in P0, P1 and P2 respectively were included in the analysis. Mean time to ID (28.3 hours in P0) was reduced by 65.3% in P1 (10.2 hours) and 61.8% in P2 (10.8 hours). Mean time to complete susceptibility results was reduced by 27.5% in P1 and 27% in P2, with results obtained after 32.4 and 32.6 hours compared to 44.7 hours in P0. Rapid tests allowed partial susceptibility results to be obtained after a mean time of 11.8 hours in P1 and 11.7 hours in P2. Mean time to OAT was decreased to 21.6 hours in P1 and to 17.9 hours in P2 compared to 36.1 hours in P0. Reducing TAT of positive BC with MALDI-TOF MS ID and rapid susceptibility testing accelerated prescription of targeted antimicrobial treatment thereby potentially improving the patients' clinical outcome.
Rebecca A. Keel
Full Text Available The objective of this study was to assess the profile of a variety of dosing regimens for common intravenous antibiotics against contemporary Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa isolates collected in Canada during 2009, using pharmacodynamic modelling techniques. Monte Carlo simulation was conducted for standard and/or prolonged infusion regimens of cefepime, ceftazidime, ceftriaxone, ciprofloxacin, doripenem, ertapenem, meropenem and piperacillin/tazobactam. The cumulative fraction of response (CFR was calculated using bactericidal targets for each regimen against each species. All cefepime, doripenem, ertapenem and meropenem regimens achieved optimal exposures against Enterobacteriaceae, whereas target attainment was organism and dose dependent for the other agents. These results support that the currently recommended antimicrobial dosing regimens generally attain acceptable exposures to achieve the requisite pharmacodynamic targets against the Enterobacteriaceae species; however, they fall short of obtaining optimal bactericidal exposures against P aeruginosa.
Basavaraj C Metri
Full Text Available Background: Recently, the isolation of this pathogen in hospital settings is increasing and multidrug-resistant strains are emerging; these strains present a challenge for clinician and the clinical microbiologist because of their increased occurrence in nosocomial infection. The current study was done to find out the antibiotic sensitivity pattern of Citrobacter species from various clinical specimens. Materials and Methods: Samples were collected from patients in accordance with standard protocols. Citrobacter species were identified by conventional biochemical tests. Antibiotic susceptibility of the isolates was done by disc diffusion method according to National Committee for Clinical Laboratory Standards (NCCLS recommendations. Results: Out of 563 isolates of Citrobacter, majority were from pus (48.1%, followed by urine (24.3%, sputum (20.3%, body fluids (05.2%, blood (02.1%. C. koseri was the predominant species [391 (70%] isolated. Infection was nosocomialy acquired in 493 (87.4% patients. The mean age was 39.5 years. Anti-biograms of Citrobacter isolates revealed that effective agent against Citrobacter isolates was imipenem (91.8% sensitive, followed by piperacillin/tazobactam (58.3% and amikacin (53.4%. Conclusion: Citrobacter isolates resistant to multiple anti-microbial agents have emerged, including strains resistant to imipenem, making it an emerging nosocomial pathogen. Therefore, the results of this study suggest that surveillance of anti-microbial resistance in Citrobacter is necessary. Antibiotic policy should be formulated in the hospital. Depending on the antibiotic sensitivity pattern of the Citrobacter isolates, antibiotics should be used, and proper infection control measures should be strictly followed to prevent spread of this pathogen.
Hao, Dan; Xing, Xiaonan; Li, Guanghui; Wang, Xin; Zhang, Min; Zhang, Weisong; Xia, Xiaodong; Meng, Jianghong
The aim of this study was to investigate the prevalence of Staphylococcus aureus in quick-frozen dumplings and to characterize these strains. A total of 120 dumpling samples, including lamb (n = 13), vegetarian (n = 14), seafood (n = 12), and pork (n = 81) stuffing, were collected in Shaanxi province in China and screened for S. aureus. All S. aureus isolates were characterized by antimicrobial susceptibility testing, and detection of genes encoding staphylococcal enterotoxins, exfoliative toxins A and B (eta and etb), toxic shock syndrome toxin 1 (tsst-1), and resistance to methicillin-oxacillin (mecA). In all, 60.0% of all samples were positive for S. aureus, and 117 S. aureus isolates, including seven mecA-positive strains, were recovered from these positive samples. In addition, all mecA-positive S. aureus isolates were recovered from products of animal origin. In these S. aureus isolates, resistance was observed most frequently to ampicillin (92.3%) and penicillin (86.3%), followed by clarithromycin, erythromycin, midecamycin, tetracycline, and kanahemycin (from 53.8 to 28.2%). All isolates were sensitive to cefoperazone, minocycline, vancomycin, and ofloxacin. The predominant toxin gene was sec (38.5%), followed by seg (19.7%), sej (16.2%), see (12.8%), sea (11.1%), and seb (10.3%), whereas eta, etb, and tsst-1 genes were not detected. These findings indicate that S. aureus was present commonly in quick-frozen dumplings, accompanied by multiple antimicrobial resistance and toxin genes. Our findings highlight the urgency for stricter hygiene strategies in food production and the prudent use of antibiotics in the breeding industry.
Robert D. Wojtyczka
Full Text Available The hospital environment microflora comprise a wide variety of microorganisms which are more or less pathogenic and where staphylococci are one of the most common types. The aim of the presented study was to evaluate the prevalence of the biofilm forming coagulase-negative staphylococci (CoNS in a hospital environment as a risk factor for nosocomial infections. Among 122 isolated and tested strains of CoNS the most frequent were: S. epidermidis—32 strains, S. haemolyticus—31 strains, S. capitis subsp. capitis— 21 strains, S. hominis—11 strains, S. cohnii subsp. cohnii—nine strains. In case of CoNS, the main molecule responsible for intercellular adhesion is a polysaccharide intercellular adhesin (PIA, encoded on the ica gene operon. The analysis revealed the presence of the icaADBC operon genes in 46.88% of S. epidermidis isolates. IcaA and icaD were present in 34.38% and 28.13% of strains respectively while IcaC gene was present in 37.50% of strains. IcaB gene was found in 21.88% of S. epidermidis strains. In 15 (63% strains all icaADBC operon genes were observed. The assessment of antibacterial drugs susceptibility demonstrated that analyzed CoNS strains were highly resistant to macrolides and lincosamides and more sensitive to rifampicin and linezolid. Our data indicates that the hospital environment can be colonized by biofilm forming coagulase-negative staphylococci and transmission of these strains can cause an increased risk of serious nosocomial infections.
Full Text Available Staphylococcus aureus colonization and infection occur more commonly among persons living or working in crowded conditions, but characterization of S. aureus colonization within medical communities in China is lacking. A total of 144 (15.4%, 144/935 S. aureus isolates, including 28 (3.0%, 28/935 MRSA isolates, were recovered from the nares of 935 healthy human volunteers residing on a Chinese medical college campus. All S. aureus isolates were susceptible to vancomycin, quinupristin/dalfopristin and linezolid but the majority were resistant to penicillin (96.5%, ampicillin/sulbactam (83.3% and trimethoprim/sulfamethoxazole (93.1%. 82%, (23/28 of the MRSA isolates and 66% (77/116 of the MSSA isolates were resistant to multiple antibiotics, and 3 MRSA isolates were resistant to mupirocin--an agent commonly used for nasal decolonization. 16 different sequence types (STs, as well as SCCmec genes II, III, IVd, and V, were represented among MRSA isolates. We also identified, for the first time, two novel STs (ST1778 and ST1779 and 5 novel spa types for MRSA. MRSA isolates were distributed in different sporadic clones, and ST59-MRSA-VId- t437 was found within 3 MRSA isolates. Moreover, one isolate with multidrug resistance belonging to ST398-MRSA-V- t571 associated with animal infections was identified, and 3 isolates distributed in three different clones harbored PVL genes. Collectively, these data indicate a high prevalence of nasal MRSA carriage and molecular heterogeneity of S. aureus isolates among persons residing on a Chinese medical college campus. Identification of epidemic MRSA clones associated with community infection supports the need for more effective infection control measures to reduce nasal carriage and prevent dissemination of MRSA to hospitalized patients and health care workers in this community.
Manfreda, Gerardo; Parisi, Antonio; De Cesare, Alessandra; Mion, Domenico; Piva, Silvia; Zanoni, Renato G
In this retrospective study, typing ability, discriminatory power, and concordance between typing results obtained on 123 Campylobacter jejuni turkey isolates, collected in 1998, within 14 different farms, applying multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), antibiotic resistance profile, and virulence gene pattern, were assessed and compared. Overall, 33 sequence types, 28 pulsotypes, 10 resistotypes, and 5 pathotypes were identified. MLST and PFGE showed the better discriminatory ability (i.e., Simpson's diversity index >0.90) as well as unidirectional (i.e., Wallace and adjusted Wallace coefficients >0.86) and bidirectional (i.e., adjusted Rand coefficient >0.60) concordance. Moreover, both methods showed a good unidirectional and bidirectional concordance with the resistotype. On the contrary, the congruence of both genotyping methods and resistotype with the pathotype seemed due to chance alone. A clonal relationship was identified among 66.7% of the isolates. Furthermore, 59.7% of the investigated isolates were resistant to two or more antimicrobials and 92% to tetracycline. All the isolates harbored cadF and pldA genes, whereas a flaA gene product and a cdtB gene product were amplified from 85.4% and 79.7% of the isolates, respectively, using the primers designed by Bang et al. (2003). The results of this study clarify the level of genetic diversity among the C. jejuni originating from turkeys. MLST level of correlation with PFGE, resistotype, and pathotype is assessed. This result supports the selection of type and number of typing methods to use in epidemiological studies. Finally, the identification of clonal complexes (i.e., groups of profiles differing by no more than one gene from at least one other profile of the group using the entire Campylobacter MLST database) shared between turkey and human isolates suggests that turkeys could be a possible source of Campylobacter infection.
Full Text Available Context: Gonorrhoea is one of the most common sexually transmitted infections (STI in developing countries and is a global health problem. Aims: To analyze the trend of antimicrobial susceptibility of Neisseria gonorrhoeae isolates over the years, in a tertiary care hospital of North India. Settings and Design: The study population comprised males with urethritis and females with endocervicitis attending STI clinic of our hospital. Materials and Methods: In our STI laboratory, all gonococcal isolates are subjected to antimicrobial susceptibility testing by disc diffusion method as per CLSI guidelines. β-lactamase production is determined by chromogenic cephalosporin test. Minimum Inhibitory Concentration (MIC for ceftriaxone is determined by E-test. Statistical Analysis Used: Data were expressed as percentages. The differences in percentages were tested for statistical significance by using χ2 test and P values were determined. Results: The percentage of penicillinase producing N. gonorrhoeae (PPNG increased from 8% in 1995-96 to 20% in 2004-05 and 88% in 2011-2013. Quinolone-resistant N. gonorrhoeae (QRNG showed a significant increase from 12% in 1995-96 to 98.3% in 2004-05, while 84% isolates were found to be QRNG by 2011-2013. In January 2013 we detected our first gonococcal isolate with decreased susceptibility to third-generation cephalosporins; Ceftriaxone, Cefixime and Cefpodoxime (MIC for ceftriaxone = 0.19 μg/ml. Conclusions: The results of our study highlighted an alarming increase in the percentage of PPNG and QRNG strains over the years. Emergence of N. gonorrhoeae isolates with decreased susceptibility to third-generation cephalosporins is a cause of concern and thus emphasises the importance of antimicrobial susceptibility testing.
Full Text Available From March 1999 to March 2000, we conducted a prospective multicenter study of candidemia involving five tertiary care hospitals from four countries in Latin America. Yeast isolates were identified by classical methods and the antifungal susceptibility profile was determined according to the National Committee for Clinical Laboratory Standards microbroth assay method. During a 12 month-period we were able to collect a total of 103 bloodstream isolates of Candida spp. C. albicans was the most frequently isolated species accounting for 42% of all isolates. Non-albicans Candida species strains accounted for 58% of all episodes of candidemia and were mostly represented by C. tropicalis (24.2% and C. parapsilosis (21.3%. It is noteworthy that we were able to identify two cases of C. lusitaniae from different institutions. In our casuistic, non-albicans Candida species isolates related to candidemic episodes were susceptible to fluconazole. Continuously surveillance programs are needed in order to identify possible changes in the species distribution and antifungal susceptibility patterns of yeasts that may occurs after increasing the use of azoles in Latin American hospitals.
Schweitzer, Nóra; Dán, Ádám; Kaszanyitzky, Éva; Samu, Péterné; Tóth, Ádám György; Varga, János; Damjanova, Ivelina
Campylobacter spp. are the most common cause of bacterial enteritis in Hungary, and the aim of this study was to identify the distribution, genotypes, and antimicrobial susceptibility of Campylobacter species in the most important food-producing animals at the time of slaughter during 2008 and 2009. Of 1,110 samples, 266 were identified as Campylobacter coli (23.9%) and 143 as C. jejuni (12.9%) by real-time PC