Prevalence of integrons and a new dfrA17 variant in Gram-negative bacilli which cause community-acquired infections

PubMed: 20236427A hundred and eleven Gram-negative bacilli from community-acquired infections were characterized by antimicrobial susceptibility testing, screened for class 1 and 2 integrons, and statistically evaluated for the association between antibiotic profile and the presence of integrons. The frequency with which integrons were harbored was 28.8%. Three E. coli strains contained a dfrA17 variant inserted in a class 1 integron. Results of PFGE indicated that some E. coli strains carrying integrons were clonally related. Carriage of gene cassettes was significantly associated with resistance to certain antibiotics (P < 0.05). © 2010 The Societies and Blackwell Publishing Asia Pty Ltd

Molecular analysis of antimicrobial resistance in Yersinia ruckeri strains isolated from rainbow trout (Oncorhynchus mykiss) grown in commercial fish farms in Turkey

In this study, molecular characterization of antimicrobial resistance of 116 Yersinia ruckeri strains isolated from rainbow trout (Oncorhynchus mykiss) with enteric redmouth disease (ERM) in commercial fish farms in the Northern and Eastern regions of Turkey was performed. The putative Y ruckeri strains isolated were confirmed by PCR assays specific to the 16S rRNA gene of bacterium Y. ruckeri. Eighty-six (74.1%) strains were identified to belong to serovar O1 by agglutination test in which type O1 antibody was used. No strains carried antimicrobial gene cassettes inserted into intégrons. Neither TEM- nor SHV-type ß-lactamase gene was found in ampicillin-resistant strains (33/116). tetA and tetB genes were screened in 41/116 oxytetracycline-resistant strains by PCR, and it was found that 21 (51.2%) carried a tetA and/or tetB gene. We conclude that the antimicrobial resistant Y ruckeri strains may act as a reservoir of antimicrobial resistance genes within fish farm environments

Molecular characterization of antibiotic resistant Escherichia coli strains isolated from tap and spring waters in a coastal region in Turkey

PubMed: 17978796A hundred and seventeen antibiotic-resistant Escherichia coli strains were isolated from public tap and spring waters which were polluted by fecal coliforms. There were no significant differences between two water sources as to the coliform pollution level (p> 0.05). All E. coli isolates were detected to be resistant to one or more antibiotics tested. Nearly 42% of the isolates showed multiresistant phenotype. Three (2.5%) of these isolates contained class 1 integron. Sequencing analysis of variable regions of the class 1 integrons showed two gene cassette arrays, dfr1-aadA1 and dhfrA17-aadA5. Resistance to ampicillin, tetracycline or trimethoprim-sulfamethoxazole was transferable according to the results of conjugation experiments. The rate of tetracycline resistance was 15%. tei(A)-mediated tetracycline resistance was widespread among tetracycline-resistant E. coli isolates. Genotyping by BOX-polymerase chain reaction (BOX-PCR) showed that some of the strains were epidemiologically related. This is the first report on the prevalence and characterization of class 1 integron-containing E. coli isolates of environmental origin in Turkey. Copyright © 2007, The Microbiological Society of Korea

Molecular epidemiology of clinical Pseudomonas aeruginosa isolates carrying IMP-1 metallo-?-lactamase gene in a university hospital in Turkey

PubMed: 17949306Pseudomonas aeruginosa isolates carrying IMP- or VIM-type metallo-?-lactamase (MBL) have been increasingly reported in hospitals worldwide. One hundred P. aeruginosa clinical isolates from unrelated inpatients hospitalized at a Turkish university hospital were screened for the presence of blaIMP and blaVIM genes by polymerase chain reaction (PCR). One (1%) isolate was found to carry a VIM-type MBL gene, whereas nine (9%) carried an IMP-1 MBL gene carried on a cassette inserted into a class 1 integron. Only four of the IMP producers were detected as MBL producers according to E-test MBL. Minimum inhibitory concentrations (MICs) of imipenem for the IMP-1 and VIM-type MBL-producers were highly variable (MIC values, 8-128 ?g/ml). Imipenem resistance was not plasmid-mediated according to the transformation assays. Piperacillin/tazobactam was the only effective drug in antimicrobial susceptibility testing. No aztreonam-resistant IMP and VIM producers were detected to produce an extended-spectrum ?-lactamase (ESBL). Three class 1 integrons of approximately 2,300 bp, 1,800 bp, and 1,500 bp in size were detected in each of the nine IMP-positive isolates. Sequencing revealed three novel gene cassette arrays, aac(3)-1c-cmlA5, bla IMP-1-aadA7-like, and aacA7-smr-2-orfD. Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) indicated that a clonal spread of IMP-1-producers had occurred in this hospital. © 2007 Mary Ann Liebert, Inc

Investigation of antibiotic resistance profile and TEM-type ?-lactamase gene carriage of ampicillin-resistant Escherichia coli strains isolated from drinking water

Fifty-five ampicillin-resistant (Ampr) Escherichia coli strains were isolated from 51 drinking water points in Rize region containing abundant fresh water sources in Turkey during the years 2000 to 2002 and from January to February 2004. The large number of organisms (nearly 57%) exhibited resistance to three or more antibiotics commonly used in human and veterinary medicine. These strains displayed a multiresistant phenotype. Nearly half of the strains (27%) expressed resistance to ceftazidime, but these strains were not an extended-spectrum ?-lactamase-producer according to the results of double-disk synergy test. All isolates were then screened for the carriage of TEM-type ?-lactamase gene (blaTEM) by polymerase chain reaction. TEM-type ?-lactamase genes were found in six (11%) isolates. Sequence analysis showed TEM-1 type genes. However, isoelectric focusing analysis did not confirm the production of TEM-1 type ?-lactamase except for one strain. Conjugation experiments showed that resistance to ampicillin, tetracycline or trimethoprim/sulfamethoxazole was transferable in six (11%) isolates. Emergence of transferable antibiotic resistance and blaTEM-1 gene in E. coli strains from public drinking waters possesses a significant public health risk