High prevalence of ß-lactam and fluoroquinolone resistance in various phylotypes of Escherichia coli isolates from urinary tract infections in Jiroft city, Iran.

BACKGROUND: Urinary tract infection (UTI) is one of the most prevalent infectious diseases with worldwide health threatening. Antimicrobial resistant strains of Escherichia coli (E. coli) are a common cause of UTI which were identified as a treatment challenge. This study aimed to assay the prevalence of common ß-lactam resistance genes including blaTEM, blaSHV, blaCTX-M and blaCMY and phenotypic resistance to commonly used ß-lactam and fluoroquinolone antibiotics in UTIs. These factors were evaluated in various phylogenetic groups (phylotypes) of E. coli isolates. Real-time PCR was applied to detect ß-lactam resistance genes and conventional PCR was used to determine the phylotypes. Phenotypic resistance against ß-lactams (ceftazidime, cefotaxime, aztreonam and ceftriaxone) and fluoroquinolones (ciprofloxacin) were identified by the disc diffusion technique. The ability of extended spectrum ß-lactamases (ESBLs) production in E. coli isolates was detected using the combined disc diffusion method. RESULTS: The prevalence of resistance genes were 89.6% for blaTEM, 44.3% for blaCTX-M, 6.6% for blaSHV and 0.9% for blaCMY. The two high prevalent phylotypes were B2 (29.2%) and D (17.9%) followed by E (14.1%), F (9.4%), C (6.6%) and 10.3% of isolates were unknown in phylotyping. Disc diffusion results showed high prevalence of antibiotic resistance to cefotaxime (88.6%), aztreonam (83%), ceftireaxon (77.3%), ceftazidime (76.4%) and ciprofloxacin (55.6%). Totally, 52.8% of isolates were found as phenotypical ESBL-producers. CONCLUSIONS: This study's results confirmed an explosion of antibiotic resistance amongst E. coli isolates from UTI against ß-lactams and fluoroquinolones. Findings explain the necessity of deep changes in quantity and quality of drug resistance diagnosis and antibiotic therapy strategies. More studies are suggested to better and confident evaluations.

Molecular characterization and antimicrobial resistance of potentially human-pathogenic Escherichia coli strains isolated from riding horses.

BACKGROUND: Transmission of antimicrobial resistant and virulent Escherichia coli (E. coli) from animal to human has been considered as a public health concern. This study aimed to determine the phylogenetic background and prevalence of diarrheagenic E. coli and antimicrobial resistance in healthy riding-horses in Iran. In this research, the genes related to six main pathotypes of E. coli were screened. Also, genotypic and phenotypic antimicrobial resistance against commonly used antibiotics were studied, then phylo-grouping was performed on all the isolates. RESULTS: Out of 65 analyzed isolates, 29.23 % (n = 19) were determined as STEC and 6.15 % (n = 4) as potential EPEC. The most prevalent antimicrobial resistance phenotypes were against amoxicillin/clavulanic acid (46.2 %) and ceftriaxone (38.5 %). blaTEM was the most detected resistance gene (98.4 %) among the isolates and 26.15 % of the E. coli isolates were determined as multi-drug resistant (MDR). Three phylo-types including B1 (76.92 %), A (13.85 %) and D (3.08 %) were detected among the isolates. CONCLUSIONS: Due to the close interaction of horses and humans, these findings would place emphasis on the pathogenic and zoonotic potential of the equine strains and may help to design antimicrobial resistance stewardship programs to control the dissemination of virulent and multi-drug resistant E. coli strains in the community.