Hidden Danger: Superbug Escherichia coli Isolated from Urine Isolates of Outpatient Women with Uncomplicated Urinary Tract Infection

Abstract

BACKGROUND/AIMS Escherichia coli (E. coli) is responsible for the vast majority of uncomplicated bacterial urinary tract infection (UTI) cases in women. The high ability of the isolates to develop antimicrobial resistance makes the treatment difficult. In this study, we investigated the presence of plasmid-mediated quinolone resistance (PMQR) genes in E. coli isolates and their relationship with extended-spectrum beta-lactamases (ESBL). MATERIAL and METHODS A total of 300 E. coli isolates from urine specimens of women, including 108 ESBL producers and 192 non-ESBL producers, were analyzed. The ESBL production was examined using the E-test ESBL strips, and the carbapenemase activity was examined using the CarbaNP test. The presence of PMQR genes (qnrA, qnrB, qnrS, and aac (6´)-Ib) among urine isolates was investigated using polymerase chain reaction. Conjugation experiments were performed to detect the horizontal transferability of the PMQR-positive plasmid. RESULTS Among the ESBL-EC isolates, ciprofloxacin resistance was determined at 69%. Eight isolates were resistant to carbapenems. The aac(6’)-Ib-cr variant was found in 40% of ciprofloxacin-resistant E. coli isolates. None of the isolates harbored the qnrA, qnrB, or qnrS gene. The transferability was 14% for aac(6’)-Ib-cr. The MICs of transconjugants showed increased resistance to fluoroquinolones compared with the recipient E. coli J53AzR. CONCLUSION: This study showed that the frequency of PMQR genes in ESBL-producing superbug E. coli isolates reduced therapeutic options for treating community-acquired UTIs in affected women and that a careful use of antibiotics is very important.