Frequency of quinolone resistance genes among extended-spectrum β-lactamase (ESBL)-producing strains isolated from urinary tract infections.

BACKGROUND

As an opportunistic pathogen, () is widely recognized as the main cause of nosocomial infections as well as some disorders especially those associated with urinary tract infections (UTIs). This study, therefore, sets out to determine the extent of antibiotic resistance to quinolones and to measure the frequency of genes (A, B, and S) within extended-spectrum beta-lactamase (ESBL) and non-ESBL-producing strains of isolated from UTI-diagnosed patients as well as to investigate their antimicrobial susceptibility patterns for some selected antibiotics in southwest Iran.

METHODS

Two hundred strains were isolated from UTI-diagnosed patients, hospitalized in nine different wards of Ahvaz Golestan Hospital between November 2015 and March 2016. The isolates were confirmed through well-practiced phenotypical methods. Moreover, the antimicrobial susceptibility test was successfully performed using a disk diffusion method. ESBL production among the isolates was screened by double disk synergism test (DDST), and the genes were identified using a multiplex PCR.

RESULTS

Out of the 200 samples collected, 167 isolates were confirmed to be strains. Maximum and minimum resistance were reported against nalidixic acid and chloramphenicol with 65.3% and 17.4%, respectively. Most of the isolates were resistant to all three types of quinolones studied in this research. Using multiplex PCR, the genes were found in 100 (59.88%) strains (A = 10, B = 21, S = 41, B-S = 21, B-A = 1, A-S = 3, A-B-S = 3), 58% of which was found among ESBL-producing isolates.

CONCLUSIONS

Resistance to quinolones antibiotics was highest among ESBL-producing isolates harboring, especially S among other determinants of the gene. There is a need for sensitive antibiotic stewardship especially in hospitals of Ahvaz, Khuzestan province. Further research is needed to ascertain the gravity of quinolones resistance in Iran and to quickly act against its spread among other nosocomial pathogens.