Distribution of ciprofloxacin-resistance genes among ST131 and non-ST131 clones of Escherichia coli isolates with ESBL phenotypes isolated from women with urinary tract infection.

BACKGROUND AND

OBJECTIVES

Escherichia coli (E. coli) sequence type 131 (ST131) is associated with extended-spectrum beta-lactamase (ESBL) production and fluoroquinolone resistance. This study aimed to investigate the prevalence of ST131, ESBL, and plasmid-mediated quinolone resistance (PMQR) genes in the ciprofloxacin-resistant (CIPR) and ESBL producers from women with UTI.

MATERIALS AND

METHODS

The CIP-resistant ESBL producing (CIPR/ESBL+) E. coli isolates were screened for ST131-by specific PCR of mdh and gyrB. The ESBL and PMQR genes were screened by single PCR. The ST131 and non-ST131 isolates were selected to determine the mutations of gyrA and parC using PCR and sequencing, and also their genetic background by the Pasteur-MLST scheme.

RESULTS

Overall, 55% (33/60) CIPR/ESBL+ isolates were identified as ST131 (94% O25b-ST131). Resistance rate to ampicillin-sulbactam (70%), aztreonam (97%) and gentamicin (61%), the prevalence of aac(6')-Ib-cr (66%), bla CTX-M-15 (82%), the profile of qnrS+aac(6')-Ib-cr (30%), and the double mutation in the parC was significantly higher in ST131 than non- ST131 isolates. The coexistence of PMQR and ESBL genes was found in more than 50% of ST131 and non-ST131 isolates. ST131 isolates differentiated into PST43 and PST506.

CONCLUSION

Management of women with UTI caused by the CIPR/ESBL+ isolates (ST131) co-harbored PMQR, ESBL, and chromosomal mutations, is important for their effective therapy.