Prevalence and characteristics of fecal antimicrobial-resistant Escherichia coli in a cohort of Japanese men undergoing prostate biopsy.

Objectives: To examine resistant Escherichia coli in rectal swab culture of Japanese men undergoing prostate biopsy, and to determine its prevalence, genotypic characteristics and carriage risk factors.

Methods: Rectal swabs of consecutive men undergoing transrectal ultrasound-guided prostate biopsy from April 2013 to March 2015 were cultured to isolate fluoroquinolone-resistant and extended-spectrum β-lactamase-producing E. coli. The prevalence and antimicrobial susceptibility of these resistant E. coli strains and extended-spectrum β-lactamase genotyping were examined. The risk factors of antimicrobial resistance carriage were also examined.

Results: The cohort was 376 men with a mean age of 67.8 years. Fluoroquinolone-resistant E. coli and extended-spectrum β-lactamase-producing E. coli were detected in 37 men (9.8%) and 22 men (5.9%), respectively, with fluoroquinolone-resistant and/or extended-spectrum β-lactamase-producing E. coli in 48 men (13.0%). All 49 antimicrobial-resistant strains were susceptible to tazobactam/piperacillin, amikacin, fosfomycin, meropenem and faropenem. CTX-M-9 and CTX-M-1 group were detected in 14 (63.6%) and eight (36.4%) men, respectively. CTX-M-9 showed relatively higher susceptibility to LVFX and minocycline compared with CTX-M-1. Diabetes mellitus was a significant factor for carriage of resistance by multivariate analysis (odds ratio 2.12, P = 0.039).

Conclusions: The present study showed the fecal carriage of fluoroquinolone-resistant E. coli and extended-spectrum β-lactamase-producing E. coli at 9.8% and 5.9%, respectively, with CTX-M-9 group of extended-spectrum β-lactamase-producing E. coli comprising 63.6%, in Japanese men receiving prostate biopsy. The carriage of fluoroquinolone-resistant and/or extended-spectrum β-lactamase-producing E. coli was significantly related to diabetes.