Urinary tract infections (UTIs) are common in women, and during pregnancy can cause significant morbidity. Growing and greatly varying antimicrobial resistance (AMR) of Enterobacteriaceae, responsible for most UTIs, necessitates regular local AMR surveillance. In obstetric population, where beta-lactams are the mainstay for treatment of severe UTIs, particular focus should be placed on beta-lactam resistance. This study aimed to evaluate AMR rates and frequency of extended spectrum beta-lactamase (ESBL) and carbapenemase genes in uropathogenic Enterobacteriaceae among reproductive-age women in St. Petersburg, Russia.

Urine samples were collected from consecutive reproductive-age women, who attended the D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology from October 2017 to November 2019, and cultured according to routine procedures. Susceptibility to antibiotics and ESBL production was determined using the disc diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. All urine samples and Enterobacteriaceae isolates were tested for ESBL and carbapenemase genes using real-time PCR.

Enterobacteriaceae were detected in 91 (56 pregnant and 35 non-pregnant) of 119 (76%) included women. The vast majority of Enterobacteriaceae strains were susceptible to nitrofurantoin, fosfomycin and meropenem (99–100%). The frequency of strains susceptible to penicillins and cephalosporins ranged from 59% to 82%; 78% of strains were susceptible to ciprofloxacin. ESBL production was phenotypically detected in 15 (16%) Enterobacteriaceae strains, with CTX-M genes revealed in all cases. In all corresponding urine samples, CTX-M genes were also detected. The remaining 104 urine samples were negative for CTX-M genes. In none of the isolates and urine samples, carbapenemase genes were present.

The frequency of ESBL producing Enterobacteriaceae was relatively high (16%), with CTX-M genes detected in all cases in both urine and urine cultures. Rapid PCR detection of CTX-M genes directly in urine samples from women with pyelonephritis can be valuable for timely informing treatment choices.