High Prevalence of ST502 Carrying an OXA-24 Carbapenemase gene in Carbapenem-Nonsusceptible Isolates in Romania.

can cause difficult-to-treat infections because it can acquire extensive antimicrobial resistance mechanisms. We aim to describe the antimicrobial resistance pattern and the genetic basis of carbapenem-nonsusceptible isolates in a University Hospital in Romania, a country where multidrug-resistant is widespread. We collected 104 consecutive meropenem-nonsusceptible isolates from 104 patients (36% female, mean age [SD] of 63 [16] years) between May 2015 and August 2017 from a large tertiary center in Romania. Whole-genome sequencing of representative isolates from amplified fragment length polymorphism clusters was used to determine clonality and resistance patterns. All isolates were resistant to piperacillin/tazobactam, ceftazidime, and ciprofloxacin; 88.5% to gentamicin; and 90.4% to trimethoprim/sulfamethoxazole. In contrast, 79.8% and 99.0% were susceptible to tobramycin and colistin, respectively. The only isolate resistant to colistin had an minimum inhibitory concentration (MIC) of ≥16 mg/L. The gene was detected in 79.1% and in 20.9% of the isolates. In one isolate, was copresent with . ST502 (Oxford scheme) was the most prevalent sequence type and was exclusively associated with . ST502 associated with was frequently observed in the region where carbapenem-nonsusceptible was found to be endemic. In these isolates, tobramycin and colistin might be the remaining therapeutic options. Due to differences in gentamicin and tobramycin resistance in these isolates, surveillance data should not group gentamicin, tobramycin, and amikacin together as aminoglycosides.