Prevalence and molecular characterization of carbapenemase-producing Enterobacterales in an outbreak free setting in a single hospital from Uruguay.

Abstract Objectives Characterize all the carbapenemase-producing enterobacteria (CPE) isolates obtained from an outbreak free setting in Uruguay. Methods We studied 12 CPE isolated from the Hospital de Clinicas between 2012 and 2016. Bacterial identification and antibiotic susceptibility testing were performed using VITEK®2, SENSITITRE and agar dilution, respectively. Resistance genes and mobile genetic elements were identified by PCR and sequencing. Multilocus sequence typing was done to Klebsiella pneumoniae. Plasmid conjugation was assessed, the plasmid size was estimated by S1-PFGE and plasmid incompatibility groups were sought by PCR. Results We isolated 12/8364 CPE from urine, blood culture, wound, peritoneal fluid and punch samples. NDM-1 was the most prevalent carbapenemase, followed by VIM-2 and KPC-2; all isolates were resistant to gentamicin, cefotaxime, ceftazidime, trimethoprim-sulfamethoxazole, ciprofloxacin and imipenem, and susceptible to fosfomycin. We characterized six class 1 integrons: dfrA12-orfF-aadA2; aacA4-blaOXA-2-orfD; aadB-aadA2; dfrA1; aadB-blaOXA-10-aadA1 and blaVIM-2-dfrA7. Association between various aminoglycosides, β-lactams and fluoroquinolones resistance genes were observed, some of them located in transferable plasmids belonging to the incompatibility groups IncC, IncHI1 and IncM1. We described a new composite transposon, assigned as Tn6935, including blaNDM-1 flanked by two directly-oriented copies of a Tn3-like element ISKox2-like family transposase. The sequence types of K. pneumoniae were ST11, ST14 and ST661. Conclusions The presence of CPE is sporadic and could be due to the measures taken by the Public Health Committee. Nevertheless, the coexistence of several resistance mechanisms and their presence in conjugative plasmids and high-risk clones is worrisome.