Clonal Dissemination of OXA-370-Producing Klebsiella pneumoniae in Rio de Janeiro, Brazil

Enzymes of the OXA-48 family have become some of the most important beta-lactamases in the world. A new OXA-48 variant (OXA-370) was first described for anEnterobacter hormaechei strain isolated in Rio Grande do Sul (southern region of Brazil) in 2013. Here we report detection of thebla OXA-370 gene in 24 isolates belonging to threeEnterobacteriaceae species (22Klebsiella pneumoniae isolates, 1Enterobacter cloacae isolate, and 1Enterobacter aerogenes isolate) collected from five hospitals in Rio de Janeiro, Brazil, in 2013 and 2014. The isolates showed a multidrug resistance profile, and 12.5% were resistant to polymyxin B. Besidesbla OXA-370 , no other carbapenemase genes were observed by PCR, whereasbla OXA-1 was found in all isolates and 22 isolates (91.6%) possessedbla CTX-M-15 . Molecular typing of theK. pneumoniae isolates by pulsed-field gel electrophoresis (PFGE) showed the presence of two clonal groups, i.e., KpA (21 isolates) and KpB (1 isolate). KpA was characterized as sequence type 16 (ST16) and KpB as ST1041 by multilocus sequence typing (MLST). ST16 has been observed for KPC-producingK. pneumoniae in Rio de Janeiro. Plasmid analysis performed with six representative OXA-370-producing isolates showed plasmids harboring thebla OXA-370 gene in all strains, ranging from 25 kb to 150 kb. This study suggests that there is an urgent need to investigate the presence of OXA-370 and dissemination of theK. pneumoniae ST16 clone carrying this gene in Brazil.