Long-term occurrence of multiple antimicrobial drug resistant Klebsiella pneumoniae isolates harboring virulent potential in a tertiary hospital from Brazil.

Klebsiella pneumoniae strains are globally associated with a plethora of opportunistic and severe human infections and are known to spread genes conferring antimicrobial resistance. Some strains harbor virulence determinants that enable them to cause serious disease in any patient, both in the hospital and in the community. The aim of this study was to determine the frequency of antimicrobial resistance and virulence traits (by gene detection and string test) among 83 K. pneumoniae isolates obtained from patient cultures of a scholar tertiary hospital in the Midwestern Brazil (Brasília, DF). Antimicrobial susceptibility analysis showed that 94% (78/83) of the isolates presented one of the following resistance profiles: resistant (R, 39), multidrug-resistant (MDR, 29), or extensively drug-resistant (XDR, 10). Several MDR and XDR strains harbored multiple virulence genes and displayed hypermucoviscous phenotype. These characteristics were observed among isolates obtained throughout all the sample collection period (2013 - 2017). The K2 serotype gene, a molecular marker of hypervirulence, was detected in three isolates, one of which classified as XDR. Sequence typing revealed the occurrence of isolates belonged to high-risk (ST13) and multiple resistance-spreading clones (ST105). Thus, our findings showed the occurrence of virulent potential isolates that also presented MDR/XDR phenotypes from 2013 to 2015. This study also indicates the probable convergence of virulence and resistance since at least 2013 in Brazil.