Resumo

The detection of multidrug resistant (MDR) microorganisms associated with several virulence mechanisms constitutes a great risk to public health. These bacteria can cause severe infections with few treatment options available, leading to difficulty in effective clinical improvement of the infected patients. The aim of this study was to investigate the presence of virulence genes in isolates of KPC-2 producing Klebsiella pneumoniae. The isolates included in the study (KPN529, KPN530, KPN531, KPN532, KPN535 and KPN537) were obtained from surveillance cultures from patients admitted to the ICU of a public hospital in Recife, in December 2011. Virulence genes Kfu (iron uptake system), rmpA (mucoviscosity), fimH (type I fimbriae), mrkD (type III fimbriae), uge (urease operon), wabG (synthesis of lipopolysaccharide), magA (capsular serotype K1) and wxy (capsular serotype K2) were investigated by PCR using specific primers. The amplicons were purified, sequenced and compared to sequences available in GenBank. All isolates showed the type I fimbriae gene fimH and the type III gene mrkD, related to the synthesis of biofilm, as well as the wabG chromosomal gene, responsible for the biosynthesis of lipopolysaccharide-LPS. The uge gene was detected in two isolates (KPN531 and KPN532). The wxy K2 capsular antigen gene was also observed in all the isolates. Serotype K1 magA and rmpA genes were observed in any of the isolates. Capsular types considered endemic in hospitals are K1 to K6, with a higher incidence of serotype K2, consistent with the results presented here. In addition, serotype K2 is associated with the phenotype of hypermucoviscosity, which can promote invasive infections, such as liver abscesses. The presence of mrkD gene may also limit the therapeutic options available, since the synthesis of biofilm often reduces the action of antimicrobial agents. The presence of several virulence determinants in MDR isolates can enhance both the power setting and the ability to survive in biotic and abiotic habitats, rendering increased advantage to such isolates to settle in the hospital environment.