Different virulence genetic context of multidrug-resistant CTX-M- and KPC-producing Klebsiella pneumoniae isolated from cerebrospinal fluid

Abstract

Information regarding resistance and virulence traits of meningitis-causing enterobacteria in hospital environment remains scarce. The aim of this study was to characterize virulence and acquired resistance genes of carbapenem-resistant and/or 3rd to 4th generation cephalosporin-resistant Klebsiella pneumoniae isolated from the cerebrospinal fluid of inpatients. Antimicrobial susceptibility testing was performed by disk diffusion. The string test was performed to identify hypermucoviscous phenotype. Galleria mellonella infection model was used to evaluate the virulence profile of the isolates. Screening for virulence determinants and acquired resistance genes were performed by PCR. The blaCTX-M and/or blaKPC and/or rmtG were detected in all the isolates. Genetic virulence determinants, including mrkD, entB, iroD, fecIRA, uge, wabG, fimH, ureA, ybtS, and clb were detected in the majority of multidrug-resistant K. pneumoniae isolates. One isolate presented hypermucoviscous phenotype, and several isolates showed enhanced virulence in G. mellonella infection model. The combination of the virulence genes found here seems to support not only the known virulence genetic context among nosocomial infections-causing K. pneumoniae but also the role that clb and ybtS may play in K. pneumoniae virulence.