Resumo

Introduction: Co-resistance plus virulence factors determine a serious problem in the treatment of bacterial infections and provide the opportunity for selection of highly resistant and persistent bacteria. Objective: The purpose of this study was to investigate the genetic determinants of antimicrobial resistance and virulence factors in broad-spectrum cephalosporin and carbapenem-resistant Klebsiella pneumoniae isolated from inpatients in 2012, in the University Hospital of the Faculty of Medicine of Ribeirao Preto-USP (HCFMRP-USP), Brazil. Material and Methods: Twenty-seven K. pneumoniae isolates were analyzed. Clonal relatedness was established by XbaI-PFGE. The investigation of resistance determinants included PCR and sequencing for Qnr, CTX-M and KPC-encoding genes. PCR-Based Replicon Typing scheme was performed to search replicons of the major plasmid incompatibility groups (Inc) among Enterobacteriaceae. For virulence factors, PCR assays were performed to search ten virulence-encoding genes (ureA, fimH, kfuBC, uge, wabG, magA, mrkD, allS, rmpA and cf29a). Results and Discussion: Seven K. pneumoniae displayed the same pulsotype (A). Among these, two harbored only bla_KPC-2 and five bla_KPC-2 plus bla_CTX-M-2. Only one bacteria of pulsotype A did not present bla_KPC-2. Six isolates showed a closely related pulsotype (A1, A1i and A1ii) and another one showed possible clonal relatedness (A4). Besides, these last ones harbored bla_CTX-M-2 and a single bacteria harbored bla_KPC-2. In addition, all variants of pulsotypes A harbored qnrS1 and pulsotype A4 harbored qnrB19 gene. Nine other pulsotypes were detected: B (n=3), C, C3, D, E, H and I (n=1, each), F and G (n=2, each). C, G and H pulsotypes harbored bla_KPC-2; C3 and I, bla_CTX-M-2. Moreover, pulsotypes B, E and F harbored, respectively, qnrB1, qnrB2 and qnrB19 genes. IncFII plasmids were detected in 15/27 bacteria: A (n=7), A1 (n=3), A1ii, C, F, G and I (n=1, each). IncFIA (n=5), IncA/C (n=4) and IncN (n=1) plasmids were also detected. For other bacteria, other genes could be involved in the phenotype displayed. Five virulence-encoding genes were detected: ureA, fimH, uge, wabG and mrkD for all analyzed isolates. In addition, pulsotypes A1ii, C3, I (CTX-M-2 producers) and C also have the cf29a gene. Conclusion: The association of important co-resistance and virulence determinants found in K. pneumoniae is worrying and these traits could confer advantage in successful hospital infections.