Population Structure of KPC-2-Producing Klebsiella pneumoniae Isolated from Surveillance Rectal Swabs in Brazil.

KPC-producing Klebsiella pneumoniae (KPC-Kp) has become an important public health issue. The previous intestinal colonization by KPC-Kp has been an important risk factor associated with the progression to infections. The objective of this study was to assess the genetic characterization of KPC-Kp isolates recovered from human rectal swabs in Brazil. We selected 102 KPC-Kp isolates collected during 2009-2013 in 11 states. Antimicrobial susceptibility was determined by disk diffusion, E-test, and broth microdilution. The resistance and virulence genes were investigated by PCR. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The isolates were mostly resistant to β-lactams, sulfonamides, chloramphenicol, quinolones, and aminoglycosides but susceptible to fosfomycin/trometamol, polymyxin B, and tigecycline. The blaKPC-2 was mostly associated with Tn4401b. Besides that, the isolates carried blaCTX-M, blaSHV, blaTEM, and aac(6')-Ib in high frequency and aac(3')IIa and qnr genes in moderate frequency. The PFGE revealed 26 pulsotypes and MLST performed in representative strains revealed 23 sequence types, 45% belonging to clonal complex 258 (CC258). Isolates of CC258 were found in all states. Seventy percent of the 102 KPC-Kp isolates belonged to CC258-associated pulsotypes. We describe the dissemination of KPC-2-Kp associated with Tn4401b belonging to CC258 colonizing patients in Brazil, which is also prevalent in infected patients, suggesting a clear colonization-infection correlation.