High Prevalence of bla CTX-M Extended Spectrum Beta-Lactamase Genes in Klebsiella pneumoniae Isolates from a Tertiary Care Hospital: First report of bla SHV-12,bla SHV-31,bla SHV-38,and bla CTX-M-15 in Brazil

Abstract

The aim of this study was to investigate the presence and prevalence of bla_TEM, bla_SHV, and bla_CTX-M and bla_GES-like genes, responsible for extended spectrum beta-lactamases (ESBLs) production in clinical isolates of Klebsiella pneumoniae collected from a Brazilian tertiary care hospital. Sixty-five ESBL producing K. pneumoniae isolates, collected between 2005 and 2007, were screened by polymerase chain reaction (PCR). Identification of bla genes was achieved by sequencing. Genotyping of ESBL producing K. pneumoniae was performed by the enterobacterial repetitive intergenic consensus-PCR with cluster analysis by the Dice coefficient. The presence of genes encoding ESBLs was confirmed in 59/65 (90.8%) isolates, comprising 20 bla_CTX-M-2, 14 bla_CTX-M-59, 12 bla_CTX-M-15, 9 bla_SHV-12, 1 bla_SHV-2, 1 bla_SHV-2a, 1 bla_SHV-5, and 1 bla_SHV-31 genes. The ESBL genes bla_SHV-12, bla_SHV-31, and bla_CTX-M-15, and the chromosome-encoded SHV-type beta-lactamase capable of hydrolyzing imipenem were detected in Brazil for the first time. The analysis of the enterobacterial repetitive intergenic consensus-PCR band patterns revealed a high rate of multiclonal bla_CTX-M carrying K. pneumoniae isolates (70.8%), suggesting that dissemination of encoding plasmids is likely to be the major cause of the high prevalence of these genes among the K. pneumoniae isolates considered in this study.