Prevalence and genotypic analysis of plasmid-mediated [beta]-lactamases among urinary Klebsiella pneumoniae isolates in Moroccan community

The aim of this study is to assess the prevalence and molecular characterization of the extended spectrum β-lactamases (ESBL)-producing Klebsiella pneumoniae isolated from community acquired urinary tract infections and collected in five Moroccan cities during a 2010 survey. In all, 34 (7.5%) of the 453 K. pneumoniae isolates studied were positive for an ESBL phenotype and 91.1% of these isolates were multidrug resistant. The bla CTX-M-15 (n=31) was the most frequent ESBL genes detected, followed equally by blaSHV-28 and blaSHV-12 (n=3), then blaTEM-3 , blaSHV-36 , blaSHV-110 and blaCTX-M-1 with one isolate for each (n=1). Eight isolates co-expressed more than one ESBL with blaCTX-M-15 . The non-ESBL genes detected were blaSHV-1 , blaSHV-11 , blaSHV-32 , blaSHV-26 , blaSHV-76 , blaTEM-1 , blaTEM-1b and blaOXA-1 . Plasmid-mediated AmpC β-lactamase genes, blaACT-2 , blaDHA-1 and a new β-lacatamase named blaEBC-1464 , were detected in 11.7% of isolates. Fourteen (41.1%) isolates harbored qnr genes; qnrA6 (n=1), qnrB1 (n=8), qnrB2 (n=1) and qnrS1 (n=4) types were detected. Twenty-six isolates (76.4%) were positive for aac(6[variant prime])-Ib-cr gene. Results of conjugation experiments indicated that bla CTX-M-15 , blaTEM-1b , blaOXA-1 , aac(6[variant prime])-Ib-cr and qnrB1 genes were co-transferred and that these genes were carried by a conjugative plasmid of high molecular weight. With the exception of qnrB1, all the antibiotic resistance genes were clustered in a 12-kb region. The results of this work report the genetic diversity of ESBL genes, with the CTX-M-15 enzyme being most common among ESBL-producing K. pneumoniae in Moroccan community. Furthermore, a major finding is that bla EBC-1464 detection is a first in Morocco.