Prevalence and types of extended spectrum β-lactamases among urinary Escherichia coli isolates in Moroccan community

This study was designed to characterize extended-spectrum-beta-lactamases (ESBL) produced by Escherichia coli isolates causing community urinary tract infections over a 2-year period (2010 and 2011) in a Moroccan large geographical region. Molecular characterization was done by using PCR and sequencing of the beta-lactamases genes and plasmid-mediated quinolone resistance determinants. Among 1174 isolates, 49 (4.1%) were ESBL producers. The bla(CTx-M-15) (n = 31) was the most frequent ESBL gene detected, followed by bla(CTx-M-1) (n = 5), bla(SHv-12) (n = 6), bla(PER-2) (n = 3), then bla(TEM-3), bla(TEM-20), blaT(EM-158), bla(SHV-27), bla(SHV-28), bla(SHV-36), bla(SHV-125), bla(CTx-M-14) and bla(CTx-M-27) with one isolate for each. The non-ESBL genes detected were bla(TEM-70) (n = 1), bla(TEM-176) (n = 1), bla(TEM-104) (n = 6), bla(TEM-1) (n = 15) and bla(OxA-1) (n = 12). Plasmid mediated AmpC beta-lactamases genes; bla(ACT-5) (n = 1), bla(DHA-1) (n = 2) and bla(CMY-2) (n = 4) were detected in seven isolates (14.2%). The bla(OxA-48) (n = 1) and bla(IMP-1) (n = 1) carbapenemases genes were detected among five carbapenem-resistant E. coli. Five isolates (10.2%) harboured qnr genes, qnrB1 (n = 3), qnrB2 (n = 1) and qnrS1 (n = 1) type were detected. Thirty isolates (61.2%) were positive for aac(6')-Ib-cr gene. The class 1 integron was detected in twenty two (44.8%) isolates. Phylogenetic grouping revealed that 22 (44.8%) isolates belonged to group A, while 15 (30.6%), 11(22.4%) and 1 (2%) belonged to B2, D and B1. Results of conjugation experiments indicated that bla(CTx-M-15), bla(TEM-1,) bla(OxA-1), aac(6')-Ib-cr and qnrB1 genes were co-transferred and that these genes were carried by a conjugative plasmid of high molecular weight. The results of this work reports the genetic diversity of ESBL genes, with the CTX-M-15 enzyme being the most common among ESBL-producing E. coli in Moroccan community. (c) 2013 Elsevier Ltd. All rights reserved.