Molecular characterization of extended spectrum β-lactamase-producing Escherichia coli in a university hospital in Morocco, North Africa

Abstract

β-Lactams are among the most widely prescribed antibiotics in human medicine. However, because of their massive and usually inappropriate use, resistance to these drugs has increased markedly, especially due to extended-spectrum β-lactamase (ESBL) production. The aims of this study were to determine the prevalence of urinary Escherichia coli strains isolated from urine samples taken from patients diagnosed with urinary tract infections (UTIs), to evaluate their current antimicrobial susceptibility pattern and to look for blaSHV, blaTEM and blaCTX-M genes in these multi-drug resistant isolates. A retrospective survey was made over 3 years from 2010 to 2012. It included all uropathogenic E. coli strains isolated from urine samples taken from consulting and hospitalized patients in the Avicenne Teaching Hospital in Marrakech, Morocco. E. coli was the etiologic agent in 63% of reported UTIs due to Enterobacteriacae. In all, the prevalence of ESBL-producing E. coli reached 6% of all urinary Enterobacteriaceae isolates in 2012. The bacterial resistance rates of ESBL-producing E. coli isolates were as follows: amoxicillin/clavulanic acid (100%), trimethoprim/sulfamethoxazole (76%), gentamicin (66%), ciprofloxacin (82%) and amikacin (56%). None of these strains was resistant to carbapenems. The ESBL production patterns observed included single production of CTX-M (70%), SHV (12%) and TEM (0%). Some ESBL-producing E. coli isolates produced combinations of 2 ESBLs belonging to different groups: CTX-M+SHV (12%) and CTX-M+TEM (6%). The results of this work report, for the first time in the Marrakech region, the ESBL production pattern with CTX-M being most common among the ESBL-producing urinary E. coli. Moreover, a major finding is the production of multiple ESBL types by some urinary E. coli isolates.