Phenotypic and genotypic characterization of extended-spectrum beta-lactamase-producing Enterobacteriaceae in a Moroccan hospital

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) is a major public health problem in hospitals and in the community. The objective of this work was to describe the epidemiology of ESBL-E , to study their resistance profile and to determine the genes encoding the ESBL phenotype. This is a retrospective study conducted in the bacteriology laboratory of the Mohamed V Military Training Hospital in Rabat, and covering all isolates of Enterobacteriaceae from 1 January 2018 to 31 December 2020. The molecular study of ESBL genes involved a representative sample of all ESBL isolates. The overall prevalence of ESBLs in isolated Enterobacteriaceae (1402/10268) is 13.65 %. The urinary tract was the main site of isolation of ESBL (61 %). The bacterial species most concerned are Escherichia coli (41.9 %), Klebsiella pneumoniae (42.2 %) and Enterobacter cloacae (11.9 %). The study of antibiotic susceptibility showed a resistant profile marked mainly by 100 % resistance to first generation cephalosporins (1GC) and third generation cephalosporins (3GC), 55 % to piperacillin-tazobactam, 16 % to imipenem, and 87 % to fluoroquinolones. Molecular typing of ESBL strains showed a prevalence of CTX-M (95 %), SHV (50 %) and TEM (56 %). The CTX-M-1 and the CTX-M-9 groups were the most common (96.19 % and 7.62 % respectively), and CTX-M15 was found in 78.10 % of CTX-M-1 ESBL positive isolates. Most strains had more than two coexisting resistance genes. The prevalence rate of ESBL-E is critical, and preventive action at different levels (prescriber, biologist, hospital, patient, etc.) are necessary in order to limit their spread and to manage a better therapeutic strategy.