Phenotypic and genotypic characterization of ESBL Enterobacteriaceae clinical isolates in a Moroccan hospital

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) are a major public health problem in hospitals and in the community. The objective of this work was to describe the epidemiology of ESBL enterobacteria, 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 Military Hospital of Instruction Mohamed V of Rabat, and covering all isolates of Enterobacteriaceae from 01/01/2018 to 31/12/2020. 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 essentially 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 C1G and C3G, 55% to piperacillin-tazobactam, 16% to imipenem, 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% 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.) is necessary in order to limit their spread and to manage a better therapeutic strategy.