Characterization of extended-spectrum beta-lactamases produced by Enterobacteriaceae other than Escherichia coli and Klebsiella pneumoniae isolated in University Hospital of Monastir-Tunisia

Kadri, Yosr; Haddad, Ons; Maatouk, Yassmine; Ben Nejma, Mouna; Mastouri, Maha

doi:10.21608/mid.2024.327730.2280

Characterization of extended-spectrum beta-lactamases produced by Enterobacteriaceae other than Escherichia coli and Klebsiella pneumoniae isolated in University Hospital of Monastir-Tunisia

Articles in Press

Document Type : Original Article

Authors

Department of Microbiology, Fattouma-Bourguiba University Hospital, Monastir, University of Monastir, 5000 Monastir, Tunisia

10.21608/mid.2024.327730.2280

Abstract

Background: The aims of this study were to determine the prevalence of Extended-spectrum-beta-lactamases (ESBL)-producing Enterobacteriaceae other than Escherichia coli and Klebsiella pneumoniae, to evaluate antimicrobial susceptibility patterns, and to characterize the ESBL genes involved in this resistance. Methods: This was a descriptive study carried out from December 2018 to November 2019. A total of 580 isolates were collected from Microbiology Laboratory of the University Hospital of Monastir, Tunisia. Antibiotic susceptibility to a panel of antibiotics was performed by the disk diffusion according to CA-SFM recommendations and ESBL production was detected by the double disk synergy test and E-test methods. Genes encoding ESBL (bla_TEM, bla_CTM, bla_SHV) and bla_CTX-M subgroups were identified by PCR. Results: Sixty-eight ESBL-producing Enterobacteriaceae other than E. coli and K. pneumoniae were identified among the 580 isolates, 85.3% of which were positive for at least one of the three genes (bla_TEM, bla_CTX-M, bla_SHV), with bla_TEM accounting for 73.5%, followed by bla_CTX-M (52.9%). The bacterial strains were isolated mainly from pus in nosocomial infections. bla_TEM was detected in all Proteus mirabilis isolates and in 85.0% of Enterobacter cloacae. bla_CTX-M was frequently identified in E. cloacae and bla_CTX-M-15 was the predominant subgroup among all CTX-M-1 positive isolates. About 30.9% ESBL-producing isolates harbored bla_TEM + bla_CTX-M combination with the predominant genotype found in 45.0% of E. cloacae. Conclusion: We report the increasing prevalence of ESBL-producing Enterobacteriaceae other than E. coli and K. pneumoniae, mainly due to the dissemination of bla_TEM and bla_CTX-Mgenes. ESBL-producing strains showed resistance to antibiotic classes other than beta-lactams.

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