Detection of Plasmid-mediated Extended Spectrum β-Lactamase Genes (bla CTX-M) in Enterobacteriaceae Isolated from the Oral Cavity of Patients in a Dental Clinic in Abidjan, Côte d’Ivoire

Abstract

Background: The oral cavity represents one of the most complex and densely colonized environments of the human body, harboring a diverse microbiota including bacterial and fungal communities. Antimicrobial resistance has emerged as a pressing global health concern, with particularly severe implications for low-resource settings. Aims: This study aimed to assess the antibiotic resistance profiles of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae strains isolated from the oral cavity. Methodology: samples were collected from patients presenting with dental disorders for the isolation and characterisation of ESBL-producing Enterobacteriaceae from the oral cavity. Plasmid DNA was extracted using the phenol-chloroform method, and conventional PCR was employed to detect the presence of plasmid-borne resistance genes bla CTX-M-2, bla CTX-M-8, and bla CTX-M-9. Results: Four Enterobacteriaceae strains were successfully isolated and characterized, corresponding to an isolation rate of 5.40% (4/74). Among these, 60% harbored the bla CTX-M-2 and bla CTX-M-8 resistance genes. The bla CTX-M-9 gene was not detected in any of the isolates. Conclusion: Although uncommon in the oral cavity, the emergence of Enterobacteriaceae in this niche may represent a potential public health concern. The presence of ESBL-producing strains could contribute to therapeutic failures or limited treatment options, particularly if antibiotic prescribing guidelines are not adequately followed by healthcare professionals.