Antimicrobial susceptibility pattern and molecular characterization of ESBLs Salmonellae enterica isolated from patients attending hospitals in Northeast Nigeria

Document Type : Original Article


1 Department of Medical Microbiology, Abubakar Tafawa Balewa University

2 Department of Microbiology, Faculty of Sciences. Bauchi State University, Gadau, Bauchi state

3 Department of Peadiatrics College of Medical Sciences, Abubakar Tafawa Balewa University Teaching Hospital Bauchi, Bauchi State.

4 Department of Public Health, Faculty of Health Sciences, National Open University of Nigeria, Cadastral Zone Jabi, Abuja, Nigeria.


Background:  Salmonella enterica is a major cause of enteric fever worldwide resulting in thousands of deaths each year. This study aims to identify and characterize ESßLs-producing Salmonella enterica strains isolated from patients attending hospitals in Northeast Nigeria. Material and methods: In this cross-sectional analytical study, about 669 specimens of stool and blood were collected from patients aged between zero to 70 years, presenting with fever and gastrointestinal symptoms at three selected health facilities in Northeast Nigeria. The research was conducted from September 2020 to February 2021. A self-administered questionnaire was used to obtain demographic information from the subjects. Samples were cultured under standard microbiological protocols. Isolates obtained were identified using biochemical as well as polymerase chain reaction (PCR) targeting the 16S rRNA gene. A double disk diffusion synergy test was used to phenotypically evaluate the presence of ESßLs production. ESßLs genes were detected using multiplex PCR, amplicon size obtained was compared with 1kb ladder. Results: A total of nineteen (19) Salmonella enterica were discovered in the study, indicating a prevalence rate of 2.8%. These strains were resistant to at least three antibiotics, including Amikacin, Ampicillin, and Tetracycline. Phenotypic testing revealed ESßL activity in all 19 Salmonella enterica strains, but only 2 (10%) contained ESßL genes, as discovered in molecular analysis. The ESßLs genes determined were CMY-2, CTXM-1, and SHV. Conclusion: This study revealed burden of antimicrobial resistance and ESßLs genes in Salmonella enterica despite its low prevalence. Hence, screening for ESßLs in pathogenic bacteria is necessary in healthcare facilities.


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