ESBL Genes, blaTEM, blaOXA, and blaSHV in Poultry Gut Bacteria: An Endemic Public Health Burden in Bangladesh

Background: In Bangladesh, the poultry industry contributes a significant role in the food sector. A vast amount of antibiotic is used as prophylaxis and growth promotion factors in farms. These unconcerned uses of antibiotics ultimately generate resistant bacteria affecting substantial adverse consequences on human health. Extended-spectrum b-lactamase (ESBL) genes are responsible for inactivation of antibiotics containing b-lactam ring, namely, penicillin, cephalosporins, monobactams, and carbapenems. Objectives: This study was designed to analyse the distribution of three ESBL genes and associated antimicrobial susceptibility profile of poultry gut bacteria. Methods: This study was designed to analsze the distribution of three ESBL genes and associated antimicrobial susceptibility profile of poultry gut bacteria. Poultry feces were collected and cultured on cysteine lactose electrolyte deficient (CLED) agar and Salmonella-Shigella (SS) agar to differentiate various isolates based on colony characteristics. Identification of the isolates was made by convention biochemical tests, analytical profile index (API-20E), and 16S rRNA sequence analysis. Antibiotic susceptibility test was done by disc diffusion method using 17 antibiotics from seven groups. Subsequently, polymerase chain reaction (PCR) was employed with a specific primer to identify respective ESBL genes (blaTEM, blaSHV, blaOXA). All data were analysed by SPSS. Results: A total of 113 isolates were identified from 85 poultry feces tested. Most of the bacteria belonged to Enterobacteriaceae family, notably Proteus spp., E. coli, Klebsiella spp., Salmonella spp., and Enterobacter spp. Different bacteria were detected, namely, Kurthia populi, Cronobactersp, and Eikenella corrodens.   Most of the poultry isolates were resistant against more than one group of antibiotics. ESBL gene, blaTEM gene was identified most frequently (53.9%), followed by blaOXA (52.2%), and blaSHV (23%). Higher phenotypic resistance was observed in isolates carrying ESBL genes. Conclusion: This study revealed a very high frequency of three ESBL genes with their phenotypic resistance- capacities in Bangladeshi poultry gut microbiota. Excess uses of antibiotics in local poultry farms may result in the emergence of antibiotic resistance that is imposing public health threatening in Bangladesh. Bangladesh Med Res Counc Bull 2021; 47(2): 165-174