Prevalence and distribution of bla(CTX-M), bla(SHV), bla(TEM) genes in extended- spectrum β- lactamase- producing E. coli isolates from broiler farms in the Philippines

BACKGROUND: Antimicrobial resistance is a worldwide problem causing serious health threats. Escherichia coli is one of the most important bacteria that causes resistance problem. These bacteria produce an enzyme called extended-spectrum β-lactamase (ESBL) that allows it to become resistant to a wide variety of penicillins and cephalosporins. Currently, no information or published studies on ESBL-producing E.coli in broilers are available in the Philippines. This cross-sectional study was conducted to determine the prevalence and distribution of extended-spectrum β-lactamase (ESBL)-encoding genes, bla(CTX-M), bla(SHV), and bla(TEM), among E. coli isolates from broiler farms in Luzon, Philippines. RESULTS: Results showed a farm prevalence of 66. 67%. A total of 69 (44.23%) ESBL-producing E. coli were isolated from boot swabs and cloacal swab samples from broiler farms. All major bla(CTX-M) groups except bla(CTX-M-25) group were identified in the isolates. The most prevalent group was bla(CTX-M-1), 72.46% (CI: 60.38–82.54%), followed by bla(CTX-M-2), bla(CTX-M-9) group and bla(CTX-M-8). The bla(TEM) and bla(SHV) genes were identified in 57.97 and 27.54% of isolates, respectively. The bla(CTX-M) and bla(TEM) were the most common gene combinations (33.33%). Coexistence of bla(CTX-M) types was observed in 50 (73.53%) isolates. CONCLUSION: This study shows the high prevalence, diversity of patterns and coexistence of ESBL genes in the E. coli isolates from cloacal and boot swabs from broiler farms which pose risks of possible transmission to the environment, other animals and human.