Background: Metallo-β-lactamases (MBLs) are carbapenem-hydrolyzing enzymes that give Gram-negative bacteria the exceptional ability to resist the antimicrobial onslaught of the carbapenems such as imipenem and meropenem. MBL-producing Gram-negative bacteria exist in the community and hospital environment and they put their use of the carbapenems at risk.
Aim: This study phenotypically evaluated the prevalence of MBL-positive bacteria from carbapenem resistant Gram-negative bacteria of abattoir and poultry origin.
Materials and methods: A total of 370 environmental samples comprising samples from abattoir tables, anal swabs of cow and cloacae swab samples of poultry birds were bacteriologically analyzed for the isolation of carbapenem Gram-negative bacteria. Antibiogram was determined by the modified Kirby-Bauer disk diffusion method and MBL production was confirmed using the modified Hodges test (MHT) technique. Nitrocefin sticks were used to screen the bacterial isolates for β-lactamase production.
Results: A total of 168 Escherichia coli, 141 Klebsiella species and 147 Pseudomonas aeruginosa isolates were recovered from the samples. More than 50% of the isolated Gram-negative bacteria were highly resistant to carbapenems, cephalosporins, aminoglycosides and fluoroquinolones. β-lactamase production was detected in E. coli (38%), P. aeruginosa (33%) and Klebsiella species isolates (29%). The E. coli isolates was resistant to imipenem (51%), meropenem (55.4%) and ertapenem (86.9%). Klebsiella species and P. aeruginosa showed resistance to imipenem, meropenem and ertapenem at the rates of 41.1%, 43.3%, 84.4%; and 66.7%, 60.5%, 61.2% respectively. MBL was phenotypically detected in 22 (39.9%) carbapenem-resistant E. coli isolates, 21 (45.7%) Klebsiella species isolates and 20 (38.9%) P. aeruginosa isolates.
Conclusion: Conclusively, this study reported the occurrence of MBLproducing E. coli, Klebsiella species and P. aeruginosa isolates from abattoir and poultry sources. The occurrence of MBL-producing bacteria in abattoir and poultry samples portends serious health implication for humans who depend on these animals for source of food; and this is due in part to the transmission of drug-resistant bacteria to human population.