Multiple Antibiotic Resistance among Escherichia coli Isolated from Selected Abattoirs in Northwestern Nigeria

Escherichia coli is one of the major contaminants in the abattoir because of its frequent  association with both living and cattle carcasses. It is used as indicator for both contamination and  prevalence of antibiotic resistance. Samples were collected from water, effluent and swabs of various  surfaces from selected abattoirs in northwestern Nigeria. They were analyzed using microbiological  techniques for isolation of E. coli. Fifty of these bacteria were randomly selected and tested against nine  selected antibiotics: amoxicillin-clavulanic acid (30 µg), cefoxitin (30 µg), gentamicin (10 µg), tetracycline  (30 µg), ciprofloxacin (5 µg), sulfonamides and trimethroprim (25 µg), chloramphenicol (30 µg),  vancomycin (30 µg) and erythromycin (15 µg)to determine their level of resistance to each of the  antibiotics using disc diffusion method. The results showed highest resistance of E. coli isolates to  vancomycin (92%), followed by amoxicillin-clavulanic acid (76%) and erythromycin (76%). None of the  isolates was resistant to gentamicin and ciprofloxacin. However, resistance against chloramphenicol (8%),  sulfonamides and trimethroprim (16%), and cefoxitin(24%) were low. Multiple antibiotic resistant index  (MARI) was determined and 46 (92%) of the isolates were found to be multi-drug resistant. Indiscriminate  use of antibiotics for treatment, as growth promoter in animal foods and poor hygiene practices could be  responsible for this level of resistance.  The high resistant E. coli could be a significant threat to public  health due to the risk of transferring the bacteria into food chain hence, monitoring antimicrobial resistance  and virulence is indispensable.