Multidrug Antibiotic Resistance Index and Antimicrobial Resistance Patterns of Escherichia coli in Intensive Pig Farms in Kenya

Antibiotic resistance is a major public health threat globally, rendering the treatment of human and animal infections difficult, longer and expensive. This study was carried out to determine the antibiotic resistance profiles of Escherichia coli isolated from pig farming environments in selected pig farms around Kenya. Waste water and the associated sludge together with ground surface boot sock samples were collected from preselected intensive pig farms. The samples were cultured, E. coli isolates identified using standard microbiological procedures and confirmed by Matrix Assisted Laser Desorption/Ionization Time-of Flight Mass Spectroscopy (MALDI-TOF MS). Antibiotic susceptibility testing was performed using the Kirby–Bauer disc diffusion method against Ampicillin, Amoxicillin-clavulanic acid, Gentamicin, Trimethoprim-Sulfamethoxazole, Chloramphenicol, Enrofloxacin and Cefotaxime. The highest resistance was recorded against Amoxicillin-clavulanic acid at 30.4% and the lowest was recorded for Cefotaxime at 7.1%. Multidrug resistance was observed for 25.9% of the isolates. The isolates had varied Multidrug Antibiotic Resistance (MAR) indices, but the average index was 0.33. The results suggest that there is high antibiotic exposure in the intensive pig farms that increase the selection pressure leading to development and dissemination of antibiotic-resistant E. coli among pig populations, to humans and potentially into the environment further compounding the public health threat.