Prevalence and Antimicrobial Susceptibility Profiles of Escherichia Coli Isolated from Raw Cow Milk on Selected Intensive Dairy Farms in Bishoftu, Ethiopia

Abstract Background Raw milk can serve as a vehicle for foodborne pathogens, including Escherichia coli , and may pose a public health risk, particularly where unpasteurized milk is commonly consumed. Objective This study aimed to determine the prevalence of E. coli in raw cow milk and characterize the antimicrobial susceptibility profiles of the recovered isolates from selected intensive dairy farms in Bishoftu, Ethiopia. Methods A cross-sectional study was conducted from October to May 2025 in three selected dairy farms in Bishoftu. A total of 210 milk samples were collected and examined using bacteriological and biochemical methods. Antimicrobial susceptibility was assessed using the Kirby–Bauer disk diffusion method. The susceptibility results were summarized for six antimicrobial agents. Results From 210 milk samples examined, 113 (53.8%) were positive for E. coli . The prevalence was 55.8% (53/95) at EMDID, 48.9% (22/45) at EDF, and 54.3% (38/70) at CVMA. The difference among farms was not statistically significant ( p = 0.743). Contamination was more frequent in bulk-tanker milk (80.0%, 32/40) than in individual cow milk (47.6%, 81/170; p = 0.0004). The highest susceptibility was observed to amikacin (92.0%), gentamicin (85.8%), and ceftriaxone (77.9%). Resistance was highest to ampicillin (69.9%) and trimethoprim–sulfamethoxazole (61.9%). Based on the study's reported classification, 51 isolates (45.1%) were categorized as multidrug-resistant. Conclusion E. coli was detected in more than half of the milk samples examined, and the isolates exhibited varying levels of resistance to the antimicrobial agents tested. These findings underscore the importance of hygienic milk production and handling, appropriate antimicrobial use, and continued surveillance of antimicrobial resistance in dairy production systems.