Isolation and Identification of Escherichia coli from raw cow milk and source of contamination in dairy farms found in and around Haramaya, Eastern Hararghe, Ethiopia

Abstract

Escherichia coli have been spread by contamination of milk through unhygienic handling of dairy workers, and unsanitary milk utensils. A cross-sectional study was conducted from July 2021 to February 2022 at in and around Haramaya, Eastern Hararghe, Ethiopia. To assess the occurrence of Escherichia coli from raw cow milk obtained from a dairy farm, assess the source of raw cow milk contamination and the extent to which milking activities and milking equipment are a cause of contamination and determine drug antimicrobial susceptibility patterns of Escherichia coli isolates. A total of 210 samples, including milk handlers, milking environment, and milk utensils swab (90), bulk milk (60), and udder milk (60) samples. To evaluate their sanitary behavior and observation, a questionnaire was created and given to dairy farm milk producers. After the samples were examined for the presence of 69 (32.9) positive samples for Escherichia coli. The statistically significant differences in the prevalence of E. coli in milk among the potential risk factors included the age of the cow (p=0.002), body condition (p=0.014), farm size (p=0.000), udder cleaning (p=0.011), and floor condition (p=0.019). All strains of E. coli were found to be sensitive to norfloxacin and chloramphenicol according to the antimicrobial susceptibility patterns used in the current investigation. All isolates of E. coli were not susceptible to spectinomycin, vancomycin, and penicillin although kanamycin (33.3%), tetracycline (34.8%), and erythromycin (23.2%) gained in this study may have been overused because of a lack of access to effective therapy or use for minor illnesses. The present study concluded that the possible source of contamination of milk obtained from swab was higher compared to that of bulk and udder milk. Also, high antibiotic resistances were found in the swab samples. The study suggested that more efforts are needed to improve milk hygiene and quality