Abstract
A cross-sectional study was conducted in small, medium, and large-scale dairy farms of Holeta district to isolate, identify, and antimicrobial susceptibility profile of Escherichia coli O157 : H7 in raw milk of dairy cattle. A total of 210 lactating cows were selected for raw milk samples, and 19% (40/210) were found to be positive for E. coli whereas 5.2% (11/210) were confirmed as E. coli O157 : H7 positive using the Escherichia coli O157 latex test. Accordingly, all E. coli was highly susceptible to Ciprofloxacin (100%), Gentamycin (100%), Oxytetracycline (100%), and Tetracycline (63.63%). Furthermore, the resistance of 72.73%, 54.54%, 54.54%, and 45.45% was developed to Cefoxitin, Sulphamethoxazole, Cloxacillin, and Streptomycin, respectively. Factors such as parity, age, body condition, herd size, milk yield, udder hygiene, and udder lesion showed a statistically significant ( p < 0.05 ) association with the occurrence of E. coli infection in dairy cattle. In conclusion, in this study, a higher prevalence of Escherichia coli O157 : H7 and its drug susceptibility profile is an alarm for the health of the public, and awareness creation to the farm owners and the community is recommended.
Highlights
Milk and dairy products are consumed by billions of people around the globe daily and have valuable nutritional factors such as proteins, lipids, minerals, and vitamins [1, 2]
E. coli isolates grown on MacConkey agar, Eosin Methylene Blue (EMB) Agar, and Sorbitol MacConkey Agar were identified based on different characteristics on biochemical tests [18]
Simmon’s citrate agar, sugar fermentation on Triple Sugar Iron Agar, Indole Production, VogesProskauer, and Methyl red tests were performed. e isolates of the above media were tested by Triple Sugar Iron Agar (TSI) slant culture by stab method, and after 48 hours of incubation at 37°C, yellow slant with yellow butt, presence of gas bubbles, and absence of black precipitate in the butt were observed which is indicative of E. coli
Summary
Milk and dairy products are consumed by billions of people around the globe daily and have valuable nutritional factors such as proteins, lipids, minerals, and vitamins [1, 2]. Foodborne diseases are an important challenge in public health; in particular, developing countries are largely affected because of the prevailing poor food handling and sanitation practices, inadequate food safety laws, weak regulatory systems, and lack of financial resources [4, 5]. Milk and other dairy products are mostly contaminated with E. coli O157 : H7 during direct exposure to feces due to poor handling systems and causes intestinal or extraintestinal disease [10, 11]. E high prevalence of E. coli O157 : H7 in dairy products may be due to improper milking hygiene, poor house hygiene, lack of postmilking teat dipping and practicing of milk by contact labors use of lubricant, and absence of order in milking cows of different ages. Its occurrence was high in dairy farms without being noticeable in farm treatment [12]
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