Department of Veterinary Sciences, School of Veterinary Medicine, Ambo; University, P.O. Box 19, Ambo, Ethiopia.
Department of Veterinary Laboratory Technology, School of Veterinary Medicine, Ambo University, P.O. Box 19, Ambo, Ethiopia.
Int Microbiol. 2023 Aug;26(3):513-527. doi: 10.1007/s10123-022-00317-x. Epub 2023 Jan 4.
Staphylococcus aureus (S. aureus) is a foodborne bacterial pathogens that can cause staphylococcal food poisoning and contaminate food of animal origin worldwide. The current study was conducted to estimate the prevalence and assess risk factors, hygienic quality, and antibiogram of S. aureus in raw milk and milk products of cows in Ambo and Bako towns, Ethiopia.
The overall prevalence of S. aureus in milk and milk products was 15.6% (94/601) with the highest prevalence in bulk tank raw milk (17.50%) and the lowest in "Ergo" (13.11%). High S. aureus contamination at farm level were associated with poor farm hygiene, extensive management system, medium farm size, loose housing, and less frequent removal of bedding. At the cow level, a high S. aureus isolation rate was observed in crossbred cows; cows with age equal to or greater than 5 years old, tick infestation, history of mastitis treatment, and udder washing were not practiced before milking. On the other hand, the type of container, hygiene of milk handler, and container were the major risk factors for bulk tank milk contamination with S. aureus. S. aureus counts ranging from 1.25 × 10 to 1.92 × 10 CFU/mL were detected in 28.33% of the bulk tank milk samples.. Antimicrobial susceptibility test showed higher resistance of S. aureus to amoxicillin (98.48%), oxacillin (98.48%), ampicillin (98.48%), cefoxitin (92.42%), and tetracycline (83.33%), with 43.94% of isolates showing multidrug resistance (MDR). The high prevalence of oxacillin and cefoxitin-resistant isolates, which is a possible indicator of the existence of methicillin-resistant Staphylococcus aureus (MRSA), was also noted in the current study.
Higher prevalence of S. aureus and MDR isolates in milk and milk products was detected in study areas. Therefore, to make milk and milk products safe for human consumption, hygienic handling of milk and milk products, regular surveillance of antimicrobial resistance, and prudent use of drugs are recommended.
金黄色葡萄球菌（S. aureus）是一种食源性细菌病原体，可导致葡萄球菌食物中毒，并在全球范围内污染动物源性食品。本研究旨在评估埃塞俄比亚安博和巴科镇奶牛生奶和奶制品中金黄色葡萄球菌的流行率和危险因素、卫生质量以及抗生素耐药谱。
生奶和奶制品中金黄色葡萄球菌的总流行率为 15.6%（94/601），其中散装原奶的流行率最高（17.50%），“Ergo”的流行率最低（13.11%）。农场层面金黄色葡萄球菌污染严重与农场卫生条件差、管理系统广泛、农场规模中等、畜舍通风不良以及床褥更换不频繁有关。在牛层面，杂交奶牛的金黄色葡萄球菌分离率较高；5 岁及以上、有蜱虫感染、有乳腺炎治疗史、挤奶前未进行乳房清洗的奶牛。另一方面，容器类型、挤奶工卫生和容器是散装奶中金黄色葡萄球菌污染的主要危险因素。28.33%的散装奶样中金黄色葡萄球菌计数为 1.25×10 到 1.92×10 CFU/mL。药敏试验显示，金黄色葡萄球菌对阿莫西林（98.48%）、苯唑西林（98.48%）、氨苄西林（98.48%）、头孢西丁（92.42%）和四环素（83.33%）的耐药率较高，43.94%的分离株表现出多药耐药性（MDR）。本研究还发现，耐苯唑西林和头孢西丁的金黄色葡萄球菌分离株的高检出率可能是耐甲氧西林金黄色葡萄球菌（MRSA）存在的一个指标。
在研究地区生奶和奶制品中金黄色葡萄球菌和多药耐药分离株的检出率较高。因此，为了使奶和奶制品安全食用，建议对奶和奶制品进行卫生处理，定期监测抗生素耐药性，并谨慎使用药物。
