Rasheed Hamza, Ijaz Muhammad, Ahmed Arslan, Ali Muhammad Muddassir
Department of Veterinary Medicine, University of Veterinary and Animal Sciences, 54000, Lahore, Pakistan.
Department of Veterinary Medicine, University of Veterinary and Animal Sciences, 54000, Lahore, Pakistan.
Microb Pathog. 2025 May;202:107435. doi: 10.1016/j.micpath.2025.107435. Epub 2025 Feb 26.
Mastitis is considered one of milk-producing animals' most widespread infectious diseases. The present study evaluated the prevalence of antibiotic-resistant isolates of Staphylococcus aureus (S. aureus) including methicillin-resistant S. aureus (MRSA), β-lactam-resistant S. aureus (BRSA), aminoglycoside-resistant S. aureus (ARSA), and tetracycline-resistant S. aureus (TRSA) from the udder of dromedary camels along with the associated risk factors and the antibiogram of resistant isolates. Phylogenetic analysis of antibiotic-resistant genes with NCBI sequences was performed to check their homology. A total of 384 milk samples were collected and subjected to standard microbiological procedures to isolate S. aureus. The results revealed that 177 milk samples were found positive for subclinical mastitis (SCM) out of which 101 milk samples were found positive for S. aureus. The molecular assay found the prevalence of MRSA, BRSA, ARSA, and TRSA as 48.51 %, 46.53 %, 42.57 %, and 39.60 % by targeting the mecA, blaZ, accA-aphD, and tetK genes respectively. The study isolates significant similarities to each other and to previously reported sequences from other countries that were found by in-silico analysis, indicating the possibility of pathogen transboundary transmission. This study also revealed potential risk factors that aid in the spread of mastitis in camels. Among various risk factors, the most significant were farm hygiene, physiological status of animals, type of mastitis, teat injury, use of teat dips, and milk leakage (p < 0.05). The antibiogram of antibiotic-resistant isolates of S. aureus revealed that the highest resistance was observed against penicillin followed by amoxicillin and oxytetracycline while levofloxacin was the most sensitive drug. This study highlights the high prevalence of antimicrobial-resistant S. aureus in camel mastitis. Identified risk factors provide valuable insights into management practices that contribute to disease occurrence, aiding in the development of targeted control strategies. Additionally, antimicrobial susceptibility findings offer guidance for optimizing treatment protocols to effectively manage S. aureus-induced mastitis in camels and mitigate the spread of antimicrobial resistance.
乳腺炎被认为是产奶动物中最普遍的传染病之一。本研究评估了来自单峰骆驼乳房的金黄色葡萄球菌（S. aureus）抗生素耐药菌株的流行情况，包括耐甲氧西林金黄色葡萄球菌（MRSA）、耐β-内酰胺金黄色葡萄球菌（BRSA）、耐氨基糖苷类金黄色葡萄球菌（ARSA）和耐四环素金黄色葡萄球菌（TRSA），以及相关风险因素和耐药菌株的抗菌谱。对耐药基因与NCBI序列进行系统发育分析以检查它们的同源性。共收集了384份牛奶样本，并进行标准微生物学程序以分离金黄色葡萄球菌。结果显示，177份牛奶样本被发现亚临床乳腺炎（SCM）呈阳性，其中101份牛奶样本被发现金黄色葡萄球菌呈阳性。分子检测分别通过靶向mecA、blaZ、accA-aphD和tetK基因发现MRSA、BRSA、ARSA和TRSA的流行率分别为48.51%、46.53%、42.57%和39.60%。通过电子分析发现，该研究分离株彼此之间以及与其他国家先前报道的序列具有显著相似性，表明病原体跨界传播的可能性。本研究还揭示了有助于骆驼乳腺炎传播的潜在风险因素。在各种风险因素中，最显著的是农场卫生、动物生理状态、乳腺炎类型、乳头损伤、乳头药浴的使用和乳汁泄漏（p < 0.05）。金黄色葡萄球菌抗生素耐药菌株的抗菌谱显示，对青霉素的耐药性最高，其次是阿莫西林和土霉素，而左氧氟沙星是最敏感的药物。本研究突出了骆驼乳腺炎中耐抗菌药物金黄色葡萄球菌的高流行率。确定的风险因素为有助于疾病发生的管理实践提供了有价值的见解，有助于制定有针对性的控制策略。此外，抗菌药敏结果为优化治疗方案提供了指导，以有效管理骆驼中由金黄色葡萄球菌引起的乳腺炎并减轻抗菌药物耐药性的传播。
