Rasheed Hamza, Ijaz Muhammad, Ahmed Arslan, Ali Muhammad Muddassir
Department of Veterinary Medicine, University of Veterinary and Animal Sciences, Lahore, 54000, Pakistan.
Institute of Biochemistry and Biotechnology, University of Veterinary and Animal Sciences, Lahore, 54000, Pakistan.
Vet Res Commun. 2024 Dec 28;49(1):59. doi: 10.1007/s11259-024-10628-1.
Camel mastitis especially caused by Staphylococcus aureus (S. aureus), is a major risk to animal health and milk production. The current investigation evaluated the antibiotic susceptibility and virulence factors of S. aureus isolates from subclinical mastitis in camels. A total of 384 milk samples were collected and submitted to isolate S. aureus. The S. aureus isolates exhibiting resistance to Penicillin and Cefoxitin disc on Kirby-Bauer disc diffusion method were considered as β-lactam resistant S. aureus (BRSA) and methicillin-resistant S. aureus (MRSA) which were further confirmed by PCR targeting blaZ and mecA genes, respectively. The results showed that S. aureus was found in 57.06% of subclinical (SCM) positive camel milk samples. A high molecular prevalence of BRSA and MRSA were found to be 48.51% and 46.53% respectively depicting that treating these infections is challenging due to their high resistance levels. The phylogenetic analysis revealed a significant resemblance of the study isolates with each other and with already reported sequences from different countries which shows the potential for the spread of pathogen. Virulence profiling of antibiotic resistance strains showed the presence of virulence markers (nuc and coag genes), intercellular adhesion genes (icaA, icaD), Panton-Valentine leukocidin (pvl) gene, and enterotoxin-producing genes including sea, seb, sec, and sed. In-vitro antibiotic susceptibility testing revealed that the most resistant antibiotic group was penicillin followed by aminoglycosides and cephalosporins. Drug repurposing analysis of different non-antibiotics for combination therapies with resistant antibiotics was done to combat the S. aureus isolates harboring the mecA and blaZ genes. The results revealed the synergistic effect of amoxicillin, sulfamethoxazole, gentamicin, and doxycycline with ketoprofen, amikacin with flunixin meglumine, and gentamicin with N-acetylcysteine (NAC) against study isolates. The current investigation provides the status of antibiotic-resistant strains and virulence factors of S. aureus in the udder of dromedary camels. The combinational therapy of resistant antibiotics with non-antibiotics provides a potential therapeutic option for the treatment of resistant strains.
骆驼乳腺炎，尤其是由金黄色葡萄球菌引起的乳腺炎，对动物健康和产奶量构成重大风险。当前的调查评估了从骆驼亚临床乳腺炎中分离出的金黄色葡萄球菌的抗生素敏感性和毒力因子。共收集了384份牛奶样本并用于分离金黄色葡萄球菌。在Kirby-Bauer纸片扩散法中，对青霉素和头孢西丁纸片表现出抗性的金黄色葡萄球菌分离株分别被视为β-内酰胺抗性金黄色葡萄球菌（BRSA）和耐甲氧西林金黄色葡萄球菌（MRSA），并分别通过靶向blaZ和mecA基因的PCR进一步确认。结果显示，在57.06%的亚临床（SCM）阳性骆驼奶样本中发现了金黄色葡萄球菌。BRSA和MRSA的高分子流行率分别为48.51%和46.53%，这表明由于它们的高抗性水平，治疗这些感染具有挑战性。系统发育分析显示，研究分离株彼此之间以及与来自不同国家的已报道序列具有显著相似性，这表明病原体具有传播的可能性。对抗生素抗性菌株的毒力分析表明存在毒力标记（nuc和coag基因）、细胞间粘附基因（icaA、icaD）、杀白细胞素（pvl）基因以及包括sea、seb、sec和sed在内的产肠毒素基因。体外抗生素敏感性测试显示，最具抗性的抗生素组是青霉素，其次是氨基糖苷类和头孢菌素类。对不同非抗生素与抗性抗生素联合治疗进行了药物重新利用分析，以对抗携带mecA和blaZ基因的金黄色葡萄球菌分离株。结果显示，阿莫西林、磺胺甲恶唑、庆大霉素和多西环素与酮洛芬、阿米卡星与氟尼辛葡甲胺以及庆大霉素与N-乙酰半胱氨酸（NAC）对研究分离株具有协同作用。当前的调查提供了单峰驼乳房中金黄色葡萄球菌抗生素抗性菌株和毒力因子的状况。抗性抗生素与非抗生素的联合治疗为抗性菌株的治疗提供了一种潜在的治疗选择。
