ICAR-National Dairy Research Institute (NDRI), Animal Biotechnology Centre, Animal Genomics Lab, Karnal 132001, Haryana, India.
Referral Veterinary Diagnostic and Extension Centre (Uchani Campus), Lala Lajpat Rai University of Veterinary & Animal Sciences, Hisar, Haryana, India.
Comp Immunol Microbiol Infect Dis. 2022 Jan;80:101724. doi: 10.1016/j.cimid.2021.101724. Epub 2021 Nov 20.
Bovine mastitis is a major infectious disease affecting dairy animals resulting in enormous economic losses, prolonged antibiotic treatment, reduced milk yield and death of livestock. Emergence of Methicillin-resistant Staphylococcus aureus (MRSA) among bovine mastitis is matter of concern for animal health and dairy industry. The present study was conducted to detect the distribution of virulence and enterotoxin genes among MRSA isolates from bovine mastitis. Out of 500 milk samples, 126 isolates were identified as Staphylococcus and from these only 56 were S. aureus. S.aureus were resistant to cefoxitin (75%), ceftazidime (75%), amoxicillin (71.4%), cefodaxime (67.8%), cefepime (66.1%), oxacillin (64.3%), norfloxacin (60.7%) and gentamicin (58.9%). Only 42 isolates were identified as MRSA strains among staphylococci isolates. MRSA were harbouring virulence genes; mecA (100%), coa (100%) and nuc (100%). The other virulence factors such as hlg (80.9%, 34/42), pvl (47.6%, 20/42) and spa (92.8%, 39/42) were also reported. Molecular characterisation of enterotoxin genes revealed that out of 42 tested isolates 11 were found negative (26%) for any enterotoxin gene whereas 7 (16.6%), 6 (14.3%), 18 (42.8%), 1 (2.3%), 26 (61.9%),27(64.2%),3 (7.1%) were found positive for sea, seb, sec, sed, seg, sei, and seq enterotoxin respectively.
奶牛乳腺炎是一种严重的传染病，影响奶牛，导致巨大的经济损失、抗生素治疗时间延长、产奶量减少和牲畜死亡。耐甲氧西林金黄色葡萄球菌 (MRSA) 在奶牛乳腺炎中的出现是动物健康和奶制品行业关注的问题。本研究旨在检测奶牛乳腺炎中分离的 MRSA 菌株的毒力和肠毒素基因分布。在 500 份牛奶样本中，有 126 份被鉴定为葡萄球菌，其中只有 56 份为金黄色葡萄球菌。金黄色葡萄球菌对头孢西丁（75%）、头孢他啶（75%）、阿莫西林（71.4%）、头孢地嗪（67.8%）、头孢吡肟（66.1%）、苯唑西林（64.3%）、诺氟沙星（60.7%）和庆大霉素（58.9%）耐药。在葡萄球菌分离株中仅鉴定出 42 株为 MRSA 菌株。MRSA 携带毒力基因 mecA（100%）、coa（100%）和 nuc（100%）。其他毒力因子如 hlg（80.9%，34/42）、pvl（47.6%，20/42）和 spa（92.8%，39/42）也有报道。肠毒素基因的分子特征显示，在 42 株测试的分离株中，有 11 株（26%）对任何肠毒素基因均呈阴性，而 7 株（16.6%）、6 株（14.3%）、18 株（42.8%）、1 株（2.3%）、26 株（61.9%）、27 株（64.2%）、3 株（7.1%）分别对 sea、seb、sec、sed、seg、sei 和 seq 肠毒素呈阳性。
