AUTHOR=Liu Junjun , Wang Xin , Bi Chongliang , Mehmood Khalid , Ali Farah , Qin Jianhua , Han Zhaoqing 

TITLE=Molecular characterization of multi-drug-resistant Staphylococcus aureus in mastitis bovine milk from a dairy farm in Anhui, China

JOURNAL=Frontiers in Veterinary Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.966533

DOI=10.3389/fvets.2022.966533

ISSN=2297-1769

ABSTRACT=Mastitis is an economically important disease in the dairy industry, which is caused by various infectious pathogens. There is limited information is known about the situation of drug resistance and virulence factors of Staphylococcus aureus (S. aureus) in mastitis bovine milk in Anhui. Therefore, a total of 125 fresh milk samples from clinically mastitis-positive bovine animals were collected. The bacteria pathogens were identified via bacterial culture, Gram Staining, biochemical analysis, DNA extraction, 16s rRNA amplification, and phylogenetic analysis. Drug resistance analyses were performed through drug-resistant genes and virulence genes amplification. Results showed that a total of 24.8% (31/125) bacterial isolates were isolated and identified as S. aureus by gram straining, biochemical reactions, and 16 s rRNA genes blasting. Multiple sequence alignment analysis found that the current isolates were highly similar (96.9%~100.0%) to previous isolates. Phylogenetic analysis demonstrated that S. aureus was similar with MK809241.1 isolated from food in China and wCP030426.1 isolated from a person in USA. The bacterial isolates were detected resistant to 11 antibiotics including Penicillin G, SXT, Ciprofloxacin, Norfloxacin, Polymyxin B, Levofloxacin, Chloramphenicol, Clindamycin, Clarithromycin, Erythromycin, and Spectinomycin. Drug-resistant genes of blaZ, ermC, rpoB, and ant (4’)-la were successfully amplified. Virulence genes of hla, nuc, clfa and eta were found in S. aureus bacteria. The current study isolated S. aureus from milk samples and revealed its drug resistant situation, drug resistant genes, and virulence genes. Hence, regular monitoring of S. aureus in milk samples from dairy cows may contribute to the prevention and treatment of public health concerns bacteria in this region.