Antimicrobial resistance and virulence profiles of staphylococci isolated from clinical bovine mastitis

• Published in: Frontiers in microbiology 2023-06, Vol.14, p.1190790-1190790
• Main Authors: Yang, Feng, Shi, Wenli, Meng, Na, Zhao, Yiyu, Ding, Xuezhi, Li, Qinfan
• Format: Article
• Language: English
• Subjects: antimicrobial resistance; bovine mastitis; coagulase-negative staphylococci; Microbiology; Staphylococcus aureus; virulence
• ISSN: 1664-302X; 1664-302X
• DOI: 10.3389/fmicb.2023.1190790

Staphylococci, mainly including and coagulase-negative staphylococci (CNS), are one of the most common pathogens causing bovine mastitis worldwide. In this study, we investigated the antimicrobial resistance and virulence profiles of staphylococci from clinical bovine mastitis in Ningxia Hui Autonomous Region of China. Antimicrobial resistance was determined by disc diffusion combined with -test method. Genes of antimicrobial resistance and virulence factors were determined by PCR. A total of 332 staphylococcal isolates were confirmed from 1,519 mastitic milk samples, including 172 and 160 CNS isolates. Fifteen CNS species were identified, with being the most frequent found (49.4%), followed by (13.8%). Noticeably, 2 isolates were found among the CNS isolates. To our knowledge, this is the first report documenting the presence of from bovine mastitis in China. The and CNS isolates showed high resistance against penicillin, followed by erythromycin and tetracycline. Multidrug resistance was found in 11.6 and 16.3% of the and CNS isolates, respectively. Resistance to penicillin was attributed to the presence of Z, erythromycin resistance to (alone or combined with ) and tetracycline resistance to K (alone or combined with ). Notably, one isolate and one isolate were both methicillin-resistant and positive. Additionally, all isolates carried the adhesin genes , , , and , and most of them contained and . Conversely, only a few of the CNS isolates carried A, , and A. Regarding toxin genes, all isolates harbored , and most of them were positive. The - , , , , , , , , , , and were also detected with low frequencies. However, no toxin genes were observed in CNS isolates. This study reveals high species diversity of staphylococci from clinical bovine mastitis in Ningxia Hui Autonomous Region of China. The findings for the genetic determinants of antimicrobial resistance and virulence factor provide valuable information for control and prevention of staphylococcal bovine mastitis.