Isolation, identification, and pathogenicity analysis of Staphylococcus devriesei associated with subclinical bovine mastitis

Abstract

Background Bovine mastitis is a disease that is highly detrimental to the global dairy industry and poses risks to both consumer health and aquaculture economics. Microbial infections, particularly those caused by Staphylococcus aureus and coagulase-negative Staphylococcus, are the primary causes of bovine mastitis. This study aimed to isolate and identify the coagulase-negative Staphylococcus strain causing subclinical bovine mastitis and to investigate its pathogenicity and potential effects on the host using a mouse model. S. devriesei was isolated from the milk samples of mice with recessive mastitis using routine bacteriological methods. We observed the morphological structure, physicochemical properties, related pathological changes and translocation of the bacterium. Bacterial endotoxins and related inflammatory factors were detected to evaluate systemic lesions. Results Based on 16s rRNA sequencing results, the isolated S. devriesei strain, S. devriesei CL, is a gram-positive and γ hemolytic staphylococcus, with a genome length of 2,385,004 bp and 2,189 predicted genes, and it was most closely related to S. taiwanensis and S. haemolyticus. S. devriesei CL（S. devriesei China Lanzhou） has an incubation period of 4 h, reaching the logarithmic phase after 4–10 h and plateauing after 10 h at the optimal growth temperature and pH of 30 ℃ and 7, respectively. S. devrieseiCL was not resistant to the most commonly used antibiotics, and its growth was significantly influenced by conventional disinfectants. S. devriesei CL was associated with chronic bovine mastitis and systemic inflammation. The disease was associated with a high expression of lipoteichoic acid and seven other inflammatory factors. Conclusion In conclusion, this study is the first comprehensive investigation of the physical and chemical properties and pathogenic mechanism of S. devriesei in China. It provides valuable insights into the pathological changes caused by this bacterium, serving as a theoretical basis for understanding the disease, estimating economic losses, and developing prevention and treatment strategies.