Genome Comparison and Phylogenetic Analysis of Mastitis-Related Staphylococci with a Focus on Adhesion, Biofilm, and Regulatory-Related Genes

Abstract

Bovine mastitis is the costliest diseases on dairy farms and is caused by different Staphylococcus species. However, staphylococci associated with clinical mastitis infections are different from subclinical ones, indicating a complex mechanism related to bovine mastitis pathogenesis. Here, we performed genomic analyses to determine the prevalence of adhesion, biofilm, and regulatory genes in 478 staphylococcal spp. associated with clinical and subclinical mastitis deposited in public databases. The most prevalent adhesin genes were the ebpS, atl, pls, sasH and sasF genes found in both clinical and subclinical isolates. However, the ebpS gene is absent in subclinical isolates of Staphylococcus arlettae, S. succinus, S. sciuri, S. equorun, S. galinarum, and S. saprophyticus. In constrast, the coa, eap, emp, efb, and vWbp genes were present more frequently in clinical mastitis isolates and highly correlated with the presence of the icaABCD and icaR biofilm genes. We also revealed that many adhesins, biofilm, and associated regulatory genes were potentially horizontally disseminated between clinical and subclinical isolates. Taken together, our results indicate that several adhesins, biofilm, and regulatory-related genes have been overlooked in previous studies and that these virulence factors may arise in staphylococcal species not generally associated with clinical mastitis by horizontal gene transfer.