Diversity and pathogenesis of Staphylococcus aureus from bovine mastitis: current understanding and future perspectives

Abstract

Staphylococcus aureus is a leading cause of bovine mastitis worldwide. Despite some improved understanding of disease pathogenesis, progress towards new methods for the control of intramammary infections (IMI) has been limited, particularly in the field of vaccination. Although herd management programs have helped to reduce the number of clinical cases, S. aureus mastitis remains a major disease burden. This review summarizes the past 16 years of research on bovine S. aureus population genetics, and molecular pathogenesis that have been conducted worldwide. We describe the diversity of S. aureus associated with bovine mastitis and the geographical distribution of S. aureus clones in different continents. We also describe studies investigating the evolution of bovine S. aureus and the importance of host-adaptation in its emergence as a mastitis pathogen. The available information on the prevalence of virulence determinants and their functional relevance during the pathogenesis of bovine mastitis are also discussed. Although traits such as biofilm formation and innate immune evasion are critical for the persistence of bacteria, the current understanding of the key host-pathogen interactions that determine the outcome of S. aureus IMI is very limited. We suggest that greater investment in research into the genetic and molecular basis of bovine S. aureus pathogenesis is essential for the identification of novel therapeutic and vaccine targets.

First Finding of a Methicillin-Resistant Staphylococcus aureus (MRSA) t304/ST6 from Bovine Clinical Mastitis

“…Thereby, MGEs cause gene gain and loss, and they can subsequently lead to genetic adaption to new niches [ 18 ]. Evolutionary studies of S. aureus strains have revealed that some MGEs and virulence genes are host-specific [ 19 , 20 ]. To date, several of such bovine-specific virulence factors are described, for instance some leukotoxins, which are associated with lytic activity against white blood cells.…”

Ceftiofur efficacy in the intramammary extended treatment of staphylococcal subclinical mastitis in primiparous cows

“…S. aureus and S. intermedius are prevalent coagulase-positive staphylococci species involved in bovine mastitis (Wald et al, 2019), particularly S. aureus and S. intermedium also isolated in the present study. Coagulasepositive staphylococci has been described as the most pathogenic microorganisms related to mastitis in cows and heifers in Canada and the United States (McParland et al, 2019;Campos et al, 2022). This group of bacteria often causes subclinical mastitis, with chronic evolution and refractoriness to conventional antimicrobials.…”

“…The difficulty in treating staphylococcal mastitis, particularly S. aureus, due to the high occurrence of this group of agents in bovine mastitis, the multidrug resistance to conventional antimicrobials, a set of virulence factors, and mechanisms of evasion of the pathogen's immune system have motivated programs for the early disposal of bovine females with mastitis by S. aureus, which cause a negative impact on herds (Campos et al, 2022).…”

Draft Genome Sequences and Antimicrobial Resistance Genes of Five Staphylococcus aureus Strains Isolated from Bovine Milk

“… Staphylococcus aureus continues to be recognized as one of the major and most prevalent agents of dairy cow intramammary infections worldwide ( 1 , 2 ). We report draft genome sequences of five S. aureus strains, three of which were isolated from buffalo milk and two of which were isolated from milk samples from cattle in Pakistan.…”