Shiga Toxin-Producing Escherichia coli in Mastitis: An International Perspective

The pathogen profile of Escherichia coli mastitis reveals a complex etiology involving commensal, environmental, and other distinct E. coli pathotypes such as enteropathogenic E. coli and of recent, Shiga toxin-producing E. coli (STEC) have been associated with bovine intramammary infections (IMI). Many researchers have not been testing for STEC and focused on E. coli detection without further subtyping, and as such, the prevalence of STEC in mastitis remains underdiagnosed and underreported. Owing to the dearth of information on STEC involvement in IMI, this review provides an international perspective on the prevalence of STEC in mastitis. In addition, predominant serotypes, ancillary virulence factors, and antimicrobial resistance profiles of STEC isolated from mastitis cases were summarized. This information is important for public health policy since STEC impact both animal health and human welfare. Importantly, the low infectious doses of STEC are a major concern to public health. The review highlights the need for further surveillance to ascertain the potential for environmental contamination and food chain security by STEC from bovine mastitis, and emphasizes appropriate, science-based mitigation approaches for prevention or control.