Shiga Toxin-producing Escherichia coli in Mastitis: An international perspective

Authors: MURINDA, SHELTON - California Polytechnic State University; Ibekwe, Abasiofiok - Mark; RODRIGUEZ, NORA - California Polytechnic State University; QUIROZ, KARINA - California Polytechnic State University; MUJICA, ALEXANDER - California Polytechnic State University; OSMON, KAYLA - California Polytechnic State University

Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2019
Publication Date: 4/10/2019
Citation: Murinda, S.E., Ibekwe, A.M., Rodriguez, N.G., Quiroz, K.L., Mujica, A.P., Osmon, K. 2019. Shiga Toxin-producing Escherichia coli in Mastitis: An international perspective. Foodborne Pathogens and Disease. 16(4):229-243. https://doi.org/10.1089/fpd.2018.2491.
DOI: https://doi.org/10.1089/fpd.2018.2491

Interpretive Summary: There is a critical and urgent need to control mastitis infection that affects a high proportion of dairy cows worldwide. However, many studies have not been testing for pathogenic E. coli detection, and as such, the incidence of pathogenic E. coli in mastitis remains underdiagnosed and underreported. Mastitis differs from most other animal diseases in that several diverse bacteria are capable of invading and infecting the udder, multiply there, and produce harmful substances that result in inflammation, reduced milk production, and altered milk quality. Raw milk is one of the products promoted as a “health food.” This results in milk consumption by individuals who may have lowered immunity such as the very young, very old, immuno-compromised people, or those with specific dietary needs. In this review, we focus on pathogenic E. coli which has low infectious doses. Due to these low infectious doses, there are specific concerns especially among those with lowered immunities. We highlight the threats to human health posed by consumption of milk and dairy products infected by pathogenic E. coli with a theoretical model for transmission of pathogenic E. coli between dairy cows and the environment, and worldwide prevalence of pathogenic E. coli in mastitis. Finally, we present types, prevalence rates, and ranking of pathogenic E. coli isolated from mastitis worldwide. This information will be of interest to US-Department of Agriculture (USDA), US-Environmental Protection Agency (USEPA), the World Health Organization (WHO), and the Dairy Farmers of America.

Technical Abstract: 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.