Bovine mastitis caused by streptococcus uberis. Virulence factors and biofilm

Abstract

Bovine mastitis is a multifactorial disease, commonly caused by microorganisms. The pathology affects dairy farms worldwide and causes significant economic losses. Different pathogens can cause the disease and they are classified as contagious, environmental and minor pathogens. Streptococcus uberis is a ubiquitous bacterium and is considered the main environmental agent. It is a very versatile microorganism able to use host factors to survive and colonize bovine mammary gland. Different virulence factors have been reported in S. uberis strains, such as proteoglycans and various proteins, which are secreting in milk facilitating the establishment of intramammary infections. Strategies for the control of environmental agents have less impact compared to those applied for contagious agents. Furthermore, intramammary infections are associated with biofilm formation which leads to antibiotic resistance making the treatment of recurrent infections hard. Thus, different alternative control methods have been proposed, as the use of bacteriocins and immunomodulatory compounds. The present review summarizes different studies about the characterization of S. uberis virulence factors and the importance of the studies to promote and design effective and novel therapeutic approaches.