Circulation of <i>Streptococcus agalactiae</i> ST103 in a Free Stall Italian Dairy Farm
Filippo Barsi, Elena Carra, Matteo Ricchi, Gisella Gnali, G. Pisoni, Simone Russo, Anita Filippi, N. Arrigoni, Ruth N. Zadoks, Chiara Garbarino
Abstract
Streptococcus agalactiae is an important pathogen in humans and cattle. Bovine mastitis caused by this bacterium and its control are generally associated with contagious transmission between animals. More recently, the presence of a fecal-oral transmission cycle in cattle has been proposed, linked to the ability of some S. agalactiae strains to survive in the bovine gastrointestinal tract and environment. Based on analysis of 1,316 specimens from cattle and their environment on a single dairy farm, we demonstrate the presence of sequence type 103 (ST103), which may have an environmental mode of transmission. This possibility was supported by the fact that the mastitis outbreak could not be controlled through measures to prevent contagious transmission alone and required additional environmental hygiene measures to be brought to a halt. This case study highlights that measures to control animal disease need to evolve alongside the microorganisms that cause them.