Identification of a New Serovar of Salmonella enterica in Mediterranean Buffalo Calves (Bubalus bubalis)

Simple Summary The presence of Salmonella enterica in buffalo (Bubalus bubalis) farms is a cause for great concern, as it is responsible for serious economic losses and is a zoonotic agent capable of contaminating the mozzarella production chain. Salmonella induced disease mainly affects buffalo calves and is characterized by severe gastrointestinal lesions, profuse diarrhea, severe dehydration, septicemia and death; in adults it can also induce termination of pregnancy. The main source of infection in the herd is asymptomatic elderly animals that release high bacterial charges through the feces. Other sources of infection are contaminated fodder and water; the infection can also be transmitted by rodents, wild birds, insects and humans. There are several serotypes of Salmonella reported in the literature capable of infecting the buffalo. This work describes an important outbreak of Salmonellosis that occurred in young subjects of a buffalo farm located in the province of Salerno. It is supported by a new serotype of Salmonella so far never described and included in the Kauffmann-White classification. This case report describes for the first-time cases of severe gastroenteritis in water buffalo calves due to a new serovar of Salmonella enterica. The study was carried out on fecal matrix collected from live water buffalo calves that showed profuse diarrhea, severe dehydration and fever, exhibiting a systemic course. Culture and molecular investigations identified the pathogens isolated from intestinal contents as two Salmonella serovars, Salmonella enterica enterica O:35 and a new serovar of Salmonella enterica. The isolates showed multi-drug resistance. Timely diagnosis associated with a targeted antimicrobial treatment were found to be sufficient for the survival and recovery of the infected animals. Herd vaccines prepared from isolated pathogens were used to prevent further deaths of the calves.