Isolation and identification of Streptococcus suis from sick pigs in Bali, Indonesia

OBJECTIVE: Streptococcus suis (S. suis) is a causative agent for various syndromes in pigs. It can be transmitted to humans with typical symptoms of meningitis and death. Although human infections have been confirmed at Bali Referral Hospital, Indonesia, since 2014, the bacteria have not been isolated from pigs. Here, we provide confirmation of the presence of the bacteria in sick pigs in the province. RESULTS: Streptococcus suis was confirmed in 8 of 30 cases. The final confirmation was made using PCR and sequencing of the glutamate dehydrogenase (GDH) and recombination/repair protein (recN) gene fragments. Upon PCR serotyping, two were confirmed to be serotype 2 or 1/2. Prominent histopathological lesions of confirmed cases were meningitis, endocarditis, pericarditis, bronchopneumonia, enteritis and glomerulonephritis. The dominant inflammatory cells were neutrophils and macrophages. Further research is needed to understand the risk factors for human infection. Community awareness on the risk of contracting S. suis and vaccine development are needed to prevent human infections.