Streptococcus suis

Streptococcus suis is a peanut-shaped, Gram-positive bacterium, and an important pathogen of pigs. Endemic in nearly all countries with an extensive pig industry, S. suis is also a zoonotic disease, capable of transmission to humans from pigs. In 2023, it was first reported from fish, isolated during a lethal outbreak in farmed snakeskin gourami (Trichopodus pectoralis). Humans can be infected with S. suis when they handle infected pig carcasses or meat, especially with exposed cuts and abrasions on their hands. Human infection can be severe, with meningitis, septicaemia, endocarditis, and deafness as possible outcomes of infection. Fatal cases of S. suis are uncommon, but not unknown. Penicillin is the most common antibiotic used in treatment of S. suis infection; in cases with cardiac involvement (endocarditis), gentamicin should also be given for synergistic effect.