General Information: Streptococcus suis is a pathogen of pigs and is responsible for a variety of diseases including meningitis, arthritis and pneumonia. These infections can have substantial economic impact within the swine industry. Occasionally this organism can infect humans causing septicemia, meningitis and endocarditis. Streptococci are Gram-positive, nonmotile, nonsporeforming, catalase-negative cocci that occur in pairs or chains. Members of this genus vary widely in pathogenic potential. Most streptococci are facultative anaerobes, and some are obligate anaerobes.