Streptococcus - stationary spherical gram-positive bacteria with a diameter of 0.8-1.0 MK, located chain.
Most streptococci are aerobes, facultative anaerobes, and some are strict anaerobes. Anaerobic streptococci - most of saprophytes, sometimes are the agents of wound infections and chronic inflammation. Streptococci do not form spores, multiply direct division and well cultivated on artificial nutrient media. Pathogen Streptococcus form a capsule.
For primary identification streptococcal use character growth on agar with blood. On this basis streptococci divided into viridans, haemolytic and non-haemolytic types. On the antigenic properties of streptococci divided into 17 serological groups (a, b, C, and so on). For a human pathogen Streptococcus group a causative scarlet fever, angina, rheumatism, rheumatoid arthritis and other Virulence streptococcal group a is caused by the presence of capsules, which prevents them from phagocytosis by leukocytes. In addition, streptococci group a and some strains of other groups produce exotoxins. Streptococci this group well withstand drying, while maintaining the viability, but losing the virulence. Streptococci are killed after warming up with t º 56º for 30 - 60 minutes Streptococci group And sensitive to the effects of sulfonamides, and antibiotics ( penicillin, as a rule, does not occur in resistance to streptomycin it develops very quickly).