Other Hemolytic Streptococci

Other Hemolytic Streptococci

Streptococci belonging to groups C, F, and G, and rarely H, K, O, and R can also be associated with human infections.

Group C Streptococci

Group         C streptococci      are usually pathogens of         animals. Streptococcus  equisimilisis  a  group  C  Streptococcus,  which   can cause occasional infections in humans. S. equisimilis resembles S. pyogenes in fermenting trehalose but differs from it by notfermenting ribose. Like S. pyogenes, it also produces SLO, strep-tokinase, and other proteins. It causes upper respiratory tract infections and also pneumonia, osteomyelitis, endocarditis, brain abscess, and puerperal sepsis.

S. equisimilis shows tolerance to treatment with penicillin;therefore patients may not respond to treatment with penicillin.

Group F Streptococci

These cocci are called “minute streptococci”. They grow on blood agar well in the presence of CO2. Streptococcus MG is a member of this group that can cause primary atypical pneumo-nia in humans. Demonstration of cold agglutinins in serum is diagnostic of primary atypical pneumonia.

Group G Streptococci    

Group G streptococci are the commensals of humans and of animals, such as monkeys and dogs. They may occasionally cause infections, such as tonsillitis, urinary tract infection, and endocarditis in humans.

Nonenterococcal Group D Streptococci

Streptococcus bovis and Streptococcus equinus are the nonentero-coccal group D streptococci, which are associated with human infections, such as urinary tract infections and rarely endocar-ditis. They are susceptible to penicillins.