[Comparison of methods for the isolation of beta-hemolytic streptococci].

Throat swabs from 334 patients, submitted to the clinical laboratory of the Institute of Infectious Diseases (Siena University), for isolation of beta-hemolytic streptococci, were inoculated and incubated aerobically and anaerobically. Beta-hemolytic streptococci were identified in 117 (35%) cases, including 77 group A streptococci. Group A streptococci were recovered significantly more often with anaerobic incubation than with aerobic incubation (77 versus 53 cases: P less than 0.01). Non-group A beta-hemolytic streptococci also were recovered significantly more often with anaerobic incubation (40 versus 22; P less than 0.01). We conclude that anaerobic incubation for throat cultures is superior to incubation in normal air for detection of beta-hemolytic streptococci.