Effects of selective media and atmosphere of incubation on the isolation of group A streptococci.
The effects of selective media and atmosphere of incubation on the isolation of group A beta-hemolytic streptococci were evaluated. Sheep blood agar medium with gentamicin (2.5 or 5.0 mug/ml) was inferior to antibiotic-free sheep blood agar medium. This resulted from the partial restriction of group A streptococcal growth on gentamicin medium. Recovery of beta-hemolytic streptococci from specimens in air, CO2, or anaerobic incubation was evaluated. The isolation of group A streptococci was equivalent in the three incubation atmospheres; however, non-group A beta- hemolytic streptococci were isolated significantly more often from specimens incubated in an anaerobic or CO2 atmosphere than from those incubated in air. Therefore, sheep blood agar medium, stabbed with a wire loop and incubated in air, is recommended for the isolation of group A streptococci from throat swabs.
D000362:Agar; D000388:Air; D000693:Anaerobiosis; D000818:Animals; D001272:Atmosphere; D001769:Blood; D002245:Carbon Dioxide; D003470:Culture Media; D005839:Gentamicins; D006801:Humans; D010614:Pharynx / Q000382:microbiology; D012756:Sheep; D013297:Streptococcus pyogenes / Q000254:growth & development / Q000302:isolation & purification*
D003470:Culture Media; D005839:Gentamicins; D002245:Carbon Dioxide; D000362:Agar