A beta-hemolytic gram positive coccus in chains from a throat culture is susceptible to bacitracin and is PYR positive. Which organism is most likely?
1Streptococcus agalactiae
2Enterococcus faecalis
3Streptococcus pneumoniae
4Streptococcus pyogenes✓ 정답
해설
Among the beta-hemolytic streptococci, susceptibility to bacitracin combined with a positive PYR reaction is characteristic of Streptococcus pyogenes. Streptococcus agalactiae is bacitracin resistant and is identified with the CAMP test, and enterococci are PYR positive but differ in hemolysis and specimen source.