Subtopic 2 Summary
An alpha-hemolytic streptococci that is optochin susceptible or bile soluble can be identified as Streptococcus pneumoniae. Other alpha-hemolytic streptococci that are negative for these two tests are grouped as viridans streptococci. Alpha-hemolytic streptococci are those with greenish discoloration in the medium surrounding the colony.
Gram-positive diplococci are observed in the gram stain of a sputum sample of a 60-year-old woman. Numerous neutrophils are observed. Sparse growth on blood agar at 24 hours reveals small colonies with a wide zone of alpha-hemolysis. What tests should be performed? What organism would you suspect?