Overview and Objectives
Main Topic
Subtopic 1:
Beta-hemolytic Streptococci
1.1, 1.2, 1.3
  Subtopic 1 Summary
Subtopic 2: Alpha-hemolytic streptococci
  Activity 2
  Subtopic 2 Summary
Subtopic 3: Gamma Streptococci
3.1, 3.2
  Subtopic 3 Summary
Module Summary

Module Developer

User Evaluation Form

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.

Case Study Discussion

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?