The microbiology laboratory receives a genital culture from a 28-year-old female. The specimen direct Gram stain reveals, gram-positive cocci in clusters and gram-negative cocci in chains. The microbiologist inoculates a sheep blood agar plate, a chocolate agar plate, a modified thayer martin plate and a LIM Broth (selective enrichment for group B streptococci). The second shift microbiologist

Question

identifies the discrepancy and must take corrective action. The discrepancy indi-cates:

a. there is no discrepancy noted.
b. the preliminary Gram stain was erro-neously reported.
c. the microbiologist should cancel this order and reorder a genital screen for group B streptococci.
d. the microbiologist should report out the results from the cultures when growth is evident.

Answer 1

B
The Gram stain as reported indicates gram-negative cocci in chains. Although this gram charac-teristic and pattern may be visible on the direct Gram stain, the microbiologist should note that the morphotype described is most likely group B streptococci that are dying therefore resulting in a poor Gram stain reaction. The skilled microbiologist will recognize this variation in staining and correctly report the organisms as gram-positive cocci in chains based on the correlation with the specimen and potential organisms present in the sample.