Gram – Joint fluid: neutrophils + gram negative coccobacilli (Haemophilus influenzae)
A simulated joint fluid smear collected from an 8 year old immigrant from Africa was sent to category A, B, C, and C1 laboratories for Gram staining.
Participants were expected to report the presence of gram negative coccobacilli and neutrophils.
MAIN EDUCATIONAL POINTS from GS144-1
- In simulated Gram stain smears such as this joint fluid, H. influenzae will appear predominantly, and typically, as a gram negative coccobacilli or small gram negative bacilli with a fairly uniform morphology.
- In direct smears from patient material it is not unusual for the ap-pearance of H. influenzae to be somewhat pleomorphic and for the organisms to sometimes stain faintly and be difficult to see.