Haemophilus

Haemophilus influenzae

Haemophilus parainfluenzae

Identification

Colony morphology: suspected when there is an organism that only grows on the chocolate plate. It may have some small growth or satellitism on the blood agar plate in rare cases or if paired with S. aureus.

1. Gram stain
2. XV test
3. β-lactamase test

Gram Stain

When a gram stain is made from a single, well-isolated colony, it may appear pleiomorphic with both cocci and bacilli forms appearing. However, being from a single colony, all of the organisms present are the same. This is the characteristic coccobacilli appearance.