Haemophilus Clinical Microbiology Review 194
ORGANISM PATHOGENICITY GRAM STAIN CULTURE OTHER
H. influenzae
H. influenzaebiotype
aegyptius& H. aegyptius
H. parainfluenzae,
H. haemolyticus, &
H. parahaemolyticus
H. ducreyi
Should be serotyped.
Characteristics are
similar to H. influenzae.
Difficult to differentiate.
Can ID by PCR.
Normal flora of upper respi-
ratory tract. Causes sinusitis,
otitis media, pneumonia,
bronchitis, often in elderly or
compromised. Type b com-
mon cause of pneumonia &
meningitis in children where
Hib vaccine not available.
Both cause conjunctivitis
(pink eye). H. influenzaebio-
type aegyptiusalso causes
Brazilian purpuric fever.
Normal flora of upper respi-
ratory tract. Low incidence of
pathogenicity.
Never normal flora.
Causes chancroid (sexually
transmitted disease).
Small, pleomorphic
GNCB to long fila-
ments. Capsules
may be seen.
Same as above.
Small, pleomorphic
GNCB to long fila-
ments.
Small GNCB, bipolar
staining. May resem-
ble schools of fish or
railroad tracks.
Grows on CHOC in 5%–10%
CO 2. Translucent, moist,
tannish colonies. Encapsu-
lated strains form larger &
more mucoid colonies.
Mousy or bleach-like odor.
May demonstrate satel-
litism with staph on SBA.
Same as above.
Colonies are larger, dry,
& tannish.
Difficult to culture.
