Haemophilus
-Tiny, Gram-Negative, pleomorphic rods
-Fastidious, sensitive to drying, temperature extremes & disinfectants
-None can grow on blood agar w/o special techniques (chocolate agar)
Require hemin, NAD or NADP for metabolism
-Some are normal flora of the upper respiratory tract/vagina
-Others are virulent species responsible for conjunctivities, childhood meningitis & chancroid
-
H. Ducreyi
-Causes chancroid/soft chancre, an STD
H. Influenzae
-Causes acute bacterial meningitis, epiglottitis, otitis media, sinusitis, pneumonia & bronchitis
-Subunit vaccine Hib available
H. Parainfluenzae & H. Aphrophilus
Normal oral & nasopharyngeal flora, but can also be agents of infective endocarditis