34 Haemophilus Flashcards
Describe the structural morphology of Haemophilus.
- Small G(-), facultative anaerobic rods.
What are the 3 Haemophilus strains that are medically important?
- H. influenzae, H, aegyptius, H. ducreyi
What are the characteristically requirements for Haemophilus to grow? (2)
- Hemin (X factor)
- Nicotinamide adenine dinucleotide (NAD also called V factor for vitamin)
How many antigenic serotypes and how many biotypes of H. influenza are there?
- Serotypes: 6 [ A thru F]
- Biotypes: 8 [I thru VIII]
What is the major virulence factor in H. influenzae type B?
- The antiphagocytic polysaccharide capsule, which contiants ribose, ribito, and phosphate referred to as polyribitol phosphate [PRP].
What is the Immunoglobulin proteases that are produced by both encapsulated and noneencapsulated strains of H. influenza and what does it do?
- IgA1 proteases that facilitate colonization of the organisms on mucosal surfaces by interfering w/ humoral immunity.
What diseases can Haemophilus?
- Meningitis, epliglottittis, cellulitis, arthritis, otitis, sinusitis,and lower respiratory tract, conjunctivitis , chancroid and other opportunistic infections.
How is H. influenzae treated?
- Broad-spectrum cephalosporins for serious infection, less severe infections such as sinusitis and otitis with ampicillin.
Which strain of Haemophilus causes conjunctivitis (pink-eye).
H. aegyptius
Which strain of Haemophilus causes meningitis, epiglottitis, and pneumonia?
- H. Influenzae.
Which strain of Haemophilus causes chancroid?
H. ducreyi
What are the clinical manifestations of H. ducreyi infection?
- 5-7 days after exposure, a tendure papule w/ erythematous base develops on the genitalia or perianal area. Within 2 days the lesion ulcerates and becomes painful and inguinal lymphadenopathy is commonly present.
How is H. ducreyi infection cured?
Erythromycin
