Bordetella And Haemophilus Flashcards
Bordetella pertusis gram stain
Gram negative
Bordetella pertusis oxygen requirements
Strict aero be
Bordetella pertusis cell morphology
Small coccobacillus- singly or in pairs.
Bordetella pertusis hemolysis
Small, transparent hemolytic colonies on a border-gengou medium
Bordetella pertusis transmission
Sticktly human pathogen, transmission by aerosolized droplets (>1m) nonmotile and does not ferment carbohydrates (or grown on common lab media)
Bordetella parapertusis morphology
Grows on regular agar/ lab media. Positive results on sheep blood agar, and MacConkey agar
Bordetella pertusis pathogenesis
7-10 day colonization period with no-symptoms,
Then start symptoms after a week or two: toxin mediated disease
Inflammation interferes with pulmonary secretion clearance
Cough progresses from mild at first, to severe, and slowly resolves
“100-day cough”
Bordetella pertusis 6 toxins
- Pertussigen
- Pertussis toxin
- Adenylate cyclase toxin
- Dermonecrotic toxin (lethal toxin)
- Tracheal cytotoxin
- Endotoxin
Bordetella pertusis pertussigen toxin
Adhesion
Bordetella pertusis Pertussis toxin
Impairs immune response
Bordetella pertusis Adenylate Cyclase toxin
Causes an increase in cAMP production
Bordetella pertusis Dermonecrotic toxin
Lethal toxin- inflammation and cell death
Bordetella pertusis tracheal cytotoxin
Prevents ciliated epithelial cells from beating, which is the irritation causing cough. Also pyrogenic
Bordetella pertusis diagnosis
Based on symptoms, Culture of respiratory secretions on bordet-gengou medium Direct fluorescent antibody testing PCR Slide agglutination
Bordetella pertusis treatment
Erythromycin
Vaccine (part of DTP vaccine- but induced immunity wanes after 5-10 years. Need a booster!)
Haemophilus morphology
Small, gram negative, nonmotile
Haemophilus transmission
Transmitted via respiratory droplets, fomite/ direct contact with contaminated secretions
Part of normal human flora in respiratory tract and oral cavity
3 Haemophilus pathogenic species
Haemophilus influenzae (type b important human pathogen) Haemophilus ducreyi (sexually transmitted) Haemophilus parainfluenzae (opportunistic pathogen- part of normal flora)
Haemophilus influenzae hemolysis and growth
Requires isoVitaleX-enriched chocolate agar
Requires hemin and NADH for growth, which comes from lysis of red blood cells. 5% CO2 enhances growth
Haemophilus influenzae hemolysis and growth factor
No hemolysis zone, both X(hemin) and V(NADH) growth factor
Haemophilus ducreyi hemolysis pattern
No hemolysis zone, requires only X (hemin) growth factor
Haemophilus parainfluenzae hemolysis and growth factor
Alpha or beta hemolysis, and only V (NADH) growth factor
Haemophilus influenzae serotyping/ lab diagnosis
Typing based on polysaccharide capsule PRP capsule (polyribose-ribitol phosphate) in type b 95% of invasive diseases caused by type b (but rate has fallen with vaccine)
Haemophilus influenzae associated diseases
- Meningitis (most serous, can be spread from person to person)
- Epiglottitis- cellulitis and swelling of supraglottic tissues. Rapid airway obstruction (2-4 years old)
- Cellulitis: reddish-blue patches on cheeks or eye area
Haemophilus influenzae pathogenic mechanisms
Anti phagocytic polysaccharide capsule (major)
Lipid A component as a toxin (no exotoxins)
All virulent strains produce neuraminidase and IgA protease
NO EXOTOXINS
Haemophilus influenzae treatment and prevention
His conjugate vaccine for prevention
Haemophilus ducreyi chanchroid
Rare- sexually transmitted disease as soft red papule. Quickly becomes pustular, ulcerated, and painful. Located on the penis in males and either vulva, vagina or cervix in females.
May cause spontaneous rupture of lymph nodes and pus drainage if infection gets bad enough
