Haemophilis and Bordatella Flashcards
H. influenzae
G- Coccobacilliary aerosol facultative anaerobe fastidious
H. Influenzae Dx
CULTURE:
Chocolate agar: requires factor V-nicotinamide and factor X-hemin
DIRECT MICROSCOPY:
Meningitis: Spinal tap and pt presentation (fev, irritable, headache, stiff neck)
CAPSULE DETECTION:
Type B agglutination test
H. Influenzae Sx
epiglottitis, inspiratory stridor, drooling, (URT infxn: sinusitis, pneumonia)
“cherry red epiglottitis”
cellulitis
otitis media
meningitis (capsular– type B strain)
sepsis, septic arthritis & bacteremia (in asplenic patients/sickle cell pts bc spleen required to remove encapsulated organisms)
H. influenzae Vaccine
Vaccine for Type B (typeable form)
Polysaccaride capsule conjugated to diptheria protein toxoid
between 2 and 18 month
H. influenzae Tx
B-lactam, cephalosporins, macrolides, fluorouquinolones
Meningitis/systemic:
Ceftriaxone, cefotaxmie
Rifampin used for prophylaxis for family members
Actinobacillus Actinomycetemcomitans
peridontitis, endocarditis, bite wound infection; heart patients must undergo prophylaxis bc of these
grow slow in blood culture
Aggregatibacter aphrophilus
endocarditis; heat pts undergo prophylaxiz bc of these
grow slow in blood culture
Pasturella multocida & canis
cat/dog bite wound
sx: cellulitis & lymphadenitis; chronic respiratory disease, systemic infxn for immunocompromised, *meningitis (rare)
dx: chocolate agar, musty odor w/butteryfly colonies, oxidase +
tx: penicillin
H. parainfluenzae
bacteremia, endocarditis
H. aegyptius
purulent conjunctivitis
H. ducreyi
chancroid (STD-rare in US)
H. influenzae (typeable)
transient colonizers (create issue and then leave)
polysacc. capsule w/PRP (polyribitol phosphate) – Abs against this effective
Type A-F, B most pathogenic
H. influenzae (non-typeable)
URT: sinus and ear issues for children
LRT: pneumonia for COPD pts
throat and mucous membranes (vs transient colonizers)
H. influenzae virulence factors
Polysacc capsule: anti-phagocytic (PRP)
LPS lipid A: meningeal inflammation
IgA1 protease: colonization
Bordetella pertussis
G- coccobacilliary aerosol obligate aerobes fastidious
B. pertussis virulence factors
Adhesins
- filamentous hemagglutinin (FHA): binds tracheal ciliated cells; primary component of acellular pertussis (aP) vaccine
- Fimbriae (FIM): stimulates humoral immunity; in some vaccines
- Pertactin (PRN): similar to FHA
Toxins
-Pertussis toxin: AB toxin, lymphocytosis, primary component of vaccine; (ribosylation and inhibition of Gi, increase in cAMP and disables chemokines prod by lymphocytes and unable to make into BS = massive aggregation in the bloodstream = lymphocytosis)
- Adenylate cyclase (CyaA): anti-inflamm and anti-phagocytic (like EF in anthrax)
- Tracheal cytotoxin: damages cilia of respiratory tract, induced fever IL-1
- LPS: activates alternate complement pathway
Sx/Stages of pertussis
Catarrhal- rhinorrhea, fever, nonspecific cough (greatest communicability)
Paroxysmal- ciliated epithelium must be shed (2wk-2mo)
Convalescent- “100 day cough”; intermittent episodes of cough
(last up to 3 month)
- infant/children disease > adults/adoles
- whoop uncommon in adults
- adults often source of infection
Complications: pneumonia, seizures, encephalopathy, death, hemorrhage
B. pertussis Dx
CXR
normal (see some extra white shit)
Elevated WBC
PCR (BEST)
or NAAT- nasopharyngeal secretions
CULTURE (earlier)
Charcoal, BG, RL media
SEROLOGY
B. pertussis Tx
Erythro, Clarithro, Azithro
Erythromycin for prophylaxis
Supp
B. pertussis Vaccine
DTaP; aP
acellular pertussis; PT, FHA, pertactin, fimbrial protection
