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29 Cards in this Set
- Front
- Back
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describe the basic biology of H. influenzae
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gram neg small rods/coccobacilli (look like rice grains on gram stain). oxidase pos, LOS, fastidious, chocolate agar, pili, non siderophore iron uptake, mucosal pathogen, normal flora of some in nasopharynx, X (hemin) and V (NAD) factors for growth, typeable strains have capsule, non typeable do not
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diseases caused by typeable H. influenza? non typeable H. influenza?
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invasive diseases like meningitis, epiglottitis, septicemia, and bacteremia. Non invasive diseases like otitis media (common cause of children's otitis media), sinusitis, bronchitis, and pneumonia
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how does Hi get to the meninges?
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resp tract infection, blood stream or lymoh, to the BBB
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where do you get a sample to culture if the child has epiglottitis?
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from the blood
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what is the structure of the Hib strand capsule and why is it so important?
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polyribosylribitophosphate (PRP) which is what they used for the vaccine
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what pathogens secrete an IgA protease?
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Neisseria, S. pneumoniae, H. influenzae
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how fraction of bronchitis cases is due to H. influenza?
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1/4 just as S. pneumoniae is 1/4 too
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how is H. influenza transmitted?
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via resp. droplets
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what has the Hib vaccine done for the US? other countries?
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20000 cases a year down to 50 in US. Some countries cannot afford vaccine and thus Hib still has 3 mil cases a year and 700K deaths a year worldwide
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who is at risk for H. influenza?
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complement deficiency and splenectomy bc H. influenza is affected mainly by antibodies
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what is diagnostic for H. influenza?
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culture org from suspected infection site except epiglottis and gram stain
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since children from 6mo to 3 yr are not good at making B cell antibodies against carb antigens, how does the Hib vaccine work.
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they conjugate the PRP capsule with tetanus or diphtheria toxoid to increase a T cell response
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if pt has not gotten Hib vaccine, what is the treatment for H. influenza?
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3rd generation cephalosporin bc of penicillin resistance, Rifampin is given as prophylaxis for all contacts
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describe the disease caused by H. ducreyi.
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a chancroid, which is a soft painful ulcer on genitalia, it is an STD
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what disease is caused by H. aegyptius?
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bacterial conjunctavitis
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basic biological properties of bordetella pertusis?
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gram neg rod/coccobacilli, aerobic, non-fermentative, beta hemolytic via adenylate cyclase toxin, oxidase positive, many virulence factors, facultatvie intracellular path
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describe the catarrhal stage of whooping cough.
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colonization pd, 1 wk or so, cold like symptoms, bacteria adhere to ciliated epi in upper resp tract, can culture org pharyngeally, 3 adherance toxins: filamentous hemagglutinin, pertactin and Ptx (pertussis toxin), antibiotics work in this phase
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describe the paroxysmal stage of whooping cough.
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whoop sound cough in 50%, vomitting, hard to find orgs, antibiotics do not work. toxins: tracheal cytotoxin, pertussis toxin, adenylate cyclase toxin
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describe the convalescent phase of whooping cough.
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diminished paroxysmal cough, development of secondary bacterial pneumonia, rare encephalopathy
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when B. pertusis is adhering to ciliated resp. epi cells, what is FHA binding to?
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integrin CR3 on macs and galactose or sulfatide of epi cells
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binding of B pertusis to the upper resp tract ciliary epi cells effects mechanical host immunity how?
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prevents us from coughing crap up like we usually do when stuff gets in our cilia
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how does the pertusis toxin work?
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AB toxin and ADP ribosylator, inhibits Gia, leading to activation of adenylate cyclase and thus increased resp secretions and mucous
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how can B pertusis increase adenylate cyclase?
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via pertusis toxin (see other card) or adenylate cyclase toxin (toxin that is inactivated adenylate cyclase until it goes in the cell and is activated by calcium/calmodulin; it is also a B hemolysin)
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what does B pertusis's tracheal cytoxin do?
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it is a part of the peptidoglycan that is released and kills ciliated epi cells,
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epidemiology of B pertusis?
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#1 bac killer worldwide for which a good vaccine exists, #7 ID killer, humans and primates are reservoirs, mainly hits infants, but adult infection on the rise as well as overall infection...
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how should B pertusis be diagnosed?
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culture in early stage, and verify with PCR, check vaccine history
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what is the antibiotic treatment for B pertusis?
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erythromycin in early stages only
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describe the vaccine for B. pertusis.
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acellular pertusis with pertusis toxin and FHA
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what org is related to H. influenza, has a leukotoxin that likes neutros, causes peridontitis, bite wound infections, and endocarditis? treatment?
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Actinobacillus actinomycetemcomitans, cephalosporins, tetracyclines or fluoroquinolones
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