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29 Cards in this Set
- Front
- Back
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Describe the gram status of haemophilus
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Gram negative coccobacilli
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What are the major types of haemophilus?
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H. influenza, H. parainfluenza, H aegyptius, H. ducreyi
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Where is haemophilus found as normal flora?
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In the oral cavity and upper respiratory tract (particularly children)
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Which species of haemophilus is a HACEK organism?
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H. parainfluenza
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What is the gram status of moraxella catarrhalis?
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It is a gram negative diplococci or coccobacilli
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What bacteria has disease syndromes similar to haeomphilus influenza and what are the diseases?
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Moraxalla catarrhalis- third most commmon cause of otitis media and a common cause of chronic bronchitis; considered a "twin" to haemophilus
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What factors are required for the growth of haemophilus?
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It requires special media with "X" (hemin) and "V" (NAD) factors on an enriched chocolate agar; they do not grow on blood agar and require CO2!
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What are the major virulence factors for haemophilus influenza?
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The capsule is the most virulent factor (antiphagocytic) and contains 6 serotypes, with type b being the most virulent; it also contains LPS endotoxin
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Which serotype of capsule is required for virulence of haemophilus infleunza?
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Type b
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Describe the virulence of non-encapsulated haemophilus
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They are not invasive but they can still cause disease (called nontypeable strains)
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What exo-enzymes does haemophilus contain?
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IgA proteases and beta lactamase (25%)
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Where are non-typeable strains of haemophilus found?
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They are common as normal flora of the nasopharynx of most children and some adults
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Describe the transmission of haemophilus
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Transmission is person to person via inhilation of airborne droplets and shared secretions and mostly from our own normal flora
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Before vaccination, haemophilus was the most common cause of what sort of bacterial infection? What strain of haemophilus was responsible?
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Type b strain of H. influenza was the most common cause of bacterial meningitis in children before vaccination
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What can unencapsulated strains of H. influenza cause in children?
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Otitis media
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What sort of infections are caused by nontypable strains of haemophilus?
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(1) otitis media (2) sinusitis (3) conjuctivitis (H aegyptius) (4) chronic bronchitis, pneumonia (debilitated adults)
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What are the top three causes of otitis media in order?
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(1) streptococcus pneumonia (2) haemophilus infleunza (3) moraxella catarrhalis
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What are the invasive local infections caused by H influenza type b strain?
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epiglottitis, cellulitis, and pneumonia
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What are the invasive infections caused by haemophilus influenza type b strain?
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(1) septicemia with DIC and shock (2) Meningitis
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What is the name of the vaccine given for haemophilus influenza and when is it given?
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It is called the Hib vaccine and it is given on a 4 dose schedule at 2,4,6 ans 12-15 mo
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Describe the vaccine for haemophilus influenza
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It is purified type b capsular polysaccharide conjugated to a protein
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What are unique properties that characterizes mycoplasmas?
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(1)They lack a cell wall (2) pleomorphic in shape (3) cell membrane contains cholesterol (4) slow growth "fried egg" colonies
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Describe how mycoplasma adhere to respiratory epithelium
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They adhere to respiratory epithelium through a protein called P1
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Describe the transmission of mycoplasma
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Transmission is person to person via respiratory secretions
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Describe the habitat of mycoplasma
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They are found in the urinary tract in abscence of disease but they are NOT considered to be normal flora
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In whom do we see infections with mycoplasma?
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School-aged children and young adults; considered to be community aquired and not nosocomial
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Describe the disease syndromes caused by mycoplasma
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pharyngitis, tracheobronchitis (70%) ear pain (myringitis), mild pneumonia (atypical bronchopneumonia!), and inflammation on mucosal surfaces
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Describe the onset of a mycoplasma infection
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The onset is gradual with 2-3 weeks of pharyngitis, chills, fever, ect. a
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What is the most useful diagnostic test in mycoplasma infection?
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Serology examination revealing cold agglutinins (IgM autoantibodies)
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