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13 Cards in this Set
- Front
- Back
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Neiserria spp.
Gram ______ Morpohology: ________________ Many non-pathogenic species Commensals of the ______________ in humans Two pathogenic spp. may be transient flora w/o causing disease. N. g___________ and N. ________________ One of two most common causes of bacterial meningitis in U.S. , in healthy hosts, 1 month to 59 yrs old. Remember the other?... ____________________ |
Neiserria spp.
Gram negative diplococci Many non-pathogenic species Commensals of the URT in humans Two pathogenic spp. may be transient flora w/o causing disease. N. gonorrheae and N. meningitidis… One of two most common causes of bacterial meningitis in U.S. , in healthy hosts, 1 month to 59 yrs old. Remember the other?... S. pneumoniae |
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Frequency of bacterial spp. associated with meningitis
< 1 month old: group B streptococci (50%[?]) *** Listeria monocytogenes (25%) S. pneumoniae (5%) 1-23 months: S. ____________ (50%) ********** N. _______ (30%) **** group B strep (15%) Haemophilus influenza b (5%) |
Frequency of bacterial spp. associated with meningitis
< 1 month old: group B streptococci (50%[?]) Listeria monocytogenes (25%) S. pneumoniae (5%) 1-23 months: S. pneumoniae (50%) N. meningitidis (30%) group B strep (15%) Haemophilus influenza b (5%) |
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Freq. –cont.
2-18 years: N. meningitidis (60%) S. pneumoniae (25%) H. influenza b (9%) 19-59 years: S. pneumoniae (60%) N. meningitidis (18%) L. monocytogenes (8%) 60 years up: S. pneumoniae (70%) L. monocytogenes (24%) |
Freq. –cont.
2-18 years: N. meningitidis (60%) S. pneumoniae (25%) H. influenza b (9%) 19-59 years: S. pneumoniae (60%) N. meningitidis (18%) L. monocytogenes (8%) 60 years up: S. pneumoniae (70%) L. monocytogenes (24%) |
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Neiserria spp. –cont.
Non-_____; non-______-forming Aerobic or anaerobic? oxidase ________; “fastidious” Pathogenic Non-pathogenic 22oC - + Agar w/o blood - + + CO2 ___ ___ |
Neiserria spp. –cont.
Non-motile; non-spore-forming Aerobic; oxidase positive; “fastidious” Pathogenic Non-pathogenic 22oC - + Agar w/o blood - + + CO2 + - |
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N. meningitidis Virulence Factors
Polysaccharide capsule Absent on _____coccus Anti-phagocytic __ (#) serogroups Group-specific antibody is protective Group A associated with _______ Groups B, C, and Y most common Antigen present in blood and CSF in severe infections |
N. meningitidis Virulence Factors
Polysaccharide capsule Absent on gonococcus Anti-phagocytic 13 serogroups Group-specific antibody is protective Group A associated with epidemics Groups B, C, and Y most common Antigen present in blood and CSF in severe infections |
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Virulence Factors –cont.
LPS (LOS) Immune evasion: structure mimics host ______lipids found in brain O-side chains integrate host _____ acid to inhibit _______ deposition Outer membrane proteins “___” (Opacity) proteins: may facilitate _____ Sub-divide the serogroups Antibodies to these proteins are bactericidal Pili Adherence to naso___________ epithelium Bind CD46 glycoprotein on host cells |
Virulence Factors –cont.
LPS (LOS) Immune evasion: structure mimics host sphingolipids found in brain O-side chains integrate host sialic acid to inhibit complement deposition Outer membrane proteins “Opa” (Opacity) proteins: may facilitate invasion Sub-divide the serogroups Antibodies to these proteins are bactericidal Pili Adherence to nasopharyngeal epithelium Bind CD46 glycoprotein on host cells |
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Virulence Factors –cont.
Pili and Opa - high level ________ variation Multiple gene copies Pili positioned downstream of different promoters by recombination: “on” (pilE) or “off” (pilS) Pili w altered function; incomplete pili, etc. Opa’s “on” or “off” via translational frame shift in mRNA different combinations of proteins expressed under different conditions. |
Virulence Factors –cont.
Pili and Opa - high level antigenic variation Multiple gene copies Pili positioned downstream of different promoters by recombination: “on” (pilE) or “off” (pilS) Pili w altered function; incomplete pili, etc. Opa’s “on” or “off” via translational frame shift in mRNA different combinations of proteins expressed under different conditions. |
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N. meningitidis Pathogenesis
Pathogenesis different than gonococcus Meningitis (ability to cross blood-brain barrier) toxic septicemia Possesses _____ (#) unique pathogenicity islands in its chromosome “Region _ (#)” required for bacteremia Encodes a _______ receptor and a disulfide oxidoreductase |
N. meningitidis Pathogenesis
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Disease Spectrum
Asymptomatic carrier state 5-__% of population (higher in closed population, ie. military recruits in barracks) Reservoir for disease Carrier state enhances _______ _________cemia (bacteremia) May have _______ manifestations Waterhouse-Friedrichsen syndrome Meningitis - mortality <10% w treatment; 85% w/o Chronic form: associated w complement deficiency |
Disease Spectrum
Asymptomatic carrier state 5-25% of population (higher in closed population, ie. military recruits in barracks) Reservoir for disease Carrier state enhances immunity Meningococcemia (bacteremia) May have cutaneous manifestations Waterhouse-Friedrichsen syndrome Meningitis - mortality <10% w treatment; 85% w/o Chronic form: associated w complement deficiency |
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Waterhouse-Friderichsen syndrome
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Waterhouse-Friderichsen syndrome is failure of the adrenal gland due to bleeding into the gland
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Epidemiology
Spread is human to human Asymptomatic carrier focus of infection Seasonal variation – highest attack rate is late ____, early Spring Age – incidence greatest between 6 months and _ yrs of age. Correlates w decline of ________ antibody and acquired immunity |
Epidemiology
Spread is human to human Asymptomatic carrier focus of infection Seasonal variation – highest attack rate is late Winter, early Spring Age – incidence greatest between 6 months and 3 yrs of age. Correlates w decline of maternal antibody and acquired immunity |
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Lab ID and Treatment
Gram stain is presumptive from CSF or blood Culture on _____ or _______, 37oC + _% CO2 Can use Thayer-_____ if normal flora contam. Latex agglutination for capsule serotype Drug choice? __________ Resistance rare Rifampin, minocycline, sulfonamides used to eliminate pharyngeal carriers |
Lab ID and Treatment
Gram stain is presumptive from CSF or blood Culture on blood or chocolate, 37oC + 5% CO2 Can use Thayer-Martin if normal flora contam. Latex agglutination for capsule serotype Penicillin G drug of choice Resistance rare Rifampin, minocycline, sulfonamides used to eliminate pharyngeal carriers |
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Prevention
Acquired immunity with ___. Exposed by transient colonization w different capsular serogroups. Vaccines available Mixed capsular prep: A,C,Y,W-135 Not very effective for kids under 2 yrs old Serogroup B vaccine in clinical trials Outer membrane vesicles Intranasal administration |
Prevention
Acquired immunity with age. Exposed by transient colonization w different capsular serogroups. Vaccines available Mixed capsular prep: A,C,Y,W-135 Not very effective for kids under 2 yrs old Serogroup B vaccine in clinical trials Outer membrane vesicles Intranasal administration |
