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21 Cards in this Set
- Front
- Back
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gonococci
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Neisseria gonorrhoeae.
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meningococci
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Neisseria meningitidis.
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chocolate agar
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blood agar heated until the blood becomes brown or chocolate in color, used especially to isolate Haemophilus or Neisseria and other species for which unheated blood is inhibitory.
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Thayer-Martin medium
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5% heat-hemolyzed sheep blood and antibiotics, used for transport and primary isolation of Neisseria
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oxidase test
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a test for the presence of intracellular cytochrome oxidase based on the reaction with p-phenylenediamine; aids in the identification of Neisseria species
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phase variation
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Involves turning on and off production of pili and certain outer membrane proteins.
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antigenic variation
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switch from one pilus antigenic type to another
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Disseminated infection
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infection widely scattered throughout an organ, tissue, or the body.
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NEISSERIA
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gram negative, diplococci, kidney bean shapes face each other
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Neisseria Meningitis- Resevior
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1) Nasopharynx of humans only. Immunity can develop to particular strains
-strict human parasite 2) Spread by respiratory transmition |
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Neisseria Meningitis- Morpholoyg & Metabolism
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1) Kidney bean shaped w/ concave sides facing each other, forming a doughnut
2) Gram - diplococci 3) facultative-anaerobe 4) grows best in high CO2 enviornment 5) Ferments maltose and glucose |
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Neisseria Meningitis- Virulence
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1) Capsule:
a. 9 serotypes b. serotypes A, B, C are associated with epidemics (usually B 2. IgA1 protease 3. Can extract iorn from transferrin via a non0energy requiring mechanism 4. Pili: for adherece |
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Neisseria Meningitis- Toxins
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1) Endotoxin: Lipopolysaccaride (LPS)
2) No exotoxins |
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significance of Neisseria as human pathogens
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-Gram-negative diplococci (really only important gram negative )
-Positive in the oxidase test -capnophilic -cultured on special medium called chocolate agar -Gram-stained, and will show numerous polymorphonuclear leukocytes (PMN's or "polys" or neutrophils -Obligate aerobes catalase positive |
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Neisseria Meningitidis- Clinical
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1. Asymptomatic carriage in the nasopharynx
2. Meningitis: A. Fever B. Stiff neck C. Vomiting D. Lethargy or altered mental status E. Petechial rash 3. Septicemia (meningococcemia): A. Fever B. Petechial rash C. Hypotension Fulminant meningococcemia-bilateral hemorrhage of adrenal glands along w/ hypotension and the petechial rash |
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Neisseria Meningitidis- Diagnostics
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1) Gram shows shows numerous polys
2) Cultured A. on chocolate Agar B. Selective media: prevents growth of othe bacteria (Thayer Martin VCN) C. colonies are obtained and undergo oxidase test for cytochrome C D. gramstain for dipococci gram - E. Fermented in glucose & maltose to determine meningococii or gnonococci |
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Neisseria gonorrhoeae- Reservoir
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1) Humans only ( no immunity to repeated infections)
2) Sexually transmitted |
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Neisseria gonorrhoeae- Morphology and Metabolism
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1) Kidney bean shaped w/ concave sides facing each other, forming a doughnut
2) Gram - diplococci 3) facultative-anaerobe 4) grows best in high CO2 enviornment 5) Ferments only glucose |
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Neisseria gonorrhoeae- Virulence
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1) Pili:
A. Adherence to epithelial cells B. Antigenic variation C. Antiphagocytic: binds bacteria tightly to host cell, protecting it from phagocytosis 2. IgA1 protease 3. Outer membrane proteins: -Protein I: porin -Protein II (opacity protein): presence associated with dark, opaque colonies for adherance |
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Neisseria gonorrhoeae- TOXINS
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1) Endotoxin: Lipopolysaccaride (LPS)
2) No exotoxins |
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Neisseria gonorrhoeae- Diagnostic
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1) Gram stain of urethral pus reveals the iny gram negative donut shaped diplococci within white blood cells
2. Culture A. Culture specimen on chocolate agar B. Selective media: prevents growth of other bacteria * Thayer Martin VCN |
