DISTINCTIVE PROPERTI20

DISTINCTIVE PROPERTI20 - produce cytotoxic substances that...

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DISTINCTIVE PROPERTIES: Neisseria are Gram-negative diplococci with their adjacent sides flattened. These organisms are aerobic, strongly oxidase-positive, have an oxidative metabolism, are susceptible to drying and are fastidious (growth is inhibited by free fatty acids). There are four types of N. gonorrhoeae based on the presence of fimbriae; T1, T2, T3 and T4. N. meningitidis is serotyped by the antigenic character of its capsular polysaccharide; several groups including A, B, C, 29E, W-135 and Y are recognized. PATHOGENESIS: Gonorrhea is a sexually transmitted disease. The sites of infection include the urethra (in men) and the cervix (in women). Fimbriae (pili) are very important for the gonococcus to attach to host cells. N. gonorrhoeae lacking fimbriae are avirulent. A substance called Protein I makes up 66% of the outer membrane protein of N. gonorrhoeae . This protein is antigenic and is used as the basis of some serological tests . N. gonorrhoeae
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Unformatted text preview: produce cytotoxic substances that damage ciliated epithelial cells in fallopian tubes; the LPS endotoxin may be partly responsible. N. gonorrhoeae also produce an extracellular protease that cleaves a proline-threonine bond in immunoglobulin IgA. This causes loss of antibody activity. Approximately 9-15% of affected women contract Pelvic Inflammatory Disease (PID) as a consequence of gonorrhea. This is often a polymicrobic infection involving Bacteroides and other anaerobes. The virulence of N. meningitidis is associated with its antiphagocytic capsule. The meningococcal LPS is as toxic as Escherichia or Salmonella and causes suppression of leukotriene B4 (a chemokinetic/chemotactic factor) synthesis in PMNs. Untreated, meningococcal meningitis has a mortality approaching 85%. N. meningitidis produces proline-threonine and proline-serine proteases, but any particular isolate will only produce one or the other....
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DISTINCTIVE PROPERTI20 - produce cytotoxic substances that...

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