Vibrio Vibrio cholerae -gastroenteritis Vibrio parahaemolyticus -gastroenteritis, wound infection, bacteremia Vibrio vulnificus -wound infection, bacteremia

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Text of Vibrio Vibrio cholerae -gastroenteritis Vibrio parahaemolyticus -gastroenteritis, wound infection,...

  • VibrioVibrio cholerae -gastroenteritisVibrio parahaemolyticus -gastroenteritis, wound infection, bacteremiaVibrio vulnificus -wound infection, bacteremia

  • Vibrio sp.Gram-negative rodsCurves or comma shapedNon-spore forming Highly motile-single polar flagella Associated with salt waterOxidase positiveFacultative anaerobeTolerate alkaline conditions to pH9.0 Readily cultivated, Simple nutritional requirements

  • Vibrio choleraeAntigenic structureCommon heat-labile flagellar H antigenO lipopolysaccharide confers serologic specificityMore than 150 O antigen serogroupsOnly O-1 and 0139 serogroups cause Asiatic choleraThree serotypes; Ogawa, Inaba, HikojimaTwo biovars; classic and El Tor

  • 2 biotypes of serogroup O-1 Classical biotype El Tor biotype. Serogroup 139

  • V. cholerae - Transmissionfood feceswater fresh salt

  • Vibrio choleraeEpidemiologyEpidemic cholera-spread by contaminated water under conditions of poor sanitationEndemic-consumption of raw seafoodCopepods

  • Vibrio choleraePathogenesisIngest 108-1010 organismsNon invasive infection of small intestineOrganisms secrete enterotoxinWatery diarrhea

  • Virulence factors of V.cholerae O1 and O139Virulence factorBiological effectCholera toxinHypersecretic of electrolytes and waterCoregulated pilusAdherence to mucosal cells adhesinAccessory colonization factoradhesinHemagglutination proteaseReleases bacteria from mucosal cellsZona occludens Exotoxin Accessory cholera enterotoxinExotoxin Flagellum Motility Siderophores Iron sequestration

  • Cholera toxinEnterotoxin-cholera toxin-CtxABEncoded by a prophageMolecular mass of 84,000 daltonsA subunit-ADP-ribosylating toxinB subunit-bind GM1-gangliosides on enterocytesA subunit ADP ribosylates Gs-alpha which regulates activation of adenlyate cyclaseResult is persistent increase in cAMP levelsHyper secretion of Na, Cl, K, bicarbonate and H20

  • Vibrio cholerae-Clinical manifestationsAsymptomatic colonization to fatal diarrheaOnset 2-3 days after ingestionAbrupt onset of watery diarrhea and vomitingRice water stoolsSevere fluid and electrolyte loss-dehydration, metabolic acidosis, hypovolemic shock, renal failureDeath 60% if untreated, 1% if treated for fluid loss

  • Pathogenicity of V. cholera Dehydration and death Massive secretion of ions/water into gut lumen

  • ImmunityStrong immunity after recovery, SIgA

  • Bacteriological DiagnosisSpecimens: stool, vomitus.Stained smearCulture: alkaline peptone water of agar plate, and TCBS agar plate.Quick immunological methods: immunofluorescent ball test; PCR.

  • Vibrio-Prevention and ControlImproved sanitationFluid and electrolyte replacement Antibiotic prophylaxisImproved food handling

  • Vibrio parahemolyticusOne kind of halophilic vibrios; optimal NaCl concentration contained in culture media is 3.5%; hemolysin related to its pathogenicity, can be detected by human or rabbit RBC test (Kanagawa test); cause food poisoning in human beings. raw sea-foodClinical manifestationsSelf-limiting diarrhea to mild cholera-like illness24 hours after ingestion-explosive water diarrheaHeadache, abdominal cramps, nausea, vomiting, low grade fever for 72 hours or moreUneventful recoveryWound infections in people exposed to seawater-containing vibrios