医学微生物学资料：Vibrio cholerae

1、Vibrio, Campylobacter,and Helicobacter Practice of frame work based learning1Features ofVibrio, Campylobacter BACTERIOLOGYPATHOGENESISORGANISMGROWTHUREASEEPIDEMIOLOGYADHERENCETOXINSDISEASEVibriocholeraeFacultativeFecaloral, waterborne, pandemicsSurface proteinb, piliCTcWatery diarrhea (cholera)Campy

2、lobacter jejuniMicroaerophilicAnimals, unpasteurized milkUnknowndUnknowneDysentery, watery diarrheaHelicobacter pyloriMicroaerophilic+Human, gastric secretionsfOMPsgVacAh, urease, CagiChronic gastritis, ulcers, adenocarcinoma, lymphomaaAll are curved Gram-negative rods with similar morphology.bSurfa

3、ce protein able to bind to chitin and human intestine.cCholera toxin.dLipooligosaccharide, flagellin, a major outer membrane protein (MOMP), and a fibronectin-binding protein CadF are candidate adhesions.eCytolethal-distending toxin is a candidate toxin.gOMPs, outer membrane proteins (BabA, SabA, Al

4、pA, AlpB, HopZ).hVacuolating cytotoxin.iNot technically a toxin, but Cag is strongly associated with virulence2Dept.of Medical Microbiology and Parasitology,PUMCVibrio cholerae3Dept.of Medical Microbiology and Parasitology,PUMCFramework based learning Bacteriology Growth and structure Cholera toxin

5、Cholera /clinical aspectsEpidemiology Pathogenesis ImmunityManifestations Diagnosis Treatment Prevention 4Dept.of Medical Microbiology and Parasitology,PUMCVibrios most commonly reside in GROWTH AND STRUCTURE5Dept.of Medical Microbiology and Parasitology,PUMCSensitive to .6Dept.of Medical Microbiolo

6、gy and Parasitology,PUMCVibrio choleraeOxidase-positiveGrowth prefers alkalineCholera is limited to O1 and O139 serotypesBiofilm produced in environment7Dept.of Medical Microbiology and Parasitology,PUMC8Dept.of Medical Microbiology and Parasitology,PUMCV. cholerae genome 2 circular chromosomesChole

7、ra toxin (ctxAB) toxin-coregulated pilus,TCP Accessory colonization factorsRegulatory factors 9Dept.of Medical Microbiology and Parasitology,PUMCCHOLERA TOXINcolonizing factor (toxin-coregulated pilus TCP) 10Dept.of Medical Microbiology and Parasitology,PUMCIntestinal fluids pouring out11Dept.of Med

8、ical Microbiology and Parasitology,PUMCCholera：Clinical aspectsRapidly progressive dehydration and death12Dept.of Medical Microbiology and Parasitology,PUMCEPIDEMIOLOGYSerogroup O1 Serogroup O13913Dept.of Medical Microbiology and Parasitology,PUMC“Cholera seasons ”14Dept.of Medical Microbiology and

9、Parasitology,PUMCABO blood group status15Dept.of Medical Microbiology and Parasitology,PUMCVillages at Ganges16Dept.of Medical Microbiology and Parasitology,PUMCEPIDEMIOLOGY (key points)Transmission is through untreated water supplyIncubation period is 2 daysCholera is endemic in India and AfricaPan

10、demics span decadesGulf Coast cases result from undercooked shellfishLatin American epidemic is widespreadEI Tor biotype dominated 20th centuryNew O139 serotype is spreadingSurvival in shellfish and plankton facilitates epidemics17Dept.of Medical Microbiology and Parasitology,PUMCCholera in Haiti in

11、 201018Dept.of Medical Microbiology and Parasitology,PUMCFecal oral transmission病原菌排出苍蝇等媒介把病原菌带到食物患病病人或带菌者不注意个人卫生病菌污染水源及食物受污染的食物及饮水19Dept.of Medical Microbiology and Parasitology,PUMC Countries reporting imported cases Areas reporting outbreaks World distribution of cholera in 200920Dept.of Medical

12、Microbiology and Parasitology,PUMCSpread of Vibrio cholerae O1 in the Americas, 19911994. (Courtesy of Dr.Robert V. Tauxe, Centers for Disease Control and Prevention, Atlanta; with permission.)21Dept.of Medical Microbiology and Parasitology,PUMC22Dept.of Medical Microbiology and Parasitology,PUMCCho

13、lera in china 23Dept.of Medical Microbiology and Parasitology,PUMC24Dept.of Medical Microbiology and Parasitology,PUMCPATHOGENESISToxin-coregulated pilus (TCP)Large doses required to pass stomach acid barrierPili and proteinsCT-stimulated intestinal hypersecretion causes diarrheaFluid loss Small int

14、estine loses liters of fluidK+and bicarbonate losses cause hypokalemia and acidosisIntestinal mucosa is structurally unaffected; no invasion25Dept.of Medical Microbiology and Parasitology,PUMCToxR controls CT and TCP genesBiofilm formation expressed in environmental crustaceansGenetic Regulation of

15、Virulence26Dept.of Medical Microbiology and Parasitology,PUMCSpread of Vibrio cholerae O139 in the Indian subcontinent and elsewhere in Asia, 1992199427Dept.of Medical Microbiology and Parasitology,PUMCIMMUNITYAttack rate is higher with achlorhydriaImmunity is associated with sIgA28Dept.of Medical M

16、icrobiology and Parasitology,PUMCMANIFESTATIONSAsymptomatic , mild diarrhea, sudden onset of explosive and life-threatening diarrhea (cholera gravis).Extreme watery diarrhea causes large fluid lossDehydration and electrolyte imbalance are the major problemsFever is usually absentClinical symptoms pa

17、rallel volume contraction29Dept.of Medical Microbiology and Parasitology,PUMC30Dept.of Medical Microbiology and Parasitology,PUMCLaboratory dataElevated hematocrit in nonanemic patients;Mild neutrophilic leukocytosis; Elevated blood urea nitrogen and creatinineNormal sodium, potassium, and chloride

18、levels; Markedly reduced bicarbonate level (15 mmol/L); Elevated anion gap Arterial pH is usually low (7.2).31Dept.of Medical Microbiology and Parasitology,PUMCDIAGNOSISStool culture using selective media is required32Dept.of Medical Microbiology and Parasitology,PUMCThiosulfate Citrate Bile Salts S

19、ucrose Agar（TCBS琼脂 ）33Dept.of Medical Microbiology and Parasitology,PUMCTREATMENTOral or intravenous fluid and electrolyte replacement is crucialAntimicrobial therapy can reduce duration and severity34Dept.of Medical Microbiology and Parasitology,PUMCAssessing the degree of dehydration in patients w

20、ith cholera 35Dept.of Medical Microbiology and Parasitology,PUMCOral rehydration solution (ORS) 36Dept.of Medical Microbiology and Parasitology,PUMC37Dept.of Medical Microbiology and Parasitology,PUMCPREVENTIONWater sanitation and cooking shellfish prevent infectionSanitary disposal of fecesVaccines are disappointing38Dept.of Medical Microbiology and Parasitology,PUMCAcidification of water 39Dept.of Medical Microbiology and Parasitology,PUMCOther VibriosV vulnificussepsis and wound infections linked to raw oysters and iron ove