Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Escherichia coliVibrio choleraeCampylobacter spp.Enterics•TWENTY (20) species of Vibrio have been identified•TWELVE (12) of these species are responsible for human disease• V. parahaemolyticus Ingestion of contaminated shellfish • V. vulnificus Fishermen; highly lethal systemic infection• V. cholerae Potentially lethal intestinal infectionVibrio choleraeAn ancient pathogen“In Alexandria, the streets were still with fear: this ‘virus’, …sneaked into healthymen in the morning, doubled them into knots of spasm-racked agony byafternoon, and put them to rest beyond the reach of all pain by night”.-Microbe Hunters, Paul de Kruif (1926)“fok lun” - China, >2000 yrs agoShushruta Samhita - 400bce – 500bce, Sanskrit1600’s - ‘flux du ventre” [flow of the stomach] Goa, France, Brazil, Ghent, Tubingen, LondonJohn Snow - First instance of defining a source ofInfection using Epidemiology (1849)Broad St. Water PumpWater from downstreamon the Thames RiverDeaths, 10 day period in 1849London, EnglandBacterium had NOT been identified !!Flagellum“…no healthy man can ever be attacked by cholera unless he swallows the ‘comma microbe’…it is only in the intestine of man, or in highly polluted water like that of India that is can grow”. - Robert Koch (1882)Bacterium identified in 1882by Robert KochVibrio choleraeEndemic in Asia: >8 million cases annually, 124,000 deaths(Bangladesh, southern India, Vietnam, etc.)Seven pandemics since 1817(Europe and Asia): 1961-present, 1899-1923, 1881-1896 , 1863-1879, 1852-1859, 1829-1849, 1817-1823Entry into the Western Hemisphere Peru, Alabama, Chile 1991-1994Haiti 2010Cholera cotDehydrationVibrio cholerae - Severe diarrheal symptoms> ‘rice water stool’ (mucus)> 5-20 liters water loss/dayVibrio cholerae Gram-negative, motile (flagellated) bacillus“Comma-shaped” bacteriumFree-living (Environmental) & gut (Pathogenic)Facultative anaerobeCapsule (polysaccharide)Pilus (attachment to gut epithelial cells)Glucose, sucrose utilization (fermentation)Oxidase – positiveLPS - Antigenic variants used for serotypingpilusflagellumcapsuleIndia ink stainLPS polysaccharidesSerologically differentiate Vibrio cholerae strains>138 O serotypesMost prevalent virulent strains: O1 and O139Prior to 1993: O1396th, 7th pandemics, Haiti caused by O1 serotypesTCBS Agar(Selective!)-Bile salts (no gram+ )-pH 8.6 (high)-Thiosulfate (sulfur)-Citrate-Sucrose -Bromothymol blueVibrio cholerae -yellow (low pH) (sucrose fermentor)Flagellae MotilityMajor virulence determinants for V. choleraeInfection: ORALFlagellaeMotility is required to swim thru the mucus lining to the gut epithelial cellsToxin-coregulated pilusAttachment of bacterium to gut cellsExpressed only when CT is expressedHA protease (‘detachase’)V. cholerae is shed from the gut in diarrheal fluidsDispersal to other persons Contaminated water, food- 60% mortality w/o treatmentAttachment of V. cholerae: Requires interaction between the bacterium’s pilus and the microvilli (“brush border”) on the gut cell’s surfaceNon –invasive (remains attached to the cell surface)pilusCholera toxinHeat-labile protein (Enterotoxin) secreted into the lumen of the gutBinds to ganglioside GM1 receptor located on surface of gut epithelial cellsCT transported into host cell’s cytoplasmElevates level of intracellular cAMP; stimulates release of K+, Na+) from cell. Cellular water follows the ion gradientSEVERE diarrheal symptomsDeath by electrolytic shockVibriophageLysogenic conversion of avirulent strains of V. cholerae Cholera toxin genes (ctxA ctxB) - encoded on phage genome‘Helical-shaped’ bacteriumTwo polar flagellaeNext,…. Another enteric bacteriumthat elicits diarrheal symptomsCampylobacter spp. A “vibrio-like” bacteriumPromiscuous host range: Major cause of diarrheal disease in animals Cattle, sheep, rodents, poultry, dogs, cats, birdsRecently, implicated in human diseaseReservoirs for Campylobacter spp.Domestic and wild animalsUndercooked meatsUnpasteurized milkcheese from raw milkCampylobacter spp. Gram-negative, helical bacillus (“curved or spiral rod”)Motile (flagellated) (Two!)Encapsulated (polysaccharide) Does not ferment (utilize) sugarsMicroaerophilicRequires C02 for growthSmall organismAndrey V. Karlyshev et al.Campylobacter spp. are exceptionally smallDifficult to observe using optical microscopy. (1600x)Scanning electron microscopy reveals the unique shape of C. jejuni cells.1600xDomestic & wild animals are reservoirs forCampylobacter that cause human diseaseCampylobacter spp. C. jejuni Acute gastroenteritisC. fetus Systemic infection/bacteremia meningitis, and septic fetal abortionsC. coli Proctitis/gastroenteritis septic fetal abortionsVirulence Features for Campylobacter spp.Factors have not been well-defined for: (1) Attachment (2) Motility (3) Invasion Infection by C. jejuni: Mucosal surface of intestine is ulcerated, edematous, bloody, inflammedMonocytes are attracted to the areaRoles for cytopathic toxins, But, enterotoxins & endotoxic activity have not been well-defined***Guillain-Barre Syndrome Autoimmune disease elicited by antigenic cross-reactivity between the capsule polysaccharides and sugar-containing lipids on the surface of neuronal cells; (Sugar structures are very similar!)One pathogen = One type of diseaseSalmonella enterica S. enteritidis GastroenteritisShigella flexneri DysenteryVibrio cholerae Severe diarrheaCampylobacter jejuni Acute GastroenteritisGastroenteritisUrinary tract infections Neonatal meningitis PeritonitisMastitisSepticemiaPneumoniaHemolytic-uremic syndromeWhich microorganism ???Escherichia coliGastroenteritisUrinary tract infections Neonatal meningitis PeritonitisMastitisSepticemiaPneumoniaHemolytic-uremic syndromeLess than 0.1% of the culturable microflora in a healthy gutSymbiotic relationship between ourselves and our gut floraNon-pathogenic E. coli is a normal constituent of our gut