Vibrio sp 1 Characteristics of Vibrio sp 2
Vibrio sp. 1
Characteristics of Vibrio sp. 2 Member of g-proteobacteria Gram negative; curved and straight (pleomorphic) Facultative anaerobe Non-spore-forming Motile Non-descript aw Highly susceptible to killing More resistant to alkaline p. H Generally acid sensitive Environmental reservoir Image from Wikipedia
Species and classification 3 12 species associated with human infection Organism Laborato ry confirme d Under diagnosed % foodborne Cases in US yearly V. cholerae 8 33. 1 100 84 (19 -213) V. vulnificus 111 1. 7 47 96 (60 -139) 142. 4 86 34, 664 (18, 26058, 027) V. 287 parahaemolyticus Other diarrheal: V. mimicus, flavialis, furnissii, hollisae Other wound infection: V. vulnificus, alginolyticus, damsela
4 Commonalities of Vibrios; reservoir Autochthonous flora in estuarine areas Persist independently of human disease (V. cholerae); colonize surface of zooplankton � Chitinase; liberates nutrients Most environmental isolates non-pathogenic Copepod
Control 5 Because of reservoir, difficult to prevent contamination Heating: � Boiling 1 -2 minutes destroys V. cholerae in contaminated shrimp � Low temp pasteurization (50 o. C/10 min) reduces V. vulnificus by 6 log � FDA: Steaming shellfish 4 -9 minutes Frying shellfish for 10 min @ 375 o. C Baking for 10 min @ 450 o. C
Vibrio cholerae 6 Only foodborne (waterborne) illness that is pandemic Over 200 serogroups described Serogroup O 1 Serotypes Ogawa, Inaba, and Hikojima � Classical and El Tor biotypes (hemolysins) � 7 th pandemic (1961 -1975; Indonesia Bangladesh India Soviet Union N. Africa Italy) � Still most predominant world-wide � Serogroup O 139 � 1993 epidemic in Bangladesh and eastern India Non-O 139 Prevalent in estuarine environments � Non- or mildly pathogenic; rarely carry cholera toxin � Vibrio not H-typed
Disease 7 Infectious dose: 1011 straight, as low as 103 with food (what does this suggest? ) Cholera toxin and toxin co-regulated pili (TCP) Several hours to 5 d incubation Acute onset; “rice water” diarrhea Loss of 5 -20 liters of fluid/day Tachycardia, hypotension, vascular collapse “Doughy” skin, sunken eyes, wrinkled hands and feet Treatment: fluid and electrolyte replacement, sometimes antibiotics All Vibrios: liver disease and immunocompromised
Vibrio parahaemolyticus 8 Leading cause of intestinal infections in US due to seafood (raw fish and shellfish) 12 serogroups (O) and 70 polysaccharide (K) types � No correlation between either and disease FDA study: 86% of 635 seafood samples were positive � Mostly low levels (10 CFU/g) but some up to 1000 CFU/g � Mostly unshucked oysters, unshucked clams, unpeeled shrimp, live crabs (all >60% positive)
9 Characteristics of V. parahaemolyticus Does not encode cholera toxin or TCP No single factor associated with ability to cause disease Thermostable direct hemolysin (Kanagawa hemolysin) � 96. 5% of human isolates are positive (KP+) � 1% environmental isolates are KP+ � Toxin is heat stable (30 min 100 o. C); no evidence it is sufficient for disease Prefers warmer waters, intermediate salinity (rare in freshwater)
Foodborne illness and V. para 10 Almost exclusively seafood that is � raw, � inadequately cooked, or; � cooked and re-contaminated Doubling time of � 8 -9 min at 37 o. C � 12 -18 min in many seafoods 4 -30 h incubation, typical disease (diarrhea, abdominal cramps, fever, vomiting) 3 -5 days Infectious dose ~2 x 105 to 3 x 107 � What was bacterial load in most seafoods again? � What does this tell you?
Foodborne illness and changing ecology 11 2011: 8 cases seen in Massachusetts, 2 linked to oysters harvested from state fisheries 1 st time this organism was reported � Why so rare before this? Vibrio management plan Climate change link?
Vibrio vulnificus 12 Most serious of Vibrio diseases Septicemia; 50 -60% fatality rate Also causes wound infection � Associated with contact with seawater/shellfish � 20 -25% fatality rate Infectious dose, ~106 � in animal models of liver necrosis, as low as 1 CFU � Epi studies suggest those with liver cirrhosis secondary to alcoholism and immunocompromised are susceptible
13 2 -25% Na. Cl, optimal about 10 -18%; obligate halophile
Vibrio vulnificus disease 14 Incubation time: 7 h to 10 days Fever, nausea, low blood pressure; GI symptoms less common Secondary lesions on legs � necrotizing fasciitis � vasculitis � sometimes requires amputation As with V. P. , produces many toxins (hemolysin, proteases, DNases, lipases, etc) but none are defining
15 http: //outbreaknewstoday. com/florida-reports-most-vibrio-vulnificus-cases-in-years 24498/
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