3/13/2016 Learning Objectives Food 1.Use basic biochemical characteristics to identify Vibrio 2.Understand what conditions in foods favor Vibrio growth Chapter 17 AN INTRODUCTION 3.Recognize,from symptoms and time of onset,a case of foodborne illness caused bybro Vibrio species 4.Choose appropriate interventions(heat, preservatives,and formulations)to prevent the growth of Vibrio 5.Identify sources of the organism 6.Understand the role of Vibrio toxins and virulence factors in causing foodborne illness Outbreak Vibrios multiply rapidly Seafood Aficionados:"The only Low levels of V parahaemolyticus can way to eat certain seafood is raw" rapidly increase to an infectious level if 2006 and contaminated shellfish shellfish are not refrigerated rapidly after harvest ‘ia-8 e Proper storage temperatures must also Consumed contaminated be maintained during transport, shellfish processing,and storage Self-limiting illness with diarrhea,vomiting,and chills for 1-3 days 义
3/13/2016 1 Chapter 17 Vibrio species Learning Objectives 1. Use basic biochemical characteristics to identify Vibrio 2. Understand what conditions in foods favor Vibrio growth 3. Recognize, from symptoms and time of onset, a case of foodborne illness caused by Vibrio 4. Choose appropriate interventions (heat, preservatives, and formulations) to prevent the growth of Vibrio 5. Identify sources of the organism 6. Understand the role of Vibrio toxins and virulence factors in causing foodborne illness Outbreak Seafood Aficionados: “The only way to eat certain seafood is raw” 2006 and contaminated shellfish • 177 persons became ill with Vibrio parahaemolyticus • Consumed contaminated sh llfi h h ellfi s h • Self-limiting illness with diarrhea, vomiting, and chills for 1-3 days • Vibrios multiply rapidly • Low levels of V. parahaemolyticus can rapidly increase to an infectious level if shellfish are not refrigerated rapidly after harvest • Proper storage temperatures must also be maintained during transport, processing, d an storage
3/13/2016 Levels of total vibrios during 10 days of Raw oysters are consumed for storage at5°c,10°c,and20°c their taste old wives'tale-they act as an aphrodisiac 8 oysters contain hormone-inducing amino acids People rarely consider the hazards associated with eating raw oysters 10 Stoaage Time (days) +5PC量1护C2PC Outbreak Vibrios July-August,1997 .209 persons became ill with gastroenteritis after eating raw oysters Over 20 Vibrio species are described dmrcpsu. 12 cause disease in humans 8 are directly associated with food Culture confirmed V.parahaemolyticus Seafood consumption is strongly outbreak correlated with vibrio infections -<200 CFU per gram of oyster meat illness may occur at bacterial levels lower Vibrios are the dominate species in the than the current action level estuarine waters and are associated US and Canada permit the sale of oysters with with a variety of seafood <10 CFU per gram of oyster meat
3/13/2016 2 Levels of total vibrios during 10 days of storage at 5°C, 10°C, and 20°C • Raw oysters are consumed for - their taste - old wives’ tale - they act as an aphrodisiac - oysters contain hormone-inducing amino acids • People rarely consider the hazards associated with eating raw oysters Outbreak July - August, 1997 • 209 persons became ill with gastroenteritis after eating raw oysters • Symptoms: diarrhea, abdominal cramps, nausea, and vomiting • Culture confirmed V. parahaemolyticus outbreak - < 200 CFU per gram of oyster meat - illness may occur at bacterial levels lower than the current action level • US and Canada permit the sale of oysters with < 104 CFU per gram of oyster meat Vibrios • Over 20 Vibrio species are described • 12 cause disease in humans • 8 are directly associated with food • Seafood consumption is strongly correlated with vibrio infections • Vib i h d i i i h Vib rios are t h e dominate species i n t h e estuarine waters and are associated with a variety of seafood
3/13/2016 Changes in incidence of laboratory-confirmed Vibrios bacterial infections,U.S.,2010* Pathogen Decrease Increase 40%-60%of finfish and shellfish at Yersinia- -52% supermarkets may contain Vibrio species Vibrio 115用 V.parahaemolyticus and V.alginolyticus STEC50157一44%1 are the most commonly isolated Shigella—57%:■ Vibrios are associated with shellfish Salmonella ●3%1 during the summer months Listeria 38以1 Annual incidence increased 78%from the Campylobacter27% baseline endemic level during 1998-2006 -10080-604020020406080100 change compared Relative rates of laboratory-confirmed infections compared with1996-1998re Characteristics of Vibrios by year ce Network United States,1996-2012 ·Many enrichment broths for vibrios STEC015 have been developed ·Alkaline peptone water is most commonly used ·Coupled with growth on TCBS media thiosulfate-citrate- Vibrio cholerae (yellow)and Vibrio parahaemolyticus bile salts-sucrose (dark green on TCBS agar 2010 2012 agar
3/13/2016 3 Vibrios • 40% - 60% of finfish and shellfish at supermarkets may contain Vibrio species • V. parahaemolyticus and V. alginolyticus are the most commonly isolated • Vibrios are associated with shellfish during the summer months • Annual incidence increased 78% from the baseline endemic level during 1998-2006 Relative rates of laboratory-confirmed infections compared with 1996–1998 rates, by year —Surveillance Network, United States, 1996–2012 Characteristics of Vibrios • Many enrichment broths for vibrios have been developed • Alkaline peptone water is most commonly used • Coup g led with growth on TCBS media thiosulfate-citratebile salts-sucrose agar Vibrio cholerae (yellow) and Vibrio parahaemolyticus (dark green ) on TCBS agar
3/13/2016 Characteristics of Vibrios Epidemiology Oxidase test is used to differentiate sucrose Number of vibrios,particularly V.vulnificus positive Vibrio from Enterobacteriaceae and V.parahaemolyticus in surface waters Vibrios are oxidase positive or contain and shellfish correlate with seasonality cytochrome c Fig.2-Relationship betw erature and IFCO Characteristics of Disease Symptoms of the two most common Vibrio species differ Variation in the severities of Vibrio- associated diseases V.vulnificus illness Outcome depends on the person's underlying fever,chills,and nausea health Liver disease no diarrhea -Diabetes mortality:40%-60%of cases -GI disorders V.parahaemolyticus illness -Immune disorders diarrhea,abdominal cramps,nausea, -Long term steroid use Exceptions are V.cholerae O1 and 0139 as vomiting these bacteria infect non-compromised mortality:low people as well
3/13/2016 4 Characteristics of Vibrios • Oxidase test is used to differentiate sucrose positive Vibrio from Enterobacteriaceae - Vibrios are oxidase positive or contain cytochrome c tetramethyl-pphenylenediamine dihydrochloride Epidemiology • Number of vibrios, particularly V. vulnificus and V. parahaemolyticus in surface waters and shellfish correlate with seasonality Characteristics of Disease • Variation in the severities of Vibrio – associated diseases • Outcome depends on the person Outcome depends on the person s underlying ’s underlying health - Liver disease - Diabetes - GI disorders - Immun sor rs e disorders - Long term steroid use • Exceptions are V. cholerae O1 and O139 as these bacteria infect non-compromised people as well • Symptoms of the two most common Vibrio species differ V. vulnificus illness - fever chills and nausea fever, chills, and nausea - no diarrhea - mortality: 40% - 60% of cases V. parahaemolyticus illness - diarrhea abdominal cramps nausea diarrhea, abdominal cramps, nausea, vomiting - mortality: low
3/13/2016 Characteristics of Disease Vibrio vulnificus kills Sarasota man after swimming in Gulf-2014 Vibrios are part of the normal estuarine microflora -Shellfish sanitation programs are not useful in controlling Vibrio infections Essential that raw seafood be kept cold to prevent bacterial growth Essential that it be cooked properly before consumption VELOPING STORY 590 Susceptibility to Physical and Susceptibility to Physical and Chemical Treatments Chemical Treatments Very little is known about the effects of High hydrostatic pressure reduces the preservation techniques and inactivation of number of Vibrios with the additional vibrios advantage that it perfectly shucks oysters Sensitive to cold temperatures Various dried spices,herbs,tomato sauce, Seafood can be protected at refrigeration and organic acids exhibit bactericidal temperatures activities Thermal processing is effective at reducing Depuration of filter-feeding bivalves the number of Vibrios in food (pumping bacteria free water through the USDA recommends an internal temperature tissues)removes Salmone/la and E coli but of 60oc for several minutes to cook shellfish not Vibrio
3/13/2016 5 Characteristics of Disease • Vibrios are part of the normal estuarine microflora - Shellfish sanitation programs are not useful in controlling Vibrio infections - Essential that raw seafood be kept cold to prevent bacterial growth - Essential that it be cooked properly before consumption Vibrio vulnificus kills Sarasota man after swimming in Gulf - 2014 Susceptibility to Physical and Chemical Treatments • Very little is known about the effects of preservation techniques and inactivation of vibrios • Sensitive to cold temperatures • Seafood can be protected at refrigeration temperatures • Th l i i ff ti t d i Thermal processing is effective at reducing the number of Vibrios in food • USDA recommends an internal temperature of 60OC for several minutes to cook shellfish Susceptibility to Physical and Chemical Treatments • High hydrostatic pressure reduces the number of Vibrios with the additional advantage that it perfectly shucks oysters • Various dried spices, herbs, tomato sauce, and organic acids exhibit bactericidal activities • Depuration of filter-feeding bivalves (pumping bacteria free water through the tissues) removes Salmonella and E. coli but not Vibrio
3/13/2016 Vibrio cholerae Vibrio cholerae ·V.cholerae O1 Species distinctions are made based on -one of few foodborne illnesses with -presence of the cholera enterotoxin epidemic and pandemic potential -serogroup Epidemic:many people in one area -potential for epidemic spread become sick at the same time Cholera toxin producing strains are Pandemic:worldwide epidemic associated with epidemic and pandemic cholera 200 serogroups based on LPS-O antigen Vibrio cholerae Vibrio cholerae isolation and identification reservoirs Isolates cultured on biochemical media Normal bacterial flora of estuarine areas used to identify Enterobacteriaceae and Non-O1 and non-0139 are most commonly Vibrionaceae isolated from the environment than O1 or DNA probes are used to identify toxin- 0139 isolates even in epidemic regions producing strains Periodic introduction of O1 isolated into ctx genes shellfish that is consumed raw or Restriction fragment polymorphism undercooked is the cause for local analysis used in epidemiological analysis outbreaks of cholera on the US Gulf Coast and in Australia 6
3/13/2016 6 Vibrio cholerae • V. cholerae O1 - one of few foodborne illnesses with epidemic and pandemic potential - Epidemic: many people in one area become sick at the same time - Pandemic: worldwide epidemic Vibrio cholerae • Species distinctions are made based on - presence of the cholera enterotoxin - serogroup - potential for epidemic spread • Cholera toxin producing strains are associ d i h id i d d i iated with epidemic and pandemic cholera • 200 serogroups based on LPS - O antigen Vibrio cholerae isolation and identification • Isolates cultured on biochemical media used to identify Enterobacteriaceae and Vibrionaceae • DNA probes are used to identify toxinproducing strains - ctx genes • Restriction fragment polymorphism analysis used in epidemiological analysis Vibrio cholerae reservoirs • Normal bacterial flora of estuarine areas • Non-O1 and non-O139 are most commonly isolated from the environment than O1 or O139 isolates even in epidemic regions • Periodic introduction of O1 isolated into shellfish that is consumed raw or undercooked is the cause for local outbreaks of cholera on the US Gulf Coast and in Australia
3/13/2016 CHOLERA.Number of roported es-Unitod States and U.S..2006 Vibrio cholerae reservoirs Persistence of V.cholerae in the environment is facilitated by its ability to assume the viable but nonculturable state VBNC forms cannot be cultured on media but can cause disease Long-term carriage of V.cholerae is rare and not important in the transmission of the disease Patients not treated with antibiotics may shed the bacterium for 2 weeks after illness Asymptomatic carriers occur in household members of persons with acute illness Modes of Vibrio cholerae transmission Vibrio cholerae foodborne outbreaks Water plays a critical role in the transmission of cholera .1854,John Snow a London physician and epidemiologist determined the illness was associated with drinking water from the Thames River at a point below major sewage inflows >
3/13/2016 7 Vibrio cholerae reservoirs • Persistence of V. cholerae in the environment is facilitated by its ability to assume the viable but nonculturable state • VBNC forms cannot be cultured on media but can cause disease • Long-term carriage of V. cholerae is rare and not important in the transmission of the disease • Patients not treated with antibiotics may shed the bacterium for 2 weeks after illness • Asymptomatic carriers occur in household members of persons with acute illness Modes of Vibrio cholerae transmission Vibrio cholerae foodborne outbreaks • Water plays a critical role in the transmission of cholera • 1854, John Snow a London physician and epm g m idemiologist determined the illness was associated with drinking water from the Thames River at a point below major sewage inflows Map of Cholera outbreaks help identify contaminated pump
3/13/2016 Vibrio cholerae Map of foodborne outbreaks Cholera Foods implicated in cholera include outbreaks help identify crabs clams contaminated shrimp frozen coconut milk pump raw fish raw pork mussels millet gruel cockles cooked rice squid street vendor foods oyster raw vegetables and fruits Vibrio cholerae Vibrio cholerae foodborne outbreaks characteristics of the disease One shared characteristics of the foods Explosive,dehydrating diarrhea occurs in is their neutral pH persons infected with CT-producing Foods with an acid pH can be eliminated cholerae from outbreak investigations Many infections are mild or asymptomatic Crabs,shrimp and oysters are implicated Incubation period ranges from several most frequently hours upto 5 days Dependent on inoculum size
3/13/2016 8 Map of Cholera outbreaks help identify contaminated pump Vibrio cholerae foodborne outbreaks • Foods implicated in cholera include crabs clams shrimp frozen coconut milk raw fish raw pork mussels millet gruel cockles cooked rice squid street vendor foods oyster raw vegetables and fruits Vibrio cholerae foodborne outbreaks • One shared characteristics of the foods is their neutral pH • Foods with an acid pH can be eliminated from outbreak investigations • Crabs,py p shrimp and oysters are implicated most frequently Vibrio cholerae characteristics of the disease • Explosive, dehydrating diarrhea occurs in persons infected with CT-producing V. cholerae • Many infections are mild or asymptomatic • Incubation p g eriod ranges from several hours upto 5 days • Dependent on inoculum size
3/13/2016 Vibrio cholerae How cholera affects the body characteristics of the disease Initial symptoms:Loss of appetite, abdominal pain,simple diarrhea Progressive symptoms:rice water stools due to mucus Dose:1011 CFU ml of saline required to cause diarrhea in healthy volunteers 2 Dose:106 CFU gram of food required to cause diarrhea in healthy volunteers Food acts as a buffer Vibrio cholerae ADPR virulence mechanisms OFF GDP Gsa (permanently ON) Infection with V cholerae O1/0139 begins with ingestion of contaminated continued activation food or water Aof adenylate cyclase Colonization of the intestines follows cholera toxin (with help from activator) Cholera toxin is produced Severe diarrhea occurs with excessive decreased Nat absorption by villus cells [cAMP] loss of water and electrolytes increased Cr secretion by crypt cells DRAMATIC WATER LOSS through lumen of gut 9
3/13/2016 9 Vibrio cholerae characteristics of the disease • Initial symptoms: Loss of appetite, abd i l i i l di h bdominal pain, simple diarrhea • Progressive symptoms: rice water stools due to mucus • Dose: 1011 CFU / ml of saline required to cause di h i h lth l t diarrhea in healthy volunteers • Dose: 106 CFU / gram of food required to cause diarrhea in healthy volunteers • Food acts as a buffer Vibrio cholerae virulence mechanisms • Infection with V. cholerae O1 / O139 begins with ingestion of contaminated food or water • Colonization of the intestines follows • Cholera toxin is produced • Severe diarrhea occurs with excessive loss of water and electrolytes
3/13/2016 Vibrio cholerae HOW IT SPREADS virulence mechanisms Produces a number of other extracellular toxins that are harmful to the host cells Other virulence factors Flagella,LPS,capsule,colonization factors Vibrio mimicus Vibrio mimicus foodborne outbreaks Known as the sucrose-negative V.cholerae ·Gasteroenteritis Distinctly different to V cholerae based on biochemical tests Associated only with consumption of seafood Causes gastroenteritis and may cause ear infections In US,raw oysters mainly Reservoir:aquatic environment ·In Japan,raw fish Free in the water Associated with roots of aguatic plants and plankton(60,000 CFU per gram) 10
3/13/2016 10 Vibrio cholerae virulence mechanisms • Produces a number of other extracellular toxins that are harmful to the host cells • Other virulence factors • Flagella, LPS, capsule, colonization factors Vibrio mimicus • Known as the sucrose-negative V. cholerae • Distinctly different to V cholerae V. cholerae based on based on biochemical tests • Causes gastroenteritis and may cause ear infections • Reservoir: aquatic environment - Free in the water - Associated with roots of aquatic plants and plankton (60,000 CFU per gram) Vibrio mimicus foodborne outbreaks • Gasteroenteritis • Associated only with consumption of seafood • In US, raw oysters mainly • In Japan, raw fish
