Food and Waterborne Disease Lecture 2024 PDF

ecture 38 Food and Waterborne Disease Waterborne Disease Foodborne 1. Water Treatment Disease 2. Fecal Coliforms 5. Listeria 3. Typhoid 4. Cholera 1. Overview aterborne Diseases Gastroenteritis common symptoms: diarrhea, nausea, abdominal pain, fev ~1.8 M deaths annually wor...

ecture 38 Food and Waterborne Disease Waterborne Disease Foodborne 1. Water Treatment Disease 2. Fecal Coliforms 5. Listeria 3. Typhoid 4. Cholera 1. Overview aterborne Diseases Gastroenteritis common symptoms: diarrhea, nausea, abdominal pain, fev ~1.8 M deaths annually worldwide Fecal-oral transmission Infectious agents: Bacteria: Cholera, Typhoid, etc Protozoa: Cryptosporidium, Giardia, etc Virus: e.g. Polio, Hepatitis A, etc Prevention: Wastewater treatment & Water Purification 2. Water Treatment Waterborne diseases 3. Fecal Coliforms Public Health and Water Quality Potable and recreational water are routinely tested for indicator organisms: Coliform: a generic term for Gram negative, non- sporulating facultatively aerobic rods that ferment lactose to makes gas within 48hr at 35C Fecal coliform: coliforms from the gut of warm blooded animals Escherichia coli: a common fecal coliform 3. Fecal Coliforms What would we put in a medium that is selective and differential for coliforms? A. lactose B. a pH indicator C. antimicrobials that inhibit Gram positives D. all of the above 3. Fecal Coliforms Public Health and Water Quality Testing for fecal coliforms and E. coli Membrane filter (MF) method 100ml water filtered onto a membrane Place membrane on selective & differential medium Determine CFU per 100ml water 3. Fecal Coliforms EMB agar: Selective & differential for coliforms Includes: lactose an inhibitor of Gram positives a pH indicator (fermentation of lactose produces acid) Figure 31.1a 3. Fecal Coliforms Public Health and Water Quality Testing for fecal coliforms and E. coli Most Probable Number(MPN) method Dilute the water sample Inoculate many tubes of a selective & differential medium Estimate cell number based on number of tubes that grow bacteria 4. Typhoid Typhoid Fever Symptoms: high fever, abdominal pain onset of symptoms 6-30 days without treatment lasts weeks to months, 25% mortality with antibiotic treatment, 1-4% mortality 3-5% of infected individuals will develop a chronic asymptomatic infection in the gall bladder (ie: typhoid Mary) https://www.npr.org/2020/06/23/882115755/theres-something- 4. Typhoid Typhoid Fever Infectious agent: Salmonella enterica serotype typhi Epidemiology: rare in developed nations endemic in much of Asia and Africa ~21 M cases and 161,000 deaths worldwide in 2013 (WHO) Reservoir: Humans are the main reservoir Transmission: Fecal-oral, contaminated water 4. Typhoid Typhoid Fever 1903 Ithaca Outbreak Ithaca lacked a secure water supply, no filtration 10-15% of incoming class subject to “freshman diarrhea” 1350 cases (10% population), 82 dead, 29 Cornell students died Workmen pour concrete to build the Six Mile Creek Dam in the summer of 1903. Poor sanitation caused a typhoid epidemic in Ithaca. 4. Typhoid Typhoid Fever Infection/Virulence S. enterica ser. typhi and Non-Typhoid Salmonella virulence factors: Fimbrae and flagella (adhesion) Type III secretion systems inject effector proteins Plasmids that convey Multi-Drug Resistance now common S. enterica ser. typhi unique virulence factors include: Salmonella pathogenicity island 7 encodes genes that produce: Polysaccharide Vi-capsule antigen: capsule that What would you consider to be the best way to prevent an outbreak of typhoid? A. Antibiotics B. Improve sanitation and potable water via appropriate water treatment C. Vaccine D. Wash your fruits and vegetables before eating! 5. Typhoid Typhoid Fever Detection: Selective & differential media Prevention: Wastewater Treatment & Water Purification Vaccine is 50-75% effective Antibiotic resistance is rising, many strains now resistant to common antibiotics, certain antibiotics are still effective 4. Cholera Vibrio cholerae and Cholera Symptoms: Diarrhea often mild Symptoms occur in 2-3 days, disease lasts 2-3 days 10-20% will have severe case In severe cases can lose up to 20 L per day Rice water diarrhea 50-60% mortality without treatment 20% mortality with treatment (water/electrolyte replacement, antibiotics) 5. Cholera Figure 31.3 5. Cholera Vibrio cholerae and Cholera Epidemiology: rare in developed nations endemic in Southern Asia pandemic cholera, 3-5 M cases and >100,000 deaths worldwide Reservoir: Coastal habitats (endemic) and humans (pandemic) Transmission: Fecal-oral, contaminated water 5. Cholera Infectious agent: Vibrio cholerae Gram negative, facultative pathogen Found in coastal habitats, lives on zooplankton and crustaceans, many strains degrade chitin More than 200 serotypes, few cause disease O1 classical strain 5th and 6th pandemics O1 El Tor strain 7th pandemic (ongoing) O139 8th pandemic (spreading) Non-O1 & non-O139 are nearly identical to pandemic strains but cause mild diarrhea and do not generate epidemics 5. Cholera In costal habitats V. cholerae can be found on copepod Appl & Environ Microbiol 67:3220 5. Cholera Vibrio cholerae and Cholera Virulence factors Cholera toxin (CT): an AB exotoxin encoded by ctxAB gene ctxAB found on CTXφ prophage (7kb element) CTXφ is a lysogenic filamentous bacteriophage Only V. Cholerae strains with CTXφ cause epidemics!! Toxin Co-regulated Pilus (TCP) colonization factor, required for biofilm formation, also receptor for CTXphi 5. Cholera Nature Reviews, 7:693  Cholera toxin causes diarrhea- helps V. cholorae get back into the water supply and find new hosts Cystic Fibrosis Transmembra ne Conductance regulator (CFTR) protein We saw CFTR earlier in the semester CF - recessive genetic disorder affecting ~1 in 2500 people (varies depending on population), mutation located in the CFTR Airway cells are hypertonic relative to the airway airway loses water to the airway cells and mucus becomes thick How may a Cystic Fibrosis patient respond to cholera infecti A.Just as susceptible as everyone else…diarrhea! B.More susceptible, more diarrhea C.Less susceptible, less diarrhea 5. Cholera Vibrio cholerae and Cholera Detection: Selective & differential media Prevention: Wastewater Treatment & Water Purification Simple Filtration (e.g. sari cloth) 3. Foodborne illness in the US Roughly 1 in 6 Americans (or 48 million people) get sick every year: 128,000 are hospitalized and 3,000 die. Norovirus – outbreaks in hospitals and cruise ships – est. cost $2 billion/yr US Department of Agriculture Economic Burden of Major Foodborne Illnesses Acquired in the United States (2015) estimates 9.4 million illnesses impose over $15.5 billion/yr 5. Listeriosis Agent: Listeria monocytogenes, Gram-positive (Firmicutes Phylum) bacterium found in soil, water etc. carried in intestinal tract of diverse mammals (5-10% of all people) and birds. [carrier – infected but shows no sign of disease] Survives well outside human body BUT also an Opportunistic Pathogen that may cause foodborne illness. ID50 unknown but may be Able to pass through strong barriers in the body: including blood-brain barrier and placental barrier Time lapse 150x normal http://cmgm.stanford.edu/theriot/movies.html Can you think of another pathogen we have discussed recently which also can alter the cell cytoskeletal machinery for its own purposes to aid infection? Malaria Rabies Cholera Chlamydia  Listeria is a Psychrotole rant bacteria https://www.cdc.gov/foodsafety/outbreaks/multistate-outbreaks/outbreaks-l ist.html Control of foodborne pathogens Sanitation and proper procedures in food processing plants, particularly pasteurization! At home, thorough preparation of food, careful storage, avoid cross-contamination from uncooked food to cooked foods Vigilance in susceptible populations How to prevent listeria outbreaks? A. Treat livestock with antibiotics B. Clean, potable water C. Routinely test food products for listeria contamination D. Heat (including Pasteurization) or UV irradiation treatments E. C and D