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Foodborne and Waterborne Bacterial Diseases

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Foodborne and Waterborne Bacterial Diseases. Intoxications Botulism Staphylococcal food poisoning Clostridial food poisoning. Infections Typhoid fever Salmonellosis Shigellosis E. coli diarrheas Peptic ulcer disease Campylobacteriosis Brucellosis Cholera Bacillus cereus Others.

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foodborne and waterborne bacterial diseases
Foodborne and Waterborne Bacterial Diseases
  • Intoxications
    • Botulism
    • Staphylococcal food poisoning
    • Clostridial food poisoning
  • Infections
    • Typhoid fever
    • Salmonellosis
    • Shigellosis
    • E. coli diarrheas
    • Peptic ulcer disease
    • Campylobacteriosis
    • Brucellosis
    • Cholera
    • Bacillus cereus
    • Others
Portal of Entry – Mouth  G.I. Tract
    • Intoxications - illnesses in which bacterial toxins are ingested with food and water
    • Infections - illnesses in which live bacterial pathogens are ingested and grow in the body
The incubation period is the time between
    • consumption of contaminated material
    • appearance of symptoms
  • Clinical symptoms and duration of illness depend on:
    • the toxin or microbe (what it is)
    • the infectious dose (how much you ate)
  • Demographics can make individuals more or less prone to food/waterborne illness
    • For example, age or sanitary conditions
    • We usually lose the “bookends” – the vy young and the

vy old. With so many opposite characteristics, what do these 2 different groups have in common?

the problem contact with fecally contaminated food and water
The Problem:Contact with Fecally Contaminated Food and Water

Ex: Ritual Bathing in the Ganges

Sewage Meets Ganges

There Are Several Ways Foods or Water Become Contaminated
    • Meat can be infected during improper slaughter procedure
    • Fruits and vegetables can be washed with contaminated water
    • Infected humans can contaminate food they handle through the fecal-oral route
Cross-contamination can occur:
    • between foods
    • via knife, cutting board, etc.
  • Water contamination can occur by defecation of infected individuals in public water sources
  • Improperly stored foods can contain large numbers of pathogens because of rapid multiplication

Figure 10.3, page 283

foodborne intoxications
Foodborne Intoxications
  • Bacterial Food Poisoning Can Result from an Intoxication


    • Clostridium botulinum is the source of botulism
      • C. botulinum produces a deadly exotoxin that attacks the nervous system, causing flaccid paralysis
      • Death is caused within 1-2 days of symptom onset by respiratory paralysis
If treated early, large doses of antitoxins can neutralize the toxin
  • Most outbreaks are related to home-canned foods or from foods eaten cold (heat destroys the toxin)
  • Wound botulism occurs when a wound is infected with C. botulinum
  • Infant botulism, a.k.a floppy baby syndrome, frequently occurs when an infant is fed honey
  • Minute doses of botulinum toxin can be used to treat movement disorders and to remove facial wrinkles

Symptoms start ~ hours 1 ½ days after eating food

  • 7 strains AG – we are most affected by

A,B & E

  • In U.S, around 100 cases /year
  • U.S., Germany began weaponizing toxin in WWII, Iraq deployed missiles filled with botulinum toxin in 1990.
Staphylococcal Food Poisoning
  • Staphylococcus aureus causes staphylococcal food poisoning
    • Toxins are often consumed in protein-rich foods such as:
      • meat and fish
      • dairy products
      • The enterotoxin causes gastroenteritis for several hours
      • Symptoms: nausea, vomiting and diarrhea starting at T+30min

Figure 10.3a, page 283

Food is often contaminated by:
    • boils or abscesses on a handler’s skin
    • through sneezing
  • Proper handling, refrigeration, and heating help decrease the risk of contamination

Figure 10.3b, page 283

Clostridial Food Poisoning
  • Clostridium perfringens
  • commonly contaminated are meat, poultry, and fish
  • Clinical symptoms require a high infectious dose, and take 8-24 hours to appear

Figure 10.5, page 286

foodborne and waterborne infections
Foodborne and Waterborne Infections
  • Most GI infections require a large dose of bacteria; Shigella and E. coli O157 are exceptions

Typhoid Fever

    • It is caused by Salmonella enterica serotype typhi (S. typhi)
  • S. typhiis transmitted by the five Fs:
    • Flies
    • Food
    • Fingers
    • Feces
    • Fomites

Figure 10.6, page 287

S. typhi is acid resistant – can survive in sewage and the stomach
    • It passes through the stomach to the small intestine
      • It causes ulcers, bleeding, and pain
      • CNS symptoms – delirium, coma
      • Rose spots on the skin, not much diarrhea, but mucus and blood in the feces
  • Invasion into cardiovascular system

can occur

    • Rose spots indicate blood hemorrhage
  • Vaccines contain dead or attenuated S. typhi or polysaccharides from S. typhi capsule – effective for ~ 2yrs.
  • Can Be Contracted from a Variety of Foods
  • Salmonellosis is usually caused by S. enterica serotype enteritidis or typhimurium
  • Gastroenteritis occurs 6 - 48 hours after a large infectious dose

Figure 10.7b, page 290

Symptoms include, fever, nausea and/or vomiting, abdominal cramps, diarrhea, dehydration
  • Rarely fatal –(but you feel like you want to die!)
  • They can also be transmitted by live animals - milk
  • Chickens and reptiles can carry Salmonella – eggs also

Figure 10.7a, page 290

Shigellosis (Bacterial Dysentery)
  • Occurs Where Sanitary Conditions Are Lacking
  • Shigellosis is primarily caused by Shigella sonnei
    • S. dysenteriae causes epidemics in the developing world
  • Contaminated foods commonly include:
    • Eggs
    • Vegetables
    • Shellfish
    • Dairy
An infectious dose requires as few as 10 S. sonnei individuals
  • Shiga toxin production in the intestinal epithelium destroys GI epithelial cells ulceration of the intestines  bloody stools
  • Infection of the large intestine can lead to fatal dysentery
  • ~18,000 cases/year in U.S.
  • No vaccine is available
Typhoid fever, Shigellosis, Campylobacteriosis are the main GI tract infections that cause bloody stools
  • Causes dysentery = extremely watery diarrhea  enormous fluid loss
  • Cholera is caused by Vibrio cholerae
  • V. cholerae are often consumed with raw oysters and water
  • The cells are susceptible to stomach acid
    • A large infectious dose is needed to colonize the intestines

Figure 10.8, page 291

Cholera toxin causes unrelenting loss of fluid and electrolytes through diarrhea (up to 1 L/hour)
  • In untreated, fluid loss leads to shock and coma
    • Can kill a healthy human adult in 3 days
  • Antibiotics and restoration of water and electrolyte balance are effective in treatment
  • Vaccines using dead V. cholerae are available
  • Immunity lasts for ~ 6 months
E. coli Diarrheas
  • Cause Various Forms of Gastroenteritis
  • Escherichia coli is normally found in the human intestine, but certain serotypes are pathogenic
  • “Travelers trots”, “Montezuma’s revenge”, infantile diarrhea, E. coli O157:H7

Figure 10.9, page 293

Enterotoxic E. coli (ETEC) produce a toxin that causes gastroenteritis – is noninvasive
    • a.k.a. traveler’s diarrhea, infantile diarrhea
  • Enteropathogenic E. coli (EPEC) cause diarrhea in infants, or particularly where sanitation is lacking – “moderately invasive” – symptoms caused mostly by inflammation, not toxins
Enterohermorrhagic E. coli(EHEC) is often transmitted by undercooked ground beef (or bagged spinach!)
    • O157:H7 – refers to surface identity markers
    • Contamination also occurs in unpasteurized milk and juice, sprouts, lettuce, and salami
    • Infection can occur from contact with cattle or swimming in/consuming contaminated water
    • A small infectious does causes hemorrhagic colitis 1-8 days after infection
    • Complications can occur in young children or the elderly, but most cases resolve in 5-10 days
    • Most serious complication is

hemolytic uremia

Figure 10.10, page 295

Gastric Ulcer Disease
  • Can Be Spread Person to Person
  • Helicobacter pylori
  • It is unknown how H. pylori is transmitted but it likely involves contaminated food or water – kissing???
  • People can infect dogs??
  • The bacteria produce urease, which in turn produces ammonia
    • Ammonia neutralizes acid in that area of the colony, allowing the bacteria to survive

Microfocus 10.4b, page 296

The ammonia, and an H. pylori cytotoxin destroy mucous-secreting cells
    • This creates an ulcer
  • A urea breath test is used – detects radioactive CO2 coming from hydrolysis of urea


C = O 2NH3 + CO2


Figure 10.11, page 297

  • Results from Consumption of Contaminated Poultry or Dairy Products; drinking from a stream
    • Campylobacteriosis is the most common cause of bacterial gastroenteritis in the U.S.
    • Campylobacter jejuni is transmitted through the fecal-oral route, usually by poultry

Figure 10.12, page 298

Colonization of the intestine occurs during a 2-7 day incubation period
  • Guillain-Barré Syndrome is a rare nervous system disease that may develop

Usually Manifests Itself as Meningoencephalitis or Septicemia

  • Is caused by Listeria monocytogenes – a psychrophile
  • It is transmitted by:
    • food contaminated with feces
    • contaminated animal products like cold cuts and soft cheeses

Figure 10.13, page 299

Listeriosis usually affects pregnant women, the elderly, or immunocompromised
  • Meningoencephalitis is characterized by:
    • headaches
    • stiff neck
    • delirium
    • Coma
  • Septicemia is a blood disease involving high numbers of infected monocytes
  • Infection of the uterus can occur in women – can cause mental retardation and developmental abnormalities in unborn children – a TORCH disease
Several Other Bacterial Species Can Be Transmitted through Food or Water
    • Brucella species cause brucellosis, which affects people who work with large ruminant animals
      • Infection can occur through eyes, abrasions, or consumption of contaminated dairy products
      • The bacteria are transported to the spleen and lymph glands upon infection, causing flu-like symptoms
      • Brucellosis is also called undulant fever because of a specific fever pattern
Vibrio species other than V. cholerae can cause illness
    • V. parahaemolyticus is a common problem where large amounts of seafood are consumed
    • V. vulnificus is transmitted by oysters and clams
      • It can cause a deadly systemic infection
      • Can also cause a “flesh-eating disease”
      • Found in Gulf coast waters
Bacillus cereus can cause diarrhea or vomiting
    • Infections usually occur from eating contaminated cooked grains
    • Produces a toxin that causes emesis
    • Can throw blood pH off
  • Plesiomonas shigelloides causes intestinal illness
    • Infection is often from eating raw seafood
  • Aeromonas hydrophila cause both cholera-like and dysentery-like diarrheas