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

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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

  • 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

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

  • 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

Symptom of Botulism: Flacid 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

  • 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


Dehydration - Tenting of Skin

Life Cycle of V. Cholerae

One Solution: Saris Folded 4 – 8 Times Can Filter Out Most Pathogens

  • 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

Soap; Water; Washing Hands

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