Chapter 20 - Food Poisoning, Chronic Diarrhea, Other Infections

food poisoning

• Severe nausea and frequent vomiting accompanied by diarrhea

• Others sharing meal have same symptoms

• Onset within 1-6 hours

• Symptoms in the gut that are caused by a preformed toxin of some sort from:

  • Staphylococcus aureus, Bacillus cereus, Clostridium perfringens

Staphylococcus aureus exotoxin (food poisoning)

• Toxins produced when the organism is allowed to incubate in food

• outgrows most bacteria in environments with high temperature and high osmotic pressure

• is heat-stable; inactivation requires 100°C for at least 30 min

• Ingested toxin acts on the gastrointestinal epithelium

Clostridium perfringens (food poisoning)

• Forms endospores, produces an exotoxin

• Acute abdominal pain, diarrhea, and nausea in 8 to 16 hours

Bacillus cereus (food poisoning)

• Forms endospores – spores survive heating, germinate, and produce toxins

  • One causes a diarrheal-type disease

  • The other causes an emetic or vomiting disease

chronic diarrhea

• Diarrhea lasting longer than 14 days

• Irritable bowel syndrome and ulcerative colitis: 

• Neither caused by a microorganism

• AIDS patients suffer from this caused by opportunistic microorganisms

Cyclospora (chronic diarrhea)

• Fecal-oral transmission

• Most cases associated with consumption of fresh produce and water contaminated with feces

• Disease occurs worldwide and is not spread from person to person

Cyclospora cayetanensis

What causes Cylospora?

protozoa

What is Cyclospora cayetanensis classified as?

Giardia duodenalis

What causes Giardia?

flagellated protozoa

What is Giardia duodenalis classified as?

Giardia (chronic diarrhea)

• Flagellated protozoan

• Attaches to the intestinal wall

• Prolonged diarrhea, abdominal pain, and flatulence

• transmitted in contaminated water

dental plaque

biofilm involved in the formation of dental caries (tooth decay)

Streptococcus mutans

Most common causative organism of dental caries?

Streptococcus mutans

• Gram-positive coccus

• Converts sucrose to lactic acid

• Produces sticky polysaccharides that contribute to biofilm formation

dental caries

• most common infectious disease of human beings:

  • Involves the dissolution of solid tooth surface due to the metabolic action of bacteria

  • Caries penetrate from enamel into the dentin

• Decay can reach pulp, which contains the blood supply and nerve cells

  • May advance to the soft tissues, leading to abscesses

gingivitis

Inflammation and infection of the gums

periodontitis

Bone and tissue supporting the teeth are destroyed

calculus

hard, porous substance produced above and below gingival margin; induces varying degrees of periodontal damage

mumps virus

What causes mumps?

mumps

• targets the parotid salivary glands

  • Fever, nasal discharge, muscle pain, and malaise

• Most infections are self-limiting with complete, uncomplicated recovery and permanent immunity

• Transmitted through salivary and respiratory secretions

• Symptomatic treatment to relieve fever, dehydration, and pain

Heliobacter pylori

What causes peptic ulcer disease?

bacteria

What is Heliobacter pylori classified as?

Hepatitis

• Inflammatory disease marked by necrosis of hepatocytes and an inflammatory response that swells and disrupts the liver architecture

• Jaundice

• caused by viruses

jaundice

yellow tinge in the skin and eyes caused by bilirubin accumulation in the blood and tissues

Hepatitis C Virus

• Parenteral transmission; often blood transfusions

• Destroys the liver by using genetic variation to evade the immune response

• Kills more in the U.S. than AIDS

• 85% of cases become chronic

  • 25% develop liver cirrhosis or cance

helminths

• Barely visible roundworms (0.3 mm)

• Huge tapeworms (25 m)

• Three categories:

  • Nematodes (roundworms)

  • Trematodes (flukes)

  • Cestodes (tapeworms)

eosinophilia

• Increase in granular leukocytes called eosinophils

• Have a specialized capacity to destroy helminths

• Hallmark of helminthic infection

Helminth infections

acquired through:

• Fecal-oral route

• Penetration of the skin