study

Disease

Causative Agent

Virulence Factors of the Pathogen

Symptoms

Transmission

Dental caries, gingivitis, periodontal disease

Streptococcus mutans a frequent cause of caries

Porphyromonas gingivalis causes periodontal disease.

Dextran and pili allow biofilm formation on tooth.

Proteases break down gingival tissue.

Caries: holes or pits in the teeth

Periodontal disease: swollen or bleeding gums, gums that are tender to the touch and appear shiny, or gums that appear bright red or red-purple in color, with loose teeth and a foul breath odor.

Diets high in sucrose increase risk of decay.

Peptic Ulcers

Helicobacter pylori

Flagella enable burrowing through stomach lining.

Adhesins facilitate attachment to gastric cells

Urease neutralizes stomach acid.

Abdominal pain

Fecal-oral transmission likely. Stress may worsen ulcer symptoms

Bacterial Gastroenteritis

Presence of bacteria in the stomach

 No particular virulence factors

Nausea, vomiting, diarrhea, abdominal pain, and cramps

Dysentery produces loose, frequent stool containing mucus and blood.

Associated with contaminated food or water and poor living conditions

Traveler's Diarrhea

Escherichia coli

Enterotoxins, adhesins, fimbriae, and various toxins (e.g., Shiga-like toxin), Type III secretion system

Diarrhea, nausea, and vomiting

Fecally contaminated food or water

Campylobacter Diarrhea

Campylobacter jejuni (most common cause of bacterial gastroenteritis)

Adhesins, cytotoxins, endotoxin

Nausea, vomiting, diarrhea, abdominal pain, and cramps

Dysentery produces loose, frequent stool containing mucus and blood.

Confirmed by presence of bacteria in the stool

Chickens are the main source of human infections.

C. diff. (Antimicrobial-Associated) Diarrhea

Clostridium difficile

Antimicrobial use facilitates overgrowth of C. difficile

C. difficile produces two toxins: Toxin A and Toxin B

Watery, foul-smelling bowel movements

Pseudomembranous colitis occurs in severe cases

Byproduct of modern medicine

Any antimicrobial can trigger disease.

Salmonellosis and Typhoid Fever

Salmonella enterica serotypes Enteritidis and Typhimurium 

Bacteria tolerate acidity of stomach and pass to the intestine.

Toxins disrupt numerous cellular activities.

High fever (40°C), headache, muscle and stomach pain, malaise, loss of appetite, rose-colored spots

Typhoid fever acquired by contaminated food or water

Salmonellosis often acquired by consuming contaminated eggs

Cholera

Vibrio cholerae

Cholera toxin

Type III secretion system

Shiga toxin

"Rice-water" stool

Fecally contaminated water

Bacterial Food Poisoning (Intoxication)

Staphylococcus aureus

Five enterotoxins

Nausea, vomiting, diarrhea, cramping

Outbreaks associated with social functions