Infections of the Digestive System – Flashcards

Caused by organisms that are part of the normal microbial flora of the body

(Streptococcus and Enterococcus)

• Caused by pathogens that come into the body from the outside

(C. difficile & helicobacter pylori)

• Brought in through contaminated water and food.

• Most common
• Develops rapidly
• Accompanied by vomiting, gever and abdominal pain
• Caused by enterotoxin-secreting bacteria (Vibrio cholerae)
• Lasts 1 to 3 days

• Rapid onset
• Smaller in volume
• contain blood and pus
• Accompanied by cramps and abdominal pain but very little vomiting
• Center in the colon
• Not as much fluid loss
• Lasts longer about 3-7 days

• Systemic infection
• Prominent Feature: fever  and abdominal pain
• Diarrhea is mild
• Penetrations of enterocytes spread to the bile tract and liver
• Most common: Typhoid fever (Salmonella enterica serotype typhi)

• Most common: cavities and gingivitis
• Major source of problem: plaque

• Occur sporadically
• Most commonly caused by Campylobacter, Salmonella, and Shigella
• Most commonly seen in children

• Involve regional, national, and international populations
• Most common: cholera, typhoid fever and shigellosis
• Cholera and Typhoid fever are associated with contamination of water
• Shigellosis is associated with wars, crowding and poor sanitation
• In U.S. most frequent are E.Coli O157:H7, Cryptosporidium, and Giardia

• Caused by enterotoxigenic strains of E. coli (50%)
• Caused by Shigella (20%)
• Major source of transmission: improperly cooked food

• Intoxication: a toxin produced by a pathogen is involved
• Infection: pathogen is directly involved in the process
• Incubation time is shorter in intoxication than in infection
• Intoxication may involve organs outside the digestive tract
• Caused by failure to cook food adequately
• Salmonella, Clostridium perfringens and Staphylococcus aureus

• Traced to ill employee or contaminated food
• Caused by C. difficile and E. coli
• Symptoms include mild diarrhea
• C. difficile may be part of the patient's normal flora or from other patients

• Soft dental deposit that forms because of bacterial colonization of the surface of the teeth
• Insoluble in aqeous media
• Resists removal by brushing and flossing

• Adhesion of bacteria to the pellicle is followed by growth of bacteria 
• New layers of organisms pile on to the growing plaque
• Biofilm because it contains channels that transport nutrients to the bacteria

• Saliva protects against the establishment of many bacteria
• Caused by organisms that produce acid by-products
• Most common: streptococcus mutans, streptococcus salivarius, Lactobacillus, Acidophils and Actinomyces species
• Bacteria absorb and metabolize sugars producing acid by-products causing tooth decay

• Inflammatory condition of the gums
• Can be corrected
• Causes a loss of collagen
• Continues as long as dental plaque remains on a tooth

• Infection of the gums that result in the loss of supportive bone and ligaments
• Bacteria can invade the tissue

• Destruction of the mouth's soft tissue as well as the bone and ligaments
• Associated with emotional stress and poor oral hygiene
• Causes rapid ulceration of the tissues and pronounced bone loss
• Systemic and topical administration of antibiotics relieve the symptoms

• Gram-negative rod shaped bacteria
• Facultative anaerobes
• Damage the intestines
• Do not form spores
• 3 serotypes (O, K and H antigens)
• O antigen: LPS
• K antigen: Capsule
• H antigen: flagellum

• Gram-negative rods
• Lactose fermenting
• Have fimbraie and pili
• Produce toxins
• Pore-forming toxin: destroys the integrity of the cell
• Shiga toxin: blocks protein synthesis and  causes death of the cell
• Heat-labile toxin: accumulation of water and other lipids in the lumen of the intestine
• Heat-stable toxin: secretion of liquids and electrolytes into the lumen of the intestine

• Release a toxin
• Leading cause of mental retardation and malnutrition in underdeveloped countries
• Transmitted through consumption of food or water that is contaminated
• Adheres to the cells of the intestines
• Genes are found on plasmids
• Toxin causes water and electrolytes to flow into the intestine

• Transmisison is fecal-oral
• Infants are the reservoir
• Use fimbriae to form colonies on intestinal cells
• Secretes five proteins into the cell's cytoplasm
• Proteins inhibit cell signaling

• Produce shiga toxin
• Transmission: animals colonized with the pathogens
• Mostly caused by undercooked meat
• Attack the colon
• Mild: no treatment required
• Severe: liquid replacement required

• Don't ferment lactose
• Lack flagella
• Produce the shiga toxin
• Causes dysentery
• Transmission: fecal-oral route, person to person or consumption of contaminated food or water
• Most severe: bacillary dysentery

• Trigger an intense acute inflammatory response of the colon
• Kill the M cells of the colon and phagocytes
• Use an actin tail for transport
• Symptoms: fever, malaise and anorexia
• Treatment: antibiotics

• Multiple Pilli
• Gastroenteritis: nausea and vomiting followed by cramps and diarrhea
• Bacteremia: leads to septic shock and death
• Enteric Fever: fever and headache followed by constipation or diarrhea
• Chronic Infection: Bacteria enter the blood leading to myocarditis or infection of distal sites of the body

• Results from improper food handling (Poultry)
• Transmission from animal or human reservoirs
• Bacteria are engulfed by Mcells and enter the lamina propria initiating a powerful inflammatory response
• Can induce apoptosis in the cell

• Inhibit the release of the oxidative poisons used by macrophages to kill invading bacteria
• Hemorrhaging causes perforation of the wall of the colon or at the Peyer's patches
• Treatment: replacement of fluids and control of nausea and vomiting
• Vaccine available

• Gram-negative, non spore-forming rod shaped bacteria
• Found in salt water
• Facultative anaerobes
• Toxin causes a intestinal infection
• Spread by contaminated water and poor sanitation
• Results in dehydration, hypokalemia and metabolic acidosis
• Balancing liquid and electrolyte loss
• Treatment: Tetracycline

• Most common cause of diarrhea
• Primary reservoir: animals
• Transmission: ingestion of contaminated food or by direct contact with pets
• Most common source: undercooked poultry
• Produce a cytotoxin that arrests cell division
• Lasts 3-5 days
  

• Gram-negative rod shaped with flagella
• Urease enzyme: allows it to survive acidic environments
• Vacuolating cytotoxin: causes apoptosis in infected cells
• Transmission: person to person through fecal-oral route
• Most common cause of gastritis
• Symptoms: nausea and upper abdominal pain
• Treatment: antimicrobial agents

• Rapid onset diarrhea
• Characteristics: brief incubation periods, fecal-oral routes of transmission and vomiting

• non-enveloped, double-stranded RNA virus
• Common in infants and children
• Causes a decreased absorptive surface and decreased enzymatic function
• Vomiting, fever and diarrhea
• Complication: dehydration
• Severe cases require replacement of fluid and electrolytes
• Vaccine available

• Persistant to acidic environments
• Seasonal infection patterns and predisposed to temperate climates
• Fecal-oral transmission
• Virus is brought into the host cell and viral RNA is released into the cytoplasm
• No treatment

• Transmission: fecal-oral route
• Commonly caused by crowding and poor hygiene
• Onset of fever, anorexia, nausea, upper abdominal pain and jaundice
• Seen more in children
• No treatment just rest and adequate nutrition

• Chronic carriers are the main reservoir
• Transmission: close contact with body liquids
• Onset of fatigue, loss of appetitie, nausea, and upper abdominal pain
• Can lead to cirrhosis, liver failure, or hepatocellular carcinoma
• Vaccine available

• Transmission: blood transfusions and sex
• Most of those infected become carriers of the infection and progress to chronic hepatitis
• Leading cause of liver transplants
• Therapy with interferon-alpha and ribavirin

• requires the presence of Heaptitis B
• Often seen in intravenous drug abusers
• Co-infection with Hepatitis B or superinfection of people already infected with Hepatitis B
• Cause a relapse, reoccurence of jaundice and increased risk of cirrhosis
• Treatment: interferon-alpha

• Transmitted by the fecal-oral route
• Resembles Hepatitis A
• Causes disease in only pregnant women
• Associated with contaminated drinking water
• No treatment

• Similar to Hepatitis C
• No treatment

• Can survive in cold water for months and is resisitant to chlorine
• Transmission: fecal-oral route
• Found in fish, amphibians, reptiles, brids and mammals
• Contaminated water or food
• Diarrhea, abdominal cramping, nausea and fever
• Lead to significant weight loss and malnutrition
• 4 drugs available

• infects the intestinal tract of both humans and other animals
• Domestic animals are the reservoir
• Person-to-person transmission
• Transmission: fecal-oral route, contamination of food and water
• Watery diarrhea
• No treatment needed

• Significant mucosal damage, blood loss and anemia in children
• Asymptomatic infections: no need for treatment
• Severe disease: mebendazole