question

Endogenous

answer

Caused by organisms that are part of the normal microbial flora of the body
(Streptococcus and Enterococcus)

question

Exogenous Infections

answer

Caused by pathogens that come into the body from the outside
(C. difficile & helicobacter pylori)
Brought in through contaminated water and food.

question

Clinical Symptoms of Gastrointestinal Symptoms

answer

Fever, vomiting, abdominal pain and diarrhea

question

Watery Diarrhea

answer

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

question

Dysentery

answer

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

Unlock the answer

question

Enteric Fever

answer

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)

Unlock the answer

question

Dental and Periodontal Infections

answer

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

Unlock the answer

question

Endemic GI Infections

answer

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

Unlock the answer

question

Epidemic GI Infections

answer

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

Unlock the answer

question

Traveler's Diarrhea

answer

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

Unlock the answer

question

Food Poisoning

answer

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

Unlock the answer

question

Nosocomial Gastrointestinal Infections

answer

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

Unlock the answer

question

Plaque

answer

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

Unlock the answer

question

Formation of Dental Plaque

answer

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

Unlock the answer

question

Dental Carries

answer

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

Unlock the answer

question

Gingivitis

answer

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

Unlock the answer

question

Periodontitis

answer

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

Unlock the answer

question

Necrotizing Periodontal Disease

answer

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

Unlock the answer

question

Enterobacteriaceae

answer

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

Unlock the answer

question

Escheria coli

answer

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

Unlock the answer

question

Enterotoxigenic E. coli

answer

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

Unlock the answer

question

Enteropathogenic E.coli

answer

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

Unlock the answer

question

Enterohemorrhagic E. coli

answer

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

Unlock the answer

question

Shigella

answer

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

Unlock the answer

question

Pathogenesis of Shigellosis

answer

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

Unlock the answer

question

Salmonella

answer

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

Unlock the answer

question

Salmonella Gastroenteritis

answer

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

Unlock the answer

question

Typhoid Fever

answer

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

Unlock the answer

question

Vibrio

answer

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

Unlock the answer

question

Campylobacter Enteritis

answer

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

Unlock the answer

question

Heliobacter pylori

answer

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

Unlock the answer

question

Viral Infections of the Digestive System

answer

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

Unlock the answer

question

Rotavirus

answer

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

Unlock the answer

question

Enterovirus

answer

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

Unlock the answer

question

Hepatitis A

answer

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

Unlock the answer

question

Hepatitis B

answer

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

Unlock the answer

question

Hepatitis C

answer

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

Unlock the answer

question

Hepatitis D

answer

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

Unlock the answer

question

Hepatitis E

answer

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

Unlock the answer

question

Hepatitis G

answer

Similar to Hepatitis C
No treatment

Unlock the answer

question

Giardiasis

answer

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

Unlock the answer

question

Cryptosporidiosis

answer

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

Unlock the answer

question

Whipworm

answer

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

Unlock the answer

Infections of the Digestive System – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards