ch. 20 Gastrointestinal MCB Flashcards

Describe the events that lead to dental caries and periodontal disease?

dental caries:
- S. mutan or other streptocci attach to the tooth
healthy tooth with plaque, decay in enamel, advanced decay,
decay in dentin and decay in pulp
periodontal disease:
-(inflammation and degeneration of structures that support the teeth):
healthy gingivae, gingivitis, periodontal pockets and periodontitis

Dental cariers

Major cause of caries is Streptococcus mutans.
- they ferment dietary carbohydrates into acids
Contributers: bad diet, plaque, microorganisms

Inflammation of the gums
- cause bones loss lead to periodontal disease


This disease results from inflammation of periodontal tissue?

periodontal disease (fusopirochetal disease)

Periodontal disease causes and is due to?

due to poor hygiene leads to increased subgingival plaque, which can
be populated by bacteria
characterized by:
ulcers & bleeding along the gingival margin
degradation of periodontal ligaments and bone
loosen or lost teeth

List the ways food or water can become contaminated?


What will help decrease the risk of contamination?

Proper handling, refrigeration, and heating

a method used for detecting single strains of bacteria. It is used to
trace the source of outbreaks of infections. The viruses that infect
bacteria are called bacteriophages
("phages" for short) and some of these can
only infect a single strain of bacteria.

phage typing

causative agents:
Staphylococcus aureus suspect foods:
protein-rich foods: meat &fish, dairy products; that was left
unrefrigerated for a few hours signs: intoxication:
enterotoxin (super-antigen) causes gastroenteritis for several hours
-Food is often contaminated by boils or abscesses on a handler�s
skin through sneezing

symptoms: Nausea,
vomiting, and diarrhea

treatments: none
*body purging

staphylococcal food poisoning

causative agents:
Shigella spp. suspect foods:
contaminated foods/ water signs: shiga exotoxin
(same toxin as STEC; both conjoined)

symptoms: Tissue
damage and dysentery; fever abdomindal pain and watery diarrhea-> bloody

diagnosis: stool culture

treatments: Quinolones
-shigella enters epithelial cell-multiplies inside
cell-invades neighboring epithelial cells, avoids immune
defenses-abscess forms as epithelial cells are killed by
infection * Another name: Bacillary Dysentery


causative agents: Salmonella enterica suspect foods:
gut of many animals, chicken, turkey, eggs, dairy products *
contaminated meatsigns: dehydration, causes sepsis (gets into
lymphatic system)symptoms: nausea &
diarrheatreatments: oral rehydration


causative agents: Salmonella typhi transmission:
spread when a person drinks or eats food and water contaminated by
human waste (stool or urine) containing Salmonella typhi bacteria.
signs: Bacteria spread throughout body in phagocytes
symptoms:High fever, significantmortality; severe loss of appetite
treatments: Quinolones; cephalosporins
* 1�3% of recovered patients become chronic carriers

typhoid fever

causative agents:
Vibrio chloerae suspect foods: consumed
with raw oysters and water

signs: involves
enormous fluid loss; imbalances of electrolytes-> problems with
heart symptoms:
dehydration; cloudy water stools-> mortality treatments: saline/
antibiotics (tetracycline) ; Oral or intravenous hydration
* The cells are susceptible to stomach acid
� A large infectious dose is needed to colonize the intestines


What is the intoxication that can cause diarrhea or vomiting?
infection usually occur from eatingcontaminated cooked grains
found: in soil, grains, rice dishes

Bacillus cereus

Why do bacterial GI infections have a longer incubation period than intoxications?

because bacterial cells must establish themselves in the body after ingestion

What is the cornerstone of diarrhea treatment, especially for small
bowel infections that produce a large volume of watery stool output?

oral rehydration treatment

What is the main difference between viral and bacterial gastroenteritis?


Although vomiting is common in viral gastroenteritis, it is less
common in bacterial gastroenteritis.

Bacterial gastroenteritis results in large volume watery
diarrhea and abdominal cramps.

causative agents:
E.coli, Salmonella spp., shigella spp., bacillus cereus
suspect foods:
poor sanitation, contaminated water/foods, improperly processed/
preserved foods signs: produces
inflammatory condition when bacteria causes an infection in your
gut**Dehydration is a common but seriouscomplication of gastroenteritis

gastroenteritis often produces an inflammatory condition

symptoms: diarrhea, dysentery
treatments: oral rehydration therapy
*longer incubation period due to symptoms growing

bacterial gastroenteritis

What is involved in gastric ulcers/ peptic ulcer disease?

causative agents: helicobacter pylori
PUD: painful sores or ulcers in the lining of the stomach or
first part of the small intestine, called the duodenum.
transmission: spread to person to person
due to: bad diet, smoking, drinking
symptoms: bloating, heartburn, nausea/vomiting, burning pain in
middle/upper stomach b/w meals/ night, dark black stools
-Produce urease, which in turn produces ammonia
-Neutralizes acid in stomach, allowing the bacteria to survive

Pathogen: enterotoxigenic; E.coli Gastroenteritisi
symptoms: watery diarrhea
intoxication/infection: infection; endotoxin
treatment: oral rehydration

traverler's diarrhea

difference b/w exotoxin & endotoxin

a toxin released by a living bacterial cell into its
surroundings (outside)
endotoxin: (inside) a toxin that is present inside a bacterial
cell and is released when the cell disintegrates. It is sometimes
responsible for the characteristic symptoms of a disease, e.g., in botulism.

Pathogen: shiga-toxin-prodcuing E.coli
symptoms: Shigella-like dysentery; hemorrhagic colitis, kidney
damage, internal bleeding
intoxication/ infection: infection Shiga exotoxin
treatment: quinolones; cephalosporins


What is the causative agent for the tapeworm?

Taenia solium

Whats the causative agent for Nermatode?
what type of worm?

Enterobius vermicularis ; pinworm
Enterobiasis- Pronounced anal itching when the mature female
emerges from the anus and lays eggs. - Can also suffer from
disrupted sleep, nausea, abdominal discomfort, and diarrhea
- Rapid test can be performed by pressing a piece of transparent
adhesive tape against the anal skin then microscopy

Whats the primary symptom of helminthic disease?

Intestinal Distress

**most common flagellate isolated in clinical specimens
�Both trophozoites and cysts escape in the stool,but cysts play a
greater role in transmission- Giardia cysts can survive for 2
monthsin the environment- cysts are usually ingested with food
- infectious dose is 10� 100 cysts
�Avoiding drinking from freshwater sources isthe major
preventative measure
�Typical symptoms- diarrhea of long duration- abdominal
pain- flatulence- stools have a greasy, malodorousquality to
them- fever is usually not present

Giardia lamblia
-protozoan disease

**one of the most significant pathogenic amoeba- simple life
cycle alternates between a large trophozoite and a smaller; nonmotile
cyst - amoeba secretes enzymes that dissolve tissues,
actively penetrating deeper layers of the mucosa, and leaving
ulcerations - dysentery, abdominal pain, fever,
diarrhea, and weight loss- life-threatening manifestations
include hemorrhage,perforation, appendicitis, and tumor-like growths
called amoebomas

Entamoeba histolytica

What condition is caused by Helicobacter pylori? Why would the
pathogen be able to survive in the very acid condition of the stomach?

Helicobacter Peptic Ulcer Disease and it is able to survive in the
very acidic condition of the stomach because it produces large amounts
of an especially efficient urease, an enzyme that converts urea to the
alkaline compound ammonia, resulting in a locally high pH in the area
of growth.

What are the 2 forms of E.coli Gastroenteritis?

traveler's diarrhea & STEC

this can cause Gastroenteritis
normally found in the human intestine, but certain serotypes are
pathogenic�Transmission occurs through the fecal-oral route
Attach to intestinal cells with fimbriae Produce
toxins May aggregate (grow &multiply)

E. Coli

causative agents:
mumps virus modes of
transmission: spreads easily from person to person through
infected saliva; viral & respiratory route/ droplet contact
sites of infection:
salivary glands symptoms: fever, nasal
discharge, muscle pain, malaise

-enlarged jaw tissues caused by swollen salivary glands
males: lead to swollen testicles ( infertility & high fever)
*alternative name: infectious parotitis


What are the 2 very common causes for viral gastroenteritis?

rotavirus, norovirus

causative agents: rotavirus, norovirus

Disease: Viral gastroenteritisSymptoms: Vomiting,
Diarrhea, 1 weekIncubation: 1-3 daysDiagnosis: Oral rehydration

Norovirus: Disease: Viral
GastroenteritisSymptoms: Vomiting, diarrhea, 2-3
daysIncubation: 14-48 hrDiagnosis: Oral rehydration
modes of transmission: ingestion; close contact with infected
person; fecal-oral route(by poor hygiene & sanitiation, touching
contaminated fecal material)
* referred to as stomach/ intestinal flu
* highly contagious

viral gastroenteritis

Name the 2 mycotoxin intoxications?

ergot poisoning & aflatoxin poisoning

Why is mumps included with the diseases of the digestive system?

It can cause inflammation of the salivary glands which is a part of
the digestive system

Identify the causes of ergot poisoning?

causative agent: Claviceps purpurea (fungus)symptoms:
Reduced blood to limbsinfection/intoxication: Mycotoxin in
graindiagnosis: Sclerotia in food
treatment: none

Identify the causes of aflatoxin poisoning?

causative agent: Aspergillus flavus (fungus)symptoms:
Liver cirrhosis; liver cancerinfection/intoxication: Mycotoxin
in food: peanuts in natural statediagnosis: Immunoassay for
toxin in food
treatment: none

difference between infection vs. intoxication?

infection: growth of a pathogen
- incubation (12hrs to 2 weeks)
- fever
Intoxication: ingestion of toxin
( dysentery- tissue damage, pus in stool)
- symptoms appear (1 to 48hrs) after ingestion
treatment: oral rehydration therapy
*both are self-limiting