Know the causative agent for the following diseases: dental caries, shigellosis, typhoid fever, cholera, peptic ulcers and acute gastritis.
Dental caries: S. Mutans
Shigellosis: Shigella
Shigella dysenteriae - severe dysentery (worst kind, bacillary dysentery)
Shigella flexneri - dysentery
Shigella boydii - dysentery also Shigella, S. Sonnei Typhoid fever - Salmonella enterica serotype typhi
Cholera - Vibrio Cholerae
Peptic Ulcers- Helicobacter pylori
Acute gastritis - not sure.
What is the difference between watery diarrhea, dysentery and enteric fever?
Watery diarrhea - Develops quickly and occurs frequently once you have it
Dysentery - Has blood and pus in it (this is the main, important difference)
Enteric fever - Systemic, (although focus is still on intestinal system) slower to develop
How does food poisoning occur? How can you tell the difference?
Can result from two things:
-Infection: directly involves a pathogen
-Intoxication: Involves a toxin produced by a pathogen
Incubation time and severity depend on:
- Number of pathogens ingested --> infections.
- Amount of toxin ingested --> intoxications.
Incubation time is usually shorter in intoxications.
Intoxication may involve organs outside the digestive tract.
Botulism affects the central nervous system.
What is the developmental process for dental plaque and carries?
Tooth surface becomes covered by pellicle, bacteria adhere to pellicle. This is facilitated by bacterial adhesion molecules. The initial adherent is usually strep mutans. Adhered bacteria grow and are joined by additional organisms including gram-positive cocci and gram-positive rods. After
2-4 days, new layers of organisms have joined. These are followed by gram negative motile organisms. There can be as many as 400 species in
mature plaque
What are the main differences between gingivitis and periodontitis?
Gingivitis- Inflammatory condition- Limited to the marginal surfaces of the gingival- Does not involve loss of bone- Can be corrected- Will continue as long as dental plaque remains
Periodontitis- Infection of the gingival- Results in loss of supportive bone and ligaments- Responsible for most tooth loss in adults
What are the 5 types of E. coli?
Enterotoxigenic E. Coli (ETEC):
Toxin: Heat-labile and heat-stable
Lesion: Hypersecretion
Pathogenic gene location: plasmid
Transmission: fecal oral
Disease: Watery diarrhea
Enteropathogenic E. Coli (EPEC)
toxin: none
Lesion: Effacement (covering) of the small intestine
Pathogenic gene location: PAI
Transmission: Fecal-oral
Disease: Watery diarrhea
Enteroinvasive E. Coli (EIEC)
toxin: none
Lesion: Invasion and inflammation
Pathogenic gene location: large plasmid and PAI
Transmission: Fecal Oral
Disease: Dysentery
Enterohemorrhagic E. Coli (EHEC)
Toxin: Shiga toxin
Lesion: Effacement (covering) of colon and hemorrhage
Pathogenic Gene Location: PAI
Transmission: Fecal-oral, cattle
Disease: bloody diahrrea
Enteroaggregative E. Coli (EAEC)
toxin: none
lesion: adherent biofilm
pahtogenic gene location: none
transmission: none
disease: mucoid watery diarrhea
Common
Toxin: hemolysin
Lesion: inflammation
Pathogenic gene location: none
Transmission: Adjacent flora
Disease: Opportunistic
Where does Salmonella and Campylobacter infection usually come from?
Poor water quality, fecal contamination, undercooked meat, contaminated meat, pets
Hepatitis A, B, C: transmission, chronicity, severity
Hep A
Transmission: fecal-oral, sexal
Chronicity: None
Severity: Usually mild
Hep B
Transmssion: fecal-oral, sexual, transfusion
Chronicity: 10 %
Severity: moderate
Hep C
Transmission: sexual, tansfusion
Chronicity: >50
Severity: mild
the most common source of gastointestinal infection in the developed world is
E. campylobacter
-- back cook says a. salmonella but pg. 508 says clear as day campylobacter!
The causative agent for 80% of ulcer is
B. H. pylori
an infection that is limited to the marginal surfaces of the gum tissue is called
C. gingivitis
dental plaque is an example of
B. biofilm
which of the following are produced by e. coli?
E. all of the above
transmission of traveler's diahrea occurs through
B. contaminated food/water
bacillary dysentery is caused by
B. shigella
serotypes of salmonella can be identified by
B. O antigens
the most important complication of typhoid fever is
C. perforation of the colon wall
the disease cholera is caused by
A. colonization of the entire intestinal tract
which of the following has now been classified as hepatovirus?
D. hep a
chronic carriers are the main reservoirs for
D. hep b
the intestinal parasite Giardia is found in
E. all of the above
rice stools are characteristic of
C. cholera
most of the normal microbil flora of the digestive system are found in
B. large intestines
poltury products are alikely source of infection by
