Week 11 - Topic 1: GI Tract Disease & Bacterial Infection Flashcards
What is an outbreak?
When the number of cases exceeds what has been defined as “normal” in an area/season
What are the 6 type of GI infections?
1) Colitis
2) Diarrhea
3) Dysentery
4) Enteritis
5) Gastritis
6) Gastroenteritis
What is colitis?
Inflammation of large intestine
What is dysentery?
> 20-30 watery stools per day that may contain blood, mucus or pus
What is gastroenteritis?
Inflammation of the mucosal lining of stomach and intestines
What is diarrhea?
Frequent discharge of liquid fecal matter (takes the shape of a container)
What is enteritis?
Inflammation of the small intestine
What is gastritis?
Inflammation of the mucosal lining of the stomach
How does the stomach protects itself against microorganisms?
Has a pH < 1 very acidic
How does the small intestine protects itself against microorganisms?
- Bicarbonate-buffered pancreatic juices (pH = 9)
- Enzymes (lysozymes, proteases, lipases) inhibit growth
- Peristalsis dislodges bacteria
Where in the GI tract do we find the most flora?
Large intestine
A lot of gram -
What normal flora do we find in the stomach?
Aerobic organisms: lactobacilli and streptococci
What normal flora do we find in the small intestine?
Lactobacilli
E coli
Enterococcus faecalis
What normal flora do we find in the large intestine?
Anaerobic organisms: lactic acid bacteria, bacteroids, bifidobacterium bifidum
What are the 6 major causes of diarrhea?
1) Rx (iron, Abx)
2) Psychological stress
3) Allergies
4) Disease (Chron’s)
5) Procedures (gall bladder or stomach surgery)
6) Pathogens –> contagious
What prevents flora from overgrowing and how?
Neutrophiles
Keep the flora in the gut lumen contained (esp in large intestine) by being recruited when the flora secrete chemotaxins
What can reduce the # of neutrophiles in our body and affect GI bacteria?
Bone marrow fails
Over growth of pathogens
Chemo
Radiation
What happens when there are not enough neutrophiles to contain flora in GI tract?
Gut flora translocate to the bloodstream = secondary bacteremia
Name some GI infection sx that is not diarrhea
Nausea Vomiting Abdominal pain Cramping Bloody stool Liquid stool Loss of appetite Weight loss Bloating Increased gas Fatigue Body aches, headache, fever, and other flu-like symptoms
What must you document with regards to bowel patterns?
Frequency of stool passage over 24h Color Consistency Associated Sx Odour Bristol stool chart
–> compare with normal pattern of pt
True or False: When you send out a sample for GI infection diagnosing, the lab will find all the pathogens.
False, you must specify which pathogens you are looking so they can perform specific tests that vary in sensitivity and specificity
True or False: A rectal swab is used to culture for GI pathogens.
False, used to screen for MDROs.
Stool cultures are used to diagnose GI pathogens
What is more infectious: liquid or formed stool
Liquid
But formed stool may also carry pathogens
Why should you not send out urine/water mixed stool?
The test might not be sensitive enough for that diluted sample
What are some MO that cause food poisonings?
Campylobacter jejuni Clostridium botulinum Clostridium perfringens Cronobacter Cyclospora E. coli O157:H7 Hepatitis A and E Listeria monocytogenes Marine Toxins in Bivalve Shellfish Norovirus Salmonella Scombroid Poisoning Shigella Vibrio
What fish can cause scombroid poisoning?
Fish used in sushi (tuna, mackerel, swordfish, marlin, mahi-mahi, sardines) that was not properly stored on ice
What will you notice on the skin of those with scombroid poisining?
Red rash
What predisposes (6) someone to having a GI infection?
1) Diminished secretion of gastric acid
2) Abx (decr. levels of stomach acid)
3) Alcoholism or liver disease (decr. phagocytic and chemotaxis capacity)
4) Lack of long term immunity for viral infections (norovirus)
5) Diminished levels of basic hygiene and increased contact with others
6) Asymptomatic shedders (typhoid)
What can cause diminished secretion of gastric acid?
- Extremes of ages (newborns, elderly)
- Illnesses (pernicious anemia)
- Infections (H pylori)
- Gastric resection, diversion, or removal of vagus nerve
- Anti-ulcer drugs that inhibit gastric acids by blocking H2
What infections do people with diminished gastric acid commonly have?
Salmonella
Virbo cholerae
What are the 7 F routes of transmission for GI?
Fecal oral:
-Feces / Foods / Fluids
Intermediary vehicles:
-Fingers / Flies / Fomites / Fornication
What are complications of GI infections?
- Dehydration **
- Weight loss
- Acute renal failure (E coli 0157)
- Secondary bacterial infections (Shigella, salmonella, typhoid)
- Miscarriage, fetal death
- Septic shock
- Death
What bacteria commonly causes gastritis and ulcers?
Helicobacter pylori (reservoir is humans only!)
How does H pylori cause gastritis and ulcers?
They compete with other bacteria on the gastric epithelium. They have an advantage because of a flagella (swim up the mucosal layer), can adhere to cells and release enzymes (urease) that neutralizes stomach acid to inhibit phagocytosis and cause ulcers.
What bacteria commonly causes enteritis?
Campylobacter jejuni (reservoir is animals)
What bacteria commonly causes diarrhea?
- Vibrio cholera (reservoirs is feces and water)
- Vibrio vulnificus (mollusks, oysters, clams)
What bacteria commonly causes gastroentiritis?
Salmonella sp
What bacteria commonly causes enteric/typhoid fever?
Salmonella typhi (hosts are human only!!!)
What bacteria commonly causes dysentery?
Shigella sp
What bacteria commonly causes hemorrhagic diarrhea or hemolytic uremic syndrome?
E coli 0157:H7 (reservoir cattle –> undercooked hamburgers!)
What complications (5) does E coli 0157:H7 tend to cause?
1) Bloody diarrhea
2) Thrombocytopenia
3) Hemolytic Anemia
4) Acute Renal Failure
5) Hemolytic-uremic syndrome
What causes traveler’s diarrhea?
Enterotoxigenic E coli (produces toxins)
How many types of E coli exist?
5
What abnormal flora do you find in the esophagus?
Candida and herpes
