Micro 7 - Diarrhea Flashcards
What are the four types of Escherichia coli?
- Enterotoxigenic E. coli (ETEC) 2. Enterohemorrhagic E. coli (EHEC) 3. Enteropathogenic E. coli (EPEC) 4. Enteroinvasive E. coli (EIEC)
Describe Enterotoxigenic E. coli (ETEC).
- Water diarrhea due to heat-liable and heat stable enterotoxins. 2. Does not infect the intestinal wall 3. Most common type of traveler’s diarrhea.
Describe enterohemorrhagic E. coli (EHEC).
- Bloody diarrhea and severe illness from infected meat. 2. Most common is 0157:H7 3. Produces shiga-like toxins. 4. Can lead to hemolytic uremic syndrome (HUS): anemia, thrombocytopenia, acute renal failure. Treatment: supportive.
Describe Enteropathogenic E. coli (EPEC).
- Watery diarrhea, but not toxin produced. 2. Common in children.
Describe Enteroinvasive E. coli.
- Bloody diarrhea and fever due to intestinal wall invasion. 2. Closely related to Shigella.
What is the treatment for Enteroinvasive E. coli (EIEC)?
Fluoroquinolones, TMP-SMX, azithromycin.
Describe clinical features of Shigella.
- Causes watery diarrhea that turns to bloody diarrhea by invading the intestinal mucosa, causing inflammation and necrosis. Causes mucus and fever. 2. Produces Shiga toxins as well. 3. Lasts for 1-2 weeks. 4. It is a non-lactose fermenter.
How is Shigella spread?
- Person to person contact. 2. Contaminated food and water.
How does Shigella differ from Salmonella in terms of their anatomical structure?
Shigella does not have flagella. Salmonella does.
What is the treatment for Shigella?
Suppurative. In severe cases: Fluoroquinolones = 1st line. TMP-SMX or azithromycin = 2nd line or pediatrics.
Which bacteria infections are related to cause Reiter syndrome?
- Shigella flexneri 2. Salmonella
What is the clinical presentation of Salmonella?
- Bloody diarrhea and fever that begins 1-3 days later. 2. Non-lactose fermenter 3. Picnic setting, egg salad or chicken salad. 4. Turtles, pet stores.
How is salmonella diagnosed?
Stool culture.
What is the treatment for salmonella?
Healthy adults need only supportive care. In intense cases, fluoroquinolones = 1st line.
What is the bacteria that needs to be suspected in osteomyelitis in sickle cell patients?
Salmonella due to having flagella that gives them ability to spread hematogenously.
What is classic clinical presentation of Salmonella typhi?
“Rose spots” on the abdomen.
Describe campylobacter jejuni.
- G(-) 2. Z-shaped 3. Oxidase positive 4. Bloody diarrhea, especially in children 5. Grows in at 42C [Campylobacter likes it hot like a camp fire] 6. Self-limited but can last for 1-2 weeks.
How is Campylobacter jejuni transmitted?
Fecal-oral; poultry, meat, unpasteurized milk.
Which disease is campylobacter jejuni associated with?
Guillain-Barre syndrome.
Describe Vibrio cholerae.
- G(-) 2. Oxidase positive bacilli 3. Watery diarrhea “Rice-water”- Causes profound diarrhea. 4. Flagellum 5. Grows in alkaline media
What does the toxin of Vibrio cholerae do?
Permanently activates cAMP.
What is the treatment for Vibrio cholerae?
Aggressive oral rehydration.
What disease can Yersinia enterocolitica cause that can mimic appendicitis?
Mesenteric adenitis
How is Yersinia enterocolitica spread?
From undercooked pork and milk and hosehold pets.
Describe Klebsiella pneumoniae.
- G(-) 2. Lactose fermenting 3. Normal intestinal flora 4. Affects people with weakened immune systems: alcoholics, dibatics, chronic illness.
What pathologies does Klebsiella pneumoniae cause?
- Lobar pneumonia 2. Red currant jelly sputum 3. Necrosis in the lungs 4. Major cause of UTIs
Describe Clostridium difficile.
- Gram (+) 2. Oxidase negative 3. Spore-forming bacilli 4. Produces Toxin A and Toxin B.
What does Toxin A of C. difficile cause?
AKA enterotoxin, binds to the brush border of the gut, leads to intestinal fluid secretion and inflammation.
What does Toxin B of C. difficile cause?
Kills enterocytes by targeting the cytoskeletal structures of the enterocytes. Causes pseudomembranous colitis.
Describe pseudomembranous colitis and primary risk factor.
Necrosis with exudates, fibrin and leukocytes of the colon caused by overgrowth of C. difficile. Primary risk factor is antibiotic use, especially cindamycin and ampicillin.
How do we test for Pseudomembranous colitis?
C. diff toxin in the stool.
How do we test pseudomembranous colitis?
- Metronidazole 2. Vancomycin (orally).
Why do we use vancomycin orally instead of the usual IV way in pseudomembranous colitis?
Because when taken orally, it is not absorbed systematically; its stays on the gut, hoping to control C. diff. This is why it also will not cause nephrotoxicity as it usually does.
What foods are associated with Staph aureus?
Meats, mayonnaise, potato salad, and custard.
Why does Staph aureus produce rapid onset of symptoms when ingested?
Preformed toxin.
What bacteria is associated with reheated rice?
Bacillus cereus.
What bacteria is associated with shellfish?
Vibrio parahaemolyticus and vulnificus.
What food is associated with Clostridium botulinum?
Improperly canned foods.
What bacteria is associated with clostridium perfringens?
Reheated meat disehes.
What bacteria is associated with undercooked contaminated hamburger meat?
E. coli O157:H7
Which form of E. coli causes hemolytic-uremic syndrome (HUS)?
E. coli O157:H7
Which bacteria is associated with food poisoning as a result of mayonnaise sitting out for too long?
Staph aureus
Which bacteria is associated with diarrhea caused by G(-) nonmotile organism that does not ferment lactose?
Shigella
Which bacteria is associated with rice-water stools?
Vibrio cholerae Could potentially be Enterotoxigenic E. coli.
Which bacteria is associated with diarrhea caused by S-shaped organism?
Campylobacter
Which bacteria is associated with diarrhea transmitted from household pets?
Yersinia enterocolitica
Which bacteria is associated with food poisoning resulting from reheated rice?
Bacillus cereus
Which bacteria is associated with diarrhea caused by G(-) motile organism that does not ferment lactose?
Salmonella.
Which bacteria is associated with the most common cause of traveler’s diarrhea?
ETEC
Which bacteria is associated with diarrhea after a course of antibiotics?
Clostridium difficile
Which bacteria is associated with food poisoning due to exotoxin?
S. aureus and Bacillus cereus
Which bacteria is associated with osteomyelitis in sickle cell disease?
Salmonella.
