Flashcards in Micro - Systems (Normal Flora & GI) Deck (42):
What is the dominant microorganism in the normal flora of the skin?
What is the dominant microorganism in the normal flora of the nose? What other major microorganism colonizes the nose?
S. epidermidis; colonized by S. aureus
What is the dominant microorganism in the normal flora of the oropharynx?
Viridans group streptococi
What is the dominant microorganism in the normal flora of the dental plaque?
What are 2 dominant microorganism in the normal flora of the colon? Which is more dominant?
B. fragilis > E. coli
What is the dominant microorganism in the normal flora of the vagina? What other 2 microorganisms colonize the vagina?
Lactobacillus, colonized by E. coli and group B strep
What kind of flora do neonates delivered by C-section have, and how does this change over time?
Neonates delivered by C-section have no flora but are rapidly colonized after birth
Which 2 bugs cause food poisoning that starts quickly and ends quickly?
S. aureus and B. cereus food poisoning starts quickly and ends quickly
Name 7 bugs that cause food poisoning.
(1) B. cereus (2) C. botulinum (3) C. perfringens (4) E. coli O157:H7 (5) Salmonella (6) S. aureus (7) V. parahaemolyticus and V. vulnificus
What is the source of infection for B. cereus food poisoning?
Reheated rice; Think: "Food poisoning from reheated rice? Be serious!" (B. cereus)
What is the source of infection for C. botulinum food poisoning?
Improperly canned foods (sign is bulging cans)
What is the source of infection for C. perfringens food poisoning?
Reheated meat dishes
What is the source of infection for E. coli O157:H7 food poisoning?
What is the source of infection for Salmonella food poisoning?
Poultry, meat, and eggs
What is the source of infection for S. aureus food poisoning?
Meats, mayonnaise, custard; preformed toxin
What is the source of infection for V. parahaemolyticus and V. vulnificus food poisoning?
Besides food poisoning, what else can V. vulnificus cause?
V. vulnificus can also cause wound infections from contact with contaminated water or shellfish
Name 7 bugs that cause bloody diarrhea.
(1) Campylobacter (2) E. histolytica (3) Enterohemorrhagic E. coli (4) Enteroinvasive E. coli (5) Salmonella (6) Shigella (7) Y. enterocolitica
What is the morphology of Campylobacter? In what conditions do they grow?
Comma- or S-shaped organisms; growth at 42 C
What kind of organism is E. histolytica? What is the main condition that it causes? What other physical/imaging finding is common?
Protozoan; Amebic dysentery; Liver abscess
What is the main strain of Enterohemorrhagic E. coli (EHEC) associated with bloody diarrhea? What condition can EHEC cause? What toxin does it make?
O157:H7; Can cause HUS; Makes Shiga-like toxin
How does enteroinvasive E. coli cause bloody diarrhea?
Invades colonic mucosa
Does either Salmonella or Shigella ferment lactose?
No, both are lactose (-)
Does Salmonella or Shigella have flagella motility?
What kind of reservoir does Salmonella have? What are 2 especially common sources of infection?
Has animal reservoir, especially poultry and eggs
What kind of infective dose dose shigella have?
Very low ID50 (i.e., median infective dose)
What kind of toxin does Shigella produce? What kind of reservoir does it have?
Produces Shiga toxin (human reservoir only)
Other than bloody diarrhea, what condition can Shigella cause?
In what setting do Y. enterocolitica outbreaks typically occur?
With what condition is Y. enterocolitica associated?
Name 6 bugs that cause watery diarrhea.
(1) C. difficile (2) C. perfringens (3) Enterotoxigenic E. coli (4) Protozoa (5) V. cholerae (6) Viruses
Other than diarrhea, what condition does C. difficile cause?
What kind of diarrhea can C. difficile cause?
Watery diarrhea, Occasionally bloody diarrhea
What causes C. difficile?
Caused by antibiotics
Besides watery diarrhea, what other major symptom/condition does C. perfringens also cause?
Also causes gas gangrene
What organism is associated with Traveler's diarrhea?
Enterotoxigenic E. coli
What kind of toxins does Enterotoxigenic E. coli produce?
Produces heat-labile (LT) and heat-stable (ST) toxins
What are the 2 protozoa that can cause watery diarrhea? Which targets the immunocompromised?
(1) Giardia (2) Cryptosporidium (in immunocompromised)
What is the morphology of V. cholerae?
Describe the diarrhea caused by V. cholerae.
What is often a source of V. cholerae?
Often from infected seafood