Bacterial Gastroenteritis (Exam #3) Flashcards
What type of agar is used to diagnose Enterobacteriaceae (Bacterial Gastroenteritis)?
MacConkey agar
What results are seen on MacConkey agar for Salmonella?
Lac-
H2S+
What results are seen on MacConkey agar for E. coli?
Lac+
H2S-
What results are seen on MacConkey agar for Shigella?
Lac-
H2S-
What three VF are seen with almost all Enterobacteriaceae (Bacterial Gastroenteritis)?
- Flagella (H antigen)
- Capsule (K and Vi antigens)
- LPS (O antigen)
Are Enterobacteriaceae (Bacterial Gastroenteritis) G- or G+?
G-
What VF allows for the transfer of bacterial proteins to the host cells?
T3SS
What is the general transmission for the three Enterobacteriaceae (Bacterial Gastroenteritis)?
Fecal-oral transmission via contaminated food/water
Of the three Enterobacteriaceae (Bacterial Gastroenteritis), which is NOT transmitted via person-to-person contact? Which need LOW vs HIGH infectious doses?
HIGH infectious dose = Salmonella enterica
- NOT spread person-to-person because of this
LOW infectious dose = E. coli and Shigella = spread person-to-person
What is the recommended treatment for Enterobacteriaceae (Bacterial Gastroenteritis)? What treatment is NOT recommended, and what would be the exception to this?
Supportive care
- NO abx unless immunocompromised
What can be a complication of abx use with Enterobacteriaceae (Bacterial Gastroenteritis)?
DHUS = diarrhetic hemolytic uremic syndrome
By what two VF is Salmonella enterica serotyped by?
- Flagella (H antigen)
- LPS (O antigen)
Based on serovars of Salmonella enterica, which two do NOT cause Bacterial Gastroenteritis?
No Typhi or Paratyphi = cause Bacterial Gastroenteritis
What organism involves the VF of SPI1 T3SS?
Salmonella enterica
- Bacterial Gastroenteritis
Which Enterobacteriaceae (Bacterial Gastroenteritis) can present systemically as bacteremia?
Salmonella enterica
What are the three types of E. coli that cause Bacterial Gastroenteritis?
- Enterotoxic E. coli (ETEC)
- Enterohemorrhagic E. coli (EHEC)
- Enteroinvasive E. coli (EIEC)
Which of the three types of E. coli (Bacterial Gastroenteritis) is common in developing countries and travelers?
Enterotoxic E. coli (ETEC)
Which organism involves VF of LT1 and STb? What are these two VF, and what is an important characteristic of each?
Enterotoxic E. coli (ETEC)
- LT1 = heat labile toxin
- STb = heat stable toxin
With LT1 and STb of Enterotoxic E. coli (ETEC), what substance does each cause an increase in?
- LT1 = increased cAMP
- STb = increased cGMP
With LT1 of Enterotoxic E. coli (ETEC), what toxin is it similar to?
LT1 is similar to Cholera AB toxin
What is another name for Enterohemorrhagic E. coli (EHEC)?
STEC = Shiga Toxin-producing E. Coli
What is the most common serotype of Enterohemorrhagic E. coli (EHEC)?
O157:H7
What four VF are associated with Enterohemorrhagic E. coli (EHEC)? What is a characteristics/important note for each?
- Shiga-like toxin (binds human receptor)
- AB toxin (stops protein synthesis)
- Intimin (allows for adhesion
- Tir T3SS (acts as Intimin receptor)
What organism is associated with Shiga-LIKE toxin?
Enterohemorrhagic E. coli (EHEC)