Enteric Bacteria Flashcards
What are major food borne enteric bacteria?
Shigella, E. coli, and Salmonella
What are the general defining characteristics of enteric bacteria?
Gram - No spores Straight rods Facultative anaerobes Catalase + Oxidase - Glucose fermentors
How likely are enteric bacteria to acquire new DNA?
Very promiscuous
What are virulence factors common to enteric bacteria?
Pili, T3SS, Antibiotics resistnace
How are food borne enterobacteriaceae acquired?
They are acquired by contaminated food
What is a common symtom of salmonella, Yersinia and some E. coli?
watery diarrhea
What is the infectious dose of salmonella?
Very high
What is the treatment for a foodborne acquired enterobacteriaceae?
Usually none because they are self limited
What is the mechanism of T3SS?
alter the gut macrophage and help the bacteria evade immune sampling. they make the macrophage apoptose. bacteria can then infect the exterior surface of the intestines
What cells does the T3SS help the bacteria evade?
M cells of Peyer’s patches in the gut
How do enteric bacteria use macrophages?
Use the macrophage to reach the lymph nodes and establish infections in all the lymph nodes
What is the systemic infection that salmonella causes when it uses macrophages as trojan horses?
Typhoid fever
What organ can S. typhi establish chronic infection?
gall bladder
What are possible complications of Shigella and E. coli
HUS
How does HUS happen?
the bacteria breaches the gut and releases a shiga toxin into the blood stream
What are the effects of the shiga toxin?
Hemolysis
Thrombocytopenia
uremia
What are the symptoms are reactive arthritis?
conjunctivitis, arethritis, arthritis
What agents can cause reactive arthritis?
shigella, salmonella. yersinia, campylobacter, chlamydia
What type of patients are most likely to have reactive arthritis triggered?
HLA- B27 positive
Give an example of an ICU bug
Klebsiella pneumoniae
What are the predisposing conditions to a Klebsiella infection?
Advanced age, chronic respiratory disease, diabetes, alcoholism
What is the major virulence factor for klebsiella pneumonia?
Capsule that prevents against phagocytosis
How does a K. pneuomia infection present?
lobar pneumonia with necrosis, inflammation and hemorrhage
What is key in treating these ICU bugs?
sensitivity testing for antibiotics
