Enterobacteriaceae - Shigella

Question 1

Most effective among enteric pathogen

Answer 1

Shigella

Question 2

Which shigella sp is found in developing countries? in the US?

Answer 2

S. dysenteriae

S. sonnei

Question 3

what is shigella similar to

Answer 3

invasive e. coli

Question 4

does shigella ferment lactose?

Answer 4

no

Question 5

Is shigella motile or nonmotile?

Answer 5

nonmotile - no flagella

Question 6

What is the toxin produced by Shigella

Answer 6

Shiga toxin

Question 7

Does shigella have animal reservoir?

Answer 7

no

Question 8

Virulence

shigella

Answer 8

M cells in Peyer’s patches (lymph nodule)
Shiga toxin
uncommon - Bacteremia

Question 9

Mechanism of shiga toxin

Answer 9

AB5
A cleaves the 28S rRNA in the 60S ribosomal subunit.
affects protein synthesis

Question 10

what does plaque assay show

Answer 10

intracellular pathogen (eg shiga toxin effects)

Question 11

What is Reiter’s syndrome?

Answer 11

Autoimmune
arthritis, conjunctivitis, urethritis
after intestinal infections

male - HLA-B27-positive

Question 12

what does methylene blue stain of fecal sample help determine

Answer 12

presence of PMN – could be invasive organisms: Shigella, Salmonella, Campylobacter

Question 13

Transmission of Shigella

Answer 13

only to human
fecal-oral route
no carrier state

Question 14

Two other Enterobacteriaceae that are important:

Answer 14

Klebsiella

Proteus

Question 15

What does Klebsiella pneumonia produce and what does it cause?

Answer 15

produce capsule

Community-acquired or hospital acquired LOBAR pneumonia

Question 16

What does Proteus mirabilis cause? how? what does that lead to? How?

Answer 16

• UTI
• urease
• Kidney stones
• urease – urea –> CO2 and ammonia. rise in pH –> precipitating Mg and Ca2+

Question 17

Clinical manifestation of shigella

Answer 17

Tenesmus, watery first then bloody, mucus diarrhea