Self learning guiding questions for the three Yersinias (pestis, enterocolitica, pseudotuberculosis).  See Chapters 9, 17, 57, 62, 73, 76 in Schaecter to answer these questions.  Note also that simply completing this exercise is instructive in itself.  According to the FDA, there is little, if any, Y. pseudotuberculosis in the U.S., so Y. enterocolitica is the major foodborne concern.

1.  In terms of encounter, what do the three Yersinias have in common?
   A.  All are most commonly encountered through ingestion.
   B.  All are most commonly encountered through inhalation.
   C.  All are most commonly encountered through animal bites.
   D.  All are most commonly encountered through arthropod bites.
   E.  All have animal reservoirs.

2.  In terms of diseases caused, which two are most similar?
   A.  pestis and pseudotuberculosis
   B.  pestis and enterocolitica
   C.  enterocolitica and pseudotuberculosis
   D.  they are all completely different

3.  To which capsule is the pestis capsule most similar?
   A.  Streptococcus pneumoniae
   B.  Bacillus anthracis
   C.  Neisseria meningitidis type B
   D.  Haemophilus influenzae type b
   E.  Enterotoxinigenic E. coli (ETEC)

4.  What is the type III secretion system of these yersinias used for?
   A.  Invasion of epithelial cells.
   B.  Preventing phagocytosis by macrophages
   C.  Stimulating cAMP production
   D.  Stimulating diarrhea
   E.  Preventing phagosome-lysosome fusion

5.  Which yersinia is known to be a hazard for blood supplies and why?
   A.  enterocolitica because it can thrive in cold temperatures.
   B.  pseudotuberculosis because it mimics blood group antigens
   C.  pestis because people with bubonic plague have high levels of bacteremia

6.  What gene production of pestis facilitates spread through tissues?
   A.  hyaluronidase
   B.  protease
   C.  lipase
   D.  plasminogen activator
   E.  fibrinogen activator