Describe the use of a DNA probe and PCR for rapid identification of an unknown bacterium

Answer Critical Thinking Question 2 for Chapter 10 on page 297
Describe the use of a DNA probe and PCR for:
a) Rapid identification of an unknown bacterium.
b) Determining which of a group of bacteria are most closely related
Clinical Application question 3 for chapter 11 on page 329
A Woman complaining of lower abdominal pain with a temperature of 39 degree C gave birth soon after to a stillborn baby. Blood cultures from the infant revealed gram-positive rods. The woman had a history of eating unheated hot dogs during her pregnancy. Which organism is most likely involved