I am not a TB expert, so have to review some old medical books & CBC website to answer some of these, but here goes:
The difference between active TB & latent TB: Latent TB basically means that a person has a positive skin test, but no clinical or x-ray signs of the disease. Active TB means that the patient has ongoing disease caused by the TB bacteria, such as a lesion in the lung, bones, neck, etc. This patient has active TB because he has a pulmonary lesion from which the TB has been cultured. See the CDC website for more:
http://www.cdc.gov/tb/faqs/qa_introduction.htm#Intro4
TB is transmitted through the respiratory route. Usually this means inhaling aerosolized droplets from another person who coughed or breathed out the bacteria. This is why patients with active pulmonary TB are placed in respiratory isolation.
According to the CDC: 49 cases of XDR TB from 1993-2006, 17 from 2000-2006.
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5611a3.htm
The only place I saw any speculation about where he caught the TB in was the article below, where it says he travelled to Asia. He certainly could have caught it there as it is much more prevalent in Asia than in the US. Whereever he caught it, it was probably from being exposed to someone who had active pulmonary XDR TB, in close conditions with poor ventilation.
http://www.ajc.com/health/content/health/stories/2007/05/29/0530meshtb.html?imw=Y
This can vary widely. Some people get infected and never develop symptoms of active TB; ie, their TB remains latent. It usually takes at least 2-3 weeks, and sometimes a few months, for the skin test to turn positive.
From these articles:
http://www.ajc.com/health/content/health/stories/2007/05/29/0530meshtb.html?imw=Y
http://www.latimes.com/news/nationworld/nation/la-na-tb1jun01,0,702778.story?coll=la-home-center
http://www.iht.com/articles/2007/05/31/news/health.php
He had a chest X-ray done 1/07 after "chest trauma." The CXR showed an abnormality, which was further evaluated. He had sputum cultures which eventually were positive for TB. The bacteria are notoriously difficult to culture because they grow inside other cells.