Sputum from a patient with a history of tuberculosis due to Mycobacterium tuberculosis bacteria is collected and sent to the microbiology lab for analysis. X-ray analysis and an acid-fast smear made from the sputum indicate that the patient has active tuberculosis. The physician has requested that the sputum be analyzed for pathogen load, but because colonies of Mycobacterium typically take between 3 to 8 weeks to appear on agar, results from traditional culture methods are often delayed. If you were the microbiologist in this case, what would you do?

Question

A. Using the sputum, apply end-point PCR with primers to Mycobacterium tuberculosis DNA to estimate the pathogen load, then follow up with a traditional culture.
B. Set up a traditional culture on the sputum, then use the colonies for real-time PCR with primers to Mycobacterium tuberculosis DNA to quantify the pathogen load.
C. Set up a traditional culture on the sputum, then use the colonies for end-point PCR with primers to Mycobacterium tuberculosis DNA to quantify the pathogen load.
D. Using the sputum, apply real-time PCR with primers to Mycobacterium tuberculosis DNA to estimate the pathogen load, then follow up with a traditional culture. 

Answer 1

Answer: D