How do people get multidrug-resistant tuberculosis?

Multidrug-resistance tuberculosis (MDR-TB) is defined as resistance to the two most important TB antibiotics – isoniazid and rifampicin. It is difficult to treat and patient outcomes are much worse. MDR-TB rates are rising as drug-susceptible TB rates are falling. It remains unclear why. 

I plan to investigate whether people get MDR-TB from other infected patients or whether drug-resistance more commonly evolves after people are exposed to antibiotics. I will determine the DNA sequence of all MDR-TB strains in Ho Chi Minh City, Vietnam, and build a family tree from these data to determine which strains are related through transmission. I will also focus on patients who are not cured by antibiotics or get disease a second time, asking whether their treatment failed because they were given too few effective antibiotics, or the wrong dose of antibiotics and whether this led to resistance.

My findings will add to our knowledge of the mechanisms behind multidrug resistance and help in the development of more effective treatments for tuberculosis.