because extensively drug-resistant (xdr) tuberculosis is resistant to the most powerful first-line and second-line drugs patients are left with treatment options that are much less effective and often have worse treatment outcomes. xdr is of special concern for people with hiv infection or other conditions that can weaken the immune system. these people are more likely to develop tb disease once they are infected and also have a higher risk of death once they develop tb disease.
why is extensively drug-resistant (xdr) tuberculosis so serious?