[Tubercular disease: clinical aspects and drug resistance]

The emergence of multidrug-resistant TB (MDR-TB), and, more recently of extensively drug-resistant TB (XDR-TB) is a real threat to achieve TB control and elimination. Over 500.000 new cases of MDR TB occurred in 2008 worldwide, of whom 50.000 are XDR-TB. A very small fraction of estimated MDR cases are actually diagnosed and notified: hence, the long-term vision for full control of MDR-TB requires, essentially, the scaling-up of culture and DST capacity and the expanded use of high-technology assays for rapid determination of resistance. MDR cases are treatable and well designed regimens, largely based on second-line anti-TB drugs, can considerably improve cure rates. However treatment regimen need to be markedly improved through the introduction of less toxic and more powerful drugs, thus reducing duration of treatment and tolerability. The prevalence of MDR-TB and XDR-TB are inversely correlated with the quality of TB control and the proper use of second line anti-TB drugs. Adherence to proper standards of care and control is imperative and a top priority of all TB control efforts. However, the risk of an un-controllable epidemic of MDR- and XDR-TB is real considering current levels of financing and commitment to care.