Treatment Challenges: Multidrug-Resistant Tuberculosis and Atypical Mycobacteria Infections

摘要

Resistance to antituberculosis drugs is indeed a worldwide phenomenon.1 Currently, the median prevalence rates of multidrug-resistant tuberculosis (MDR-TB), with bacillary resistance to isoniazid and ri-fampicin in vitro at least, are about 1.0% (new cases), 9.3% (previously treated cases) and 1.8% (combined).1 Hot spots of MDR-TB are present in virtually all continents. The prevalence of drug resistance in a community generally varies directly with the proportion of cases with previous treatment but inversely with the proportion of cases under directly observed therapy, short course (DOTS). Thus, DOTS is the best way to prevent development of MDR-TB.2 The use of fixed dose combination formulations also decreases the risk of developing MDR-TB.3 Employment of long-acting rifamycin such as rifapentine can potentially facilitate the delivery of DOT and enhances adherence.4 Notwithstanding rather encouraging preliminary results, further exploration of the optimum dosage of this rifamycin to achieve a lower failure / relapse rate is still required. This drug is apparently not suitable for patients with certain disease characteristics such as HIV seropositivity.5