Resistance to second-line injectables and treatment outcomes in multidrug-resistant and extensively drug-resistant tuberculosis cases

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Extensively drug-resistant tuberculosis is worse than multidrug-resistant tuberculosis: different methodology and settings, same results.

11siThe article by Kim et al. about the impact of extensively drug-resistant (XDR) tuberculosis (TB) on treatment outcomes of non–HIV-infected patients affected by multidrug-resistant (MDR) TB. Kim et al. found, with univariate analysis, that patients with XDR TB had a borderlinesignificant higher probability of treatment failure and death than did patients with MDR TB. Multivariate analysis confirmed that XDR TB is a poor independent prognostic factor for treatment failure. Two studies from our group had previously reached similar conclusions. Our first study found that patients with XDR TB in Italy and Germany, compared with patients with MDR TB, had a 5-fold increase in the risk of death (relative risk, 5.45; 95% CI, 1.95–15.27; P ! .01), required longer hospitalization, had longer treatment duration, and, for the few patients whose sputum and smear converted from positive to negative, a longer time to smear or culture conversion. The second study found that patients with XDR TB had a relative risk of 1.58 to die or have treatment failure, compared with patients with MDR TB resistant to all first-line drugs , and a relative risk of 2.61, compared with patients with MDR TB for whom susceptibility to _1 first-line drug still existed. Interestingly, the results of the studies from the 2 groups are consistent, although the definitions used were slightly different: Migliori et al. used theWorld Health Organization definitions of treatment success and failure, and Kim et al. applied the definitions proposed by Laserson et al.nonemixedMIGLIORI GB; LANGE C; GIRARDI E; CENTIS R; BESOZZI G; KLIIMAN K; ORTMANN J; MATTEELLI A; SPANEVELLO A; CIRILLO DM; SMIRATBNET STUDY GROUPMigliori, Gb; Lange, C; Girardi, E; Centis, R; Besozzi, G; Kliiman, K; Ortmann, J; Matteelli, A; Spanevello, Antonio; Cirillo, Dm; SMIRATBNET STUDY, Grou

Resistance to second-line injectables and treatment outcomes in multidrug-resistant and extensively drug-resistant tuberculosis cases.

No information is currently available on the influence of injectable second-line drugs on treatment outcomes of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) patients. To investigate this issue, a large series of MDR- and XDR-TB cases diagnosed in Estonia, Germany, Italy and the Russian Federation (Archangels Oblast) between 1999 and 2006 were analysed. All study sites performed drug susceptibility testing for first- and second-line anti-TB drugs, laboratory quality assurance and treatment delivery according to World Health Organization recommendations. Out of 4,583 culture-confirmed cases, 240 MDR- and 48 XDR-TB cases had a definitive outcome recorded (treatment success, death, failure). Among MDR- and XDR-TB cases, capreomycin resistance yielded a higher proportion of failure and death than capreomycin-susceptible cases. Resistance to capreomycin was independently associated with unfavourable outcome (logistic regression analysis: odds ratio 3.51). In the treatment of patients with multidrug-resistant and extensively drug-resistant tuberculosis, resistance to the injectable drug capreomycin was an independent predictor for therapy failure in this cohort. As Mycobacterium tuberculosis drug resistance is increasing worldwide, there is an urgent need for novel interventions in the fight against tuberculosis