Management of Extensively Drug-Resistant Tuberculosis in Peru: Cure Is Possible

Cesar A Bonilla,Ronal B Jamanca,Jaime Bayona,Carole D Mitnick,Aldo Crossa,Alberto Mendoza,Cesar Herrera,Hector O Jave,Matteo Zignol,Ernesto Jaramillo,Luis Asencios,Ben Marais

doi:10.1371/journal.pone.0002957

Abstract

AimTo describe the incidence of extensive drug-resistant tuberculosis (XDR-TB) reported in the Peruvian National multidrug-resistant tuberculosis (MDR-TB) registry over a period of more than ten years and present the treatment outcomes for a cohort of these patients.MethodsFrom the Peruvian MDR-TB registry we extracted all entries that were approved for second-line anti-TB treatment between January 1997 and June of 2007 and that had Drug Susceptibility Test (DST) results indicating resistance to both rifampicin and isoniazid (i.e. MDR-TB) in addition to results for at least one fluoroquinolone and one second-line injectable (amikacin, capreomycin and kanamycin).ResultsOf 1,989 confirmed MDR-TB cases with second-line DSTs, 119(6.0%) XDR-TB cases were detected between January 1997 and June of 2007. Lima and its metropolitan area account for 91% of cases, a distribution statistically similar to that of MDR-TB. A total of 43 XDR-TB cases were included in the cohort analysis, 37 of them received ITR. Of these, 17(46%) were cured, 8(22%) died and 11(30%) either failed or defaulted treatment. Of the 14 XDR-TB patients diagnosed as such before ITR treatment initiation, 10 (71%) were cured and the median conversion time was 2 months.ConclusionIn the Peruvian context, with long experience in treating MDR-TB and low HIV burden, although the overall cure rate was poor, a large proportion of XDR-TB patients can be cured if DST to second-line drugs is performed early and treatment is delivered according to the WHO Guidelines.

Highlights

IntroductionDrug-resistant tuberculosis (XDR-TB) is defined as a disease caused by Mycobacterium tuberculosis isolates resistant to at least isoniazid and rifampicin (which is the definition of multidrugresistant tuberculosis, multidrug-resistant tuberculosis (MDR-TB)) plus to at least one fluoroquinolone and one second-line injectable (capreomycin, kanamycin or amikacin) [1]
Drug-resistant tuberculosis (XDR-TB) is defined as a disease caused by Mycobacterium tuberculosis isolates resistant to at least isoniazid and rifampicin plus to at least one fluoroquinolone and one second-line injectable [1]
A total of 119 XDRTB cases were recorded in the National multidrug-resistant tuberculosis (MDR-TB) registry in the study period, which represent 2.2% of all Drug Susceptibility Test (DST)-confirmed MDRTB cases and 6?0% of the MDR-TB cases who had DST results for at least one fluoroquinolone and one second-line injectable in addition to first-line drugs

Summary

Introduction

Drug-resistant tuberculosis (XDR-TB) is defined as a disease caused by Mycobacterium tuberculosis isolates resistant to at least isoniazid and rifampicin (which is the definition of multidrugresistant tuberculosis, MDR-TB) plus to at least one fluoroquinolone and one second-line injectable (capreomycin, kanamycin or amikacin) [1]. XDR-TB was first introduced as a term in the medical literature in 2006 by a survey of second-line anti-TB drug resistance among MDR-TB isolates collected worldwide [2]. Diagnosing XDR-TB is very challenging as it requires capacity to perform Drug Susceptibility Tests (DSTs) for fluoroquinolones and second-line injectables in addition to first-line anti-TB drugs. DSTs for first-line anti-TB drugs were done nationwide in a quality-assured manner, and second-line anti-TB drugs could only be tested in limited quantity at the Massachusetts State Laboratory Institute (MSLI) in the United States, as part of an international collaboration to implement the so-called DOTSPlus project [9,10,11]

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