The Second Zambian National Tuberculosis Drug Resistance survey - a comparison of conventional and molecular methods

Nathan Kapata, Grace Mbulo, Frank Cobelens, Petra de Haas, Ab Schaap, Pike Mwamba, Winnie Mwanza, Mweemba Muvwimi, Monde Muyoyeta, Maureen Moyo, Lutinala Mulenga, Martin P. Grobusch, Peter Godfrey-Faussett, Helen Ayles

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16 Citations (Scopus)

Abstract

ObjectiveThe prevalence of MDR-TB in Zambia was estimated to be 1.8% in 2001. A second drug resistance survey was conducted in 2008 to determine trends; the use of the Genotype MTBDRplus assay was applied to compare results to the gold standard. MethodA two-stage cluster sampling, with health facilities as primary sampling units. Processed sputum specimens were inoculated on solid media for culture; heat-inactivated bacterial suspensions from sputum samples were tested on a commercial line probe assay for the identification of rifampicin and isoniazid resistance. ResultsA total of 917 patients with TB were enrolled and 883 (96.3%) analysed. A total of 574 (65%) had LJ results and 824 (93.3%) had results from MTBDRplus assay. The median age was 32, and 63.3% were males. MDR-TB according to LJ-based DST was 1.1% (CI 0.1-2.4) whereas according to MDTBDRplus assay was 1.6% (CI 0.6-2.6). Isoniazid monoresistance in new cases was 2.4% (CI 0.613-4.26) based on LJ results and 5.0% (CI 3.2-6.7) based on the MTBDRplus; in retreatment cases, it was 4.4% (CI 0.3-8.6) and 2.40% (CI <0.1-5.1) on LJ and MTBDRplus, respectively. Rifampicin monoresistance in new cases was 0.1% (CI <0.1-0.4) based on LJ and 0.6% (CI 0.01-1.1) based on the MTBDRplus; in retreatment cases, it was 0% (CI 0-3.8) and 1.8% (CI <0.1-4.0) on LJ and MTBDRplus, respectively. There were no XDR-TB cases found and no association between MDR-TB and HIV. ConclusionThere was no increase in MDR-TB prevalence in Zambia from 2001 to 2008; results from the two methods were similar. Molecular methods were quicker and simpler to use
Original languageEnglish
Pages (from-to)1492-1500
JournalTropical Medicine & International Health
Volume20
Issue number11
DOIs
Publication statusPublished - 2015

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