Prospective multicentre evaluation of the direct nitrate reductase assay for the rapid detection of extensively drug-resistant tuberculosis

MARTIN A; IMPERIALE B; RAVOLONANDRIANA P; YILMAZ COBAN A; AKGUNES A; IKRAM A; SATTI L; ODOUN M; PANDEY P; MISHRA M; AFFOLABI D; SINGH U; RASOLOFO V; MORCILLO N; VANDAMME P; PALOMINO JC

JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2013 p. 1 - 4

0305-7453

Objectives: To perform a multicentre study evaluating the performance of the direct nitrate reductase assay (NRA) for the detection ofmultidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis in sputumsamples. Methods: The studywas conducted in six laboratories performing tuberculosis diagnosis thatwere located in six different countries. The NRAwas performed directly on sputum samples in parallel with the reference method used at each site. Detection of resistance was performed for rifampicin, isoniazid, ofloxacin and kanamycin. Results: Excellent agreement was obtained for all drugs tested at the majority of sites. The accuracy was 93.7%? 100%for rifampicin, 88.2%?100%for isoniazid, 94.6%?100%for ofloxacin and 100%for kanamycin. The majority of NRA resultswere available at day 21 for sites 1, 2 and 5. Site 3 had a turnaround timeof 13.9 days, at site 4 itwas 18.4 days and at site 6 it was 16.2 days. The contamination rate ranged between 2.5% and 12%. Conclusions: Rapid detection of drug resistance by the direct NRA on sputumsmear-positive samples was accurate andeasy toimplement in clinical diagnostic laboratories,makingita goodalternative for rapidscreeningforMDRand XDR tuberculosis.