Predictive value of direct nitrate reductase assay and its clinical performance in the detection of multi and extensively drug resistant tuberculosis.

IMPERIALE B; MORCILLO N; J C PALOMINO; VANDAMME P; MARTIN A

JOURNAL OF MEDICAL MICROBIOLOGY

SOC GENERAL MICROBIOLOGY

Lugar: London; Año: 2014 p. 522 - 527

0022-2615

Conventional culture and drug susceptibility testing (DST) methods for27 Mycobacterium tuberculosis are laborious and time consuming. For this reason28 alternative rapid culture and DST techniques are urgently needed to shorten the time29 for drug-resistance detection. A total of 222 smear-positive sputum samples were30 evaluated by the direct nitrate reductase assay (D-NRA) on Lowenstein-Jensen31 medium, for the rapid and simultaneous detection of resistance to isoniazid (INH),32 rifampicin (RIF), kanamycin (KAN) and ofloxacin (OFL). The p-nitrobenzoic acid was33 also included for identification of the M. tuberculosis complex. Results were34 compared with the BACTEC MGIT 960 as gold standard. The general performance35 of the D-NRA was very good reaching a global value of 97%. D-NRA showed a turn36 around time of 16.9 days to obtain results while that of the indirect MGIT 960 system37 was 29 days. D-NRA is a low-cost technology, easy to set up in clinical laboratories38 and suitable to be used for DST of M. tuberculosis in all smear-positive samples