TABLE 1.

Performance of the optimized assay with primary drug-susceptible and -resistant respiratory and nonrespiratory specimens

Smear resultaM. tuberculosis culture resultbSDA resultbNo. of specimens with interpretable DNA strip reading results/no. of tested specimens (%)
RIF and INH susceptibledRIF and/or INH resistantd
RespiratoryNonrespiratoryRespiratoryNonrespiratory
4++NDc7/71/14/41/1
3++ND4/44/47/72/3 f
2++ND6/62/24/43/3
1++ND3/52/31/10/1
+ND2/61/20/82/6
++0/51/3
+0/10/3
+2/6 e0/2
0/60/2
All positive20/22 (91)9/10 (90)16/16 (100)6/8 (75)
All negative4/24 (17)2/12 (17)0/8 (0)2/6 (33)
Total24/46 (52)11/22 (50)16/24 (67)8/14 (57)
  • a Smear grading for acid-fast bacilli was done according to an international standard. −, negative result.

  • b +, positive result; −, negative result.

  • c ND, not done.

  • d By BACTEC 460.

  • e Interpretable DNA strip reading with a culture-negative, SDA-positive sample, probably due to the presence of nonviable bacteria.

  • f One sample (gastric lavage fluid) failed to give an interpretable DNA strip result, as the M. tuberculosis complex-specific control (23S rRNA) was lacking.