Table 2.

Detection of mycobacteria according to initial smear results in the BACTEC 460 TB and MGIT 960 systems

Species and smear resultTotal no.No. of isolates (% of total) recovered ind:Pf
M. tuberculosiscomplex5753 (93.0)51 (89.5)NS
 Positive1717 (100.0)16a (94.1)NS
 Negative4036b (90.0)35b (87.5)NS
M. avium-M. intracellulare 3836 (94.7)32 (84.2)NS
 Positive1111 (100.0)8b (72.7)NS
 Negative2725b (92.6)24b (88.9)NS
Other mycobacteria3227 (84.4)16 (50.0)0.003
 Positive33 (100.0)3 (100.0)ND
 Negative2924b (82.8)13c (44.8)0.003
All mycobacteriae 123112 (91.1)96 (78.0)0.005
 Positive3030 (100.0)26 (86.7)NS
 Negative9382 (88.2)70 (75.3)0.023
  • a Lost due to contamination (other samples of patient positive).

  • b No growth indicated.

  • c Three lost due to contamination; no growth indicated for 13.

  • d Abbreviations: 460, BACTEC 460TB system; 960, BACTEC MGIT 960 system.

  • e “All mycobacteria” is not equal to the sum of mycobacterial groups, as some samples had two mycobacterial species.

  • f For comparison of BACTEC systems. Abbreviations: NS, not significant; ND, not done.