[Comparative data on the use of high performance liquid chromatography to identify mycobacteria isolated on liquid...

Two hundred and forty-two mycobacterial cultures isolated from clinical materials on the Lwenstein-Jensen solid medium and 208 cultures in the automatic Bactec MGIT 960 system (on the modified Middlebrook 7H9 liquid medium) were examined. Of them, there was M. tuberculosis (85 and 82, respectively), M. kansasii (26 and 24), MAC (46 and 38), M. xenopi (24 and 20), M. fortuitum (26 and 22), and M. chelonae/abscessus complex (20 and 18). Identification of mycobacterial cultures isolated on the solid medium by microbiological assay and high performance liquid chromatography (HPLC) showed the agreement of results of the cultures isolated on the liquid medium in 95.5 and 97.2%, respectively; that by these techniques revealed rapidly growing nontuberculosis mycobacteria in 95.8 and 95.2% of cases, respectively; slowing growing mycobacteria in 91.7 and 97.8%, and M. tuberculosis in 96.5 and 97.6%. Mycobacterial isolation on the Middlebrook 7H9 liquid medium in the automatic Bactec MGIT-960 system takes a shorter time than that on the solid (Lwenstein-Jensen) medium. The microbiological identification of mycobacteria lasts as long as 3 weeks while the use of HPLC reduces its time to 24 hours. The efficiency of HPCL does not depend on whether mycobacterial cultures are isolated on the solid or liquid media.