Identification of mycobacteria by mycolic acid pattern

Background: Tuberculosis caused by Mycobacterium tuberculosis is a public h ealth problem which has increased in importance during the last 12 years, d ue in part to the increasing number of cases caused by the association of a cquired immunodeficiency syndrome (AIDS) and the appearance of multiple dru g-resistant strains. Other mycobacteria which are often indistinguishable f rom tuberculosis have also increased. Methods: Mycolic acid patterns were obtained from 53 clinical isolates of s putum, cerebrospinal fluid, bronchial washing, corneal ulcer, and bone marr ow, as well as from 11 acid-fast stain smear-positive clinical specimens. S tandardized mycolic acid extraction method was used to ensure the maximal e xtraction of mycolic acid derivatives to enhance the sensitivity of the met hod. A chromatographic column different from what others have employed and a different gradient elution from those reported in the literature were use d, making a correlation between retention times for the chromatographic pea ks obtained in this study and those previously reported for mycolic acid pa tterns from a strain of Mycobacterium avium necessary. Then, a comparison o f retention times of mycolic acid pattern obtained in this study and those previously reported in the literature was carried out. Strains were identif ied as Mycobacterium tuberculosis complex,Mycobacterium avium complex, Myco bacterium fortuitum, Mycobacterium chelonae and Mycobacterium kansasii in l ess than 24 hours. Results: In direct analysis of acid-fast stain smear-positive from 1+ to 4 specimens, mycolic acid patterns were identified as Mycobacterium tubercul osis complex, Mycobacterium avium complex, Mycobacterium chelonae, and Myco bacterium kansasii, with a strong signal even in light 1+ positive samples. Conclusions: The results showed that identification of mycobacteria through mycolic acid pattern is a rapid, sensitive, and very useful method for ide ntification of mycobacteria in the early diagnosis of the mycobacteriosis.