DETECTION OF MYCOBACTERIA IN BONE-MARROW BIOPSY SPECIMENS TAKEN TO INVESTIGATE PYREXIA OF UNKNOWN ORIGIN

Aims-To investigate the value of bone marrow biopsy in the diagnosis o f mycobacterial infection. Methods-The culture results of 433 bone mar row samples taken between 1983 and 1992 were reviewed. The histopathol ogy reports on bone marrow trephine specimens of culture positive samp les and all those on HIV positive patients sent in 1992 were also revi ewed. Results-Fifty one specimens yielded Mycobacterium spp, 47 were o btained from HIV positive patients. Of the isolates, 42 were Mycobacte rium avium-intra-celluare (MAI), five were M tuberculosis (MTB), and t he remaining four comprised a variety of atypical mycobacteria. All MA I positive samples were obtained from HIV positive patients, with the bone marrow being the only culture positive specimen in one third. Bon e marrow yielded MTB only in patients from whom it was also isolated i n other specimens. Eleven of 47 trephine specimens from positive bone marrow showed granulomata and nine showed acid-fast bacilli. No acid-f ast bacilli were seen in the absence of granulomata. Conclusion-Bone m arrow biopsy for mycobacterial culture should be reserved for severely immunosuppressed patients and should not be advocated for immunocompe tent patients with suspected tuberculosis. Bone marrow biopsy still ha s a role in the investigation of pyrexia of unknown origin in HIV posi tive patients, despite the advent of mycobacterial blood culture techn iques, particularly if these can be processed safely in automated syst ems.