In-vitro sensitivities and treatment of less common mycobacteria.

There are very few new agents available for the treatment of infections due to the less common mycobacteria. There have been very few systematic studies of in-vitro activity and fewer clinical trials. Yet such mycobacteria are an important cause of serious disease and often conventional antimycobacterial agents are unsuitable either because of in-vitro resistance of the pathogen concerned, or toxicity of one of the components of drug regimens. At present, newer macrolides and quinolones offer promise, but there is a need to extend the in-vitro studies already under way of newer agents against Mycobacterium avium and/or Mycobacterium tuberculosis, to the other, less common mycobacteria. The benzoxazinorifampicins, the oxazolidinones and the acridinones may prove to be of clinical value. In addition to more information on the in-vitro activity of newer agents, alone and in combination, based on systematic studies involving larger numbers of mycobacterial strains, we need clearer clinical information to enable therapeutic regimens to be formulated and validated. The British Thoracic Society study is but a first step. There need to be more.