Media and methods for phage-typing mycobacteria

Media widely used for primary isolation, for drug-sensitivity tests and for type differentiation of mycobacteria have been tested for use in phage studies on the tubercle bacilli. Modifications of each of these media provided some improvement in phage activity on some strains of mycobacteria but not on others. During these studies it was observed that certain substances augmented phage activity, while other substances were found to have the opposite effect. On the basis of these results, a new medium has been formulated. This medium can be used without agar as a liquid medium for growth of the mycobacteria or with agar as a solid medium for isolated plaques and routine test dilution (RTD) spots. An outline of a pilot phage-typing test on three species of Mycobacterium is included.