BACTERIOPHAGE TYPES OF MYCOBACTERIUM-TUBERCULOSIS IN THE UNITED-STATES

Abstract

Strains of M. tuberculosis from various geographic areas within the continental USA were typed according to their susceptibility to 4 mycobacteriophages. Of 462 wild isolates studied, 34% were phage type 1 (previously designated Ao), 42% were type 2 (A1), 2.6% were type 5 (A4), 1.3% were type 7 (A6) and 20.1% were type 8 (B). Distribution of types was essentially unaffected by geographic location, sex, age or ethnic origin of the patient or by resistance of the isolate to antituberculosis drugs. Major types were further divided by susceptibility of the strains to lysis by 8 auxillary phages, 2 of which were phages newly evaluated in this study. A new numbering system is proposed for designating major phage types of M. tuberculosis.