Phage typing of the Mycobacterium avium-intracellulare-scrofulaceum complex. A study of strains of diverse geographic and host origin.

A total of 339 strains of the Mycobacterium avium-intracellulare-scrofulaceum complex were phage typed using our previously described technique and 11 typing phages. These included 235 strains of human origin obtained from state health laboratories in Virginia, Georgia, Florida, and Arkansas, 26 strains isolated from persons with AIDS, 38 strains isolated from animals, and 40 environmental isolates. A phage-typing scheme was developed that denotes sensitivity to 8 primary typing phages: the JF group (JF1, JF2, JF3, and JF4), phage D302, and the AN group (AN3, AN9, and AN1-8). The 3 auxiliary phages (VC3, VA6, and D32) define subgroups of the strains sensitive to the AN phages. A total of 99 strains were sensitive to at least 1 phage. Of 31 serotype 1 or 2 strains from animals, 13 were sensitive to AN phages but resistant to JF phages. In contrast, 7/33 serotype 4 or 8 strains from animals or from persons with AIDS were sensitive to JF phages but not to the AN phages. Of the clinical isolates not associated with AIDS, 78/235 were phage sensitive. These strains could be divided roughly into 4 groups: sensitive to AN phages, sensitive to JF phages, sensitive to phage D302, and sensitive to multiple phages. Only 1 of the environmental isolates was phage sensitive. The results indicate that phage typing can subdivide this heterogeneous group of organisms and is a useful tool for epidemiological studies.