Isolation of bacteriophage from Thermoactinomyces.

Bacteriophages were isolated from strains of Thermoactinomyces vulgaris, T. candidus, and T. sacchari used to produce antigen for hypersensitivity pneumonitis screening at the Marshfield Medical Foundation. Whereas the one phage isolated from T. sacchari and two phages from T. vulgaris were species specific, three other phages isolated from T. vulgaris and the two phages isolated from T. candidus were infectious for both T. vulgaris and T. candidus, thus indicating a close relationship between these two species. A simple reproducible scheme for classification of newly isolated T. vulgaris-T. candidus phages into seven groups on the basis of host range is presented. Examination of plaque morphology of the T. vulgaris-T. candidus phages supported the host range classification scheme. The ease of isolation of phages from cultures of Thermoactinomyces suggests that they are commonly associated with this genus.