Bovine tuberculosis in the United States and Puerto Rico: a laboratory summary.

Mycobacteria were isolated from 14.3% of the tissues submitted to the National Veterinary Services Laboratories over a 5-year period (July 1, 1972, to June 30, 1977). The isolates were identified by drug susceptibility, and biochemical and serologic tests. Mycobacterium bovis isolated from tissues of cattle originating in 32 states and Puerto Rico accounted for 78% of the acid-fast isolations. Of the Mycobacterium bovis isolates, 4% were from tissues in which no microscopic tuberculous granulomas were observed on examination of tissue sections. Of the 119 Mycobacterium avium isolates, 18 were serotype 1, 44 were serotype 2, and 45 isolates represented 12 other serotypes.