Thoen, Charles O.

SUMMARY Lymph nodes with tuberculous lesions identified by federal meat inspectors were collected from 36 swine carcasses at an abattoir in southeastern Minnesota. Nonchromogenic mycobacteria were isolated by culture from 25. By animal pathogenicity and serologic tests, 24 of the 25 were identified as Mycobacterium avium and 1 was a Battey type. Corynebacterium equi was isolated from 4 lesions with M. avium and from 2 without other bacteria. Lesions with C. equi could not be distinguished from others either grossly or microscopically.

Fifty-eight strains of nonphotochromogenic mycobacteria representing nine different serotypes were studied, including 38 strains of Mycobacterium avium and 20 strains of Battey bacilli. The lipids were extracted from whole cells, saponified with potassium hydroxide, and esterified with diazomethane. The fatty-acid profiles determined by gas-liquid chromatography included saturated fatty acids ranging from C 8 to C 24 , plus some unsaturated analogues and a branched-chain acid. No consistent differences in the fatty-acid profiles were observed between strains of M. avium and Battey bacilli. Quantitative differences in the means (significant at P < 0.01) were observed in the relative amounts of 14:0, 16:1, 18:0, 18:1, and a branched-chain acid among strains of the same serotype. We were unable to differentiate the fatty-acid profiles of recently isolated strains or those maintained in culture for more than 2 years.

Specific agglutinins were produced in ascitic fluid of mice by intraperitoneal injection of certain mycobacteria suspended in Freund's incomplete adjuvant.

Comparison of the cellular fatty acids of 10 strains of Mycobacterium marinum and 35 strains of Mycobacterium kansasii revealed similarities within each species but differences between these two photochromogenic mycobacteria. A branched-chain fatty acid characteristic of M. kansasii was found in trace amounts in 2 of the 10 strains of M. marinum .

The cellular fatty acids of 35 strains of Mycobacterium kansasii isolated from clinical material were analyzed to establish properties by which we could identify and characterize these acid-fast microorganisms. The fatty acids were extracted from cells grown in liquid synthetic media, and they were analyzed as methyl esters by gas-liquid chromatography. The fatty acid profiles of all strains were similar. They differed from fatty acid profiles of other mycobacteria by their content of a saturated fatty acid with a methyl group at C2.