BIOCHEMICAL CHARACTERISTICS OF VARIOUS STRAINS OF MYCOBACTERIUM-PARATUBERCULOSIS

  • 1 July 1986
    • journal article
    • research article
    • Vol. 47  (7) , 1442-1445
Abstract
Biochemical activities of 20 wild-type strains and of 2 laboratory strains of Mycobacterium paratuberculosis were evaluated. Biochemical activities evaluated were growth at 30.degree. C, 37.degree. C, and 42.degree. C; production of urease, niacin, pyrazinamidase, arylsulfatase, and catalase; hydrolyzation of Tween 80; reduction of nitrate and tellurite; and growth in 5% NaCl. Antimicrobial susceptibility to thiophene-2-carboxylic acid hydrazide (10 .mu.g/ml), neotetrazolium chloride (1:40,000), streptomycin (2 .mu.g/ml), rifampin (0.25 .mu.g/ml), and isoniazid (10 .mu.g/ml) also was determined. Generally, M. paratuberculosis was biochemically inactive, with only a few strains producing pyrazinamidase and maintaining catalase activity after heating. All strains grew optimally at 37.degree. C, grew slightly at 30.degree. C, and did not grow at 42.degree. C. Wild-type strains did not grow in the presence of neotetrazolium chloride, streptomycin, and rifampin, and grew in the presence of thiophene-2-carboxylic acid hydrazine and isoniazid. Although biochemical evaluation can be used as an aid in the identification of M. paratuberculosis, growth rate, and mycobactin dependency remain major criteria for positive identification.