Table 1.

Biochemical and genetical characteristics of M. tuberculosis H37Rv and the strains analyzeda

Organism and groupPZA sensitivityNiacin accumulationNitrate reductionGrowth in presence of TCHChange of color of bromcresol mediumColony morphology (growth)Growth on Lebek mediumPresence of mtb40Presence of pncA mutation (C to G)Presence of oxyR mutation (G to A)
M. tuberculosis H37Rv (n = 1)S++++EugonicAerophilic+
M. bovis
 Group 1 (n = 35)R (100)b− (100)− (100)− (100)− (100)Dysgonic (100)Microaerophilic (100)− (100)c+ (100)d+ (100)d
 Group 2 (n = 15)S (100)− (100)− (100)− (94), + (6)e− (100)Dysognic (100)Microaerophilic (100)− (100)− (100)d+ (100)d
 Group 3 (n = 2)S (100)− (100)− (100)− (100)− (100)Dysognic (100)Microaerophilic (100)− (100)− (100)+ (100)
M. africanum
 Group 4 (n = 20)S (100)+ (55), − (45)+ (65), − (35)− (85), + (15)e− (100)Dysognic (100)Microaerophilic (100)+ (70), − (30)− (100)d− (100)d
 Group 5 (n = 24)S (100)+ (30), − (70)+ (100)+ (100)− (100)Dysognic (100)Microaerophilic (100)+ (100)− (100)d− (100)d
  • a Abbreviations and symbols: S, susceptible, R, resistant; +, positive test result; −, negative test result.

  • b Values in parentheses are percentage of isolates.

  • c Ten randomly chosen strains were tested.

  • d Five randomly chosen strains were tested.

  • e Strains were resistant to isoniazid and cross-resistant to TCH.