TABLE 2.

Sensitivity of two M. tuberculosis strains and one M. avium strain to peroxidase activities^a

Exptl condition	% Growth of:
	M. tuberculosis H37Rv	M. tuberculosis H19b	M. avium 485
Control	100	100 A	100
MPO + H2O2	15	29 ± 14 B	45
MPO	92	80 ± 34 C	100
HRP + H2O2c	89	NDd	ND
H2O2	100	80 ± 15 D	52

^aValues are expressed as percentages (± standard deviations) of growth, taking the number of CFU of untreated bacteria as 100%. The concentration of MPO was 3 GU/10⁶ M. tuberculosis and M. avium cells, and the concentration of HRP was 18 GU/10⁶ M. tuberculosis cells. Two experiments each were conducted for M. tuberculosis H37Rv and M. avium 485; three experiments were conducted for M. tuberculosis H19. See Materials and Methods for more details. 

^bB versus A, P < 0.015 (significant); C versus A and A versus D, not significant; B versus C, P < 0.002 (very significant). All results by two-tailed Student’s t test. 

^cThese experiments were carried out in 0.02 M sodium phosphate buffer (pH 7.0) containing 0.067 M sodium sulfate and 0.2 mM NaI. 

^dND, not done.