Table 7.

Effects of rdxA and frxAinactivation on H. pyloriphenotypea

StrainR and S values (in μg/ml) for:
Wild type rdxA::catfrxA::aphrdxA::cat frxA::aph
Type II strainb
 A2190.5R 1S 1R 1.5S 0.5R 1S 32R 64S
 SS1 0.5R 1S 1R 1.5S 1R 1.5S 32R 64S
 R100.5R 1S 1R 1.5S 1R 1.5S 32R 64S
A10103 0.5R 1S 1.5R 3S 0.5R 1S 32R 64S
 X47 1R 1.5S 1.5R 3S 1.5R 3S 32R 64S
 2600 (D. K.)c 1R 1.5S 1.5R 3S 1.5R 3S 32R 64S
 A381 0.5R 1S 3R 5S 0.5R 1S 32R 64S
 2667 (D. K.) 1R 1.5S 3R 5S 1.5R 3S 32R 64S
 2714 (D. K.) 1R 1.5S 5R 8S 1R 1.5S 32R 64S
 A10991R 1.5S 5R 8S 1R 1.5S 32R 64S
Type I control strain
 26695 1.5R 3S 16R 32S1.5R 3S 32R 64S
  • a R (as in 1R, 1.5R, etc.) refers to maximum concentration of MTZ that the H. pylori strain can tolerate; S (as in 1.5S, 3S, etc.) refers to minimum concentration of MTZ that will kill at least 99% of the culture and would correspond to the MIC value that is reported in traditional susceptibility testing of antimicrobial agents that are not mutagenic.

  • b The type II strains are grouped according to the change in resistance level that resulted from rdxAinactivation. This, we infer, is related inversely to the level offrxA expression.

  • c Strains studied by D. H. Kwon and associates (21) are identified with (D. K.).