TABLE 4.

Frequency of rifampin resistance in E. coli tester strain CC104

Strain, compound, and concn (μg/ml)aSurvivalbRifr frequency (per 108)cFold
CC104
    Nitazoxanide
        014.8
        516.7
        1012.6
CC104(pGS950)
    Nitazoxanide
        017.0
        515.5
        1016.3
CC104
    Nitrofurazone
        013.36
        1126.47.9
        20.758.617.4
        510−375.422.4
    Nitrofurantoin
        013.36
        10.96.141.8
        20.98.592.6
        52.5 × 10−232.589.7
    Furazolidone
        013.36
        0.110−264.019
        110−30
Controld
    Metronidazole
        010.75
        510−25370
        1010−4378504
  • a The bacteria (E. coli CC104 + pBSK or CC104 + pGS950rdxA+) were grown on LB agar with the appropriate concentration of drug and then plated on medium containing rifampin as indicated in the text.

  • b EOP − efficiency of plating (EOP of 1 = no loss of viability).

  • c The Rifr frequencies represent the means of three determinations and are reported as the number of Rifr colonies per 108 bacteria plated.

  • d Similar to data of Sisson et al. (29); included for comparison. Control, CC104(pGS950).