TABLE 2.

Mutation frequency to rifampin resistance after UV irradiation and chronic exposure to the quinolone nalidixic acida

TreatmentAvg ± SD
% SurvivalFrequency (10−8)Fold increase for L. pneumophila and E. colib
UV (J/m2)
    01004.1 ± 1.01
    596 ± 2110.8 ± 3.92.6 ± 1.1 (92)
    7.577 ± 2214.9 ± 6.93.6 ± 1.8 (178)
    1023 ± 1330.1 ± 6.47.3 ± 2.9 (223)
Nalidixic acid (μg/ml)
    01005.8 ± 1.01
    0.1627 ± 1110.8 ± 3.11.9 ± 0.8 (ND)
    0.240.8 ± 0.714.6 ± 7.92.6 ± 1.6 (ND)
  • a Values are averages from three independent experiments (n = 3). ND, not determined.

  • b The values for E. coli are given in parentheses.