. 2002 May;46(5):1204–1211. doi: 10.1128/AAC.46.5.1204-1211.2002

TABLE 5.

Fixation and elimination of drug resistance mutations carrying different costs of resistance

Cost of resistance (%)	No. of generations for:
Cost of resistance (%)	Fixation by compensatory mutation^a	Elimination^b
2	912	1,139
5	359	449
10	175	218
20	83	103

Assuming a frequency of 10⁻⁶ of a compensatory mutation restoring fitness; the values are the number of generations (t) required for the compensated resistance genotype to become fixed, i.e., to represent 99% of the drug-resistant population, determined by the following formula: t = ln[(rc_t/r_t)/(rc_t−1/r_t−1)]/ln(1 − cost per generation), where rc_t and rc_t−1 are absolute numbers of resistant mutants with a compensatory mutation.

Calculated for a ratio of resistant to susceptible organisms of 99:1 at time zero; the values are the number of generations (t) to reach levels of spontaneous drug resistance frequency (10⁻⁸) determined by the following formula: t = ln[10⁻⁸ (r₀/S₀)]/ln(1 − cost per generation).