Table 2 Frequency of spontaneous rifampicin resistance before and after antibiotic exposure.

From: Access to high-impact mutations constrains the evolution of antibiotic resistance in soft agar

Lineage f (×108)b μ (×108)
MG1655 4.0 ± 2.1 1.1
MG1655 Post speed selectiona 64.6 ± 9.8 12.8
E. coli BW25113 ΔmutL 188 ± 4.3 31.1
E. coli BW25113 ΔmutL
Post speed selectiona
19.2 ± 12.8 4.3
E. coli BW25113 ΔmutS 650 ± 134.5 82.9
E. coli BW25113 ΔmutS
Post speed  selectiona
45.3 ± 4.0 7.8
Ampicillin 1-1 57.3 ± 27.7 18.3
Polymyxin B 1 312 ± 90 66.8
Polymyxin B 1-1 17.1 ± 6.2 6.4
Polymyxin B 1-2 15.6 ± 2.7 5.8
Polymyxin B 2 71.6 ± 13.4 19.9
  1. aAfter selection for efficient swimmers, prior to antibiotic exposure. bAverage of three technical replicates.