FIG 1 .

Growth competition between the parental strain and RND pump-overexpressing strains. (A) For adeABC overexpression, parental A. baumannii BM4587 strain and BM4688[↗adeABC] or BM4689[↗adeABC] were used. (B) For adeFGH overexpression, strains BM4587 and BM4690[↗adeFGH] or BM4691[↗adeFGH] were used. (C) For adeIJK overexpression, strains BM4587 and BM4666[↗adeIJK] were used. (A to C) For all experiments shown, the strains were mixed at a 1:1 ratio at an initial inoculum of 5 × 10⁴ CFU and transferred every 12 h (corresponding to approximately 20 generations) in fresh medium for up to six passages. The competition index (CI) was calculated as the CFU ratio of the resistant and susceptible strains (R/S) at time t₁ divided by the same R/S at time t₀, and the selection coefficient s was then calculated as the slope of the following linear regression model s = ln (CI)/[t × ln (2)], where t is the number of generations. Every experiment was carried out in du plicate in four independent experiments, and the results are presented as means ± SD (error bars).