Data from: Sublethal streptomycin concentrations and lytic bacteriophage together promote resistance evolution

Sub-minimum inhibiting concentrations (sub-MICs) of antibiotics frequently occur in natural environments owing to wide-spread antibiotic leakage by human action. Even though the concentrations are very low, these sub-MICs have recently been shown to alter bacterial populations by selecting for antibiotic resistance and increasing the rate of adaptive evolution. However, studies are lacking on how these effects reverberate into key ecological interactions, such as bacteria–phage interactions. Previously, co-selection of bacteria by phages and antibiotic concentrations exceeding MICs has been hypothesized to decrease the rate of resistance evolution because of fitness costs associated with resistance mutations. By contrast, here we show that sub-MICs of the antibiotic streptomycin (Sm) increased the rate of phage resistance evolution, as well as causing extinction of the phage. Notably, Sm and the phage in combination also enhanced the evolution of Sm resistance compared with Sm alone. These observations demonstrate the potential of sub-MICs of antibiotics to impact key ecological interactions in microbial communities with evolutionary outcomes that can radically differ from those associated with high concentrations. Our findings also contribute to the understanding of ecological and evolutionary factors essential for the management of the antibiotic resistance problem.抗生素的亚最低抑菌浓度（sub-MICs）常因人类活动导致的抗生素广泛泄漏而广泛存在于自然环境中。尽管这类浓度极低，但近期研究表明，亚最低抑菌浓度可通过筛选抗生素耐药性菌株、提升适应性进化速率来改变细菌种群结构。然而，目前尚缺乏针对此类效应如何波及细菌-噬菌体（phage）这类关键生态相互作用的相关研究。此前有假说提出，当噬菌体与超过最低抑菌浓度（MICs）的抗生素共同对细菌施加共选择压力时，由于耐药突变会带来适合度代价，耐药性进化速率会降低。与之相反，本研究显示，抗生素链霉素（streptomycin, Sm）的亚最低抑菌浓度不仅提升了噬菌体抗性的进化速率，还导致了噬菌体的灭绝。值得注意的是，与单独使用链霉素相比，链霉素与噬菌体联合处理还进一步促进了链霉素耐药性的进化。上述研究结果表明，抗生素亚最低抑菌浓度能够影响微生物群落中的关键生态相互作用，其引发的进化结局与高浓度抗生素所带来的结果截然不同。本研究结果还有助于深化对抗生素耐药性防控所需的关键生态与进化因素的理解。