Beta-lactams are commonly used antibiotics that prevent cell-wall biosynthesis. Beta-lactam sensitive bacteria can acquire conjugative resistance elements and hence become resistant even after being exposed to lethal (above minimum inhibitory) antibiotic concentrations. Here we show that neither the length of antibiotic exposure (1 to 16 h) nor the beta-lactam type (penam or cephem) have a major impact on the rescue of sensitive bacteria. We demonstrate that an evolutionary rescue can occur between different clinically relevant bacterial species (Klebsiella pneumoniae and Escherichia coli) by plasmids that are commonly associated with extended-spectrum beta-lactamase (ESBL) positive hospital isolates. As such, it is possible that this resistance dynamic may play a role in failing antibiotic therapies in those cases where resistant bacteria may readily migrate into the proximity of sensitive pathogens. Furthermore, we engineered a Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) -plasmid to encode a guiding CRISPR-RNA against the migrating ESBL-plasmid. By introducing this plasmid into the sensitive bacterium, the frequency of the evolutionarily rescued bacteria decreased by several orders of magnitude. As such, engineering pathogens during antibiotic treatment may provide ways to prevent ESBL-plasmid dispersal and hence resistance evolution.

中文翻译：

---

长期暴露于致死性抗生素浓度后，β-内酰胺敏感性细菌可通过缀合获得ESBL抗性。

β-内酰胺类是常用的防止细胞壁生物合成的抗生素。β-内酰胺敏感性细菌可以获得结合抗性元素，因此即使暴露于致死性（高于最低抑制性）抗生素浓度下也具有抗性。在这里，我们表明，抗生素暴露的时间（1至16小时）和β-内酰胺类型（penam或cephem）都不会对敏感细菌的挽救产生重大影响。我们证明，在不同的临床相关细菌种类（肺炎克雷伯菌和大肠杆菌）之间可能发生进化性拯救）质粒通常与广谱β-内酰胺酶（ESBL）阳性医院分离株有关。这样，在耐药细菌可能容易迁移到敏感病原体附近的那些情况下，这种耐药性动态可能会在抗生素治疗失败中起作用。此外，我们设计了一个聚簇的规则间隔的短回文重复序列（CRISPR）-质粒，以编码针对正在迁移的ESBL质粒的指导性CRISPR-RNA。通过将该质粒引入敏感细菌中，进化拯救的细菌的频率降低了几个数量级。这样，在抗生素治疗期间工程化的病原体可能提供防止ESBL质粒扩散并因此导致耐药性发展的方法。