Crippen Clay S, Jr Michael J Rothrock, Sanchez Susan, Szymanski Christine M
Department of Microbiology and Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States.
United States National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, GA, United States.
Front Microbiol. 2020 Aug 14;11:1918. doi: 10.3389/fmicb.2020.01918. eCollection 2020.
Antimicrobial resistance is an ancient bacterial defense mechanism that has rapidly spread due to the frequent use of antibiotics for disease treatment and livestock growth promotion. We are becoming increasingly aware that pathogens, such as members of the genus , are precipitously evolving drug resistances through multiple mechanisms, including the acquisition of antibiotic resistance genes. In this study, we isolated three multidrug resistant species from birds on a free-range farm. , , and were isolated from hens, turkeys and ducks and were resistant to 14 clinically relevant antibiotics, including several listed by the World Health Organization as essential medicines. Co-culturing any of the three species with resulted in contact-dependent release of intact resistance determinants. We also isolated several lytic bacteriophages and selected two of these phages to be included in this study based on differences in plaquing characteristics, nucleic acid content and viral morphology. Both phages released host DNA, including antibiotic resistance genes during cell lysis and we demonstrated that these resistance determinants were transferable to a naïve strain of . This study demonstrates that contact-dependent competition between bacterial species can readily contribute to DNA release into the environment, including antibiotic resistance determinants. We also highlight that the constant lysis and turnover of bacterial populations during the natural lifecycle of a lytic bacteriophage is an underappreciated mechanism for the liberation of DNA and subsequent genetic exchange.
抗菌耐药性是一种古老的细菌防御机制，由于抗生素频繁用于疾病治疗和促进家畜生长，它已迅速传播。我们越来越意识到，诸如 属成员之类的病原体正在通过多种机制急剧进化出耐药性，包括获得抗生素耐药基因。在本研究中，我们从一个自由放养农场的鸟类中分离出三种多重耐药的 物种。 、 和 分别从母鸡、火鸡和鸭子中分离出来，它们对14种临床相关抗生素具有耐药性，其中包括世界卫生组织列为基本药物的几种抗生素。将这三种 物种中的任何一种与 共同培养都会导致完整耐药决定簇的接触依赖性释放。我们还分离出了几种裂解性噬菌体，并根据噬菌斑特征、核酸含量和病毒形态的差异选择了其中两种噬菌体纳入本研究。两种噬菌体在细胞裂解过程中都会释放宿主DNA，包括抗生素耐药基因，并且我们证明这些耐药决定簇可以转移到 的一个未接触过的菌株中。这项研究表明，细菌物种之间的接触依赖性竞争很容易导致DNA释放到环境中，包括抗生素耐药决定簇。我们还强调，在裂解性噬菌体的自然生命周期中，细菌群体的持续裂解和更新是一种未被充分认识的DNA释放和随后基因交换的机制。
