一株耐碳青霉烯类鲍曼不动杆菌噬菌体的分离鉴定和临床应用

Isolation, identification, and clinical application of a novel phage targeting carbapenem-resistant Acinetobacter baumannii

摘要:

【背景】耐药菌感染是人类生命健康的重要威胁，寻找抗生素替代或辅助疗法迫在眉睫，噬菌体是细菌的天敌，有很大的开发潜力。【目的】分离针对耐碳青霉烯类鲍曼不动杆菌(carbapenem-resistantAcinetobacter baumannii, CRAB)的烈性噬菌体，治疗患者CRAB肺部感染，为噬菌体疗法的推广积累经验。【方法】用CRAB临床菌株NAB11B做宿主菌，从医院污水中分离新噬菌体，进行生物学特征和基因组特点的表征、分析后制备成高纯度的噬菌体制剂，通过雾化吸入的方式治疗肺部CRAB感染，评估噬菌体疗法的有效性和安全性。【结果】分离到一株新噬菌体，命名为AB_SZL4，其潜伏期短、增殖速度快、抑菌能力强、生物学稳定性高且不携带有害基因。在临床应用中，噬菌体鸡尾酒联合抗生素疗法能快速清除肺部病原菌，且未见明显噬菌体相关不良反应。【结论】AB_SZL4是一株有极大临床应用潜力的烈性噬菌体。

Abstract:

[Background] Infections by antibiotic-resistant pathogens pose tremendous threats to human health, and there is an urgent need to develop alternative or adjuvant therapies for classic antibiotics. Phages as the natural predators of bacteria demonstrate promising prospects in treating bacterial infections. [Objective] To isolate virulent phages against carbapenem-resistant Acinetobacter baumannii (CRAB) and then treat CRAB-caused pulmonary infection with the isolated phages.[Methods] We isolated new phages from hospital sewage by using the CRAB clinical strain NAB11B as the host bacteria and then studied the biological and genomic characteristics of the isolated phages. Subsequently, we employed aerosol inhalation of a phage cocktail to treat a patient with CRAB pulmonary infection. Finally, we evaluated the efficacy and safety of phage therapy. [Results] We isolated a novel phage AB_SZL4, which could produce a transparent plaque with a halo in NAB11B lawn and inhibit the growth of NAB11B at low multiplicity of infection (MOI). AB_SZL4 showed the latent period of about 15 min and the burst size of 75 PFU/cell. AB_SZL4 remained stable at pH 3.0–11.0 and 70℃ and below. There was no detrimental gene in the genome of AB_SZL4. NAB11B was eliminated following phage therapy combined with antibiotics within a week, and no phage-related side effect was observed. [Conclusion] AB_SZL4 is a potent lytic phage with great potential for clinical application.