Central Department of Biotechnology, Tribhuvan University, Kathmandu, Nepal.
J Nepal Health Res Counc. 2021 Apr 23;19(1):76-82. doi: 10.33314/jnhrc.v19i1.3282.
Global emergence of carbapenem-resistant Klebsiella pneumoniae is a major public health concern. Phage therapy - application of lytic phage to kill pathogenic bacteria - is considered as one of the promising alternatives to tackle this antibiotic crisis in recent days. This study aimed to isolate, characterize and evaluate therapeutic efficacy of a novel K. pneumoniae phage in mouse model.
A novel lytic bacteriophage (phage) Kp_Pokalde_002 was isolated against carbapenem-resistant K. pneumoniae (Kp56) and characterized. Safety parameters of the phage were evaluated by bioinformatic analysis of its genome. A lethal dose (1×107 CFU/mouse) of Kp56 was determined and administrated in the mice. The infected mice were treated with phage Kp_Pokalde_002 at a multiplicity of infection (MOI) 1.0 (1×107 PFU/mouse) via both oral and intraperitoneal (IP) routes.
Isolated phage comprised an icosahedral capsid with a short tail. Based on genome analysis, the phage was strictly lytic belonging the Podoviridae family (T7-like viruses) and free from any virulent and antibiotic-resistant genes. The phage was stable up to 60 °C for 30 minutes and effective between pH 4 to 11 (optimum pH 9). The phage exhibited a short latent period (20 minutes) with burst size of 121 phage particles per infected cell. The infected mice were rescued with the phage therapy via both oral and IP route. Significant reduction of bacterial load (3-7 log10 CFU/ml) in the blood and lung was observed in the treatment group.
We provide an evidence of successful phage therapy against carbapenem-resistant K. pneumoniae infected mouse model using locally isolated lytic phage.
全球范围内耐碳青霉烯类肺炎克雷伯菌的出现是一个主要的公共卫生关注点。噬菌体疗法——应用裂解噬菌体来杀死致病菌——被认为是应对抗生素危机的有前途的替代方法之一。本研究旨在分离、鉴定并评估新型肺炎克雷伯菌噬菌体在小鼠模型中的治疗效果。
分离并鉴定了一株针对耐碳青霉烯类肺炎克雷伯菌（Kp56）的新型裂解噬菌体（噬菌体）Kp_Pokalde_002。通过对其基因组进行生物信息学分析，评估了噬菌体的安全性参数。确定了致死剂量（1×107 CFU/只小鼠），并在小鼠中进行了实验。用噬菌体 Kp_Pokalde_002 以感染复数（MOI）1.0（1×107 PFU/只小鼠）通过口服和腹腔内（IP）途径对感染的小鼠进行治疗。
分离出的噬菌体由一个短尾的二十面体衣壳组成。根据基因组分析，该噬菌体是严格的裂解噬菌体，属于肌尾噬菌体科（T7 样病毒），不含任何毒力和抗生素耐药基因。噬菌体在 60°C 下稳定 30 分钟，在 pH4 到 11 之间有效（最佳 pH9）。噬菌体潜伏期短（20 分钟），每个感染细胞的爆发量为 121 个噬菌体颗粒。通过口服和 IP 途径进行噬菌体治疗后，感染的小鼠得到了挽救。在治疗组中，血液和肺部的细菌负荷（3-7log10 CFU/ml）显著减少。
我们提供了使用本地分离的裂解噬菌体成功治疗耐碳青霉烯类肺炎克雷伯菌感染小鼠模型的证据。
