Department of Biological Sciences, 6-008 Centennial Centre for Interdisciplinary Science, University of Alberta, Edmonton, AB T6G 2E9 Canada.
BMC Genomics. 2013 Aug 27;14:574. doi: 10.1186/1471-2164-14-574.
As is true for many other antibiotic-resistant Gram-negative pathogens, members of the Burkholderia cepacia complex (BCC) are currently being assessed for their susceptibility to phage therapy as an antimicrobial treatment. The objective of this study was to perform genomic and limited functional characterization of the novel BCC phage JG068 (vB_BceP_JG068).
JG068 is a podovirus that forms large, clear plaques on Burkholderia cenocepacia K56-2. Host range analysis indicates that this phage can infect environmental, clinical, and epidemic isolates of Burkholderia multivorans, B. cenocepacia, Burkholderia stabilis, and Burkholderia dolosa, likely through interaction with the host lipopolysaccharide as a receptor. The JG068 chromosome is 41,604 base pairs (bp) in length and is flanked by 216 bp short direct terminal repeats. Gene expression originates from both host and phage promoters and is in the forward direction for all 49 open reading frames. The genome sequence shows similarity to Ralstonia phage ϕRSB1, Caulobacter phage Cd1, and uncharacterized genetic loci of blood disease bacterium R229 and Burkholderia pseudomallei 1710b. CoreGenesUniqueGenes analysis indicates that JG068 belongs to the Autographivirinae subfamily and ϕKMV-like phages genus. Modules within the genome encode proteins involved in DNA-binding, morphogenesis, and lysis, but none associated with pathogenicity or lysogeny. Similar to the signal-arrest-release (SAR) endolysin of ϕKMV, inducible expression of the JG068 SAR endolysin causes lysis of Escherichia coli that is dependent on the presence of an N-terminal signal sequence. In an in vivo assay using the Galleria mellonella infection model, treatment of B. cenocepacia K56-2-infected larvae with JG068 results in a significant increase in larval survival.
As JG068 has a broad host range, does not encode virulence factors, is obligately lytic, and has activity against an epidemic B. cenocepacia strain in vivo, this phage is a highly promising candidate for BCC phage therapy development.
与许多其他抗生素耐药性革兰氏阴性病原体一样，伯克霍尔德氏菌复合群（BCC）的成员目前正在作为一种抗菌治疗方法进行噬菌体治疗的敏感性评估。本研究的目的是对新型 BCC 噬菌体 JG068（vB_BceP_JG068）进行基因组和有限功能表征。
JG068 是一种 Podovirus，可在伯克霍尔德氏菌 cenocepacia K56-2 上形成大而清晰的噬菌斑。宿主范围分析表明，该噬菌体可以感染环境、临床和流行的伯克霍尔德氏菌多沃拉森、B. cenocepacia、伯克霍尔德氏菌稳定和伯克霍尔德氏菌多洛萨，可能通过与宿主脂多糖作为受体相互作用。JG068 染色体长 41604 个碱基对（bp），两端为 216 bp 短直接末端重复序列。基因表达源自宿主和噬菌体启动子，所有 49 个开放阅读框均为正向。基因组序列与 Ralstonia 噬菌体ϕRSB1、Caulobacter 噬菌体 Cd1 以及血液疾病细菌 R229 和 Burkholderia pseudomallei 1710b 的未鉴定遗传基因座具有相似性。CoreGenesUniqueGenes 分析表明，JG068 属于 Autographivirinae 亚科和ϕKMV-like 噬菌体属。基因组内的模块编码参与 DNA 结合、形态发生和裂解的蛋白质，但没有与致病性或溶原性相关的蛋白质。与ϕKMV 的信号-停止-释放（SAR）内溶素相似，诱导表达 JG068 SAR 内溶素会导致依赖于 N 端信号序列存在的大肠杆菌裂解。在使用 Galleria mellonella 感染模型的体内试验中，用 JG068 处理感染 B. cenocepacia K56-2 的幼虫可显著提高幼虫的存活率。
由于 JG068 具有广泛的宿主范围、不编码毒力因子、是必需裂解的，并且在体内对流行的 B. cenocepacia 菌株具有活性，因此该噬菌体是开发 BCC 噬菌体治疗的极具前景的候选物。
