Department of Clinical Sciences, Division of Infection Medicine, Lund University, Sweden.
BMC Genomics. 2011 Apr 19;12:198. doi: 10.1186/1471-2164-12-198.
Propionibacterium acnes is a Gram positive rod inhabiting the human skin that also infects orthopaedic implants and is associated with acne vulgaris. Previously, one lytic bacteriophage, PA6, from P. acnes has been sequenced and partially characterized. We recently isolated several inducible phages from P. acnes classified as Siphoviruses based on morphology and partial genome sequencing.
In this study we sequenced the inducible P. acnes phages PAD20 and PAS50, isolated from deep infection and from skin, respectively. The genomes of PAD20 and PAS50 are 29,074 and 29,017 bp, respectively, compared with the 29,739 bp of PA6. The phage genomes have 87.3-88.7% nucleotide sequence identity. The genes are divided into clusters with different levels of similarity between the phages. PAD20 and PAS50 share four genes encoding identical amino acid sequences. Some deletions and insertions in the genomes have occurred, resulting in lack of genes, frame shifts, and possible regulatory differences. No obvious virulence factor gene candidates were found. The phages are inducible, but bacteria can be cured of phages by serial colony isolations and lose their phages during stationary phase, but are still sensitive to new phage infections. Construction of a phylogenetic tree based on more than 459 phage genomes, suggested that P. acnes phages represent a new lineage of Siphoviruses.
The investigated P. acnes Siphovirus genomes share a high degree of homology to other P. acnes phages sequenced, but not to genomes of other phages isolated from Propionibacteria. The phage genomes are not integrated in the bacterial genome, but instead, most likely have a pseudolysogenic life cycle.
痤疮丙酸杆菌是一种革兰氏阳性杆菌，栖息在人类皮肤中，也会感染骨科植入物，并与寻常痤疮有关。以前，已经对痤疮丙酸杆菌的一种裂解噬菌体 PA6 进行了测序和部分特征描述。我们最近从痤疮丙酸杆菌中分离到几种诱导噬菌体，根据形态和部分基因组测序将其归类为长尾噬菌体科。
在这项研究中，我们对从深部感染和皮肤中分离到的诱导性痤疮丙酸杆菌噬菌体 PAD20 和 PAS50 进行了测序。PAD20 和 PAS50 的基因组分别为 29074bp 和 29017bp，而 PA6 的基因组为 29739bp。噬菌体基因组的核苷酸序列同一性为 87.3-88.7%。这些基因被分为不同簇，噬菌体之间具有不同程度的相似性。PAD20 和 PAS50 共享四个编码相同氨基酸序列的基因。基因组中发生了一些缺失和插入，导致基因缺失、框架移位和可能的调控差异。未发现明显的毒力因子候选基因。噬菌体是可诱导的，但细菌可以通过连续的菌落分离来清除噬菌体，并在静止期失去噬菌体，但仍对新噬菌体感染敏感。基于超过 459 个噬菌体基因组构建的系统发育树表明，痤疮丙酸杆菌噬菌体代表长尾噬菌体科的一个新谱系。
所研究的痤疮丙酸杆菌长尾噬菌体基因组与其他已测序的痤疮丙酸杆菌噬菌体具有高度同源性，但与从丙酸杆菌属分离到的其他噬菌体基因组没有同源性。噬菌体基因组未整合到细菌基因组中，而是很可能具有假溶原性生命周期。
