Newly introduced genomic prophage islands are critical determinants of in vivo competitiveness in the Liverpool Epidemic Strain of Pseudomonas aeruginosa
Newly introduced genomic prophage islands are critical determinants of in vivo competitiveness in the Liverpool Epidemic Strain of Pseudomonas aeruginosa
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DOI：
10.1101/gr.086082.108
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发表时间：
2009-01-01
期刊：
影响因子：
7
通讯作者：
Levesque, Roger C.
中科院分区：
文献类型：
--
作者：
Winstanley, Craig;Langille, Morgan G. I.;Levesque, Roger C.
铜绿假单胞菌分离株具有高度保守的核心基因组，占总基因组序列的90%，具有额外的可变辅助基因，其中许多存在于基因组岛或胰岛中。1996年在儿童囊性纤维化（CF）单位中鉴定出利物浦流行株（LES），随后在英国的几个中心进行了观察，这对以前普遍认为CF患者仅从环境中获得独特的铜绿假单胞菌菌株的假设提出了挑战。为了了解形成这种重要流行毒株发展的力量，对最早存档的LES分离株LESB 58的基因组进行了测序。该序列揭示了许多大的基因组岛的存在，包括五个原噬菌体簇，一个缺陷（绿脓菌素）的原噬菌体簇，和五个非噬菌体岛。为了确定这些簇的作用，进行了无偏标记的诱变研究，然后在慢性大鼠肺部感染模型中进行选择。通过测序鉴定了47个突变体，包括已知参与假单胞菌感染的几个基因中的突变体。此外，从四个原噬菌体群和一个基因组岛的基因进行了鉴定，并在与亲本分离株的直接竞争研究中;四个被证明在慢性大鼠肺部感染模型中对竞争力有强烈影响。这强烈表明，增强的体内竞争力是维持和多样化选择这些基因组前噬菌体基因的主要驱动力。
Pseudomonas aeruginosa isolates have a highly conserved core genome representing up to 90% of the total genomic sequence with additional variable accessory genes, many of which are found in genomic islands or islets. The identification of the Liverpool Epidemic Strain (LES) in a children's cystic fibrosis (CF) unit in 1996 and its subsequent observation in several centers in the United Kingdom challenged the previous widespread assumption that CF patients acquire only unique strains of P. aeruginosa from the environment. To learn about the forces that shaped the development of this important epidemic strain, the genome of the earliest archived LES isolate, LESB58, was sequenced. The sequence revealed the presence of many large genomic islands, including five prophage clusters, one defective (pyocin) prophage cluster, and five non-phage islands. To determine the role of these clusters, an unbiased signature tagged mutagenesis study was performed, followed by selection in the chronic rat lung infection model. Forty-seven mutants were identified by sequencing, including mutants in several genes known to be involved in Pseudomonas infection. Furthermore, genes from four prophage clusters and one genomic island were identified and in direct competition studies with the parent isolate; four were demonstrated to strongly impact on competitiveness in the chronic rat lung infection model. This strongly indicates that enhanced in vivo competitiveness is a major driver for maintenance and diversifying selection of these genomic prophage genes.