Extensive phage dynamics in Staphylococcus aureus contributes to adaptation to the human host during infection
Extensive phage dynamics in Staphylococcus aureus contributes to adaptation to the human host during infection
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DOI：
10.1111/j.1365-2958.2006.05354.x
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发表时间：
2006-09-01
影响因子：
3.6
通讯作者：
Wolz, Christiane
中科院分区：
文献类型：
--
作者：
Goerke, Christiane;Wirtz, Christiane;Wolz, Christiane
噬菌体是微生物进化、适应新环境和人类细菌感染发病机制的驱动力。在金黄色葡萄球菌中，编码免疫逃避分子(SAK、SCIN、CHIP)的噬菌体广泛分布，它与β-溶血素(HLB)基因特异整合。当比较感染和定植情况下的金黄色葡萄球菌菌株时，我们可以检测到SAK编码的噬菌体易位到细菌中非典型的基因组整合位点，只有在与疾病相关的分离株中。此外，在感染性菌株收集中检测到明显更多的HLB产生菌株。通过对患者的共生和连续分离株的分析，显示了感染期间广泛的噬菌体动态(基因组内移位、复制、宿主间转移、重组事件)。这种活性导致菌株群体分裂成不同的亚组分，显示出不同的毒力潜力(产生HLB和/或产生免疫逃避分子)。因此，噬菌体的诱导条件和细菌宿主在噬菌体运动后的强烈选择是典型的感染情况。对噬菌体的进一步体外鉴定表明：(I)SAK不仅编码在F群噬菌体上，而且编码在总是整合在不同基因间隔区的B群噬菌体上；(Ii)SAK转录水平与噬菌体诱导能力有关，但与噬菌体在染色体上的定位无关；(Iii)噬菌体在其生命周期中可以在染色体外稳定。
Bacteriophages serve as a driving force in microbial evolution, adaptation to new environments and the pathogenesis of human bacterial infections. In Staphylococcus aureus phages encoding immune evasion molecules (SAK, SCIN, CHIPS), which integrate specifically into the beta-haemolysin (Hlb) gene, are widely distributed. When comparing S. aureus strain collections from infectious and colonizing situations we could detect a translocation of sak-encoding phages to atypical genomic integration sites in the bacterium only in the disease-related isolates. Additionally, significantly more Hlb producing strains were detected in the infectious strain collection. Extensive phage dynamics (intragenomic translocation, duplication, transfer between hosts, recombination events) during infection was shown by analysing cocolonizing and consecutive isolates of patients. This activity leads to the splitting of the strain population into various subfractions exhibiting different virulence potentials (Hlb-production and/or production of immune evasion molecules). Thus, phage-inducing conditions and strong selection for survival of the bacterial host after phage movement are typical for the infectious situation. Further in vitro characterization of phages revealed that: (i) SAK is encoded not only on serogroup F phages showing a conserved tropism for hlb but also on serogroup B phages which always integrate in a distinct intergenic region, (ii) the level of sak transcription correlates to phage inducibility but is independent of the phage localization in the chromosome, and (iii) phages can be stabilized extra-chromosomally during their life cycle.