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Phylogeographic variation in recombination rates within a global clone of methicillin-resistant Staphylococcus aureus

2012; BioMed Central; Volume: 13; Issue: 12 Linguagem: Inglês

10.1186/gb-2012-13-12-r126

1474-760X

Santiago Castillo‐Ramírez, Jukka Corander, Pekka Marttinen, Mona Aldeljawi, William P. Hanage, Henrik Westh, Kit Boye, Zeynep Gülay, Stephen D. Bentley, Julian Parkhill, Matthew T. G. Holden, Edward J. Feil,

Escherichia coli research studies

Abstract Background Next-generation sequencing (NGS) is a powerful tool for understanding both patterns of descent over time and space (phylogeography) and the molecular processes underpinning genome divergence in pathogenic bacteria. Here, we describe a synthesis between these perspectives by employing a recently developed Bayesian approach, BRATNextGen, for detecting recombination on an expanded NGS dataset of the globally disseminated methicillin-resistant Staphylococcus aureus (MRSA) clone ST239. Results The data confirm strong geographical clustering at continental, national and city scales and demonstrate that the rate of recombination varies significantly between phylogeographic sub-groups representing independent introductions from Europe. These differences are most striking when mobile non-core genes are included, but remain apparent even when only considering the stable core genome. The monophyletic ST239 sub-group corresponding to isolates from South America shows heightened recombination, the sub-group predominantly from Asia shows an intermediate level, and a very low level of recombination is noted in a third sub-group representing a large collection from Turkey. Conclusions We show that the rapid global dissemination of a single pathogenic bacterial clone results in local variation in measured recombination rates. Possible explanatory variables include the size and time since emergence of each defined sub-population (as determined by the sampling frame), variation in transmission dynamics due to host movement, and changes in the bacterial genome affecting the propensity for recombination.