Within host evolution - what does it say about the initial infecting population?

摘要

Background: There is evidence that colonising Gram-positive bacteria, including Staphylococcus aureus and Enterococcus faecium undergo in host micro-adaptive changes that result in genomic variation. This population evolution is relatively slow with accumulation of approximately 1 to 2 mutations per megabase per year. Little is known, however, about within host evolution in Gram-positive infections, especially bacteraemia as compared to colonisation. This is mainly due to the paucity of isolates and the emphasis on examining paired isolates in the context of antibiotic resistance development.