Insights from Genomics into Bacterial Pathogen Populations
Lieberman, Michel, and colleagues  sequenced the genomes of 112 isolates of Burkholderia dolosa from 14 cystic fibrosis patients involved in an outbreak in Boston, Massachusetts in the 1990s. (A) The maximum likelihood tree relating the bacterial genomes, color-coded by patient, is broadly consistent with a single founding infection for each patient. (B) The date of sampling and the chronological accumulation of mutations implied a network of transmission events. (C) Interesting patterns emerged when comparing bacteria isolated from different sites in the same patient. For two patients (subjects K and N), multiple genotypes appeared to have been transmitted from the airways to the bloodstream during septicemia, either concurrently or over the course of the infection. By contrast, a single genotype appeared to have been transmitted from the airways to the bloodstream in subject H. Reproduced from  appearing in Nature Genetics (Volume 43, 2011).