Investigation

Now that you have obtained and annotated a phylogenetic tree from the study isolates, you can begin to consider some questions that might lead you to understand paths of transmission in 15  Tracing the Source.

You have information about the sample location for each isolate, whether it was sampled from a patient or the hospital environment, and a presumed order of divergence of the isolates that were sequenced. This should be enough to form a working hypothesis for how the P. aeruginosa isolates spread and were acquired by the patients.