As these isolates were negative for sak, chps, and scin, genes that are encoded on a bacteriophage [17], it is highly likely that they lost this phage in the course of bacterial adaptation to the animal host, in which genes which provide protection against the human host defense, are not required and are dispensable [10], while a loss during chronic airway infection of the respective CF patient is less likely in these LA-MRSA isolates [31]. This evidence concerns the gene PLK4 and cystic fibrosis.