Genotypic and Phenotypic Diversity of Staphylococcus aureus Isolates from Cystic Fibrosis Patient Lung Infections and Their Interactions with Pseudomonas aeruginosa.

has recently overtaken as the most commonly recognized bacterial pathogen that infects the respiratory tracts of individuals with the genetic disease cystic fibrosis (CF) in the United States. Most studies of in CF patient lung infections have focused on a few isolates, often exclusively laboratory-adapted strains, and how they are killed by Less is known about the diversity of CF patient lung isolates in terms of both their virulence and their interaction with To begin to address this gap, we recently sequenced 64 clinical isolates and a reference isolate, JE2. Here, we analyzed the antibiotic resistance genotypes, sequence types, clonal complexes, types, types, and presence/absence of other known virulence factor genes of these isolates. We hypothesized that virulence phenotypes of , namely, toxin production and the mucoid phenotype, would be lost in these isolates due to adaptation in the CF patient lung. In contrast to these expectations, we found that most isolates can lyse both rabbit and sheep blood (67.7%) and produce polysaccharide (69.2%), suggesting that these phenotypes were not lost during adaptation to the CF lung. We also identified three distinct phenotypic groups of based on their survival in the presence of nonmucoid laboratory strain PAO1 and its mucoid derivative. Altogether, our work provides greater insight into the diversity of isolates from CF patients, specifically the distribution of important virulence factors and their interaction with , all of which have implications in patient health. is now the most frequently detected recognized pathogen in the lungs of individuals who have cystic fibrosis (CF) in the United States, followed closely by When these pathogens are found to coinfect the CF lung, patients have a significantly worse prognosis. While has been rigorously studied in the context of bacterial pathogenesis in CF, less is known about Here, we present an in-depth study of 64 clinical isolates from CF patients, for which we investigated genetic diversity utilizing whole-genome sequencing, virulence phenotypes, and interactions with We found that isolated from CF lungs are phylogenetically diverse; most retain known virulence factors and vary in their interactions with (i.e., they range from being highly sensitive to to completely tolerant to it). Deepening our understanding of how responds to its environment and other microbes in the CF lung will enable future development of effective treatments and preventative measures against these formidable infections.