Phenotypic and Genomic Profiling of Staphylococcus argenteus in Canada and the United States and Recommendations for Clinical Result Reporting.

is a newly described species, formerly known as clonal complex 75 (CC75). Here, we describe the largest collection of isolates in North America, highlighting identification challenges. We present phenotypic and genomic characteristics and provide recommendations for clinical reporting. Between 2017 and 2019, 22 isolates of were received at 2 large reference laboratories for identification. Identification with routine methods (biochemical, matrix-assisted laser desorption ionization-time of flight mass spectrometry [MALDI-TOF MS], 16S rRNA gene analysis) proved challenging to confidently distinguish these isolates from Whole-genome sequencing analysis was employed to confirm identifications. Using several different sequence-based analyses, all clinical isolates under investigation were confirmed to be with clear differentiation from Seven of 22 isolates were recovered from sterile sites, 11 from nonsterile sites, and 4 from surveillance screens. While sequence types ST1223/ type XV, ST2198/ type XIV, and ST2793/ type XId were identified among the Canadian isolates, the majority of isolates (73%) belonged to multilocus sequence types (MLST) ST2250/ type XId and exhibited a high degree of homology at the genomic level. Despite this similarity, 5 types were identified among ST2250 isolates, demonstrating some diversity between strains. Several isolates carried , as well as other resistance and virulence determinants (e.g., PVL, TSST-1) commonly associated with Based on our findings, the growing body of literature on , the potential severity of infections, and possible confusion associated with reporting, including use of incorrect breakpoints for susceptibility results, we make recommendations for clinical laboratories regarding this organism.