Successful treatment of Staphylococcus argenteus sequence type 2198 uncomplicated bacteremia with a 2-week antibiotic course

There is a paucity of data on the clinical course and treatment of Staphylococcus argenteus. Herein, we describe a successfully treated case of S. argenteus bacteremia. A 76-year-old man with lung adenocarcinoma developed bacteremia caused by penicillin-resistant, oxacillin-susceptible S. argenteus, which was identified through mass spectrometry and nuc gene sequencing. He was diagnosed with a peripheral line-associated bloodstream infection and successfully treated with a 2-week course of cefepime, followed by cefazolin, concurrent with intravenous catheter removal. The isolate was positive for blaZ and negative for mecA. It was assigned to sequence type 2198 using multilocus sequence typing. Formerly classified as Staphylococcus aureus clonal complex 75, S. argenteus became a distinct species in 2015. Its identification has increased owing to widespread mass spectrometer use. Most East and Southeast Asian S. argenteus isolates reported to date are methicillin-susceptible, consistent with the susceptibility pattern of the isolate in our study. Given the potential equivalence in virulence between S. argenteus and S. aureus, we recommend treating S. argenteus with the same rigor as S. aureus until further clinical data becomes available.