Retrospective Analysis of Staphylococcus argenteus Isolated from Food-Related Specimens in Nagoya

Abstract

Staphylococcus argenteus, a novel species formally named in 2015 and distinct from Staphylococcus aureus, has a historical distribution that remains unclear. In this study, a total of 1,021 staphylococcal isolates collected from food-related specimens in Nagoya City between 1986 and 2022 were re-examined. Of these, 65 isolates (6.4%) were re-identified as S. argenteus. The earliest detection was in 1986, and the species has been identified in almost every subsequent year. These findings suggest that S. argenteus had already disseminated into food-related environments by the 1980s. Furthermore, the results indicate that most S. argenteus isolates have been correctly identified in recent years, due to improvements in current MALDI-TOF MS identification. Multilocus sequence typing (MLST) revealed ST2854 as the most prevalent sequence type (ST) in this study, while clinically important strains, such as ST1223 and ST2250, have been detected since the 1990s. The presence of novel and multiple STs with distinct PCR-based open reading frame typing (POT) types indicates that genetically diverse S. argenteus strains have been present in food-related environments since the 1980s. These results provide important insight into the historical background of S. argenteus and underscore the need for continued monitoring, particularly in food-related environments.