Distinguishing Shewanella seohaensis

Shewanella is an environmentally ubiquitous genus with significant roles in bioelectrochemical applications and human infections. However, identification problems involving Shewanella putrefaciens, Shewanella xiamenensis, and Shewanella seohaensis, have been reported, potentially hindering research progress in these areas. In this study, we explore how to discriminate between these species. By comparing the genomes of Shewanella spp. available in public databases with that of the newly sequenced strain DSM9451, we show that this strain is a member of the S. seohaensis species. From the eight public genomes associated with this species, only two were correctly identified in public databases. Phenotypic analysis revealed distinct features of S. seohaensis relative to S. putrefaciens and Shewanella decolorationis. However, only differences in reaction intensity were observed between S. xiamenensis and S. seohaensis. To explore the finer relationships between isolates, a whole-genome multilocus sequence typing (wgMLST) schema was developed. This schema distinguished closely related species and revealed significant diversity among S. seohaensis and S. xiamenensis isolates, suggesting that both species may harbor isolates with significantly different metabolic properties. The identification of exclusive genes of each species enabled the design of a molecular method to differentiate S. seohaensis from closely related species, which will help in clarifying its role in human infections and environmental processes.