Novel anti-herpes simplex activity of Chryseobacterium indologenes: Genomic and metabolomic insights

Herpes simplex virus (HSV) is a pathogenic virus responsible for various diseases, necessitating alternative antiviral strategies for HSV-1 treatment. Given the antiviral properties of lactic acid (LA), we screened rhizobacteria from the maize (Zea mays L.) rhizosphere for organic acid production. Among the isolates, SR50, SR126, and SR135 exhibited significant LA production, confirmed by High-Performance Liquid Chromatography (HPLC) analysis. Their antiviral efficacy against HSV-1 was evaluated by determining IC₅₀ values and selectivity indices (SI = CC₅₀/IC₅₀), with SR50, SR126, and SR135 displaying SI values of 135.14, 10.74, and 2.17, respectively. SR50, identified via 16S rRNA sequencing as Chryseobacterium indologenes, was selected for further antiviral analysis. The cell-free supernatant (CFS) of SR50 demonstrated 73.3 % inhibition of viral adsorption, 60 % virucidal activity, and a 46.7 % reduction in viral replication. Metabolomic profiling using Gas Chromatography-Mass Spectrometry (GC-MS) identified short- and long-chain organic fatty acids. Whole Genome Sequencing (WGS) revealed a 4,581,372 bp genome encoding diverse biosynthetic pathways, including siderophores, plant hormones, terpenoids, polyketides, and other bacterial secondary metabolites. Additionally, genes encoding lactaldehyde dehydrogenase and pyruvate dehydrogenase confirmed the presence of lactic and acetic acid biosynthesis pathways. This study presents the first report of C. indologenes SR50 exhibiting anti-HSV-1 activity, highlighting its potential as a novel antiviral resource.