Identification and characterization of a marine bacterium extract from Mameliella sp. M20D2D8 with antiviral effects against influenza A and B viruses

Abstract

Abstract Despite of significant improvement in vaccines and chemotherapeutic drugs, infectious RNA viruses have still wreaked the largest havoc on global economy and caused a severe threat to animal and human health by emerging and re-emerging outbreaks. To curb the challenge of viral adaptation and evolution, continued and increased vigilance will be required. Particularly, antiviral drugs derived from a new, natural sources provide an attractive strategy for controlling problematic viral diseases. In this antiviral study, we discovered a previously unknown bacterium, Mameliella sp. M20D2D8, by conducting a thorough antiviral screening of marine microorganisms. M20D2D8 extract exhibited a remarkable antiviral activity with great safeness and effectiveness against broad-spectrum infections of influenza virus A/PR8 (IC50 = 2.93 µg/mL, SI = 294.85), A/Phil82 (IC50 = 1.42 µg/mL, SI = 608.38) and B/Yamagata (IC50 = 1.59 µg/mL, SI = 543.33) in vitro. After comparative study of pre, co- and post-treatment, the antiviral action was found to be associated with post-entry stages of viral replication. Particularly, M20D2D8 extract suppressed viral replication by enhancing apoptosis-mediated host immune reaction. Moreover, it efficiently suppressed viral genome replication, protein synthesis and infectivity, resulting in successful protections in two different cell lines of MDCK and A549 cells. Collectively, our findings highlight the identification of antiviral capabilities within a remarkable marine bacterium, potentially serving as a crucial element in future drug development for the control of viral diseases.