Antiviral Activity of Marine Bacterium Paraliobacillus zengyii Against Enterovirus 71 In Vitro and In Vivo

Enterovirus 71 (EV71) is the major causative agent of hand, foot, and mouth disease (HFMD), leading to a serious health threat to young children. Probiotics are effective at treating or preventing gastrointestinal infections, especially viral infections. Probiotics against EV71 are mainly traditional lactic acid-producing bacteria, and most of them have been proven to be effective only in vitro. Here, we report that the marine bacterium <i>Paraliobacillus zengyii</i> X-1125 (<i>P. zengyii</i>) has promising anti-EV71 activity. The antiviral effect of <i>P. zengyii</i> against EV71 was assessed in different cell lines, and the viral RNA levels and titers were obviously reduced after treatment with <i>P. zengyii</i>. Furthermore, we established an EV71-infected mouse model to evaluate its antiviral efficacy in vivo. The oral administration of <i>P. zengyii</i> significantly decreased the viral loads in the hindlimb muscles, spleens, and ileums. Further research revealed that <i>P. zengyii</i> enhances the expression of type I interferon (IFN-I) in EV71-infected cells. Similarly, transcriptome analysis indicated that the expression of interferon-stimulated genes (ISGs) in EV71-infected mice significantly increased after <i>P. zengyii</i> treatment. Taken together, the results of this study indicated that <i>P. zengyii</i> markedly reduces EV71 infection by regulating the IFN response both in vivo and in vitro, providing a potential means to work against EV71 infection.