Topical Microbial Therapeutics against Respiratory Viral Infections

• Published in: Trends in molecular medicine 2021-06, Vol.27 (6), p.538-553
• Main Authors: Spacova, Irina, De Boeck, Ilke, Bron, Peter A., Delputte, Peter, Lebeer, Sarah
• Format: Article
• Language: English
• Subjects: Animals; Gastrointestinal Microbiome; Humans; Immune System - drug effects; microbial therapeutics; microbiome; probiotics; Probiotics - therapeutic use; respiratory; Respiratory Tract Infections - drug therapy; Respiratory Tract Infections - immunology; Respiratory Tract Infections - virology; viral infection; virus; Virus Diseases - drug therapy; Virus Diseases - immunology; Virus Diseases - virology
• ISSN: 1471-4914; 1471-499X
• DOI: 10.1016/j.molmed.2021.03.009

Emerging evidence suggests that microbial therapeutics can prevent and treat respiratory viral diseases, especially when applied directly to the airways. This review presents established beneficial effects of locally administered microbial therapeutics against respiratory viral diseases and the inferred related molecular mechanisms. Several mechanisms established in the intestinal probiotics field as well as novel, niche-specific insights are relevant in the airways. Studies at cellular and organism levels highlight biologically plausible but strain-specific and host and virus context-dependent mechanisms, underlying the potential of beneficial bacteria. Large-scale clinical studies can now be rationally designed to provide a bench-to-bedside translation of the multifactorial bacterial mechanisms within the host respiratory tract, to diminish the incidence and severity of viral infections and the concomitant complications. Bacteria inhabiting or administered in the airways undergo multifactorial interactions with viruses and can serve as a double-edged sword by inhibiting or aggravating viral infections.Evidence from in vitro research and animal models suggests that microbial therapeutic application directly into the airways can effectively impact the susceptibility to and the course of respiratory viral disease.Clinical studies with microbial therapeutic formulations targeting the upper respiratory tract (URT) in humans document safety, temporary URT colonization, antibacterial activities, nasal barrier enhancement, and immunomodulation. Yet more documentation is needed on antiviral effects of microbial therapeutics in the URT.