Freshwater Microbiomes Shape Viral Inactivation in Continuous Cultures

Enteric viruses present a heightened risk of waterborne transmission due to their high stability in freshwater ecosystems. While bacteria have been known to aid in viral removal and inactivation in aquatic environments, the impact of community diversity on viral inactivation across freshwater sources remains underexplored. To investigate this, researchers generated 64 unique freshwater communities from three lakes and three aquifers, subsequently placing each community within chemostat cultures.

These communities were then subjected to challenges involving two viruses: coxsackievirus B5 and human adenovirus 2. The findings revealed that both viruses exhibited a faster rate of inactivation in lake-derived communities as opposed to groundwater-derived ones. Notably, adenovirus proved to be more susceptible to inactivation compared to coxsackievirus under both freshwater conditions.

The researchers employed community-level parameters, such as cell numbers, richness, and evenness, to predict viral inactivation; however, these parameters did not prove to be significant predictors. Instead, differential abundance analyses identified specific bacterial taxa associated with the inactivation process. Acidovorax sp. emerged as a common association across all sources, while Brevundimonas sp., Sphingopyxis sp., and Hydrogenophaga sp. demonstrated source-specific associations.

These discoveries offer fresh insights into the ecological factors influencing viral stability, suggesting that viral inactivation may hinge more heavily on particular microbial taxa and their ecological context rather than the overall community diversity. Uncovering these associations enhances our comprehension of the driving forces behind viral persistence in freshwater environments.