The role of methylparaben as an environmental contaminant in enhancing the pathogenicity of drinking water bacteria

Parabens, commonly used as preservatives in personal care products, can affect drinking water (DW) environmental microbial communities, posing an emerging global concern for public health. This study examines the impact of MP at 15 µg/L on the virulence of Acinetobacter calcoaceticus and Stenotrophomonas maltophilia both isolated from a drinking water distribution system (DWDS). MP was able to change the production and properties of bacterial released outer membrane vesicles (OMVs) by affecting the OMVs hydrodynamic size, lipid content and OMVs concentration. Furthermore, MP exposure increased the ability of A. calcoaceticus cells to invade human gingival fibroblasts (HGF). These findings highlight how MP can amplify interconnected virulence mechanisms - including OMV production, and host cell invasion - posing potential health risks in DWDS.