The meiofauna as neglected carriers of antibiotic resistant and pathogenic bacteria in freshwater ecosystems

Abstract

The World Health Organization considers antibiotic resistance as one of the main threats to human and other animals? health. Despite the measures used to limit the spread of antibiotic resistance, the efforts made are not enough to tackle this problem. Thus, it has becomeimportant to understand how bacteria acquire and transmit antibiotic resistant genes (ARGs), in particular in the environment, giventhe close connection between the latter and human and animal health, as defined by the One-Healthconcept. Aquatic ecosystems areoften strongly impacted by anthropogenic activities, making them a source for ARGs and antibiotic resistant bacteria (ARB). Althoughfreshwater meiofauna have been the object of active research, few studies have focused on the relationship between the spread of an-tibiotic resistance and these organisms. In this review, we investigated freshwatermeiofaunaas carriers of resistances since they playa central role in the aquatic environments and can harbor human and animal potential pathogens. We assessed if these animals couldcontribute to the spread of ARGs and of potentially pathogenic bacteria. Only four taxa (Rotifera, Chironomidae, Cladocera, Copepoda)were found to be the subject of studies focused on antibiotic resistance. The studies we analyzed, although with some limitations,demonstrated that ARGs and ARB can be found in these animals, and several of them showed the presence of potentially pathogenicbacteria for humans and animals within their microbiome. Thus, meiofauna can be considered a source and a reservoir, even if neglected,of ARGs and ARB for the freshwater environments.However, further studies are needed to evaluate the impact of the meiofauna on thespread and persistence of antibiotic resistance in these ecosystems.