Simultaneous and Sequential Coexposures of Serratia marcescens in Caenorhabditis elegans

Coinfections are common in nature and include hosts simultaneously or sequentially exposed to different genotypes. We investigated the potential for simultaneous and sequential exposures to impact host fitness by exposing Caenorhabditis elegans hosts to different bacterial strains of Serratia marcescens . We found that in simultaneous exposures a highly virulent strain induced high mortality regardless of coexposure. In sequential exposures, the same highly virulent strain induced high mortality if it was the first strain introduced in a coexposure. Overall, we find host outcomes after coinfections may depend on particular parasite genotype combinations and infection timing.