Bacterial Survival in Dictyostelium.

We performed an assay to test the ability of different E. coli strains to survive inside amoebal cells after ingestion. In the assay we incubated bacteria together with cells of Dictyostelium discoideum for six hours. After co-incubation most of the uningested bacteria were removed by centrifugation and the remaining uningested bacteria were killed by gentamicin. Gentamicin is used because it does not penetrate into eukaryotic cells allowing the ingested bacteria to survive the antibiotic treatment, whereas bacteria outside the amoebal cells are killed.