• In a targeted screen for V. cholerae virulence factors in a D. melanogaster model of oral infection, we discovered that, when delivered in LB broth, V. cholerae mutants defective in synthesis of the biofilm exopolysaccharide VPS killed flies significantly more slowly than WT V. cholerae ( Fig. 1 A ). We hypothesized that VPS might be required for colonization of the fly intestine. (pnas.org)