Colonization competition and complementary assays of V. cholerae strains on turtle body surfaces. Competition indexes were measured at different sites on the soft-shelled turtles' body surfaces. Colonization competition and complementary assays for mshA (A), gbpA (B), and tcpA (C) strains. The y axis represents log values of the competitive index [mutants/VC4251dlacZ or complementation strains/VC4251dlacZ(pBAD)]. Bars with different colors indicate competitive indexes for different competition pairs. For the mshA gene competition and complementary assays, the results always showed statistically significant differences (day 0 to day 10, regardless of carapace, calipash, or limbs; all P < 0.05 by t test). For the gbpA and tcpA genes, no competition pairs showed significance (all P > 0.05).