Vibrio cholerae  is the causative agent of the acute water-born diarrhoeal disease cholera. It  causes a diagnostic ‘rice water’ stool leading to dehydration and death . There are >200 O-serogroups of V. cholerae with only O1 and O139 causing pandemic outbreaks of cholera.  Each pre-existing pandemic strain is replaced by new diverse strains indicating rapid evolution in this species. Lateral gene transfer (LGT) is a major driving force of this strain evolution. So much so, that 20% of its genome shows evidence of recent gene transfer. In the environment, V. cholerae is subjected to a host of survival pressures and stimuli that facilitate LGT, including predation from bacteriophages and growth on the chitinaceous aquatic organisms. Non-O1/O139 strains are known to cause non-cholera diarrhoea, despite lacking ctxAB and tcp; the genes required cause cholera symptoms. The type III secretion system (T3SS) is the only known mechanism attributed to non-cholera diarrhoea. However, a recent study of Sydney non-O1/O139 strains have been shown to cause disease despite lacking all three virulence factors, indicating the presence of unknown virulence genes. Many genes have been identified in acid resistance but little is known about the ability of V. cholerae to resist bile salts (BSa) in the human gut. The environmental V. cholerae strain S18 (lacking the three virulence factors), shown to cause disease, was subjected to transposon mutagenesis and screened for Bsa sensitivity. Putative Bsa sensitive mutants were rescreened several times in which their ability to grow on BSa varied. Surprisingly, the wild-type also varied in its ability to grow on BSa, indicating the screen is inappropriate for the identification of genes involved in conferring resistance to BSa. Thus, it is hypothesised that multiple genes are involved for growth on BSa, and the organism may utilise different BSa resistance mechanisms when challenged with Bsa.