It has long been speculated that V. cholerae has evolved mechanisms
to kill bacterial competitors. Chakrabarty et al. identified
11 diffusible bacteriocins with toxicity toward the enteric bacteria
Escherichia coli, Shigella sonnei, and Shigella flexneri (15). However,
expression of such bacteriocins and mechanisms underlying
their antimicrobial properties are not well understood. Thus, we
investigated whether the T6SS contributes to the antimicrobial
properties of V. cholerae. Interbacterial virulence was determined
by exposing bacterial prey (the organism that is attacked) to
a bacterial predator (a V. cholerae strain that is attacking) and
measuring the survival of bacterial prey. Here, we present experimental
evidence to demonstrate the antimicrobial properties
of the V. cholerae T6SS. We propose that interbacterial toxicity
promotes V. cholerae survival in the environment and/or during
colonization of a host.