A small microcin plays a big role in V. cholerae interbacterial competition.

Microcins are antibacterial small proteins secreted by gram-negative bacteria. In this issue of Cell Host & Microbe, Kim et al. report the discovery of a V. cholerae microcin, MvcC. MvcC shows antibacterial activity against non-self V. cholerae strains, which do not encode the cognate immunity protein.