Some bacterial species form tough layers on surfaces, known as biofilms, as a means of self-protection. However, swimming subpopulations of a few bacterial species can penetrate biofilms, making them vulnerable to destruction.

Romain Briandet and his colleagues at the Micalis Institute in Jouy-en-Josas, France, report that a tiny proportion of certain Bacillus species can tunnel through biofilms, creating pores that allow molecules to flow in. Exposing Staphylococcus aureus biofilms — a common problem in hospitals and industrial settings — to bacilli swimmers and to an antimicrobial called benzalkonium chloride killed approximately 300 times more S. aureus than treatment with the antimicrobial alone.

Supplementing antimicrobial treatments with swimming bacilli could increase their efficacy, the researchers suggest.

Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1200791109 (2012)