Effect of oxygen limitation and starvation on the benzalkonium chloride susceptibility of Escherichia coli.

The effect of BAC on planktonic and sessile cells was investigated using the gfp-tagged E. coli K-12. Increasing temperature from 10C to 30C increased the bactericidal effect of BAC for starved and nonstarved E. coli under aerobic and anaerobic conditions. Decreasing cell densities increased the decay rate for BAC-exposed cells for starved and nonstarved E. coli. Biofilms of E. coli exposed to BAC in anaerobic medium showed a greater percentage of membrane-compromised cells than biofilms grown in aerobic medium. Image analyses of BAC-exposed biofilms showed that membrane- compromised cells were occasionally located in the interior structure of the biofilm microcolonies. J Appl Microbiol. 2008;105(5):1310-7.