Physiological aspects of disinfection resistance in Pseudomonas cepacia.

A Pseudomonas cepacia population was isolated which had reduced susceptibility to iodine and maintained resistance when subcultured several times in phosphate buffer. This population was also resistant to iodine after growth in a minimal medium containing glycerol but not glucose. Addition of cAMP to glucose-grown cells caused increased resistance to iodine. Iodine-resistant cultures also demonstrated reduced susceptibility to chlorination but not to heat or metals (Cu/Ag). The results indicate that halogen resistance can be expressed in varying degrees, dependent on the carbon source, and cAMP may promote this expression. Thus, a catabolite repression-like mechanism may cause resistant cultures grown in some media to become more sensitive to halogens.