Effects of Growth Conditions and Pretreatment on the Iodine and Chlorine Susceptibility of Mucoid and Non-Mucoid P. aeruginosa

To compare the disinfection susceptibility of mucoid and non-mucoid P. aeruginosa in relation to EPS production, cultures were grown to stationary phase in defined media with a high or low C/N ratio using glucose as carbon source. Cultures diluted with phosphate buffered water pH 7.2 were pretreated by vortexing, centrifuging, or blending with 10 mM EDTA in PBW before disinfection with iodine, chlorine or monochloramine. It is suggested that differences observed between disinfectants may be due to their reactivities with cell constituents or modes of action. EPS may play a significant role in bacterial resistance to iodine and other halogens, although susceptibility varies markedly in relation to nutrient status and sample treatment before disinfection.