“…Bacterial colonization is probably promoted by the unique composition of the sputum, which contains mucin, lipids, proteins, amino acids, ions and DNA released by neutrophils in concentrations above the mean of a healthy individual (Barth & Pitt, 1996;Kilbourn, 1978;Sahu & Lynn 1978;Smith et al, 1988). Indeed, a number of studies have provided evidence for a correlation between individual sputum components and the emergence or stabilization of certain P. aeruginosa pheno-types (Govan, 1975;Ohman & Chakrabarty, 1982;Wang et al, 1996;Yoon et al, 2002).…”