A novel mucin-sulphatase activity found in Burkholderia cepacia and Pseudomonas aeruginosa

Lung infections due to Burkholderia cepacia and Pseudomonas aeruginosa in p atients with cystic fibrosis (CF) are common, are associated with respirato ry morbidity and are a cause of mortality: Respiratory mucin in CF patients is highly sulphated, which increases its resistance to bacterial degradati on. Desulphation increases the susceptibility of mucin to degradation by ba cterial glycosidases and proteinases, and subsequent deglycosylation may fa cilitate bacterial colonisation by increasing available substrates and bind ing sites. This study determined whether clinical and environmental strains of B. cepacia and P. aeruginosa had the ability to desulphate mucin. Mucin -sulphatase activity was tested by incubating bacterial cell suspensions wi th S-35-sulphated mucins purified from LS174T and HT29-MTX human colon carc inoma cell lines. These mucins were also used to test for differences in su bstrate specificities. Mucin-sulphatase activity was detected in all nine B . cepacin strains and in four of six P. aeruginosa strains. There was strai n variability in the level of mucin-sulphatase activity. Aryl-sulphatase ac tivities of Pseudomonas isolates (determined with methylumbelliferyl sulpha te) were c. 20-fold higher than those of B. cepacia strains, and were indep endent of mucin-sulphatase activity, This is the first report to demonstrat e desulphation of mucin by B. cepacia and P. aeruginosa. It is concluded th at B, cepacin and P. nerIrginosa produce one or more cell-bound glycosulpha tase(s),in addition to aryl-sulphatase activity. Mucin-sulphatase activity of B. cepacia and P. aeruginosa may contribute to their association with ai rway infections in patients with cystic fibrosis.