Mucoid Pseudomonas aeruginosa in cystic fibrosis

The relative importance of mucoid Ps. aeruginosa, non-mucoid Ps. aeruginosa and absence of Ps. aeruginosa as indicators of the severity of lung disease was assessed in 82 age matched children and adolescents with cystic fibrosis. Both Shwachman score and forced expiratory volume in one second (FEV1) were significantly lower in subjects whose sputa yielded mucoid strains than in those whose sputa had no Ps. aeruginosa or those with non-mucoid forms. Furthermore 29 of 32 patients (91%) with a Shwachman score below 80 and 31 of 37 (84%) with a FEV1 of less than 75% predicted had one or more positive cultures for mucoid Ps. aeruginosa. While identification of mucoid forms of Ps. aeruginosa in the respiratory tract of children and adolescents with cystic fibrosis is an unfavourable factor, non-mucoid forms appear to be of no major significance.