Prevalence of mucoid strains of Pseudomonas aeruginosa in bacteriological specimens from patients with cystic fibrosis and patients with other diseases.

The relative prevalence of mucoid strains compared with non-mucoid strains of Pseudomonas 
aeruginosa has been investigated in all routine bacteriological specimens received in 
a department of clinical microbiology during 1973. Pseudomonas aeruginosa was isolated 
from 1054 of the specimens (5.7 per cent) representing 53 patients 
with cystic fibrosis (551 isolates) and 169 patients with other diseases 
(503 isolates). The relative prevalence of mucoid strains was significantly higher 
in specimens from patients with cystic fibrosis (80 per cent) than 
in specimens from patients with other diseases (3 per cent). Considering 
patients without cystic fibrosis, the relative prevalence of mucoid strains was 
low in specimens from all anatomical regions, and no special preference 
of these strains for the respiratory tract could be demonstrated in 
these patients, in contrast to the situation in patients with cystic 
fibrosis. Alternation between mucoid strains and non-mucoid strains in subsequent specimens 
was observed in 33 of the patients. 