Serotyping of Pseudomonas aeruginosa from patients with cystic fibrosis of the pancreas.

Serotyping of 30 mucoid strains isolated from cystic fibrosis patients was carried 
out by slide agglutination tests with both live and heat-killed cells 
and by tube agglutination test with heat-killed cells. Comparison of the 
results obtained by these 2 methods revealed that tube agglutination with 
heat-killed cells was the superior method. More than half the strains 
were found to be Homma's serotype 15 (group M in the 
new schema [2]). Slide agglutination with live cells did not give 
clear results: some strains showed occasionally positive or negative agglutinations against 
the same serotype serum. Changes in serotypes (groups in the new 
schema [2]) were found in some strains, although the number was 
very small. 