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.