Haemophilus from the lower respiratory tract of patients with cystic fibrosis.

Fifty-six non-haemolytic Haemophilus strains were isolated during current bacteriological examinations from material 
from the lower respiratory tract of 39 patients with cystic fibrosis 
during a 6- month period. Except for six strains which belonged 
to Haemophilus parainfluenzae, all strains were identified as Haemophilus influenzae. Biotype 
I of H. influenzae was the predominating taxon (38%) and was 
especially related to patients with recurrent or prolonged colonization. Only two 
strains were capsulated. An unexpectedly high percentage of the strains produced 
lysine decarboxylase. The significance of this property in the pathogenesis of 
the respiratory tract colonization is discussed. 