Extracellular neuraminidase production by a strain of Pseudomonas aeruginosa isolated from cystic fibrosis.

Extracellular neuraminidase production was found in a strain of Pseudomonas aeruginosa isolated from a patient with cystic fibrosis. Extracellular neuraminidase was secreted in growth medium during the early stationary phase. The enzyme was produced in brain-heart infusion supplemented with 10% colt serum. The enzyme hydrolyzed the alpha 2 leads to 3 glycosidic linkages from N-acetylneuraminlactose and fetuin, and cleaved also mucins from CF. Activity was optimal pH 6.6-7.0, not modified by addition of calcium and magnesium cations, and insensitive to EDTA inhibition (50% inhibition in the presence of 0.035 mM EDTA). The enzyme was stable at temperatures of 4 degrees C for weeks and 37 degrees C for at least 24 h but was almost completely inactivated within 30 min at 56 degrees C. No N-acetylneuraminic acid aldolase was secreted in growth medium. For the neuraminidase producing strain and non-producing reference strains for P. aeruginosa, we demonstrated an endogeneous neuraminidase acting on endogenous substrate from highly concentrated cell extracts.