PSEUDOMONAS-AERUGINOSA INFECTION IN CYSTIC-FIBROSIS - BACTERICIDAL EFFECT OF SERUM FROM NORMAL INDIVIDUALS AND PATIENTS WITH CYSTIC-FIBROSIS ON P AERUGINOSA STRAINS FROM PATIENTS WITH CYSTIC-FIBROSIS OR OTHER DISEASES

Abstract

P. aeruginosa strains originating from the respiratory tract of patients with cystic fibrosis (CF) and patients with other diseases (non-CF) were analyzed with regard to their sensitivity to the bactericidal activity of human serum. P. aeruginosa strains isolated from CF patients were more sensitive than strains from non-CF patients to the bactericidal activity of normal human serum. The bactericidal activity was heat labile. As regards the sensitivity to normal human serum, mucoid and non-mucoid variants did not differ. Strains originating from chronically infected CF patients with many precipitins against these bacteria did not differ with respect to serum sensitivity from strains originating from intermittently colonized CF patients without P. aeruginosa precipitins. Compared with normal sera, CF sera showed similar or higher bactericidal activity against a panel of P. aeruginosa strains. In this respect, any difference between CF sera with precipitins and CF sera without precipitins against P. aeruginosa was not found. Sera from 3 CF patients chronically infected with P. aeruginosa, and with many precipitins against these bacteria, showed a selective inability in bactericidal activity against the patients'' own P. aeruginosa isolate, possibly reflecting the presence of bactericidal blocking antibodies.