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.

P. aeruginosa strains originating from the respiratory tract of patients with cystic fibrosis (CF) and patients with other diseases (non-CF) were analysed 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 heatlabile. As regards the sensitivity to normal human serum, mucoid and non-mucoid variants were not found to 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. aeurginosa was not found. Sera from three 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.

Antibodies against Pseudomonas aeruginosa in serum from normal persons and patients colonized with mucoid or non-mucoid Pseudomonas aeruginosa: Results obtained by crossed immunoelectrophoresis.

Serum from 154 normal persons was investigated for precipitating antibodies against P. aeruginosa by crossed immunoelectrophoresis, using a polyvalent P. aeruginosa standard antigen. Ninety-four per cent of the sera contained no demonstrable precipitins, and 6% contained precipitins against only one P. aeruginosa antigen. Thirty-four per cent of sera from 122 patients colonized with P. aeruginosa in various anatomical regions contained precipitins against 2 to 41 P. aeruginosa antigens. Serum from 14 patients harbouring mucoid strains of P. aeruginsa contained precipitants against these bacteria, and the average number of precipitins was significantly higher than the average number of precipitins in serum from patients harbouring non-mucoid strains. The largest number of precipitins was found in serum from adult patients chronically colonized with mucoid P. aeruginosa in the lower respiratory tract, and from adult patients with P. aeruginosa bacteremia originating from suppurative urinary tract infections caused by mucoid strains. Serum from patients with P. aeruginosa cystitis or from patients with P. aeruginosa colonization of the middle ear or with wound infection, contained only few or no precipitins.

Pseudomonas aeruginosa infection in cystic fibrosis. Relative prevalence of antibodies in serum against cathodic and anodic migrating P. aeruginosa antigens determined by immunoelectrophoretic methods.

Sera from 119 patients with cystic fibrosis were examined for precipitating antibodies against anodic migrating P. aeruginosa antigens by means of crossed immunoelectrophoresis. The presence of precipitins against cathodic migrating P. aeruginosa antigens was investigated by means of classical immunoelectrophoresis. Thirty-six per cent of the sera contained precipitins against both anodic and cathodic antigens, 20% contained only precipitins against anodic antigens, none contained only precipitins against cathodic antigens, and 44% had no demonstrable P. aeurginosa precipitins. The amount of extra information obtained by combining the results of classical immunoelectrophoresis with the results of crossed immunoelectrophoresis was small.

Crossed immunoelectrophoretic analysis of Bordetella pertussis antigens and of corresponding antibodies in human sera.

Fourty-four antigens were demonstrated in sonicated preparations of Bordetella pertussis (B.p.), using crossed immunoelectrophoresis against antiserum obtained from rabbits. No qualititative differences between the four strains of the Danish pertussis vaccine were found. In preparations of B.p. culture medium, purified with respect to Lymphocytosis Promoting Factor (LPF) activity, one antigen was possibly related to LPF. In human sera, antibodies against five of the B.p. antigens were demonstrated by means of crossed immunoelectrophoresis with intermediate gel. Antibody production was demonstrable in children during the pertussis vaccination period and was most marked after the second vaccination.

Staphylococcus aureus in cystic fibrosis: antibiotic sensitivity and phage types during the latest decade. Investigation of the occurrence of protein A and some other properties of recently isolated strains in relation to the occurrence of precipitating antibodies.

During the recent decade, 1651 isolates of Staphylococcus aureus from 111 patients with cystic fibrosis have been tested for antibiotic sensitivity and half of the isolates have been phage typed. All the patients were followed in one clinic and the policy of antibiotic treatment was consistent during this period. The results show a dynamic situation where "epidemic" phage types during recent years have been gradually replaced by other types and, during the same period, the prevalence of strains resistant to more than one antibiotic decreased. Multiresistant strains including strains resistant to methicillin were infrequent in these patients. From 23 per cent of the patients, the same strains were repeatedly isolated for more than 1 year despite an apparently successful chemotherapy. Recently isolated strains were found to produce cellbound as well as extracellular protein A. Ninety-one per cent of the strains produced extracellular lipase and only 8 per cent were resistant to mercury chloride. Eighty-one per cent of the patients produced precipitating antibodies agains S. aureus as judged by crossed immunoelectrophoresis. The investigated properties of S. aureus were not significantly correlated with the occurrence of precipitating antibodies against these bacteria. The possible significance of protein A in the pathology of the respiratory tract infection is discussed.