Pseudomonas aeruginosa and cystic fibrosis: intrastrain variability in relation to intensity of immune response and clinical outcome.

Over periods exceeding two years, 63 Pseudomonas aeruginosa strains isolated from three children with cystic fibrosis were characterized using a 154 character auxanogram. Numerical analysis was carried out to establish intrastrain variability in relation to intensity of immune response and clinical outcome. For two patients, strains segregated in two distinct phenons. For the last patient, strains did not cluster. The degree of intrastrain variability during the infection was correlated with an increasing number of precipitins and with an unfavorable clinical outcome. This would suggest that strains which have a singular potential for antigenic variability are more likely to promote a host-bacteria conflict.