Detection of Pseudomonas aeruginosa Antigens in Sputum, Broncho-Alveolar Lavage and Concentrated Urine by Enzyme-linked Immunosorbent Assay

A sandwich enzyme-linked immunosorbent assay (ELISA) for detection of a 11 serotypes of P. aeruginosa has been developed by using polyclonal rabbit anti P. aeruginosa (NC-5 strain) antiserum. The following results were obtained: 1) Cultured broth of P. aeruginosa was detected most sensitively by this assay followed by sonicated soluble antigen, washed bacetrial fluid and heated soluble antigen of P. aeruginosa. The lower limit of detection was approximately 2.3 × 104 cfu/ml of P. aeruginosa (NC-5 strain) (containing 22.2 ng/ml of protein) in cultured broth. 2) By this assay, all serotypes of P. aeruginosa and some strains of Family Pseudomonadaceae (RNA group I) were detected, but no cross reaction was noticed to other species of bacteria (24 species, 268 strains). 3) The serum antigen in the experimental sepsis of P. aeruginosa or murine experimental pneumonia was detected when at least approximately 103 cfu/ml of P. aeruginosa was present in serum or BALF. But the antigen was detected from concentrated urine even under the concentration of 102 cfu/ml in sepsis. 4) P. aeruginosa antigens in sputum of patients with chronic respiratory tract infection was also detected. There was a significant difference between absorbance value of sputum in non-infected patients (group 1) and one in infected patients by P. aeruginosa (group 3) (p