Rapid Diagnosis of Respiratory Pseudomonas Infections: Indirect Immunofluorescent-staining of Sputum with Monoclonal Antibody to Pseudomonas aeruginosa

For the rapid diagnosis of respiratory infections caused by Pseudomonas aeruginosa, we developed IFA-staining of sputum for Pseudomonas aeruginosa using serogroup-specific monoclonal antibody (MEIASSEI RYOKUNOUKIN, MEIJI, JAPAN). IFA-titers of each serogroup-specific antibodies were distributed from 1: 4 to 1: 200 dillution, and minimal concentration of bacteria detectable by IFA-staining was 106 CFU/ml in the sputum. We performed IFA-staining on 131 smears of the sputa presented to the Clinical Laboratory of Nagasaki University. In 36 specimens from which more than 106 CFU/ml of Pseudomonas aeruginosa were isolated, 27 specimens (75%) were judged as IFA-positive, and in 18 specimens with more than 107 CFU/ml of Pseudomonas aeruginosa, 15 (83%) were IFA-positive. Furthermore, there was a distinct correlation between number of fluorescing bacilli (microscopic findings of IFA-staining) and quantity of Pseudomonas aeruginosa isolated from the sputum. In the 86 sputa with a negative culture for Pseudomonas aeruginoas, 82 (95%) were judged as IFA-negative. Using this method, we can directry identify Pseudomonas aeruginosa in the sputum, and according to these results, the IFA-staining of the sputum was considered to be a useful method for the rapid diagnosis of respiratory infections caused by Pseudomonas aeruginosa.