It is frequently difficult to determine the pathogenicity of Pseudomonas aeruginosa even when they are isolated from the patients, because of the probable “colonization”. One of the criteria to differentiate the “colonization” from the “infection” is isolation of the organism continuously for prolonged period. Such kind the approach is very time-comsuming and unpractical in the clinical medicine. Therefore, immunological analysis to evaluate chronicity of the infection were carried out in clinical subjects and experimentally infected animals.
The study was composed of the agar-gel precipitation test (Ouchterlony) between sera of patients and “Cell-sap antigens” and the indirect hemagglutination (OEP-IHA) test between sera from the patients and original endotoxin protein.
“Cell-sap antigens” were prepared by ultrasonic destruction of Pseudomonas aeruginosa. Original endotoxin protein for OEP-IHA test was supplied from Institute of Medical Science, University of Tokyo. Results of both tests were analysed correlating with clinical signs and findings such as number of colonies of Pseudomonas aeruginosa in the culture plate, duration (of the period) yielding organism in clinical materials, amount of sputum expectorated per day, values of ESR, CRP test and WBC in the blood and administration of steroid hormones.
Following results were obtained.
1. In sera of 30 normal human subjects studied as the control group, the precipitating antibodies against the “Cell-sap antigens” were not detected.
2. In 36 patients in whom Pseudomonas aeruginosa was isolated from clinical materials such as sputum, urine, blood and pus from infected decubitus, the precipitating antibodies were found in sera of 24 patients (64%). The highest positive result (74%, 20 out of 27 patients) was obtained in the patients of respiratory disease in whom the organisms were isolated in the sputum.
3. In patients in whom the organisms were continuously found in the sputum, the precipitating antibodies were detectable in sera of 18 out of 22 patients, and in patients in whom the organisms appeared in the sputum or urine transitorily, the test was negative, no matter whether they were numerous or few.
4. The high positive rate of the agar-gel precipitin test was obtained in correlation with the amount of sputum expectorated per day.
5. Number of WBC in the blood, CRP positiveness and ESR were not directly correlated with the positive rate of the test.
6. The administration of steroid hormones gave no obvious influence on the results of the test.
7. The precipitating antibodies were confirmed in the sera of the rabbits infected with the organisms by intratracheal instillation.
8. The correlative result between the agar-gel precipitin test and OEP-IHA test was simultaneously shown.
From these results, it is suggested that the agar-gel precipitin test using “Cell-sap antigens” produced from Pseudomonas aeruginosa is applicable to differentiate the patients who were under prolonged (and continuous) infection of the Pseudomonas aeruginosa from those in whom the organisms were found transitorily.
The test is considered to be useful in clinical analysis of Pseodmuonas aeruginosa infection.