緑膿菌感染症の研究

泌尿器科領域における臨床分離株と環境分離株に関する疫学的検討

抄録

1) P. aeruginosa has been consistently isolated from 26.5 to 42.4% of the patients with urinary tract infections in the urological ward of Okayama University Hospital for the past 7 years. 232 (22.3%) out of 1042 hospitalized patients were with urinary tract infections with P. aeruginosa for past 4 years. Of these, 149 (64.2%) were thought to be the catheter induced urinary tract infections. The mode of spreading of this organism was epidemiologically investigated.
2) The following three laboratory assays were used for identification of P. aeruginosa isolated from clinical and environmental strains; serological typing, antibiotic sensitivity and protease and elastase production. Serological typing with 13 immunodiagnostic sera (Toshiba Chemical Industry) was performed by slide agglutination method. Protease and elastase production were detected by the method described by Goto et al.
In combination with serological typing and antibiograms, protease and elastase production offers the finest means of differentiating the strains of P. aeruginosa.
3) Of 136 clinical strains of P. aeruginosa, 89.7% were serotypable strains. Serotype K was the most prevalent (36.0%), followed by serotype E (28.7%), F (10.3%) and A (7.4%). Most of serotype F and B which were concurrently isolated from patients in 1976 had the same patterns of antibiogram and production of protease and elastase. It was strongly suggested that these patients were nosocomially cross-infected with the P. aeruginosa from the catheterization or through instrumentation.
4) Of 354 environmental specimens, 78 P. aeruginosa (22.8%) were isolated, which were frequently isolated from floor mops and sink-drains. Of these strains, 87.2% were serotypable strains. Serotype E was the most prevalent (42.3%), followed by serotype K (24.4%) and B (12.8%). The same strains were seldom detected at the same sources successively, but different types of P. aeruginosa were usually detected. Among the serotypes E, F and K, 18 strains (23.1%) were identical with the clinical strains. All of these were found during or after the clinical outbreaks of P. aeruginosa infections. There was no environmental strains that caused clinical infections. The other 60 strains (76.9%) were different from the clinical strains, and present only transiently in the hospital environments.
5) Both clinical and environmental strains similary produced protease and elastase at 70 to 80%, hemolysin at 100%. Only 10 out of 37 environmental strains (27.0%) were found to produced exotoxin.