[Molecular diagnosis in respiratory infections].

Recent advance in molecular biology has enabled the specific and rapid diagnosis of the various infectious diseases. Though we commonly use the three major diagnostic procedure as isolation of the pathogen, direct detection of the pathogen and measurement of the immunological host reaction, DNA probe method would be the fourth major procedure in the clinical microbiology. The indication of the DNA probe method would be considered in the four cases as follows, 1. necessity of the special equipment to isolate the pathogen, 2. necessity of the long period to isolate the pathogen, 3. existence of the cross reaction among the pathogen and relative organisms in the immunological procedure, 4. existence of the difficulty to identify the species of the pathogen by the ordinary procedure. When we consider those indications, Legionnaires' disease might be one of the typical infectious disease to show the benefits of the DNA probe method in diagnosis. So far two types of DNA probe kits for Legionnaires' disease are available. One is the genus specific direct detection kit from the clinical specimens (Gen-probe), and the other is the microplate hybridization kit to identify each species of Legionella. The results of the evaluations of both kits showed the high specificity, rapidity and the clinical usefulness. In the next few years, various types of DNA probe kits might be newly developed and the contribution of those in the clinical microbiology would be much more than we expected.