1. After 1965, gram negative bacteria were being detected more frequently. In propotion to this, Pseudomonas was detected more and more in clinical speciemens, but after 1973 it reached at a plateau or appeared to have somewhat downward tendency.
2. Annual changing patterns of the rate of antibiotics resistant strains were observed. Antibiotics sensitive strains by disc method are not always sensitive by the agar plate dilution method. Therfore, it is needed to pay attention to the antibiotics concentrations contained in the discs.
3. Some of gentamicin resistant strains are sensitive to new semisynthetic antibiotics (Apalcillin, Piperacillin, Mezlocillin, Cefsulodin).
4. In the autopsied cases, the most of isolated bacteria were gram negative rods and P. aeruginosa were detected in 19.5%.
5. The mean OEP-HA titer of autopsied cases was lower than that of outpatients.
