ABSTRACT
Isolated bacteria from respiratory infectious diseases were collected in cooperation with institutions located throughout Japan, since 1981, and Ikemoto et al. have been examining sensitivities of the isolates to various antibacterial agents and antibiotics, relationships between the isolates and the backgrounds of the patients and so forth each year. We report here the research results for the year 1988. In 18 institutions around the entire Japan from October 1988 to September 1989, 554 strains of bacteria were isolated mainly from the sputa of 439 patients with respiratory infectious diseases and assumed to be the etiologic bacteria. MICs of various antibacterial agents and antibiotics against 68 strains of Staphylococcus aureus, 102 strains of Streptococcus pneumoniae, 120 strains of Haemophilus influenzae, 86 strains of Pseudomonas aeruginosa, 65 strains of Branhamella catarrhalis, 18 strains of Klebsiella pneumoniae and so forth, were determined, and the drug sensitivities of these strains were examined except for the strains which died during transportation. The drug sensitivities of the main strains were almost the same as those determined last year for each drug. However, S. aureus strains for which MICs of methicillin were higher than 12.5 micrograms/ml (methicillin-resistant S. aureus) accounted for 38.2%, and the frequency of drug resistant bacteria increased over last year's 18.2%. Also, we examined changes in the backgrounds of patients, the infectious diseases, and the etiologic bacteria and so forth. As to patient backgrounds, there were many infectious diseases found in a high age bracket, and the patients over age 60 accounted for 57.2% of the diseases. In the distribution by disease, bacterial pneumonia and chronic bronchitis accounted for greatest numbers of cases 32.1% and 31.4%, respectively, followed by bronchiectasis and bronchial asthma. As for frequencies of etiologic bacteria by disease, S. aureus (22.5%) and S. pneumoniae (15.4%) in pneumonia, S. pneumoniae (25.7%) and H. influenzae (24.1%) in chronic bronchitis, H. influenzae (32.5%) and P. aeruginosa (23.8%) in bronchiectasis, and H. influenzae (31.4%), S. pneumoniae and B. catarrhalis (20.0%) in bronchial asthma were the most frequent. Regarding effects of administration of antibiotics and isolates obtained on each day after infection, those bacteria which were isolated before antibiotic administration and which decreased after administration included S. pneumoniae, H. influenzae, and B. catarrhalis. Frequencies of S. aureus and P. aeruginosa, however, increased after antibiotic administration. Also, when dosing continued for more than 15 days, the frequency of P. aeruginosa increased rapidly.
