SUSCEPTIBILITY OF BACTERIA ISOLATED FROM THE PATIENTS WITH LOWER RESPIRATORY TRACT INFECTIONS TO ANTIBIOTICS (1986)

Enlisting the help of various research institutions across the nation, IKEMOTO et al. have been pooling cultures of clinical isolates of respiratory tract infections and mapping out the correlations between patient backgrounds and the causative bacteria and the changes in the sensitivity spectra of the bacteria to various antibacterial and antibiotic agents annually since 1981. The following is a report of the 1986 findings. During the period from September, 1986 to March, 1987, 558 cases of respiratory infections were reported at 17 institutions across the nation and a total of 657 apparent causative strains were isolated from sputum samples. Of these strains, 75 strains of Staphylococcus aureus, 108 of Streptococcus pneumoniae, 150 of Haemophilus influenzae, 107 of Pseudomonas aeruginosa (non-mucoid production type), 21 of P. aeruginosa (mucoid production type), 32 of Klebsiella pneumoniae, 8 of Escherichia coli, and 55 of Branhamella catarrhalis were subjected to MIC determination of various antibacterial and antibiotic agents to map drug sensitivities. In addition, diagnoses, age distributions by diagnoses, frequencies of infectious diseases, types of isolated bacteria, and usage statuses of the antibacterial and antibiotic agents the times of at isolation were also investigated. MIC determinations were carried out to investigate susceptibilities of causative organisms of respiratory tract infections to various antibacterial and antibiotic agents. From the 558 cases of respiratory tract infections, 657 strains were detected at concentrations not less than 104-6/ml and identified to be the causative organisms. Of these strains, 603 could be used for MIC determination. An overwhelming majority of major causative bacteria, inclusive of H. influenzae and S. pneumoniae, showed sensitivity patterns similar to the sensitivity patterns found a year earlier. P. aeruginosa alone, however, showed some increase in its susceptibility to penicillin and cephem antibiotics. Regarding patient backgrounds, the age distribution was heavily biased towards the higher end of the scale, which patients with ages of 50 or higher accounting for 77.9%, compared to 73.5% in 1985. When the patients were classified by diagnoses, chronic bronchitis, bacterial pneumonia and bronchiectasis accounted for the majority of the infections: 28.7%, 23.3%, and 19.0%, respectively. The percentages of chronic bronchitis and bacterial pneumonia 28.7% and 23.3%, respectively, were somewhat higher