[Susceptibilities of bacteria isolated from patients with respiratory infectious diseases to antibiotics (1995)]

The bacteria isolated from the patients with lower respiratory tract infections were collected by institutions located throughout Japan, since 1981. Ikemoto et al. have been investigating susceptibilities of these isolates to various antibacterial agents and antibiotics, and characteristics of the patients and isolates from them each year. Results obtained from these investigations are discussed. In 23 institutions around the entire Japan, 567 strains of presumably etiological bacteria were isolated mainly from the sputa of 459 patients with lower respiratory tract infections during the period from October 1995 to September 1996. MICs of various antibacterial agents and antibiotics were determined against 74 strains of Staphylococcus aureus, 82 strains of Streptococcus pneumoniae, 104 strains of Haemophilus influenzae, 85 strains of Pseudomonas aeruginosa (non-mucoid strains), 18 strains of Pseudomonas aeruginosa (mucoid strains), 52 strains of Moraxella subgenus Branhamella catarrhalis, 25 strains of Klebsiella pneumoniae etc., and the drug susceptibilities of these strains were assessed except for those strains that died during transportation. 1) S. aureus. S. aureus strains for which MICs of oxacillin (MPIPC) were higher than 4 micrograms/ml (methicillin-resistant S. aureus) accounted for 52.7%. Arbekacin (ABK) showed the most highest activity against S. aureus with MIC80 of 0.5 micrograms/ml. Vancomycin (VCM) showed the next highest activity with MIC80 of 1 microgram/ml. These drugs showed the high activities against MRSA with MIC80S of 1 microgram/ml. 2) S. pneumoniae. Most of drugs tested showed potent activities against S. pneumoniae. Imipenem (IPM) and panipenem (PAPM), carbapenems, showed the most potent activity with MIC80S of 0.063 microgram/ml. Cefotaxime (CTX), cefmenoxime (CMX) and cefpirome (CPR) of cephems showed the next most potent activities with MIC80S of 0.25 microgram/ml. Erythromycin (EM) and clindamycin (CLDM) showed low activities with MIC80S 128 micrograms/ml or high. Among these strains, however, 48.8% and 65.9% of respective strains were quite toward sensitive these agents with MICs of 0.063 microgram/ml. 3) H. influenzae. The activities of all drugs were potent against H. influenzae test with all MICs at 4 micrograms/ml or below. Cefotiam (CTM), CMX, cefditoren (CDTR) and ofloxacin (OFLX) showed the most potent activity with MIC90S to 0.063 microgram/ml. 4) P. aeruginosa. (mucoid strains) IPM and tobramycin (TOB) showed the most potent activity against P. aeruginosa (mucoid strains) with MIC80S of 1 microgram/ml. Ceftazidime (CAZ), cefsulodin (CFS) and carumonam (CRMN) showed next potent activity, with MIC80S of 2 micrograms/ml. The MIC80S of the other drugs ranged from 4 micrograms/ml to 32 micrograms/ml. 5) P. aeruginosa (non-mucoid strains). TOB and ciprofloxacin (CPFX) showed the most potent activities against P. aeruginosa (non-mucoid strains) with MIC80S of 1 microgram/ml. The MIC80 of ampicillin (ABPC) was 128 micrograms/ml in 1994, it was 16 micrograms/ml in 1995. 6) K. pneumoniae. All drugs except ABPC were active against K. pneumoniae. CPR and CRMN showed the most potent activities against K. pneumoniae with MIC80S of 0.063 microgram/ml. The MIC80S of the other drugs ranged from 0.125 microgram/ml to 2 micrograms/ml. 7) M. (B.) catarrhalis. Against M. (B.) catarrhalis, all the drugs showed good activities with MIC80S at 4 micrograms/ml or below. And MICs of all strains were 8 micrograms/ml or below. IPM, OFLX and minocycline (MINO) showed the most potent activity with MIC80S of 0.063 microgram/ml. Also, we investigated year to year changes in the characteristics of patients, their respiratory infectious diseases, and the etiology. Patients' backgrounds were examine for 567 isolates from 459 cases. The examination of age distribution found that the proportion of patients with ages over 60 years was 66.3% of all the patients showing a slight increase over that in 1994. Proportion of differe