[Recent trend of incidence of respiratory pathogenic bacteria and its susceptibility to antimicrobial agents: studies in the year 1984-1986].
Based on a quantitative analysis of sputum cultures, pathogenic bacteria in respiratory ailments isolated in our laboratory during 1984 to 1986 were classified and analyzed. During the study period, the most frequently isolated agent was Haemophilus influenzae followed by Pseudomonas aeruginosa, Branhamella catarrhalis and Streptococcus pneumoniae. They together consisted of 70 approximately 74% of all the respiratory pathogenic bacteria isolated in our study. Susceptibilities of above pathogens to antimicrobial agents were investigated using the agar dilution method. Results are summarized as follows. 1. Ratio of proportion of beta-lactamase producing strains among non beta-lactamase producing strains of H. influenzae markedly decreased in 1986 (6/70, 8.6%) as compared to previous years (11/73, 15.1% in 1984 and 8/49, 16.3% in 1985). In consequence, MIC90 values for penicillins reduced considerably in 1986. Among the antibiotics examined cefmenoxime (CMX) and cefotaxime (CTX) were the most active agents against H. influenzae. A development of resistance to other cephems and new quinolones (norfloxacin, ofloxacin, ciprofloxacin) was not evident during the 3-year survey. 2. Against S. pneumoniae, benzylpenicillin was still the most active agent despite gradual increase of frequency of isolation. Ampicillin (ABPC), piperacillin (PIPC), CMX and CTX were also potent against S. pneumoniae. S. pneumoniae were frequently isolated from patients treated with new quinolones or minocycline (MINO). This phenomenon may be explained by higher MIC values of these agents against S. pneumoniae. 3. Of B. catarrhalis strains isolated, more than 80% were beta-lactamase positive, although MIC90 were not so high (1.56 micrograms/ml for ABPC and 0.20 micrograms/ml for PIPC). Among the antibiotics tested, latamoxef was the most active agent against B. catarrhalis and inhibited all the strains at a concentration of 0.05 micrograms/ml or less. No resistant strains were observed against cephems, new quinolones, erythromycin or MINO. 4. P. aeruginosa appeared to be rapidly developing resistance against new quinolones in patients with chronic P. aeruginosa respiratory infections who had been treated with these agents. In treating chronic respiratory infection due to P. aeruginosa, one must be watchful of rapid development of resistance by the organism or its replacement with S. pneumoniae.
Nishioka
K
K
First Department of Internal Medicine, School of Medicine, Tohoku University.
Ogiwara
H
H
Ida
S
S
Takishima
T
T
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D006193:Haemophilus influenzae / Q000187:drug effects*; D001936:Moraxella catarrhalis / Q000187:drug effects*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D012141:Respiratory Tract Infections / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D013997:Time Factors
D000900:Anti-Bacterial Agents