THE INCIDENCE OF RESPIRATORY-TRACT PATHOGENS AND ANTIMICROBIAL SUSCEPTIBILITIES OF STREPTOCOCCUS-PNEUMONIAE, HAEMOPHILUS-INFLUENZAE AND MORAXELLA (BRANHAMELLA) CATARRHALIS ISOLATED BETWEEN 1990 AND 1993
K. Nishioka et al., THE INCIDENCE OF RESPIRATORY-TRACT PATHOGENS AND ANTIMICROBIAL SUSCEPTIBILITIES OF STREPTOCOCCUS-PNEUMONIAE, HAEMOPHILUS-INFLUENZAE AND MORAXELLA (BRANHAMELLA) CATARRHALIS ISOLATED BETWEEN 1990 AND 1993, Tohoku Journal of Experimental Medicine, 179(2), 1996, pp. 111-121
Using a quantitative culture of sputum, the incidence of pathogenic ba
cteria in respiratory infection in our laboratory between 1990 and 199
3 were investigated. While Haemophilus influenzae, Streptococcus pneum
oniae and Moraxella (Branhamella) catarrhalis mere isolated at high ra
tes (67 similar to 78%) from the specimens of outpatients throughout t
he study period, the incidence of S. pneumoniae has increased graduall
y. The antimicrobial susceptibilities of these three pathogens were ex
amined with the agar dilution method. A marked increase of penicillin
(PC) resistant S. pneumoniae (MIG greater than or equal to 0.1 mu g/ml
) was observed with a resistance rate of 2.1% in 1990 and 25% in 1993.
Resistance to erythromycin (EM, MIC greater than or equal to 1.56 mu
g/ml) was 8.5% in 1990 but then increased to 34% in 199'2. Most of the
PC resistant isolates were resistant to multidrugs such as EM, minocy
cline and clindamycin. The MICs of all beta-lactams examined for S. pn
eumoniae increased along with the MICs of PC, though the level varied
between drugs. The rates of beta-lactamase positive H. influenzae grad
ually decreased, being 14.3% in 1990 and 7.4% in 1993, whereas those o
f M. (B) catarrhalis were consistently high (>90%) every year. In addi
tion to beta-lactamase production, the emergence of strains of H. infl
uenzae and M.(B) catarrhalis resistant to new quinolone drugs should b
e noted.