[Isolation-frequency and antibiotic susceptibility of Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa isolated in regional core hospitals in the Nagaoka district of Niigata Prefecture (changes for 3 years)].

We measured MICs of various antimicrobial agents against Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa isolated in the Nagaoka district of Niigata Prefecture in 2000 (March-May), 2001 (January-May), and 2002 (March-May). S. pneumoniae: Fifty-six strains were isolated in 2000, 119 strains in 2001, and 88 strains in 2002. In 2000, 2001, and 2002, 24 strains (42.9%), 58 strains (48.7%), and 40 strains (45.5%), respectively, were penicillin-intermediate S. pneumoniae (PISP), and 4 strains (7.1%), 12 strains (10.1%), and 7 strains (8.0%), respectively, were penicillin-resistant S. pneumoniae (PRSP). Carbapenems had the most excellent antimicrobial activity, followed by penicillin G, against penicillin-susceptible S. pneumoniae (PSSP), PISP, and PRSP. H. influenzae: Seventy-six strains were isolated in 2000, 154 strains in 2001, and 91 strains in 2002. In 2000, 2001, and 2002, 6 strains (7.9%), 8 strains (5.2%), and 7 strains (7.7%), respectively, were beta-lactamase-producing ampicillin (ABPC)-resistant strains (MIC > or = 2 micrograms/ml), showing no increase, and 14 strains (18.4%), 70 strains (45.5%), and 31 strains (34.1%), respectively, were beta-lactamase-non-producing ABPC-resistant strains (MIC > or = 2 micrograms/ml), showing a slight increase. Ceftriaxon, meropenem (MEPM), and levofloxacin had excellent antimicrobial activity against these resistant strains. P. aeruginosa: In 2000, 2001, and 2002, 135, 74, and 91 strains, respectively, were isolated, and 14 strains (10.4%), 17 strains (23.0%), and 24 strains (26.4%), respectively, were imipenem-resistant (MIC > or = 16 micrograms/ml), showing a slight increase. MEPM, biapenem, and ciprofloxacin had excellent antimicrobial activity against P. aeruginosa.