Antimicrobial susceptibility of Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa isolated in major hospitals in Nagano prefecture

摘要

We determined the minimum inhibitory concentration (MIC) of various antimicrobial agents against 140 strains of Streptococcus pneumoniae, 131 strains of Haemophilus influenzae and 178 strains of Pseudomonas aeruginosa isolated from respiratory organs in 28 affiliated hospitals in Nagano prefecture between December 2002 and February 2003. The results of this report were as followed: 1. All 140 strains of S. pneumoniae were classified into 3 groups; penicillin-susceptible S. pneumoniae (PSSP) (47.1%), penicillin-intermediate S. pneumoniae (PISP) (43.6%) and penicillin-resistant S. pneumoniae (PRSP) (9.3%). 2. Carbapenems and glycopeptide (vancomycin) had highly potent antimicrobial activity against PISP and PRSP like PSSP. However, some of PISP or PRSP isolates were resistant to cephalosporins and a fluoroquinolone (levofloxacin). 3. All 131 strains ofH. Influenzae were also classified into three groups; ampicillin sensitive H. influenzae (73.3%), beta-lactamase producing ampicillin resistant H. influenzae (BLPAR) (8.4%) and beta-lactamase negative ampicillin resistant H. influenzae (BLNAR) (18.3%). 4. Carbapenems and a fluoroquinolone had highly potent antimicrobial activity against BLPAR and BLNAR. However, there were clear differences among 4 carbapenems for the antimicrobial activity. Ceftriaxone (CTRX) was the most active among cepharosporins in this study. 5. The rate of P. aeruginosa isolates resistant to carbapenems, a fluoroquinolone and aminoglycosides were about 11 to approximately 16%, 15% and 0.6 to approximately 8%, respectively. None of the strains was resistant to all 3 antimicrobial classes, but 3 strains were resistant to combination of 2 classes. 6. The MIC50 and MIC90 values of various antibiotics against S. pneumoniae, H. influenzae and P. aeruginosa were different in all 4 regions. In conclusion, the antimicrobial surveillance programs are important for guiding empiric therapy and for focusing interventional control of antimicrobial resistance in regions and hospitals.