title: Relation between the antimicrobial susceptibility of clinical isolates of Pseudomonas aeruginosa from respiratory specimens and antimicrobial use density (AUD) from 2005 through 2008.
abstract: OBJECTIVE
  To examine the relation between annual trends in the antimicrobial susceptibility of Pseudomonas aeruginosa and drug usage, we compared annual changes in the susceptibility rates of P. aeruginosa clinical isolates during a 4-year period and annual trends in the overall usage of antimicrobials during the same period.
  
  
  METHODS
  We studied annual trends in MIC(90)/MIC(50), antimicrobial use density (AUD), and antimicrobial susceptibility rates based on clinical breakpoints for 150 strains of P. aeruginosa isolated from respiratory specimens at Dokkyo Medical University Hospital from 2005 through 2008.
  
  
  RESULTS
  The MIC(90)/MIC(50) of antimicrobials effective against P. aeruginosa in years 2005, 2006, 2007, and 2008 were as follows: imipenem, 32/2, 32/1, 8/2, and 16/1 microg/mL; meropenem, 8/1, 8/1, 4/0.5, and 4/0.5 microg/mL; and biapenem, 16/1, 32/0.5, 4/0.5, and 8/0.5 microg/mL, indicating that susceptibility to carbapenems increased slightly. The MIC(90)/MIC(50) was 4/0.25, 2/0.125, 1/0.125, and 2/0.25 microg/mL for ciprofloxacin, 8/4, 8/4, 4/4, and 8/4 microg/mL for amikacin, 64/16, 64/16, 64/16, and 64/16 microg/mL for sulbactam/cefoperazone, 8/2, 16/2, 32/2, and 8/2 microg/mL for ceftazidime, indicating little change. The AUDs of fourth-generation cephalosporins increased from 2005 to 2008 (16.2, 18.4, 28.0, and 23.0), while the AUDs of carbapenems decreased (25.7, 23.7, 10.9, and 12.5).
  
  
  CONCLUSIONS
  The decrease in the AUDs of carbapenems was associated with increased susceptibility rates of P. aeruginosa to carbapenem derivatives. A continuous understanding of trends in the resistance of P. aeruginosa and various other pathogens is essential for designing countermeasures against nosocomial infections, including the proper and effective use of antimicrobials.
authors.affiliation: Department of Pulmonary Medicine and Clinical Immunology, Dokkyo University School of Medicine, Japan. y-fuku@dokkyomed.ac.jp
authors.forename: Yasutsugu
authors.initials: Y
authors.lastname: Fukushima
authors.forename: Fumiya
authors.initials: F
authors.lastname: Fukushima
authors.forename: Kuniyoshi
authors.initials: K
authors.lastname: Kamiya
authors.forename: Yumeko
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Tatewaki
authors.forename: Issei
authors.initials: I
authors.lastname: Yamada
authors.forename: Hirokuni
authors.initials: H
authors.lastname: Hirata
authors.forename: Kumiya
authors.initials: K
authors.lastname: Sugiyama
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Ishii
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fukuda
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D004352:Drug Resistance, Microbial; D024901:Drug Resistance, Multiple, Bacterial; D006785:Hospitals, University / Q000639:trends; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000639:trends; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification*
chemical_list: D000900:Anti-Bacterial Agents