Vol.58 No.1 January 2010
Annual changes in drug susceptibility of Pseudomonas aeruginosa isolated from blood and other clinical specimens
1)Faculty of Medicine, Toho University, 4-16-20 Omori-Nishi, Ota-ku, Tokyo, Japan
2)Infectious Disease Testing Department, Mitsubishi Chemical Medience Corporation
Abstract
We determined the susceptibility of Pseudomonas aeruginosa strains isolated from blood culture bottles of patients from 2007 to 2008 to different antibacterial agents. MIC50 of ciprofloxacin(CPFX) and meropenem against strains tested, i.e., 139 strains isolated from blood and 49 isolated from other clinical specimens, were 0.25-1 μg/mL. The frequency of strains nonsusceptible to amikacin(AMK) and colistin(CL) was 2.9-6.1% among the test antibacterial agents tested. The frequency of strains nonsusceptible to other antibacterial agents was 15.8-51.4%, except that the frequency of strains nonsusceptible to gentamicin isolated from blood was 8.6%. MICs of CL and polymyxin B(PL-B) for all strains nonsusceptible to CL and PL-B were judged to be intermediate but not to be resistant based on CLSI guidelines.
Changes in the frequency of P. aeruginosa strains nonsusceptible to different antibacterial agents from 2005 to 2008 were as follows: The frequency of strains nonsusceptible to imipenem isolated from blood was 34.1% in 2005, but decreased to 19.4% in 2008. The frequency of strains nonsusceptible to cefepime(CFPM) increased from 16.5 to 26.9%. The frequency of strains nonsusceptible to CPFX isolated from other clinical specimens also increased. Multiple drug-resistant strains and metallo-β-lactamase-producing strains were continuously detected.
The frequency of P. aeruginosa strains nonsusceptible to carbapenems has decreased since 2005. The frequency of strains nonsusceptible to CFPM and CPFX, in contrast, is still high and multiple drug-resistant strains are also continuously detected, indicating the importance of continuing to monitor the susceptibility of P. aeruginosa strains.
Key word
blood culture, multidrug-resistant Pseudomonas aeruginosa, metallo β-lactamase
Received
September 8, 2009
Accepted
November 9, 2009
Jpn. J. Chemother. 58 (1): 7-13, 2010
