Epidemiology and drug susceptibility of Pseudomonas aeruginosa strains isolated in the Chugoku region of Japan. Infection Forum in the Chugoku Region

Recently, there have been reports concerning an increased frequency of isolation of multi-drug resistant Pseudomonas aeruginosa (MDRP) strains in hospitals and other clinical settings as well as the associated risk of their hospital-acquired infections; in such a situation, it has been a major challenge to establish methods of managing and treating the infections. In order to investigate the trend of P. aeruginosa, the Infection Forum in the Chugoku Region has conducted to a multi-center collaborative study to isolate P. aeruginosa strains from sputum and urine samples collected between October 2006 and September 2008, analyzed the drug susceptibility and the pulsed-field gel electrophoresis (PFGE) patterns of each strain, and assessed epidemiologic characteristics. Of the 738 P. aeruginosa strains collected in this study, 152 (20.6%), 179 (24.3%), 47 (6.4%), and 39 (5.3%) were found to be ciprofloxacin-resistant, imipenem-resistant, amikacin-resistant, and MDRP, respectively. Among the various antimicrobial agents tested, arbekacin (ABK) revealed the strongest inhibitory effects on each drug-resistant and MDRP strain; therefore, ABK was considered as a potential candidate for future treatment of diseases caused by P. aeruginosa. The study also showed that the detection rates of MDRP varied a lot from hospital to hospital. In addition, PFGE-based cluster analyses revealed several strains isolated in the same hospital exhibited a similar PFGE pattern and the same drug susceptibility, suggesting the presence of "unique" hospital-specific strains.