In Vitro Activities of Isepamicin and Other Aminoglycosides against Gram-Negative Organisms / 감염과화학요법

ABSTRACT

BACKGROUND: The increasing incidence of multidrug-resistant gram-negative bacteria causing nosocomial infections is an important clinical problem. Isepamicin is a recently developed aminoglycoside which has been known to have potent activity against gram-negative organisms. We evaluated the in vitro activities of isepamicin and other aminoglycosides against a large number of gram-negative organisms. MATERIALS AND METHODS: We tested the in vitro antimicrobial activities of isepamicin, amikacin, gentamicin, and tobramycin against 566 gram-negative organisms collected between January 2006 and June 2006 in Asan Medical Center. Minimal inhibitory concentrations (MICs) were determined and interpreted according to the recommendations of Clinical and Laboratory Standard Institute (CLSI). The breakpoint MIC used for interpretation of isepamicin was MIC or =64 microgram/mL as resistant. RESULTS: The MIC50/MIC90 of isepamicin for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacter cloacae were 1/2, 0.5/>128, 4/16, 16/>128, and 1/2 microgram/mL, respectively. The susceptibilities for E. coli, K. pneumoniae, P. aeruginosa, A. baumannii, and E. cloacae were 100%, 86.4%, 89.7%, 50.0%, and 96.6%, respectively. For E. coli, K. pneumoniae, P. aeruginosa, and E. cloacae, isepamicin had better in vitro activities than gentamicin and tobromycin, and had similar activities with amikacin. For A. baumanii, all four tested aminoglycosides had similar in vitro activities. CONCLUSION: Isepamicin had excellent in vitro activities against gram-negative organisms, except A. baumanii. The overall in vitro activities were similar with amikacin.