BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and some gram-negative bacilli are very prevalent nosocomial pathogens, commonly causing mixed infections, and are often resistant to multiple drugs. Arbekacin is an aminoglycoside used for the treatment of MRSA infections, but is also active against some gram-negative bacilli. The aim of this study was to determine in vitro activity of arbekacin against recent clinical isolates of staphylococci and gram-negative bacilli. Materials and METHODS: The strains were isolated from clinical specimens of patients at Severance Hospital in 2003. Antimicrobial susceptibility was tested by the Clinical and Laboratory Standards Institute agar dilution method. The following arbekacin breakpoints were used: susceptible, < or =4 microgram/mL; and resistant, > or =16 microgram/mL . RESULTS: All isolates of staphylococci tested were inhibited by < or =4 microgram/mL of arbekacin, regardless of their methicillin susceptibility. The MIC90s of arbekacin, 1-4 microgram/mL, were 8->32-fold and >32-128-fold lower than those of amikacin and gentamicin, respectively. The resistance rates of MRSA, methicillin-susceptible S. aureus, methicillin-resistant coagulase-negative staphylococci (CNS) and methicillin-susceptible CNS were 0% to arbekacin, 0-54% to amikacin, and 24-79% to gentamicin. The MIC90s of arbekacin for Escherichia coli and Citrobacter freundii, 1 microgram/mL and 16 microgram/mL, were 2-4-fold and 8-16-fold lower than those of amikacin and gentamicin, respectively. However, The MIC90s of arbekacin for other species of gram-negative bacilli, 64->128 microgram/mL, were similar to those of other aminoglycosides. CONCLUSIONS: Arbekacin may be a useful alternative to glycopeptides for the treatment of monomicrobial methicillin-resistant staphylococcal infections, as well as mixed infections with gram-negative bacilli, as most isolates of E. coli, C. freundii and some other gram-negative bacilli were also susceptible to arbekacin.
Anti-Bacterial Agents/*pharmacology ; Dibekacin/*analogs & derivatives/pharmacology ; Gram-Negative Bacteria/*drug effects/isolation & purification ; Gram-Negative Bacterial Infections/microbiology ; Humans ; Methicillin Resistance ; Microbial Sensitivity Tests ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/isolation & purification

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and some gram-negative bacilli are very prevalent nosocomial pathogens, commonly causing mixed infections, and are often resistant to multiple drugs. Arbekacin is an aminoglycoside used for the treatment of MRSA infections, but is also active against some gram-negative bacilli. The aim of this study was to determine in vitro activity of arbekacin against recent clinical isolates of staphylococci and gram-negative bacilli. Materials and METHODS: The strains were isolated from clinical specimens of patients at Severance Hospital in 2003. Antimicrobial susceptibility was tested by the Clinical and Laboratory Standards Institute agar dilution method. The following arbekacin breakpoints were used: susceptible, < or =4 microgram/mL; and resistant, > or =16 microgram/mL . RESULTS: All isolates of staphylococci tested were inhibited by < or =4 microgram/mL of arbekacin, regardless of their methicillin susceptibility. The MIC90s of arbekacin, 1-4 microgram/mL, were 8->32-fold and >32-128-fold lower than those of amikacin and gentamicin, respectively. The resistance rates of MRSA, methicillin-susceptible S. aureus, methicillin-resistant coagulase-negative staphylococci (CNS) and methicillin-susceptible CNS were 0% to arbekacin, 0-54% to amikacin, and 24-79% to gentamicin. The MIC90s of arbekacin for Escherichia coli and Citrobacter freundii, 1 microgram/mL and 16 microgram/mL, were 2-4-fold and 8-16-fold lower than those of amikacin and gentamicin, respectively. However, The MIC90s of arbekacin for other species of gram-negative bacilli, 64->128 microgram/mL, were similar to those of other aminoglycosides. CONCLUSIONS: Arbekacin may be a useful alternative to glycopeptides for the treatment of monomicrobial methicillin-resistant staphylococcal infections, as well as mixed infections with gram-negative bacilli, as most isolates of E. coli, C. freundii and some other gram-negative bacilli were also susceptible to arbekacin.
Anti-Bacterial Agents/*pharmacology ; Dibekacin/*analogs & derivatives/pharmacology ; Gram-Negative Bacteria/*drug effects/isolation & purification ; Gram-Negative Bacterial Infections/microbiology ; Humans ; Methicillin Resistance ; Microbial Sensitivity Tests ; Staphylococcal Infections/microbiology ; Staphylococcus aureus/*drug effects/isolation & purification

This study was undertaken to evaluate the in vitro activities of arbekacin-based combination regimens against vancomycin hetero-intermediate Staphylococcus aureus (hetero-VISA). Combinations of arbekacin with vancomycin, rifampin, ampicillin-sulbactam, teicoplanin, or quinipristin-dalfopristin against seven hetero-VISA strains and two methicillin-resistant S. aureus strains were evaluated by the time-kill assay. The combinations of arbekacin with vancomycin, teicoplanin, or ampicillinsulbactam showed the synergistic interaction against hetero-VISA strains. Data suggest that these arbekacin-based combination regimens may be useful candidates for treatment options of hetero-VISA infections.
Virginiamycin/administration & dosage ; Vancomycin/*administration & dosage ; Teicoplanin/administration & dosage ; Sulbactam/administration & dosage ; Staphylococcus aureus/*drug effects/isolation & purification ; Staphylococcal Infections/drug therapy/microbiology ; Microbial Sensitivity Tests ; Methicillin Resistance ; Humans ; Drug Synergism ; Drug Resistance, Bacterial ; Dibekacin/administration & dosage/*analogs & derivatives ; Anti-Bacterial Agents/*administration & dosage ; Ampicillin/administration & dosage ; Aminoglycosides/*administration & dosage

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of ear infections. We attempted to evaluate the clinical usefulness of arbekacin in treating chronic suppurative otitis media (CSOM) by comparing its clinical efficacy and toxicity with those of vancomycin. Efficacy was classified according to bacterial elimination or bacteriologic failure and improved or failed clinical efficacy response. Ninety-five subjects were diagnosed with CSOM caused by MRSA. Twenty of these subjects were treated with arbekacin, and 36 with vancomycin. The bacteriological efficacy (bacterial elimination, arbekacin vs. vancomycin: 85.0% vs. 97.2%) and improved clinical efficacy (arbekacin vs. vancomycin; 90.0% vs. 97.2%) were not different between the two groups. However, the rate of complications was higher in the vancomycin group (33.3%) than in the arbekacin group (5.0%) (P=0.020). In addition, a total of 12 adverse reactions were observed in the vancomycin group; two for hepatotoxicity, one for nephrotoxicity, eight for leukopenia, two for skin rash, and one for drug fever. It is suggested that arbekacin be a good alternative drug to vancomycin in treatment of CSOM caused by MRSA.
Adult ; Aged ; Anti-Bacterial Agents/administration & dosage ; Chronic Disease ; Dibekacin/administration & dosage/*analogs & derivatives ; Female ; Humans ; Male ; Methicillin-Resistant Staphylococcus aureus/*drug effects ; Middle Aged ; Otitis Media, Suppurative/diagnosis/*drug therapy/microbiology ; Staphylococcal Infections/diagnosis/*drug therapy/microbiology ; Treatment Outcome ; Vancomycin/*administration & dosage ; Young Adult