Arbekacin is a broad-spectrum
aminoglycoside licensed for systemic use in Japan and under clinical development as an inhalation
solution in the United States. We evaluated the occurrence of organisms isolated from
pneumonias in U.S. hospitalized patients (PHP), including
ventilator-associated pneumonia (VAP), and the in vitro activity of
arbekacin. Organism frequency was evaluated from a collection of 2,203 bacterial isolates (339 from VAP) consecutively collected from 25 medical centers in 2012 through the SENTRY Antimicrobial Surveillance Program.
Arbekacin activity was tested against 904 isolates from PHP collected in 2012 from 62 U.S. medical centers and 303 multidrug-resistant (MDR) organisms collected worldwide in 2009 and 2010 from various
infection types. Susceptibility to
arbekacin and comparator agents was evaluated by the reference broth microdilution method. The four most common organisms from PHP were Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella spp., and Enterobacter spp. The highest
arbekacin MIC among S. aureus isolates from PHP (43% methicillin-resistant S. aureus [MRSA]) was 4 μg/ml. Among P. aeruginosa isolates from PHP, only one had an
arbekacin MIC of >16 μg/ml (MIC50 and MIC90, 1 and 4 μg/ml), and susceptibility rates for
gentamicin,
tobramycin, and
amikacin were 88.0, 90.0, and 98.0%, respectively.
Arbekacin (MIC50, 2 μg/ml) and
tobramycin (MIC50, 4 μg/ml) were the most potent
aminoglycosides tested against Acinetobacter baumannii. Against Enterobacteriaceae from PHP,
arbekacin and
gentamicin (MIC50 and MIC90, 0.25 to 1 and 1 to 8 μg/ml for both compounds) were generally more potent than
tobramycin (MIC50 and MIC90, 0.25 to 2 and 1 to 32 μg/ml) and
amikacin (MIC50 and MIC90, 1 to 2 and 2 to 32 μg/ml).
Arbekacin also demonstrated potent in vitro activity against a worldwide collection of well-characterized MDR Gram-negative and MRSA strains.