Combined effects of panipenem and aminoglycosides on methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa in vitro.
BACKGROUND
Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa are the main causes of refractory infections that are often resistant to antimicrobial agents. In these cases, combination of agents with antimicrobial activity is being examined. However, few studies have investigated combined effects with antimicrobial agents including carbapenem and aminoglycosides.


METHODS
We evaluated the effects of panipenem (PAPM) combined with 3 aminoglycosides, arbekacin, amikacin, and netilmicin, and vancomicin (VCM) with an agar dilution checkerboard technique and the fractional inhibitory concentration index against 47 strains of MRSA and 56 strains of P. aeruginosa.


RESULTS
PAPM combined with VCM achieved a synergic effect against MRSA in 80.9%. PAPM combined with aminoglycosides showed only additive effects against MRSA and P. aeruginosa. When comparing the activity of Mueller-Hinton agar (MHA) medium with MHA medium diluted 40-fold (1/40 MHA) against P. aeruginosa, the mean minimum inhibitory concentration of PAPM was decreased to 1/16.


CONCLUSIONS
Combination of PAPM and VCM is effective against MRSA. Combinations of PAPM and aminoglycosides showed additive effects against MRSA and P. aeruginosa.
Katou
Ken
K
Department of Internal Medicine and Bioregulation, Nagoya City University, Graduate School of Medical Sciences, Aichi, Japan.
Nakamura
Atsushi
A
Kato
Takashi
T
Tonegawa
Ken
K
Kutsuna
Takeo
T
Niwa
Toshiaki
T
Morita
Hiroki
H
Itoh
Makoto
M
D000617:Aminoglycosides / Q000008:administration & dosage / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D006801:Humans; D066298:In Vitro Techniques; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D013211:Staphylococcus aureus / Q000187:drug effects*; D013845:Thienamycins / Q000008:administration & dosage / Q000494:pharmacology*
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D013845:Thienamycins; C039536:panipenem