In Vitro Effects of Combined Antibiotics against Multidrug-resistant Pseudomonas aeruginosa.
- Author:
Hyun Joo PAI
1
Author Information
1. Infectious Diseases, Hanyang University College of Medicine, Seoul, Korea. paihj@hanyang.ac.kr
- Publication Type:In Vitro ; Original Article
- Keywords:
Multidrug-resistant P. aeruginosa;
Checkerboard;
In vitro killing assay
- MeSH:
Amikacin;
Anti-Bacterial Agents;
Aztreonam;
Ceftazidime;
Cephalosporins;
Ciprofloxacin;
Homicide;
Microbial Sensitivity Tests;
Pseudomonas;
Pseudomonas aeruginosa;
Thienamycins
- From:Korean Journal of Medicine
2010;79(1):41-47
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND/AIMS: The inhibitory effects of the combination of beta-lactam with ciprofloxacin or amikacin against clinical isolates of multidrug-resistant Pseudomonas aeruginosa were evaluated. METHODS: This study examined ten isolates with variable levels of resistance to ceftazidime, cefepime, piperacillin/tazobactam, meropenem, ciprofloxacin, and amikacin. The efficacy of the combined antibiotics was studied using a checkerboard method or in vitro killing assay. RESULTS: The combination of ceftazidime, cefepime, aztreonam, piperacillin-tazobactam, or meropenem with amikacin showed synergistic effects for all of the strains regardless of the minimum inhibitory concentration (MIC) of amikacin, but combination with ciprofloxacin showed a synergistic effect for the isolate with a low MIC of ciprofloxacin by the checkerboard method. The isolates with a high MIC of ciprofloxacin showed an indifferent effect in combination with beta-lactam and ciprofloxacin. The in vitro killing assay showed that meropenem with ciprofloxacin acted synergistically for the isolates with a MIC of 16 microgram/mL of ciprofloxacin. However, amikacin showed synergistic effects with meropenem for the isolates with high-level resistance against amikacin, i.e., up to an MIC of 128 microgram/mL. Contrary to the checkerboard method results, no synergy was observed for the combination of ceftazidime/piperacillin-tazobactam and amikacin. CONCLUSIONS: Meropenem with amikacin can be the first choice for infections caused by multidrug-resistant P. aeruginosa when the level of resistance is not known.
