Analysis of the influence of drug resistance factors on the efficacy of combinations of antibiotics for multidrug-resistant Pseudomonas aeruginosa isolated from hospitals located in the suburbs of Kanto area, Japan

作者：Kataoka Hiroshi; Ida Takashi; Ishii Yoshikazu^*; Tateda Kazuhiro; Oguri Toyoko; Yoshida Atsushi; Okuzumi Katsuko; Oishi Tsuyoshi; Tsukahara Miyuki; Mori Shin ichiro; Yoneyama Akiko; Araoka Hideki; Mitsuda Toshihiro; Sumitomo Midori; Moriya Kyoji; Goto Mieko; Nakamori Yoshitaka; Shibayama Akiyoshi; Ohmagari Norio; Sato Tomoaki; Yamaguchi Keizo

来源：Journal of Global Antimicrobial Resistance, 2013, 1(2): 91-96.

DOI：10.1016/j.jgar.2013.03.005

• Multidrug-resistant Pseudomonas aeruginosa
• Combination effect
• Resistance factor

Infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa are very difficult to treat. The aim of this study was to develop more effective treatments by investigating in vitro the effects of combinations of antibiotics against 47 MDR Pseudomonas aeruginosa isolates harbouring various resistance factors. The isolates included 41 (87%) metallo-beta-lactamase (MBL)-positive strains, 37 (79%) strains with mutations in OprD and 46 (98%) strains carrying the genes encoding aminoglycoside-modifying enzymes (AMEs). The quinolone resistance-determining region was mutated in all of the strains. These strains were classified into 16 groups according to amplified fragment length polymorphism and resistance factors. The effects of combinations of antibiotics on 16 representative strains were determined using a %26apos;Break-point Checkerboard Plate%26apos; assay. Combinations of amikacin + aztreonam (coverage rate, 81.3%) and arbekacin + aztreonam (93.8%) inhibited growth. In contrast, combinations of ciprofloxacin + meropenem (6.3%) and ciprofloxacin + ceftazidime (12.5%) were much less effective. Aztreonam and arbekacin (or amikacin) are not substrates for MBLs and AMEs, respectively. We conclude that the combined effects of these drugs were possibly because of resistance factors.

• 出版日期2013-6