Vol.56 No.5 September 2008

Antimicrobial susceptibility of clinical isolates of aerobic Gram-negative bacteria in 2004

Isamu Yoshida¹⁾, Takaji Fujimura¹⁾, Yoshihisa Itoh²⁾, Mineji Tachibana³⁾, Mitsuo Kaku⁴⁾, Keiji Kanemitsu⁵⁾, Choichiro Takahashi⁶⁾, Joji Shiotani⁷⁾, Yuka Ono⁸⁾, Hisashi Baba⁹⁾, Shuji Matsuo¹⁰⁾, Seishi Asari¹¹⁾, Kimiko Matsuoka¹²⁾, Nobuchika Kusano¹³⁾, Motoko Nose¹³⁾, Tetsunori Saikawa¹⁴⁾, Kazufumi Hiramatsu¹⁴⁾, Shigeru Kohno¹⁵⁾, Yoichi Hirakata⁴⁾, Nobuhisa Yamane¹⁶⁾, Isamu Nakasone¹⁷⁾ and Yoshinori Yamano¹⁾

¹⁾Discovery Research Laboratories, Shionogi & Co., Ltd., 3-1-1 Futaba-cho, Toyonaka, Osaka, Japan
²⁾Asahikawa Medical College
³⁾Asahikawa Medical College Hospital
⁴⁾Tohoku University Graduate School of Medicine
⁵⁾Fukushima Medical University Hospital
⁶⁾Yamagata University Hospital
⁷⁾Cancer Institute Hospital
⁸⁾Mitsui Memorial Hospital
⁹⁾Nagoya University Hospital
¹⁰⁾Tenri Hospital
¹¹⁾Osaka University Hospital
¹²⁾Osaka General Medical Center
¹³⁾Okayama University Hospital
¹⁴⁾Oita University Hospital
¹⁵⁾Nagasaki University Hospital of Medicine and Dentistry
¹⁶⁾Faculty of Medicine, University of the Ryukyus
¹⁷⁾University Hospital of the Ryukyus

Abstract

We determined MICs of antibacterial agents against 1,248 clinical strains of aerobic Gram-negative bacteria (19 genus or species) isolated at 16 Japanese facilities in 2004. MICs were determined using mostly broth microdilution method and antibacterial activity was assessed. Antibacterial susceptibility of Enterobacteriaceae to most β-lactams was comparable to that described in our previous report on isolates in 2002. Strains producing extended-spectrum β-lactamases(ESBL) accounted for 2.5% of Escherichia coli, 0% of Klebsiella spp., and 9.2% of Proteus spp. Notably, 16.7% of Proteus mirabilis was found to produce ESBL. Most antibacterial agents showed good activity against Moraxella catarrhalis. Among Haemophilus influenzae, 9.3% produced β-lactamase and 57.7% were β-lactamase-negative ampicillin-resistant strains when classified by penicillin-binding protein 3 mutation. Although few antibacterial agents against Pseudomonas aeruginosa have potent activity, only three agents-tobramycin, doripenem, and amikacin-showed an MIC₉₀ of ≤8 μg/mL. Of all P. aeruginosa strains, 8.9% were resistant to seven or more agents of ten antipseudomonal agents, a decrease compared to results reported in 2002. Against other glucose-non-fermentative Gram-negative bacteria, the activity of most antibacterial agents was similar to that in 2002.

Key word

clinical isolate, surveillance, Gram-negative bacteria, multidrug-resistant Pseudomonas aeruginosa, drug susceptibility

Received

January 31, 2008

Accepted

June 17, 2008

Jpn. J. Chemother. 56 (5): 562-579, 2008