Vol.56 No.5 September 2008

Antimicrobial susceptibility of clinical isolates of aerobic Gram-positive cocci and anaerobic bacteria in 2004

Takaji Fujimura¹⁾, Isamu Yoshida¹⁾, 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

The activity of antibacterial agents against aerobic Gram-positive cocci (28 species, 1,020 strains) and anaerobic bacteria (21 species, 170 strains) isolated from clinical specimens in 2004 at 16 clinical facilities in Japan were studied using either broth microdilution or agar dilution method. The ratio of methicillin-resistant strains among Staphylococcus aureus was 63.1% and Staphylococcus epidermidis 84.2%, suggesting that resistant strains were isolated at high frequency. Vancomycin(VCM), linezolid(LZD), and quinupristin/dalfopristin (QPR/DPR) had good antibacterial activity against methicillin-resistant S. aureus and methicillin-resistant S. epidermidis, with MIC₉₀s of ≤2 μg/mL. The ratio of penicillin(PC) intermediate and resistant strains classified by mutations of PC-binding proteins among Streptococcus pneumoniae was 86.5%. Cefpirome, ceftriaxone, carbapenem antibiotics, VCM, and teicoplanin had MIC₉₀s of ≤1 μg/mL against PC-intermediate and resistant S. pneumoniae strains. VCM and teicoplanin also showed good antibacterial activity against Enterococcus faecalis and Enterococcus faecium with MIC₉₀s of ≤2 μg/mL, and no resistant strains were detected. Of E. faecium strains, 7.8% showed intermediate and 23.4% resistant to LZD or QPR/DPR. Among anaerobes, carbapenems showed good activity against Peptococcaceae, Bacteroides spp., and Prevotella spp. The susceptibility of Bacteroides spp. other than Bacteroides fragilis to these antibiotics, however, appeared to be lowered, necessitating well-focused surveillance studies.

Key word

clinical isolate, surveillance, Gram-positive cocci, anaerobe, drug susceptibility

Received

January 31, 2008

Accepted

June 17, 2008

Jpn. J. Chemother. 56 (5): 543-561, 2008