Vol.53 No.10 October 2005

Surveillance of susceptibility of clinical isolates to gatifloxacin and various antimicrobial agents

Keizo Yamaguchi¹⁾, Nobuhiko Furuya¹⁾, Morihiro Iwata²⁾, Naoki Watanabe^3,4), Nobuyuki Uehara⁴⁾, Minoru Yasujima⁵⁾, Takeshi Kasai⁶⁾, Mitsuo Kaku⁷⁾, Yuko Abe⁸⁾, Jun Igari⁹⁾, Toyoko Oguri¹⁰⁾, Hisashi Baba¹¹⁾, Hitoshi Yoshimura¹²⁾, Kiyoharu Yamanaka¹³⁾, Satoshi Ichiyama¹⁴⁾, Nobuchika Kusano¹⁵⁾, Naoko Murao¹⁵⁾, Junko Ono¹⁶⁾, Hiromi Tou¹⁶⁾, Kaoru Okada¹⁷⁾, Masami Ishida¹⁸⁾, Yoichi Hirakata¹⁹⁾ and Junichi Matsuda¹⁹⁾

¹⁾Department of Microbiology and Infectious Diseases, Toho University School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo, Japan
²⁾Department of Laboratory Medicine, Toho University Omori Medical Center
³⁾Department of Clinical Laboratory Medicine, Sapporo Medical University School of Medicine
⁴⁾Division of Laboratory Diagnosis, Sapporo Medical University Hospital
⁵⁾Department of Laboratory Medicine, Hirosaki University School of Medicine
⁶⁾Department of Clinical Laboratory, Hirosaki University Hospital
⁷⁾Department of Infection Control and Laboratory Diagnostics, Tohoku University Graduate School of Medicine
⁸⁾Department of Clinical Laboratory, Tohoku University Hospital
⁹⁾Department of Clinical Pathology, Juntendo University School of Medicine
¹⁰⁾Department of Clinical Laboratory, Juntendo University Hospital
¹¹⁾Department of Infectious Diseases, Nagoya University Hospital
¹²⁾Internal Medicine, Mie Prefectural Shima Hospital
¹³⁾Division of Clinical Laboratory, Otemae Hospital
¹⁴⁾Department of Clinical Laboratory Medicine, Kyoto University Graduate School of Medicine
¹⁵⁾Department of Central Clinical Laboratory, Okayama University Hospital
¹⁶⁾Central Clinical Laboratory, Fukuoka University Hospital
¹⁷⁾Internal Medicine, Kitakyushu Municipal Medical Center
¹⁸⁾Microbiology Laboratory, Kitakyushu Municipal Medical Center
¹⁹⁾Department of Laboratory Medicine, Nagasaki University Hospital of Medicine and Dentistry

Abstract

In order to continually examine the susceptibility of clinical isolates against gatifloxacin (GFLX), we conducted a surveillance measuring that of 2,508 strains of four gram-positive and seven gram-negative pathogens to 12 antimicrobials including GFLX, during the period from November 2004 to March 2005 following previous surveillance conducted in 2002. Tested pathogens were isolated from sputum, urine and sinus discharge obtained from 15 facilities throughout Japan. GFLX exhibited superior antibacterial activity against Streptococcus pneumoniae, comparison to other fluoroquinolones, by showing same MIC₅₀ and MIC₉₀ values of 0.25 μg/mL and a satisfactory susceptible rate at 96.5%. Antibacterial activity of GFLX was not influenced by the development of penicillin-resistance in S. pneumoniae. The MIC₉₀ values of fluoroquinolones against Haemophilus influenzae and Moraxella catarrhalis were commonly as low as 0.015 μg/mL to 0.03 μg/mL. The MIC₅₀ and MIC₉₀ values of GFLX against Escherichia coli and Enterococcus faecalis were 0.06 μg/mL-0.5 μg/mL and 8 μg/mL-16 μg/mL, respectively. The susceptible rate for fluoroquinolones were 83-67%. On an average, this surveillance indicated that fluoroquinolones kept strong antibacterial activities against H. influenzae and M. catarrhalis. Among others, GFLX has maintained strong antibacterial activity against S. pneumoniae as the MIC₉₀ value of 0.25 μg/mL was identical to that observed at the launch. It was thought that GFLX was the clinically useful drugs for empiric therapy against main pathogens of respiratory tract, otorhinolaryngology and urinary tract infections. While antibacterial activities of fluoroquinolones against E. coli and E. faecalis did not almost change from 2002 surveillance, it was thought the susceptibility needed to be examined continually in future.

Key word

fluoroquinolone, gatifloxacin, surveillance

Received

August 19, 2005

Accepted

September 26, 2005

Jpn. J. Chemother. 53 (10): 627-640, 2005