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

Keizo Yamaguchi, Nobuhiko Furuya, Morihiro Iwata, Naoki Watanabe, Nobuyuki Uehara, Minoru Yasujima, Takeshi Kasai, Mitsuo Kaku, Yuko Abe, Jun Igari, Toyoko Oguri, Hisashi Baba, Hitoshi Yoshimura, Kiyoharu Yamanaka, Satoshi Ischiyama, Nobuchika Kusano, Naoko Murao, Junko Ono, Hiromi Tou, Kaoru OkadaMasami Ishida, Yoichi Hirakata, Junichi Matsuda

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


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 MIG50 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-0.5,4 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.

Original languageEnglish
Pages (from-to)627-640
Number of pages14
JournalJapanese Journal of Chemotherapy
Issue number10
Publication statusPublished - Oct 2005
Externally publishedYes


  • Fluoroquinolone
  • Gatifloxacin
  • Surveillance

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)


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