title: Comparative in vitro activities of nemonoxacin, doripenem, tigecycline and 16 other antimicrobials against Nocardia brasiliensis, Nocardia asteroides and unusual Nocardia species.
abstract: OBJECTIVE
  The aim of this study was to assess the in vitro activities of nemonoxacin (a novel non-fluorinated quinolone), doripenem, tigecycline and 16 other antimicrobial agents against the Nocardia species.
  
  
  METHODS
  MICs of 19 antimicrobial agents for 125 clinical isolates of the Nocardia species were determined by the broth microdilution method.
  
  
  RESULTS
  Nocardia brasiliensis (n = 61), Nocardia asteroides (n = 45), Nocardia flavorosea (n = 5), Nocardia otitidiscaviarum (n = 4), Nocardia farcinica (n = 3), Nocardia beijingensis (n = 2), Nocardia puris (n = 2) and one each of Nocardia nova, Nocardia jinanensis and Nocardia takedensis were identified based on a 16S rRNA gene sequencing analysis. For N. brasiliensis isolates, the MIC(90)s of the tested quinolones were in the order nemonoxacin < gemifloxacin = moxifloxacin < levofloxacin = ciprofloxacin, and the MIC(90)s of the tested carbapenems were in the order doripenem = meropenem < ertapenem < imipenem. Tigecycline had a lower MIC(90) (1 mg/L) than linezolid (8 mg/L). For N. asteroides isolates, the MIC(90)s of the tested quinolones were in the order nemonoxacin < gemifloxacin = moxifloxacin < levofloxacin < ciprofloxacin, and the MIC(90)s of the tested carbapenems were in the order doripenem = meropenem = imipenem < ertapenem. For the other 19 Nocardia species isolates, nemonoxacin showed good activity with the lowest MIC(90) of the tested quinolones. Among the four tested carbapenems, doripenem and meropenem had comparatively lower MIC(90)s.
  
  
  CONCLUSIONS
  The results of this in vitro study suggest that nemonoxacin, linezolid and tigecycline show promise as treatment options for nocardiosis. Further investigation of their clinical role is warranted.
authors.affiliation: Department of Internal Medicine, Yi-Min Hospital, Taipei, Taiwan.
authors.forename: Chih-Cheng
authors.initials: CC
authors.lastname: Lai
authors.forename: Che-Kim
authors.initials: CK
authors.lastname: Tan
authors.forename: Sheng Hsiang
authors.initials: SH
authors.lastname: Lin
authors.forename: Chun-Hsing
authors.initials: CH
authors.lastname: Liao
authors.forename: Chien-Hong
authors.initials: CH
authors.lastname: Chou
authors.forename: Hsiao-Leng
authors.initials: HL
authors.lastname: Hsu
authors.forename: Yu-Tsung
authors.initials: YT
authors.lastname: Huang
authors.forename: Po-Ren
authors.initials: PR
authors.lastname: Hsueh
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D006801:Humans; D008826:Microbial Sensitivity Tests; D009615:Nocardia / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D009617:Nocardia Infections / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S