title: Fluoroquinolone resistance during 2000-2005: an observational study.
abstract: BACKGROUND
  Moxifloxacin is a respiratory fluoroquinolone with a community acquired pneumonia indication. Unlike other fluoroquinolones used in our healthcare system, moxifloxacin's urinary excretion is low and thus we hypothesized that increased use of moxifloxacin is associated with an increase in fluoroquinolone resistance amongst gram negative uropathogens.
  
  
  METHODS
  All antibiograms for Gram negative bacteria were obtained for 2000 to 2005. The defined daily dose (DDD) for each fluoroquinolone was computed according to World Health Organization criteria. To account for fluctuation in patient volume, DDD/1000 bed days was computed for each year of study. Association between DDD/1000 bed days for each fluoroquinolone and the susceptibility of Gram negative bacteria to ciprofloxacin was assessed using Pearson's Correlation Coefficient, r.
  
  
  RESULTS
  During the study period, there were 48,261 antibiograms, 347,931 DDD of fluoroquinolones, and 1,943,338 bed days. Use of fluoroquinolones among inpatients decreased from 237.2 DDD/1000 bed days in 2000 to 115.2 DDD/1000 bed days in 2005. With the exception of Enterobacter aerogenes, moxifloxacin use was negatively correlated with sensitivity among all 13 Gram negative species evaluated (r = -0.07 to -0.97). When the sensitivities of all Gram negative organisms were aggregated, all fluoroquinolones except moxifloxacin were associated with increased sensitivity (r = 0.486 to 1.000) while moxifloxacin was associated with decreased sensitivity (r = -0.464).
  
  
  CONCLUSIONS
  Moxifloxacin, while indicated for empiric treatment of community acquired pneumonia, may have important negative influence on local antibiotic sensitivities amongst Gram negative organisms. This effect was not shared by other commonly used members of the fluoroquinolone class.
authors.affiliation: Department of Emergency Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, Ohio 45267-0769, USA. ryanrj@ucmail.uc.edu
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Ryan
authors.forename: Chris
authors.initials: C
authors.lastname: Lindsell
authors.forename: Paul
authors.initials: P
authors.lastname: Sheehan
mesh_terms: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001372:Aza Compounds / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology; D017714:Community-Acquired Infections / Q000188:drug therapy; D024901:Drug Resistance, Multiple, Bacterial; D004363:Drug Utilization; D021902:Enterobacter aerogenes / Q000187:drug effects; D024841:Fluoroquinolones / Q000494:pharmacology*; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy*; D006801:Humans; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D010607:Pharmacy Service, Hospital; D018410:Pneumonia, Bacterial / Q000188:drug therapy; D011804:Quinolines / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D002939:Ciprofloxacin; D000077266:Moxifloxacin