title: A large outbreak of Clostridium difficile-associated disease with an unexpected proportion of deaths and colectomies at a teaching hospital following increased fluoroquinolone use.
abstract: OBJECTIVE
  Fluoroquinolones have not been frequently implicated as a cause of Clostridium difficile outbreaks. Nosocomial C. difficile infections increased from 2.7 to 6.8 cases per 1000 discharges (P < .001). During the first 2 years of the outbreak, there were 253 nosocomial C. difficile infections; of these, 26 resulted in colectomy and 18 resulted in death. We conducted an investigation of a large C. difficile outbreak in our hospital to identify risk factors and characterize the outbreak.
  
  
  METHODS
  A retrospective case-control study of case-patients with C. difficile infection from January 2000 through April 2001 and control-patients matched by date of hospital admission, type of medical service, and length of stay; an analysis of inpatient antibiotic use; and antibiotic susceptibility testing and molecular subtyping of isolates were performed.
  
  
  RESULTS
  On logistic regression analysis, clindamycin (odds ratio [OR], 4.8; 95% confidence interval [CI95], 1.9-12.0), ceftriaxone (OR, 5.4; CI95, 1.8-15.8), and levofloxacin (OR, 2.0; CI95, 1.2-3.3) were independently associated with infection. The etiologic fractions for these three agents were 10.0%, 6.7%, and 30.8%, respectively. Fluoroquinolone use increased before the onset of the outbreak (P < .001); 59% of case-patients and 41% of control-patients had received this antibiotic class. The outbreak was polyclonal, although 52% of isolates belonged to two highly related molecular subtypes.
  
  
  CONCLUSIONS
  Exposure to levofloxacin was an independent risk factor for C. difficile-associated diarrhea and appeared to contribute substantially to the outbreak. Restricted use of levofloxacin and the other implicated antibiotics may be required to control the outbreak
authors.affiliation: Division of Hospital Epidemiology and Infection Control, University of Pittsburgh Medical Center, Presbyterian Campus, Pittsburgh, Pennsylvania 15213, USA. mutoca@msx.upmc.edu
authors.forename: Carlene A
authors.initials: CA
authors.lastname: Muto
authors.forename: Marian
authors.initials: M
authors.lastname: Pokrywka
authors.forename: Kathleen
authors.initials: K
authors.lastname: Shutt
authors.forename: Aaron B
authors.initials: AB
authors.lastname: Mendelsohn
authors.forename: Kathy
authors.initials: K
authors.lastname: Nouri
authors.forename: Kathy
authors.initials: K
authors.lastname: Posey
authors.forename: Terri
authors.initials: T
authors.lastname: Roberts
authors.forename: Karen
authors.initials: K
authors.lastname: Croyle
authors.forename: Sharon
authors.initials: S
authors.lastname: Krystofiak
authors.forename: Sujata
authors.initials: S
authors.lastname: Patel-Brown
authors.forename: A William
authors.initials: AW
authors.lastname: Pasculle
authors.forename: David L
authors.initials: DL
authors.lastname: Paterson
authors.forename: Melissa
authors.initials: M
authors.lastname: Saul
authors.forename: Lee H
authors.initials: LH
authors.lastname: Harrison
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000627:therapeutic use; D016022:Case-Control Studies; D002423:Cause of Death; D002981:Clindamycin / Q000009:adverse effects / Q000627:therapeutic use; D016360:Clostridioides difficile / Q000302:isolation & purification*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D003967:Diarrhea / Q000139:chemically induced / Q000382:microbiology; D004196:Disease Outbreaks; D004761:Enterocolitis, Pseudomembranous / Q000401:mortality / Q000517:prevention & control*; D005260:Female; D024841:Fluoroquinolones / Q000009:adverse effects / Q000627:therapeutic use*; D006784:Hospitals, Teaching; D006801:Humans; D064704:Levofloxacin; D016015:Logistic Models; D008297:Male; D015242:Ofloxacin / Q000009:adverse effects / Q000627:therapeutic use; D010414:Pennsylvania / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D002981:Clindamycin; D064704:Levofloxacin; D015242:Ofloxacin