title: Outbreak of catheter-associated Klebsiella oxytoca and Enterobacter cloacae bloodstream infections in an oncology chemotherapy center.
abstract: BACKGROUND
  In March 2004, the Chicago Department of Public Health was notified of a cluster of bloodstream infections with Klebsiella oxytoca and Enterobacter cloacae at a chemotherapy center. Our purpose was to identify the source of the outbreak and prevent further cases.
  
  
  METHODS
  The investigation included 103 oncology patients seen at an outpatient oncology chemotherapy center in Chicago during the 16 days before its closure. The outbreak investigation included case identification, retrospective cohort study, review of medical records, microbiologic testing of blood specimens, environmental cultures, and pulsed-field gel electrophoresis. The main outcome measure was infection with K oxytoca, E cloacae, or both, and the Mantel-Haenszel chi(2) test was used to assess risk of infection in relation to presence of central venous catheter.
  
  
  RESULTS
  Among the 103 patients, risk of infection was associated with the presence of central venous catheter (relative risk undefined, P<.001). Twenty-seven patients had blood cultures that grew K oxytoca, E cloacae, or both, and all had central venous catheters that were flushed with isotonic sodium chloride solution at the clinic from February 17 through March 3, 2004. Isolates of K oxytoca and E cloacae were matched by pulsed-field gel electrophoresis to K oxytoca and E cloacae isolates obtained from multiple predrawn syringes and from the intravenous fluid and administration set in use in the clinic at the time of its closing.
  
  
  CONCLUSIONS
  The injection of contaminated isotonic sodium chloride solution through the venous catheters of attendees at the clinic likely provided the opportunity for bloodstream infections in these 27 case patients. This outbreak highlights the need for continued emphasis on safe injection practices and suggests the need for guidelines and recommendations tailored to outpatient settings.
authors.affiliation: Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, GA, USA.
authors.forename: John T
authors.initials: JT
authors.lastname: Watson
authors.forename: Roderick C
authors.initials: RC
authors.lastname: Jones
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Siston
authors.forename: Julio R
authors.initials: JR
authors.lastname: Fernandez
authors.forename: Karen
authors.initials: K
authors.lastname: Martin
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Beck
authors.forename: Steven
authors.initials: S
authors.lastname: Sokalski
authors.forename: Bette J
authors.initials: BJ
authors.lastname: Jensen
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Arduino
authors.forename: Arjun
authors.initials: A
authors.lastname: Srinivasan
authors.forename: Susan I
authors.initials: SI
authors.lastname: Gerber
mesh_terms: D000328:Adult; D000368:Aged; D000554:Ambulatory Care Facilities; D000970:Antineoplastic Agents / Q000008:administration & dosage; D016470:Bacteremia / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology; D002173:Cancer Care Facilities; D002405:Catheterization, Central Venous / Q000009:adverse effects / Q000295:instrumentation / Q000451:nursing; D002641:Chicago / Q000453:epidemiology; D015331:Cohort Studies; D003428:Cross Infection / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology; D004196:Disease Outbreaks; D016972:Enterobacter cloacae / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000453:epidemiology*; D004866:Equipment Contamination; D017743:Equipment Reuse; D005260:Female; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology*; D041121:Klebsiella oxytoca / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy; D012189:Retrospective Studies
chemical_list: D000970:Antineoplastic Agents