title: Large hospital outbreak of KPC-2-producing Klebsiella pneumoniae: investigating mortality and the impact of screening for KPC-2 with polymerase chain reaction.
abstract: BACKGROUND
  Multi-drug-resistant Klebsiella pneumoniae carbapenemase (KPC)-2-producing K. pneumoniae are an increasing cause of healthcare-associated infections worldwide.
  
  
  OBJECTIVE
  To investigate the impact of clinical infection on mortality, and examine the effect of use of KPC-2-specific polymerase chain reaction (PCR) on the time to contact isolation during an outbreak.
  
  
  METHODS
  Cases were defined as patients clinically infected or colonized with KPC-2-producing K. pneumoniae between June 2010 and July 2012. Cases were described by demographic and health characteristics, and the association between infection and mortality, adjusted for comorbidities and demographic characteristics, was determined using Poisson regression with robust standard errors. A comparison was made between the time to contact isolation with a culture-based method and PCR using Wilcoxon's rank sum test.
  
  
  RESULTS
  Of 72 cases detected, 17 (24%) had undergone transplantation and 21 (29%) had a malignancy. Overall, 35 (49%) cases were clinically infected, with pneumonia and sepsis being the most common infections. Infection was an independent risk factor for mortality (risk ratio 1.67, 95% confidence interval 0.99-2.82). The median time to contact isolation was 1.5 days (range 0-21 days) using PCR and 5.0 days (range 0-39 days) using culture-based methods (P = 0.003). Intermittent negative tests were observed in 48% (14/29) of cases tested using culture-based methods.
  
  
  CONCLUSIONS
  KPC-2-producing K. pneumoniae mainly affect severely ill patients. Half of the cases developed clinical infection, associated with increased risk of death. As PCR accelerates isolation and provides the opportunity for preventive measures in colonized cases, its use should be implemented promptly during outbreaks. Further studies are needed to enhance knowledge about KPC detection patterns and to adjust screening guidelines.
authors.affiliation: Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany; European Programme for Intervention Training, European Centre for Disease Prevention and Control, Stockholm, Sweden. Electronic address: tanyaducomble@ymail.com.
authors.forename: T
authors.initials: T
authors.lastname: Ducomble
authors.affiliation: Hospital Hygiene Staff Unit, Leipzig University Hospital, Leipzig, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Faucheux
authors.affiliation: Local Public Health Department, Leipzig, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Helbig
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Leipzig University Hospital, Leipzig, Germany.
authors.forename: U X
authors.initials: UX
authors.lastname: Kaisers
authors.affiliation: Institute for Medical Microbiology and Epidemiology of Infectious Diseases, Leipzig University Hospital, Leipzig, Germany.
authors.forename: B
authors.initials: B
authors.lastname: König
authors.affiliation: Hospital Hygiene Staff Unit, Leipzig University Hospital, Leipzig, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Knaust
authors.affiliation: Division of Infectious Diseases and Tropical Medicine, Department of Gastroenterology and Rheumatology, University Hospital Leipzig, Leipzig, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Lübbert
authors.affiliation: Local Public Health Department, Leipzig, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Möller
authors.affiliation: Hospital Hygiene Staff Unit, Leipzig University Hospital, Leipzig, Germany; Institute for Medical Microbiology and Epidemiology of Infectious Diseases, Leipzig University Hospital, Leipzig, Germany.
authors.forename: A C
authors.initials: AC
authors.lastname: Rodloff
authors.affiliation: Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Schweickert
authors.affiliation: Department for Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Eckmanns
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology*; D004196:Disease Outbreaks; D005260:Female; D006115:Greece / Q000453:epidemiology; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology* / Q000382:microbiology*; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D012189:Retrospective Studies; D001618:beta-Lactamases / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D001618:beta-Lactamases; C547585:beta-lactamase KPC-2, Klebsiella pneumoniae
keywords: Carriage; Colonization; Healthcare-associated; Infection; Klebsiella pneumoniae carbapenemase; Length of stay; Mortality; Outbreak; Polymerase chain reaction; Resistance