title: An Outbreak of Clostridium difficile Ribotype 027 Associated with Length of Stay in the Intensive Care Unit and Use of Selective Decontamination of the Digestive Tract: A Case Control Study.
abstract: BACKGROUND
  An outbreak of Clostridium difficile ribotype 027 infection (CDI) occurred at an university hospital, involving 19 departments. To determine what hospital-associated factors drove the outbreak of this particular strain we performed a case-control study.
  
  
  METHODS
  Cases (n = 79), diagnosed with CDI due to C. difficile ribotype 027 were matched for age and treating medical specialty to four control patients (n = 316). Patients diagnosed with CDI due to other ribotypes were included as a second control group. A random selection of C. difficile ribotype 027 strains (n = 10) was genotyped by Whole Genome Sequencing (WGS).
  
  
  RESULTS
  WGS showed the outbreak was likely caused by a single strain of C. difficile (two or less single-nucleotide variants between isolates). Ninety-five percent of cases had used antibiotics, compared to 56% of controls. Previous admission to the intensive care unit (ICU) (OR: 2.4, 95% CI 1.0-5.6), longer length of stay (LOS), and recent hospital admission were associated with CDI ribotype 027. Cases were less likely to have been admitted to a ward with a known isolated CDI patient (OR: 0.2, 95% CI 0.1-0.6). Analysis of patients who stayed at the ICU (35 cases; 51 controls), indicated that the use of selective decontamination of the digestive tract (SDD) and a longer LOS in the ICU were associated with CDI risk.
  
  
  CONCLUSIONS
  In this large outbreak, any antibiotic use, including SDD use, appeared as a prerequisite for acquisition of the outbreak strain. The role of use of SDD and prolonged stay on the ICU could not be disentangled, but both factors can play a biologically plausible role in C. difficile acquisition and infection.
authors.affiliation: Department of Medical Microbiology and Infection Control, VU University medical center, Amsterdam, The Netherlands.|Department of Gastroenterology and Hepatology, VU University medical center, Amsterdam, The Netherlands.
authors.forename: Yvette H
authors.initials: YH
authors.lastname: van Beurden
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.|Department of Endocrinology and Metabolic Diseases, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Olaf M
authors.initials: OM
authors.lastname: Dekkers
authors.affiliation: Department of Internal Medicine, VU University medical center, Amsterdam, The Netherlands.
authors.forename: Marije K
authors.initials: MK
authors.lastname: Bomers
authors.affiliation: Department of Medical Microbiology and Infection Control, VU University medical center, Amsterdam, The Netherlands.
authors.forename: Annie M
authors.initials: AM
authors.lastname: Kaiser
authors.affiliation: Department of Medical Microbiology and Infection Control, VU University medical center, Amsterdam, The Netherlands.
authors.forename: Robin
authors.initials: R
authors.lastname: van Houdt
authors.affiliation: Department of Medical Microbiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Cornelis W
authors.initials: CW
authors.lastname: Knetsch
authors.affiliation: Department of Intensive Care, VU University medical center, Amsterdam, The Netherlands.
authors.forename: Armand R J
authors.initials: AR
authors.lastname: Girbes
authors.affiliation: Department of Gastroenterology and Hepatology, VU University medical center, Amsterdam, The Netherlands.
authors.forename: Chris J J
authors.initials: CJ
authors.lastname: Mulder
authors.affiliation: Department of Medical Microbiology and Infection Control, VU University medical center, Amsterdam, The Netherlands.
authors.forename: Christina M J E
authors.initials: CM
authors.lastname: Vandenbroucke-Grauls
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D016360:Clostridioides difficile / Q000145:classification* / Q000235:genetics*; D003015:Clostridium Infections / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology / Q000401:mortality; D003666:Decontamination / Q000379:methods; D004196:Disease Outbreaks; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology; D006785:Hospitals, University; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D021521:Ribotyping; D012307:Risk Factors