title: Asymptomatic carriers of toxigenic C. difficile in long-term care facilities: a meta-analysis of prevalence and risk factors.
abstract: BACKGROUND
  The impact of Clostridium difficile colonization in C. difficile infection (CDI) is inadequately explored. As a result, asymptomatic carriage is not considered in the development of infection control policies and the burden of carrier state in long-term care facilities (LTCFs) is unknown.
  
  
  OBJECTIVE
  To explore the epidemiology of C. difficile colonization in LTCFs, identify predisposing factors and describe its impact on healthcare management.
  
  
  METHODS
  PubMed, Embase and Web of Science (up to June 2014) without language restriction, complemented by reference lists of eligible studies.
  
  
  METHODS
  All studies providing extractable data on the prevalence of toxigenic C. difficile colonization among asymptomatic residents in LTCFs.
  
  
  METHODS
  Two authors extracted data independently.
  
  
  METHODS
  The pooled colonization estimates were calculated using the double arcsine methodology and reported along with their 95% random-effects confidence intervals (CIs), using DerSimonian-Laird weights. We assessed the impact of patient-level covariates on the risk of colonization and effects were reported as odds ratios (OR, 95% CI). We used the colonization estimates to simulate the effective reproduction number R through a Monte Carlo technique.
  
  
  RESULTS
  Based on data from 9 eligible studies that met the specified criteria and included 1,371 subjects, we found that 14.8% (95%CI 7.6%-24.0%) of LTCF residents are asymptomatic carriers of toxigenic C. difficile. Colonization estimates were significantly higher in facilities with prior CDI outbreak (30.1% vs. 6.5%, p = 0.01). Patient history of CDI (OR 6.07; 95% CI 2.06-17.88; effect derived from 3 studies), prior hospitalization (OR 2.11; 95% CI 1.08-4.13; derived from 3 studies) and antimicrobial use within previous 3 months (OR 3.68; 95% CI 2.04-6.62; derived from 4 studies) were associated with colonization. The predicted colonization rate at admission was 8.9%.
  
  
  CONCLUSIONS
  Asymptomatic carriage of toxigenic C. difficile represents a significant burden in LTCFs and is associated with prior CDI outbreaks in the facility, a history of CDI, prior hospitalization and antimicrobial use. These findings can impact infection control measures at LTCFs.
authors.affiliation: Infectious Diseases Division, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America.
authors.forename: Panayiotis D
authors.initials: PD
authors.lastname: Ziakas
authors.affiliation: Infectious Diseases Division, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America.
authors.forename: Ioannis M
authors.initials: IM
authors.lastname: Zacharioudakis
authors.affiliation: Infectious Diseases Division, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America.
authors.forename: Fainareti N
authors.initials: FN
authors.lastname: Zervou
authors.affiliation: Infectious Diseases Division, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America.
authors.forename: Christos
authors.initials: C
authors.lastname: Grigoras
authors.affiliation: Infectious Diseases Division, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America.
authors.forename: Elina Eleftheria
authors.initials: EE
authors.lastname: Pliakos
authors.affiliation: Infectious Diseases Division, Warren Alpert Medical School of Brown University, Providence, Rhode Island, United States of America.
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Mylonakis
mesh_terms: D002353:Carrier State / Q000453:epidemiology*; D016360:Clostridioides difficile; D016208:Databases, Factual; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology* / Q000635:transmission*; D006801:Humans; D017053:Infection Control; D008134:Long-Term Care; D015995:Prevalence; D012307:Risk Factors