title: Severity and frequency of community-onset Clostridium difficile infection on an Australian tertiary referral hospital campus.
abstract: BACKGROUND
  Clostridium difficile infection (CDI) is increasingly being found in populations without traditional risk factors. We compared the relative frequency, risk factors, severity, and outcomes of community-onset CDI with hospital-acquired infection.
  
  
  METHODS
  This was a retrospective, observational study of CDI at a tertiary hospital campus in Sydney, Australia. Patients aged 15 years and older with a first episode of CDI from January 1 to December 31, 2011 were included. CDI was defined as the presence of diarrhoea with a positive enzyme immunoassay in conjunction with a positive cell cytotoxicity assay, toxin culture, or organism culture. Main outcome measures were onset of infection (hospital or community), risk factors, markers of severity, and outcomes for the two groups.
  
  
  RESULTS
  One hundred and twenty-nine cases of CDI infection were identified, of which 38 (29%) were community-onset. The community-onset infection group were less likely to have a recent history of antibiotic use (66% vs. 98%; p<0.001) or proton pump inhibitor use (38% vs. 69%; p=0.03) than the hospital-acquired infection group. Markers of severity and outcomes were similar in the two groups, with an overall mortality of 9%.
  
  
  CONCLUSIONS
  Community-onset CDI accounts for a large proportion of C. difficile infections and has a similar potential for severe disease as hospital-acquired infection. Using a history of previous antibiotic use, proton pump inhibitor use, or recent hospitalization to predict cases is unreliable. We recommend that patients with diarrhoea being investigated in emergency departments and community practice are tested for Clostridium difficile infection.
authors.affiliation: Infectious Diseases Department, Prince of Wales Hospital, Randwick, New South Wales, Australia; Prince of Wales Clinical School, University of New South Wales, Randwick, New South Wales, Australia. Electronic address: penepoly@hotmail.com.
authors.forename: Penny
authors.initials: P
authors.lastname: Clohessy
authors.affiliation: Microbiology Department, SEALS, Prince of Wales Hospital, Randwick, New South Wales, Australia.
authors.forename: Juan
authors.initials: J
authors.lastname: Merif
authors.affiliation: Infectious Diseases Department, Prince of Wales Hospital, Randwick, New South Wales, Australia; Prince of Wales Clinical School, University of New South Wales, Randwick, New South Wales, Australia.
authors.forename: Jeffrey John
authors.initials: JJ
authors.lastname: Post
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001315:Australia; D016360:Clostridioides difficile; D003015:Clostridium Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000453:epidemiology; D003428:Cross Infection / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D062606:Tertiary Care Centers; D055815:Young Adult
keywords: Clostridium difficile; Community onset; Frequency; Severity