Severity and frequency of community-onset Clostridium difficile infection on an Australian tertiary referral hospital campus

• 29% of cases of Clostridum difficile infection (CDI) at a large tertiary hospital campus in Sydney, Australia were of community onset.
• Community onset Clostridum difficile infection has previously been considered to be a milder entitiy than hospital aquired infection but our study showed that markers of severity and outcomes were similar between the two groups.
• Overall 30 day mortality for the two groups was 9%.
• The community onset infection group were less likely to have the traditional risk factors of antibiotic use, proton pump inhibitor use or hospital contact.
• Given the difficulties with predicting community onset infection using traditional risk factors, we recommend that all patients with diarrheoa being investigated in emergency departments and community practise are tested for Clostridium difficile infection.

SummaryBackgroundClostridium 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.MethodsThis 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.ResultsOne 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%.ConclusionsCommunity-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.