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Prevalence of asymptomatic Clostridium difficile colonization in tertiary hospital patients in Australia


Despite the importance of C. difficile infection (CDI) as a cause of hospital-acquired diarrhea, few studies have investigated the prevalence of asymptomatic C. difficile colonization in a broad cross-section of the general hospital patient population over multiple years and seasons.


To estimate the prevalence of asymptomatic C. difficile colonization of tertiary hospitals in different Australian States during six time-periods (late summer [Feb-Mar] and late winter [Aug-Sep]) 2012-2014 and to describe the diversity of PCR ribotypes isolated from asymptomatic patients.


A three-year repeated cross-sectional study with biannual surveys of randomly selected adult patients from all care wards in tertiary hospitals in Australia was conducted. Stool specimens were cultured for C. difficile and isolates were characterized by PCR ribotyping. Overall prevalence of asymptomatic C. difficile colonization, hospital and time-period specific prevalences were calculated and compared using logistic regression.


Asymptomatic C. difficile colonization was identified in 112/1417 (7.90%; 95% CI 6.55–9.43) patients during the study period. Asymptomatic C. difficile colonization prevalence was at its highest in Feb-Mar 2012 (11.95%; 95% CI 8.46-16.22), whereas the lowest prevalence was observed in Aug-Sep 2014 (5.84%; 95% CI 3.30-9.44). A seasonal pattern characterized by lower prevalence in late winter (OR 0.63; 95% CI 0.42–0.94) was identified. The majority of the isolates (77.55%) were toxigenic C. difficile strains, PCR 014 and 018 were the most frequent toxigenic strains isolated.


High variability of asymptomatic C. difficile colonization prevalence was observed across seasons. The majority of the asymptomatic C. difficile infected patients were colonized by toxigenic strains.

*The study was funded by a NHRMC project grant (APP1006243).

Disclosure of interest

None declared.

Author information

Correspondence to L Furuya Kanamori.

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  • Lower Prevalence
  • Clostridium Difficile
  • Hospital Patient
  • Late Winter
  • Tertiary Hospital