Asymptomatic Clostridium difficile colonisation in two Australian tertiary hospitals, 2012-2014: A prospective, repeated cross-sectional study

Furuya-Kanamori L1, Clements AC2, Foster NF3, Huber CA4, Hong S5, Harris-Brown T4, Yakob L6, Paterson DL4, Riley TV3.Asymptomatic Clostridium difficile colonisation in two Australian tertiary hospitals, 2012-2014: A prospective, repeated cross-sectional study. Clin Microb Infect 2016. doi: 10.1016/j.cmi.2016.08.030


Abstract

To investigate the prevalence and risk factors for asymptomatic toxigenic (TCD) and nontoxigenic Clostridium difficile (NTCD) colonization in a broad cross section of the general hospital population over a 3-year period. Patients without diarrhoea admitted to two Australian tertiary hospitals were randomly selected through six repeated cross-sectional surveys conducted between 2012 and 2014. Stool specimens were cultured under anaerobic conditions, and C. difficile isolates were tested for the presence of toxin genes and ribotyped. Patients were then grouped into noncolonized, TCD colonized or NTCD colonized for identifying risk factors using multinomial logistic regression models. A total of 1380 asymptomatic patients were enrolled; 76 patients (5.5%) were TCD colonized and 28 (2.0%) were NTCD colonized. There was a decreasing annual trend in TCD colonization, and asymptomatic colonization was more prevalent during the summer than winter months. TCD colonization was associated with gastro-oesophageal reflux disease (relative risk ratio (RRR) = 2.20; 95% confidence interval (CI) 1.17-4.14), higher number of admissions in the previous year (RRR = 1.24; 95% CI 1.10-1.39) and antimicrobial exposure during the current admission (RRR = 2.78; 95% CI 1.23-6.28). NTCD colonization was associated with chronic obstructive pulmonary disease (RRR = 3.88; 95% CI 1.66-9.07) and chronic kidney failure (RRR = 5.78; 95% CI 2.29-14.59). Forty-eight different ribotypes were identified, with 014/020 (n = 23), 018 (n = 10) and 056 (n = 6) being the most commonly isolated. Risk factors differ between patients with asymptomatic colonization by toxigenic and nontoxigenic strains. Given that morbidity is largely driven by toxigenic strains, this novel finding has important implications for disease control and prevention.

  • 1Research School of Population Health, The Australian National University, Canberra, Australian Capital Territory, Australia.
  • 2Research School of Population Health, The Australian National University, Canberra, Australian Capital Territory, Australia. Electronic address: director.rsph@anu.edu.au.
  • 3Microbiology & Immunology, School of Pathology & Laboratory Medicine, The University of Western Australia, Australia; Department of Microbiology, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Nedlands, WA, Australia.
  • 4UQ Centre for Clinical Research, The University of Queensland, Herston, Queensland, Australia.
  • 5Microbiology & Immunology, School of Pathology & Laboratory Medicine, The University of Western Australia, Australia.
  • 6Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom.

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