755. Characterisation of Clostridium difficile Hospital Ward-Based Transmission Using Extensive Epidemiological Data and Molecular Typing
Session: Oral Abstract Session: Clostridium difficile: Detection, Transmission, and Treatment
Friday, October 21, 2011: 2:45 PM
Room: 151AB
Background: The endemic nature of Clostridium difficile infection (CDI) in hospitals has hindered the identification of transmission events and attempts to define epidemiological parameters. This has led to limited control despite costly prevention strategies. Genotyping by multi-locus sequence typing (MLST) reveals membership of distinct C. difficile lineages, each of which may be analysed for evidence of hospital transmission.

Methods: All C. difficile toxin enzyme immunoassay positive samples over 2.5 years from a geographically defined population of 600,000 persons underwent MLST. Sequence types (STs) were combined with admission and ward movement data from the region’s major hospitals. Potential infection sources for each case were defined by prior ward-based contact with other cases sharing the same ST. Networks of cases and potential transmission events were constructed for each ST.

Results: 1274 isolates of 69 STs were studied. According to MLST, no more than 25% of cases were plausibly linked to a potential ward-based inpatient source. Amongst the linked cases identified, most ‘infection’ times between potential donor CDI and putative onward transmission to a recipient were <1 week (160/269,59%) with few >8 weeks(20/269,7%), while most incubation times in recipients were <4 weeks (149/269,55%), with few >12 weeks (38/269,14%). There was little evidence to link long term ward contamination (i.e. following discharge of cases) to transmission.

Conclusion: Our findings showing new CDIs linked to recent inpatient contacts provide support for robust infection control measures. However, having implemented such interventions in a large hospital group, ward-based contact with symptomatic enzyme immunoassay positive patients cannot account for the majority of CDI cases.


Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

David Eyre1, A. Sarah Walker, PhD1, David Wyllie1, Kate Dingle1, Rosalind Harding1, Lily O'Connor1, David Griffiths1, Ali Vaughan1, John Finney1, Mark Wilcox2, Derrick Crook, MB BCh3 and Tim Peto, MB BS, DPhil1, (1)NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom, (2)Leeds Teaching Hospitals & University of Leeds, Leeds, United Kingdom, (3)University of Oxford NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom

Disclosures:

D. Eyre, None

A. S. Walker, None

D. Wyllie, None

K. Dingle, None

R. Harding, None

L. O'Connor, None

D. Griffiths, None

A. Vaughan, None

J. Finney, None

M. Wilcox, bioMerieux: Consultant and Grant Investigator, Consulting fee, Research grant and Support to attend meetings
Optimer Pharmaceuticals: Consultant and Grant Investigator, Consulting fee, Research grant and Support to attend meetings
Novacta: Consultant and Grant Investigator, Consulting fee, Research grant and Support to attend meetings
Pfizer: Consultant and Grant Investigator, Consulting fee, Research grant and Support to attend meetings
Summit: Consultant and Grant Investigator, Consulting fee, Research grant and Support to attend meetings
The Medicines Company: Consultant and Grant Investigator, Consulting fee, Research grant and Support to attend meetings
Viropharma: Consultant and Grant Investigator, Consulting fee, Research grant and Support to attend meetings

D. Crook, Optimer Pharmaceuticals: Investigator and Scientific Advisor, Consulting fee and Institution received per-case funding to support trial patient expenses

T. Peto, Optimer Pharmaceuticals: Scientific Advisor, Consulting fee

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.