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Angela Wigmore, K. Suh, N. Bruce, G. Garber, C. Chambers, Liz Van Horne,
V. Allen, C. Egan, K. Stockton, V. Roth
Nosocomial Clostridium difficile Infection (CDI): Things Are Not Always As They Seem
Disclosure
• None of the authors on this presentation have anything to disclose
• Clostridium difficile is an anaerobic gram positive spore forming bacterium
• It can cause a severe inflammatory colonic disease with a high morbidity and mortality
• Most commonly associated with health care, occurring in hospitals and other health care facilities
Clostridium difficile
https://www.google.ca/url?q=http://depts.washington.edu/molmicdx/mdx/tests/cdiff.shtml&sa=U&ei=UfR0U_KSC5GLqAbkvICwDw&ved=0CD8Q9QEwCQ&usg=AFQjCNGQZhKKxfnWU-b5v4xT29U_jWxFWA
Setting
• The Ottawa Hospital (TOH): A multi site tertiary care facility with 1,200 beds
• Most acute inpatient care is provided at 2 sites
Civic
Background
• CNISP CDI rates were stable between 1997- 2007 (0.66 and 0.73 per 1000 patient days, respectively)*
• Healthcare – associated CDI is frequent and of increasing severity
• CDI attributable mortality increased from 1.5% in 1997 to 5.3% in 2011 per 100 HA-CDI cases*
*Public Health Agency of Canada, CNISP, Clostridium difficile Associated Disease (CDAD) Surveillance
Issue
• 2012-2013 we experienced several prolonged
outbreaks on our in patient units despite reinforcement of:
-routine practises -prompt isolation of symptomatic patient -enhanced environmental cleaning with bleach -implementation of bedpan liner waste management transmission persisted
Issue Continued
• In spite the implementation of these measures as well as the increase in resources and energy the outbreaks were not terminated
• Several units continued to have an increase in nosocomial cases
• Public Health Ontario was asked to conduct a review
Definition
• Outbreak was defined as 3 or more geographically clustered cases of laboratory confirmed HA-CDI on one w/u within 7 day or 5 cases within 4 weeks
• Healthcare associated CDI was defined as onset of symptoms >72 hours after admission or symptoms present on admission with a previous admission in the preceding 8 weeks
Investigation
• Public Health Laboratory performed molecular typing of outbreak isolates
• Methodology used was pulse-field gel electrophoresis (PFGE)
• 41 isolates from 9 different outbreaks involving 48 patients (~3-9/outbreak) were typed
V CDI
CDI
CDI
CDI
CDI
CDI
CDI CDI
CDI
H
NAP 4
G
L M
NAP 1 E
NAP11
F
Floor Plan of An Outbreak Unit B
PFGE Typing
Different Same *Provided by Marina Lombos, Public Health Laboratory, Toronto, Ontario
Results • NAP-1 strain accounted for 39% of all isolates but was
the predominant strain in only one outbreak • 16 different PFGE patterns were identified • A median of 3 PFGE patterns was identified in each
outbreak (range 2-6) • Findings suggested that isolates from our outbreaks
at TOH were polyclonal
Outbreak Typing Results
Campus Unit No.
patients No. samples
typed No. unique
strains Predominant
Strain
General
A 5 4 2 none
B* 12 9 9 none
C* 9 8 6 none
D 9 8 5 none
E 3 2 2 none
Civic F* 10 10 3 NAP1
TOTAL 48 41 16 NAP1
* 2 outbreaks on each of these units
Lessons Learned
• Things are not always as they seem. HA cases that appear to be linked were caused by different strains of Clostridium difficile
• In spite of our findings basic infection prevention measures remain the cornerstone in reducing transmission of Clostridium difficile
Conclusion
• Prevention strategies need to shift with a greater focus on appropriate antimicrobial use
• Typing did not produce the results we expected leaving many questions still unanswered
• The epidemiology of CDI in the community also deserves further study.
Acknowledgements
I would also like to thank and recognize the
following individuals:
• Dr Gary Garber
• Cathy Egan
• Liz Van Horne
• Vanessa Allen
• Marina Lombos