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