Pulsed-field gel electrophoresis typing of methicillin-resistant Staphylococcus aureus in Canada: An exercise in the sta

1. Pulsed-field gel electrophoresis typing of methicillin-resistant Staphylococcus aureus in Canada: An exercise in the standardization of methods and nomenclature

2. J. Campbell, J. D Spreitzer, M.R Mulvey, L.K. Ng and the MRSA PFGE Working Group MRSA: Do you see what I see?

3. Introduction PFGE �Gold Standard� Standardized protocols allows laboratories to compare fingerprints Gel analysis software

4. History of Standardization in Canada 1999 MRSA panel distributed to 15 labs Individual laboratories in-house PFGE protocols and interpretation 54% made at least one error Inter-laboratory image comparison impossible

5. Development of Standardized Protocol MRSA subcommittee created standardized PFGE protocol New proficiency panel distributed Less than 1.7% deviation in band positions between sites Inter-laboratory image comparison possible

6. Methods Participants Exercise distributed to 18 hospital and provincial laboratories Bacterial Strains MRSA strains provided by Canadian Nososcomial Infection Surveillance Program (CNISP) Salmonella ser. Braenderup H9812 molecular size standard provided by Dr. Bala Swaminathan (CDC, Atlanta, Georgia, USA)

7. Study Design 7 genetically unrelated MRSA isolates

8. Study Design Distribution package CDC Salmonella PFGE protocol S. Braenderup H9812 size standard plugs and strain Canadian MRSA PFGE protocol Proficiency strains Customized database Fingerprint bundle file (647 unique patterns)

9. Study Design Participating Sites� Responsibilities Develop Salmonella PFGE protocol with S. Braenderup H9812 Type proficiency strains using MRSA standardized PFGE protocol Import and analyze images Compare to national database Report designations

10. Study Design Coordinating lab responsibilities Review designations Issue report Work with participating site�s to resolve problems

11. Pattern Interpretation Minor error Major error

12. Results 13 of the 18 laboratories took part in the exercise Three laboratories correctly determined all seven isolates designations Six sites required a second submission Four sites required additional guidance and a third submission

13. Results for All Pattern Submissions

15. Comparison of the pattern profiles most commonly selected for MRSA proficiency isolate PS1

16. Comparison of the pattern profile most commonly selected for MRSA proficiency isolate PS5

17. Conclusions Standardization of methods and nomenclature Areas that require attention Develop guidelines for band interpretation Working with digital PFGE patterns Additional training in database utilization

18. Participating Sites Hospital Laboratories Christine Watt, Sunnybrook and Women�s College Health Sciences Centre, Toronto, ON Helen Dedier, The Toronto Hospital, Toronto, ON Padman Jayaratne and Candy Rutherford, Hamilton Health Sciences Corporation, Hamilton, ON Gary Peters, London Health Sciences Centre, London, ON Michelle Alfa and Pat DeGagne, St. Boniface General Hospital, Winnipeg, MB Lori Takada, Health Sciences Centre, Winnipeg, MB Manickam Kanchana, Regina General Hospital, Regina, SK Sameer Elsayed and Nina Hamilton, Calgary, Laboratory Services, Calgary, AB Susan Porter, Vancouver General Hospital, Vancouver, BC Provincial Laboratories Marina Lombos, Ontario Ministry of Health, Etobicoke, ON John Wylie, Cadham Provincial Health Laboratory, Winnipeg, MB Linda Chui, Alberta Provincial Health Laboratory, Edmonton, AB Tazim Rahim, British Columbia Centres for Disease Control, Vancouver, BC National Microbiology Laboratory Jennifer Campbell Dave Spreitzer