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Pulsedfield gel electrophoresis typing of methicillinresistant Staphylococcus aureus in Canada: An e

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13 of the 18 laboratories took part in the exercise ... Sameer Elsayed and Nina Hamilton, Calgary, Laboratory Services, Calgary, AB ... – PowerPoint PPT presentation

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Title: Pulsedfield gel electrophoresis typing of methicillinresistant Staphylococcus aureus in Canada: An e


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

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

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

Mulvey et al. 2001. J Clin Microbiol.
393481-3485.
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

Mulvey et al. 2001. J Clin Microbiol.
393481-3485.
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

Unique Patterns in Database
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 sites 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
74
11
14
14
First Submission Results
Unique in database
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
  • Comments were quite favorable

18
Participating Sites
  • Hospital Laboratories
  • Christine Watt, Sunnybrook and Womens 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
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