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A Blinded Comparison of Three Laboratory Protocols for the Identification of Patients Colonized With Methicillin-Resistant Staphylococcus aureus

Published online by Cambridge University Press:  02 January 2015

Michael Gardam ,
James Brunton ,
Barbara Willey ,
Allison McGeer ,
Donald Low  and
John Conly
Michael Gardam*
Affiliation:
Infection Prevention and Control Unit, Department of Microbiology, Toronto Medical Laboratories University Health Network, University of Toronto, Toronto, Ontario, Canada
James Brunton
Affiliation:
Infection Prevention and Control Unit, Department of Microbiology, Toronto Medical Laboratories University Health Network, University of Toronto, Toronto, Ontario, Canada
Barbara Willey
Affiliation:
Department of Microbiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
Allison McGeer
Affiliation:
Department of Microbiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
Donald Low
Affiliation:
Department of Microbiology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
John Conly
Affiliation:
Infection Prevention and Control Unit, Department of Microbiology, Toronto Medical Laboratories University Health Network, University of Toronto, Toronto, Ontario, Canada
*
200 Elizabeth St, NUW 13-132, Toronto General Hospital, University Health Network, Toronto, Ontario M5G 2C4, Canada
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Abstract

Objective:

To compare three laboratory screening protocols for the detection of methicillin-resistant Staphylococcus aureus (MRSA) from surveillance specimens (mannitol-salt agar containing 2 μg/mL of oxacillin [MSA-2], mannitol-salt agar containing 4 μg/mL of oxacillin [MSA-4], and a broth-containing protocol as recommended by the American Society for Microbiology [M-ASM]).

Design:

Blinded comparative laboratory study and cost analysis.

Setting:

University-affiliated microbiology laboratory.

Methods:

Outcome measurements included rate of detection of MRSA-positive specimens and patients, turnaround time, and media and technologist costs. All MRSA culture swabs obtained from any patient site from November 1998 to April 1999 were included.

Results:

The M-ASM protocol detected between 19.1% and 32.0% more MRSA-positive specimens and between 13.3% and 23.3% more MRSA-positive patients per surveillance event than the MSA-4 and MSA-2 protocols, respectively. There was no difference in positive-culture reporting time between the M-ASM and MSA-4 protocols. The broth-containing protocol was 2- to 2.5-fold more expensive than the simpler protocols, taking into account media and laboratory personnel costs.

Conclusions:

It remains to be determined whether it is cost beneficial for a hospital to adopt the M-ASM, as the potential cost of MRSA transmission from unidentified MRSA-colonized patients is unknown. A broth-containing protocol should be considered the gold standard in future studies examining newer MRSA screening protocols.

Type
Original Articles
Information
Infection Control & Hospital Epidemiology , Volume 22 , Issue 3 , March 2001 , pp. 152 - 156
Copyright
Copyright © The Society for Healthcare Epidemiology of America 2001

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