Universal Surveillance for Methicillin-Resistant Staphylococcus aureus in 3 Affiliated Hospitals

18 March 2008 | Volume 148 Issue 6 | Pages 409-418

Background: The effect of large-scale expanded surveillance for methicillin-resistant Staphylococcus aureus (MRSA) on health care–associated MRSA disease is not known.

Objective: To examine the effect of 2 expanded surveillance interventions on MRSA disease.

Design: Observational study comparing rates of MRSA clinical disease during and after hospital admission in 3 consecutive periods: baseline (12 months), MRSA surveillance for all admissions to the intensive care unit (ICU) (12 months), and universal MRSA surveillance for all hospital admissions (21 months).

Setting: A 3-hospital, 850-bed organization with approximately 40 000 annual admissions.

Intervention: Polymerase chain reaction–based nasal surveillance for MRSA followed by topical decolonization therapy and contact isolation of patients who tested positive for MRSA.

Measurements: Poisson and segmented regression models were used to compare prevalence density of hospital-associated clinical MRSA disease (bloodstream, respiratory, urinary tract, and surgical site) in each period. Rates of bloodstream disease with methicillin-susceptible S. aureus were used as a control.

Results: The prevalence density of aggregate hospital-associated MRSA disease (all body sites) per 10 000 patient-days at baseline, during ICU surveillance, and during universal surveillance was 8.9 (95% CI, 7.6 to 10.4), 7.4 (CI, 6.1 to 9.0; P = 0.15 compared with baseline), and 3.9 (CI, 3.2 to 4.7; P < 0.001 compared with baseline and ICU surveillance), respectively. During universal surveillance, the prevalence density of MRSA infection at each body site had a statistically significant decrease compared with baseline. The methicillin-susceptible S. aureus bacteremia rate did not statistically significantly change during the 3 periods. In a segmented regression model, the aggregate hospital-associated MRSA disease prevalence density changed by –36.2% (CI, –65.4% to 9.8%; P = 0.17) from baseline to ICU surveillance and by –69.6% (CI, –89.2% to –19.6%]; P = 0.03) from baseline to universal surveillance. During universal surveillance, the MRSA disease rate decreased during hospitalization and in the 30 days after discharge; no further reduction occurred thereafter. Surveillance with clinical cultures would have identified 17.8% of actual MRSA patient-days, and ICU-based surveillance with polymerase chain reaction would have identified 33.3%.

Limitation: The findings rely on observational data.

Conclusion: The introduction of universal admission surveillance for MRSA was associated with a large reduction in MRSA disease during admission and 30 days after discharge.

Editors' Notes Context Efforts to reduce the frequency of methicillin-resistant Staphylococcus aureus (MRSA) infections have failed until now. Contribution After a baseline year, the authors screened all intensive care unit admissions for MRSA colonization using polymerase chain reaction. In year 3, they screened all hospital admissions. They placed patients who tested positive for MRSA on contact precautions. The prevalence density of MRSA clinical infection was 8.9, 7.4, and 3.9 per 10 000 patient-days in years 1, 2, and 3, respectively. Methicillin-sensitive S. aureus infection rates did not change. Caution There was no concomitant, unscreened control group. Implication Screening for MRSA colonization is associated with substantially reduced rates of MRSA clinical infection. —The Editors

 

Author and Article Information

From Evanston Northwestern Healthcare and Northwestern University Feinberg School of Medicine, Evanston, Illinois.

Acknowledgment: The authors thank Judson Vosburg and the Evanston Northwestern Healthcare administration for their support, Toni-Marie Gonzalzles for chart review, and Ilana Segal and Michael Klompas for thoughtful comments on the manuscript.

Potential Financial Conflicts of Interest: Consultancies: R.B. Thomson (GlaxoSmithKline), K.L. Kaul (Roche). Honoraria: A. Robicsek (Becton Dickinson), S.M. Paule (Becton Dickinson), R.B. Thomson (Becton Dickinson), K.L. Kaul (Roche, Becton Dickinson), L.R. Peterson (Becton Dickinson). Grants received: K.L. Kaul (Roche), L.R. Peterson (Becton Dickinson, Cepheid, 3M, Roche, Nanosphere). Grants pending: A. Robicsek (Becton Dickinson), L.R. Peterson (Becton Dickinson, Cepheid, 3M, Roche).

Reproducible Research Statement: Study protocol: Available from Dr. Peterson (e-mail, lancer{at}northwestern.edu). Statistical code: Available from Dr. Robicsek (e-mail, ari.robicsek{at}gmail.com). Data set: Available from Dr. Robicsek (e-mail, ari.robicsek{at}gmail.com).

Requests for Single Reprints: Lance R. Peterson, MD, Department of Pathology and Laboratory Medicine, Evanston Northwestern Healthcare, 2650 Ridge Avenue, Evanston, IL 60201; e-mail, lancer{at}northwestern.edu.

Current Author Addresses: Dr. Robicsek: Department of Medicine, Division of Infectious Diseases, Evanston Northwestern Healthcare, 2650 Ridge Avenue, Evanston, IL 60201.

Ms. Beaumont: Center on Outcomes, Research, and Education, Evanston Northwestern Healthcare, 2650 Ridge Avenue, Evanston, IL 60201.

Ms. Paule and Ms. Hacek: Department of Pathology and Laboratory Medicine, Division of Microbiology, Evanston Northwestern Healthcare, 2650 Ridge Avenue, Evanston, IL 60201.

Drs. Thompson, Kaul, and Peterson: Department of Pathology and Laboratory Medicine, Evanston Northwestern Healthcare, 2650 Ridge Avenue, Evanston, IL 60201.

Ms. King: Department of Risk Management, Evanston Northwestern Healthcare, 2650 Ridge Avenue, Evanston, IL 60201.

Author Contributions: Conception and design: A. Robicsek, S.M. Paule, D.M. Hacek, R.B. Thomson, K.L. Kaul, P. King, L.R. Peterson.

Analysis and interpretation of the data: A. Robicsek, J.L. Beaumont, S.M. Paule, D.M. Hacek, R.B. Thomson, K.L. Kaul, P. King, L.R. Peterson.

Drafting of the article: A. Robicsek, J.L. Beaumont, L.R. Peterson.

Critical revision of the article for important intellectual content: J.L. Beaumont, S.M. Paule, D.M. Hacek, R.B. Thomson, P. King, L.R. Peterson.

Final approval of the article: J.L. Beaumont, S.M. Paule, D.M. Hacek, R.B. Thomson, K.L. Kaul, P. King, L.R. Peterson.

Statistical expertise: J.L. Beaumont.

Obtaining of funding: P. King.

Administrative, technical, or logistic support: S.M. Paule, D.M. Hacek, R.B. Thomson, K.L. Kaul, L.R. Peterson.

Collection and assembly of data: S.M. Paule, K.L. Kaul, L.R. Peterson.

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