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IIR 05-123 – HSR Study

IIR 05-123
Predicting Antibiotic Resistant Bacteria Carriage at Hospital Admission
Eli N. Perencevich, MD MS BS
Baltimore VA Medical Center VA Maryland Health Care System, Baltimore, MD
Baltimore, MD
Funding Period: September 2006 - August 2009
Methicillin-resistant Staphylococcus aureus (MRSA) is an increasing problem in VA and other healthcare settings. Currently VA requires that MRSA surveillance cultures be obtained on all admissions. This approach is costly and could be improved if high-risk patients for MRSA could be identified and targeted for selective, targeted-MRSA screening. We have developed such a systematic approach and seek now to apply it in the VHA.

(1) create and validate a prediction rule to identify patients at high risk for colonization with MRSA upon of admission to an acute care VA hospital and (2) develop a mathematical model to test the cost effectiveness of MRSA screening in the VA health care system.

All patients admitted to the general medical and surgical wards of the acute care Baltimore VA Medical Center were approached for enrollment in this study and if consented were administered a questionnaire and swab cultures of the anterior nares (nasal). In addition, evidence of past exposures in the year preceding the current admission were collected from CPRS data extraction and minimal chart review, including antibiotic exposures, comorbid conditions, and previous admission history. A prediction rule for the presence of MRSA colonization was created using collected data. The effectiveness and cost-effectiveness of MRSA active surveillance will be assessed with mathematical models.

Out of the initial 598 patients enrolled, 585 underwent nasal cultures for MRSA. Overall, 10.4% were MRSA positive. Electronic medical record (EMR) documented antibiotic exposure in the year prior to admission was the best prediction rule, identifying patients accounting for 84% of MRSA while requiring culturing of 51% of patients. Negative- and positive-predictive value was calculated for EMR documentation of antibiotic exposure in our VA hospital population as 0.94 and 0.15 for MRSA. Initial CEA models suggest that MRSA active surveillance culturing is cost-effective under most ranges of MRSA prevalence.

EMR documentation of antibiotic exposure in the year prior to admission identifies most MRSA transmission risk while requiring culturing of only 51% of admitted patients. This approach has the potential for significant cost-savings compared to the current practice of universal active surveillance if validated at other VA hospitals.

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Journal Articles

  1. Schweizer ML, Furuno JP, Harris AD, McGregor JC, Thom KA, Johnson JK, Shardell MD, Perencevich EN. Clinical utility of infection control documentation of prior methicillin-resistant Staphylococcus aureus colonization or infection for optimization of empirical antibiotic therapy. Infection control and hospital epidemiology : the official journal of the Society of Hospital Epidemiologists of America. 2008 Oct 1; 29(10):972-4. [view]
  2. Furuno JP, Hebden JN, Standiford HC, Perencevich EN, Miller RR, Moore AC, Strauss SM, Harris AD. Prevalence of methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii in a long-term acute care facility. American journal of infection control. 2008 Sep 1; 36(7):468-71. [view]
Conference Presentations

  1. Morgan DJ, Bradham DD, Schweizer ML, Furuno JP, Thom KA, Harris AD, Perencevich EN. Patient Perception of Contact Precautions. Poster session presented at: Society for Healthcare Epidemiology of America Scientific Annual Meeting; 2008 Apr 1; Orlando, FL. [view]
  2. Morgan DJ, Furuno JP, Strauss SM, Thom KA, Bradham DD, Schweizer ML, Roghmann M, Harris AD, Perencevich EN. Prediction rules to identify patients at high-risk of multidrug-resistant organism colonization at hospital admission in a population with a high incidence of community-associated Methicillin-resistant Staphylococcus aureus (MRSA). Poster session presented at: Interscience Conference on Antimicrobial Agents and Chemotherapy / Infectious Diseases Society of America Joint Meeting; 2008 Oct 27; Washington, DC. [view]

DRA: Acute and Combat-Related Injury, Health Systems
DRE: Diagnosis, Prevention
Keywords: Acute illness, Screening
MeSH Terms: none

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