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Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
Methicillin-resistant Staphylococcus aureus Colonization and Pre- and Post-hospital Discharge Infection Risk
Richard E Nelson1,2, Martin E Evans3,4,5, Loretta Simbartl3
1IDEAS Center, Veterans Affairs Salt Lake City Health Care System.
Background:
The Department of Veterans Affairs implemented an active surveillance program for methicillin-resistant Staphylococcus aureus (MRSA) in 2007 in which acute care inpatients are tested for MRSA carriage on admission, unit-to-unit transfer, and discharge. Using these data, we followed patients longitudinally to estimate the difference in infection rates for those who were not colonized, those who were colonized on admission (importers), and those who acquired MRSA during their stay. We examined MRSA infections that occurred prior to discharge and at 30, 90, 180, and 365 days after discharge.
Methods:
We constructed a dataset of 985626 first admissions from January 2008 through December 2015 who had surveillance tests performed for MRSA carriage. We performed multivariable Cox proportional hazards and logistic regression models to examine the relationship between MRSA colonization status and infection.
Results:
The MRSA infection rate across the predischarge and 180-day postdischarge time period was 5.5% in importers and 7.0% in acquirers without a direct admission to the intensive care unit (ICU) and 11.4% in importers and 11.7% in acquirers who were admitted directly to the ICU. The predischarge hazard ratio for MRSA infection was 29.6 (95% confidence interval [CI], 26.5-32.9) for importers and 28.8 (95% CI, 23.5-35.3) for acquirers compared to those not colonized. Fully 63.9% of all MRSA pre- and postdischarge infections among importers and 61.2% among acquirers occurred within 180 days after discharge.
Conclusions:
MRSA colonization significantly increases the risk of subsequent MRSA infection. In addition, a substantial proportion of MRSA infections occur after discharge from the hospital.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) colonization significantly raises infection risk. Many MRSA infections occur after hospital discharge, highlighting the need for continued surveillance and prevention strategies.
Area of Science:
- Infectious Diseases
- Healthcare Epidemiology
- Public Health Surveillance
Background:
- The Department of Veterans Affairs initiated an active surveillance program for methicillin-resistant Staphylococcus aureus (MRSA) in 2007.
- This program involves testing acute care inpatients for MRSA carriage upon admission, transfer, and discharge.
- Patient data are used to longitudinally track MRSA infection rates based on colonization status.
Purpose of the Study:
- To estimate the difference in MRSA infection rates among patients based on their colonization status: not colonized, colonized on admission (importers), or acquired MRSA during hospitalization (acquirers).
- To examine MRSA infections occurring before discharge and at multiple time points up to 365 days post-discharge.
Main Methods:
- A dataset of 985,626 first admissions from January 2008 to December 2015 with MRSA carriage surveillance tests was analyzed.
- Multivariable Cox proportional hazards and logistic regression models were employed to assess the association between MRSA colonization status and infection risk.
- Infection rates and hazard ratios were calculated for different patient groups and time periods.
Main Results:
- MRSA infection rates were elevated in both importers and acquirers compared to non-colonized patients, particularly in those admitted directly to the ICU.
- The predischarge hazard ratio for MRSA infection was substantially higher for importers (29.6) and acquirers (28.8) versus non-colonized individuals.
- A significant proportion of MRSA infections (63.9% for importers, 61.2% for acquirers) occurred within 180 days after hospital discharge.
Conclusions:
- MRSA colonization is a significant risk factor for subsequent MRSA infections.
- A considerable number of MRSA infections manifest after patients have been discharged from the hospital.
- Findings underscore the importance of ongoing surveillance and infection control measures beyond the inpatient setting.
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