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Association Between Contact Precautions and Transmission of Methicillin-Resistant Staphylococcus aureus in Veterans
Karim Khader1,2, Alun Thomas2, Vanessa Stevens1,2
1IDEAS Center of Innovation, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah.
Importance:
The effectiveness and importance of contact precautions for endemic pathogens has long been debated, and their use has broad implications for infection control of other pathogens.
Objective:
To estimate the association between contact precautions and transmission of methicillin-resistant Staphylococcus aureus (MRSA) across US Department of Veterans Affairs (VA) hospitals.
Design, Setting, And Participants:
This retrospective cohort study used mathematical models applied to data from a population-based sample of adults hospitalized in 108 VA acute care hospitals for at least 24 hours from January 1, 2008, to December 31, 2017. Data were analyzed from May 2, 2019, to December 11, 2020.
Exposures:
A positive MRSA test result, presumed to indicate contact precautions use according to the VA MRSA Prevention Initiative.
Main Outcomes And Measures:
The main outcome was the association between contact precautions and MRSA transmission, defined as the relative transmissibility attributed to contact precautions. A contact precaution effect estimate (<1 indicates a reduction in transmission associated with contact precautions) was estimated for each hospital and then pooled over time and across hospitals using meta-regression.
Results:
In this cohort study of 108 VA hospitals, more than 2 million unique individuals had over 5.6 million admissions, of which 14.1% were presumed to have contact precautions with more than 8.4 million MRSA surveillance tests. Pooled estimates found associations between contact precautions and transmission to be stable from 2008 to 2017, with estimated transmission reductions ranging from 43% (95% credible interval [CrI], 38%-48%) to 51% (95% CrI, 46%-55%). Over the entire 10-year study period, contact precautions reduced transmission 47% (95% CrI, 45%-49%), and the intrafacility autocorrelation coefficient estimate was 0.99, suggesting consistent estimates over time within facilities. Larger facilities and those with higher admission screening compliance observed additional reductions in transmission associated with contact precautions (relative rate, 0.84; 95% CI, 0.74-0.96 and 0.74; 95% CI, 0.58-0.96, respectively) compared with smaller facilities and those with lower admission screening compliance. Facilities in the southern US had a smaller transmission reduction attributable to contact precautions (relative rate, 1.14; 95% CI, 1.01-1.28) compared with facilities in other regions in the US.
Conclusions And Relevance:
In this cohort study of adults in VA hospitals, transmissibility of MRSA was found to be reduced by approximately 50% among patients with contact precautions. These results provide an explanation for decreasing acquisition rates in VA hospitals since the MRSA Prevention Initiative.
Insights
Contact precautions significantly reduced methicillin-resistant Staphylococcus aureus (MRSA) transmission by approximately 50% in VA hospitals. This finding supports the effectiveness of MRSA Prevention Initiative strategies in reducing hospital-acquired infections.
Area of Science:
- Infectious Diseases
- Epidemiology
- Healthcare Management
Background:
- The effectiveness of contact precautions for endemic pathogens remains a subject of debate, impacting broader infection control strategies.
- Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant challenge in healthcare settings, necessitating robust infection control measures.
Purpose of the Study:
- To quantify the association between contact precautions and the transmission of MRSA within US Department of Veterans Affairs (VA) hospitals.
- To evaluate the impact of the VA MRSA Prevention Initiative on MRSA transmission rates over a 10-year period.
Main Methods:
- A retrospective cohort study analyzing data from 108 VA acute care hospitals between 2008 and 2017.
- Mathematical models and meta-regression were employed to estimate the pooled effect of contact precautions on MRSA transmission, adjusting for facility-level factors.
Main Results:
- Contact precautions were associated with a stable and significant reduction in MRSA transmission, estimated at 47% (95% credible interval [CrI], 45%-49%) over the study period.
- Larger facilities and those with higher screening compliance showed greater reductions in MRSA transmission.
- Facilities in the southern US exhibited a smaller reduction in transmission compared to other regions.
Conclusions:
- Contact precautions are effective in reducing MRSA transmission by approximately 50% in VA hospitals.
- The findings provide evidence supporting the success of the MRSA Prevention Initiative in decreasing acquisition rates.
- Implementation strategies for contact precautions may need to consider facility size, screening compliance, and regional variations.
