Estimating Changes in Facility Methicillin-Resistant Staphylococcus aureus (MRSA) Infection Rates Due to Changes in...

Area of Science:

• Infection Prevention and Control
• Healthcare Epidemiology
• Antimicrobial Resistance

Background:

• The effectiveness of contact precautions (CP) and active surveillance (AS) for preventing methicillin-resistant Staphylococcus aureus (MRSA) in acute care settings is uncertain.
• Some studies indicate CP reduces MRSA spread, while others show limited benefit.
• The COVID-19 pandemic disrupted standard MRSA prevention practices, offering a unique opportunity to evaluate their impact on MRSA healthcare-associated infections (HAIs).

Purpose of the Study:

• To assess the impact of changes in MRSA prevention practices (AS, CP for colonized, CP for infected) on MRSA HAIs during the COVID-19 pandemic.
• To evaluate the association between the discontinuation and reinstatement of these practices and MRSA HAI rates in Veterans Affairs (VA) acute care hospitals.

Main Methods:

• A study of 121 VA acute care hospitals from July 2020 to June 2022.
• Facility practices were assessed via national surveys, and patient-level data identified MRSA HAIs.
• Statistical models (Poisson, negative binomial, mixed-effects Poisson regression) were used to estimate associations, adjusting for baseline MRSA burden and other factors.

Main Results:

• Among 905,164 admissions, 1,708 incident MRSA HAIs were identified.
• Many facilities temporarily suspended prevention practices but later reinstated them.
• While simpler models suggested higher MRSA rates upon discontinuation, these associations were not significant in adjusted mixed-effects models.

Conclusions:

• Discontinuation of MRSA prevention practices during the pandemic was not consistently associated with increased HAIs when baseline burden was considered.
• Findings highlight the importance of facility-specific factors and modeling assumptions in infection control evaluations.
• Unmeasured pandemic-related practices likely influenced transmission, emphasizing the need for flexible, evidence-based infection prevention policies.