Characteristics of nursing homes with high rates of invasive methicillin-resistant Staphylococcus aureus infections.

Abstract

Background: Nursing home residents experience a large burden of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections. Data are limited regarding nursing home characteristics associated with differences in facility-level invasive MRSA rates.

Methods: We analyzed 2011-2015 data from CDC's Emerging Infections Program (EIP) active population- and laboratory-based surveillance for invasive MRSA cases within seven states. A nursing home-onset case was defined as MRSA cultured from a normally sterile site in a person living in a nursing home 3 days before culture collection. Facility rates were calculated as nursing home-onset cases per 100,000 resident-days. Nursing home resident-day denominators and facility characteristics were obtained from four Centers for Medicare & Medicaid Services (CMS) datasets. A general estimating equations model with a logit link assessed characteristics of the facilities with highest rates comprising 50% of nursing home MRSA cases ("high rates").

Results: The 626 nursing homes in the surveillance area had 2824 invasive MRSA cases; 82% of facilities had at ≥1 case. The 20% of facilities with highest rates (≥3.84 cases/100,000 resident-days) had 50% of nursing home-onset cases. In multivariable regression, facilities with high rates were more likely to have CMS-derived characteristics of presence of a resident with a multidrug-resistant organism; or greater proportions of residents who were male, were short stay (in the facility <100 days), had a nasogastric or percutaneous gastrostomy tube, or require extensive assistance with bed repositioning; and more likely to be in an EIP area with higher hospital-onset MRSA rates. Higher registered nurses staffing levels (hours/resident/day) and higher proportions of White residents were associated with lower rates.

Conclusions: Facilities with higher invasive MRSA rates served residents with more clinical and functional care needs. Increasing registered nurse staffing in high-risk facilities might assist with reduction of invasive MRSA rates. These findings could help prioritize nursing homes for future MRSA prevention work.