Predictors of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci co-colonization among nursing facility patients.

BACKGROUND: The emergence of vancomycin-resistant Staphylococcus aureus (VRSA) poses significant challenges for antibiotic therapy. We characterized the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) co-colonization that may facilitate resistance transfer and vancomycin-resistant S aureus emergence among nursing facility patients.

METHODS: We cultured newly admitted patient hands, nares, oropharynx, groin, and perianal region plus wounds and device insertion sites, if applicable, upon enrollment at day 14, day 30, and monthly follow-up up to 6 months. Demographic, comorbidity, and antimicrobial use data were collected. Functional status was assessed at each visit using the Physical Self-Maintenance Scale. Multinomial logistic regression was performed to determine factors predictive of co-colonization.

RESULTS: Five hundred eight patients were enrolled, with an average follow-up time of 28.5days. Prevalence of MRSA/VRE co-colonization, MRSA alone, and VRE alone was 8.7%, 8.9%, and 23.4%, respectively. Independent predictors of co-colonization included indwelling device use (odds ratio [OR] = 5.5 [2.2-13.7]), recent antibiotic use (OR = 2.5 [1.4-4.2]), diabetes (OR = 1.9 [1.0-3.8]), and the presence of open wounds (OR = 1.9 [1.0-3.6]).

CONCLUSIONS: High rates of VRE are driving co-colonization with MRSA in nursing facilities. Indwelling device use, recent antibiotic use, diabetes, and open wounds predicted patient co-colonization.