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.