
A study conducted in three US nursing homes highlights the challenge of reducing environmental contamination with multidrug-resistant organisms (MDROs).
The study by researchers with the University of California Los Angeles Medical Center and the University of California Irvine School of Medicine, published last week in Infection Control & Hospital Epidemiology, involved implementation of routine bathing/showering with chlorhexidine and nasal iodophor to reduce MDRO colonization in residents. After a 3-month phase-in and 3-month intervention, researchers repeatedly tested for skin colonization with methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, extended-spectrum beta-lactamase producers, and carbapenem-resistant Enterobacterales. They also swabbed high-touch surfaces in the rooms of MDRO carriers.
From the 3-month baseline through the intervention period, overall resident MDRO prevalence fell from 46% (411 of 900 residents) to 29% (262/900), with each individual pathogen seeing significant declines in prevalence. In multivariable models, the intervention was associated with a 55% relative reduction in MDRO prevalence (odds ratio [OR], 0.45; 95% confidence interval [CI], 0.37 to 0.56).
Rooms of colonized residents remain contaminated
However, in the rooms of residents who remained colonized with an MDRO despite the intervention, 87% (288/330) of high-touch objects were still colonized with one or more MDRO, and the intervention was not associated with any MDRO reduction overall (OR, 1.02; 95% CI, 0.81 to 1.27). MDRO fomite contamination in rooms of MDRO carriers was associated with antibiotic use (OR, 1.54; 95% CI, 1.19 to 1.98], wound presence (OR, 1.34; 95% CI, 1.02 to 1.77), and specific fomites such as bedside table/bedrails (OR, 12.7; 95% CI, 9.37 to 17.25).
"Although the exact reason for lack of MDRO environmental contamination reduction in rooms of residents with MDRO colonization during the decolonization period is difficult to determine, our result may suggest that those residents who failed MDRO decolonization may be more likely to shed their MDRO in the environment," the study authors wrote.
The authors added that the findings indicate environmental surfaces in the rooms of MDRO carriers may require special attention for environmental decontamination.