Only decolonizing residents reduced the drug-resistant bacteria they carried on their skin, and adding daily enhanced cleaning produced no measurable additional benefit, according to a study of two Southern California nursing homes published August 5 in JAMA Network Open.
The comparison matters because infection control budgets in long-term care are finite. Facilities are frequently asked to do both, and this study suggests that when only one is affordable, the choice is not a coin flip.
For families with a relative in a nursing home, the finding translates into a question worth asking at the next care conference. Multidrug-resistant organisms are endemic in these settings, with studies showing more than half of residents carry them on their skin, and carriage precedes infection. What a facility does about that is a legitimate thing for a family to inquire about.
The Four-Phase Design and the Main Findings
Researchers at the University of California Irvine School of Medicine ran a four-phase quality-improvement study at two nursing homes, using data collected between March 2019 and April 2021. The phases were implemented in sequence: universal decolonization alone, routine care as the control, once-daily enhanced cleaning alone, and decolonization combined with enhanced cleaning.
The measured outcomes were carriage of multidrug-resistant organisms on resident skin and in nostrils, and contamination of high-touch objects in bedrooms and common areas.
In adjusted models, decolonization alone was associated with a 59 percent reduction in carriage compared with the control phase and a 64 percent reduction compared with enhanced cleaning, CIDRAP reported in its summary of the findings. Enhanced cleaning alone did not reduce carriage, and it added no benefit when combined with decolonization.
Decolonization in practice meant chlorhexidine used for routine bathing and showering, paired with a nasal iodophor such as povidone-iodine on a defined schedule. It is a resident-level intervention rather than an environmental one, which is precisely why the result is informative.
Shared Spaces Told a Different Story
Bedroom contamination followed the same pattern as skin carriage. Decolonization alone reduced it by 84 percent compared with control and by 74 percent compared with enhanced cleaning, while enhanced cleaning alone produced no reduction and added nothing to decolonization.
Common areas broke the pattern. There, the combined intervention reduced contamination better than either approach alone.
The logic is intuitive once stated. If bacteria on surfaces originate primarily from the people who touch them, reducing what residents carry reduces what ends up on the bed rail. Common areas gather traffic from many residents and staff over a day, and surface disinfection reaches contamination that resident-level treatment cannot.
The authors framed the practical implication in resource terms. Writing in JAMA Network Open, they noted that implementing multiple strategies is expensive and resource intensive, and that "it is necessary to prioritize the most effective strategies." Their conclusion was that resource-constrained settings should prioritize decolonization alongside targeted disinfection in shared spaces after activities.
Families Choosing or Monitoring a Facility
Nothing here is a diagnosis or a treatment instruction, and no family should attempt decolonization on their own. Chlorhexidine and nasal antiseptics used in these protocols are administered under a facility program with clinical oversight, and improvising carries risks including skin reactions and allergic responses.
What a family can do is ask. Reasonable questions at a care conference include whether the facility uses chlorhexidine bathing, whether it has a nasal decolonization protocol, how it handles residents returning from hospital stays, and how it monitors infection rates. Facilities with active programs generally answer readily.
The stakes are concrete for people with the highest exposure to health care. Residents who move between hospital and nursing home, those with indwelling devices such as urinary catheters or feeding tubes, people with open wounds or pressure injuries, and those who have received multiple courses of antibiotics carry the greatest risk of both colonization and subsequent infection.
Older adults bear a disproportionate share of the burden from resistant infections generally. When a resistant organism causes an infection, treatment options narrow, hospital stays lengthen, and outcomes worsen. Prevention at the carriage stage is the intervention that happens before any of that.
There is a household dimension as well. Residents who return home for weekends or who are discharged to family care can carry these organisms with them, and the standard advice for relatives is unglamorous but effective: hand hygiene before and after contact, careful wound care under a clinician's direction, and telling any new provider about a known colonization history so treatment decisions account for it.
Limits of a Two-Facility Study
The design constraints deserve to be stated clearly rather than buried. This was a quality-improvement study at two facilities, not a randomized controlled trial across many sites, as McKnight's Long-Term Care News noted in its account of the design.
Phases were implemented sequentially over roughly two years, which means anything else that changed over that period, including staffing, resident turnover, seasonal factors, and pandemic-era infection control practices, could contribute to the differences observed. Two Southern California nursing homes may not represent facilities elsewhere with different staffing ratios, resident populations, or baseline practices.
The study also measured carriage and contamination rather than infections, hospitalizations, or deaths. Those are reasonable surrogate outcomes because carriage precedes infection, but they are not the same thing.
Importantly, this work builds on a stronger evidence base rather than standing alone. A large cluster-randomized trial in nursing homes previously found that universal decolonization reduced infection-related hospital transfers, with MDRO carriage prevalence falling from about 49 percent to 32 percent in the decolonization group while remaining near 47 percent under routine care. The new study addresses a narrower question about how decolonization compares with enhanced cleaning when resources force a choice.
An accompanying JAMA Network Open commentary framed the work as an argument for hypothesis-driven research in nursing home infection prevention rather than as settled guidance. Current infection control guidance has not changed on the basis of this study, and larger multi-site work would be needed to establish how broadly the comparison holds. For facility administrators weighing where to spend a limited infection prevention budget, the finding offers a data point that was previously missing.
Key Questions Answered
What did the study find? Universal decolonization of residents was associated with a 59 percent reduction in multidrug-resistant organism carriage compared with routine care. Enhanced daily cleaning alone reduced nothing and added no benefit when combined with decolonization.
What is decolonization? Chlorhexidine used for routine bathing and showering, paired with a nasal iodophor such as povidone-iodine on a set schedule, applied to all residents rather than only those known to be colonized.
Did cleaning help at all? In common areas, combining cleaning with decolonization reduced contamination better than either approach alone. For resident skin and bedrooms, cleaning added nothing.
How strong is the evidence? This was a four-phase quality-improvement study at two facilities, not a randomized trial. It measured carriage and surface contamination rather than infections or deaths.
Should families try this at home? No. These are facility-level protocols with clinical oversight. Do not attempt decolonization independently.
What can a family actually do? Ask whether the facility uses chlorhexidine bathing, whether it has a nasal decolonization protocol, how it handles residents returning from hospitals, and how it tracks infection rates.
Which residents face the highest risk? Those moving between hospital and nursing home, people with catheters or feeding tubes, residents with wounds or pressure injuries, and those who have had multiple antibiotic courses.
