Decolonization strategy cut infection-related hospitalizations in nursing homes, trial finds

Elderly woman in wheelchair

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The results of a randomized trial indicate a universal decolonization strategy could cut infection-related hospitalization in nursing home residents.

The study, published yesterday in the New England Journal of Medicine, found that nursing homes that used a bathing routine to decolonize the skin and nasal passages of nursing home residents saw a significant reduction in infection-related hospitalization and all-cause hospitalization compared with nursing homes that didn't implement the strategy. The decolonization strategy also reduced the prevalence of multidrug-resistant organisms (MDROs), such as methicillin-resistant Staphylococcus aureus (MRSA).

The study authors say the strategy, which has been adopted in many hospitals to reduce bacterial infections in intensive care unit (ICU) and other at-risk patients, could help protect a population that is highly vulnerable to infections because of age and illness. Roughly three million healthcare-associated infections (HAIs), including urinary tract and bloodstream infections, occur in nursing homes every year, resulting in 150,000 hospital admissions and 350,000 deaths annually. MDRO prevalence in nursing homes is four times higher than in hospitals.

Nimalie Stone, MD, MS, a senior advisor for long-term care with the Center for Disease Control and Prevention's Division of Healthcare Quality Promotion and a technical advisory panel member for the trial, says the strategy is important not just for preventing drug-resistant infections in nursing home residents, but could also help protect them from the physical and emotional toll that hospitalization can take.

"Nursing homes are a critical part of our healthcare system," Stone told CIDRAP News. "I think it's incredibly exciting to have an infection prevention intervention that is actually making residents safer."

Routine antiseptic bathing and nasal swabs

The strategy was tested in the cluster-randomized Protect Trial, conducted in 28 nursing homes in California by a team led by researchers from Harbor-UCLA Medical Center and the University of California Irvine School of Medicine. The 14 homes that were randomized to the decolonization group adopted a bathing and showering routine with chlorhexidine gluconate (CHG) soap. They also swabbed residents' nasal passages with nasal iodophor antiseptic twice daily for 5 days a week, every other week. The 14 nursing homes in the control group followed their standard bathing routines.

To evaluate the effectiveness of the decolonization strategy, trial investigators compared hospitalization due to infection during an 18-month baseline period (September 2015 to February 2017) and an 18-month intervention period (July 2017 to December 2018). The secondary outcome was all-cause transfer to hospital. They also looked at the prevalence of MDRO carriage among residents during the two periods.

A total of 28,956 nursing home residents were involved in the study—15,004 during baseline and 13,952 during the intervention period. The characteristics of the residents in the control and decolonization nursing homes were similar. In the decolonization nursing homes, the mean compliance with the CHG bathing routine and nasal iodophor application was 87% and 67%, respectively, during the intervention period.

During the baseline period, the proportion of hospital transfers due to infection was 62.2% in the control nursing homes and 62.9% in the decolonization nursing homes. During the intervention period, the percentage of hospital transfers due to infection fell to 52.2% in the decolonization nursing homes (risk ratio [RR], 0.83; 95% confidence interval [CI], 0.79 to 0.88), while remaining roughly the same (62.6%) in the control nursing homes [RR, 1.00; 95% CI, 0.96 to 1.04] The relative risk reduction in the decolonization nursing homes versus controls was 16.6%.

I think it's incredibly exciting to have an infection prevention intervention that is actually making residents safer.

Results were similar with regards to all-cause hospitalization. In the decolonization group, the proportion of all-cause hospitalization fell from 35.5% in the baseline period to 32.4% during the intervention (RR, 0.92; 95% CI, 0.88 to 0.96). In the control group, all-cause hospitalization rose from 36.6% during baseline to 39.2% during the intervention (RR, 1.08; 95% CI, 1.04 to 1.12). The relative risk reduction versus controls was 14.6%.

A microbiologic analysis of swab samples collected from residents of 24 nursing homes in the trial found that MDRO colonization prevalence fell from 48.9% in the decolonization group to 32% by the end of the intervention, while MDRO prevalence in control nursing homes fell only slightly (48.3% to 47.2%). The prevalence of any MDRO significantly declined in decolonization versus control nursing homes (RR, 0.70; 95% CI, 0.58 to 0.84), with reductions in MRSA (RR, 0.73; 95% CI, 0.59 to 0.92), vancomycin-resistant Enterococci (RR, 0.29; 95% CI 0.14 to 0.62), and extended-spectrum beta-lactamase–producing bacteria (RR, 0.50; 95% CI, 0.34 to 0.75).

Stone said the 30% reduction in MDRO colonization is significant because of the high prevalence of MDROs found in nursing homes in this study and others—as high as 55% to 60% in some studies. Previous research has shown that colonization with resistant organisms like MRSA can increase the risk of infection.

"That's a pretty big impact, given the level of exposure [to MDROs] in this population," she said.

The number needed to treat in order to prevent one infection-related hospitalization and one all-cause hospitalization was 10 and 12 residents, respectively. The researchers estimate that the decolonization strategy, if applied to all residents in a 100-bed nursing home, could prevent two infection-related hospitalizations per month.

"Compared with other healthcare strategies, this is a relatively simple win for nursing homes, and we hope nursing homes will want to adopt it," senior investigator, Susan Huang, MD, MPH, of the University of California Irvine School of Medicine, said in a press release from the Agency for Healthcare Research and Quality, which funded the study.

Transmission networks

But the findings could have impacts beyond nursing homes as well, according to Stone.

That's because nursing homes are now commonly serving as a "bridge" for patients coming from hospitals and long-term acute care facilities (LTACs), where they've had to exposure to antibiotics, in-dwelling devices (such as catheters), and other risk factors for MDRO colonization and infection. The constant movement of patients between these facilities creates networks of transmission that can increase the risk of drug-resistant infections in all of them.

"People move in and out of these different healthcare settings constantly, and those pathogens go with them," she said.

The strategy of decolonizing patients with CHG and a nasal antiseptic has been shown in other trials to reduce MDRO colonization and infection in intensive care unit (ICU), non-ICU patients with devices, and MRSA carriers follow hospital discharge. Stone says that if regional networks of nursing homes, acute care hospitals, and LTACs all used the decolonization strategy, you could see benefits in each of those environments.

"Decolonizing individuals across healthcare can really benefit the entire community," she said.

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