Universal decolonization using topical antiseptics is shown to reduce hospitalizations due to methicillin-resistant Staphylococcus aureus (MRSA) infection among elderly home residents in Hong Kong.
A decolonization programme for MRSA and carbapenem-resistant Acinetobacter (CRA) was rolled out in 330 residential care homes for the elderly (RCHEs) housing 20,741 residents in catchment areas of three major hospital networks in Hong Kong. Among these invited RCHEs, 257 institutions housing 16,190 residents continued with the programme. [Public Health Pract (Oxf) 2026;11:100706]
The RCHE residents were instructed to apply 10 percent povidone-iodine (PVP-I) nasal ointment to their nostrils (initially BID QW; switched to QD, Monday to Friday, every alternate week since March 2023), and use 2 percent chlorhexidine gluconate (CHG) bath solution for showers and hair washing on alternate days. Group 1 participants underwent decolonization both in the RCHEs and during hospitalization, while group 2 underwent decolonization in the RCHEs only. The control group involved residents of noninvited RCHEs who were admitted to network hospitals.
The incidence of MRSA and CRA infections, bacteraemia, and associated death during the intervention period in 2023 was compared with rates during the baseline period in 2017–2019 across group 1, group 2 and the control group.
Decolonization effective
Hospitalization due to community-onset MRSA infection was significantly reduced, by 12.2 percent (p=0.035), in group 1 during the intervention period compared with the baseline period. Reductions observed for group 2 (13.3 percent; p=0.068) and the control group (5.9 percent; p=0.070) were not statistically significant.
MRSA bacteraemia showed larger but nonsignificant reductions in group 1 (28.1 percent; p=0.158) and group 2 (27.9 percent; p=0.207) than in the control group (21.5 percent; p=0.036).
Reduction in MRSA-associated mortality was larger in group 1 (51.1 percent; p=0.096) than in group 2 (18.7 percent; p=0.641) or the control group (22.2 percent; p=0.208), but was nonsignificant across all groups.
“The magnitude of reduction was consistently greater in group 1 than in the control group for all three outcomes, supporting the genuine effect of decolonization for MRSA rather than any confounding effect observed in the control group,” the researchers commented. “The observed effect was unlikely due to variation of infection control practices.”
A significant increase in CRA infection was observed in group 1, while a significant decrease was found in the control group. No significant difference was found for CRA bacteraemia or death.
Fairly good compliance
“To our knowledge, this is the largest study … using a quasi-experimental design, to investigate the effectiveness of decolonization of MRSA and CRA in elderly homes, showing fairly good compliance,” the researchers reported.
Mean utilization rates of PVP-I ointment were 79.4–96.2 percent among participating RCHEs, while utilization rates of CHG bath solution were 79.9–97.2 percent.
Iodine strip testing to confirm application of the ointment to residents’ nostrils showed positive rates of 74.0–75.5 percent.
Implications
“Decolonization could potentially help tackle S. aureus, the top pathogen causing the largest number of deaths attributable to antimicrobial resistance among adults,” the researchers suggested. [Lancet 2024;404:1199-1226] “Further consideration of feasibility, staff compliance, residents’ acceptance and resource implications is required before full implementation in real-world settings.”