A routine disinfection procedure commonly used when admitting patients to intensive care units (ICU) can increase ‘superbug’ infections according to new research from the University of Aberdeen.
The study compared bloodstream infections in ICU patients who experienced different types of disinfection when admitted.
The results showed that the ‘universal disinfection’ of all patients admitted to ICU was linked to the rise of superbug – ‘methicillin-resistant Staphylococcus epidermidis’ (MRSE) bloodstream infections in vulnerable patients.
The results are published today, June 11, 2025, in Lancet Microbe.
Universal decolonisation refers to the disinfection of all patients admitted to ICUs and was introduced during the MRSA epidemic in the 1990’s to attempt to control healthcare-associated infections. However, hospital infections and how they respond to antibiotics are known to change over time. This is why the team, led by Professor Karolin Hijazi, sought to re-evaluate the benefits and unintended harms of these infection control practices, particularly for those disinfectants implicated in rise of antimicrobial resistance.
During universal decolonisation, when patients are admitted to ICU their whole body is disinfected with an antimicrobial called chlorhexidine - a disinfectant also widely used to disinfect medical devices and hospital surfaces. Patients also receive nasal treatment with another disinfectant called mupirocin.
Currently, there is inconsistency in disinfection practices across hospitals in the UK with some hospitals adopting the universal decolonisation of all patients, whilst others employ a more targeted and risk-based approach of decolonisation of only those patients who have tested positive for MRSA. This means that much larger volumes of the disinfectants chlorhexidine and mupirocin are used in hospitals that practice universal decolonisation.
The team compared the bloodstream infection type and resistance rates of patients over 13 years across two intensive care units in Scotland practicing the different decolonisation approaches and found that universal decolonisation practices were related to increased MRSE infections compared to a targeted approach.
Professor Hijazi Chair in Oral & Maxillofacial Medicine at the University of Aberdeen, who led the study explains their findings: “We found that the drastic reduction of disinfectant when using targeted decolonisation of only MRSA-positive patients reduced bloodstream infections related to MRSE. Whilst MRSE is generally not life-threatening, this data is a concern as MRSE increases the burden of circulating antimicrobial resistance.
“However, reducing disinfectant did not increase all bloodstream infections from serious pathogens. This means that universal decolonisation is not superior to more sparing and targeted approaches in controlling serious bloodstream infections.
“This research essentially demonstrates that the excess use of disinfectants in universal decolonisation offered no advantage in terms of control of serious blood infections in a low MRSA ICU setting but instead caused the unintended rise of MRSE bloodstream infections.
“Universal decolonisation is associated with greater risks of antimicrobial resistance and costs at no increased benefit. “According to the findings of our study, in low MRSA settings universal decolonisation is likely an unnecessary and harmful practice.”
The authors suggest that hospitals should consider the unintended harms of universal decolonisation, particularly in the context of global rise of antimicrobial resistance.
Professor Hijazi adds: “As the landscape of hospital infections changes over time, it is imperative to re-evaluate the benefits and unintended harms of all antimicrobial treatments including disinfection practices. This is particularly important for disinfectants implicated in antimicrobial resistance.
“Our research aligns with the top 10 research priorities of the ‘five-year action plan for antimicrobial resistance’ set out by the UK government, agencies and administrations in Scotland, Wales and Northern Ireland UK, which called to strengthen the evidence of the role of biocides in driving antimicrobial resistance.
“Our study fits squarely with this commitment and should inform standardised national guidelines for effective and safe patient decolonisation in low MRSA settings.
“Skin decolonisation must effectively control hospital infections whilst minimising emergence and spread of antimicrobial resistance which is ‘the silent pandemic’ of our times.
“Skin decolonisation of hospital patients is also very costly as it must be prescribed by specialist medical staff and administered by trained nurses. So we anticipate significant cost savings associated with efforts to reduce and avoid this practice where not necessary.”
Professor Marco Oggioni from the University of Bologna who contributed to the research added: “Antimicrobial stewardship and other measures for infection prevention are our most powerful tools to contrast the global emergency of antimicrobial drug resistance, but this should never hinder our critical re-evaluation of the instruments we utilise to achieve our goals.”
Professor Ian Gould, Honorary Professor at the University of Aberdeen concluded: "This timely study is the culmination of 25 years' work in Aberdeen Royal Infirmary.
“The original study was borne out of an initial response to control a nationwide epidemic of MRSA, the original superbug, by using universal decolonization.
“We have subsequently learned to use antibiotics cautiously but this important study provides the firmest evidence yet that antiseptics and disinfectants, which are also commonly misused, should be subject to the same restrictions.”
This study was funded by NHS Grampian Charity, and was a collaboration with Dundee University, Ninewells Hospital, Leicester University and the University of Bologna.