An international study has, for the first time, revealed a strong and direct link between the rise of antibiotic-resistant bacteria and universal disinfection procedures applied to patients in intensive care units. Published in The Lancet Microbe , the study calls for a reassessment of healthcare guidelines on the widespread use of disinfectants.
"Our research highlights the unintended consequences of universal decolonization in a global context where antibiotic resistance is an increasing threat," says Marco Oggioni, professor at the Department of Pharmacy and Biotechnology at the University of Bologna and one of the study's authors. "Coordinated efforts to prevent antibiotic-resistant infections are crucial, but they must not prevent us from critically re-evaluating the tools we use to achieve these goals."
Universal decolonization is a preventive procedure applied to patients upon admission to intensive care. The entire body is disinfected with chlorhexidine—a commonly used antiseptic also employed to sanitize medical devices and hospital surfaces - and an additional nasal treatment is administered with another disinfectant, mupirocin.
Introduced in the 1990s, the procedure has proven effective in curbing the spread of MRSA (Methicillin-Resistant Staphylococcus aureus), a bacterium resistant to certain antibiotics that can cause severe infections.
For several years, the use of universal decolonization reduced MRSA infection rates from 30–40% to below 5% in many countries, including Scotland, where this study was conducted. The situation is different in Italy, where data from the Istituto Superiore di Sanità still indicate a 26% MRSA prevalence.
"Currently, UK healthcare facilities take different approaches: some hospitals apply universal decolonization to all patients, while others take a more targeted approach, decolonizing only those who test positive for MRSA," Oggioni explains. "As a result, hospitals adopting universal decolonization use significantly larger volumes of disinfectants such as chlorhexidine and mupirocin."
Focusing on two Scottish hospitals using these different approaches, the researchers compared bacterial infection levels and antibiotic resistance rates among intensive care patients over a 13-year period.
The results showed higher rates of infection caused by the superbug MRSE (Methicillin-Resistant Staphylococcus epidermidis) in the hospital practicing universal decolonization. MRSE is less well-known than MRSA but is increasingly common and resistant to several types of antibiotics.
"Our findings show that the excessive use of disinfectants in universal decolonization may not improve infection control, and instead leads to a rise in MRSE infections," confirms Professor Hijazi, who coordinated the study. "In intensive care settings where the risk of MRSA infection is low, indiscriminate use of decolonization procedures may not only be ineffective but also potentially harmful."
"This applies to regions where MRSA prevalence is low, like Scotland," Oggioni adds. "In Italy, however, MRSA infection risk remains high despite a downward trend, which means both targeted and universal decolonization are still necessary. We'll need to reduce MRSA prevalence in Italy before we can reassess the risks and benefits of these intervention procedures."
The study's authors therefore call for a reassessment of current practices in light of the evolving epidemiological landscape. New standardized guidelines are needed to identify the most effective decolonization treatments, weighing both the benefits in infection control and the potential impact on antibiotic resistance.
