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Viscosity is an important factor of resistance to alcohol-based disinfectants by pathogens present in mucus
Ryohei Hirose1,2, Takaaki Nakaya3, Yuji Naito1
1Department of Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Abstract:
Alcohol-based disinfectants play an important role in the prevention of healthcare-acquired infection (HAI). We investigated whether pathogens present in mucus acquire resistance to alcohol-based disinfectants, and elucidated the underlying mechanism. Both the resistance of influenza A virus and Escherichia coli to alcohol-based disinfectants or ultraviolet irradiation and the diffusion rate of ethanol were determined in artificial mucus or sputum samples obtained from 27 individuals with acute upper respiratory infection. Pathogens in mucus (artificial mucus or sputum samples) were not completely inactivated by alcohol-based disinfectants (survival rate >10%), suggesting that the alcohol-based disinfectants were ineffective. Pathogen survival and mucus viscosity were strongly correlated (correlation coefficient >0.7, P < 0.001). Additionally, the ethanol diffusion rate decreased with increasing mucus viscosity, which contributed to ethanol resistance. Pronase treatment of sputum samples significantly decreased sputum viscosity and increased the disinfectant effect (P < 0.001 for all). In contrast, complete inactivation was achieved by ultraviolet irradiation independently of mucus viscosity. Thus, mucus viscosity contributes to resistance of pathogens to alcohol-based disinfectants by decreasing the alcohol diffusion rate. These findings can provide a basis for developing new strategies, including improved disinfectants, for overcoming HAI.
Insights
Mucus viscosity hinders alcohol disinfectants, allowing pathogens to survive. This study reveals mucus thickness reduces disinfectant effectiveness, impacting healthcare-acquired infection prevention.
Area of Science:
- Microbiology
- Infectious Diseases
- Biochemistry
Background:
- Alcohol-based disinfectants are crucial for preventing healthcare-acquired infections (HAIs).
- The efficacy of these disinfectants can be influenced by environmental factors, such as the presence of biological materials like mucus.
- Understanding pathogen resistance mechanisms is vital for effective infection control.
Purpose of the Study:
- To investigate if pathogens in mucus develop resistance to alcohol-based disinfectants.
- To elucidate the mechanism behind this potential resistance.
- To compare the efficacy of alcohol-based disinfectants and ultraviolet irradiation in the presence of mucus.
Main Methods:
- Collected artificial mucus and sputum samples from 27 individuals with acute upper respiratory infections.
- Assessed the survival rates of influenza A virus and Escherichia coli after exposure to alcohol-based disinfectants and ultraviolet irradiation.
- Measured ethanol diffusion rates in mucus samples of varying viscosities.
- Utilized pronase treatment to assess the impact of mucus viscosity on disinfectant efficacy.
Main Results:
- Pathogens in mucus samples showed significant survival (>10%) against alcohol-based disinfectants, indicating reduced efficacy.
- A strong positive correlation was found between pathogen survival and mucus viscosity (correlation coefficient >0.7, P < 0.001).
- Increased mucus viscosity directly decreased ethanol diffusion rates, contributing to disinfectant resistance. Pronase treatment reduced viscosity and enhanced disinfectant effects.
- Ultraviolet irradiation achieved complete pathogen inactivation, irrespective of mucus viscosity.
Conclusions:
- Mucus viscosity significantly impairs the effectiveness of alcohol-based disinfectants by limiting ethanol diffusion.
- This viscosity-mediated resistance poses a challenge for preventing healthcare-acquired infections.
- Findings suggest a need for developing improved disinfection strategies that overcome mucus barriers.