Fast-cycle hydrogen peroxide nebulization against frequent healthcare-associated micro-organisms: efficacy assessment

Effect of prolonged exposure to disinfectants in the antimicrobial resistance profile of relevant micro-organisms: a systematic review

BACKGROUND

Antimicrobial resistance (AMR) constitutes a major global health threat, to a very large extent due to the inadequate use of antibiotics. Additionally, the misuse of disinfectants can also trigger the selection of resistant clones, where micro-organisms develop an adaptative response and progress to resistance mechanisms. Cross-resistance may occur when a biocide's selective pressure induces antimicrobial resistance.

AIM

To acknowledge the potential relationship between repeated and/or prolonged exposure to disinfectants and antimicrobial resistance profile adjustment.

METHODS

This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies published until December 2023 that were related to the interaction between disinfectants and antimicrobials were included. Further selection was based on the methodology of exposure.

FINDINGS

Selected studies included testing about 'exposure to sublethal concentrations' for seventeen disinfectants. The mechanism of action for the majority of the disinfectants involved interactions with the cell membrane. Chlorhexidine was the most studied disinfectant.

CONCLUSION

Adaptation phenomena related to disinfectant exposure were documented and development of cross-resistance to antimicrobials was verified for several species, including Streptococcus spp., Klebsiella pneumoniae, Acinetobacter baumannii, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida spp. Changes associated with disinfectant exposure also influenced biofilm formation, colony morphology, and efflux pump activity - three relevant determinants of loss of antibiotic efficacy.

Efficacy assessment of different time-cycles of nebulized hydrogen peroxide against bacterial and yeast biofilm

BACKGROUND

The prevention of healthcare-associated infections requires a continuous effort. In order to achieve better practical results, the control of environmental microbial biofilms with effective disinfection strategies should be addressed.

AIM

This study aims to test the efficacy of different time-cycles of nebulized H₂O₂ against bacterial and yeast dry biofilm.

METHODS

The efficacy of a standard cycle (SC) and of a fast cycle (FC) of nebulized H₂O₂ was compared. Microbial biofilms were previously grown on different material coupons. The biofilm metabolic activity was determined by XTT assay and the biofilm total biomass by crystal violet assay.

FINDINGS

Regarding the efficacy of nebulized H₂O₂ against biofilms, the mean reduction of metabolic activity of the SC was 55.2% (±19.4%), comparing to a reduction of 50.4% (±17.7%) of the FC. The mean reduction of total biomass of the SC was 45.5% (±22.7%), versus 46.7% (±21.7%) of the FC. No statistical significant differences were found when comparing the tested cycles and distinct materials.

CONCLUSION

H₂O₂ nebulization was found to exhibit a good efficacy against healthcare-associated microbial dry biofilms. Moreover, similar efficacies were found between the tested cycles.