Effect of Antimicrobial Wipes on Hospital-Associated Bacterial and Fungal Strains

Background: Healthcare-associated infections (HAI) caused by multidrug-resistant organisms have emerged as a significant global issue, posing substantial challenges to healthcare systems. Low- and intermediate-level disinfectants are extensively utilized for cleaning and disinfecting surfaces in hospitals to mitigate environmental transmission of HAI. Therefore, the need for more effective and environmentally safe disinfectants is increasing. This study aimed to assess the effect of antimicrobial wipes used for surface cleaning and disinfection in healthcare environments.

Materials and methods: A microbe library comprising 188 bacterial and fungal isolates, including multidrug-resistant strains, was established and used to evaluate the antimicrobial effect of three types of antimicrobial wipes: A (didecyldimethylammonium chloride [DDAC] 0.31% and 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride [Si-QAC] 0.45%); B (benzalkonium chloride [BAK] 0.63%); and C (DDAC 0.5% and BAK 0.9%). The antimicrobial effect of the wipes was assessed and compared in three assays: rapid bactericidal effect assay of the three wipes, minimum inhibitory concentration (MIC) assay of DDAC and BAK, and a time-kill assay of the DDAC and Si-QAC combination.

Results: The rapid antimicrobial effect evaluation showed that both wipes A and C, which contain a combination of two quaternary ammonium compounds (QACs), exhibited similar antimicrobial effect (P=0.8234). Antimicrobial wipe A demonstrated better effect against Gram-positive bacteria and fungi than wipe C (P <0.05). The antimicrobial efficacy of the A wipe against Mycobacterium strains was superior to that of both the B and C wipes. Moreover, DDAC exhibited MIC₅₀ values that were 2 to 3-fold lower than those of BAK for Gram-negative bacteria and fungi. The time-kill assay results for the DDAC and Si-QAC combination exhibited a growth reduction of >3 logs for Staphylococcus aureus and Enterococcus faecium, whereas approximately 2 logs of reduction was observed for Escherichia coli and Pseudomonas aeruginosa at 3 hour.

Conclusion: The results suggest that antimicrobial wipes containing relatively lower concentrations of QAC (wipe A) achieve similar rapid bactericidal effect as that of those with higher concentrations (wipe C). For Gram-negative bacteria, including multidrug-resistant strains and fungal isolates, DDAC presented lower MICs compared with BAK. Furthermore, the combination therapy with DDAC and Si-QAC demonstrated enhanced efficacy compared to treatment with either agent alone, except in the case of Klebsiella strains. Further research is needed to develop antimicrobial wipes that minimize the environmental impact while ensuring effective disinfection.