|CHAGGAR1, GURPREET - Purdue University|
|NKEMNGONG1, CARINE - Purdue University|
|LI, XIAOBAO - Johnson Diversey|
|TESKA, PETER - Johnson Diversey|
|OLIVER, HALEY - Purdue University|
Submitted to: Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2022
Publication Date: 3/11/2022
Citation: Chaggar1, G.K., Nkemngong1, C.A., Li, X., Teska, P.J., Haley, O.F. 2022. Hydrogen peroxide, sodium dichloro-s-triazinetriones and quaternary alcohols significantly inactivate the dry-surface biofilms of Staphylococcus aureus and Pseudomonas aeruginosa more than quaternary ammoniums. Microbiology. 168:001140. https://www.researchgate.publication/359179330.
Interpretive Summary: Bacteria readily form complex structures called biofilms, making them more tolerant to cleaning and disinfection practices. Biofilms may consist of harmful bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus that can result in equipment failure, product contamination, and infections. While cleaning and disinfection interventions target removal of “visible” dirt and “wet” biofilms, there is a knowledge gap about “dry” surface biofilms, which can easily persist in food and healthcare environments. We developed wet surface biofilm models of these bacteria using a dynamic CDC biofilm reactor. Wet biofilms were dehydrated in an incubator and tested them against seven disinfectants with different active ingredients. We found that there were no significant differences in the efficacies of disinfectants, irrespective of active ingredient, for dehydrated S. aureus biofilms. It was harder to inactivate P. aeruginosa dry biofilms than S. aureus biofilms. Overall, hydrogen peroxide, quaternary ammonium plus alcohol, and sodium dicholoro-s-triazinetrione based products were more efficacious than quaternary ammoniums for both tested species. These findings confirm bacteria persist in dry environments and the choice of disinfectants could highly impact disinfection efficacy.
Technical Abstract: Globally, healthcare-associated infections (HAI) are the most frequent adverse outcome in healthcare delivery. Although bacterial biofilms contribute significantly to the incidence of HAI, few studies have investigated the efficacy of common disinfectants against dry-surface biofilms (DSB). The objective of this study was to evaluate the bactericidal efficacy of seven Environmental Protection Agency (EPA)-registered liquid disinfectants against DSB of Staphylococcus aureus and Pseudomonas aeruginosa. We hypothesized that overall, there will be significant differences among the bactericidal efficacies of tested disinfectants by product type and active ingredient class. We also hypothesized that depending on the species, higher bactericidal efficacies against DSB will be exhibited after 24 h of dehydration compared to 72 h. Wet-surface biofilms of S. aureus and P. aeruginosa were grown following EPA-MLB-SOP-MB-19 and dehydrated for 24 and 72 h to establish DSB. Seven EPA-registered disinfectants were tested against dehydrated DSB following EPA-MLB-SOP-MB-20. Overall, quaternary ammonium plus alcohol, sodium dichloro-s-triazinetrione and hydrogen peroxide products were more efficacious against DSB than quaternary ammoniums for both tested species. While there was no significant difference in the log10 reductions between 24 and 72 h S. aureus biofilms, significantly higher log10 reductions were observed when products were challenged with 24 h P. aeruginosa DSB compared to 72 h P. aeruginosa DSB. Species type, active ingredient class and dry time significantly impact disinfectant efficacy against DSB of S. aureus or P. aeruginosa.