A rapid model for developing dry surface biofilms of Staphylococcus aureus and Pseudomonas aeruginosa for in vitro disinfectant efficacy testing

Nkemngong, Carine A.; Voorn, Maxwell G.; Li, Xiaobao; Teska, Peter J.; Oliver, Haley F.

doi:10.1186/s13756-020-00792-9

Cited by 20 publications

(41 citation statements)

References 47 publications

(78 reference statements)

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“…We found that mean log 10 densities per coupon from this study were comparable to the ranges previously reported by Nkemngong et al, 2020 [34]. We found that overall and irrespective of dry time, CL, SH, HP and QA disinfectants were signi cantly more bactericidal against DSB of S. aureus than QT disinfectants.…”

Section: Discussionsupporting

confidence: 90%

“…Our study found differences in the overall bactericidal e cacy of disinfectants against DSB of S. aureus and P. aeruginosa after prolonged dehydration for 24 h and 72 h. While there was no signi cant difference in log 10 reductions between 24 h and 72 h DSB of S. aureus, the reverse was true for DSB of P. aeruginosa as 72 h DSB of P. aeruginosa were harder to kill than their 24 h counterparts. In a previous study by our group, we found that 100% of P. aeruginosa DSB established at a dehydration temperature of 21°C were encased in EPS while this was true for only 92% of S. aureus DSB established at 25°C [34]. The consistent presence of EPS on DSB of P. aeruginosa at dehydration time points from 24 h to 120 h as previously demonstrated by our group suggested that older DSB of P. aeruginosa developed using our model may be encased in more EPS; making them harder to kill [34].…”

Section: Bactericidal E Cacy Varies By Strain After Prolonged Dehydramentioning

confidence: 79%

“…Bacteria strains and disinfectants tested in this study DSB of S. aureus ATTC-6538 and P. aeruginosa ATCC-15442 were established on borosilicate glass coupons (1.27 ± 0.013 cm; Biosurface Tech, Inc.) following Nkemngong et al, 2020 [34]. These strains were selected as they are standard strains of choice for disinfectant e cacy testing [31].…”

Section: Methodsmentioning

confidence: 99%

“…After wet surface bio lms were established through the batch and CSTR phases, rods from the CDC bio lm reactor; each holding three borosilicate glass coupons were dehydrated for 24 h and 72 h at 25°C or 21°C for S. aureus and P. aeruginosa, respectively. Dry times and dehydration temperatures were informed by Nkemngong et al, 2020 [34].…”

Section: Methodsmentioning

confidence: 99%

“…To the best of our ndings, no studies have evaluated the bactericidal e cacy of disinfectants against dry surface bio lms of S. aureus and P. aeruginosa established at different dehydration time points consistent with routine cleaning and disinfection schedules recommended by the CDC [33]. In a previous study, our group developed a rapid model for establishing DSB of S aureus and P. aeruginosa at different time points and at mean log 10 densities su cient for disinfectant e cacy testing [34]. In this study, we evaluated the bactericidal e cacy of seven liquid disinfectants against DSB of S. aureus and P. aeruginosa after 24 h and 72 h of dehydration.…”

Section: Introductionmentioning

confidence: 99%

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Disinfectant Efficacy Against Dry Surface Biofilms of Staphylococcus Aureus and Pseudomonas Aeruginosa Is Product, Time Point and Strain Dependent

Nkemngong¹,

Chaggar²,

Li³

et al. 2021

Preprint

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Background: 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 disinfectants against DSB of Staphylococcus aureus and Pseudomonas aeruginosa. We hypothesized that overall, hydrogen peroxides, sodium dichloro-s-triazinetrione and quaternary ammonium compounds plus alcohol disinfectants will be more bactericidal against DSB than quaternary ammonium. We also hypothesized that regardless of differences in product chemistries, higher bactericidal efficacies against DSB will be exhibited after 24 h of dehydration compared to 72 h.Methods: Wet surface biofilms of S. aureus and P. aeruginosa were grown following EPA-MLB-SOP-MB-19 and dehydrated for 24 h and 72 h to establish DSB. Seven EPA-registered disinfectants were tested against dehydrated DSB following EPA-MLB-SOP-MB-20. Results: Overall, quaternary ammonium plus alcohol, sodium dichloro-s-triazinetrione, and hydrogen peroxide products were more efficacious against DSB than quaternary ammoniums for both tested strains. While there was no significant difference in biofilm killing efficacies between 24 h 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. Conclusion: Strain type, active ingredient class, and dry time significantly impact disinfectant efficacy against DSB of S. aureus or P. aeruginosa.

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Section: Discussionsupporting

confidence: 90%

Section: Bactericidal E Cacy Varies By Strain After Prolonged Dehydramentioning

confidence: 79%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Disinfectant Efficacy Against Dry Surface Biofilms of Staphylococcus Aureus and Pseudomonas Aeruginosa Is Product, Time Point and Strain Dependent

Nkemngong¹,

Chaggar²,

Li³

et al. 2021

Preprint

Self Cite

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Fouling Release Mechanism of an Octopus‐Inspired Smart Skin

Mamman,

Johnson,

Weerakkody

et al. 2024

Adv Funct Materials

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This work proposes an octopus‐inspired smart skin for fouling release. The skin consists of twisted spiral artificial muscles (TSAMs) embedded between two layers of elastomer. Upon electro‐thermal actuation, TSAMs undergo vertical displacement (similarly to octopus’ papillae dermal muscles) and mechanically deform the top layer of the skin where the biofilm is attached. The release is achieved by generating a critical strain on the skin's top layer. In this paper, a physics‐based mechanical model is proposed to describe the fouling release mechanism of the smart skin. The model relates the critical strain to the mechanical properties of the biofilm, as well as the mechanical and electro‐thermal properties of the TSAMs. The model is experimentally validated, and a robust controller is implemented to achieve the desired critical strain and then perform release for two different types of biofilms: bacterial‐based Escherichia coli and diatom‐based Amphora coffeaeformis.

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A new spray‐based method for the in‐vitro development of dry‐surface biofilms

et al. 2023

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The inanimate environment immediately surrounding the patient in healthcare facilities is a reservoir of microorganisms embedded in dry‐surface biofilms (DSB). These biofilms, first highlighted in 2012, are increasingly studied, but currently available in‐vitro models only allow for the growth of semi‐hydrated biofilms. We developed a new in‐vitro method under actual dehydration conditions based on the hypothesis that surface contamination is mainly due to splashes of respiratory secretions. The main objective of this study was to show that the operating conditions we have defined allowed the growth of DSB with a methicillin resistant Staphylococcus aureus strain. The second objective was to show that extended‐spectrum beta‐lactamase‐producing Enterobacteriaceae, that is, Klebsiella pneumoniae and Enterobacter cloacae were also able to grow such biofilms under these conditions. Monobacterial suspensions in sterile artificial saliva (SAS) were sprayed onto polyethylene surfaces. Nutrients and hydration were provided daily by spraying SAS enriched with 20% of Brain Heart Infusion broth. The primary outcome was mean surface coverage measured by image analysis after crystal violet staining. The method applied to S. aureus for 12 days resulted in reproducible and repeatable DSB consisting of isolated and confluent microcolonies embedded in extracellular polymeric substances as shown in scanning electron microscopy images. Similar DSB were obtained with both Enterobacteriaceae applying the same method. No interspecies variation was shown between the three strains in terms of surface coverage. These first trials are the starting point for a 3‐year study currently in process.

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A rapid model for developing dry surface biofilms of Staphylococcus aureus and Pseudomonas aeruginosa for in vitro disinfectant efficacy testing

Cited by 20 publications

References 47 publications

Disinfectant Efficacy Against Dry Surface Biofilms of Staphylococcus Aureus and Pseudomonas Aeruginosa Is Product, Time Point and Strain Dependent

Disinfectant Efficacy Against Dry Surface Biofilms of Staphylococcus Aureus and Pseudomonas Aeruginosa Is Product, Time Point and Strain Dependent

Fouling Release Mechanism of an Octopus‐Inspired Smart Skin

A new spray‐based method for the in‐vitro development of dry‐surface biofilms

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