Staphylococcus aureus dry-surface biofilms are not killed by sodium hypochlorite: implications for infection control

Almatroudi, Ahmad; Gosbell, Iain B; Hu, Honghua; Jensen, Slade O.; Espedido, Björn A.; Tahir, Shamaila; Glasbey, Trevor; Legge, P; Whiteley, Greg S.; Deva, Anand K.; Vickery, Karen

doi:10.1016/j.jhin.2016.03.020

Cited by 94 publications

(88 citation statements)

References 22 publications

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“…Almost 6 log 10 reduction was achieved which could be compared to results showed by Almatroudi et al . () where more than 7 log 10 of bacteria in DSB were removed/killed by treatment with 1000 ppm NaOCl. Although, NaOCl treatment significantly lowered (Two‐way anova ; P < 0·05) the transfer of bacteria from dry surface biofilms compared to the absence of treatment, it was significantly less effective when DSB were formed in the presence of organic load (Table ).…”

Section: Resultsmentioning

confidence: 99%

Artificial dry surface biofilm models for testing the efficacy of cleaning and disinfection

Ledwoch

Said

Norville

et al. 2019

Lett Appl Microbiol

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Significance and Impact of the Study: The widespread presence of biofilms on dry surfaces in healthcare settings has been recently documented. These dry surface biofilms (DSB) present an unprecedented challenge to cleaning and disinfection processes. Here, we describe a practical efficacy protocol based on an in vitro Staphylococcus aureus DSB model. The protocol measures reduction in viability, transferability and biofilm regrowth post-treatment to provide altogether a practical assessment of product efficacy against dry surface biofilms. AbstractDry surface biofilms (DSB) harbouring pathogens are widespread in healthcare settings, are difficult to detect and are resistant to cleaning and disinfection interventions. Here, we describe a practical test protocol to palliate the lack of standard efficacy test methods for DSB. Staphylococcus aureus DSB were produced over a 12-day period, grown with or without the presence of organic matter, and their composition and viability were evaluated. Disinfectant treatment was conducted with a modified ASTM2967-15 test and reduction in viability, transferability and biofilm regrowth post-treatment were measured. Dry surface biofilms produced over a 12-day period had a similar carbohydrates, proteins and DNA content, regardless of the presence or absence of organic matter. The combination of sodium hypochlorite (1000 ppm) and a microfiber cloth was only effective against DSB in the absence of organic load. With the increasing concerns of the uncontrolled presence of DSB in healthcare settings, the development of effective intervention model in the presence of organic load is appropriate for the testing of biocidal products, while the use of three parameters, log 10 reduction, transferability and regrowth, provides an accurate and practical measurement of product efficacy.Staphylococcus aureus dry surface biofilm model K. Ledwoch et al.

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Section: Resultsmentioning

confidence: 99%

Artificial dry surface biofilm models for testing the efficacy of cleaning and disinfection

Ledwoch

Said

Norville

et al. 2019

Lett Appl Microbiol

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“…Previous studies have demonstrated that chemicals such as hypochlorite are consumed by the surface layers of the biofilm neutralizing the disinfectant before it can penetrate into deeper layers [20], making hydrated biofilm more tolerant than planktonic cells to these disinfectants [12]. However, a study on the efficacy of hypochlorite against DSB found that this semi-dehydrated biofilm was more tolerant to hypochlorite than hydrated biofilm [11]. The water content of hydrated S. aureus biofilm grown in the CDC bioreactor is 90%, whilst that of DSB is 61% [21].…”

Section: Discussionmentioning

confidence: 99%

“…Within DSB, bacteria are highly protected from desiccation, with approximately 50% surviving for over 12 months without nutrition or hydration [7]. Bacteria incorporated into hydrated biofilms have increased tolerance to removal by cleaning agents [10] and disinfectants [11,12]. However, Almatroudi et al [11] have shown S. aureus DSB to have more tolerance to chlorine disinfection than biofilms, and may, therefore, act as a constant source of pathogenic bacteria.…”

Section: Introductionmentioning

confidence: 99%

Effect of disinfectant formulation and organic soil on the efficacy of oxidizing disinfectants against biofilms

Chowdhury

Rahman

et al. 2019

Journal of Hospital Infection

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Background: Biofilms that develop on dry surfaces in the healthcare environment have increased tolerance to disinfectants. This study compared the activity of formulated oxidizing disinfectants with products containing active ingredients against Staphylococcus aureus dry-surface biofilm (DSB) alone. Methods: DSB was grown in the CDC bioreactor with alternating cycles of hydration and dehydration. Disinfectant efficacy was tested before and after treatment with neutral detergent for 30 s, and in the presence or absence of standardized soil. Biofilms were treated for 5 min with peracetic acid (Surfex and Proxitane), hydrogen peroxide (Oxivir and 6% H 2 O 2 solution) and chlorine (Chlorclean and sodium dichloroisocyanurate tablets). Residual biofilm viability and mass were determined by plate culture and protein assay, respectively. Findings: Biofilm viability was reduced by 2.8 log 10 for the chlorine-based products and by 2 log 10 for Proxitane, but these products failed to kill any biofilm in the presence of soil. In contrast, Surfex completely inactivated biofilm (6.3 log 10 reduction in titre) in the presence of soil. H 2 O 2 products had little effect against DSB. Biofilm mass removed in the presence and absence of soil was <30% by chlorine and approximately 65% by Surfex. Detergent treatment prior to disinfection had no effect. Conclusion: The additives in fully formulated disinfectants can act synergistically with active ingredients, and thus increase biofilm killing whilst decreasing the adverse effect of soil. It is suggested that purchasing officers should seek efficacy testing results, and consider whether efficacy testing has been conducted in the presence of biological soil and/or biofilm.

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“…It is possible that cleaners with biocidal activity against MRSA exert selective pressure, contributing to expansion of the MDR MRSA reservoir if strains carry genes for disinfectant resistance, such as qacA (24). Prior studies have shown that certain disinfectants are less effective against biofilm-producing S. aureus strains; we did not test our environmental strains for biofilm production (25,26). Further research needs to be done to replicate and elucidate the mechanism of this effect.…”

Section: Discussionmentioning

confidence: 99%

Multidrug and Mupirocin Resistance in Environmental Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates from Homes of People Diagnosed with Community-Onset MRSA Infection

Shahbazian

Hahn

Ludwig

et al. 2017

Appl Environ Microbiol

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Patients with community-onset methicillin-resistant (CO-MRSA) infections contribute to MRSA contamination of the home environment, and may be re-exposed to MRSA strains from this reservoir. This study evaluates One Health risk factors that focus on the relationship between humans, animals and the environment for increased prevalence of multiple antimicrobial resistant MRSA in the home environment. During a trial of patients with CO-MRSA infection, MRSA was isolated from the household environment at baseline and three months later, following randomization of patients and household members to mupirocin-based decolonization therapy or education control. Up to two environmental MRSA isolates per visit were tested. MRSA isolates were identified in 68% (65/95) of homes at baseline (=104 isolates) and 51% (33/65) of homes three months later (=56 isolates). Rates of MDR were 61% at baseline and 55% at the three-month visit. At baseline, 100% (14/14) of MRSA isolates from rural homes were MDR. While antimicrobial use in humans or pets was associated with an increased risk for the isolation of MDR MRSA from the environment, clindamycin use was not associated risk for isolation of MDR MRSA. Two (5%) of 39 homes that were randomized to mupirocin treatment, but none of the control families, had incident low-level mupirocin resistant MRSA isolated at three months. Among patients recently treated for a CO-MRSA infection, MRSA and MDR MRSA were common contaminants in the home environment. This study contributes to evidence that occupant use of antimicrobial drugs--except clindamycin--is associated with MDR MRSA in the home environmental reservoir. MRSA is a common bacterial agent implicated in skin and soft tissue infections (SSTIs) in both community and healthcare settings. Patients with CO-MRSA infections contribute to MRSA contamination and may be re-exposed to MRSA strains from these reservoirs. People interact with natural and built environments, therefore understanding the relationships between humans and animals as well as characteristics of environmental reservoirs is important to advance strategies to combat antimicrobial resistance. Household interactions may influence the frequency and duration of exposure, which in turn may impact the duration of MRSA colonization or probability for recurrent colonization and infection. Therefore, MRSA contamination of the home environment may contribute to human and animal recolonization and decolonization treatment failure. The aim of this study was to evaluate One Health risk factors that may be amenable to intervention and may influence the recovery of MDR and mupR resistance in CO-MRSA isolates.

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Staphylococcus aureus dry-surface biofilms are not killed by sodium hypochlorite: implications for infection control

Cited by 94 publications

References 22 publications

Artificial dry surface biofilm models for testing the efficacy of cleaning and disinfection

Artificial dry surface biofilm models for testing the efficacy of cleaning and disinfection

Effect of disinfectant formulation and organic soil on the efficacy of oxidizing disinfectants against biofilms

Multidrug and Mupirocin Resistance in Environmental Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates from Homes of People Diagnosed with Community-Onset MRSA Infection

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