Data Availability: All relevant data are within the paper and its Supporting Information files. Competing interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: Goldshield products and technical information were obtained free of charge from Goldshield Industries Europe Ltd, Unit C, Lincoln Lodge Farm, Castlethorpe, MK19 7HJ. Goldshield Industries were not involved in the experimental design, collection, analysis or interpretation of data or in writing the manuscript or decision to publish. Healthcare acquired infections HAIs are directly and indirectly responsible for increased morbidity and mortality rates in hospitals worldwide.
A further consequence is the financial burden associated with these infections, measured in terms of increased length of patient stay, decreased bed availability as a result and the extra cost of antibiotic therapy to treat the infection. As a consequence, there is increasing interest from industrial, research and development and healthcare sectors in the development of viable and cost-effective alternative methods of reducing HAI.
Such microorganisms have been shown to survive on inanimate surfaces for extended periods of time—for example S. Clostridium difficile infections CDI , the most common HAI type in Europe [ 7 ] are attributed in part to the persistence of infectious spores on hospital surfaces for up to 5 months [ 5 ]. Bacteria capable of forming biofilms, such as P. Thus vegetative cells, spores, or biofilms present a threat of infection and indeed a recent report identified biofilm within water taps as the cause of a series of neonatal P.
Evidence of a direct correlation between environmental contamination and infection rates exists [ 5 , 10 , 11 , 12 ] and microbial contamination of the environment has been shown to act as a source of infection that is directly responsible for transmission of organisms to patients [ 12 ]. The most problematic areas tend to be high-touch points such as bed rails, door handles, table top surfaces, bedding mattress , television controls and staff uniforms [ 13 ]. As long as these organisms persist in a hospital or healthcare facility environment they remain a source of infection and therefore, hospitals have implemented revised and improved infection control practices in order to reduce and ideally eradicate environmental microbial contamination.
This is achieved primarily by the use of disinfectants and detergents, although the precise disinfectant used will be dependent on multiple factors. For example, areas of high risk such as operating theatres will require multiple cleans per day, whereas patient waiting rooms may be cleaned only once per day.
Copper surfaces reduce the rate of healthcare-acquired infections in the intensive care unit.
The choice of disinfectant agent is also multifactorial: body fluid spillages will normally require higher level disinfectants than those used in routine cleaning. As a result, hospitals will use a variety of products including ethyl alcohol in hand rubs and gels, Quaternary ammonium compounds QACs , chlorine-releasing agents and peroxygen sterilants [ 15 ].
Nonetheless, current cleaning methods have in several instances been shown to be ineffective. Work by French et al. Recurrence of contamination on surfaces, post disinfection, is therefore a significant issue and this is especially true of high-touch surfaces [ 16 ]. Given the available evidence for the ineffectiveness of cleaning and rapid recontamination of surfaces, there is currently much interest in alternative approaches to the problem. The development of intrinsically anti-microbial surfaces that incorporate a variety of agents to kill microbes may be considered a useful strategy.
Alternatively, the use of specialised agents that are capable of preventing surface contamination, or that exhibit a residual antimicrobial activity post-disinfection, could be employed, and such products have recently been highlighted as of potential utility in the healthcare setting [ 17 ].
One such antimicrobial product is Goldshield, distributed by Goldshield Technologies Ltd. This is a patented, water soluble organosilane, coupled with a quaternary ammonium compound that is designed to coat surfaces with a protective antimicrobial layer to prevent microbial contamination. In this paper we report the bactericidal and anti-biofilm of GS5 technology against 11 common healthcare associated pathogens.
Phosphate Buffered Saline Oxoid, UK was prepared in deionised water and steam sterilised in an autoclave prior to use.
Beware the Trojan Horse – a timely reality check about re‐using single‐use devices
Two model surfaces were used. These were chosen as representative organisms of the type causing HAIs commonly seen in hospitals [ 18 ] and included Gram positive organisms, Gram negative organisms and Mycobacteria. Mycobacterium smegmatis was used as it is a fasting-growing model Mycobacterium species [ 19 ]. Three disinfectant agents used GS5, Actichlor and Distel are classed bactericidal surface disinfectants. The characteristics of these antimicrobial agents are summarised in Table 1.
To determine directly the bactericidal activity of GS5, a suspension contact time assay was completed; varying concentrations of GS5 were mixed with S. Bacteria were enumerated by dilution plating 0.
Three biologically independent experiments were performed. To investigate the residual activity of surface disinfectants a protocol was developed from the EN standard and the work of Baxa et al.
The l Steel surface samples were sprayed with either GS5, Actichlor, Distel or sterile water no treatment control using a hand spray. The test surfaces were left to dry in the sterile environment of a category 2 cabinet Biomat.
Bacteria were left on the surfaces for 45 min, and then viable cells recovered in 10 ml of sterile PBS by vortexing for 2 min. Following recovery of bacteria from the surfaces each surface was individually washed using sterile PBS, air dried and stored in a sterile storage box.
gms | German Medical Science
These surfaces were then re-challenged with S. This re-challenge was repeated at 3-day intervals over 15 days. A selection of 10 different bacteria, representative of important HAI, were individually tested on l Steel and Formica. Testing was performed once to determine the maximum antimicrobial effect for a freshly treated surface.
The protocol was as described above, but without re-challenge and only the activity of GS5 was assessed. Pseudomonas aeruginosa DSM biofilms were grown in well microtiter plates 4 wells per treatment and these were stained with 0. An overnight culture of P. At defined time points 8 h, 12 h, 24 h, 48 h, 72 h and 96 h biofilm production was assessed. The medium containing planktonic cells was removed and wells stained with 1. Unbound crystal violet Sigma-Aldrich, UK was removed and stained wells washed twice with 2ml sterile PBS following which bound crystal violet was solubilised using 1.
Each experiment was repeated on three separate occasions. For bactericidal testing, log 10 changes in viable bacterial numbers, compared to untreated controls was determined. Data was imported to Graphpad Prism 6.
101 infection control products to know | 2018
Statistical analysis was completed using SPSS v We firstly wished to determine if GS5 was effective against bacteria in solution, prior to surface testing. We hypothesised that a solution of GS5 at working concentration would exhibit a bactericidal effect against a suspension of bacteria. The direct antibacterial effects of GS5 against S. GS5 exhibited bactericidal actions at all concentrations after 5min contact time as shown in Fig 1 0.
GS5 is reported to form covalent bonds with surfaces, thereby leaving a nanoscale antimicrobial coating which kills microbes that encounter that surface. This, it is claimed, makes GS5 a more effective product due to its residual antimicrobial activity compared to other disinfectants. We designed an experiment to test this hypothesis by determining the residual antimicrobial effect of GS5, Actichlor and Distel.
The bactericidal activity of the three surface disinfectant agents was tested against S. Following subsequent re-challenge of treated surfaces with S. For subsequent testing of the GS5 product, the maximum effect time point day 0 was used. GS5 exhibited prolonged antibacterial activity 6 days whereas Actichlor and Distel showed no antibacterial activity after day 0.
Baxa et al. We therefore tested GS5 against a range of healthcare acquired infection microorganisms on l Steel or Formica to determine bactericidal effect. As hypothesised, GS5 treated surfaces did indeed exhibit a bactericidal effect against all ten tested microorganisms, and this effect was observed on both Formica and steel.
The average Log 10 reduction on steel surfaces for all bacteria tested was 0. Walker et al. Given the efficacy of GS5 against a range of HAI microbes, we hypothesised that a GS5-treated surface would impede the development of bacterial biofilms. Having observed that P. Grey columns representative of pre-treated samples; black bars representative of untreated controls. Images A and B show development of extensive biofilm on untreated surfaces.
Image D shows GS5 treated surface biofilm at 48 h: biofilm development and cell viability is similar to the untreated control. Only a single published report exists which details the effects of GS5 used as a surface biocide.