Microbiology and Antimicrobial Technology – Part 2

Dr Andrew Summerfield recently explained the progress of antimicrobial technology has made in reducing bacteria and its value in hospitals.

10th February 2014

Dr Andrew Summerfield recently explained the progress of antimicrobial technology has made in reducing bacteria and its value in hospitals.

Press release from BioCote® issued January 2014 titled ‘MICROBIOLOGY & ANTIMICROBIAL TECHNOLOGY – PART 2’

In part 1 of this article, Dr Andrew Summerfield described the progress antimicrobial technology has made in reducing bacteria. Here, he looks at a recent study which proves its value in hospitals.

Performance claims of biocides and disinfectants should be substantiated by the commercial organisations taking their products to market. Often laboratory-derived efficacy data are sufficient to make legally acceptable claims but it may be expedient for a manufacturer to present information describing their product’s performance that is directly relevant to that product’s intended use. Examples of information directly relevant to a product’s intended use include antibacterial performance against organisms specific to certain environments and the results from microbiological studies bespoke to particular environments.

The challenges of analysis

Unfortunately, custom studies addressing the microbiology of environments are often costly, time consuming and provide only a ‘snapshot’ understanding of what, in reality, is a complex, dynamic situation. Results from environmental studies need to be interpreted with more caution than those from a ‘simple’ antimicrobial laboratory test on swatches of biocide-treated polymer. In the laboratory product testing is performed under controlled conditions because our standard methods dictate as much. A single test organism is usually used whilst in the real world the same product may well be exposed to a multitude of microbial challenges from several independent sources and re-inoculation of the product is inevitable. Controlling such a situation for the purposes of a microbiological study is virtually impossible.

Generating meaningful insights into the in situ performance of antibacterial surfaces is, for the reasons outlined, challenging, but it is not impossible provided the science is robust. Teams must be dedicated to engaging in suitable ‘real world’ studies ranging from modest sample collection and recording work through to collaborating with partner companies and universities to generate novel data describing the in situ performance of antibacterial surfaces that are subsequently published as peer reviewed journal articles. In 2009, BioCote published the results of a study describing the performance of antibacterial surfaces in an acute healthcare environment in the Journal of Infection Prevention. This study added to the on-going debate about technologies and practices of value in supplementing standard infection control procedures. The paper’s authors highlighted the lack of data describing the performance of antimicrobial surfaces in situ.

Measuring the benefits

In brief, two comparable wards were selected from the acute unit for study. The first ward was modified by the introduction of numerous, diverse antimicrobial surfaces. The second ward underwent similar refurbishment as the first, but without the inclusion of antimicrobial technology. Normal clinical activity preceded in both environments as the investigators monitored key microbiological parameters on the surfaces of interest.

On average, bacterial contamination was over 95 per cent lower on all surfaces in the treated ward compared to the control ward. The study also produced the unexpected observation of reduced levels of bacterial contamination on untreated surfaces in the modified ward. The paper hypothesised that antibacterial surfaces play a role in mitigating the risks of cross contamination in a treated environment.

Other studies of antibacterial surfaces conducted by BioCote and collaborators with similar objectives have produced results and conclusions in general harmony with this prediction: surfaces demonstrating a highly efficacious antibacterial property by laboratory analysis demonstrate that property, to some degree, when applied to ‘real life’ environments.

One way to address the challenges of controlling an in situ microbiological study is to repeat the investigation to unrelated situations/environments that share only the presence of antibacterial surfaces. This approach can allow a persistent, universal antibacterial effect on the treated surfaces to be discerned because compared to their surroundings the antibacterial surfaces will always tend to a reduced level of bacterial contamination.

Fighting cross contamination

How does the information generated by in situ studies empower us to understand the potential benefits of antibacterial surfaces in the real world? As mentioned, a consistent finding of these studies is the on average lowering of the number of bacteria found contaminating antibacterial surfaces compared to related, but untreated surfaces. An obvious benefit, then, should be the reduction in cross contamination within the antibacterial environment and this parameter is, in theory, measurable.

Cross contamination by human hands is a major mechanism by which bacteria are distributed from a source to the surrounding environment and no one would seriously challenge the firmly entrenched view that hand washing is the single most effective way in which bacteria are inhibited from spreading. Therefore, breaking the chain of how cross contamination works is a potential benefit of antibacterial surfaces.

Disinfectants not sufficient

The application of traditional disinfectants is a mainstay of cleaning regimes. A disadvantage with disinfectants is their transient effect. The disinfectant does not act continuously on the surface it was applied to, so surface contamination will presumably reoccur at some point.

Disinfectant cleaning is therefore, necessarily, a repetitive process. Antibacterial surfaces, in contrast, operate continuously to reduce the number of viable bacteria contaminating them. There is a compelling mass of data showing treated materials from fabrics to laminates sustain their antibacterial effect over considerable periods of time.

It should be pointed out that antibacterial surfaces do not remove the need for normal cleaning to operate; rather the antibacterial activity of treated surfaces brings a hygiene benefit in between episodes of cleaning. This concept is supported by the results of in situ studies described above.

A growing industry

The antimicrobial industry has been forecast to continue growth in coming years. Over recent years antimicrobial technology has been applied to an increasing range of materials and product types which are then introduced into new industries and environments.

Often an evidence base is required for manufacturers and or end users to adopt antibacterial technology, but the literature describing the performance and benefits of antibacterial technology has now emerged and continues to swell.

It is important we continue to better understand this technology, particularly as new active substances are added to the portfolio of antibacterial products.

Scientific organisations and their commercial and academic collaborators are valuable in adding to our understanding of the technology and its benefits when it is applied to the contaminated real word.

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