In Microbiology, News & Views

The microbiome’s importance

We spend most of our modern lives in enclosed environments – offices, homes, cars, yet understanding of our interaction with the multitudinous microbes that co-inhabit those environments remains largely unknown. The presence and persistence of microbes impacting human health in the built environment is beyond question. Myriad studies have described the detection of disease-causing microbes, pathogens, from hygiene critical environments, hospitals, for example. What are the consequences on our health of spending time in the presence of these microbes and how can technology elucidate and solve points of concern?

For these reasons, the microbiology, the so-called microbiome, of the built environment has in the last fifteen years emerged as a key player in science and the plentiful funding driving its research is indicative of the importance governments have attached to its evidence-based conclusions and, where necessary, solutions.

Sharing the car’s microbiome

The microbiology of car interiors has attracted the attention of microbiologists and automotive manufacturers according to the issues mentioned above. Given that we typically sit in cars for more than 10 hours each week, the car interior is an environment that is captured by the need to understand the relationship between its microbiome and human health.

The microbial profile of a car’s interior will be a composition of the microbes we shed as drivers, plus those microbes deposited by co-users of the car and those carried by the incoming air. These three sources of microbial contamination will undoubtedly contribute pathogens to the car’s microbiome, not necessarily because the driver or passenger is suffering symptomatic infectious disease, but because these organisms are commonly carried asymptomatically as part of human flora. Of course, a driver or passenger with an infectious disease can be expected to shed the infectious agent causing the infection within the car interior alongside the multitude of other microbes they are continually releasing.

Pathogens persist on inanimate surfaces so there is clearly potential for the dissemination of infectious disease between car sharers because the car interior becomes contaminated and cross contamination between people is waiting to happen. The car interior is an acute example of the necessary combination of predisposing factors for cross contamination – multiple occupants in an enclosed space for extended periods, numerous common touch points in that environment and limited decontamination of the microbes.

Are cars making people ill – what does the science tell us?

The sensationalising of the story that pathogens are found in ‘dirty’ car interiors by the tabloid press is not without basis of fact. Scientists have published robust studies describing the detection of various human pathogens in car interiors and air conditioning systems. This article has made the point that such observations are to be expected in cars, as in any human-containing built environment because those important predisposing factors are present. Objective, scientific method allows the researchers to comment on the implications of their findings, so what does the car industry learn from the study data?

Car interior air quality, contributed to by counts of bacteria and fungi, needs to be considered as a public health issue, particularly in high traffic-density and engine-idling. Specific pathogens have been detected with specific car components. For example, Legionella bacteria have been repeatedly found in used cabin air filters. These bacteria are the cause of Legionnaire’s disease so their presence in car air filters suggests that filters have a role as the source of infection in car users. Additionally, the repeated detection of antibiotic resistant pathogens has been reported in car interiors. Given the concern associated with the widespread emergence of the so-called ‘superbugs’ cars, as vectors of their transmission, need to be considered within public health containment strategies. Confirming a car interior as a source of infection to other users of that car is not easy meaning the true situation is probably under-recognised.

Car cleaning

Advances in technology have facilitated the emergence of another scientific discipline, antimicrobial technology, specifically, antimicrobial chemical additives for manufacturing industries. Driven by the need to counteract undesirable microbial processes, for example, mould growth and microbially-mediated surface degradation, industrial chemists have developed additives that render any receiving material permanently antimicrobial by the incorporation of an active ingredient.

The additive and myriad receiving materials’ chemistries have been engineered to be compatible and sustainable; virtually any material can be treated simply by introducing the right additive during its manufacturing process, for example antimicrobial masterbatch blended into a polymer during moulding. Tier 1 and 2 manufacturers of components for car interiors – steering wheels, upholstery, fascia, air-conditioning systems – are nicely captured by this straightforward procedure.

Validation of treated components, via a quantitative assessment of their antimicrobial performance, is easily achieved by subjecting samples to the appropriate laboratory test. Thus, the supply chain is adjusted to include the supplier of the antimicrobial additive to the relevant tier 1 or 2 sub-contractor, who are operating under the instructions of the OEM.

The antimicrobial treatment

One notable published study presented this objective as the basis for the research; “Can automobile interior surfaces be designed to resist colonization by potential pathogens?” Colonisation by pathogens is unavoidable, the strategy here is to oppose the continued presence of undesirable microbes on surfaces within the car interior. The study deployed an antimicrobial coating to the steering wheel of normally used cars and samples collected from treated and untreated wheels as a comparative exercise. The study reported significantly lower numbers of pathogenic bacteria on antimicrobial steering wheels compared with the standard version in cars.

Increasing movement of people and microbes – risk reduction

At the time of writing, there are at least two major automotive manufacturers looking at the practicalities of incorporating antimicrobial technology into the interior of their cars. This innovative thinking has been prompted by the hygiene-related issues described in this article. Importantly, these automotive OEMs have arrived at the same solution-based thinking independently.

The rationale behind antimicrobial car interiors is strong and the robust, independent scientific data providing the facts continue to emerge to support the rationale. Indeed, the car interior environment may be viewed as a microcosm for transport of people in general because there are common denominators between commercial aircraft, cruise ships, train carriages, airport terminal passenger pods and cars. They all exist to move crowds of people between destinations and so they contain people sharing touch points for extended periods, they exhibit heavy microbial contaminated and are subject to limited decontamination measures.

Given that the mechanised movement of people is projected to increase in terms of passenger numbers, it is reasonable to consider that the public health issues associated with human transport will adopt a higher profile along with the various options for controlling risk through hygienic best practice. Antimicrobial car interiors may become standard as OEMs respond to the accumulating evidence describing the microbial risks routinely experienced by car sharers.

How BioCote® can support you

BioCote® premium additives can be integrated into a wide range of materials, including polymers, silicones, powder coatings, liquid paints, ceramics and textiles. If you would like to learn more about our antimicrobial technology or if you are looking to make your products antimicrobial, please contact a member of the BioCote® team today on +44 (0) 2477 712 489 or email us at [email protected]. Alternatively, you can contact us via the form below.

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