GB2475028A

GB2475028A - Microbial transmission blocking film for hard surfaces

Info

Publication number: GB2475028A
Application number: GB0914421A
Authority: GB
Inventors: Richard Hugh Lawson; Paul Stuart Dryden
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-08-18
Filing date: 2009-08-18
Publication date: 2011-05-11
Also published as: GB0914421D0

Abstract

This invention is intended to reduce the transmission of skin transmission of pathogenic microbes (viruses and bacteria) mediated through frequently handled objects such as door handles, light switches, door push plates, tap (faucet) handles, toilet levers and similar objects by providing an antiseptic overlay to these objects such that the surface will retain anti-microbial activity for a substantial number of hours following its application. The overlay may be in the form of an elasticated cover, an adherent film, or a barrier layer comprising a paint, polymer or gel. The microbiocidal agent may be an acid, alkali, an alcohol, metallic ions, boric acid, iodine, an oxidising agent or a disinfectant.

Description

PATENT APPLICATION

MICROBIAL TRANSMISSION BLOCKING FILM FOR HARD SURFACES

A proposal to develop a lasting antiseptic barrier on frequently touched objects.

Field of the Invention

This invention relates to a method of preventing transmission of viable microbiological particles from hand to hand mediated by frequently touched objects such as taps, door handles, door push-plates, light switches and devices to activate flushing toilets.

Background

Cross contamination of microbes presents a constant problem for institutions, particularly hospitals. Multi-Resistant Staphylococcus Aureus (MRSA), Norovirus, and the 2009 pandemic of influenza virus A/H1N1 are examples of organisms that are transmissible from human to human both by droplet and skin contact -including skin contact with inanimate objects. The proposal presented here is designed to reduce skin transmission mediated through frequently handled physical objects such as taps, door handles, toilet levers and chains -hereinafter called "objects".

Present official advice regarding skin transmission is that persons in contact with the influenza virus and other transmissible microbes should wash their hands frequently by using soap and water or alcohol hand rubs, and that hard surfaces such as work-tops and the objects mentioned are also to be sterilised frequently. These methods are effective in removing past microbiological loads, but the cleansed surfaces are vulnerable to becoming re-contaminated as soon as they are touched by hands contaminated with the virus.

This vulnerability to re-contamination happens in the case of skin immediately after washing with water, so that the act of closing off a tap after washing can result in re-contamination. In the case of alcohol skin cleansers vulnerability occurs as soon as the alcohol has evaporated, which takes about one minute.

Viral epidemics and pandemics are of particular concern at the present time. The A/H1N1 virus can remain viable on physical objects for varying lengths of time depending on the material and physical conditions. The Royal College of General Practitioners document "Preparing for Pandemic Influenza" (http://bit.ly/4Spwy) states that: 4.13.1 Flu viruses can survive for more than a day on hard non-porous surfaces such as stainless steel. Experiments have shown that flu viruses can be transferred from these contaminated surfaces onto hands up to 24 hours later.

4.13.2 Because the virus survives for a long time on frequently touched hard surfaces (eg doorknobs) frequent cleaning is essential to control the spread of infection.

The obvious flaw in the advice given is that as with hand washing, object cleaning only removes past contamination, and the object becomes re-contaminated as soon as it is touched by a person with virus on the skin.

The aim of reducing cross contamination through this route will become even more urgent if the H5N1 Avian virus develops the ability to be passed from human to human.

Problem solved by the present invention The present proposal is aimed at addressing the problem of re-contamination and resultant cross-infection by covering frequently-handled objects which are vulnerable to contamination with an antiseptic overlay comprising a barrier impregnated with agents that can inactivate bacteria and viruses. It will be of use in institutions such as hospitals, residential homes, nursing homes, schools, commercial organisations, and also in the domestic situation where a patient suffering with an infection is being nursed.

Effect of the present invention The present invention will place a physical barrier impregnated with an effective chemical agent over the surface of objects vulnerable to contamination in order to reduce or eliminate the possibility of cross-infection through touching and re-touching of the surface of the object coated with the invention.

Means for realisation of the aims of the present invention We offer two options for realizing this objective: 1. Provision of elasticated covers impregnated with an antiseptic agent. These covers would be designed to be fitted onto common shapes of taps, levers, and handles in a way that they can be removed and replaced, but so that they will stay in place in common use.

2. Provision of an adherent film impregnated with microbicidal agents which can be applied to said objects.

Of these two options we prefer (2) for general use because of the complexity of designing a series of elasticated caps for the variety of shapes of handles &c., as well as the technical problems involved in embedding the antiseptics in the elasticated material. However, it may prove advantageous to use option (1) in objects such as handles of sprung doors where greater than average force has to be applied to open the door, since it may prove that a film could wear off rapidly in this situation.

Description of the invention

The Transmission Blocking film consists of two elements, both of which are available on the market at present: the film and the antiseptic.

The film will be capable of being applied quickly and easily by wiping the object (tap, door handle, lever or other frequently touched surface) with a cloth, sponge or brush carrying a substance which will adhere to the surface and persist there for a length of time determined by the properties of the substance and the frequency with which it is touched.

The antiseptic will be chosen for its ability to inactivate or kill a broad spectrum of micro-organisms, prioritising those that pose a problem of cross-contamination such as MRSA, Norovirus, and Influenza viruses.

Desired Film Properties The precise substance chosen for the final embodiment of the present invention will be determined by performance studies; it may take the form of a paint, emulsion, polymer, or gel. Hereinafter we will refer to the substance as a film.

The film used as vehicle for the antiseptic would need to be capable of adhering to metals without staining or corroding the object in a way that would adversely affect its structure or appearance. The film would need to be robust enough to withstand wearing off after a few uses, and also soluble in common solvents such as water or alcohol in order to allow the object to be cleaned and re-covered with the film. Durability would depend on the amount of use applied to the object, but we aim for the film adherence, with effective microbicidal properties, typically to last for 24 hours or more. The film would need to be substantially non-sticky to hands touching it, although the transfer of an imperceptible amount of film and antiseptic to the hand, would be advantageous in terms of reducing cross infection. The film must be non-toxic and non-allergenic. It would need to be able to contain the antiseptic agent without reacting with it, and must allow the antiseptic agent to migrate from the deeper layers of the film to surface layers where a certain amount of the antiseptic will be removed at each contact.

There may be found a variety of substances already available to fulfil these criteria, but the most likely candidate will be a gel, since the molecular structure of a gel will be most likely to satisfy the above criteria.

Microbicidal agents A variety of potentially suitable microbicides or antiseptics are already available.

Viruses are relatively fragile organisms, typically covered with a lipid coating, and which are inactivated by low humidity, high temperatures, and the following commonly used agents: 1. acids 2. alkalis 3. alcohol 4. metallic ions, e.g. silver 5. boric acid 6. Iodine 7. oxidising agents such as hydrogen peroxide and hypochiorites 8. disinfectants such as Chlorhexidine, Quaternary Ammonium Compounds, and related compounds.

Of these, we would prefer either or both of 7 and 8 as suitable for use in this proposal.

Since both the film and the antiseptic are available on the market, the inventive step in this proposal is to identifr the compounds which when in combination will most effectively satisr the aims and purpose of the invention set out above.

We are currently screening commercially available gels and microbicides/antiseptics to determine the compounds whose properties best match the criteria set out above. Criteria that will determine the choice will include: 1. absence of any reaction between film and agent that will adversely affect either 2. ability of agent to migrate to the surface of the film 3. durability and chemical stability of the mixture of film and agent 4. absence of irritation and allergenic properties of said mixture Experimentation will include 1. assessment of the absence of viable virus or bacterial particles on the surface of the film 2. assessment of the time that microbicidal effectiveness continues 3. assessment of the effect of frequent touching on the surface of the film, in particular whether skin cells or other detritus become deposited on the surface of the film, and if so, whether these can form a locus where re-contamination can occur, and if so, how much usage can occur before such a locus can appear.

Claims

CLAIMS1. An antiseptic overlay for lasting protection of frequently touched surfaces from contamination by microbial pathogens which comprises a barrier layer impregnated with an effective amount of one or more microbicidal agents.
2. An antiseptic overlay according to claim 1, which is in the form of an elasticated cover.
3. An antiseptic overlay according to claim 1, which is an adherent film.
4. An antiseptic overlay according to claim 3, in which the barrier layer is a paint, polymer or gel.
5. An antiseptic overlay according to any of claims 1 to 4, in which the microbicidal agent/s is/are selected from the group of acids, alkalis, alcohol, metallic ions, boric acid, iodine, oxidising agents and disinfectants.
6. An antiseptic overlay according to any of claims 1 to 5, in which the microbicidal activity of the microbicidal agent persists for at least 24 hours.
7. A method for preventing the contamination of frequently touched surfaces by pathogenic microbes which comprises applying to said surfaces an antiseptic overlay according to any of claims 1 to 6.
8. A method according to claim 7, in which the frequently touched surface is the surface of an object selected from the group of taps, door handles, door push-plates, light switches and toilet flush actuators.