Hospital infections are a serious and growing problem throughout the world due to the ease with which infectious agents can travel in healthcare facilities, Air Solutions proposes an answer.
Despite strenuous efforts on the part of healthcare professionals and hospital authorities, resistant infections are a growing problem. While some of the reported increase is attributed to improved documenting, it is undoubtedly the case that infection control practices are struggling to manage the problem.
Health care acquired infections.
Nosocomial (hospital-acquired) infections are frequently referred to as Health Care Acquired Infections (HCAI) and are often difficult to eradicate, with many being drug resistant. For example, Methicillin-resistant Staphylococcus Aureus (MRSA) is a major problem within many healthcare facilities. The most frequent HCAI’s being Tuberculosis, Meningitis, MRSA, Clostridium Difficile, Chicken Pox, SARS, Influenza including H1N1 and Avian Flu.
Financial implications
While nosocomial infections cause much morbidity and mortality, they also have considerable economic impact on healthcare systems.
These infections affect between 10 and 20 per cent of patients, the infected person subsequently spending up to fifteen days in hospital, instead of the average stay of just four days.
Alarmingly, they are 7.1 times more likely to die.
It is estimated that it costs the healthcare provider an additional $23,000 per HCAI, accumulating to hundreds of millions of dollars per annum.
Transmission route
The term ‘transmission’ refers to the route by which an infectious agent travels to reach a host. Transmission generally occurs by four common routes:
contact
common vehicle
vector-borne
airborne
Direct contact between healthcare workers (HCW’s) and patients is generally considered to be the primary route by which HCAI’s spread between wards. It also includes in-direct contact via light switches, door handles and surfaces. Common vehicle spread includes all transmission which involves inanimate vehicles serving multiple persons, such as food, water and drugs.
Vector borne spread of infection involves the action of an animate third party such as a fly. Malaria is an example of a disease spread by vector which is not a common transmission route for nosocomial infections in Australia.
Airborne transmission refers to those microorganisms which become truly airborne and which are inhaled. A number of important infections are known to spread through the air including tuberculosis, legionnaires disease, aspergillosis and measles. Because of the nature of the transmission route, susceptible people can contract an infection without having direct contact with an infected person.
Many airborne infections arise from infectious particles dispersed in droplet nuclei when infected individuals cough or sneeze. During coughing and sneezing, thousands of droplets are liberated into the air, many of which contain bacteria or viral particles. When expelled the larger droplets fall to the ground, while evaporation of smaller droplets takes place and they rapidly decrease in size to become droplet nuclei. Consequently, most of the droplets produced by a cough or a sneeze will form droplet nuclei many of which contain pathogenic micro-organisms. Droplet nuclei are so small that they settle slowly and in a calm room will take approximately 4.2 hours to fall a distance of 2m and can stay suspended almost indefinitely. Given the long suspension time, particles can carry long distances in convection currents and thus can distribute widely throughout hospital buildings.
There is a large body of evidence supporting the view that staphylococci are frequently disseminated by the aerial route in the clinical environment. Contaminated clothing and bedding colonised patients release staphylococcus aureus into the air when disturbed. During bed making in particular, staphylococci bearing particles are liberated into the air and deposited on surfaces within the environment causing a significant increase in the microbial bioburden.
Although contact spread is considered to be the principle route of transmission for most infections, the contribution of airborne micro-organisms to the spread of infection is much greater than generally currently recognised. This is partly because many airborne micro-organisms remain viable while being non-culturable, with the result that they are not detected and, also because some infections arising from contact transmission involve the airborne transportation of micro-organisms onto inanimate surfaces. There is increasing evidence that nosocomial infections are transmitted by the airborne means and it has been estimated that between 20 to 35 per cent of HCAI’s are caused by this route.
ASHRAE the American Society of Heating, Refrigeration and Air conditioning Engineers produced a position document on airborne infectious diseases in June 2009 detailing the health consequences of exposure to airborne infectious diseases and the implications this knowledge has on the design, installation and operation of heating, ventilation and air conditioning (HVAC) systems.
What is UVGI?
UVGI Systems devices use UVC irradiation at a wavelength of 254 nanometres (nm) to lethally damage airborne microorganisms. This is known as the germicidal irradiation wavelength and the recognised term for this, throughout the world, is UVGI.
How does it work?
UVGI works as a mutagen to bacteria, viruses and other microorganisms on a cellular level, penetrating the cell wall. This disrupts the micro-organism DNA (deoxyrilbonucleic acid), breaking the carbon bond, which causes the death of the cell and/or renders it incapable of multiplying.
Proven results.
UVGI Systems’ original product, was deployed in a long-term (two year) test in four high dependency rooms, used for the treatment/recuperation of immune compromised patients at Basingstoke North Hampshire Hospital, UK.
Two of the high dependency rooms contained UVGI units, offering a dedicated pressurised and sanitised room environment at a significantly lower cost to that of a central plant system. The third room used positive air pressure sanitisation and the fourth room contained a placebo unit.
In controlled laboratory tests, colonies of micro-organisms growing in air samples taken from the rooms using the UVGI technology showed a significant reduction in measured mean colony count, when compared to those taken from the positive air pressure and placebo environments.
Other tests took place at the UK government healthcare agency test house, Porton Down. The performance evaluation of the UVGI purification unit tested air samples in triplicate at four flow rates 600, 930, 1260, 1600m3/h against microbial aerosols of Staphylococcus Epidermis (MRSA); Aspergillus Niger (Aspergillus Fumigatus/Anthrax); Mycobacterium Vaccae (Tuberculosis TB/MDRTB); MS-2 Coliphage (Influenza/SARS Corona virus/E coli).
The results demonstrated, at all four flow rates, an average efficiency greater than 99.9 per cent against the tested bio-aerosols.
Product performance tests were also carried out in partnership with the University of Leeds and Mansfield Pollard and Company. The tests used three microorganisms: Staphylococcus aureus, Aspergillus fumigatus and Bacillus subtillis. Results showed reduced concentrations of these microorganisms by 99.9 per cent.
What makes UVGI Systems unique
UVGI Systems products have been developed from UVGI patented technology and are the result of over ten years intensive research and over £14M investment.
This has produced an air sanitation product range that harnesses maximum light intensity with optimum dwell time, to ensure the best result.
Product range
UVGI Systems’ range of in-duct air sterilisation units has been developed specifically for environments with poor outdoor air quality; servicing areas where patients may have compromised immune systems and for recirculated indoor air systems where there is a need to sanitise specific indoor spaces.
The ceiling mounted device, designed to replace a standard 600mm x 600mm ceiling tile, sterilises indoor air through localised recirculation, specifically for individual rooms and treatment spaces. The directional air-jet system gently agitates all the room air, dissipating areas of high bacterial concentration. The displaced air is drawn back in to the ceiling unit for further UV dosing and recirculated as often as necessary, the treated air being jetted back in to the room minus the harmful microorganisms.
The floor-standing, portable device is used to sterilise air in specific spaces such as waiting-rooms, workspaces or areas with restricted access. This means you can achieve maximum effect for minimal installation costs.
UVGI products are designed to serve any given air duty, within any type of ventilation or air conditioned system and are suitable for both new developments and existing systems.
Energy Saving
In addition UVGI systems can also significantly reduce energy operating costs by 20 per cent in cooling and heating through a reduced fresh air respiratory requirement. UVGI Systems products provide a powerful suite of air sterilisation units. All models have been rigorously laboratory tested under real HVAC conditions for pathogen destruction performance. UVGI Systems have guaranteed and verifiable confirmation of performance ensuring total client confidence in reducing microbial infection. The systems are available in Australia from Air Solutions: www.uvgi.com.