Static change and hospital infections

Nosocomial infection is a major problem in healthcare facilities around the world. In the UK it is estimated that at least 100,000 hospital-acquired infections occur each year, costing the NHS in England alone approximately £1 billion per annum. In air, the electric charge carried by a bacterium consists of two components: its own natural charge, which can be high and the charge imposed on it by the dispersion process. In practice, bacteria usually become airborne as a result of frictional processes (e.g. by sneezing, coughing or the shedding of skin squamae) and this may be an important feature to their high charge state in air. Airborne bacteria can carry up to 10,000 electric charges.

In an electrostatic field, such bacteria will be subject to a drift velocity according to their electrical mobility and in their high charge state they could move quickly to deposit onto surfaces. Plastic materials which are widely used in the hospital environment are prone to the accumulation of electrostatic charge on their surfaces. For example, a nurse wearing a plastic apron with static charge will set up an electric field between nurse and patient and may facilitate the transfer of micro-organisms in air either directly onto the patient or indirectly through contact with the patient or with the bedclothes. Aprons could be made with conducting plastic which would prevent the build-up of static charge.

We have completed a study which compares the electrostatic properties of five different types of nurse's disposable aprons. These aprons have different types and amounts of antistatic agents added to the polythene mixture. Results showed that two of the five types were, in fact, antistatic and one apron in particular exhibited a 38% reduction of bacteria attracted onto its surface compared with the white plastic aprons currently in use.

As a result of this study, the new 'STATIC FREE' aprons will be available to the NHS from April 2006

Antistatic nurses’ aprons may contribute to a reduction of hospital infection in isolation wards
Allen JE and Henshaw DL, 2006
(PDF file: 130KB)

Static electric fields as a mediator of nosocomial infection
Janet E. Allen. Presented at the Second International Conference on the Quality of the Indoor Environment in Hospitals at the Institute of Clinical and Experimental Medicine (IKEM), Prague, 6-7 October 2005
(PDF file: 1.4MB)

Static electric fields as a mediator of hospital infection
Allen JE, Close JJ and Henshaw DL, 2006
Indoor and Built Environment, 15, 1, 49-52

Static electric fields as a mechanism of nosocomial infection
Janet E Allen. Presented at a conference on Electric fields and discharges for microbiology and health care applications.
Organised by the Electrostatics Group of the Institute of Physics, London, 19th May 2005

Hospital infections: bio-aerosols and static charge.
JE Allen. Conference on Elecrified Aerosols in the environment Institute of Physics, London. 9th July 2003

Static electric charge may contribute to infections in bone marrow transplant wards.
J E Allen, D L Henshaw, H Wynne, F Ross and A Oakhill, 2003.
Journal of Hospital Infection, 54(1), 80-81.

Bio-aerosols, static charge and hospital infections. INVITED PAPER
JE Allen, DL Henshaw, H Wynne, F Ross and A. Oakhill, 2002.
IASTA Bulletin, 14, No.1, 8-11. Indian Aerosol Science and Technology Association. Environmental Assessment Division, BARC, Mumbai 400 085, India

Biological aerosols, static charge and hospital infections.
J E Allen, D L Henshaw, H Wynne, F Ross and A Oakhill, 2001.
Contribution to The Aerosol Society’s 12th Annual Conference and AGM, 18–19 June, University of Bath. ISBN 0 9529777 6 1

Bone marrow transplant wards: movement of airborne bacteria in the presence of electric fields