The clothing worn by doctors and nursing staff plays an important role in breaking infection chains in healthcare systems. This has been shown in a study carried out in a hospital in Jerusalem (Israel) which examined the germ contamination of work clothing of 135 doctors and nursing staff. In about 60% of the samples potentially infectious germs were discovered including also antibiotic-resistant germs (MRSA) [Wiener-Well et al., Am J Infect Control, 2011].
Identifying and objectively assessing infection risks
This shows us the highly relevant role played by textiles as potential sources of infection in hospitals. Therefore at the Hohenstein Institute in Bönnigheim (Germany), a new type of germ transmission model has been developed which in a first stage tracks the transmission routes of micro-organisms in a public lavatory. Here scientists observed to what extent there was a spread of bacteria, fungi or viruses from one germ source via the hands of the test persons onto different objects in the room (e.g. lavatory brush, door handle, tap).
Then it was a question of determining to what extent these objects themselves then become a source of infection. The new germ transmission model was used to study for example how many micro organisms are spread from the lavatory brush to the door handle by the hand of a person and what germ dosage is spread further by the hand of the next person opening the door.
The practically-oriented study conducted by the researchers is the first to correlate paths of germ transmission to currently known infectious doses of bacteria, fungi and viruses. Although the number of viable germs decreased as expected with every transmission step from hands to objects in the lavatory, some pathogens were still spread to other test persons in infectious doses through contact with contaminated surfaces.
The new germ transmission model is currently being further developed by scientists at the Hohenstein Institute so that it can also be used for textiles in the healthcare system.
Optimum products for maximum hygiene
For the last few years in order to improve infection prevention, surgical gowns and staff apparel have been antimicrobially treated The effectiveness of such products is examined by specialists at the Hohenstein Institute with the help of standardised procedures based on practical applications. The investigation results of the last few years show that sometimes there are considerable differences in the effectiveness of antimicrobially active textile fibres.
In the procurement or rental of surgical gowns and staff apparel, it is therefore sensible for hygienists to demand independent test certificates. These should prove the antimicrobial effectiveness of the textile raw materials in relation to pathogens such as antibiotic-resistant germs (MRSA, VRE), Salmonella, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus spec. and Acinetobacter spec. This is the only way that indication-specific statements on the antibacterial effectiveness spectrum of staff apparel can be made.
It is also important that the detection of effectiveness of antimicrobially active textile fibres is only carried out through qualitatively secured and validated test systems. Quantitative proof methods should be preferred for testing the level of antibacterial effectiveness. Standardised, internationally recognised detection methods can be modified based on specific indications. A prerequisite for this is an accredited microbiological L2-Laboratory such as the Hohenstein Institute offers.
Nosocomial infections however are not only due to bacteria, often human-pathogenic fungi are the cause of a hospital infection. For diabetics or immuno-suppressed patients, such viral infections (mycoses) can sometimes be fatal. Virus infections, e.g. with the Norovirus, also play an important role in nosocomial infections. The examination of the effectiveness level of antimicrobially active textile fibres in relation to fungi or viruses requires further test systems.
The standard EN 14119 is based for instance on an agar diffusion test which is used for moulds (e. g. Aspergillus niger, Chaetomium globosum u. a.). Suspension tests according to DIN EN ISO 20743 or ISO 22196 can also be modified depending on the application. The list of the test strains stated in the standards has been expanded at the Hohenstein Institute with additional germs, such as the yeast Candida albicans, the pathogen of athlete's foot disease Trychophyton mentagrophytes and the test virus MS2.
More hygiene and wear comfort thanks to cellulose regenerated fibres
Within the framework of the AiF Research Project (AiF-No. 16039 BG) scientists from the Hohenstein Institute, in cooperation with the Thuringia Institute for Textile and Plastics Research (TITK) and the Saxony Textile Research Institute (STFI), have developed rental-suitable antimicrobial workwear based on cellulose regenerated fibres and then classified these in relation to their processing and characteristics of use.
