Minimising cross contamination with liquid and semi-solid products
Mike Waring1 Sofia Hussain2 and Anders Bared3
1Devicemark Ltd, Greasby, UK, CH49 1SE 2MSL Bury, UK, BL9 5NB, 3Aurena Laboratories AB, 653 50 Karlstad, Sweden
Avoiding cross contamination in the clinical setting is an objective that we all hope to achieve. The delivery of multiple use liquid and semi-solid preparations can often be the cause of such contamination. This study examined two products both filled into a bag on valve delivery system, an aqueous sterile irrigation spray and a protective barrier/moisturiser spray.
Sterile Irrigation Spray
The sterility of a saline spray during use was assessed by storing ten samples at 37ᵒC and spraying 3 times a day on to a forearm at a distance of 10cm. TVC testing was carried out on days 1, 3, 7, 10 and 14
Less than 10 cfu/ml were measured throughout the 14-day test period when the instructions for use were followed directly. Normal skin flora was observed on the forearm arm being sprayed
Protective barrier/moisturiser spray
To assess the sterility of the protective barrier spray during use, the sample nozzle was inoculated with low levels of Methicillin-Resistant Staphylococcus aureus (MRSA) to simulate contamination from an outside source. TVC testing was the carried out at days 0, 3 and 5
The barrier/moisturiser spray when contaminated with MRSA at day 0 was shown to have 7.0x104 cfu/ml. On days 3 and 5 however, less than 10 cfu/ml were measured from the spray.
As multiple use products they both appear to offer some protection from bacterial growth in use, be it caused by splash back (sterile irrigation spray) or by providing an environment that does not support growth in the product flow path (protective barrier/moisturiser spray). Ideally multiple use products should be for single patient use however ,these findings suggest that should the products be transferred from one patient to another then cross contamination can be minimised
A sealed system such as the bag on valve container for wound irrigation and the spray barrier/ moisturiser for protecting skin at risk may offer significant advantages compared to jars and tubes in reducing cross contamination in the clinical environment. As the propellant (nitrogen) is separated from the product the physical properties of the product are relatively unchanged.