S. aureus is transferred through the skin via injection, even after cleaning
New research in Scientific Reports shows that standard disinfection procedures may not be enough to prevent S. aureus contamination with injection.
- Skin colonised by S. aureus contaminates needles upon injection
- Standard antimicrobial preparations do not prevent transfer of S. aureus
- Other factors such as the type of injection and the needle diameter also affect contamination
Researchers from Maryland in the US have raised some important questions about how we perform injections in hospitals. From a series of experiments using porcine skin and a synthetic skin made of silicone, the authors claim that standard disinfection methods may not be enough to prevent contamination of injection sites in the hospital. The researchers recommend that longer contact times with standard antimicrobials may be enough to prevent contamination by S. aureus. They also showed that thicker needles and deeper injections increase the risk of contamination which could give medical staff new parameters for monitoring patients.
While surgical site preparation has been extensively studied, there is little information about resistance of skin microbiota in the biofilm form to antimicrobial decontamination, and there are no quantitative models to study how biofilm might be transferred into sterile tissue/implant materials during injections for joint spine and tendon, aspiration biopsies and dermal fillers (DF). In this work, we develop two in vitro models to simulate the process of skin preparation and DF injection using pig skin and SimSkin (silicone) materials, respectively. Using the pig skin model, we tested three of the most common skin preparation wipes (alcohol, chlorhexidine and povidone iodine) and found that during wiping they reduced the biofilm bacterial burden of S. aureus (CFU cm−2) by three logs with no statistically significant differences between wipes. Using the SimSkin model, we found that transfer of viable bacteria increased with needle diameter for 30G, 25G and 18G needles. Transfer incidence decreased as injection depth was increased from 1 mm to 3 mm. Serial puncture and linear threading injection styles had similar transfer incidence, whereas fanning significantly increased transfer incidence. The results show that contamination of DF during injection is a risk that can be reduced by modifying skin prep and injection practices.
Injections through skin colonized with Staphylococcus aureus biofilm introduce contamination despite standard antimicrobial preparation procedures. Yi Wang, Valery Leng, Viraj Patel & K. Scott Phillips.
Scientific Reports 7, Article number: 45070 (2017). doi:10.1038/srep45070