A/Prof Karen Vickery1, Sister Dayane Costa1, Dr Anaclara Tipple2, Dr Lillian Lopes2, Dr Honghua Hu1
1Macquarie University, North Ryde, Australia,
2Federal University of Goias, Goias, Brazil
Stainless steel surgical instruments are often re-used and processed until a loss of functionality occurs. We aimed to determine the effect of multiple use and processing cycles on instrument quality over the life of stainless steel surgical instruments.
Cleaned and steam sterilised surgical instruments discarded from Australian hospitals, due to loss of functionality (n=23), were assessed for contaminating protein and bacteria using the bicinchoninic acid protein assay and standard plate culture respectively. The presence of biofilm and instrument damage were visually assessed using scanning electron microscopy (SEM). Instruments were categorised into hinged/serrated, lumened, flexible and irregular surfaced according to their design. New orthopaedic screws that had been processed multiple times were also assessed.
Protein contamination ranged from 24 µg on the new screw to 3,756,046 µg contaminating a forceps. The more complex the instrument design the higher the protein contamination. All samples were culture negative however, biofilm was visually confirmed on 4/8 instruments tested using SEM. SEM also detected soil, holes or black stains on all the instruments.
All instruments examined following loss of functionality, were contaminated with high amounts of protein and microscopy revealed the presence of soil, structural damage and biofilm. Any soil can adversely impact sterilisation, and along with instrument damage impacts the ability to thoroughly clean instruments, highlighting the possible risk in using multiply processed instruments. While less affected, new but multiply processed screws showed soil and biofilm contamination suggesting that screws should be individually packed.
A/Professor Vickery is Scientific Director of the Surgical Infection Research Group, and Vice-Chancellor Innovation Fellow at the Faculty of Medicine and Health Sciences, Macquarie University. She has been at the forefront of research into detecting biofilm associated with medical implants, equipment and environmental surfaces. Her research aims to prevent healthcare associated infections by focusing on both surgical strategies for preventing biofilm infection of medical implants, treating biofilm infections of chronic wounds and strategies that improve instrument and environmental decontamination. She has served on expert advisory committees for the Australian Therapeutic Goods Administration (TGA), GENCA and Standards Australia.