Removal of biofilm from endoscopes

Evaluation of detergent efficiency

Vickery, Karen BVSc, MVSc, PhD
Pajkos, Aniko BSc
Cossart, Yvonne MB BS, BSc (Med), FRCPA

Department of Infectious Diseases, University of Sydney, Sydney, and The Australian Centre for Hepatitis Virology Australia, New South Wales, Australia

Reprint requests: Karen Vickery, PhD, Department of Infectious Diseases and Immunology, University of Sydney, Sydney NSW 2006 Australia.

This research was funded by NH&MRC grant 9937934 and Whiteley Industries Pty Ltd. Aniko Pajkos was in receipt of a APAI Postraguate Industry Award, and Karen Vickery was in receipt of a NH&MRC Australian Postdoctoral Clinical Fellowship. The work was performed in the Department of Infectious Diseases and Immunology, University of Sydney, Sydney, New South Wales 2006, Australia.

AJIC: American Journal of Infection Control 32(3):p 170-176, May 2004.

Background

Biofilm consisting of bacteria enclosed in a matrix of exopolysaccharide (EPS) forms on many medical devices such as catheters and implants. Nosocomial infection is, thus, a newly recognized scenario of biofilm development. Biofilm removal by physical methods such as ultrasound and mechanical cleaning is reasonably effective but difficult to supervise in practice. Chemical methods are often ineffective because of biofilm resistance to biocides. In this study, we compared the efficiency of different detergents used in endoscope reprocessing.

Methods

Escherichia coli biofilm was generated on Teflon and medical grade PVC tubing under low flow conditions. Sections of biofilm covered tubing were washed using test detergents and biofilm removal was assessed by counting remaining adherent bacteria after washing and by scanning electron microscopy to qualitatively assess the amount and nature of the remaining biofilm.

Results

Control tubing developed a multilayered biofilm consisting of >10⁵ bacterial cells/cm². Only Matrix (Whiteley Medical, Sydney, Australia) produced >4 log reduction in viable bacterial numbers. Matrix and Epizyme Rapid (3M Australia, Pymble, Australia) were able to remove up to 75% and 60% of the biofilm, respectively.

Conclusions

Many commonly used enzymatic cleaners fail to reduce the viable bacterial load or remove the bacterial EPS. Cleaners with high enzyme activity, Epizyme Rapid, removed more biofilm but failed to reduce bacterial numbers more than 2 logs. The only cleaner containing no enzymes, Matrix, significantly reduced bacterial viability and residual bacterial EPS.