Underestimation of Staphylococcus aureus (MRSA and MSSA) carriage associated with standard culturing techniques: One third of carriers missed

S T J Tsang; M P McHugh; D Guerendiain; P J Gwynne; J Boyd; A H R W Simpson; T S Walsh; I F Laurenson; K E Templeton

doi:10.1302/2046-3758.71.BJR-2017-0175.R1

Underestimation of Staphylococcus aureus (MRSA and MSSA) carriage associated with standard culturing techniques: One third of carriers missed

Bone Joint Res. 2018 Jan;7(1):79-84. doi: 10.1302/2046-3758.71.BJR-2017-0175.R1.

Authors

S T J Tsang¹, M P McHugh², D Guerendiain², P J Gwynne³, J Boyd⁴, A H R W Simpson⁵, T S Walsh⁶, I F Laurenson², K E Templeton²

Affiliations

¹ Department of Orthopaedic Surgery, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SB, UK and School of Biological Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JR, UK jerry.tsang@ed.ac.uk.
² Department of Medical Microbiology, Royal Infirmary of Edinburgh, 51 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SA, UK.
³ School of Biological Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh EH9 3JR, UK.
⁴ Edinburgh Clinical Trials Unit, University of Edinburgh (Usher Institute), Nine Bioquarter, 9 Little France Road, Edinburgh, EH16 4UX.
⁵ Department of Orthopaedic Surgery, Critical care and Pain Medicine, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SB, UK.
⁶ Critical care and Pain Medicine, Department of Anaesthesia, Critical care and Pain Medicine, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Old Dalkeith Road, Edinburgh EH16 4SB, UK.

PMID: 29330346
PMCID: PMC5805824
DOI: 10.1302/2046-3758.71.BJR-2017-0175.R1

Abstract

Objectives: Nasal carriers of Staphylococcus (S.) aureus (MRSA and MSSA) have an increased risk for healthcare-associated infections. There are currently limited national screening policies for the detection of S. aureus despite the World Health Organization's recommendations. This study aimed to evaluate the diagnostic performance of molecular and culture techniques in S. aureus screening, determine the cause of any discrepancy between the diagnostic techniques, and model the potential effect of different diagnostic techniques on S. aureus detection in orthopaedic patients.

Methods: Paired nasal swabs for polymerase chain reaction (PCR) assay and culture of S. aureus were collected from a study population of 273 orthopaedic outpatients due to undergo joint arthroplasty surgery.

Results: The prevalence of MSSA nasal colonization was found to be between 22.4% to 35.6%. The current standard direct culturing methods for detecting S. aureus significantly underestimated the prevalence (p = 0.005), failing to identify its presence in approximately one-third of patients undergoing joint arthroplasty surgery.

Conclusion: Modelling these results to national surveillance data, it was estimated that approximately 5000 to 8000 S. aureus surgical site infections could be prevented, and approximately $140 million to $950 million (approximately £110 million to £760 million) saved in treatment costs annually in the United States and United Kingdom combined, by using alternative diagnostic methods to direct culture in preoperative S. aureus screening and eradication programmes.Cite this article: S. T. J. Tsang, M. P. McHugh, D. Guerendiain, P. J. Gwynne, J. Boyd, A. H. R. W. Simpson, T. S. Walsh, I. F. Laurenson, K. E. Templeton. Underestimation of Staphylococcus aureus (MRSA and MSSA) carriage associated with standard culturing techniques: One third of carriers missed. Bone Joint Res 2018;7:79-84. DOI: 10.1302/2046-3758.71.BJR-2017-0175.R1.

Keywords: Periprosthetic joint infection; Staphylococcus aureus; Surgical site infection.