SPaCE Swab: Point-of-Care Sensor for Simple and Rapid Detection of Acute Wound Infection

Naing Tun Thet, June Mercer-Chalmers, Rosemary J. Greenwood, Amber E.R. Young, Karen Coy, Simon Booth, Anthony Sack, Andrew T.A. Jenkins

Research output: Contribution to journalArticle

Abstract

Wound infection is commonly observed after surgery and trauma but is difficult to diagnose and poorly defined in terms of objective clinical parameters. The assumption that bacteria in a wound correlate with infection is false; all wounds contain microorganisms, but not all wounds are clinically infected. This makes it difficult for clinicians to determine true wound infection, especially in wounds with pathogenic biofilms. If an infection is not properly treated, pathogenic virulence factors, such as rhamnolipids from Pseudomonas aeruginosa, can modulate the host immune response and cause tissue breakdown. Life-threatening sepsis can result if the organisms penetrate deep into host tissue. This communication describes the sensor development for five important clinical microbial pathogens commonly found in wounds: Staphylococcus aureus, P. aeruginosa, Candida albicans/auris, and Enterococcus faecalis (the SPaCE pathogens). The sensor contains liposomes encapsulating a self-quenched fluorescent dye. Toxins, expressed by SPaCE infecting pathogens in early-stage infected wounds, break down the liposomes, triggering dye release, thus changing the sensor color from yellow to green, an indication of infection. Five clinical species of bacteria and fungi, up to 20 strains each (totaling 83), were grown as early-stage biofilms in ex vivo porcine burn wounds. The biofilms were then swabbed, and the swab placed in the liposome suspension. The population density of selected pathogens in a porcine wound biofilm was quantified and correlated with colorimetric response. Over 88% of swabs switched the sensor on (107-108 CFU/swab). A pilot clinical study demonstrated a good correlation between sensor switch-on and early-stage wound infection.

Original languageEnglish
Pages (from-to)2652-2657
Number of pages6
JournalACS Sensors
Volume5
Issue number8
Early online date31 Jul 2020
DOIs
Publication statusPublished - 28 Aug 2020

Keywords

  • bacterial infection
  • biofilm
  • fluorescent dye
  • infection detection
  • liposomes
  • point-of-care
  • wounds

ASJC Scopus subject areas

  • Bioengineering
  • Instrumentation
  • Process Chemistry and Technology
  • Fluid Flow and Transfer Processes

Cite this

Thet, N. T., Mercer-Chalmers, J., Greenwood, R. J., Young, A. E. R., Coy, K., Booth, S., Sack, A., & Jenkins, A. T. A. (2020). SPaCE Swab: Point-of-Care Sensor for Simple and Rapid Detection of Acute Wound Infection. ACS Sensors, 5(8), 2652-2657. https://doi.org/10.1021/acssensors.0c01265