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Developing a real time sensing system to monitor bacteria in wound dressings.

Farrow MJ, Hunter IS, Connolly P - Biosensors (Basel) (2012)

Bottom Line: It is based on impedance sensors that could be placed at the wound-dressing interface and potentially monitor bacterial growth in real time.Impedance was measured using disposable silver-silver chloride electrodes.The main findings were that the impedance profiles obtained by silver-silver chloride sensors in bacterial suspensions could detect the presence of high cell densities.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Strathclyde, Wolfson Centre, Glasgow, G4 0NW, UK. malcolm.farrow@strath.ac.uk.

ABSTRACT
Infection control is a key aspect of wound management strategies. Infection results in chemical imbalances and inflammation in the wound and may lead to prolonged healing times and degradation of the wound surface. Frequent changing of wound dressings may result in damage to healing tissues and an increased risk of infection. This paper presents the first results from a monitoring system that is being developed to detect presence and growth of bacteria in real time. It is based on impedance sensors that could be placed at the wound-dressing interface and potentially monitor bacterial growth in real time. As wounds can produce large volumes of exudate, the initial system reported here was developed to test for the presence of bacteria in suspension. Impedance was measured using disposable silver-silver chloride electrodes. The bacteria Staphylococcus aureus were chosen for the study as a species commonly isolated from wounds. The growth of bacteria was confirmed by plate counting methods and the impedance data were analysed for discernible differences in the impedance profiles to distinguish the absence and/or presence of bacteria. The main findings were that the impedance profiles obtained by silver-silver chloride sensors in bacterial suspensions could detect the presence of high cell densities. However, the presence of the silver-silver chloride electrodes tended to inhibit the growth of bacteria. These results indicate that there is potential to create a real time infection monitor for wounds based upon impedance sensing.

No MeSH data available.


Related in: MedlinePlus

The final numbers of RN4220, SA081 and SA082 with Ag-AgCl sensors after 24 h culturing from different starting densities. Three replicate cultures are shown for each of the three strains of Staphylococcus aureus at each starting density. Sample 1(); Sample 2(); Sample 3(); Mean control ().
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biosensors-02-00171-f007: The final numbers of RN4220, SA081 and SA082 with Ag-AgCl sensors after 24 h culturing from different starting densities. Three replicate cultures are shown for each of the three strains of Staphylococcus aureus at each starting density. Sample 1(); Sample 2(); Sample 3(); Mean control ().

Mentions: To investigate the effect of the inoculation density on the bacterial growth in the presence of Ag-AgCl sensors, the presence of which will introduce some silver ions into the culture system, the three strains of Staphylococcus aureus were grown from four starting cell densities between 1 × 102 and 1 × 105 CFU∙mL−1 without the application of voltage for impedance measurements (Figure 7). This would also show whether the clinical strains were more robust in the presence of the AgCl than RN4220. The final cell densities with sensors indicated that, below a critical starting cell density, it was not guaranteed that the final cell densities would reach 1 × 109 CFU∙mL−1 (expected level based on the RN4220 controls without sensors). For RN4220, this critical starting density was approximately 1,000 CFU∙mL−1 while, for SA081 and SA082, the density was approximately 1 × 105 CFU∙mL−1. This provides further evidence that the presence of the Ag-AgCl sensors has an influence on bacterial growth rates and that the two clinical strains may not be as resistant to AgCl as the RN4220 strain.


Developing a real time sensing system to monitor bacteria in wound dressings.

Farrow MJ, Hunter IS, Connolly P - Biosensors (Basel) (2012)

The final numbers of RN4220, SA081 and SA082 with Ag-AgCl sensors after 24 h culturing from different starting densities. Three replicate cultures are shown for each of the three strains of Staphylococcus aureus at each starting density. Sample 1(); Sample 2(); Sample 3(); Mean control ().
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263571&req=5

biosensors-02-00171-f007: The final numbers of RN4220, SA081 and SA082 with Ag-AgCl sensors after 24 h culturing from different starting densities. Three replicate cultures are shown for each of the three strains of Staphylococcus aureus at each starting density. Sample 1(); Sample 2(); Sample 3(); Mean control ().
Mentions: To investigate the effect of the inoculation density on the bacterial growth in the presence of Ag-AgCl sensors, the presence of which will introduce some silver ions into the culture system, the three strains of Staphylococcus aureus were grown from four starting cell densities between 1 × 102 and 1 × 105 CFU∙mL−1 without the application of voltage for impedance measurements (Figure 7). This would also show whether the clinical strains were more robust in the presence of the AgCl than RN4220. The final cell densities with sensors indicated that, below a critical starting cell density, it was not guaranteed that the final cell densities would reach 1 × 109 CFU∙mL−1 (expected level based on the RN4220 controls without sensors). For RN4220, this critical starting density was approximately 1,000 CFU∙mL−1 while, for SA081 and SA082, the density was approximately 1 × 105 CFU∙mL−1. This provides further evidence that the presence of the Ag-AgCl sensors has an influence on bacterial growth rates and that the two clinical strains may not be as resistant to AgCl as the RN4220 strain.

Bottom Line: It is based on impedance sensors that could be placed at the wound-dressing interface and potentially monitor bacterial growth in real time.Impedance was measured using disposable silver-silver chloride electrodes.The main findings were that the impedance profiles obtained by silver-silver chloride sensors in bacterial suspensions could detect the presence of high cell densities.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Strathclyde, Wolfson Centre, Glasgow, G4 0NW, UK. malcolm.farrow@strath.ac.uk.

ABSTRACT
Infection control is a key aspect of wound management strategies. Infection results in chemical imbalances and inflammation in the wound and may lead to prolonged healing times and degradation of the wound surface. Frequent changing of wound dressings may result in damage to healing tissues and an increased risk of infection. This paper presents the first results from a monitoring system that is being developed to detect presence and growth of bacteria in real time. It is based on impedance sensors that could be placed at the wound-dressing interface and potentially monitor bacterial growth in real time. As wounds can produce large volumes of exudate, the initial system reported here was developed to test for the presence of bacteria in suspension. Impedance was measured using disposable silver-silver chloride electrodes. The bacteria Staphylococcus aureus were chosen for the study as a species commonly isolated from wounds. The growth of bacteria was confirmed by plate counting methods and the impedance data were analysed for discernible differences in the impedance profiles to distinguish the absence and/or presence of bacteria. The main findings were that the impedance profiles obtained by silver-silver chloride sensors in bacterial suspensions could detect the presence of high cell densities. However, the presence of the silver-silver chloride electrodes tended to inhibit the growth of bacteria. These results indicate that there is potential to create a real time infection monitor for wounds based upon impedance sensing.

No MeSH data available.


Related in: MedlinePlus