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Reduction of a multidrug-resistant pathogen and associated virulence factors in a burn wound infection model: further understanding of the effectiveness of a hydroconductive dressing.

Carney BC, Ortiz RT, Bullock RM, Prindeze NJ, Moffatt LT, Robson MC, Shupp JW - Eplasty (2014)

Bottom Line: Drawtex's ability to remove pathogens and associated virulence factors has been demonstrated in vitro.The hydroconductive dressing provided a significant reduction in pathogen and virulence factors compared to a control dressing.As a result of clearance of virulence factors from the wound bed, a requisite alteration in host innate immune response was observed.

View Article: PubMed Central - PubMed

Affiliation: Firefighters' Burn and Surgical Research Laboratory, MedStar Health Research Institute, Washington, DC.

ABSTRACT

Objective: Drawtex's ability to remove pathogens and associated virulence factors has been demonstrated in vitro. A model of burn wound infection was used to characterize the in vivo impact of this dressing on infection and wound healing.

Methods: Paired burn wounds were created on the dorsum of Sprague Dawley rats and were inoculated with methicillin-resistant Staphylococcus aureus (MRSA). Animals were divided into 2 groups, half with wounds that received experimental dressing and the remaining half with control dressing-treated wounds. Dressings remained in place through 3, 6, 9, or 14 days after injury, and methicillin-resistant S aureus and virulence factors were quantified. Laser Doppler imaging was used to examine wound perfusion, and local host immune response was assessed through the quantification of mRNA expression.

Results: By day 3, less methicillin-resistant S aureus was measured in wounds treated with experimental-dressing compared to control-dressing wounds. Quantities remained lower in the experimental group through day 14 (P < .001). More methicillin-resistant S aureus was quantified in the experimental dressing itself than in control dressing at all time points (P < .05). Experimental dressing-treated wounds contained less toxic shock syndrome toxin 1 and Panton-Valentine leukocidin than controls (P < .01) on days 6, 9, and 14. Induction of toll-like receptor 2, NOD-like receptor family, pyrin domain containing 3, and interleukin 6 was significantly lower in experimental-dressing treated wounds than in controls on days 6 and 9 (P < .05).

Conclusions: The hydroconductive dressing provided a significant reduction in pathogen and virulence factors compared to a control dressing. As a result of clearance of virulence factors from the wound bed, a requisite alteration in host innate immune response was observed.

No MeSH data available.


Related in: MedlinePlus

Colony forming units of methicillin-resistant Staphylococcus aureus (MRSA) per gram of wound (A) or dressing (B) biopsies quantified at 2, 3, 6, 9, or 14 days after burn injury. Statistically significant differences (*) in MRSA levels between experimental and control dressing samples (B) or the corresponding treated wounds (A) at each time point were assessed using multiple t tests with a Holm-Sidak correction for multiple tests (P < .05). Data are shown as means with standard deviations.
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Figure 1: Colony forming units of methicillin-resistant Staphylococcus aureus (MRSA) per gram of wound (A) or dressing (B) biopsies quantified at 2, 3, 6, 9, or 14 days after burn injury. Statistically significant differences (*) in MRSA levels between experimental and control dressing samples (B) or the corresponding treated wounds (A) at each time point were assessed using multiple t tests with a Holm-Sidak correction for multiple tests (P < .05). Data are shown as means with standard deviations.

Mentions: By postburn day 3, significantly less (P < .05) MRSA was measured in wounds treated with experimental dressing than in those treated with control dressing. Quantities remained lower in the experimental group on day 6 (P < .001) and were further reduced on days 9 (P < .001) and 14 (Fig 1A). Correspondingly, more MRSA was quantified in the experimental dressing than in control dressing at all time points (P < .05), with levels increasing in the experimental dressing through day 14 (Fig 1B). Wound biopsy images obtained using immunofluorescence show differential S aureus staining in wounds treated with experimental versus control dressings (Fig 2). Experimental dressing-treated wounds also contained significantly less TSST-1 (Fig 3A) and PVL (Fig 3C) than controls (P < .01) on days 6, 9, and 14, while the experimental dressing itself contained more TSST-1 and PVL on days 6, 9, and 14 than the control dressing (P < .001; Figs 3B and 3D). Virulence factor levels were not significantly different between experimental and control groups on day 3 in the wounds or dressings. Low levels of virulence factors were measured in wounds from both groups as early as postburn day 2, only 24 hours after inoculation began (Figs 3A and 3C). Immunofluorescent wound biopsy images show correlative differential TSST-1 staining in wounds treated with experimental versus control dressings (Fig 4).


Reduction of a multidrug-resistant pathogen and associated virulence factors in a burn wound infection model: further understanding of the effectiveness of a hydroconductive dressing.

Carney BC, Ortiz RT, Bullock RM, Prindeze NJ, Moffatt LT, Robson MC, Shupp JW - Eplasty (2014)

Colony forming units of methicillin-resistant Staphylococcus aureus (MRSA) per gram of wound (A) or dressing (B) biopsies quantified at 2, 3, 6, 9, or 14 days after burn injury. Statistically significant differences (*) in MRSA levels between experimental and control dressing samples (B) or the corresponding treated wounds (A) at each time point were assessed using multiple t tests with a Holm-Sidak correction for multiple tests (P < .05). Data are shown as means with standard deviations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4264520&req=5

Figure 1: Colony forming units of methicillin-resistant Staphylococcus aureus (MRSA) per gram of wound (A) or dressing (B) biopsies quantified at 2, 3, 6, 9, or 14 days after burn injury. Statistically significant differences (*) in MRSA levels between experimental and control dressing samples (B) or the corresponding treated wounds (A) at each time point were assessed using multiple t tests with a Holm-Sidak correction for multiple tests (P < .05). Data are shown as means with standard deviations.
Mentions: By postburn day 3, significantly less (P < .05) MRSA was measured in wounds treated with experimental dressing than in those treated with control dressing. Quantities remained lower in the experimental group on day 6 (P < .001) and were further reduced on days 9 (P < .001) and 14 (Fig 1A). Correspondingly, more MRSA was quantified in the experimental dressing than in control dressing at all time points (P < .05), with levels increasing in the experimental dressing through day 14 (Fig 1B). Wound biopsy images obtained using immunofluorescence show differential S aureus staining in wounds treated with experimental versus control dressings (Fig 2). Experimental dressing-treated wounds also contained significantly less TSST-1 (Fig 3A) and PVL (Fig 3C) than controls (P < .01) on days 6, 9, and 14, while the experimental dressing itself contained more TSST-1 and PVL on days 6, 9, and 14 than the control dressing (P < .001; Figs 3B and 3D). Virulence factor levels were not significantly different between experimental and control groups on day 3 in the wounds or dressings. Low levels of virulence factors were measured in wounds from both groups as early as postburn day 2, only 24 hours after inoculation began (Figs 3A and 3C). Immunofluorescent wound biopsy images show correlative differential TSST-1 staining in wounds treated with experimental versus control dressings (Fig 4).

Bottom Line: Drawtex's ability to remove pathogens and associated virulence factors has been demonstrated in vitro.The hydroconductive dressing provided a significant reduction in pathogen and virulence factors compared to a control dressing.As a result of clearance of virulence factors from the wound bed, a requisite alteration in host innate immune response was observed.

View Article: PubMed Central - PubMed

Affiliation: Firefighters' Burn and Surgical Research Laboratory, MedStar Health Research Institute, Washington, DC.

ABSTRACT

Objective: Drawtex's ability to remove pathogens and associated virulence factors has been demonstrated in vitro. A model of burn wound infection was used to characterize the in vivo impact of this dressing on infection and wound healing.

Methods: Paired burn wounds were created on the dorsum of Sprague Dawley rats and were inoculated with methicillin-resistant Staphylococcus aureus (MRSA). Animals were divided into 2 groups, half with wounds that received experimental dressing and the remaining half with control dressing-treated wounds. Dressings remained in place through 3, 6, 9, or 14 days after injury, and methicillin-resistant S aureus and virulence factors were quantified. Laser Doppler imaging was used to examine wound perfusion, and local host immune response was assessed through the quantification of mRNA expression.

Results: By day 3, less methicillin-resistant S aureus was measured in wounds treated with experimental-dressing compared to control-dressing wounds. Quantities remained lower in the experimental group through day 14 (P < .001). More methicillin-resistant S aureus was quantified in the experimental dressing itself than in control dressing at all time points (P < .05). Experimental dressing-treated wounds contained less toxic shock syndrome toxin 1 and Panton-Valentine leukocidin than controls (P < .01) on days 6, 9, and 14. Induction of toll-like receptor 2, NOD-like receptor family, pyrin domain containing 3, and interleukin 6 was significantly lower in experimental-dressing treated wounds than in controls on days 6 and 9 (P < .05).

Conclusions: The hydroconductive dressing provided a significant reduction in pathogen and virulence factors compared to a control dressing. As a result of clearance of virulence factors from the wound bed, a requisite alteration in host innate immune response was observed.

No MeSH data available.


Related in: MedlinePlus