The increased killing of biofilms in vitro by combining topical silver dressings with topical negative pressure in chronic wounds

Valente, Pedro Miguel; Deva, Anand K.; Ngo, Quan; Vickery, Karen

doi:10.1111/iwj.12248

Cited by 26 publications

(14 citation statements)

References 31 publications

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“…However, it should be noted that this increase was measured at a depth of 1 cm under the wound surface Fig. *p \ 0.05, **p \ 0.01 and was presumably caused by the macrodeformation of tissue and the direct contact between foam struts and wound beds (Kairinos et al 2009;Ngo et al 2012;Valente et al 2014). Negative pressure significantly inhibited the transcription of biofilm and virulence-related genes in S. aureus relative to the control.…”

Section: Discussionmentioning

confidence: 93%

“…Interestingly, there are some previous studies concerning the compression effect of NPWT foam on wound beds and established mature biofilms (Ngo et al 2012;Valente et al 2014). Other in vivo studies further investigated the changes of extracellular pressure in response to NPWT, showing a seemingly paradoxical increase in tissue pressure within wound beds (Huang et al 2014;Kairinos et al 2009).…”

Section: Discussionmentioning

confidence: 99%

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Effect of negative pressure on growth, secretion and biofilm formation of Staphylococcus aureus

Wang

Yin

et al. 2015

Antonie van Leeuwenhoek

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Negative pressure wound therapy (NPWT) has gained popularity in the management of contaminated wounds as an effective physical therapy, although its influence on the bacteria in the wounds remains unclear. In this study, we attempted to explore the effect of negative pressure conditions on Staphylococcus aureus, the most frequently isolated pathogen during wound infection. S. aureus was cultured in Luria-Bertani medium at subatmospheric pressure of -125 mmHg for 24 h, with the bacteria grown at ambient pressure as the control. The application of negative pressure was found to slow down the growth rate and inhibit biofilm development of S. aureus, which was confirmed by static biofilm assays. Furthermore, decreases in the total amount of virulence factors and biofilm components were observed, including α-hemolysin, extracellular adherence protein, polysaccharide intercellular adhesin and extracellular DNA. With quantitative RT-PCR analysis, we also revealed a significant inhibition in the transcription of virulence and regulatory genes related to wound infections and bacterial biofilms. Together, these findings indicated that negative pressure could inhibit the growth, virulence and biofilm formation of S. aureus. A topical subatmospheric pressure condition, such as NPWT, may be a potential antivirulence and antibiofilm strategy in the field of wound care.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Effect of negative pressure on growth, secretion and biofilm formation of Staphylococcus aureus

Wang

Yin

et al. 2015

Antonie van Leeuwenhoek

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“…In an effort to seek safe and effective wound care modalities, early application of NPWT has been widely acknowledged for its considerable efficacy and low incidence of biofilm-associated infections ( 32 – 38 ). However, despite an increasing number of studies investigating this type of therapy, the potential role of NPWT in biofilm prevention has yet to be elucidated ( 37 – 44 ). The present study examined and evaluated the effect of NPWT on biofilm prevention when initiated rapidly following wound contamination.…”

Section: Discussionmentioning

confidence: 99%

“…However, investigations into the role of NPWT in biofilm formation remain limited. Despite individual studies suggesting its compression effect on established mature biofilms in vitro ( 42 – 44 ), the efficacy of NPWT on biofilm prevention remains unclear, particularly in vivo .…”

Section: Introductionmentioning

confidence: 99%

Early application of negative pressure wound therapy to acute wounds contaminated with Staphylococcus aureus: An effective approach to preventing biofilm formation

Zhang

Han

et al. 2016

Experimental and Therapeutic Medicine

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Negative pressure wound therapy (NPWT) has been demonstrated to be effective at preventing biofilm-associated infections; however, its role in biofilm prevention is unknown. The present study evaluated the effect of NPWT on biofilm prevention when rapidly initiated following wound contamination. Full-thickness dermal wounds (8 mm) were created in rabbit ears and inoculated with green fluorescent protein-labeled Staphylococcus aureus (S. aureus). At 6 h following inoculation, continuous NPWT at −125 mmHg was initiated, with the wounds on the contralateral ear left untreated in order to serve as self-controls. S. aureus rapidly formed mature biofilms in the wound beds post-inoculation, with a persistent bacterial burden of ~105−107 colony-forming units (CFUs)/wound and impaired wound healing. Compared with the untreated group, NPWT resulted in a significant reduction in biofilm matrix, which was verified by scanning electron microscopy and epifluorescence. A reduction in bacterial counts followed (P<0.05) with ~103 CFUs/wound on postoperative day 13 and improvement in all healing parameters (P<0.05) relative to control wounds. The results of the present investigation suggest that NPWT is an effective strategy to impeding the formation of S. aureus wound biofilms when initiated rapidly following bacterial contamination. The early application of NPWT, aimed at biofilm prevention, may improve wound care.

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“…Accordingly, Ag can address a timely public health issue, as chronic wounds represent a substantial financial and medical burden to the health care system. One of the hallmarks of a chronic wound is the presence of a biofilm, a factor that complicates wound healing and is hypothesized to be the fulcrum between the acute-to-chronic-wound transition (6,(9)(10)(11)(12)(13)(14)(15). Also, bacterial biofilms contaminate implanted medical devices (16) and exhibit high-level resistance to conventional antibiotics (17)(18)(19)(20)(21)(22)(23).…”

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confidence: 99%

Silver Oxynitrate, an Unexplored Silver Compound with Antimicrobial and Antibiofilm Activity

Lemire

Kalan

Bradu

et al. 2015

Antimicrob Agents Chemother

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bHistorically it has been accepted, and recent research has established, that silver (Ag) is an efficacious antimicrobial agent. A dwindling pipeline of new antibiotics, combined with an increase in the number of antibiotic-resistant infections, is bringing Ag to the fore as a therapeutic compound to treat infectious diseases. Currently, many formulations of Ag are being deployed for commercial and medical purposes, with various degrees of effectiveness at killing microbial cells. H istory has demonstrated that silver (Ag) is an efficacious antimicrobial agent, finding utility as an antiquated preservative for food and water (1, 2). Currently, Ͼ100 Ag-containing medical devices have been approved for use by the FDA (http: //www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn .cfm), and there is mounting evidence that Ag may be effective for preventing the spread of infectious disease (1,3,4). Although the toxicological profile of orally administered Ag remains to be resolved, topical application for the treatment of chronic wounds remains promising (5-8). Accordingly, Ag can address a timely public health issue, as chronic wounds represent a substantial financial and medical burden to the health care system. One of the hallmarks of a chronic wound is the presence of a biofilm, a factor that complicates wound healing and is hypothesized to be the fulcrum between the acute-to-chronic-wound transition (6, 9-15). Also, bacterial biofilms contaminate implanted medical devices (16) and exhibit high-level resistance to conventional antibiotics (17-23). New antibiofilm agents are thus desperately needed in medicine.Recently, researchers have demonstrated that Ag formulations also have potential as antibiofilm agents; these formulations include silver sulfadiazine (AgSD) (24), Ag nanoparticles (AgNPs) (25, 26), and silver nitrate (AgNO 3 ) (27). Currently, the wound care industry is replete with Ag-based ointments and wound dressings with claimed efficacy at reducing bacterial bioburden (7,(28)(29)(30)(31)(32). However, only a few antibiofilm products exist. There are numerous reasons why this is so: (i) current standardized, antimicrobial testing methods focus on bacteria in their planktonic state and not as biofilms (33, 34); (ii) biofilms are characteristically more tolerant to metal poisoning (35-38); and (iii) the detailed mechanism of action for the toxicity of Ag to biofilms remains to be fully described (1).The antimicrobial activity of Ag is intrinsically dependent on the formation of the Ag 1ϩ ion (7, 39). Briefly, Ag 1ϩ , a Lewis soft acid, poisons the microbial cell by binding to reduced thiols (SH), impairing membrane function (1), and disrupting ironsulfur clusters (40). That being said, the antimicrobial efficacy of higher oxidation states of Ag, Ag 2ϩ and Ag 3ϩ , has not been given adequate consideration, mainly due to instability in solution. A promising resolution to the instability of higher oxidation states of Ag is silver oxysalts, for example, Ag(Ag 3 O 4 ) 2 X, the most stable of which is coordina...

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The increased killing of biofilms in vitro by combining topical silver dressings with topical negative pressure in chronic wounds

Cited by 26 publications

References 31 publications

Effect of negative pressure on growth, secretion and biofilm formation of Staphylococcus aureus

Effect of negative pressure on growth, secretion and biofilm formation of Staphylococcus aureus

Early application of negative pressure wound therapy to acute wounds contaminated with Staphylococcus aureus: An effective approach to preventing biofilm formation

Silver Oxynitrate, an Unexplored Silver Compound with Antimicrobial and Antibiofilm Activity

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