A perfect dressing for infection prevention
BIOGUARD® Barrier Dressings, with their patented active component and patented method of fabrication, are designed specifically for prophylactic infection prevention in wounds.
Due to a patented manufacturing process, the active component within BIOGUARD® Barrier Dressings is intrinsically bound to the base substrate – it does not leach away from the dressing. This is important as leaching antimicrobials can be toxic to good cells. BIOGUARD® is the only non-leaching dressing of its kind.
Due to the active components’ relatively large size, and also due to the non-leaching attributes of the dressing, bacteria can not develop resistance to BIOGUARD® dressings. This is a vital benefit of a dressing being considered for prophylactic widespread usage.
BIOGUARD® Barrier Dressings offer clinicians a truly unique and ideal line of barrier dressings that can play an important role in a facility’s overall infection protection program.
Wound infection, by the numbers:
2.7%: The percentage of surgical interventions complicated by a Surgical Site Infection (SSI) (over 500,000 in the US annually)
2 out of 3: Surgical treatments of skin and debridement of wound infections are 2 out of 3 of the top procedures associated with the treatment of MRSA infections
2005: The year deaths attributable to MRSA began to exceed deaths attributable to HIV/Aids in the US
$25,546: The average incremental cost of an SSI
October 1, 2008: The day Medicare stopped paying for certain catheter associated infections and surgical site infections
8000 CFUs wound bacteria per cubic meter of air: is released with each gauze dressing change increasing potential of cross contamination
Three: The number of key characteristics wound care physicians consistently describe as the ideal dressing for prophylaxis use:
+ Non-toxic – must not disrupt wound healing.
+ Elimination of antimicrobial resistance – with widespread usage on large numbers of wounds, this is a “must-have.”
+ Cost-effective and easy to use – Transitions easily into existing care protocols.
BIOGUARD® Barrier Dressings have been proven to prevent bacterial penetration and inhibit growth within wound dressings. BIOGUARD® provides a barrier to bacterial penetration, and results in >5-log (99.999%) kill of a broad spectrum of microbes – including antibiotic resistant organisms. The active component within BIOGUARD® is a cationic biocide called PolyDADMAC (poly diallyl dimethyl ammonium chloride). PolyDADMAC shares the same compound class as PHMB (poly hexadine methyl biguanide), with two key differences:
It is intrinsically bound to the base dressing substrate, unlike PHMB, which leaches away from the dressing.
It is significantly larger than PHMB, with a molecular weight of 200,000–250,000 g/mol (PHMB molecular weight = 2,000–4,000 g/mol).*
Why does leaching matter?
For wounds that are either critically colonized or infected, bacterial control—even at the expense of some good cells—is paramount. For antimicrobials such as silver dressings, this is standard course of action. That’s why these dressings are generally limited to critically colonized/infected situations for a maximum duration of 4 weeks.
For wounds that are sterile, contaminated, or colonized, the main goal is wound healing (while avoiding critical colonization or infection). For these wound types, only dressings that are non-toxic to healthy cells should be considered. (See Fig.1)
Also when considering dressings as prophylaxis and as an important part of an infection prevention program, only dressings that consistently demonstrate no chance of causing antimicrobial resistance should be considered. Leaching leads to sub-minimum inhibitory concentrations, which can lead to resistant strain formation.
A Short Course on Zone of Inhibition (ZOI)
BIOGUARD® shows no zone of inhibition, and direct contact testing with L929 fibroblast cell line shows normal healthy growing cells. This market leading silver dressing shows a zone of inhibition where the chemical leaches out of the dressing: the effect of leached silver is shown in the direct contact assay by malformed and depopulated cells.
What about size?
Most causes of antimicrobial resistance occur when the active component enters into the cell of the pathogen. With a molecular weight up to 100x larger than PHMB, PolyDADMAC simply won’t fit through holes in the damaged cell walls of microbes.
In this standard antimicrobial resistance assay (See Fig.2), consistent exposure to PolyDADMAC – for a prolonged period of time – showed no resistance to the biocide treated substrate. Throughout a 10-round step-by-step adaptation training test, bacterial cells were exposed to PolyDADMAC. From each round only bacterial survivors were propagated into a new inoculum. Even after continued exposure to the biocide (10X), no resistance was formed.
Direct Exposure to the Treated Surface
Method of Action
The active in BIOGUARD® Barrier Dressings—PolyDADMAC—is an advanced cationic biocide polymer with a high charge density and high molecular weight, permanently bound to the barrier dressing. Cationic biocides include surface active quaternary ammonium compounds, or “Quats”. Quats attract bacterial cells and bind rapidly to the cellular envelope to displace otherwise stable calcium ions and physically disrupts the cell wall structures (See Fig.3). Cationic biocides cause the membrane to fragment, leading to generalized cellular leakage. The higher the charge density, the more likely the Quat’s effects will not be diluted in high levels of exudate or other bodily uids.
Since the active agent is permanently bound to the barrier dressing, there is no leaching and no depletion of the biocide reservoir. This means the active agent within the dressing can never fall below the minimum inhibitory concentration (MIC). Additionally, bacteria cannot develop resistance to an agent that they cannot internalize. Due to the relatively high molecular weight of its active agent, only BIOGUARD® Barrier Dressings do not pose this risk.