Efficacy of Polyhexamethylene Biguanide-containing Antimicrobial Foam Dressing Against MRSA Relative to Standard Foam Dressing

Many modern foam wound dressings possess a variety of attributes that are designed to create a supportive wound-healing environment. These attributes include absorbing exudate, providing optimum moisture balance at the wound surface, and preventing maceration of surrounding tissue. However, studies suggest that controlling wound bioburden should also be targeted when developing wound therapeutics. Thus, traditional foam dressings may absorb a copious amount of fluid, but may also provide an environment where microbes can grow unchallenged, leading to an increase in wound bioburden. However, antimicrobial foam dressings may prevent or reduce microbial growth, increasing the potential for wound healing. Studies reported herein evaluated the efficacy of 0.5% polyhexamethylene biguanide (PHMB) treated dressings to prevent the growth of methicillin-resistant Staphylococcus aureus (MRSA). An antimicrobial foam (Kendall (TM) AMD, Covidien, Mansfield, MA), which contains PHMB and a standard foam dressing (Copa (TM), Covidien, Mansfield, MA), which contains no PHMB (control), were directly inoculated with clinical isolate of MRSA and placed on a growth medium for selected time intervals. The presence or absence of microbial growth was quantified using plate counts and. was visually assessed using scanning electron microscopy. At all time points, the antimicrobial foam dressing significantly reduced the MRSA growth compared to the control dressing. Similar results were also obtained in the microscopic evaluations.