How To Assess The Bacterial Burden Of DFUs
There is some controversy about the Marshall Protocol although there are numerous treatment successes utilizing low pulsed doses of bacteriostatic antibiotics such as minocycline, azithromycin (Zithromax), clindamycin, trimethoprim-sulfamethoxazole (Bactrim DS, AR Scientific) and demeclocycline (Declomycin).32
Specifically, Starner and colleagues found that subinhibitory concentrations of azithromycin significantly decreased biomass and maximal thickness in both forming and established biofilms.33 These concentrations of azithromycin inhibited biofilms in all but the most highly resistant isolates. In contrast, subinhibitory concentrations of gentamicin, which is not a bacteriostatic antibiotic, did not affect biofilm formation. The authors found that biofilms actually became resistant to gentamicin at concentrations far above the minimum inhibitory concentration.
In cases of limb salvage, we suggest patient education and co-management with a knowledgeable infectious disease specialist.
The bacterial bioburden in chronic wounds is very difficult to manage due to their highly resistant state in comparison to their planktonic cousins. There is no set protocol in treating a patient with a chronic wound that has bacterial biofilm production.
It is our experience to treat chronic diabetic wounds that demonstrate delayed healing as if they harbor biofilm infections. Aggressive debridement of the wound followed by application of topical antimicrobials is necessary to prevent biofilm and aid in wound closure. With delayed healing of diabetic foot wounds, it is important to fully re-evaluate the wound and change the treatment protocol. If one has ruled out all causative factors, the clinician may need to address bacterial bioburden to facilitate wound closure.
Dr. Pupp is a member of the Residency Training Committee at Providence Hospital in Southfield, Mich. He is a Fellow of the American College of Foot and Ankle Surgeons, and is board certified in foot and ankle surgery by the American Board of Podiatric Surgery.
Dr. Koivunen is an attending physician at Providence Hospital in Southfield, Mich. He is an Associate of the American College of Foot and Ankle Surgeons.