Treatment Options For Diabetic Foot Infections
- Volume 16 - Issue 1 - January 2003
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Surveying The Antibiotic Possibilities
Antibiotic-impregnated calcium sulphate pellets have been used for the local treatment of deep, infected, diabetic foot wounds with or without osteomyelitis. The qualities of biocompatibility and biodegradability along with a slow release of high levels of a locally concentrated antibiotic make the pellets a beneficial therapy.
This product is now commercially available in a kit that consists of the powdered calcium sulfate and a curing solution. The one time use kit is prepared under sterile conditions in the operating room and a powdered antibiotic (i.e. 500 mg of vancomycin prior to hardening) is added. The mixture is then placed into a formation template to fabricate pellets of various sizes from 3 to 6 mm. The curing takes less than two minutes. You would place the radiopaque pellets in the open wound prior to closure. The pellets are resorbed completely over approximately six weeks and deliver a steady state antibiotic concentration directly to the wound site. Controlled studies are necessary to determine the efficacy of this modality in treating diabetic foot infections, but early clinical results have been impressive.
Empiric antibiotic therapy should include broad spectrum antibiotics capable of covering the most common pathogens found in diabetic infections. Empiric treatment of moderate to severe infections should include agents active against Staph, Strep, gram-negatives, bacilli and anaerobes. Single agents include carbapenems or beta-lactam/beta-lactamase inhibitor combinations such as piperacillin/tazobactam (Zosyn), ticarcillin/clavulanate (Timentin) or ampicillin/sulbactam (Unasyn), imipenem/cilastin (Primaxin), vancomycin, anminoglycosides and ertrapenem (Invanz) given IV. Combination therapy often includes clindamycin in addition to the previously mentioned antibiotics.
In a study to be published in the near future, linezolid (oral) was proven to be at least comparable to aminopenicillins (IV) in a randomized international multicenter trial.7 (See “New Study Reveals Promise Of Linezolid For Diabetic Infections,” News And Trends, December 2002 issue.)
Overwhelming evidence suggests that by striving to ensure optimal glucose control, proper wound care and appropriate surgical and antibiotic therapy, one can control diabetic foot infection and preserve a functional foot in most patients. The current challenge is to not only continue to develop new treatments but to master existing ones in a cost-effective, evidence-based and multidisciplinary manner. Not only should we collaborate with various medical specialists, we must also recognize that the patient is the most important member of the team in order to win the battle of saving limbs.
Dr. Jones is a first year resident at the University of Texas Health Science Center in San Antonio, Texas.
Dr. Steinberg is an Assistant Professor in the Department of Orthopaedics/Podiatry Service at the University of Texas Health Science Center.
1. Lipsky BA. Osteomyelitis of the foot in diabetic patients. Clin Infect Dis 1997; 25: 1318-1326.
2. Caputo GM, Cavanagh PR, Ulbrecht JS, et al. Assessment and management of foot disease in patients with diabetes. N Engl J Med 1994; 331: 854-860.
3. Brodsky JW, Schneidler C. Diabetic Foot Infections. Ortho Clin of North America. 1991; 22:3 473-489.
4. Armstrong DG, Mossel J, Short B, Nixon BP, Knowles EA, et al. Maggot debridement therapy: a primer. JAPMA. 2002; 92:7 398-401.
5. Gough A, Clapperton M, Rolando N, et al. Randomized placebo-controlled trial of granulocyte-colony stimulating factor in diabetic foot infections. Lancet. 1997; 350: 855-859.
6. De Lalla F, Pelizzer G, Strazzabosco M, et al. A randomized prospective controlled trial of granulocyte-colony stimulating factor (G-CSF) in limb-threatening diabetic foot infections.
7. Lipsky BA. Abstract: Treating Diabetic Foot Infections with Linezolid vs. Aminopenicillins: A Randomized International Multicenter Trial.
8. Levin and O’Neal’s The Diabetic Foot. Edited by Bowker JH, Pfeifer MA. Sixth ed. 2001.