Wound Bioburden and Infection-Related Complications in Diabetic Foot Ulcers
Wound Bioburden and Infection-Related Complications in Diabetic Foot Ulcers
Sue E. Gardner, PhD, RN, CWCN
University of Iowa College of Nursing, Iowa City, Iowa, sue-gardner@uiowa.edu, Center for Research in the Implementation of Innovative Strategies in Practice (CRSP), Iowa City VA Medical Center, Iowa City, Iowa
Rita A. Frantz, PhD, RN, CWCN
University of Iowa College of Nursing, Iowa City, Iowa
The identification and diagnosis of diabetic foot ulcer (DFU) infections remains a complex problem. Because inflammatory responses to microbial invasion may be diminished in persons with diabetes, clinical signs of infection are often absent in persons with DFUs when infection is limited to localized tissue. In the absence of these clinical signs, microbial load is believed to be the best indicator of infection. Some researchers, however, believe microbial load to be insignificant and type of organism growing in the ulcer to be most important. Previous studies on the microbiology of DFUs have not provided enough evidence to determine the microbiological parameters of importance.
Infection-related complications of DFUs include wound deterioration, osteomyelitis, and amputation. Risk factors for amputation include age, peripheral vascular disease, low transcutaneous oxygen, smoking, and poor glycemic control. These risk factors are best measured directly with physiological measures of arterial perfusion, glycemic control, sensory neuropathy, plantar pressures, and activity level and by controlling off-loading. DFU bioburden has not been examined as a risk factor for infection-related complications. To address the relationship between wound bioburden and the development of infection-related complications in DFUs, tightly controlled prospective studies based on clearly defined, valid measures of wound bioburden and wound outcomes are needed. This article reviews the literature and proposes a model of hypothesized relationships between wound bioburden—including microbial load, microbial diversity, and pathogenicity of organisms—and the development of infection-related complications.
Key Words: wound infection • diabetic foot ulcers • amputation • osteomyelitis
