Diabetic Foot Ulcer Microbiome: One Small Step for Molecular Microbiology . . . One Giant Leap for Understanding Diabetic Foot Ulcers?
- 1Department of Medicine, University of Washington, Seattle, Washington
- 2Department of Medical Specialties, University of Geneva, Geneva, Switzerland
- 3Medical Sciences Division, University of Oxford, Oxford, U.K.
- 4Department of Diabetology and Nutritional Diseases, Medical Centre, University Hospital of Nîmes, Nîmes, France
- 5Department of Bacteriology, Carémeau University Hospital, Nîmes, France
- 6National Institute of Health and Medical Research, U1047, Montpellier 1 University, Faculty of Medicine, Nîmes, France
- Corresponding author: Benjamin A. Lipsky, .
Foot infections in individuals with diabetes are a major cause of morbidity, constituting the most common reason for both diabetes-related hospitalization and lower extremity amputations (1,2). Optimal treatment of these diabetic foot infections requires recognizing which foot ulcers are infected and prescribing pathogen-appropriate antibiotic therapy. Most experts concur that diagnosing infection should be based on the presence of primary or secondary clinical signs and symptoms of inflammation (1,2), but the frequent presence of peripheral neuropathy or peripheral arterial disease may confound the diagnosis (3). Thus, some favor using bacterial density in wound cultures to help diagnose infection (4,5). This concept is based on the belief that a high wound “bioburden” leads to “critical colonization,” an intermediary state on the way to overt infection that may be responsible for delayed wound healing and that may respond to antimicrobial therapy (6,7). Certainly, treatment of clinically overt diabetic foot infection requires appropriate systemic antibiotic therapy, which is best guided by identifying the causative pathogens.
Indigenous microorganisms residing on humans were first observed more than 300 years ago (8), and for over 150 years clinicians have relied on the results of cultures to define the causative organisms in bacterial infections. Unfortunately, culture-based techniques select for species that flourish under the typical nutritional and physiological conditions of the diagnostic microbiology laboratory, not necessarily the most abundant or clinically important organisms (9). In the past decade, studies with molecular microbiological techniques have raised doubts about …