Biofilms in Diabetic Foot Ulcers: Significance and Clinical Relevance

Abstract

Foot infections are the main disabling complication in patients with diabetes mellitus. These infections can lead to lower-limb amputation, increasing mortality and decreasing the quality of life. Biofilm formation is an important pathophysiology step in diabetic foot ulcers (DFU)—it plays a main role in the disease progression and chronicity of the lesion, the development of antibiotic resistance, and makes wound healing difficult to treat. The main problem is the difficulty in distinguishing between infection and colonization in DFU. The bacteria present in DFU are organized into functionally equivalent pathogroups that allow for close interactions between the bacteria within the biofilm. Consequently, some bacterial species that alone would be considered non-pathogenic, or incapable of maintaining a chronic infection, could co-aggregate symbiotically in a pathogenic biofilm and act synergistically to cause a chronic infection. In this review, we discuss current knowledge on biofilm formation, its presence in DFU, how the diabetic environment affects biofilm formation and its regulation, and the clinical implications.

Adaptation of Staphylococcus aureus in a Medium Mimicking a Diabetic Foot Environment

“…Various studies have described the DFU microbiota to determine the role of microorganisms [ 33 ]. Although they have produced interesting results and confirmed that the microbiota is a highly dynamic microbial community that maintains a relationship with the host, better understanding of the complex competitive or synergistic interaction between commensal and/or pathogenic microorganisms is necessary as it could affect the severity and progression of the wound [ 7 ]. The virulence capacity of a bacterium has a direct impact on the equilibrium between colonization and infection [ 34 ].…”

“…Here, we evaluated the role of a high glucose concentration and sub-MICs of two antibiotics in a WLM mimicking the conditions encountered in DFU on a series of clinical bacterial strains isolated from this clinical situation. To study bacterial virulence, most studies have previously used in vitro planktonic cultures on rich media or in vivo diabetes animal models (e.g., db/db mice), but without the ability to create genuine wound chronicity [ 7 ]. The WLM represents a convenient and reliable model to study bacteria in a relevant environment [ 29 , 30 ].…”

“…Outcomes in patients presenting with a DFI are poor with a high mortality following this complication (around 15% in the following year) [ 1 , 5 ]. DFIs are polymicrobial and Staphylococcus aureus is the most frequent pathogen isolated [ 6 , 7 ]. This Gram-positive coccus is a leading cause of a wide range of diseases, from skin and soft tissue infections (SSTIs) (e.g., impetigo, carbuncles) to life-threatening bacteremia, toxic shock syndrome, endocarditis, and osteomyelitis [ 6 , 8 ].…”

Dermal Drivers of Injury-Induced Inflammation: Contribution of Adipocytes and Fibroblasts

“…Biofilms also contribute to significant tissue destruction and sustained inflammation in diabetic wounds [ 203 ]. In addition to its potential role in early inflammation, reduced cathelicidin LL37 in diabetic wounds [ 194 ] may also contribute to biofilm control [ 204 ].…”

Review Article: The Role of Bacterial Biofilms in Chronic Diseases

“…The formation of different bacterial biofilms is shown in figure 6 (33) . Figure 6: the steps of the formation of bacterial biofilm (33) Neut and his coworker did a research in 2011 (34) , they reached evidences that shows the biofilms in DFU using a certain techniques and microscopes, this finding was confirmed by Malik and his coworkers in 2013 (35) who study more than 170 DFU cases, and they found around 70% of the cases under studies suffers from DFI (Diabetic Food Infection).…”