Optimising Antimicrobial Therapy in Diabetic Foot Infections

Comparative study of culture, next-generation sequencing, and immunoassay for identification of pathogen in diabetic foot ulcer

Treatment of deep musculoskeletal infection (MSKI) begins with accurate identification of the offending pathogen, surgical excision/debridement, and a course of culture-directed antibiotics. Despite this, the incidence of recurrent infection continues to rise. A major contributor to this is inaccurate or negative initial cultures. Accurate identification of the main pathogen is paramount to treatment success. This is especially important in treating diabetic foot infections (DFIs) with limb salvage efforts. This study seeks to utilize standard culture, next-generation sequencing (NGS), and immunoassay for newly synthesized antibodies (NSA) to Staphylococcus aureus and Streptococcus agalactiae for diagnosis. This is a level II prospective observational study approved by our IRB. Thirty patients > 18 years of age who presented with a DFI and underwent surgical debridement or amputation by a single academic orthopedic surgeon from October 2018 to September 2019 were enrolled. Intraoperative samples were obtained from the base of the wound and sent for culture, NGS, and a peripheral blood sample was obtained at the time of diagnosis. NGS and culture were highly correlated for S. aureus (κ = 0.86) and S. agalactiae (κ = 1.0), NSA immunoassay and culture demonstrated a fair correlation for S. aureus (κ = 0.18) and S. agalactiae (κ = 0.67), and NGS and NSA immunoassay demonstrated fair correlation for S. aureus (κ = 0.1667) and S. agalactiae (κ = 0.67). Our study demonstrates a high concordance between culture and NGS in identifying the dominant pathogen in DFU. NGS may be a useful adjunct in DFI diagnosis.

A Comparative Analysis of Antibiotic Usage in Diabetic Foot Infections Against Healing Time

The study aimed to analyze bacterial flora in diabetic foot infection, empiric and targeted antibiotic therapy, and factors influencing wound healing duration. The study we undertook a review analysis of data in 118 cases of diabetic foot among 98 patients who reported to the Wound Care Clinic in Warsaw, Poland between 01/2014 and 12/2018. Collected data included sociodemographic data, wounds information, used treatment, results of the microbiological examination, and empiric and targeted antibiotic therapy. For purposes of identifying the empirical and targeted antibiotic compatibility, the patients were divided into subgroups: ETA+ (compatibility of empiric-targeted antibiotic), ETA- (non-compatibility of empiric-targeted antibiotic), NEA (no empiric antibiotic), and NTA (no targeted antibiotic). The study group consisted of men, N = 71 (72.4%) and women, N = 27 (27.6%). Twenty patients (20.4%) were diagnosed as obese according to the body mass index classification. Staphylococcus aureus and Enterococcus faecalis were identified in most cases [N = 53 (24.4%), and N = 41 (18.9%), respectively]. Sixteen patients (13.6%) received gentamycin locally. Amoxicillin with clavulanic acid, clindamycin, and levofloxacin were the most frequently used antibiotics as empiric therapy; meanwhile, in targeted therapy, amoxicillin with clavulanic acid and levofloxacin were most frequently used. Empiric and targeted antibiotic therapies were compatible in 65 (55.1%) cases. The duration of healing did not differ between selected subgroups, and was longer in obese patients (p = .001). Other variables did not influence the healing time. The use of empiric antibiotic therapy before targeted therapy and the topical use of gentamycin did not reduce the healing time of diabetic foot infection. The healing time of diabetic foot infection was longer in obese patients than in nonobese patients.

Combining local antibiotic delivery with heparinized nanohydroxyapatite/collagen bone substitute: A novel strategy for osteomyelitis treatment

Osteomyelitis is a major challenge in bone surgery and conventional treatment is frequently ineffective to control the infection, with an alternative approach being required. In the present work, a heparinized nanohydroxyapatite/collagen biocomposite was produced in granular form, and loaded with vancomycin, to work as a local drug delivery system for osteomyelitis and as a bone substitute. This strategy involves the local delivery of high concentrations of vancomycin, to eradicate the infection. Additionally, these granules work as a scaffold with regenerative properties, to induce bone regeneration after antibiotic release. The heparinized nanohydroxyapatite/collagen granular bone substitute was produced using two different sintering temperatures to study their effect on granules properties and on vancomycin release profile. Morphological, topographic, chemical and mechanical characterization were carried out for granules sintered at both temperatures and some relevant differences were found. The mechanical strength was increased by several orders of magnitude with increasing sintering temperature, being able to maintain their porous macrostructure and withstand important processes for their commercialization such as packaging, shipping and surgical manipulation. The nanohydroxyapatite/collagen granules were able to release high concentrations of vancomycin, always above MIC, for 19 days. The released antibiotic was able to eradicate both planktonic and sessile methicillin-resistant Staphylococcus aureus. The cytotoxicity was assessed according to ISO 10993-5:2009 and the granules sintered at higher temperature showed no cytotoxic effect. Considering these results nanohydroxyapatite/collagen biocomposite loaded with vancomycin is a promising solution for osteomyelitis treatment.

Structural and functional insights into a novel two-component endolysin encoded by a single gene in Enterococcus faecalis phage

Using bacteriophage-derived endolysins as an alternative strategy for fighting drug-resistant bacteria has recently been garnering renewed interest. However, their application is still hindered by their narrow spectra of activity. In our previous work, we demonstrated that the endolysin LysIME-EF1 possesses efficient bactericidal activity against multiple strains of Enterococcus faecalis (E. faecalis). Herein, we observed an 8 kDa fragment and hypothesized that it contributes to LysIME-EF1 lytic activity. To examine our hypothesis, we determined the structure of LysIME-EF1 at 1.75 Å resolution. LysIME-EF1 exhibits a unique architecture in which one full-length LysIME-EF1 forms a tetramer with three additional C-terminal cell-wall binding domains (CBDs) that correspond to the abovementioned 8 kDa fragment. Furthermore, we identified an internal ribosomal binding site (RBS) and alternative start codon within LysIME-EF1 gene, which are demonstrated to be responsible for the translation of the truncated CBD. To elucidate the molecular mechanism for the lytic activity of LysIME-EF1, we combined mutagenesis, lytic activity assays and in vivo animal infection experiments. The results confirmed that the additional LysIME-EF1 CBDs are important for LysIME-EF1 architecture and its lytic activity. To our knowledge, this is the first determined structure of multimeric endolysin encoded by a single gene in E. faecalis phages. As such, it may provide valuable insights into designing potent endolysins against the opportunistic pathogen E. faecalis.

LysIME-EF1, an endolysin that lyses E. faecalis, displays the prospect of treating E. faecalis infection. We find that the C-terminal cell-wall binding domain (CBD) is important for the lytic activity of LysIME-EF1. By determining the crystal structures of wild type (WT) LysIME-EF1 and its C-terminal CBD, this study reveals how the holoenzyme is organized to carry out its highly efficient lytic activity. Our finding provides structural and functional evidence that LysIME-EF1 belongs to a unique two-component multimeric endolysin encoded by a single gene.

The effect of combined photobiomodulation and curcumin on skin wound healing in type I diabetes in rats

The purpose of the present scientific study was to analyze the effects of combined pulsed wave Photobiomodulation (PW PBM) and Curcumin on the microbial flora; in addition, the tensiometrical wounds properties for type one diabetes mellitus (TIDM) in an experimental animal model. TIDM induction was performed in thirty rats. In the entire animals, one full-thickness excision was implemented on their backs. Randomly, the divisions of rats into 5 groups took place. The primary group was considered as the control group and did not receive any treatment. The secondary group (placebo) received sesame oil by gastric gavage. The third group received PWPBM (890 nm, 80 Hz, 0.2 J/cm²). The fourth group received curcumin (40 mg/kg, which was dissolved in sesame oil) by gastric gavage. Eventually, the fifth group received PW PBM + curcumin. Precisely, on day 7, microbiological examinations, and on the 15th day microbiological and tensiometrical examinations were conducted. The data were analyzed by statistical tests. PW PBM, significantly exacerbated tensiometrical properties of the TIDM repairing wound. PW PBM, curcumin, and PWPBM + curcumin significantly decreased colony forming units compared to the control and the placebo groups indeed. It was remarkably attained that PW PBM significantly accelerated the process of wound healing in the STZ-induced TIDM. The PW PBM was statistically more compelling compared to the curcumin and PWPBM + curcumin. PW PBM, curcumin, and PWPBM + curcumin significantly decreased colony forming units compared to the control and placebo groups.

Efficient induction of antimicrobial activity with vancomycin nanoparticle-loaded poly(trimethylene carbonate) localized drug delivery system

Surgery and the local placement of an antibiotic are the predominant therapies to treat chronic osteomyelitis. Vancomycin-loaded N-trimethyl chitosan nanoparticles (VCM/TMC NPs) as a potential drug delivery system have high intracellular penetration and effective intracellular antibacterial activity. This study investigated the effects of a biocompatible material, poly(trimethylene carbonate) (PTMC), to increase the sustained effectiveness of an intracellular antibiotic and its potential application in antibiotic delivery. VCM/TMC NP-PTMC was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy to determine the morphology, stability and chemical interaction of the drug with the polymer. Further, the biodegradation, antibacterial activity, protein adsorption, cell proliferation and drug release characteristics were evaluated. In addition, a Staphylococcus aureus-induced osteomyelitis rabbit model was used to investigate the antibiotic activity and bone repair capability of VCM/TMC NP-PTMC. The results showed that the composite beads of VCM/TMC NPs followed a sustained and slow release pattern and had excellent antibacterial activity and a higher protein adsorption and cell proliferation rate than the VCM-PTMC in vitro. Furthermore, VCM/TMC NP-PTMC inhibits bacteria and promotes bone repair in vivo. Thus, VCM/TMC NP-PTMC might be beneficial in periodontal management to reduce the bacterial load at the infection site and promote bone repair.

Diabetic foot ulcer--A review on pathophysiology, classification and microbial etiology

As the prevalence of diabetes is increasing globally, secondary complications associated to this endocrinal disorder are also ascending. Diabetic foot ulcers are potentially modifying complications. Disruption of harmony in glucose homeostasis causes hyperglycemic status, results in activation of certain metabolic pathways which in their abnormal state subsequently leads to development of vascular insufficiency, nerve damages headed by ulceration in lower extremity due to plantar pressures and foot deformity. Insult to foot caused by trauma at the affected site goes unnoticeable to patient due to loss of sensation. Among the above mention causes, resistance to infection is also considered as chief modulator of pathophysiological image of diabetic foot lesions. Healing as well as non-healing nature of ulcer relies upon the wound microbial communities and the extent of their pathogenicity. A validated classification system of foot ulcer is primarily necessary for clinicians in management of diabetic foot problems. Another aspect which needs management is proper identification of causative pathogen causing infection. The way of approaches presently employed in the diagnosis for treatment of foot ulcer colonized by different microbes is conventional techniques. Conventional diagnostic methods are widely acceptable since decades. But in recent years newly invented molecular techniques are exploring the use of 16S ribosomal regions specific to prokaryotes in bacterial identification and quantification. Molecular techniques would be a better choice if engaged, in finding the specific species harboring the wound.

Antibiotherapy with and without bone debridement in diabetic foot osteomyelitis: A retrospective cohort study

BACKGROUND AND OBJECTIVE

The treatment of diabetic foot osteomyelitis (DFO) is a controversial issue, with disagreement regarding whether the best treatment is surgical or conservative. The purpose of this study was to compare the outcome of patients with DFO who were treated with antibiotherapy alone and those who underwent concurrent minor amputation.

METHODS

Hospital records of patients who were diagnosed as having DFO within a 2-year study period were retrospectively reviewed. Patients were divided into two groups: those who received antibiotherapy alone and those who underwent concurrent minor amputation. Groups were compared in terms of duration in hospitalization, antibiotherapy, and wound healing.

RESULTS

Thirty seven patients were included in the study. These comprised patients who received antibiotherapy alone (ABG, n=15) and patients who underwent concurrent minor amputation (AB-MAG, n=22). Hospitalization duration was 37.2 (± 16.2) days in ABG and 52.8 (± 40.2) days in AB-MAG (p = 0.166). Mean duration of antibiotherapy was 45.0 (± 21.7) days in ABG and 47.7 (± 19) days in AB-MAG (p = 0.689). Wound healing duration was 265.2 (± 132.7) days in ABG and 222.6 (± 85.9) days in AB-MAG (p = 0.243). None of the outcome measures were significantly different between ABG and AB-MAG.

CONCLUSIONS

Our results have shown similar outcomes for both patient groups who received antibiotherapy alone and who underwent concurrent minor amputations. Considering the small sample sizes in this study, it is important to confirm these results on a larger scale.

Characterization of Enterococcus faecalis phage IME-EF1 and its endolysin

Enterococcus faecalis is increasingly becoming an important nosocomial infection opportunistic pathogen. E. faecalis can easily obtain drug resistance, making it difficult to be controlled in clinical settings. Using bacteriophage as an alternative treatment to drug-resistant bacteria has been revitalized recently, especially for fighting drug-resistant bacteria. In this research, an E. faecalis bacteriophage named IME-EF1 was isolated from hospital sewage. Whole genomic sequence analysis demonstrated that the isolated IME-EF1 belong to the Siphoviridae family, and has a linear double-stranded DNA genome consisting of 57,081 nucleotides. The IME-EF1 genome has a 40.04% G+C content and contains 98 putative coding sequences. In addition, IME-EF1 has an isometric head with a width of 35 nm to 60 nm and length of 75 nm to 90 nm, as well as morphology resembling a tadpole. IME-EF1 can adsorb to its host cells within 9 min, with an absorbance rate more than 99% and a latent period time of 25 min. The endolysin of IME-EF1 contains a CHAP domain in its N-terminal and has a wider bactericidal spectrum than its parental bacteriophage, including 2 strains of vancomycin-resistant E. faecalis. When administrated intraperitoneally, one dose of IME-EF1 or its endolysin can reduce bacterial count in the blood and protected the mice from a lethal challenge of E. faecalis, with a survival rate of 60% or 80%, respectively. Although bacteriophage could rescue mice from bacterial challenge, to the best of our knowledge, this study further supports the potential function of bacteriophage in dealing with E. faecalis infection in vivo. The results also indicated that the newly isolated bacteriophage IME-EF1 enriched the arsenal library of lytic E. faecalis bacteriophages and presented another choice for phage therapy in the future.

In vivo efficacy of humanized ceftaroline fosamil-avibactam exposures in a polymicrobial infection model

Although Gram-positive cocci are the most common pathogens in diabetic foot infections, these infections often are polymicrobial. The objective of this study was to assess the efficacy of a simulated human dose of 600 mg ceftaroline fosamil-600 mg avibactam every 8 h as a 1-h infusion in a polymicrobial in vivo murine model. Seven isolates were used (3 methicillin-resistant Staphylococcus aureus [MRSA] isolates, 1 methicillin-susceptible S. aureus [MSSA] isolate, 1 Escherichia coli isolate, 1 Enterobacter cloacae isolate, and 1 Bacteroides fragilis isolate) in various combinations in an immunocompromised polymicrobial tissue infection to assess the efficacy of the simulated regimen. Each infection was comprised of at least one S. aureus isolate with a MIC of 0.25 to 1 μg/ml and one Enterobacteriaceae isolate with a MIC of 1 or 4 μg/ml. Eight of 16 infections also included B. fragilis, with a MIC of 0.5 μg/ml, as a third organism. Efficacy was evaluated after 24 h as the change in log10 CFU from the level of 0-h controls. Efficacy was seen against all isolate combinations, with at least a 1-log kill against Enterobacteriaceae and a minimum of a 2-log kill against S. aureus and B. fragilis isolates. These bacterial reductions correlate with free drug concentration above the MIC (fT>MIC) produced by the humanized regimen of 100, 86, and 56% at MICs of 1, 2, and 4 μg/ml, respectively. The humanized regimen of 600 mg ceftaroline fosamil-600 mg avibactam every 8 h as a 1-h infusion showed predictable efficacy against all infections tested in this model. These data support further clinical investigation of ceftaroline fosamil-avibactam for the treatment of polymicrobial tissue infections.

Systematic approach to treat chronic osteomyelitis through localized drug delivery system: bench to bed side

Chronic osteomyelitis is a challenging setback to the orthopedic surgeons in deciding an optimal therapeutic strategy. Conversely, patients feel frustrated of the therapeutic outcomes and development of adverse drug effects, if any. Present investigation deals with extensive approach incorporating in vivo animal experimentation and human application to treat chronic osteomyelitis, using antibiotic loaded porous hydroxyapatite scaffolds. Micro- to macro-porous hydroxyapatite scaffolds impregnated with antibiotic ceftriaxone-sulbactam sodium (CFS) were fabricated and subsequently evaluated by in vivo animal model after developing osteomyelitis in rabbit tibia. Finally 10 nos. of human osteomyelitis patients involving long bone and mandible were studied for histopathology, radiology, pus culture, 3D CT etc. up to 8-18 months post-operatively. It was established up to animal trial stage that 50N50H samples [with 50-55% porosity, average pore size 110 μm, higher interconnectivity (10-100 μm), and moderately high drug adsorption efficiency (50%)] showed efficient drug release up to 42 days than parenteral group based on infection eradication and new bone formation. In vivo human bone showed gradual evidence of new bone formation and fracture union with organized callus without recurrence of infection even after 8 months. This may be a new, alternative, cost effective and ideal therapeutic strategy for chronic osteomyelitis treatment in human patients.

Biofilm inhibitory and eradicating activity of wound care products against Staphylococcus aureus and Staphylococcus epidermidis biofilms in an in vitro chronic wound model

AIMS

Although several factors contribute to wound healing, bacterial infections and the presence of biofilm can significantly affect healing. Despite that this clearly indicates that therapies should address biofilm in wounds, only few wound care products have been evaluated for their antibiofilm effect. For this reason, we developed a rapid quantification approach to investigate the efficacy of wound care products on wounds infected with Staphylococcus spp.

METHODS AND RESULTS

An in vitro chronic wound infection model was used in which a fluorescent Staph. aureus strain was used to allow the rapid quantification of the bacterial burden after treatment. A good correlation was observed between the fluorescence signal and the bacterial counts. When evaluated in this model, several commonly used wound dressings and wound care products inhibited biofilm formation resulting in a decrease between one and seven log CFU per biofilm compared with biofilm formed in the absence of products. In contrast, most dressings only moderately affected mature biofilms.

CONCLUSION

Our model allowed the rapid quantification of the bacterial burden after treatment. However, the efficacy of treatment varied between the different types of dressings and/or wound care products.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our model can be used to compare the efficacy of wound care products to inhibit biofilm formation and/or eradicate mature biofilms. In addition, the results indicate that treatment of infected wounds should be started as soon as possible and that novel products with more potent antibiofilm activity are needed.

Diabetic foot infections with osteomyelitis: efficacy of combined surgical and medical treatment

Diabetic foot infections are a high risk for lower extremity amputation in patients with dense peripheral neuropathy and/or peripheral vascular disease. When they present with concomitant osteomyelitis, it poses a great challenge to the surgical and medical teams with continuing debates regarding the treatment strategy. A cohort prospective study conducted between October 2005 and October 2010 included 330 diabetic patients with osteomyelitis mainly involving the forefoot (study group) and 1,808 patients without foot osteomyelitis (control group). Diagnosis of osteomyelitis was based on probing to bone test with bone cultures for microbiological studies and/or repeated plain radiographic findings. Surgical treatment included debridement, sequestrectomy, resections of metatarsal and digital bones, or toe amputation. Antibiotics were started as empirical and modified according to the final culture and sensitivities for all patients. Patients were followed for at least 1 year after wound healing. The mean age of the study group was 56.7 years (SD = 11.4) compared to the control group of 56.3 years (SD = 12.1), while the male to female ratio was 3:1. At initial presentation, 82.1% (n=271) of the study group had an ulcer penetrating the bone or joint level. The most common pathogens were Staphylococcus aureus (33.3%), Pseudomonas aeruginosa (32.2%), and Escherichia coli (22.2%) with an almost similar pattern in the control group. In the study group, wound healing occurred in less than 6 months in 73% of patients compared to 89.9% in the control group. In the study group, 52 patients (15.8%) had a major lower extremity amputation versus 61 in the control group (3.4%) (P=0.001). During the postoperative follow-up visits, 12.1% of patients in each group developed wound recurrence. In conclusion, combined surgical and medical treatment for diabetic foot osteomyelitis can achieve acceptable limb salvage rate and also reduce the duration of time to healing along with the duration of antibiotic treatment and wound recurrence rate.

2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections

Foot infections are a common and serious problem in persons with diabetes. Diabetic foot infections (DFIs) typically begin in a wound, most often a neuropathic ulceration. While all wounds are colonized with microorganisms, the presence of infection is defined by ≥2 classic findings of inflammation or purulence. Infections are then classified into mild (superficial and limited in size and depth), moderate (deeper or more extensive), or severe (accompanied by systemic signs or metabolic perturbations). This classification system, along with a vascular assessment, helps determine which patients should be hospitalized, which may require special imaging procedures or surgical interventions, and which will require amputation. Most DFIs are polymicrobial, with aerobic gram-positive cocci (GPC), and especially staphylococci, the most common causative organisms. Aerobic gram-negative bacilli are frequently copathogens in infections that are chronic or follow antibiotic treatment, and obligate anaerobes may be copathogens in ischemic or necrotic wounds. Wounds without evidence of soft tissue or bone infection do not require antibiotic therapy. For infected wounds, obtain a post-debridement specimen (preferably of tissue) for aerobic and anaerobic culture. Empiric antibiotic therapy can be narrowly targeted at GPC in many acutely infected patients, but those at risk for infection with antibiotic-resistant organisms or with chronic, previously treated, or severe infections usually require broader spectrum regimens. Imaging is helpful in most DFIs; plain radiographs may be sufficient, but magnetic resonance imaging is far more sensitive and specific. Osteomyelitis occurs in many diabetic patients with a foot wound and can be difficult to diagnose (optimally defined by bone culture and histology) and treat (often requiring surgical debridement or resection, and/or prolonged antibiotic therapy). Most DFIs require some surgical intervention, ranging from minor (debridement) to major (resection, amputation). Wounds must also be properly dressed and off-loaded of pressure, and patients need regular follow-up. An ischemic foot may require revascularization, and some nonresponding patients may benefit from selected adjunctive measures. Employing multidisciplinary foot teams improves outcomes. Clinicians and healthcare organizations should attempt to monitor, and thereby improve, their outcomes and processes in caring for DFIs.

Treatment algorithms for chronic osteomyelitis

BACKGROUND

Osteomyelitis was described many years ago but is still incompletely understood. Its exogenously acquired form is likely to become more common as the population ages. We discuss biofilm formation as a clinically relevant pathophysiological model and present current recommendations for the treatment of osteomyelitis.

METHODS

We selectively searched the PubMed and Cochrane databases for articles on the treatment of chronic osteomyelitis with local and systemic antibiotics and with surgery. The biofilm hypothesis is discussed in the light of the current literature.

RESULTS

There is still no consensus on either the definition of osteomyelitis or the criteria for its diagnosis. Most of the published studies cannot be compared with one another, and there is a lack of scientific evidence to guide treatment. The therapeutic recommendations are, therefore, based on the findings of individual studies and on current textbooks. There are two approaches to treatment, with either curative or palliative intent; surgery is now the most important treatment modality in both. In addition to surgery, antibiotics must also be given, with the choice of agent determined by the sensitivity spectrum of the pathogen.

CONCLUSION

Surgery combined with anti-infective chemotherapy leads to long-lasting containment of infection in 70% to 90% of cases. Suitable drugs are not yet available for the eradication of biofilm-producing bacteria.

Antibiotic impregnated cement spacer for salvage of diabetic osteomyelitis

BACKGROUND

Florid infection and osteomyelitis of the forefoot in patients with diabetic neuropathy often requires minor amputation, with risk of subsequent reulceration, reamputation, and patient dissatisfaction. We investigated use of an antibiotic-impregnated cement spacer (ACS) to release antibiotic locally to resolve residual infection and to fill the cavity created by debridement.

METHODS

We report 23 cases of osteomyelitis and associated severe infection of forefoot joints in 20 consecutive patients, age 60.3 +/- 13.4 years. Antibiotic-impregnated cement, extensive meticulous debridement, and ACS placement to fill the gap were employed in all cases. Deep cultures were taken routinely. Fixation with Kirschner wires was used as necessary. Mean followup was 21.2 +/- 10.2 months. A successful result was resolution of infection and wound healing to full skin closure without amputation.

RESULTS

Of 23 cases, 21 (91.3%) healed and two required toe amputation. ACS was left permanently in 10 patients, removed with arthrodesis in six, and removed without arthrodesis in five. One patient recovered but subsequently underwent transtibial amputation due to infection of a different site.

CONCLUSION

Severe infection associated with osteomyelitis of the foot in diabetic patients was successfully treated with extensive debridement and use of ACS, which filled the void created by debridement. Amputation was avoided in most patients. This procedure allowed extensive debridement through filling large voids with ACS, with prolonged antibiotic release.

Clinical application of treating biofilms-associated infections in family medicine

The management of common infections in family medicine may be complicated by poor treatment response or infection recurrence. In many cases, difficulty in treating these infections can be explained by the important role of biofilms, complex microbial communities with unique survival properties that promote infection resistance, recurrence, and persistence. Biofilms have been demonstrated to play important roles in infections involving the sinuses, ears, and ischemic wounds. Biofilms also commonly grow on medical devices, such as indwelling catheters, where they serve as an important nidus of persistent infection. Understanding the role of biofilms in medical infections suggests preventive and treatment strategies that will directly target the important resistive mechanisms of biofilms.

Medical therapy of diabetic foot infections

Diabetic foot infections are a common and often serious problem, accounting for more hospital bed days than any other complication of diabetes. Despite advances in antibiotic drug therapy and surgical management, these infections continue to be a major risk factor for amputations of the lower extremity. Although a variety of wound size and depth classification systems have been adapted for use in codifying diabetic foot ulcerations, none are specific to infection. In 2003, the International Working Group on the Diabetic Foot developed guidelines for managing diabetic foot infections, including the first severity scale specific to these infections. The following year, the Infectious Diseases Society of America published their diabetic foot infection guidelines. Herein, we review some of the critical points from the Executive Summary of the Infectious Diseases Society of America document and provide a commentary following each issue to update the reader on any pertinent changes that have occurred since publication of the original document in 2004. The importance of a multidisciplinary limb salvage team, apropos of this special issue jointly published by the American Podiatric Medical Association and the Society for Vascular Surgery, cannot be overstated.

Salvaging diabetic foot through debridement, pressure alleviation, metabolic control, and antibiotics

There is a fatalist perception of diabetic foot because the argument of "small-vessel disease" prevails. This is the report of a cohort study of patients facing a formal recommendation for major foot amputation to assess how many can be saved with a conventional treatment, defined as debridement, pressure alleviation, metabolic control, and antibiotics. The primary efficacy measurement was the salvage of the limb at the follow-up visit between 25 and 35 days after the first consultation. The secondary efficacy measurement was the subsequent epithelization of the ulcerative lesions, following patients for up to 270 days. The cohort consisted of 105 type 2 diabetic patients; 87 (83%) had severe lesions. A total of 71 patients (68%) required hospitalization. By the intention-to-treat analysis, 89 patients (85%) avoided major amputation. A total of 88 patients were evaluated for complete epithelization, reaching median success by day 120. Overall, 51 patients (49%) underwent minor amputations. It was concluded that there is a high rate of unnecessary major foot amputations, because a diabetic foot can be salvaged across the continuum of severity when patients receive care in a multidisciplinary wound clinic.

Medical therapy of diabetic foot infections

Diabetic foot infections are a common and often serious problem, accounting for a greater number of hospital bed days than any other complication of diabetes. Despite advances in both antibiotic therapy and surgical management, these infections continue to be a major risk factor for amputations of the lower extremity. Although a number of wound size and depth classification systems have been adapted for use in codifying diabetic foot ulcerations, none are specific for infection. In 2003, the International Working Group on the Diabetic Foot developed guidelines for managing diabetic foot infections, including the first severity scale specific for these infections. The following year, the Infectious Diseases Society of America (IDSA) published their Diabetic Foot Infection Guidelines. In this article, we review some of the critical points from the Executive Summary of the IDSA document and provide a commentary following each issue to update the reader on any pertinent changes that have occurred since the publication of the original document in 2004. The importance of a multidisciplinary limb salvage team, apropos this special joint issue of the American Podiatric Medical Association and the Society for Vascular Surgery, cannot be overstated.

Antibiotic optimization in the difficult-to-treat patient with complicated intra-abdominal or complicated skin and skin structure infections: focus on tigecycline

Complicated intra-abdominal and skin and skin structure infections are widely varied in presentation. These infections very often lead to an increase in length of hospital stay, with a resulting increase in costs and mortality. In addition, these infections may be caused by a wide variety of bacteria and are often polymicrobial with the possibility of the presence of antimicrobial-resistant strains, such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, extended-spectrum β-lactamase strains (Escherichia coli, Klebsiella pneumoniae), and K. pneumoniae carbapenemase-producing strains. In combination with patients’ immunosuppression or comorbidities, the treatment and management options for initial therapy success are few. Tigecycline, a new glycylcyline antimicrobial from the tetracycline drug class, represents a viable option for the successful treatment of these infections. It has been shown to have activity against a wide variety of bacteria, including the antimicrobial-resistant strains. As with all tetracycline drugs, it is not recommended for pregnant or nursing women. The potential side effects are those typical of tetracycline drugs: nausea, vomiting, and headaches. Drug–drug interactions are not expected, and renal function monitoring is not necessary.

Novel antibiotics for the management of diabetic foot infections

Foot infections are a major cause of morbidity in diabetic patients. Staphylococcus aureus is the most important pathogen in mild infections; moderate to severe infections are frequently polymicrobial. Multidrug resistance is an increasing problem in isolates from diabetic feet. Worldwide, up to 30% of patients with diabetic foot infection (DFI) are colonised with methicillin-resistant S. aureus (MRSA), whilst extended-spectrum beta-lactamase-producing Gram-negative bacteria are also common in some countries. This emergence of drug resistance has coincided with the launch or imminent availability of many new antibiotics. Most of these were developed to target multidrug-resistant Gram-positive bacteria, although some have a spectrum of activity that includes Gram-negative bacteria and anaerobes. There is a variable amount of experience with these agents in treating skin and skin-structure infections (SSSIs), especially for DFI. However, at least some have a spectrum of activity and/or pharmacological properties that suggest that they may be of value in managing DFIs. The aim of this paper is to review evidence for the efficacy of new antibiotics in the management of SSSIs, including any data relating specifically to the diabetic foot, and to consider where they might fit into the therapeutic armory against DFI.

Osteomyelitis and the role of biofilms in chronic infection

Understanding the mechanisms implicated in the initial attachment, development, and maturation of a biofilm phenotype are of tremendous importance for their effect on the medical, industrial, and public health arenas. This review explores the current understanding of the nature of biofilms and the impact that molecular interactions between the bacteria themselves, as well as between bacteria and the host, may have on biofilm development and phenotype using the nonmotile Gram-positive coccus, Staphylococcus aureus, as an example.

Infections in Diabetes Mellitus and Hyperglycemia

Infections in diabetes mellitus are relatively more common and serious. Diabetic patients run the risk of acute metabolic decompensation during infections, and conversely patients with metabolic decompensation are at higher risk of certain invasive infections. Tight glycemic control is of paramount importance during acute infected or high stress state. Infections in diabetic patients result in extended hospital stays and additional financial burden. Given the risks of not alleviating the metabolic dysregulation and the benefits of decent glycemic control, it is necessary that besides antimicrobial therapy, equal emphasis be placed on intensified glycemic control.