Bacteriological study of diabetic foot infections

AIMS: The polymicrobial nature of diabetic foot infection has been well documented in the literature. Patients with diabetic foot infection not exposed to antibiotics are not well studied before. The relative frequency of bacterial isolates cultured from community-acquired foot infections that are not exposed to antimicrobial agents for 30 days is studied. In addition, the bacterial comparative in vitro susceptibility to the commonly used antibacterial agents is assessed. METHODS: This is a prospective study in which the infected wounds of 86 consecutive diabetic patients seen in the diabetic foot clinic in Adan Teaching Hospital were cultured when visiting the clinic. The patients did not receive antimicrobial therapy 30 days prior to taking the cultures. The specimen was cultured using aerobic and anaerobic microbiological techniques. Isolates were tested for susceptibility to commonly used antimicrobial therapy. RESULT: Staphylococcus aureus was the most common isolate, being recovered from 38.4% of cases. Other organisms were Pseudomonas aeruginosa (17.5%) and Proteus mirabilis (18%), anaerobic gram-negative organisms (10.5%), mainly Bacteroides fragilis. Imipenem, meropenem, and cefepime were the most effective agents against gram-negative organisms. Vancomycin was the most effective against gram-positive organisms. CONCLUSION: S. aureus and P. aeruginosa were the most common causes of diabetic foot infections. Anaerobic organisms are still a common cause for infection, although the prevalence is less. These wounds may require use of combined antimicrobial therapy for initial management.     

Diagnosing and treating diabetic foot infections

Foot infections are a common, complex and costly complication of diabetes. We have made considerable progress in establishing consensus definitions for defining infection. Similarly, we have learned much about the appropriate ways to diagnose both soft tissue and bone infections. Accompanying these advances have been improvements in our knowledge of the proper approaches to antibiotic (and surgical) therapy for diabetic foot infections. Furthermore, investigators have explored the value of various adjunctive therapies, especially granulocyte colony stimulating factors and hyperbaric oxygen, for improving outcomes. This paper presents a summary of a minisymposium on infection of the diabetic foot that was held at the fourth International Symposium on the Diabetic Foot, in Noordwijkerhout, The Netherlands.     

Prevalence of yeast in diabetic foot infections

Diabetic foot infections are a serious threat which cause a long term of hospitalization of diabetes patients and lead to amputations. Hence, prompt diagnosis is an important criterion in the treatment of these infections. This study was carried out to determine the prevalence of yeast in diabetic foot infections. The pus samples were collected from patients presenting with diabetic foot ulcer and processed for microbiological investigation. The patients investigated comprised of 82 males and 78 females. Most of the patients were grade I ulcers followed by grade II ulcers. Out of 160 samples, 138 samples were culture positive, in which yeast isolate Candida glabrata was the predominant isolate followed by Candida albicans, Candida dubliniensis, Candida krusei and Candida tropicalis. C. albicans and C. dubliniensis were differentiated by using tobacco agar due to the presence of hyphal fringes. The methylene blue sabouraud dextrose agar and corn meal agar were also used to differentiate C. albicans from non albicans. The antifungal susceptibility pattern showed 29 % of C. albicans was sensitive to Amphotericin B and Clotrimazole, while 75 % of C. glabrata was sensitive to Amphotericin B, Ketoconazole and Itraconazole. C. dublinensis and C. albicans showed the highest percentage of resistant to Ketoconazole, Fluconazole, Nystatin and Itraconazole. Thus, the results indicating that effective alternate drug of choice are required and the proper selection of antifungal agents will play an important role for the treatment of fungal foot infections. This study will also add substantial knowledge of yeast as one of the pathogenic organisms in diabetic foot infections.     

New concepts in managing diabetic foot infections

Recent enhanced attention to diabetic foot infection--in both clinical care and research--has yielded a modified picture of this disorder. It suggests that certain diabetic patients may have important risk factors for the development of infection, and further, infections in these patients may not have the same clinical characteristics as the soft tissue or bony infections found in nondiabetic subjects. Treatment of diabetic patients should therefore be modified to conform to the particular characteristics of their infections.     

Frequency of MRSA in diabetic foot infections

Staphylococcus aureus is one of the most common bacterial pathogens isolated from diabetic foot infections (DFIs). The increasing prevalence of meticillin-resistant S. aureus (MRSA) in patients with diabetes is associated with complications. The aim of this study was to determine the prevalence of S. aureus in DFIs and antibiotic susceptibility patterns of MRSA and non-MRSA isolates. Identification of S. aureus and MRSA was performed by the phenotypic and molecular methods. The Kirby-Bauer and agar dilution methods were performed for determination of antibiotic susceptibility patterns. Thirty-four isolates of S. aureus were isolated from March 2014 to February 2015. The rate of MRSA was 38.23 % according to the disk cefoxitin and oxacillin agar dilution methods, and as by PCR method 12) 35.29 %), isolates were found to have the mecA gene. All MRSA and non-MRSA isolates were susceptible to linezolid and vancomycin. The resistance rate to ceftriaxone was high followed by amoxicillin-clavulanic acid, tetracycline, gentamicin, and erythromycin. The most common bacterial pathogen isolated from DFIs was S. aureus. To ensure effective treatment, accurate detection of MRSA is critical. Our findings showed that MRSA isolates had high-level resistance to antimicrobial agents and that appropriate antibiotic therapy, based on the antibiotic susceptibility pattern, is essential to ensure a good result.     

Managing foot infections in the older diabetic patient

The onset of a foot lesion can almost always be traced to an injury or trauma of some kind--physical, thermal, or chemical. Many are originally minor injuries that the patient, family, doctor, or other health professional considers trivial. Systemic indicators are frequently blunted in the elderly. Except in the most severe infections, elevations of temperature and white blood cell count may be absent, and frequently the only signs of ongoing infection are a slowly falling hematocrit and increasing difficulty of diabetic control.     

糖尿病足溃疡感染的诊治

糖尿病足溃疡感染的诊断依据是临床炎性表现,其感染严重程度分1～4级,常为多重需氧菌感染,厌氧菌可单独或联合作用.创面所处的环境、感染的类型和严重程度不同,其细菌学特点亦不同.糖尿病足溃疡感染需多学科综合治疗,包括外科治疗(清创、血管重建等)、使用抗生素或其他辅助治疗(如粒细胞集落刺激因子).有效治疗多能控制感染、降低截肢率.所以,糖尿病足溃疡感染需要明确诊断、有效治疗,从而改善预后.     

Advances in the treatment of diabetic foot infections

Lower extremity infections are frequent causes of substantial morbidity and mortality in the diabetic population, and these infections consume a large portion of resources expended on diabetic complications. Gram-positive cocci, particularly Staphylococcus aureus, are the most important pathogens in diabetic foot infections. These organisms are predominant both in mild infections (which are often monomicrobial), as well as in more severe and chronic infected wounds that more often have a polymicrobial cause. Appropriate clinical assessment and culturing of infections are critical in establishing the presence and severity of infection, in detecting osteomyelitis, and in directing the optimal treatment approach. Following necessary debridement and other surgical interventions (e.g., bone resection, revascularization), appropriate antibiotic therapy is a cornerstone of managing the infected lower extremity. Peripheral vascular (i.e., arterial) insufficiency and the increasing prevalence of antibiotic resistance are primary barriers to successfully managing these infections. Fortunately, alternative delivery systems (e.g., antibiotic beads, impregnated sponges) and novel antibiotics (e.g., levofloxacin, linezolid) are providing possible solutions to the challenges posed by this physically, emotionally, and financially devastating condition.     

Diagnosis and treatment of diabetic foot infections.

Prompt clinical diagnosis and timely treatment are the hallmarks of the proper care of diabetic patients with foot infections. The importance of careful clinical foot examination cannot be overemphasized. When infection is suspected, effort should be made to search for deeper infections, especially osteomyelitis. Numerous imaging techniques are available, but their cost-effectiveness has not been fully determined. Radiography of the foot is less sensitive but can provide useful information at a lower cost. Radio-isotope studies have not yielded consistent results, but the newer techniques deserve attention. Microbiological diagnosis should be attempted using only deep tissue culture, including bone biopsy. The primary aim of treatment of the infected foot is to restore ambulation. Timely surgical intervention and appropriate antimicrobial therapy can reduce the incidence of above-ankle amputation and reduce the length of hospital stay.     

糖尿病足溃疡的现代敷料应用选择

糖尿病足溃疡及其导致的截肢是糖尿病患者残废和死亡的主要原因之一.有数据显示,约15%糖尿病患者在他们的病程中会发生下肢溃疡[1-2],估计每年发病率为0.5%～3.0%[3-4],其中7%～20%的糖尿病足溃疡患者需要截肢,而糖尿病患者下肢截肢中则有85%是由足溃疡引起的[5-6].糖尿病足溃疡是难治性创面的一种.随着科技的发展和人们对糖尿病足溃疡认识的深入,出现了应用于各种不同状态创面的敷料,面对各种不同材质的现代敷料,许多未经专业培训的医务人员可能会感到无所适从,只好继续应用传统方法治疗,这也是众多现代敷料不能普及的原因之一.     

The diabetic foot infections: Biofilms and antimicrobial resistance

AimTo study the difference in antimicrobial resistance profile among biofilm producing and non-producing microorganisms isolated from diabetic foot ulcer in a tertiary care hospital in North India.MethodologyWe performed a prospective study on 162 DFU in patients treated in a multidisciplinary based diabetes and endocrinology center of JNMCH, AMU, Aligarh, India during the period of December 2008–March 2011. Detailed history and physical examination was carried out for every subject. Patient's profile, grade of DFU, co-morbidities and complications, laboratory data and final outcome were collected. Standard methods of sample collection and identification of microorganism were adopted. Risk factors for biofilm producing infections were determined by univariate analysis with 95% of CI. P value <0.05 were considered as significant.ResultsThe overall biofilm producing infection rate among DFU was 67.9%. On univariate analysis, significant risk factors for biofilm producing infection were male sex [P = 0.015, OR 2.35, RR 1.71], duration of diabetes [P < 0.006, OR 4.0, RR 2.7], duration of ulcer >1 month [P < 0.02, OR 2.26, RR 1.72], size of ulcer >4 cm² [P < 0.05, OR 2.03, RR 1.54], Grade II ulcer [P < 0.06, OR 1.87, RR 1.63], necrotic ulcer [P < 0.002, OR 5.79, RR 3.59], previous antibiotic use [P < 0.007, OR 4.24, RR 2.74], subcutaneous infection [P < 0.06, OR 1.87, RR 1.63], HbA1c >7% [P < 0.04, OR 3.19, RR1.87] and polymicrobial infection [P < 0.001, OR 6.64, RR 3.21] were significant risk factors.ConclusionsTreating the DFU by shifting from the planktonic model of microbiology to the biofilm model was recommended. With this new scientific approaches along with coordination of clinical and laboratory efforts, education, and research, it is possible to imagine overcoming much of biofilm disease.     

New developments in diagnosing and treating diabetic foot infections

Foot infections are common in persons with diabetes and are often the proximate cause of lower extremity amputation. There have been many publications in the past few years dealing with the appropriate ways to diagnose and treat diabetic foot infections. This review presents information gathered from a comprehensive, ongoing surveillance of the literature (published and abstracts) over the past 4 years. Prospective studies have now defined the epidemiology of diabetic foot infections, as well as methods to score and classify the wounds. Several recently published guidelines can assist clinicians in managing these infections. The etiologic agents of infection have been well-defined, and the prevalence of multi-drug-resistance pathogens is growing. Molecular methods offer great promise for quicker and more sensitive diagnosis of infection. New antimicrobial agents, both systemic and topical, as well as novel local treatments, have been shown to be effective in various studies. Improved methods of deploying older agents have added to the variety of treatment approaches now available. Several adjunctive treatments may benefit some patients but their role is as yet unclear. While there is much yet to learn about the most cost-effective ways to diagnose and treat diabetic foot infections the main effort is now to disseminate the available information and facilitate employing the evidence-based guideline recommendations.     

Nanotherapeutic approach to treat diabetic foot ulcers using tissue-engineered nanofiber skin substitutes: A review

Background and aimsDiabetes mellitus (DM) is a chronic metabolic disease associated with long-term multisystem complications, among which nonhealing diabetic foot ulcers (DFUs) are recognized as major cause of morbidity and mortality. Treating DFUs with surgical procedures such as synthetic or biological skin grafts or skin substitutes has several limitations, where none of the currently available skin substitutes is ideal.MethodsOVID/Medline and PubMed databases were searched using the Medical Subject Heading (MeSH) or Title/Abstract words (“diabetic foot ulcers”, “skin substitutes”, and “nanofibers”), to identify published research studies on DFUs and nanofibers.ResultsElectrospinning nanotechnology is being used in the biomedical field to produce polymeric nanofibers impregnated with drugs for wound healing, burns and diabetic ulcers. Those nanofibers also enable seeding of cells into them and culturing them in vitro to synthesize tissue-like structures. Knowing the advantages of generating patient-specific induced pluripotent stem cells (iPSCs) and organoids in three-dimension (3D), including skin organoids, it is worth mingling these technologies to develop tissue-engineered biological skin substitutes.ConclusionNanofiber-skin substitutes hold promise for treatment of patients suffering from DFUs and inspire novel strategies that could be applied to other organ systems as well, introducing a new era of “regenerative and personalized medicine”.     

Principles and practice of antibiotic therapy of diabetic foot infections

Foot infections are a common and serious problem in diabetic patients. They usually occur as a consequence of a skin ulceration, which initially is colonized with normal flora, and later infected with pathogens. Infection is defined clinically by evidence of inflammation, and appropriate cultures can determine the microbial etiology. Aerobic gram-positive cocci are the most important pathogens; in chronic, complex or previously treated wounds, gram-negative bacilli and anaerobes may join in a polymicrobial infection. In all diabetic foot infections a primary consideration is whether or not surgical intervention is required, e.g. for undrained pus, wound debridement or revascularization. Antibiotic regimens are usually selected empirically initially, then modified if needed based on results of culture and sensitivity tests and the patient's clinical response. Initial therapy, especially in serious infections, may need to be broad-spectrum, but definitive therapy can often be more targeted. Severe infections usually require intravenous therapy initially, but milder cases can be treated with oral agents. Treatment duration ranges from 1-2 weeks (for mild soft tissue infection) to more than 6 weeks (for osteomyelitis). The choice of a specific agent should be based on the usual microbiology of these infections, data from published clinical trials, the severity of the patient's infection, and the culture results. Extension of infection into underlying bone can be difficult to diagnose and may require imaging tests, e.g. magnetic resonance scans. Cure of osteomyelitis usually requires resection of infected bone, but can be accomplished with prolonged antibiotic therapy. Various non-antimicrobial adjunct therapies may sometimes be helpful. Published in 2000 by John Wiley & Sons, Ltd.     

Clinical and bacteriological survey of diabetic foot infections in Lisbon

Aims

An epidemiological survey of diabetic foot infections (DFIs) in Lisbon, stratifying the bacterial profile based on patient demographical data, diabetic foot characteristics (PEDIS classification), ulcer duration and antibiotic therapy.

Methods

A transversal observational multicenter study, with clinical data collection using a structured questionnaire and microbiological products (aspirates, biopsies or swabs collected using the Levine method) of clinically infected foot ulcers of patients with diabetes mellitus (DM).

Results

Forty-nine hospitalized and ambulatory patients were enrolled in this study, and 147 microbial isolates were cultured. Staphylococcus was the main genus identified, and methicillin-resistant Staphylococcus aureus (MRSA) was present in 24.5% of total cases. In the clinical samples collected from patients undergoing antibiotic therapy, 93% of the antibiotic regimens were considered inadequate based on the antibiotic susceptibility test results. The average duration of an ulcer with any isolated multi-drug resistant (MDR) organism was 29 days, and previous treatment with fluoroquinolones was statistically associated with multi-drug resistance.

Conclusions

Staphylococcus aureus was the most common cause of DFIs in our area. Prevalence and precocity of MDR organisms, namely MRSA, were high and were probably related to previous indiscriminate antibiotic use. Clinicians should avoid fluoroquinolones and more frequently consider the use of empirical anti-MRSA therapy.