Distribution of Causative Microorganisms in Diabetic Foot Infections: A Ten-Year Retrospective Study in a Tertiary Care Hospital in Central Malaysia

Diabetes mellitus is a global pandemic, especially in Southeast Asia. Diabetic foot infection (DFI) is a common complication of this condition and causes significant morbidity and mortality in those affected. There is a lack of locally published data on the types of microorganisms and empirical antibiotics being prescribed. This paper highlights the importance of local microorganism culture and antibiotic prescription trends among diabetic foot patients in a tertiary care hospital in central Malaysia. This is a retrospective, cross-sectional study of data taken from January 2010 to December 2019 among 434 patients admitted with diabetic foot infections (DFIs) using the Wagner classification. Patients between the ages of 58 and 68 years old had the highest rate of infection. Pseudomonas Aeruginosa, Proteus spp., and Proteus mirabilis appeared to be the most isolated Gram-negative microorganisms, and Staphylococcus aureus, Streptococcus agalactiae, and MRSA appeared to be the most common Gram-positive microorganisms. The most common empirical antibiotics prescribed were ampicillin/sulbactam, followed by ciprofloxacin and ceftazidime, and the most common therapeutic antibiotics prescribed were ampicillin/sulbactam, ciprofloxacin, and cefuroxime. This study could be immensely pertinent in facilitating future empirical therapy guidelines for treating diabetic foot infections.

Evidence based review of literature on detriments to healing of diabetic foot ulcers

BACKGROUND

Diabetes mellitus places a substantial burden on society worldwide. Diabetic foot ulcers are a challenging problem for clinicians. Seven generally accepted detriments to healing of diabetic foot ulcers were identified: infection, glycaemic control, vascular supply, smoking, nutrition, deformity and offloading. The aim of this paper is to present a comprehensive evidence based review of the literature available on detriments to healing of diabetic foot ulcers.

METHOD

A research question was generated for each of the detriments to healing and a comprehensive review of the literature was performed using the Pubmed database in July 2014. All articles were assessed for relevancy and a level of evidence was assigned. An analysis of the total body of literature was used to assign a grade of recommendation to each detriment.

RESULTS

Grade A recommendation was assigned to offloading as there was good evidence supporting this intervention. Grade B recommendation was assigned to deformity as there was fair evidence consistent with the hypothesis. Infection and vascular supply had poor quality evidence supporting the research question and grade C recommendation was assigned. Grade I recommendation was assigned to glycaemic control, smoking and nutrition as there was insufficient and conflicting evidence available.

CONCLUSION

Our literature review revealed good evidence for some factors and insufficient literature on others. Further studies are needed to provide quality evidence regarding detriments to healing of diabetic ulcers.

Changes in Bacterial Profiles and Antibiotic Sensitivity Before and After Wound Bed Preparation for Diabetic Foot Ulcers

We aimed to investigate the characteristics of bacterial profiles and antibiotic sensitivity in diabetic foot ulcers before and after wound bed preparation. This study involved 423 diabetic patients with Wagner grades 1 to 4 foot ulcers. Secretion culture was performed before wound bed preparation. The observation endpoint was when the wound showed a tendency toward healing and a specialist determined that stopping antibiotic treatment would not affect wound healing. A second secretion culture was performed after the observation endpoint. We obtained results from both secretion cultures from 411 patients. The proportion of multi-drug-resistant (MDR) gram-positive bacteria was 22.0% and 47.8% before and after treatment, respectively; that for gram-negative bacteria was 3.5% and 19.2%, respectively (P < .05). Pretreatment antibiotic sensitivity of staphylococci and other gram-positive bacteria was 48.7% and 44.8%, respectively; the rates decreased significantly after treatment to 36.8% (P = .031) and 34.8% (P = .027), respectively. Pretreatment antibiotic sensitivity of common and nonfermenting rare gram-negative bacteria was 55.4% and 54.6%, respectively, which decreased substantially after treatment to 33.2% (P = .002) and 32.9% (P = .003), respectively. Wound healing was achieved in 92.7% of patients. Pretreatment and posttreatment C-reactive protein levels were 124.759 ± 71.58 mg/dL and 82.8 ± 53.61 mg/dL, respectively (P < .05). In conclusion, following wound bed preparation for diabetic foot ulcers, MDR bacteria numbers were increased and antibiotic sensitivity was decreased; inflammation was decreased. These findings warrant future studies for confirmation.

Nerve-Langerhans cell interactions in diabetes and aging

Cutaneous infections are a leading cause of hospitalization of diabetic patients. Langerhans cells (LCs) are antigen-presenting cutaneous dendritic cells that protect against infections, and effects of diabetes and aging on these cells are unclear. We examined LCs in footpads of rats with streptozotocin-induced diabetes at 3 months of age following 4 weeks of diabetes, and at 6 months following 16 weeks of diabetes. Immunostaining of LCs using the selective marker protein langerin showed cutaneous LC composition increased between 3 and 6 months of age owing to increased LC numbers and size in control rats. In diabetic rats, LC numbers increased with age but, unlike 6 month old controls, cell size did not, suggesting that diabetes impairs the increase in cell size that is a hallmark of LC maturation. Diabetes reduced LC numbers after 4 weeks and numbers and sizes following 16 weeks. We examined the relation between LC and innervation and found that, while axon density decreased with aging, it was not affected by 16 weeks of diabetes. However, LCs expressing the neuronal marker PGP9.5 represented a source of error in axonal counts. These findings support the hypothesis that diabetes substantially impacts LC proliferation and maturation independent of effects on cutaneous innervation. Accordingly, the interactions of diabetes and aging on LCs may be important factors in predisposing diabetic patients to cutaneous ulcers and infections.

The Etiopathogenesis of the Diabetic Foot: An Unrelenting Epidemic

Diabetes mellitus is a metabolic disease that is associated with hyperglycemia affecting various organ systems of the body. One of the most dreaded complications of this disease is the diabetic foot. The diabetic foot is the end result of multiple causal pathways, which include peripheral neuropathy and vascular disease. The problem is compounded by the increased incidence of infection. This article deals with the various pathogenic pathways associated with the development of the diabetic foot.