Diabetes mellitus is a major global health problem characterized by chronic hyperglycemia resulting from defects in insulin secretion, insulin action, or both.1 The prevalence of diabetes has increased substantially over recent decades, particularly in developing countries.2 Among the numerous complications associated with diabetes, diabetic foot ulcer (DFU) remains one of the most debilitating and costly conditions. It is estimated that approximately 15–25% of diabetic patients will develop a foot ulcer during their lifetime. Diabetic foot ulcers are associated with significant morbidity, recurrent hospital admissions, prolonged treatment, reduced quality of life, and an increased risk of lower-limb amputation.3,4 The development of diabetic foot ulcers is multifactorial and is primarily attributed to peripheral neuropathy, peripheral vascular disease, and impaired immune function.5 Neuropathy leads to loss of protective sensation, resulting in repetitive trauma and unnoticed injuries. Peripheral arterial disease compromises tissue perfusion, while hyperglycemia impairs leukocyte function and wound healing. These factors create an ideal environment for microbial colonization and infection, which further delays wound healing and increases the risk of tissue destruction.6 Infection is a major determinant of outcome in diabetic foot ulcers. Most studies and treatment protocols focus predominantly on bacterial pathogens because they are commonly isolated from infected wounds.7 However, fungal infections are increasingly being recognized as important contributors to chronic non-healing ulcers. Fungi may colonize ulcer surfaces or act as true pathogens, particularly in patients with longstanding diabetes, poor glycemic control, repeated antibiotic exposure, and prolonged ulcer duration.8 Failure to identify fungal involvement may result in persistent infection despite appropriate antibacterial therapy, leading to delayed healing and increased healthcare costs.9 Various fungal organisms have been isolated from diabetic foot ulcers, with Candida species being the most commonly reported pathogens. Other fungi such as Aspergillus, Trichosporon, Fusarium, and dermatophytes have also been identified in chronic wounds.10 The pathogenic role of fungi in diabetic foot ulcers is often overlooked because clinical manifestations are nonspecific and routine wound cultures are generally directed toward bacterial identification. Consequently, fungal infections may remain undiagnosed until ulcers become refractory to conventional treatment.11. Early recognition and identification of fungal pathogens can facilitate timely initiation of antifungal therapy and improve wound healing outcomes. Mycological evaluation of chronic or non-healing diabetic foot ulcers may therefore play an important role in comprehensive wound management. Understanding the prevalence and spectrum of fungal infections in diabetic foot ulcers can assist clinicians in developing appropriate diagnostic and therapeutic strategies. AIMS AND OBJECTIVES To determine the incidence of fungal infections in diabetic foot ulcers and to evaluate their association with demographic, clinical, and ulcer-related characteristics.

The present study was conducted as a prospective observational study in the Department of General Surgery at Sree Mookambika Institute of Medical Sciences, Kulasekharam. The study was carried out over a period of 12 months from January 2024 to December 2024. A total of 60 patients with diabetic foot ulcers attending the outpatient and inpatient services were enrolled after obtaining informed written consent. Ethical clearance was obtained from the Institutional Ethics Committee prior to commencement of the study. A detailed clinical history, including duration of diabetes, treatment history, glycemic control, duration of ulcer, and prior antibiotic exposure, was recorded for all patients. Inclusion criteria: Patients aged >18 years with type 1 or type 2 diabetes mellitus, clinically diagnosed diabetic foot ulcers of any grade, and those who provided informed written consent. Patients with chronic non-diabetic ulcers and those willing for follow-up were also included. Exclusion criteria: Citically ill or hemodynamically unstable patients, those receiving systemic antifungal therapy within the last 4 weeks, immunocompromised patients (HIV, malignancy, long-term steroid use), traumatic or arterial ulcers, unwilling participants, and pregnant or lactating women. All patients underwent thorough clinical examination, including assessment of ulcer characteristics such as size, depth, presence of discharge, signs of infection, and grading using Wagner’s classification. Routine laboratory investigations including complete blood count, fasting and postprandial blood glucose, HbA1c, renal function tests, and wound culture sensitivity were performed. For mycological evaluation, wound samples were collected from the base of the ulcer under strict aseptic precautions after proper cleaning and debridement. The samples were subjected to direct microscopic examination using potassium hydroxide (KOH) mount and fungal culture on Sabouraud dextrose agar for identification of fungal species. Data obtained were systematically recorded and entered into a master chart. Statistical analysis was performed using appropriate software, and results were expressed in terms of frequency, percentage, mean, and standard deviation. The association between fungal infection and clinical variables such as age, gender, duration of diabetes, glycemic control, and ulcer characteristics was analyzed, with a p-value of less than 0.05 considered statistically significant.

Most patients belonged to the 50 years and above category (60%), indicating higher prevalence of diabetic foot ulcers in older age groups. (Table 1). Table 1: Age Distribution of Study Participants Age Group (Years) Number of Patients Percentage (%) <40 10 16.7 40–49 14 23.3 50–59 18 30.0 ≥60 18 30.0 Total 60 100.0 Male patients were more commonly affected, reflecting higher exposure to risk factors and poorer foot care practices. (Table 2). Table 2: Gender Distribution Gender Number of Patients Percentage (%) Male 38 63.3 Female 22 36.7 Total 60 100.0 Fungal infection was identified in 8 (13.3%) patients based on KOH mount and culture positivity. The remaining 52 (86.7%) patients showed no evidence of fungal infection. (Table 3). Table 3: Prevalence of Fungal Infection Fungal Status Number of Patients Percentage (%) Present 8 13.3 Absent 52 86.7 Total 60 100.0 Fungal infection in diabetic foot ulcers demonstrated a significant association with multiple clinical and metabolic parameters. Patients with longer duration of diabetes (≥10 years), poor glycemic control (HbA1c >7%), higher Wagner grade (III–V), larger ulcer size (≥5 cm²), presence of neuropathy, peripheral vascular disease, and prolonged ulcer duration (≥4 weeks) showed a higher proportion of fungal positivity compared to their counterparts. All associations were statistically significant (p<0.05). (Table 4). Table 4: Correlation of Fungal Infection with Clinicopathological Characteristics Variable Category Fungal Infection Present (n=8) Fungal Infection Absent (n=52) p-value Duration of Diabetes <10 years 1 (12.5%) 24 (46.2%) 0.03 ≥10 years 7 (87.5%) 28 (53.8%) HbA1c Level ≤7% 1 (12.5%) 22 (42.3%) 0.04 >7% 7 (87.5%) 30 (57.7%) Ulcer Grade (Wagner) Grade I–II 2 (25.0%) 35 (67.3%) 0.02 Grade III–V 6 (75.0%) 17 (32.7%) Ulcer Size <5 cm² 2 (25.0%) 31 (59.6%) 0.05 ≥5 cm² 6 (75.0%) 21 (40.4%) Neuropathy Present 6 (75.0%) 18 (34.6%) 0.03 Absent 2 (25.0%) 34 (65.4%) Peripheral Vascular Disease Present 5 (62.5%) 15 (28.8%) 0.04 Absent 3 (37.5%) 37 (71.2%) Duration of Ulcer <4 weeks 2 (25.0%) 28 (53.8%) 0.04 ≥4 weeks 6 (75.0%) 24 (46.2%)

In the present study, fungal infection was detected in 8 (13.3%) patients, while 52 (86.7%) patients showed no evidence of fungal growth on KOH mount and culture. Majority of patients were older adults, with 36 (60.0%) patients aged 50 years and above. Male predominance was observed, with 38 (63.3%) males and 22 (36.7%) females. Similar demographic findings were reported by Kateel R et al.12 who observed a median age of 60 years with 68.3% male patients, and by Moslemi A et al.13 where the mean age was 62.1 years and 59% of patients were males. These findings indicate that diabetic foot ulcers are more common among elderly male patients, likely due to prolonged diabetes duration and cumulative vascular and neuropathic complications. The prevalence of fungal infection in the present study was 13.3%, which is comparable to the findings of Moslemi A et al.13 who reported Candida infection in 13% of deep tissue samples. Kalshetti VT et al.14 observed fungal culture positivity in 17.5% of diabetic foot ulcer patients, while Yadav S et al.15 reported fungal infections in 18% of cases. A comparatively higher prevalence of 21.3% was documented by Gopi A et al.16 whereas Kandregula S et al.17 reported fungal positivity in 31.7% of patients. The variability in prevalence across studies may be attributed to differences in patient characteristics, sampling techniques, ulcer severity, and microbiological methods. A significant association was observed between fungal infection and duration of diabetes. In the present study, 7 (87.5%) fungal-positive patients had diabetes duration of ≥10 years compared with 28 (53.8%) fungal-negative patients (p=0.03). Similar findings were noted by Moslemi A et al.13 who reported that more than 83% of patients had diabetes for over 10 years. Kateel R et al.12 also documented a median diabetes duration of 15 years among patients with diabetic foot ulcers. These observations suggest that prolonged exposure to hyperglycemia predisposes patients to chronic tissue damage and increases susceptibility to fungal colonization. Poor glycemic control emerged as another important factor associated with fungal infection. Among fungal-positive patients, 7 (87.5%) had HbA1c levels >7%, compared to 30 (57.7%) among fungal-negative patients (p=0.04). Moslemi A et al.13 found HbA1c levels >9% in 69% of patients and demonstrated a significant association between Candida infection and glycemic status. Similar observations by Yadav S et al.15 emphasized that persistent hyperglycemia creates a favorable environment for fungal growth and impairs host immune responses. These findings reinforce the importance of optimal glycemic control in preventing chronic wound infections. Ulcer severity and chronicity were significantly associated with fungal infection in the present study. Higher Wagner grades (III–V) were observed in 6 (75.0%) fungal-positive patients compared with 17 (32.7%) fungal-negative patients (p=0.02). Larger ulcers (≥5 cm²) and ulcers of longer duration (≥4 weeks) were also significantly associated with fungal positivity. Similar findings were reported by Moslemi A et al.13 who demonstrated a significant relationship between ulcer grade and Candida infection. Gopi A et al.16 found fungal positivity to be significantly associated with long-standing, non-healing Grade IV ulcers. Kandregula S et al.17 further emphasized the need for fungal culture in non-healing diabetic foot ulcers because fungal colonization may contribute to delayed wound healing and treatment failure. Neuropathy and peripheral vascular disease were significantly more common among fungal-positive patients. Neuropathy was present in 6 (75.0%) fungal-positive patients compared with 18 (34.6%) fungal-negative patients (p=0.03), while peripheral vascular disease was observed in 5 (62.5%) and 15 (28.8%) patients, respectively (p=0.04). Similar observations were reported by Kateel R et al.12 who identified neuropathy (35%) and peripheral vascular disease (23.3%) as major complications among diabetic foot ulcer patients. Moslemi A et al.13 documented neuropathic symptoms in 95% of their study population, emphasizing the crucial role of neuropathy in ulcer development and chronic infection. Devasia A et al.18 also reported peripheral vascular disease in 20% of patients with diabetic foot infections. Regarding fungal isolates, previous studies have consistently shown Candida species as the predominant organisms. Yadav S et al.15 reported non-albicans Candida as the most common fungal pathogen, followed by Candida albicans. Moslemi A et al.13 identified Candida parapsilosis and Candida albicans as the predominant isolates, whereas Kalshetti VT et al.14 reported Candida albicans as the most common species followed by Candida tropicalis. Similarly, Devasia A et al.18 isolated Candida tropicalis in all fungal-positive cases. These findings indicate that Candida species remain the principal fungal pathogens in diabetic foot ulcers.

Fungal infection in diabetic foot ulcers represents an important but often underrecognized complication associated with disease chronicity and severity. The study demonstrates a prevalence of 13.3%, with significant associations observed with poor glycemic control, longer duration of diabetes, higher Wagner grades, larger ulcer size, neuropathy, peripheral vascular disease, and prolonged ulcer duration. Demographic factors such as age and gender showed no significant correlation. These findings highlight that fungal colonization is more common in advanced and poorly controlled diabetic foot disease. Early identification and targeted antifungal therapy, along with optimal glycemic control and multidisciplinary foot care, may improve healing outcomes and reduce complications.

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