Spectrum and Prevalence of Fungi Infecting Deep Tissues of Lower-Limb Wounds in Patients with Type 2 Diabetes

Abstract

The prevalence rate and spectrum of fungi infecting deep tissues of diabetic lower-limb wounds (DLWs) have not been previously studied. Five hundred eighteen (382 male and 136 female) consecutive patients with type 2 diabetes hospitalized due to infected lower-limb wounds were enlisted in this study. Deep tissue (approximately 0.5-؋ 0.5-cm size) taken perioperatively from the wound bed was cultured for fungi. Fungi was found in 27.2% (141/518) of the study population. Candida parapsilosis (25.5%), Candida tropicalis (22.7%), Trichosporon asahii (12.8%), Candida albicans (10.6%), and Aspergillus species (5.0%) were the most predominant fungal isolates. Of the fungal isolates, 17.7% were resistant to itraconazole, 6.9% were resistant to amphotericin B, 6.9% were resistant to voriconazole, 3.9% were resistant to fluconazole, and 1.5% were resistant to flucytosine. Of the population, 79.7% (413/518) had bacterial infection in deep tissue. The predominant isolates were Enterococcus faecalis (14.1%), Staphylococcus aureus (12.2%), and Pseudomonas aeruginosa (10.8%). Mixed fungal and bacterial infections were seen in 21.4% of patients, while 5.8% had only fungal infection and 58.3% had only bacterial infections. Another 14.5% had neither bacteria nor fungi in the deep tissue. Patients with higher glycosylated hemoglobin levels had significantly more fungal infections. Our study reveals that deep-seated fungal infections are high in DLWs. In the context of delayed wound healing and amputation rates due to DLWs, it is important to study the pathogenicity of fungi in deep tissues of DLWs and their possible contribution to delayed wound healing. The role of antifungal agents in wound management needs to be evaluated further.Diabetes is now a worldwide epidemic. Among the 191 WHO member states, India has the highest number of people with diabetes (37). Fifteen percent of patients with diabetes develop lower-extremity ulcers during their lifetimes. Diabetes is the most common cause for nontraumatic amputation of lower extremities (1, 39). Eighty-five percent of these lowerlimb amputations are preceded by polymicrobial infections of the wound (23,26,36). Despite proper surgical and antibacterial therapy for infected diabetic lower-limb wounds (DLWs), the global long-term outcome of patients was found to be poor; only Ͻ50% of these patients had global therapeutic success (16,22).Fungal infections among immunocompromised patients are one of the major health concerns worldwide (5, 13, 19), but the spectrum of fungi infecting DLWs and their pathogenicity have not yet been studied thoroughly. Therefore, clinicians and surgeons treating diabetic foot wounds suspect only bacterial infections and treat them with antibacterial agents. They do not routinely send deep tissue from the wound bed for fungal culture and sensitivity, either due to lack of literature support or due to the assumption that there would not be any fungal infections in the DLWs. Surprisingly, our retrospective pilot study showed 27.9% positive fungal cultures in 3...

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