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Indian Journal of Medical Microbiology, Vol. 28, No. 2, April-June, 2010, pp. 164-166 Brief Communication Fungal infections in the soft tissue: A study from a tertiary care center *AJ Kindo, NS Rana, A Rekha, J Kalyani Departments of Microbiology (AJK, NSR, JK), Surgery (AR), Sri Ramachandra Medical college and Research Institute, Porur, Chennai - 600 116, India. Correspondence Address: *Department of Microbiology, Sri Ramachandra Medical college and Research Institute, Porur, Chennai - 600 116, India, anupmalakra@yahoo.com Date of Submission: 15-Jan-2009 Code Number: mb10048 PMID: 20404467 DOI: 10.4103/0255-0857.62498 Abstract Isolated fungal soft-tissue infections are uncommon but may cause severe morbidity or mortality, especially among immunosuppressed patients. In this study, a total of 56 soft-tissue specimens from patients with clinical suspicion of fungal infection collected at a tertiary care centre in Chennai during the period December 2005 to May 2007 were evaluated. Among the culture positives, majority were from diabetic patients. Among the 34 culture positives, the isolates consisted of Candida 12, Fusarium 4, Rhizopus 1 and Aspergillus 3 one each of Absidia corymbifera and Apophysomyces elegans. Treatment of fungal soft-tissue infection requires a team approach of surgeons, pathologists and microbiologists.Keywords: Fungal infection, immunosuppression, soft tissue introduction Introduction The spectrum of disease caused by fungus is diverse. It can be symptomatic or asymptomatic in most instances. Portal of entry for fungus is either through break in the skin or by respiratory tract. Introduction into body can occur by means of contaminated surgical instruments, intraocular lens, prosthetic device used in health care. [1] Individuals whose resistance is lowered typically suffer from invasive pulmonary or paranasal sinus infection, but in some instances the infecting fungus may spread to surrounding tissue or disseminate to any organ virtually. The opportunistic fungal disease includes aspergillosis, zygomycosis, cryptococcosis, and candidiasis. In addition to these, there are a number of rare infections caused by a variety of soil fungi. All these are able to grow or have optimum growth at body temperature. Material and Methods In this study, a total of 56 soft-tissue specimens from patients with clinical suspicion of fungal infection were collected at a tertiary centre in Chennai during the period December 2005 to May 2007. Factors like age, gender, underlying disease/immune status were taken into consideration. A clinico-mycological approach was taken in arriving at a diagnosis, correlating the clinical features with the laboratory findings. All samples irrespective of KOH positivity were subjected to fungal culture. Growth obtained was identified based on the macroscopic and microscopic morphology and other relevant tests as per standard procedures. [2] Results Demographics: Males were 31 (55.3%) and females 10 (17.85%); the ratio was 3:1. The age group among the study population ranged from 9 years to 72 years. Among the 56 samples received, 34 (61%) were culture positive for fungus (13 were repeat specimens). Among the culture positives, 13 were from diabetic patients, 3 patients had malignancy, 3 were suffering from tuberculosis, another 4 had cardiac problems, and 5 had other chronic illness, whereas 6 patients had no obvious cause of decreased immunity. Among the 34 culture positives, the isolates consisted of Candida spp 12, Fusarium spp 4, Rhizopus spp 1 and Aspergillus spp 3 one each of Absidia corymbifera and Apophysomyces elegans [Table - 1]. Discussion It is important for clinicians to be aware of fungal infections that may develop in the immunocompromised group. Candida spp was the major isolate; we had nine isolates of Candida tropicalis and one each of C. albicans, C. kefyr and C. guillermondi. In contrast to a study by Demet Kaya, the predominant organism was C. albicans total being 5, 3 were Candida tropicalis and 1 of C. guillermondi.[3] Species level identification is mandatory in high-risk patients as non-albicans strains are often resistant to antifungal agents. [3] We isolated four Fusarium solani from wound and pus. Colonies are woolly to cottony with cream to white aerial mycelium and a cream reverse. Hyphae are septate and hyaline. Macroconidia are moderately curved, stout, thick-walled, usually 3-5 septate. Chlamydoconidia are present (sometimes profuse) and occur both singly and in pairs. Infection caused by Fusarium species frequently involves skin, either as primary or metastatic site in the presence of certain predisposing factors such as excessive moisture, burn and immunosuppression. [4] Three of our patients were immunocompetent, whereas one patient was a diabetic In a study by English et al., they found skin lesion with Fusarium spp as the fungus isolated in more than 50% of patients as compared to other opportunistic fungi. [4] Among the immunocompetent hosts, skin lesions were localised, and responded well to the treatment . A. corymbifera is the only species of the genus Absidia recognised as a human pathogen . The colony is rapid growing, flat, woolly to cottony, matures within 4 days. The texture of the colony is typically woolly to cottony. A. corymbifera has wide (6-15 µm in diameter) non-septate hyphae. A few septa may occasionally be present. Rhizoids are rarely observed but not opposite the rhizoid. The sporangiophores are branched and arise in groups of two to five at the internodes. The sporangiophore widens to produce the funnel-shaped apophysis beneath the sporangium. The apophysis of A. corymbifera is very well developed and typical. It usually causes infection in immunocompromised patients as a result of inhalation or direct inoculation. A. corymbifera have been reported from rhinocerebral, cutaneous, pulmonary and disseminated infection . [5],[6] A. corymbifera can present with cutaneous infection with successful outcome if treated early. [5],[6] We isolated A. corymbifera with unusual presentation (as multiple discharging sinuses) from a diabetic patient. A. elegans is rare but medically an important member of the zygomycetes. A. elegans colonies are fluffy and cottony. It grows rapidly at 42°C. Hyphae are aseptate, rhizoid arises either between the points where the sporangiophores originate or opposite to the sporangiophores. The columella of A. elegans looks like a half circle and sporangia are pyriform (pear-shaped). It is known to cause cutaneous, subcutaneous and soft-tissue infection following trauma, burns or invasive procedure in apparently healthy host. Cases of cutaneous and subcutaneous A. elegans tend to be locally invasive. [7],[8] Our patient (a diabetic) sustained a road traffic accident and had facial cellulitis. Debrided tissue from the lesion grew A. elegans. Chakrabarti et al. diagnosed eight cases of zygomycosis due to A. elegans from August 1999 to September 2001. [9] In our study, one diabetic patient gave history of trauma, grew Rhizopus spp from soft tissue. The culture of Rhizopus sp typically resembled cotton candy. On the obverse, the colour of the colony was white initially and turned grey to yellowish brown in time. Rhizopus spp is non-septate or sparsely septate broad hyphae. Sporangiophores are brown in colour and usually unbranched. They can be solitary or form clusters. Rhizoids are located at the point where the stolons and sporangiophores meet. Primary cutaneous diseases with Rhizopus arrhizus and R. microsporus var. rhizopodiformis have been reported in association with the use of nonsterile adhesive bandages. [10] Spores were either introduced directly into the surgical wound or introduced into the traumatised skin at the time of bandage removal. Vesicular pustules, wound zygomycosis, gangrene, and necrotising fasciitis were all seen as part of these out-breaks. Primary cutaneous disease may occur following traumatic implantation of spores. Cutaneous mucormycosis is one of the recognised complications of extensive burns, diabetic acidosis and other specific immunocompromised conditions. Pulmonary aspergillosis is seen often in immunocompromised patients, but cutaneous aspergillosis occurs less frequently and is poorly characterised. Primary or secondary cutaneous aspergillosis have been reported in immunocompromised patients, like burn victims, neonates, individuals with cancer, and bone marrow and solid-organ transplant recipients. [11],[12],[13],[14] Aspergillus species isolated from soft tissue in our patients was Aspergillus niger (from lymph node biopsy in a patient with lymphoma) and Aspergillus fumigatus (from foot in a diabetic patient). Colonies of A. niger on potato dextrose agar at 25°C are initially white, quickly becoming black with conidial production. Microscopically, metulae and phialides cover the entire vesicle. Conidia are brown to black, very rough and globose. Colonies of A. fumigatus on potato dextrose agar at 25°C are smoky grey-green with a slight yellow reverse. Microscopically phialides (5-10 × 2-3 µm) are uniseriate, closely compact and occurring only on the upper portion of the vesicle. Conidia are smooth to finely roughened. Due to the timely diagnosis, most of the patients recovered after antifungal therapy except one patient who succumbed to the infection caused by A. elegans in spite of aggressive surgical treatment and amphotericin B. Fungal soft-tissue infections are increasing worldwide. The clinician should be aware of these opportunistic fungal infections for rapid diagnosis and treatment. References
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