Isolation and identification of Rhizomucor pusillus from rhinofacial mucormycosis in a diabetic patient

Kiran Bala,Rishi Raj,Uma Handa,Rajpal Singh Punia,Jagdish Chander,Salil Aggarwal

doi:10.1099/jmmcr.0.002931

Abstract

Introduction: Mucormycosis is usually an invasive mycotic disease caused by fungi in the class Mucormycetes. It often occurs in immunocompromised patients but sporadic cases without apparent immune impairment have been described. Case presentation: Here we report a case of rhinofacial mucormycosis due to Rhizomucor pusillus in a 55‐year‐old diabetic female. She presented with diabetic ketoacidosis and nasal obstruction, nasal discharge and right‐sided cheek swelling following sinus surgery, which had been performed at a private hospital 1 month previously. Endoscopic biopsy was performed and the sample was sent for histopathological examination and KOH wet mount, which showed broad, pauci‐septate hyphae with right‐angle branching. The tissue was inoculated onto Sabouraud dextrose agar and white mycelial growth was obtained which turned grey with age. Morphological identification confirmed it as Rhizomucor pusillus. In vitro antifungal susceptibility testing was performed by means of the microbroth dilution method according to CLSI Approved Standard M38‐A. The isolate was found to be susceptible to amphotericin B, itraconazole and posaconazole but resistant to voriconazole and echinocandins. Functional endoscopic sinus surgery was performed and local necrotic tissue was debrided. The patient was put on liposomal amphotericin B, with a successful outcome. Conclusion: Early diagnosis is critical in prevention of morbidity and mortality associated with disease.

Highlights

Mucormycosis is usually an invasive mycotic disease caused by fungi in the class Mucormycetes
Various risk factors contribute to the development of mucormycosis, the most common being diabetes mellitus with ketoacidosis (Dokmetaset al., 2002)
Rhinoorbito-cerebral mucormycosis caused by R. pusillus was found only in 9 % of cases

Summary

Introduction

Mucormycosis is an invasive fungal infection caused by members of the order Mucorales. We here report the case of a 55-year-old diabetic female suffering from rhinoorbito-cerebral mucormycosis caused by R. pusillus. A 55-year-old female patient presented with a 1 month history of nasal blockage, nasal discharge, watering of eyes, right-sided facial swelling and loosening of teeth. On examination, she had purulent discharge in the right nasal cavity with small polyps. There was no history of any corticosteroid intake, iron therapy, haematological malignancy, trauma, transplantation, dialysis or intravenous drug intake Her blood sugar level (fasting) was 310 mg dl, haemoglobin 12.6 g dl, urea 12 mg dl, creatinine 0.93 mg dl and bicarbonate level 7 mmol l21. She was discharged in good condition with advice for regular follow-up

Findings

Discussion