Subcutaneous mucormycosis caused by Rhizopus oryzae: probable nosocomial acquired infection

Abstract

SUMMARYThe Authors present a case of subcutaneous mucormycosis occurring in a patient with clinical and biochemical evidence of diabetic ketoacidosis. The clinical, mycological and histopathological features are described, emphasizing the relevance of a rapid diagnosis in order to stablish early treatment. The clinical forms of mucormycosis and the main associated conditions are briefly reviewed as well as the most probable conditions which may lead to the enhanced susceptibility to infection in the diabetic patient in ketoacidosis. The recovery of Rhizo¬ pus oryzae from the air of the room of the patient suggests a nosocomial infection acquired through contamination of venous puncture site by air borne spores. INTRODUCTIONThe human infections caused by fungi of the class Zygomycetes are cosmopolitan and have been reported in normal and immunocompromised hosts. The disease has been generically called Zygomycosis (Phycomycosis). GREER 12 suggested the terms Mucormycosis and Entomophtoromycosis to name the infections restrictly caused by Zygomycetes of the orders Mucorales and Entomophtorales, since they are different diseases 12 . The human mucormycosis is world-wide in distribution often as an opportunistic infection and rarely affecting immunologicaly normal individuals 18 . Frequently it is a disease of acute evolution, characterized by invasion and growth of Mucorales in the vascular wall and lumen, with subsequent mycotic thromboembolism, ischemia, tissue necrosis and eventually death depending on the effected site. The rhinocerebral variant is the most acute and fulminant of the known mycosis 21 .22. The entomophtoromycosis, also known as subcutaneous zygomycosis or basidiobolomycosis is restricted to tropical and subtropical regions, being reported the cases mainly from Africa and Asia, and occasionally from South America 5 . 13 . 18 . Generally it has a chronic evolution characterized by the development of eosinophilic granuloma in the subcutaneous fat, rhino-orbital cavities and other areas of the organism, with swelling of the affected regions. The patients are apparently healthy 6 . 18 . 19 .The agents of mucormycosis are ubiquitous in nature, where they live on decaying organic material as saprophytes. They may be isolated from the air, soil, fruits, clinical materials and human orifices 4 . They reproduce by sexual and asexual ways and in the anamorphic (asexual) state form a great amount of spores inside sacular structures called sporangia. The principal way of dissemination is the air. The primary or exogenous cutaneous and subcutaneous mucormycosis is a rare occurrence and the way of infection is related to the rupture of the skin barrier with subsequent development of necrotic lesions in the skin or subcutaneous iat i5 . 2i .Recently microepidemics of cutaneous mucormycosis were reported in hospitals and were related to the use of elasticized adhesive tape dressings on open wounds in immunocompromised patients 1U3 as well in patients with orthopedic problems and whithout apparent immunological c...