Nosocomial infection by Rhizomucor pusillus in a clinical haematology unit.

Three patients suffering from acute leukaemia were treated with cytotoxic agents and broad-spectrum antibiotics and received blood transfusion and nasal packing for severe epistaxis. All developed necrosis of nasal and facial tissues, with facial swelling an oedema; two biopsies showed typical phycomycete mycelium, and Rhizomucor pusillus was grown from one biopsy. Air and surfaces in the unit and the air intake and ducting were all heavily colonized by Rh. pusillus and other phycomycetes. It is suggested that Rh. pusillus spores from the air invaded the tissues in the conditions promoted by the nasal packing in these patients with impaired defences.