Outbreaks of zygomycosis in hospitals

Zygomycosis refers to a group of uncommon and frequently fatal mycoses caused by fungi of the class Zygomycetes, the organisms of which are usually found in decaying organic matter. Disease can be transmitted by the inhalation of spores or by direct inoculation on disrupted skin or mucosa. For rare diseases such as zygomycosis, two or more cases occurring in a short time should be investigated as a probable epidemic. Twelve hospital outbreaks and two pseudoepidemics caused by Zygomycetes have been cited in the English literature. The first epidemic was recorded in 1977 and the last in 2008. Outbreaks have been reported in the USA, the UK and elsewhere in Europe. Cases have included cutaneous, disseminated, pulmonary and rhinocerebral disease. Species identified have included Rhizopus arrhizus, Rhizopus rhizopodiformis, Rhizopus microsporus, Rhizopus spp., Absidia corymbifera and Rhizomucor pusillius. Sources of infection have included Elastoplast adhesive bandage rolls, ventilation systems, wooden tongue depressors, karaya (plant-derived adhesive) ostomy bags, and water damage to a linen store and patient shower room. Patients have included cardiosurgery patients, renal transplant recipients, orthopaedic patients, adult leukaemia patients, intensive care unit neonates, immunocompromised haematology patients, and burn unit patients. Although zygomycosis outbreaks in the hospital environment are infrequent, a high index of suspicion should exist if necrotic lesions appear in proximity to a postoperative wound. Direct tissue examination and tissue culture and histopathology must be routinely performed.