Nosocomial infection with Rhizopus microsporus in preterm infants: association with wooden tongue depressors

Background We report four cases of cutaneous infection with Rhizopus microsporus in vulnerable preterm infants in one neonatal nursery. Methods There was no overlap in hospital stay between the first two cases and an extensive programme of environmental sampling was therefore initiated, with special attention being paid to items that had close contact with infantsʹ skin. Samples were cultured by standard techniques, including fungal culture with Sabouraudʹs medium. Filamentous fungi with non-septate hyphae were presumptively identified as agents of mucormycosis and referred to the Mycology Reference Laboratory, Bristol, UK, for speciation. Findings The source of infection was identified as wooden tongue depressors, which were used on the nursery to construct splints for intravenous and arterial cannulation sites. The outbreak was ended by the removal of these items from the nursery. Interpretation Wooden tongue depressors can be a vehicle for transmission of mucormycosis. The combination of warm, humid conditions in neonatal incubators, particularly in association with occlusive dressings, may favour cutaneous fungal invasion and put small, sick babies at risk of infection.