Exserohilum rostratum: Anatomy of a national outbreak of fungal meningitis

On 18 September 2012, an alert physician caring for a patient with fungal meningitis who had received an epidural methylprednisolone acetate injection approximately 6 weeks earlier, recognized its possible significance and reported this case to the Tennessee Department of Health, who in turn notified the Centers for Disease Control and Prevention. Shortly thereafter, additional cases of fungal meningitis were reported, and so began a large, unprecedented, multistate fungal meningitis outbreak. The predominant etiologic agent was Exserohilum rostratum, a black mould that was not known to have previously caused an outbreak of such devastating disease of this magnitude. The contaminated medication was prepared and distributed by a compounding pharmacy located in Massachusetts. This article reviews (i) the development and handling of the outbreak; (ii) the clinical manifestations and management of the infections; (iii) the detection, identification, and characteristics of E. rostratum, including the factors that might enhance its virulence; (iv) the regulatory concerns for microbiological quality control; and (v) what we have learned from this experience.