Nocardia in Solid Organ Transplant Recipients

Nocardia species are ubiquitous environmental saprophytes, living in soil, organic matter and water (1). They are part of a heterogeneous subgroup of gram-positive bacteria informally designated as the ‘aerobic nocardiaform actinomycetes’; in addition to Nocardia, the organisms within this group which can cause human infection include Corynebacterium, Rhodococcus, Gordonia, Tsukamurella, Actinomadura and Mycobacterium (2,3). Although the exact number of valid Nocardia species is controversial, more than 50 have been characterized phenotypically and by molecular techniques (4).