Occurrence of Nocardia in near shore marine environments and its public and environmental implications

Since 2003, large foaming events resembling ‘chocolate mousse-like foam’ have been reported along several popular beaches on the Sunshine Coast, Queensland, Australia, following storms and turbulent sea water events. Earlier studies at the University of the Sunshine Coast (UniSC) first highlighted that these foaming events contained an abundance of filamentous actinomycete species, specifically from the genus Nocardia. Species of this genus are frequently detected in the foams of sewage treatment plants during the activated sludge process. Nocardiae can form an extensive mycelial network and trap fats, oil and grease, which exacerbates foam formation. In addition, Nocardia species are known to be pathogenic and cause various diseases including nocardiosis in human and animal hosts. This review focusses on the occurrence, diversity and virulence properties of Nocardia species with examples of isolations of Nocardiae from foaming coastal marine waters of the region.