Abstract
Fusarium solani, a mould normally associated with the biodeterioration of harvested crops and plants was identified as the species responsible for contamination and biodeterioration of an aqueous antacid formulation. The spoiled preparation was rendered vulnerable to opportunist pathogens during consumption and became implicated during several cases of infantile gastrointestinal infections. The Fusarium solani strain isolated was thought to be resistant to the antacid preservative system and capable of producing toxic metabolites during growth within the suspension. Experiments in submerged culture not only demonstrated the mould's resistance to the preservative Bronopol but highlighted its utilisation of the nitro group within that compound. Investigations failed to establish any links between this strain of Fusarium and the production of trichothecenes, however that it may become toxigenic under certain environmental conditions could not be ruled out. The action of the antacid suspension as a sporulation medium was assessed by examining the carbon/nitrogen ratio within the formulation and the effect individual ingredients had on the sporulation stimulus, this included monitoring the type of spores generated. The effects of pH on the induction of sporulation were also examined in shake flask culture. Members of the genus Fusarium can thus be directly involved in the biodeterioration (spoilage) of aqueous pharmaceutical suspensions. Their origin can be traced to damp conditions in the manufacturing environments of such products and are, therefore, not isolated to one specific manufacturing facility. Examination of other antacid suspensions has also indicated that this type of contamination, while not common, is certainly not rare. The reformulation of such products to preclude contamination by Fusarium solani would seem to be a necessary aspect of their future pharmaceutical development.