Role of surveillance cultures in prevention and treatment of fungal infections.

Fungal surveillance cultures have been studied as potential predictors of invasive or disseminated mycoses. Several studies have demonstrated that the presence of Candida tropicalis in mucosal surveillance cultures has a high predictive value for invasive fungal infection due to this pathogen in granulocytopenic patients. By comparison, surveillance cultures for Candida albicans have a poor positive predictive value for invasive fungal infection. The value of routine surveillance cultures of the nares for Aspergillus spp. has not been consistently confirmed. The use of surveillance cultures for less common fungal pathogens, such as Trichosporon beigelii, also remains unclear. Fungal surveillance cultures of the inanimate hospital environment have proven useful in identifying the source of conidia in well-defined clusters or outbreaks of nosocomial aspergillosis and other mycoses. As investigational tools, fungal surveillance cultures also may be useful for studying the effects of new antifungal agents on mucosal flora. Fungal surveillance cultures, especially for C. tropicalis and possibly Aspergillus spp. in high-risk populations, may be useful when a pathogen-directed approach to antifungal therapy is used. However, the time required, diagnostic limitations, and expense of routine mucosal fungal surveillance cultures must be balanced against the effect of this information on therapeutic decisions. Empirical antifungal therapy and early diagnostic approaches for high-risk patients may obviate the need for routine fungal surveillance cultures while decreasing the frequency of invasive mycoses.