Activity of nasal amphotericin B irrigation against fungal organisms in vitro

The role of fungi in chronic rhinosinusitis has been described in recent reports. Controversy exists on the use of topical amphotericin B therapy as a treatment modality for this condition. The effect of various concentrations of amphotericin B nasal irrigation on actively growing fungi was studied in vitro.

Ten species of fungi commonly found in the nasal cavity were grown on growth media plates. Each fungi was exposed to 20 mL of amphotericin B nasal irrigation at concentrations of either 100, 200, or 300 microg/mL or sterile water two times daily for 6 weeks. Each plate was subcultured on a weekly basis to examine for any viable fungi.

Fungi growth was not arrested in the 100-microg/mL amphotericin B and sterile water groups at the end of 6 weeks. Use of the 300-and 200-microg/mL amphotericin B solutions showed failure of the subcultured fungi to grow at 5 and 6 weeks, respectively.

Nasal amphotericin B irrigation is ineffective in killing fungi in vitro at a concentration of 100 microg/mL over a 6-week period. Concentrations of 200 and 300 lig/mL successfully prevented fungi growth at the conclusion of the study. The current concentration of commercially available topical amphotericin B (100 microg/mL) seems ineffective in eradicating fungi in vitro.