Electron microscopic findings for micafungin-treated experimental pulmonary aspergillosis in mice

We performed a scanning and transmission electron microscopic study on the efficacy of micafungin (MCFG) to understand what kind of damage MCFG causes to Aspergillus and to confirm its previously reported in vitro killing activity against Aspergillus in a mouse model of pulmonary aspergillosis. Aspergillus hyphae in MCFG-treated mice displayed hyphal burst, evidenced as either flattened or atrophied appearance and leakage of cellular contents after collapse of the cell wall. Thus, MCFG can induce the destruction of Aspergillus hyphae at the focus of infection. The results of the present study indicate that MCFG improves pulmonary aspergillosis due to lethal damage to Aspergillus hyphae. This action can effectively reduce the invasive ability of Aspergillus even though MCFG does not sterilize the fungal burden.