taining 0.125 mg/ml Regadenoson site anidulafungin were stained with propidium iodide and Syto9 and compared with those cultured for 17 h on the same concentration or those shifted to zero anidulafungin after 14 h then grown for 3 h. In all cases lysed hyphal tips stained with propidium iodide. Furthermore, there was no evidence for extension of a lysed hyphal tip beyond the debris created by the lysis event. Similar experiments looking at recovery from 0.5 mg/ml caspofungin gave the same result. Therefore, there was no regrowth of lysed cells. Whilst microcolonies containing lysed cells clearly were recovering and growing, this was due to the growth of less damaged cells. This supports other lines of evidence that echinocandins are fungicidal for specific cells. Because of the overgrowth of lysed hyphae, it was not possible to conclude that lysed cells never recover, but it is likely that 20952447” this is not a common event. The interaction echinocandins. The between Cyclosporin A and immunosuppressive and calcineurin Microcolony Analysis of Aspergillus Discussion A. fumigatus was found to germinate, grow and produce conidia on a PAO support. Conidial germination and hyphal extension and microcolony growth appeared efficient on aluminium oxide, these parameters were similar to growth on agar. The addition of echinocandins allowed the effects of these drugs to be studied at the microscopic level, in microcolonies up to several hundred microns in diameter. As with other 
culture methods on PAO, imaging by fluorescence microscopy after staining with fluorogenic dyes or processing for SEM was facilitated by the inert support. This has advantages over previous microscopic studies of the effect of caspofungin on cells, with the ready addition and removal of reagents without disturbing the microcolony. Additionally, effective imaging was possible on the planar surface. This permitted relatively high throughput image processing and quantification compared to previous studies, which used liquid culture to investigate caspofungin and micafungin lethality. As far as we are aware, this is the first report of anidulafungin lethality. Caspofungin is the only echinocandin to have been studied both in liquid culture and on ” PAO. Broadly, the two studies reveal similar trends, with one exception. Lysis was most apparent on PAO at intermediate concentrations of caspofungin, i.e. those close to MIC values. Higher concentrations of both echinocandins limited microcolony growth to a greater extent but resulted in reduced lysis. This may be due to more rapidly growing cells being more vulnerable to lysis. Paradoxical growth has previously been described for A. fumigatus treated with echinocandins, i.e. when very high doses have a lesser effect on growth compared to intermediate dosage. Explanations of paradoxical growth often invoke compensatory mechanisms for limiting cell wall damage, such as the stimulation of chitin synthesis, which reduce drug effects at high concentrations. However, both at the microcolony pathway inhibitor cyclosporine A is known to have fungicidal activity for A. fumigatus. Cyclosporine has been shown to combine positively as an antifungal agent with caspofungin against some clinical isolates of A. fumigatus. Therefore, this interaction was tested on PAO. After 14 h culture on PAO, cyclosporine A induced rounded cells staining predominantly with Syto 9 when present at concentrations.3 mg/ml. At 3 mg/ml cyclosporine had little effect on cell morphology alone bu