EFFECT OF TISSUE INVASION AND TREATMENT WITH ITRACONAZOLE OR AMPHOTERICIN-B ON GALACTOMANNAN LEVELS IN PLASMA OF GUINEA-PIGS WITH EXPERIMENTAL INVASIVE ASPERGILLOSIS

The guinea-pig model of invasive aspergillosis was used to study the effect of the intensity of tissue invasion and of antifungal treatment on galactomannan levels in plasma. In untreated animals, galactomannan titres, determined with Pastorex Aspergillus, steadily increased and reached a maximum shortly before death. There was a significant correlation (P < 0.05) between this increase and that of the mean colony forming units of Aspergillus fumigatus in muscle, kidney, brain, peritoneum, eye and spleen, but not in skin, liver and lung. Pastorex Aspergillus detected galactomannan in 19/20 (95%) of the infected untreated animals. Uninfected guinea-pigs (160 samples) remained negative. In animals treated with itraconazole or amphotericin B, striking differences in antigenemia were observed between surviving and non-surviving animals. Only 5/25 surviving animals had detectable amounts of galactomannan in plasma, all on day 2 and one also on day 5, suggesting that successful treatment rapidly eradicated A.fumigatus or reduced the fungus to a level too low to release sufficient amounts of galactomannan. Antigenemia in treated non-surviving guinea-pigs resembled more closely the results in untreated animals. However, the number of positive animals (21/29 or 72.5%) was lower, suggesting that unsuccessful antifungal treatment could also affect levels of circulating galactomannan.