Fungal detection in BALF
Overall, a positive BALF cytology was obtained in 18.1% (28/155) of all horses (Table 2).
Proportion of positive samples for fungi on cytological examination was significantly lower in the SA group than the MA group (P = 0.02) but not the CTL group (Table 2; Figure 1C).
No significant difference was found between CTL and MA groups. Proportions of fungi phagocytosed by macrophages and proportions of spores or hyphae (phagocytosed or not) were no significantly different between groups.
Overall, a positive BALF mycology was obtained in 23.9% (37/155) of horses. Proportion of positive samples for fungi by culture was significantly higher in the MA group than the CTL group (P = 0.008) (Figure 1D).
In BALF, 8 fungal genera were identified (Table S2), with the most commonly isolated genera being Aspergillus sp. (56.8%, 21/37), Aureobasidium sp. (27%, 10/37) andPenicillium sp. (21.6%, 8/37). Aureobasidium sp. was however not detected in any TW sample. Culture allowed identification of 6 species of Aspergillus sp., alone or in combination with other species: A. fumigatus (n=8), A. nidulans (n=7), A. glaucus (n=7), A. niger (n=3), A. versicolor (n=2) and A. terreus (n=1).
Aspergillus sp. was identified in 100% (3/3) of CTL horses, 55.6% (15/27) of MA horses and in 42.9% (3/7) of SA horses, with no significant difference between groups. Proportions ofAureobasidium sp. was not significantly different between groups; this genus was found in 33.3% (1/3) of CTL horses, in 33.3% (9/27) of MA horses and in 0% (0/7) of SA horses. Similarly, proportions of Penicillium sp. did not differ significantly between groups, with 0% (0/3) in CTL horses, 14.8% (4/27) in MA horses and 57.1% (4/7) in SA horses.