Microbiological and Cytological Analysis of Guttural Pouch Lavages Obtained from Apparently Healthy Thoroughbreds

To determine whether the guttural pouches in clinically healthy horses contain fungi, especially Emericella nidulans (E. nidulans) and Aspergillus fumigatus (A. fumigatus), that could possibly be pathogenic fungi, microbiological and cytological analyses were conducted. The results obtained were as follows: two fungal species, Eurotium sp. and Penicillium sp. were isolated from guttural pouch lavages in 1 and 2 out of 6 healthy horses respectively, whereas neither E. nidulans nor A. fumigatus were isolated. Eight species of bacteria were isolated from guttural pouch lavages in 1 to 6 cases, respectively. Staphylococcus xylosus was the most dominant species. The average number of nucleated cells in guttural pouch lavages was 0.89 ± 0.36 × 104 cells/ml. Most of the cells were cylindrical ciliated epithelial cells (82.4%). The findings suggest that the guttural pouches of clinically healthy horses contain a small number of fungi and bacteria, which normally reside in the equine environment and the ciliated epithelial cells in the organ may be related to the clearance of pathogenetic micro-organisms.