Objective: The aim of the present study was to isolate and identify mold species from poultry farms with detection of their virulence potential, biofilm formation capability and to perform antifungal susceptibility testing to some representative isolates.
Design: Observational study.
Animals: Fifty, freshly dead broiler chicks.
Procedures: A total of 250 samples were collected from 50 diseased chicks (5 samples each), including lung, liver, kidney, heart, and tracheal swap. In addition, litter samples were collected from 7 poultry farms and were subjected to mycological examination. The isolated mold species have been tested for hemolytic activity, catalase, amylase, lipase, and biofilm production activity; besides,  detection of virulence genes (rhbA, fos-1, and pskB) using PCR assay.  .
Results: A total of 208 mold isolates were identified, with five genera; Aspergillus (84.6%), Zygomycetes (12.9%), Acremonium (0.96%), Penicillium (0.96%) and Alternaria (0.48%). Mold isolates displayed various degrees of fungal activities on blood agar plates, catalase activity, amylase activity, lipase activity, and the ability for biofilm production in vitro. Regarding the selected virulence genes, fos-1 was detected in A.fumigatus (3 isolates) and A.flavus (2isolates).  While pksP gene was detected in A.fumigatus (7 isolates) and A.niger (2 isolates) and rhbA detected in A. fumigatus (8 isolates) and one isolate of A. flavus of the total evaluated species. The MIC determination provide evidence for the high resistance of all evaluated isolates to nystatin, and a relatively higher sensitivity was displayed by clotrimazole followed by ciclopiroxolamine and tioconazole.
Conclusion and clinical relevance: The results reveal that most of the fungal isolates tested displayed enzymatic activity, which are the most effective virulence factors contributing to fungal pathogenicity and high resistance to antifungal, which represents a potential public health concern.