Abstract
Background: Swine wastewater, a byproduct of intensive pig farming, is rich in organic matter and nutrients, creating an environment conducive to fungal proliferation.
Methods: Wastewater samples were collected from two locations: the Rivers State University piggery (Port Harcourt LGA) and a private farm in the Ipo community (Ikwerre LGA), Nigeria. Standard microbiological techniques were employed for fungal isolation, utilizing Potato Dextrose Agar (PDA) to promote fungal growth while inhibiting bacterial contamination. Following subculturing to obtain pure colonies, fungal identification was performed based on morphological characteristics, with lactophenol cotton blue staining used for microscopic examination. Antifungal susceptibility testing was conducted using the Kirby Bauer Disc Diffusion method, following Clinical and Laboratory Standards Institute (CLSI) M38-A2 guidelines, with isolates tested against Nystatin, Fluconazole, and Ketoconazole.
Results: The mean fungal counts were 2.5 ± 0.57 × 10² CFU/ml at the Ipo farm and 1.7 ± 0.21 × 10² CFU/ml at the Rivers State University farm. A total of eight fungal genera were identified: Aspergillus, Penicillium, Fusarium, Candida, Trichoderma, Alternaria, Rhizopus, and Mucor. Notably, Candida spp. and Rhizopus spp. demonstrated 100% susceptibility to all three antifungal agents tested. In contrast, Fusarium spp. showed complete resistance (0% susceptibility) across all agents, while Penicillium spp. exhibited resistance to Nystatin and Ketoconazole (100%) and intermediate susceptibility to Fluconazole (50%). Trichoderma spp. was resistant to both azoles tested (Fluconazole and Ketoconazole), with susceptibility only to Nystatin.
Conclusion: These findings highlight the presence of antifungal-resistant fungi in swine wastewater and emphasize the risk of environmental reservoirs contributing to the spread of resistance genes. This highlights the urgent need for sustainable antimicrobial use in agriculture, enhanced waste management practices, and the establishment of integrated surveillance systems to monitor resistance in both clinical and non-clinical settings.