Antimicrobial Activities and Chemical Profiles of Fungal Species Isolated from Bovine Dung in the North West Region of Cameroon

Abstract

The global rise of drug-resistant pathogens has intensified the challenge of antimicrobial resistance, rendering many conventional antibiotics ineffective against infectious diseases. Coprophilous fungi are saprophytic fungi that live on animal dung and are recognized as promising sources of bioactive compounds, including antibiotics, enzymes, and biocontrol agents. This study aimed to document the diversity of fungi from cow dung samples collected in the Mezam Division, North West Region of Cameroon, to evaluate the antimicrobial activity of their crude extracts, and annotate compounds in the most active crude extracts. A total of 100 fungal isolates were recovered from 21 dung samples sourced from three cattle ranches using the moist chamber technique. Based on morphological characteristics, 12 representative strains were selected and identified through the internal transcribed spacer (ITS) gene region. Ethyl acetate extracts from solid-state cultures of these strains were screened for antimicrobial activity against available in‑house strains, including Escherichia coli, Staphylococcus aureus, and Candida albicans, using the microdilution method. Metabolite annotation of these active extracts was performed using Ultra‑High Performance Liquid Chromatography – Quadrupole Time‑of‑Flight – Electrospray Ionization – Tandem Mass Spectrometry (UHPLC-QTOF-ESI-MS/MS). The extracts displayed variable antimicrobial activity, with minimum inhibitory concentrations (MICs) ranging from 125 to 1000 µg/mL. Notably, crude extracts of Scopulariopsis brevicaulis, Papulaspora gansuensis, Clonostachys epichloe, and C. rosea demonstrated the most promising activity (MICs 125–500 µg/mL). Metabolite profiling revealed diverse chemical constituents, including uridine, spiroxamine, adipic acid, and sebacic acid, which have been previously reported for their antimicrobial properties. These findings highlight coprophilous fungi as a rich source of structurally diverse metabolites with potential relevance for drug discovery against microbial pathogens.