Prevalence And Biochemical Features of Melanized Fungi Isolated from Uli Community, Anambra State, Nigeria

Subcutaneous mycosis has been considered as mild infection previously but recent research has shown that several causative agents are highly pathogenic and could cause debilitating ailments if not properly checked. This study was conducted to evaluate the prevalence and biochemical features of melanized fungi isolated from Uli community, Anambra State, Nigeria. Two hundred and ten soil samples were collected from three communities (Umuoma, Umuaku, and Aluoha) at Uli community using soil auger. The soil samples were analyzed for the presence of melanized fungi using a standard microbiological technique followed by a prevalence enumeration of the fungal isolates using the same standard technique. The fungal isolates were characterized based on their cultural, microscopic, and biochemical features by measuring their ability to liquefy gelatin, hydrolyze skimmed milk, and utilize nitrate. Four black fungi were isolated from the three communities with variations in their occurrences (N=54). Umuoma community yielded the highest fungal isolate (22 (40.74%)) followed by Umuaku (20 (37.04%)) while the least was Aluoha (12 (22.22%)). The prevalence of the melanized fungi investigated was 31.48% and statistically, there was no significant difference (P=0.910) in the distribution of the fungal isolates in the three communities. Biochemically, Exophiala jeanselmei (88.2%) and Scedosporium apiospermum (85.7%) revealed high proteolytic activity and strong nitrate assimilation, Ochroconis mirabilis (58.3%) was moderate while Cladosporium (45.5%) showed weak proteolytic and moderate nitrate utilization. This study has shown that melanized fungi are moderately distributed in soils, and they exhibited high proteolytic activity, which indicates that they could be potent pathogens. However, further study is required to ascertain the in vitro and in vivo pathogenic potential of the melanized fungi in order to safeguard the health of individuals in the society, especially farmers in rural areas.