Antibiogram and Molecular Detection of Aflatoxigenic Gene from some Species of Aspergillus in Cereal Grains

Abstract

Aflatoxins are potent mycotoxins produced by certain strains of Aspergillus, which pose significant threats to human and animal health due to their carcinogenic and mutagenic properties. The study therefore targeted the antibiogram and molecular detection of aflatoxigenic gene from some species of Aspergillus in Cereal grains. Seventy-two samples of maize, rice, wheat and millet were bought from different vendors in Mile 3, Mile 1 and Rumuokoro Market in Port Harcourt, Rivers State, Nigeria. The molecular characterization and detection of the aflatoxin regulatory gene was achieved using a PCR-based technique. The disc diffusion method was used in determining the antibiogram of the isolates. Data showed that the species were closely related to Aspergillus flavus strain HBF576, Aspergillus flavus strain AS25, Aspergillus niger strain A40, Aspergillus flavus strain 64-A1, Aspergillus flavus, A1S6_8 and Aspergillus flavus strain AKF-10. More so, thirteen (86.7%) of the fungal isolates had the aflatoxin regulatory gene. The antibiogram showed that 100% of A. flavus and A. niger were completely susceptible to nystatin while 95.45% of A. flavus and 100% of A. niger were susceptible to itraconazole. Fluconazole was however, the least potent antifungal agent. The presence of aflatoxin-producing Aspergillus bearing the aflatoxin regulatory gene could be a concern to the public, especially with the documented effect of aflatoxin on human health. The study indicated a high in vitro growth inhibition activity of nystatin, which could therefore serve as a potent antifungal agent in the control and management of infections associated with these fungal isolates in cereal grains.