Antifungal activities of moulds associated with selected stored grains and legumes.

An antifungal agent can either kill or inhibit the growth of fungi by interfering with the formation of fungal cell membrane, weakening it and hindering cell division. Antifungal agents of amphotericin B, ketoconazole, fluconazole and voriconazole of Thermo Fisher Scientific limited were used for this study. Cultural analysis of stored grains and legumes (rice, maize, wheat, groundnut and beans) from Imo State was done using streak plate method. Sabouraud dextrose agar was used for the culture while Mueller Hinton agar was used for Antifungal sensitivity test. Moulds were further identified using 18s rRNA gene sequencing method. The antifungal sensitivity profile of isolated and identified moulds was evaluated using the clinical laboratory and standard institute approved methods for testing of moulds, the disk diffusion and tetrazolium chloride test. The results showed that Aspergillus flavus, Aspergillus tamarii, Aspergillus niger, Aspergillus brunneoviolaceus and Penicillium chrysogenum were the moulds isolated and identified using both cultural and 18S rRNA sequence. The fungal isolates were susceptible to ketoconazole and voriconazole. Amphotericin B was both resistant and susceptible to different moulds. The fungal isolates were resistant to fluconazole. Inhibition effects were more with the antifungal disc than with tetrazolium salts. All the isolates were resistant to tetrazolium chloride and gave no zone of inhibition. Combination of antifungal agent and tetrazolium chloride showed sensitivity only to ketoconazole. Antifungal disc alone gave a better zone of inhibition than the combination of antifungal agents with tetrazolium salts. This study showed that ketoconazole has greater inhibitory potential than other antifungal agents. Ketoconazole remains the best drug of choice among the studied antifungal agents for fungal infections. Therefore antifungal drugs can be used against moulds of economic importance in the country. [ABSTRACT FROM AUTHOR]