Antifungal activity of native bacteria isolated from Khorramabad agricultural soil

Emergence of drug resistant strains and the limited use of antifungal drug due to possible toxic effects on humans, the high cost of their production and environmental pollution has made the search for novel bio-antifungal compounds a necessity. Microorganisms, particularly soil bacteria produce a wide range of active antimicrobial substances that some of them have antifungal properties. The purpose of this study is isolation and identification of the bacteria affecting the growth of fungi from Khorramabad agricultural soil.

Agricultural soils were collected from different areas of Khorramabad, Lorestan Province. The bacteria were isolated using nutrient broth and nutrient agar, then, the antifungal activity of their extracts and supernatant in the SCA media on several species of fungi was studied applying disk diffusion method.

Four strains showing a remarkable antifungal effect against some fungi, including Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus and Candida albicans. These isolates were identified by biochemical features and 16S rRNA sequence. Analysis of their sequencing through BLAST in NCBI data bank showed that these bacterial similarly closed to Pseudomonas sp. and Acinetobacter sp. genus.

This study was the first report of antifungal analysis of soil isolated bacteria from Khorramabad. These bacteria could be a potential candidate for biocontrolling pathogenic fungi.The extraction, identification and development of their inhibitory metabolites can be used in the design and production of antifungal agents.