Antibacterial Activity of Bioactive Compounds of Lumbricus Rubellus Earthworm-Ectosymbiotic Bacterium Peribacillus Butanolivorans KG, against Some Gram-Negative and Gram-Positive Pathogenic Bacteria

Abstract

Introduction: This study aimed to identify Lumbricus rubellus earthworm ectosymbionts bacteria as inhibitors of the growth of some pathogenic bacteria.

Methods: Fifty earthworms (Lumbricus rubellus) were collected from soil samples (5–15 cm) of agricultural farmland in Khorramabad City and were taken to the laboratory in sterile polypropylene bags. Bacteria were isolated from Lumbricus rubellus earthworms using nutrient agar. To assess the antimicrobial activity of the isolated strains, an agar well diffusion assay was performed against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The best isolate selected based on the zone of inhibition was subjected to further genus and species levels characterization by phylogenetic, morphological and biochemical methods.

Results: In this study, out of 14 isolated Lumbricus rubellus earthworm ectosymbionts bacteria, just one isolate demonstrate the ability to form an inhibition zone against all four pathogenic bacteria. Phylogenetic analysis utilizing 16S rRNA gene sequences facilitated the assignment of the analyzed bacteria to the genus Peribacillus. Following morphological and biochemical analyses also assigned the analyzed bacteria with the respective genus. The bacteria identified as Peribacillus butanolivorans KG, along with its genome sequence and its annotation information were submitted to the NCBI database by accession number OR229899. 1.

Conclusion: Antibacterial activity observed for Peribacillus butanolivorans KG within Lumbricus rubellus earthworm ectosymbionts bacteria reflects its potential as a source of new antibiotic agent