Screening, Characterization and Optimization of Bioactive Peptides with Antibacterial Activities Against Multi-Drug Resistant Pathogens, Produced by Bacillus safensis Strain MK-12.1

• Published in: International journal of peptide research and therapeutics 2022-11, Vol.28 (6), Article 161
• Main Authors: Iqbal, Sajid, Begum, Farida, Qasim, Muhammad
• Format: Article
• Language: English
• Subjects: American Type Culture Collection; Animal Anatomy; Antibacterial activity; Antimicrobial resistance; Bacillus; Bacillus safensis; Bacteria; Biochemistry; Biomedical and Life Sciences; Fermented food; Histology; Life Sciences; Metabolites; Molecular Medicine; Molecular weight; Morphology; Multidrug resistance; Pathogens; pH effects; Pharmaceutical Sciences/Technology; Pharmacology/Toxicology; Polymer Sciences; rRNA 16S; Strains (organisms); Toxicity
• ISSN: 1573-3904; 1573-3149; 1573-3904
• DOI: 10.1007/s10989-022-10469-z

Antimicrobial resistance in pathogenic bacteria is increasing rapidly. Therefore, investigation of novel therapeutic agents are essential to combat the growing multidrug resistance (MDR) in human pathogens. The current study was intended to identify antibacterial metabolites producing Bacillus spp. from the unexplored southern region of Pakistan . The bacterial isolates ( n  = 47) were isolated from soil samples and screened for antibacterial activity against a set of American Type Culture Collection (ATCC) and MDR human pathogenic bacterial strains. Among all isolated Bacillus spp. the strain MK-12.1 exhibt promising antibacterial activities agains all tested strains. The antibacterial metabolites from MK-12.1 were partially extracted and their molecular weight and toxicity were evaluated. Genomic DNA was extracted from a fresh culture of antibacterial metabolite-producing strain MK-12.1, and the 16S rRNA gene was amplified and sequenced. The growth and antibacterial metabolites production by MK-12.1 was optimized at various pH, temperature, incubation time, and medium. The strain MK-12.1 efficiently inhibit the growth of ATCC as well as MDR pathogenic bacterial strains with the zone of inhibition ranges from 14 to 18 mm. The partially extracted antibacterial compound was characterized and confirmed to be proteinogenic, non-hemolytic, and molecular weight was less than 20 kDa. The isolate MK-12.1 was identified as Bacillus safensis and revealed 99% similarity with B. safensis strain NBRC. Maximum antagonistic activity and growth of MK-12.1 were observed at pH 8, 30 °C temperature, and 48 h of incubation in a shaking incubator when fermented in an optimized (opt) medium. The current study results indicate that B. safensis MK-12.1 produces promising antibacterial compounds that could be a source of new antibacterial leads to fight against MDR bacteria in future.