An antimicrobial metabolite n- hexadecenoic acid from marine sponge-associated bacteria Bacillus subtilis effectively inhibited biofilm forming multidrug-resistant P. aeruginosa

Abstract

Effective drug candidates to obstruct the emergence of multidrug-resistant pathogens have become a major concern. A potent antimicrobial producer was isolated from a marine sponge designated as MSI38 and was identified as Bacillus subtilis by 16SrDNA sequencing. The active antimicrobial fraction was purified, and the metabolite was identified as n-hexadecanoic acid by spectroscopic analysis. The fish-borne pathogen Pseudomonas aeruginosa FP012 was found to be multidrug-resistant and poses a risk of disease to food handlers and consumers in general. The compound showed a potent bactericidal effect against P. aeruginosa FP012 with a MIC of 31.33 ± 5.67 mg L⁻¹ and MBC of 36.66 ± 5.17 mg L⁻¹. The time-based biofilm inhibitory potential of MSI38 and ciprofloxacin was analyzed by confocal laser scanning microscopy. A synergistic effect of MSI38 and ciprofloxacin on biofilm showed 85% inhibition.

Keywords:

• n- hexadecanoic acid
• antimicrobial activity
• marine sponge
• biofilm
• multidrug-resistant

Ethical approval

Compliance with Ethical Standards Research Involving Human Participants and/or Animals No human and animal participants are involved.

Author contributions

AS performed the experiments, AR, PR performed data analysis, GSK designed the experiments, and JS designed the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data Availability statement

The data that support the findings of this study are available with the corresponding author.

Additional information

Funding

GSK is thankful to Department of Science and Technology for the grant and JS is thankful to the Department of Biotechnology, Govt. of India for the project.