A Bacteriocin with Broad Antimicrobial Activity Produced by Newly Isolated Nitrogen-Fixing Bacillus Strains

Document Type : Original Article (s)

Authors

1 Department of Biology, School of Sciences, University of Isfahan, Isfahan, Iran

2 Professor, Department of Biology, School of Sciences, University of Isfahan, Isfahan, Iran

3 PhD Candidate, Department of Biology, School of Sciences, University of Isfahan, Isfahan, Iran

Abstract

Background: Recently re-emerging infections occur due to antibiotic-resistant bacteria. The use of bacteriocins as a substitute for currently used antibiotics is promising. The isolated nitrogen-fixing Bacillus bacteria might be a potential candidate strain as an alternative source of peptide antibiotics in the future. Methods: A total of 15 nitrogen-fixing Bacillus strains with antibacterial activity were isolated from soil samples. Bacteriocin-producing strains against the indicator strains were co-cultured and isolated. The antibacterial activity of bacteriocin was detected by spot-on-the lawn method with different bacteria. Effects of proteolytic enzymes, pH, and heat treatment on bacteriocin activity were also determined. Findings: All isolated spore forming Bacillus strains had an inhibitory effect on Listeria monocytogenes and Staphylococcus aureus. Some of them had an inhibitory effect on methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). None of them had an inhibitory effect on Gram-negative bacteria. The antimicrobial compounds produced by these novel strains were inactivated by the proteolytic enzymes which demonstrated their proteinaceous nature. These bacteriocins were also active in a wide range of pH and temperature. Conclusion: In the present study, new bacteriocin-producing nitrogen-fixing Bacillus strains with anti-MRSA and anti-VRE activity were isolated from the environment and their biochemical properties were determined. Keywords: Nitrogen-fixing Bacillus strains, Bacteriocin, Methicillin-resistant Staphylococcus aureus, Vancomycin-resistant Enterococcus faecalis
Journal of Isfahan Medical School
Volume 30, Issue 218 - Serial Number 218
November and December 2013
Pages 2260-2269

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History

  • Receive Date: 15 July 2012
  • Revise Date: 27 April 2024
  • Accept Date: 06 April 2022

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