Marine macroalgae-associated heterotrophic Firmicutes and Gamma-proteobacteria: prospective anti-infective agents against multidrug resistant pathogens

Vinaya, K K and Chakraborty, Kajal (2020) Marine macroalgae-associated heterotrophic Firmicutes and Gamma-proteobacteria: prospective anti-infective agents against multidrug resistant pathogens. Archives of Microbiology, 202. pp. 905-920.

Archives of Microbiology_2020_Kajal Chakraborty_Marine macroalgae-associated heterotrophic Firmicutes.pdf

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    The development of drug-resistant bacteria and the necessity for unique antimicrobial agents, directed to the search of new habitats to screen the production of anti-infective substances. Culture-dependent studies of heterotrophic bacteria from the intertidal macroalgae thriving along the Southern coast of India resulted in the isolation of 148 strains, which were assayed for antibacterial activities against wide spectrum of pathogens including drug-resistant pathogens, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE). Two of the most active strains with a zone of inhibition ≥ 30 mm on spot over lawn assay, belonging to the phyla Firmicutes and Gamma-proteobacteria, isolated from a Rhodophycean marine macroalga, Hypnea valentiae, were selected for bioprospecting studies. They were further characterized as Shewanella algae MTCC 12715 and Bacillus amyloliquefaciens MTCC 12716, based on integrated phenotypic and genotypic analysis. The bacterial extracts exhibited significant antibacterial activities against MRSA and VRE with minimum inhibitory concentrations of 6.25–12.5 µg/mL. Time kill kinetic profiles of these bacteria revealed rapid bactericidal activity against both MRSA and E. coli, showing a ≥ 3log10 decline in viable cell count compared to the initial. In BacLight™ live/dead staining technique, the propidium iodide uptake results appropriately attributed that the components in the B. amyloliquefaciens extract might compromise the integrity of the cytoplasmic membrane of the pathogenic bacteria. Type-1 pks gene (MH157093) of S. algae and hybrid nrps/pks gene (MH157092) of B. amyloliquefaciens could be amplified. Antibacterial activity study combined with the results of amplified genes coding for polyketide synthase and nonribosomal peptide synthetase showed that these marine symbiotic bacteria had a promising broad-spectrum activity, and therefore, could be used against the emerging dilemma of antibiotic-resistant bacterial infections.

    Item Type: Article
    Uncontrolled Keywords: Marine macroalgae; Firmicutes; Gamma-proteobacteria; Anti-infective substances; Drug resistant pathogens; Nonribosomal peptide synthetase; Polyketide synthase; Bactericidal activity
    Subjects: Algae > Bacteria
    Biochemistry > Bioactive compounds
    Fish Biotechnology
    Fish Diseases
    Divisions: CMFRI-Kochi > Marine Biotechnology
    Subject Area > CMFRI > CMFRI-Kochi > Marine Biotechnology
    CMFRI-Kochi > Marine Biotechnology
    Subject Area > CMFRI-Kochi > Marine Biotechnology
    Depositing User: Arun Surendran
    Date Deposited: 21 May 2020 05:23
    Last Modified: 23 Nov 2021 09:32

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