Novel amylomacins from seaweed-associated Bacillus amyloliquefaciens as prospective antimicrobial leads attenuating resistant bacteria

• Published in: World journal of microbiology & biotechnology 2021-12, Vol.37 (12), p.200-200, Article 200
• Main Authors: Chakraborty, Kajal, Kizhakkekalam, Vinaya Kizhakkepatt, Joy, Minju, Chakraborty, Rekha Devi
• Format: Article
• Language: English
• Subjects: Acetic acid; Algae; Ampicillin; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - metabolism; Anti-Bacterial Agents - pharmacology; Anti-Infective Agents - chemistry; Anti-Infective Agents - isolation & purification; Anti-Infective Agents - metabolism; Anti-Infective Agents - pharmacology; Antibiotic resistance; Antibiotics; Antimicrobial agents; Applied Microbiology; Bacillus amyloliquefaciens; Bacillus amyloliquefaciens - genetics; Bacillus amyloliquefaciens - isolation & purification; Bacillus amyloliquefaciens - physiology; Bacteria; Bacteria - drug effects; Biochemistry; Biomedical and Life Sciences; Biotechnology; Butyl acetate; Chloramphenicol; Chloromycetin; Cross Infection; Drug resistance; Drug Resistance, Bacterial - drug effects; E coli; Enterococcus faecalis - drug effects; Environmental Engineering/Biotechnology; Escherichia coli; Heterotrophic bacteria; Heterotrophic Processes; Homogeneity; Klebsiella; Klebsiella pneumoniae; Klebsiella pneumoniae - drug effects; Life Sciences; Methicillin; Methicillin-Resistant Staphylococcus aureus - drug effects; Microbial Sensitivity Tests; Microbiology; Minimum inhibitory concentration; Nosocomial infection; Original Paper; Peptide Synthases; Polyketide synthase; Polyketide Synthases; Polyketides; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Rhodophyta; Seaweed - microbiology; Seaweed - physiology; Seaweeds; Shigella flexneri - drug effects; Staphylococcus aureus; Staphylococcus infections; Vancomycin
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-021-03161-9

The rise in antibiotic-resistant bacterial strains prompting nosocomial infections drives the search for new bioactive substances of promising antibacterial properties. The surfaces of seaweeds are rich in heterotrophic bacteria with prospective antimicrobial substances. This study aimed to isolate antibacterial leads from a seaweed-associated bacterium. Heterotrophic Bacillus amyloliquefaciens MTCC 12716 associated with the seaweed Hypnea valentiae , was isolated and screened for antimicrobial properties against drug-resistant pathogens. The bacterial crude extract was purified and three novel amicoumacin-class of isocoumarin analogues, 11′-butyl acetate amicoumacin C (amylomacin A), 4′-hydroxy-11′-methoxyethyl carboxylate amicoumacin C (amylomacin B) and 11′-butyl amicoumacin C (amylomacin C) were isolated to homogeneity. The studied amylomacins possessed potential activities against Pseudomonas aeruginosa , vancomycin-resistant Enterococcus faecalis , Klebsiella pneumoniae , methicillin-resistant Staphylococcus aureus , and Shigella flexneri with a range of minimum inhibitory concentration values from 0.78 to 3.12 µg/mL, although standard antibiotics ampicillin and chloramphenicol were active at 6.25–25 µg/mL. Noticeably, the amylomacin compound encompassing 4′-hydroxy-11′-methoxyethyl carboxylate amicoumacin C functionality (amylomacin B), displayed considerably greater antagonistic activities against methicillin-resistant S. aureus , vancomycin-resistant E. faecalis , Vibrio parahaemolyticus , Escherichia coli , and K. pneumoniae (minimum inhibitory concentration 0.78 μg/mL) compared to the positive controls and other amylomacin analogues. Antimicrobial properties of the amylomacins, coupled with the presence of polyketide synthase-I/non-ribosomal peptide synthetase hybrid gene attributed the bacterium as a promising source of antimicrobial compounds with pharmaceutical and biotechnological applications. Graphic abstract