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

This study aimed to isolate antibacterial leads from a seaweed-associated bacterium. HeterotrophicBacillus amyloliquefaciens MTCC 12716 associated with the seaweedHypnea 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 againstPseudomonas aeruginosa, vancomycin-resistantEnterococcus faecalis,Klebsiella pneumoniae, methicillin-resistantStaphylococcus aureus, andShigella 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 aga inst methicillin-resistantS. aureus, vancomycin-resistantE. faecalis,Vibrio parahaemolyticus,Escherichia coli, andK. 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/...
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research