Evaluation of Antifungal Efficacy of Three New Cyclic Lipopeptides of the Class Bacillomycin from Bacillus subtilis RLID 12.1

Abstract

New lipopeptide homologues (AF, AF, and AF) with antifungal activities against and spp. were purified from a cell-free supernatant of RLID 12.1. The lipopeptides AF, AF, and AF were identified with the same peptide sequence Asn-Pro-Tyr-Asn-Gln-Thr-Ser with variations in the fatty acid branching type and chain length (-C, -C, and -C, respectively). Upon comparing the three homologues for MICs against 81 ( = 64) and ( = 17) clinical isolates and their cytotoxicities, we found that AF was the most promising antifungal lipopeptide, since it demonstrated 100% inhibition at geometric mean MICs of 3.31, 3.41, 3.48, and 2.83 μg/ml against ,, , and, respectively, with low hemolysis values (<6%) and 50% inhibitory concentrations (13.31 μg/ml). The additive effects among the homologues AF, AF, and AF were evaluated against three species, along with the cytotoxicity studies. Five combinations exhibited good additive interaction effects: AF/AF (at corresponding concentrations of 4 and 4 μg/ml [4/4 μg/ml]), AF/AF (4/4 μg/ml), AF/AF (2/4 μg/ml), AF/AF (4/4 μg/ml), and AF/AF (2/4 μg/ml) in planktonic cell inhibition and AF/AF (4/4 μg/ml), AF/AF (4/4 μg/ml), and AF/AF (2/4 μg/ml) in the inhibition of biofilm formation. However, combinations AF/AF and AF/AF, which showed >70% cell survival with low hemolysis (<5%), were found to be comparatively effective. We describe here the additive effects of lipopeptide homologues showing reduced cytotoxicity against mammalian cells; these combinations might serve as a potent antibiofilm-forming substitute.

Surfactin Like Broad Spectrum Antimicrobial Lipopeptide Co-produced With Sublancin From Bacillus subtilis Strain A52: Dual Reservoir of Bioactives

“…For commercial application of biologically active compounds, it is imperative to explore their toxigenic potential for the relevant applications. Though lipopeptides cause hemolysis (Inès and Dhouha, 2015;Greber et al, 2018;Ramachandran et al, 2018), surfactin-like lipopeptide in this study showed promising potential for topical applications as evident from the emulgel experiment. The gel showed antimicrobial activity and did not show any skin irritation effect during experiment with BALB/c mice.…”

Characterization and Synergistic Antimicrobial Evaluation of Lipopeptides from Bacillus amyloliquefaciens Isolated from Oil-Contaminated Soil

“…Polymyxin A is the example of lipopeptide with an antimicrobial activity which isolated from the soil bacterium Bacillus polymyxa [2]. Recently, several lipopeptides with diverse activities have been characterized, namely, as cytotoxic [3], antibacterial [4, 5], antifungal [6, 7], antiviral [8, 9], plant pathogenicity [10, 11], and anticancer [12, 13]. Some of them have been commercially used as an antibacterial drug such as daptomycin [14], caspofungin [15], micafungin [16], vancomycin, and teicoplanin [17].…”

Exploration of production of C14 and C15 bacillomycin D homologues with enzymatic hydrolysis from maize straws using fed-batch fermentation by Bacillus subtilis NS-174

“…The similar evidences were found in previous reports. 27,30 It was concluded that the antifungal compounds belonged to C 14 and C 15 of bacillomycin D homologues (C 14-15 BDs).…”