Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/9/2014
Publication Date: 9/9/2014
Citation: Bischoff, K.M., Leathers, T.D., Price, N.P., Manitchotpisit, P. 2014. Liamocin oil from Aureobasidium pullulans has antibacterial activity with specificity for species of Streptococcus [abstract]. Interscience Conference on Antimicrobial Agents and Chemotherapy. Poster F-976. p. 125.
Technical Abstract: The fungus Aureobasidium pullulans produces denser-than-water oils called liamocins. Liamocins have unique chemical structures with a mannitol head group linked to long chain polyester tails consisting of three, four or five 3,5-dihydroxydecanoic acid esters, some of which are O-acetylated. Broth dilution susceptibility testing determined that liamocin oil from A. pullulans NRRL 50380 possessed antibacterial activity against species of Streptococcus. Minimum inhibitory concentrations (MICs) ranged from =20 'g/ml to 78 'g/ml for the following species: S. agalactiae, S. uberis, S. mitis, S. infantarius, and S. mutans. Enterococcus faecalis was less susceptible (MIC = 312 'g/ml), while the following bacteria were not susceptible (MIC > 1250 'g/ml): Staphylococcus aureus, Lactobacillus fermentum, Escherichia coli, and Pseudomonas aeruginosa. Six other strains of A. pullulans produced oil with similar antibacterial activity. The liamocin components were separated by HPLC, and the fraction enriched for liamocin B1 (the non-acetylated type with four 3,5-dihydroxydecanoic acid groups) had the greatest antibacterial activity (MIC = 16 'g/ml). Treatment with 39 'g/ml liamocin reduced viability of S. agalactiae from 6.5 log (CFU/ml) to 4.5 log (CFU/ml) within 1 hour, suggesting that liamocin oil is bactericidal for S. agalactiae. Liamocins may be developed as a narrow spectrum antimicrobial agent that targets streptococcal pathogens but avoids disruption of the beneficial normal flora and reduces selection for antibiotic resistance in commensal bacteria.