title: Antibiofilm Activity of the Brown Alga Halidrys siliquosa against Clinically Relevant Human Pathogens.
abstract: The marine brown alga Halidrys siliquosa is known to produce compounds with antifouling activity against several marine bacteria. The aim of this study was to evaluate the antimicrobial and antibiofilm activity of organic extracts obtained from the marine brown alga H. siliquosa against a focused panel of clinically relevant human pathogens commonly associated with biofilm-related infections. The partially fractionated methanolic extract obtained from H. siliquosa collected along the shores of Co. Donegal; Ireland; displayed antimicrobial activity against bacteria of the genus Staphylococcus; Streptococcus; Enterococcus; Pseudomonas; Stenotrophomonas; and Chromobacterium with MIC and MBC values ranging from 0.0391 to 5 mg/mL. Biofilms of S. aureus MRSA were found to be susceptible to the algal methanolic extract with MBEC values ranging from 1.25 mg/mL to 5 mg/mL respectively. Confocal laser scanning microscopy using LIVE/DEAD staining confirmed the antimicrobial nature of the antibiofilm activity observed using the MBEC assay. A bioassay-guided fractionation method was developed yielding 10 active fractions from which to perform purification and structural elucidation of clinically-relevant antibiofilm compounds.
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, BT9 7BL Belfast, UK. a.busetti@qub.ac.uk.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Busetti
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, BT9 7BL Belfast, UK. tthompson08@qub.ac.uk.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Thompson
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, BT9 7BL Belfast, UK. dtegazzini01@qub.ac.uk.
authors.forename: Diana
authors.initials: D
authors.lastname: Tegazzini
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, BT9 7BL Belfast, UK. j.megaw@qub.ac.uk.
authors.forename: Julianne
authors.initials: J
authors.lastname: Megaw
authors.affiliation: School of Biological Sciences, Medical Biology Center, 97 Lisburn Road, BT9 7BL Belfast, UK. c.maggs@qub.ac.uk.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Maggs
authors.affiliation: School of Pharmacy, Queen's University Belfast, 97 Lisburn Road, BT9 7BL Belfast, UK. b.gilmore@qub.ac.uk.
authors.forename: Brendan F
authors.initials: BF
authors.lastname: Gilmore
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects*; D006801:Humans; D007494:Ireland; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal; D000459:Phaeophyceae / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents
keywords: Halidrys siliquosa; antibiofilm; antimicrobial; biodiscovery; clinical strains; extraction