title: Antimicrobial Activities of Bacteria Associated with the Brown Alga Padina pavonica.
abstract: Macroalgae belonging to the genus Padina are known to produce antibacterial compounds that may inhibit growth of human- and animal pathogens. Hitherto, it was unclear whether this antibacterial activity is produced by the macroalga itself or by secondary metabolite producing epiphytic bacteria. Here we report antibacterial activities of epiphytic bacteria isolated from Padina pavonica (Peacocks tail) located on northern coast of Tunisia. Eighteen isolates were obtained in pure culture and tested for antimicrobial activities. Based on the 16S rRNA gene sequences the isolates were closely related to Proteobacteria (12 isolates; 2 Alpha- and 10 Gammaproteobacteria), Firmicutes (4 isolates) and Actinobacteria (2 isolates). The antimicrobial activity was assessed as inhibition of growth of 12 species of pathogenic bacteria (Aeromonas salmonicida, A. hydrophila, Enterobacter xiangfangensis, Enterococcus faecium, Escherichia coli, Micrococcus sp., Salmonella typhimurium, Staphylococcus aureus, Streptococcus sp., Vibrio alginoliticus, V. proteolyticus, V. vulnificus) and one pathogenic yeast (Candida albicans). Among the Firmicutes, isolate P8, which is closely related to Bacillus pumilus, displayed the largest spectrum of growth inhibition of the pathogenic bacteria tested. The results emphasize the potential use of P. pavonica associated antagonistic bacteria as producers of novel antibacterial compounds.
authors.affiliation: National Institute of Marine Sciences and Technologies Salammbô, Tunisia.
authors.forename: Amel
authors.initials: A
authors.lastname: Ismail
authors.affiliation: National Institute of Marine Sciences and Technologies Salammbô, Tunisia.
authors.forename: Leila
authors.initials: L
authors.lastname: Ktari
authors.affiliation: Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research and Utrecht UniversityYerseke, Netherlands; Department of Microbiology and Molecular Genetics, University of the PunjabLahore, Pakistan.
authors.forename: Mehboob
authors.initials: M
authors.lastname: Ahmed
authors.affiliation: Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research and Utrecht University Yerseke, Netherlands.
authors.forename: Henk
authors.initials: H
authors.lastname: Bolhuis
authors.affiliation: Faculty of Mathematical, Physical and Natural Sciences of Tunis, Tunis El Manar University Tunis, Tunisia.
authors.forename: Abdellatif
authors.initials: A
authors.lastname: Boudabbous
authors.affiliation: Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research and Utrecht UniversityYerseke, Netherlands; Department of Aquatic Microbiology, Institute of Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, Netherlands.
authors.forename: Lucas J
authors.initials: LJ
authors.lastname: Stal
authors.affiliation: Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research and Utrecht University Yerseke, Netherlands.
authors.forename: Mariana Silvia
authors.initials: MS
authors.lastname: Cretoiu
authors.affiliation: National Institute of Marine Sciences and Technologies Salammbô, Tunisia.
authors.forename: Monia
authors.initials: M
authors.lastname: El Bour
keywords: Bacillus pumilus; Padina pavonica; antibiotics; epibionts; seaweed