title: Understanding the association of Escherichia coli with diverse macroalgae in the lagoon of Venice.
abstract: Recent studies provided evidence that the macroalga Cladopohora in lakes hosts associated Escherichia coli, with consequences on the environmental and human health. We expanded these investigations to other macroalgae (Ulva spp., Sargassum muticum and Undaria pinnatifida) widespread in the lagoon of Venice (Italy). Attached E. coli were abundant, accounting up to 3,250 CFU gram(-1) of alga. Macroalgal-associated isolates belonged to all E. coli phylogroups, including pathogenic ones, and to Escherichia cryptic clades. Attached E. coli showed potential to grow even at in situ temperature on macroalgal extracts as only source of carbon and nutrients, and ability to produce biofilm in vitro. The genotypic diversity of the attached isolates was high, with significant differences between algae and the overlying water. Our evidences suggest that attached populations consist of both resident and transient strains, likely resulting from the heterogeneous input of fecal bacteria from the city. We report that cosmopolitan and invasive macroalgae may serve as source of E. coli, including pathogenic genotypes, and that this habitat can potentially support their growth. Considering the global diffusion of the macroalgae here studied, this phenomenon is likely occurring in other coastal cities worldwide and deserves further investigations from either the sanitary and ecological perspectives.
authors.affiliation: Institute of Marine Sciences (CNR - ISMAR), National Research Council, Venezia, Italy.
authors.forename: Grazia M
authors.initials: GM
authors.lastname: Quero
authors.affiliation: Department of Comparative Biomedicine and Food Science, University of Padova, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Fasolato
authors.affiliation: Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Vignaroli
authors.affiliation: Institute of Marine Sciences (CNR - ISMAR), National Research Council, Venezia, Italy.
authors.forename: Gian Marco
authors.initials: GM
authors.lastname: Luna
mesh_terms: D044822:Biodiversity; D018441:Biofilms; D017753:Ecosystem; D004926:Escherichia coli / Q000145:classification / Q000235:genetics; D014644:Genetic Variation; D007558:Italy; D060106:Lakes; D056265:Microbial Interactions; D012624:Seaweed