Phenotypic and genotypic characterization of a novel multi-antibiotic-resistant, alginate hyperproducing strain of Pseudomonas mandelii isolated in Antarctica

Until recently, it was thought that Antarctica was a sterile continent due to extreme environmental conditions. In fact, this cold continent is one of the most diverse in terms of microorganisms. In the present study, the bacterial isolate Pseudomonas sp. 6A1 was obtained from marine sediments originating from the Fildes Peninsula Bay, King George Island, Antarctica. Subsequently, this isolate was identified as Pseudomonas mandelii. To arrive at this conclusion, molecular studies were performed using the 16S rRNA and multilocus sequence analysis. Both techniques were used to construct phylogenetic trees, revealing 99.99% similarity between the 6A1 strain and P. mandelii. To provide phenotypic support for this finding, BIOLOG GN2 and API20 NE tests, as well as assimilation assays with different carbon sources, were performed. These tests revealed 87% similarity with P. mandelii. This result was primarily due to an inability of the 6A1 strain to reduce nitrates, as well a s to variations in the assimilation of different carbon sources. Another important phenotypic difference was alginate hyperproduction by 6A1, a trait never before described in a P. mandelii strain. Finally, the 6A1 strain was found to present multiple antibiotic resistances. Altogether, these results confirm the first case of P. mandelii isolation from the Antarctic

Sustainable aquaculture through the One Health lens

Aquaculture is predicted to supply the majority of aquatic dietary protein by 2050. For aquaculture to deliver significantly enhanced volumes of food in a sustainable manner, appropriate account needs to be taken of its impacts on environmental integrity, farmed organism health and welfare, and human health. Here, we explore increased aquaculture production through the One Health lens and define a set of success metrics — underpinned by evidence, policy and legislation — that must be embedded into aquaculture sustainability. We provide a framework for defining, monitoring and averting potential negative impacts of enhanced production — and consider interactions with land-based food systems. These metrics will inform national and international science and policy strategies to support improved aquatic food system design