First record of Serratia marcescens from Adelie and Gentoo penguin faeces collected in the Wilhelm Archipelago, Graham Land, West Antarctica

Until recently, Antarctic animal species were thought to be safely isolated from human-associated infections. However, recent studies have shown that Antarctic penguins carry microorganisms, some of which are potential human pathogens. We investigated one rookery of Adelie penguins ( Pygoscelis adeliae ) and three rookeries of gentoo penguins ( P. papua ) for the presence of infectious diseases caused by non-indigenous microorganisms. Faecal samples were collected in the Argentine Islands (Wilhelm Archipelago, Graham Land), in the vicinity of the Ukrainian Antarctic Station "Akademik Vernadsky". Bacterial isolates obtained from the collected samples were identified as Serratia marcescens based on microscopic examination and biochemical studies. Additionally, partial sequences of the 16S rRNA gene were used to confirm the identity of the isolates. Phylogenetic analysis of the 16S rRNA partial gene sequences showed that all the obtained isolates belong to S. marcescens (rod-shaped Gram-negative bacteria), a species which has never been detected in Antarctic penguin faeces before.