In January 2024, the study "Enterococcus montenegrensis sp. nov., isolated from artisanal Montenegrin dry sausage" was published in collaboration with the University of Donja Gorica, Montenegro, among others. The following AGES colleagues from the AGES Institutes of Medical Microbiology and Hygiene, Vienna and Veterinary Medicine, Mödling were involved in this project: Beatriz Daza-Prieto, Adriana Cabal, Patrick Hyden, Tobias Mösenbacher, Johann Ladstätter, Susanne Richter, Anna Stöger, Maria Joao Cardoso, Ali Chakeri, Petra Hasenberger, Silke Stadlbauer and Werner Ruppitsch.
This publication describes and characterises a newly discovered bacterial species, Enterococcus montenegrensis sp. nov., which was isolated from a traditional Montenegrin dry sausage.
Object of research
The researchers worked on a study to characterise the bacterial population of traditional dried Montenegrin sausages. The aim was to investigate the diversity of these bacterial populations and collect genetic information as a basis for deciding which bacterial strains can be used for future artisanal food production.
In the course of this study, a bacterium was isolated that could not be assigned to any known species. The new strain belongs to the genus Enterococcus and its name is Enterococcus montenegrensis.
Enterococcus montenegrensis
Enterococci are gram-positive, facultatively anaerobic microorganisms that belong to the group of lactic acid bacteria. They are widespread in the environment and play an important role in the fermentation of food. Despite their positive effects on health and long-standing use in food production, their use is controversial due to the development of resistance. The genus Enterococcus is not "generally recognised as safe" by the European Food Safety Agency, so each strain must be tested individually for resistance and virulence.
Analyses of the new strain
The strain CoE-012-22T isolated from dried beef sausage was cultivated on the culture medium "Columbia agar +5% sheep blood", purified and stored in glycerol at -80 °C. The strain was then submitted to the "German Collection of Microorganisms and Cell Cultures GmbH (DSM 115843T)" and the "National Collection of Industrial Food and Marine Bacteria (NCIMB 15468T)". Reference strains were also obtained from the "German Collection of Microorganisms and Cell Cultures GmbH (DSM 115843T)".
Phylogenetic analysis of the 16S rRNA gene showed that strain CoE-012-22T is closely related to other Enterococcus species, but nevertheless represents a new species.
In contrast to some reference strains, this strain does not carry any antibiotic resistance genes. No virulence genes or mobile genetic elements were found either. In the safety assessment, the strain was predicted to be non-pathogenic.
The strain E. montenegrensis CoE-012-22T possesses genes that are responsible for hydrolase activity and carbohydrate transport and are not found in other enterococci.
E. montenegrensis CoE-012-22T has a genome size of 2.80 MB. The G+C content of the DNA is 37.4 mol%.
In addition to the examination of the genome, biochemical tests and chemotaxonomic characterisation were also carried out.
Outlook
The newly discovered strain E. montenegrensis CoE-012-22T has unique genetic characteristics that distinguish it from other Enterococcus species. These characteristics could have beneficial effects on food.
The study is available at: Enterococcus montenegrensis sp. nov., isolated from artisanal Montenegrin dry sausage | Microbiology Society (microbiologyresearch.org)