Identifier: TDX:2840
Authors: Pérez Cataluña, Alba
Abstract:
The genus Arcobacter belongs to the family Campylobacteraceae and includes species considered emergent pathogens because they can produce infections in humans and animals. The species of the genus are widely distributed worldwide and the consumption of contaminated food or water is considered the source of the infection. There are several tools for the epidemiological characterization of the strains that could help to clarify the routes of infection. However, the mechanisms of action of these bacteria are still poorly understood and there is no standardized treatment. The number of species of the genus has increased considerably in recent years and the use of new isolation techniques has led to the discovery of other new species. In this thesis, it was demonstrated that the epidemiological analysis using the Multilocus Sequence Typing (MLST) technique is not precise. In addition, the high resistance to certain antibiotics suggested the need for introducing changes in the treatments used in Arcobacter infections. A total of 4 new species were described using phenotypic characterization, Multilocus Phylogenetic Analysis (MLPA) of 5 genes (atpA, gyrA, gyrB, hsp60 and rpoB) and information extracted from the sequenced genomes of these species and the phylogenetically close ones. The use of genomes and their comparison and phylogenetic analysis also showed that the species A. cryaerophilus is composed by 4 genomovars, which represent genomic species that could not be phenotypically differentiated. Finally, the phylogenetic analysis of the genomes of all the species of the genus, together with the calculation of different genomic indexes (ANI, isDDH, AAI, POCP and RSCU) allowed us to discover that the genus Arcobacter is actually formed by at least 7 genera, differentiable genetically and with a combination of phenotypic tests.
Repositori URV