Catálogo de publicaciones - libros

As with other pathogens, the genome of can be subdivided into core and accessory segments, comprising roughly 75 and 25% of the genome. Particular attention is given to the MRSA252 strain, which is phylogenetically distinct from other genomes, is epidemic in the United Kingdom and North America, and is closely related to methicillin-susceptible clinical isolates that are hypervirulent in musculoskeletal infection models. This strain contains a number of unique or unusual small-scale variations compared with other genomes, and their potential significance as mediators of virulence is discussed. With respect to horizontally transferred virulence determinants of the core genome, another focus is to assess the integration sites of toxincarrying prophage, in terms of a potential cost-benefit relationship. The Staphylococcal Cassette Chromosome is discussed in terms of its role in promoting the evolution of antibiotic resistance, and as a potential mediator of genetic diversity and gene shuffling between species. The association of pathogenicity islands (SaPI) with temperate prophage is considered, with emphasis on a segment of the genome flanking the (coagulase) allele, and the diversity of SaPI content, such that there does not appear to be a single SaPI that is associated with the majority of virulent strains. The vSaoα and vSaβ genomic islands, which can be variable in composition, but common to all strains, are discussed in terms of how they may provide insight into the infection strategy of , and how vSaβ may be coevolving in association with antibiotic-resistant hospital-adapted strains.

Three species of bacteria in the genus are pathogenic for humans. and cause enteric diseases. causes the disease known as plague. Studies utilizing DNA hybridization and multilocus DNA sequencing show that and are closely related at the genetic level, while represents a distinct evolutionary lineage. It has been known for some time that , and encode homologous type III secretion system (TTSS) gene clusters on a common virulence plasmid. More recently, genome scale sequence analysis has revealed that and also encode homologous TTSS gene clusters on their chromosomes. In this chapter, we describe the genetic organization of TTSSs in and . We also describe several genetic changes in these TTSSs that have occurred during the evolution of and , and discuss the implications of these changes on our understanding of TTSS function during pathogenesis.

In this chapter, the complete genome sequence of the human pathogen Vibrio cholerae is examined. We discuss, in particular, the level of gene acquisition in the form of pathogenicity and genomic islands within the species, and the role of these elements in the various lifestyles of the organism This chapter will highlight the significant role horizontal gene transfer plays in the evolution, ecology, and virulence of V. cholerae-specific traits.

Sequencing of bacterial genomes and comparative genomics provide novel approaches for the identification of previously unrecognized microbial pathogens that likely cause a variety of infectious diseases in humans and animals. In addition, the genetic approaches probably will discover new virulence determinants that can be used as targets in the development of novel intervention strategies for both the prevention and treatment of infectious diseases. This chapter cites specific examples in support of these contentions, with particular reference to recent advances of selected infectious and chronic inflammatory diseases involving the gastrointestinal tract.