Role of Conjugative Elements in the Evolution of the Multidrug-Resistant Pandemic CloneStreptococcus pneumoniae^Spain23FST81

Abstract

Streptococcus pneumoniae is a human commensal and pathogen able to cause a variety of diseases that annually result in over a million deaths worldwide. The S. pneumoniae Spain23F sequence type 81 lineage was among the first recognized pandemic clones and was responsible for almost 40% of penicillin-resistant pneumococcal infections in the United States in the late 1990s. Analysis of the chromosome sequence of a representative strain, and comparison with other available genomes, indicates roles for integrative and conjugative elements in the evolution of pneumococci and, more particularly, the emergence of the multidrugresistant Spain 23F ST81 lineage. A number of recently acquired loci within the chromosome appear to encode proteins involved in the production of, or immunity to, antimicrobial compounds, which may contribute to the proficiency of this strain at nasopharyngeal colonization. However, further sequencing of other pandemic clones will be required to establish whether there are any general attributes shared by these strains that are responsible for their international success.

Evaluation of phylogenetic reconstruction methods using bacterial whole genomes: a simulation based study

“…We used Artificial Life Framework v1.0 (ALF) 9 to simulate evolution along a given phylogenetic tree, using the 2 232 coding sequences in the Streptococcus pneumoniae ATCC 700669 genome 10 as the MRCA. As well as modeling SNP evolution, ALF also allows for short insertions and deletions (INDELs), gene loss and horizontal gene transfer events which occur in real populations but are usually not included in phylogenetic models.…”

Toxin-Antitoxin Genes of the Gram-Positive Pathogen Streptococcus pneumoniae: So Few and Yet So Many

“…The secondary structure seems to be more important than the base changes within the consensus sequence, as in certain cases, the BOX elements differ from the consensus, but the secondary structure remains the same (102). The BOX elements might enhance gene expression by either stabilizing mRNAs (e.g., increasing the half-life of the mRNA) or serving as DNA-binding sites for regulatory proteins (33,84). They are also probably involved in the regulation of virulence, genetic competence (84), and phase variation (132).…”

The influence of the accessory genome on bacterial pathogen evolution

“…47 Additionally, ICEs have a suggested role in evolution of multidrug-resistant Streptococcus pneumoniae Spain 23F ST81 lineage. 48 For example, the ICESpFST81 carries a tetM gene, responsible for the Spain 23F ST81 strain's tetracycline resistance. GIs are also important in the pathogenicity of plant pathogens: for example, Clavibacter michiganensis, a pathogen of tomato, contains a 129 kb island that is necessary for pathogenicity.…”