a variable region within the genome of streptococcus pneumoniae contributes to strain-strain variation in virulence一个变量地区肺炎链球菌基因组内有助于strain-strain毒性的变化.pdfVIP

A Variable Region within the Genome of Streptococcus pneumoniae Contributes to Strain-Strain Variation in Virulence 1 1¤ 1 2 Richard M. Harvey , Uwe H. Stroeher , Abiodun D. Ogunniyi , Heidi C. Smith-Vaughan , Amanda J. 2 1 Leach , James C. Paton * 1 Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia, 2 Menzies School of Health Research, Charles Darwin University, Darwin, Northern Territory, Australia Abstract The bacterial factors responsible for the variation in invasive potential between different clones and serotypes of Streptococcus pneumoniae are largely unknown. Therefore, the isolation of rare serotype 1 carriage strains in Indigenous Australian communities provided a unique opportunity to compare the genomes of non-invasive and invasive isolates of the same serotype in order to identify such factors. The human virulence status of non-invasive, intermediately virulent and highly virulent serotype 1 isolates was reflected in mice and showed that whilst both human non-invasive and highly virulent isolates were able to colonize the murine nasopharynx equally, only the human highly virulent isolates were able to invade and survive in the murine lungs and blood. Genomic sequencing comparisons between these isolates identified 8 regions .1 kb in size that were specific to only the highly virulent isolates, and included a version of the pneumococcal pathogenicity island 1 variable region (PPI-1v), phage-associated adherence factors, transporters and metabolic enzymes. In particular, a phage-associated endolysin, a putative iron/lead permease and