Reductive evolution in Streptococcus agalactiae and the emergence of a host adapted lineage.

ABSTRACT:

Background

During host specialization, inactivation of genes whose function is no more required is favored by changes in selective constraints and evolutionary bottlenecks. The Gram positive bacteria Streptococcus agalactiae (also called GBS), responsible for septicemia and meningitis in neonates also emerged during the seventies as a cause of severe epidemics in fish farms. To decipher the genetic basis for the emergence of these highly virulent GBS strains and of their adaptation to fish, we have analyzed the genomic sequence of seven strains isolated from fish and other poikilotherms.

Results

Comparative analysis shows that the two groups of GBS strains responsible for fish epidemic diseases are only distantly related. While strains belonging to the clonal complex 7 canno

SUBMITTER: Rosinski-Chupin I 

PROVIDER: S-EPMC3637634 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature