Genome sequences of 113 S. agalactiae isolates using the Illumina technology

Streptococcus agalactiae or group B streptococcus (GBS) is a major cause of neonatal infections. It is also responsible for various diseases in immunocompromised adults and in the elderly. However, it is primarily a commensal colonizing 20 to 50% of the human population. It was initially described as responsible for bovine mastitis. Strikingly, neonatal infections due to GBS have emerged in the 60s both in Europe and in the US. In order to characterize the population structure of S. agalactiae strains isolated in humans and to identify the reasons for the emergence of GBS infections, we have determined, by using the Illumina technology, the genomic sequence of 113 S. agalactiae isolates. The majority of the strains were isolated in humans, in Europe and in three African countries between 1953 and 2010.