Genome analysis of a multidrug-resistant Streptococcus sanguis isolated from a throat swab of a child with scarlet fever

A multidrug-resistant strain of the opportunistic pathogen Streptococcus sanguis (S28) was isolated from a throat swab of a child with scarlet fever as a rare case. Genome sequencing and analysis of strain S28 were performed to gain a better understanding of the multidrug resistance mechanisms of S. sanguis and its relationship with scarlet fever. The genome of S. sanguis S28 was sequenced on a Illumina HiSeq platform. Genome assembly was conducted using SOAPdenovo v.2.04 and the assembled genome sequence was submitted to NCBI for annotation. The 1 268 358 696bp genome of S. sanguis S28 contains 2287 coding sequences (CDS) with a GC content of 43.2%. Strain S28 possesses four antimicrobial resistance genes (ARGs), which is consistent with phenotypic analysis. A novel transposon with three genes conferring resistance to macrolide–lincosamide–streptogramin B (MLSB) antibiotics, tetracyclines and aminoglycosides was discovered. To our knowledge, this is the first report of a S. sanguis genome isolated from a throat swab of a child with scarlet fever and the first report of a transposon with three activated ARGs conferring resistance to MLSB, tetracyclines and aminoglycosides together.