Molecular profile of scpA and sdaB virulence genes in Streptococcus pyogenes isolated from pharyngitis

Abstract

Group A Streptococci (GAS) or Streptococcus pyogenes is an important pathogen which causes a wide-ranging of diseases for human. This study was carried out in Ear Nose Throat (ENT) department in Al–Habboby Teaching Hospital, Thi-Qar province, south of Iraq during the period from October 2015 to April 2016. Two hundred and ten swabs were collected from patients infected with pharyngitis. 152 (72.3 %) showed positive growth with S. pyogenes. GAS isolates were subjected to detect two virulence genes (scpA and sdaB) by conventional PCR technique using specific primer pairs and DNA sequencing analysis. The sequencing of PCR products produced from bacterial DNA showed significant alignments identities (96-99%) to the S. pyogenes which are located in BLAST-NCBI Genbank. The six sequences of Streptococcus pyogenes scpA and sdaB genes determined in this study have been deposited in the GenBank under the accession numbers MF49318-MF497323. Phylogenetic analysis of S. pyogenes based upon the neighbour-joining of partial scpA and sdaB gene sequences showed that these sequences were derived from Streptococcal genes. In addition, S. pyogenes can produce several exotoxins that have the potential to damage the host tissues either directly or through the stimulation of cytokine production.