Detection of Streptococcus pyogenes virulence genes in Streptococcus dysgalactiae subsp. equisimilis from Vellore, India

Abstract

Streptococcus dysgalactiae subsp. equisimilis (SDSE), belonging to the group C and G streptococci, are human pathogens reported to cause clinical manifestations similar to infections caused by Streptococcus pyogenes. To scrutinize the distribution of gene coding for S. pyogenes virulence factors in SDSE, 255 isolates were collected from humans infected with SDSE in Vellore, a region in southern India, with high incidence of SDSE infections. Initial evaluation indicated SDSE isolates comprising of 82.35% group G and 17.64% group C. A multiplex PCR system was used to detect 21 gene encoding virulence-associated factors of S. pyogenes, like superantigens, DNases, proteinases, and other immune modulatory toxins. As validated by DNA sequencing of the PCR products, sequences homologous to speC, speG, speH, speI, speL, ssa and smeZ of the family of superantigen coding genes and for DNases like sdaD and sdc were detected in the SDSE collection. Furthermore, there was high abundance (48.12% in group G and 86.6% in group C SDSE) of scpA, the gene coding for C5a peptidase in these isolates. Higher abundance of S. pyogenes virulence factor genes was observed in SDSE of Lancefield group C as compared to group G, even though the incidence rates in former were lower. This study not only substantiates detection of S. pyogenes virulence factor genes in whole genome sequenced SDSE but also makes significant contribution towards the understanding of SDSE and its increasing virulence potential.

Evaluating the Diagnostic Paradigm for Group A and Non–Group A Streptococcal Pharyngitis in the College Student Population

“…The decision to treat NGAS remains a contentious topic in the field today, with limited study of the long-term effects of untreated NGAS infections to support protreatment advocates. A whole genome sequencing study of group C and group G streptococci (ie, NGAS) revealed virulence factor genes that were identical to those in GAS [ 14 ], hinting at potential interspecies exchange of virulence genes (ie, horizontal gene transfer). In addition to NGAS, Fusobacterium necrophorum , an anaerobic bacterial pathogen, has recently been recognized as an emerging pharyngitis pathogen of importance, particularly among young adults and adolescents [ 10 , 19 ]; however, this bacterium was not tested for in the present study as it is not currently included in the standard upper respiratory culture.…”

“…Despite that antibiotic therapy is only indicated for GAS [ 2 ], NGAS infections have also been reported to cause complications similar to GAS, including acute rheumatic fever and glomerulonephritis [ 13 ], though the incidence of such complications is unclear. Furthermore, there is evidence of shared gene content between GAS and NGAS species, including virulence factor genes for superantigens, DNases, proteinases, peptidases, and other immunomodulatory toxins [ 14 ], suggesting that some NGAS infections have comparable virulence to GAS infections.…”

Pathogenicity and drug resistance of animal streptococci responsible for human infections

“…The SDSD strains are assumed to belong to Lancefield group C and rarely L [119]. The SDSE strains can be classified as Lancefield group C or G [120]. However, SDSE typed as Lancefield group L or A have also been isolated [4,[121][122][123].…”

Prevalence and genomic characterization of Group A Streptococcus dysgalactiae subsp. equisimilis isolated from patients with invasive infections in Toyama prefecture, Japan

“…S. pyogenes and Lancefield Group A SDSE (ASD) are difficult to distinguish if MALDI‐TOF is not available in a clinical site. ASD was first reported in 1997, and it has been regarded as rare . SDSE AC‐2713, which was isolated in Germany, is the only strain with a reported genome .…”