Enhanced nasopharyngeal infection and shedding associated with an epidemic lineage of emm3 group A Streptococcus. Issue 7 (3rd October 2017)

• Record Type: Journal Article
• Authors: Afshar, Baharak; Turner, Claire E.; Lamagni, Theresa L.; Smith, Ken C.; Al-Shahib, Ali; Underwood, Anthony; Holden, Matthew T. G.; Efstratiou, Androulla; Sriskandan, Shiranee
• Is Part Of: Virulence. Volume 8:Issue 7(2017)
• Page Start: 1390
• Page End: 1400
• Publication Date: 2017-10-03
• Subjects: DNases -- epidemic upsurge -- group A Streptococcus -- genotype emm3 -- invasive group A streptococcal disease -- nasopharyngeal infection -- prophage -- serotype M3 -- superantigens -- Streptococcus pyogenes; Virulence (Microbiology) -- Periodicals; Bacterial diseases -- Periodicals; Molecular microbiology -- Periodicals; 579.05
• DOI: 10.1080/21505594.2017.1325070
• Languages: English
• ISSNs: 2150-5608

Abstract

ABSTRACT: Background: A group A Streptococcus (GAS) lineage of genotype emm 3, sequence type 15 (ST15) was associated with a 6 month upsurge in invasive GAS disease in the UK. The epidemic lineage (Lineage C) had lost 2 typical emm 3 prophages, Φ315.1 and Φ315.2 associated with the superantigen ssa, but gained a different prophage (ΦUK-M3.1) associated with a different superantigen, speC and a DNAse spd1 .Methods and Results: The presence of speC and spd1 in Lineage C ST15 strains enhanced both in vitro mitogenic and DNase activities over non-Lineage C ST15 strains. Invasive disease models in Galleria mellonella and SPEC-sensitive transgenic mice, revealed no difference in overall invasiveness of Lineage C ST15 strains compared with non-Lineage C ST15 strains, consistent with clinical and epidemiological analysis. Lineage C strains did however markedly prolong murine nasal infection with enhanced nasal and airborne shedding compared with non-Lineage C strains. Deletion of speC or spd1 in 2 Lineage C strains identified a possible role for spd1 in airborne shedding from the murine nasopharynx.Conclusions: Nasopharyngeal infection and shedding of Lineage C strains was enhanced compared with non-Lineage C strains and this was, in part, mediated by the gain of the DNase spd1 through prophage acquisition.