emm gene diversity, superantigen gene profiles and presence of SlaA among clinical isolates of group A, C and G streptococci from western Norway

Abstract

In order to investigate molecular characteristics of beta-hemolytic streptococcal isolates from western Norway, we analysed the entire emm gene sequences, obtained superantigen gene profiles and determined the prevalence of the gene encoding streptococcal phospholipase A2 (SlaA) of 165 non-invasive and 34 contemporary invasive group A, C and G streptococci (GAS, GCS and GGS). Among the 25 GAS and 26 GCS/GGS emm subtypes identified, only emm3.1 was significantly associated with invasive disease. M protein size variation within GAS and GCS/GGS emm types was frequently identified. Two non-invasive and one invasive GGS possessed emm genes that translated to truncated M proteins as a result of frameshift mutations. Results suggestive of recombinations between emm or emm-like gene segments were found in isolates of emm4 and stG485 types. One non-invasive GGS possessed speC, speG, speH, speI and smeZ, and another non-invasive GGS harboured SlaA. speA and SlaA were over-represented among invasive GAS, probably because they were associated with emm3. speGdys was identified in 83% of invasive and 63% of non-invasive GCS/GGS and correlated with certain emm subtypes. Our results indicate the invasive potential of isolates belonging to emm3, and show substantial emm gene diversity and possible lateral gene transfers in our streptococcal population.

Adult Invasive and Noninvasive Infections Due to Streptococcus dysgalactiae subsp. equisimilis in France from 2006 to 2010

“…equisimilis infections in France are comparable to those previously described in other countries (21,22,23,24,25,26,27). Clinical isolates of S. dysgalactiae subsp.…”

“…equisimilis possessing Lancefield group A antigen have already been described (28,29). The 3 most prevalent invasive emm types (stG6, stG485, and stG6792) have been previously reported as the most common invasive emm types in other countries (stG6 in Finland, Israel, Norway, Taiwan, and the United States; stG485 in Finland, Israel, Japan, Norway, and Taiwan; stG6792 in Japan) (22,24,25,26,30,31). In these studies, the other most prevalent invasive emm types were stC839, stG10, stG245, stG480, stG643, stG840, and stG2078.…”

Clinical and molecular epidemiology of beta-hemolytic streptococcal infections in India

“…In our present study, the SDSE isolates recovered from fatal cases of septicemia did not carry any streptococcal superantigens. Based on our and a few other reports [18], it can be said that there is no clear-cut relationship between GCGS isolates harboring spe and disease severity, although this may be due to limited numbers of spe-positive isolates.…”

Soft tissue infection caused by Streptococcus dysgalactiae subsp. equisimilis possessing group Aantigen: a and review of the literature

“…There are, however, marked differences between them: SDSE, for example, lacks the whole set of genes encoding superantigens, which are mostly of phage origin (spe A, spe B, spe C, spe H, spe I, spe J, spe K, spe L, spe M, ssa, smez) [12,15,24,35,[38][39][40][41][42]. However, scarce occurrences of SDSE strains have been described, having one of those genes [32,43]. The only superantigen gene which is often found in SDSE strains is spe G, which encodes exotoxin G [12,22,24,32,35,36,[39][40][41][42]44].…”

“…However, scarce occurrences of SDSE strains have been described, having one of those genes [32,43]. The only superantigen gene which is often found in SDSE strains is spe G, which encodes exotoxin G [12,22,24,32,35,36,[39][40][41][42]44]. Between both of these closely related bacteria, interspecies DNA transfer occurs [6,45,46] by means of mobile genetic elements.…”