Toxin‐Gene Profile Heterogeneity among Endemic Invasive European Group A Streptococcal Isolates

Abstract

We determined the toxin-gene profiles of 239 endemic, invasive group A streptococcal (GAS) isolates that circulated, within a 5-year period, in European university hospitals. Profiling was performed by use of multiplex polymerase chain reaction that screened for 9 streptococcal pyrogenic exotoxins (speA, speB, speC, speF, speG, speH, speJ, ssa, and smeZ). Analysis revealed that invasive GAS isolates do not share a common toxin-gene profile. Although all emm types were characterized by several different toxin-gene profiles, a predominance of 1 or 2 toxin-gene profiles could be observed, reflecting that a few invasive clones have spread successfully throughout the world. Remarkably, statistical pair-wise analysis of individual toxin genes revealed that strains that did not share the predominant profile still showed a nonrandom distribution of key toxin genes characteristic of the specific emm type. This could indicate that M proteins function, directly or indirectly, as barriers for horizontal gene exchange.

Distribution of Phage-Associated Virulence Genes in Pharyngeal Group A Streptococcal Strains Isolated in Italy

“…1). These latter genes were also frequently detected in previous works (13,20,21). The incidence of the other vir genes ranged between 3.7 and 14.4%.…”

“…The incidence of the other vir genes ranged between 3.7 and 14.4%. In the particular case of speA, its low prevalence contrasts with the significantly higher values (30 to 50%) reported in other works (13,15,20,21). The most prevalent resistance gene was mef(A) (73%) (Fig.…”

Prevalence of Streptococcus Invasive Locus ( sil ) and Its Relationship with Macrolide Resistance among Group A Streptococcus Strains

“…emm typing of GAS strains was performed by DNA sequencing according to the recommendations of the Division of Bacterial and Mycotic Diseases, the Centers for Disease Control and Prevention, and the emm sequence database (http: //www.cdc.gov/ncidod/biotech/strep/strepindex.htm). Multiplex PCR was used for toxin gene (speA, speB, speC, speF, speG, speH, speJ, ssa, and smeZ) profiling, as described by Schmitz et al (5). PCR detection of the sil locus was performed according to the method described by Bidet et al (1).…”

Host–Pathogen Interactions in Streptococcal Immune Sequelae

“…Only a few S. pyogenes strains lack the streptococcal cysteine proteinase SpeB (Darenberg et al, 2007;Schmitz et al, 2003;Vlaminckx et al, 2003), which is another suspected nephritogenic factor. SpeB and its zymogen zSpeB interact with plasminogen.…”