Epidemic of Group AStreptococcusM/emm59 Causing Invasive Disease in Canada

Abstract

Western Canada has witnessed the rapid emergence of a rare GAS strain causing invasive disease predominately in a select population of disadvantaged persons.

High Incidence of Invasive Group A Streptococcus Disease Caused by Strains of Uncommon emm Types in Thunder Bay, Ontario, Canada

“…In 2008, Thunder Bay experienced a marked increase in iGAS notifications, followed by the declaration of a local outbreak of emm59 iGAS that was inscribed in the context of a large Canadian emm59 epidemic characterized by a high rate of skin and soft tissue infections (5,6,8). Retrospective analysis found that the incidence of iGAS disease in Thunder Bay had been greater than the provincial average since 2007, while in previous years it had been comparable to that observed in the metropolitan region of Toronto/Peel and in line with rates for the province of Ontario.…”

“…More than 240 GAS emm types are recognized based on the sequence of the hypervariable 5= end of gene emm, encoding M protein, a major GAS virulence factor with antiphagocytic properties (2)(3)(4). Beginning in 2006, Canada experienced an epidemic of invasive GAS (iGAS) infections caused by strains of the previously rare emm59 type (5). A hypervirulent clone, which later disseminated to several areas of the United States, was shown to be responsible for hundreds of cases countrywide (6)(7)(8)(9)(10).…”

“…A hypervirulent clone, which later disseminated to several areas of the United States, was shown to be responsible for hundreds of cases countrywide (6)(7)(8)(9)(10). Invasive type emm59 strains were frequently isolated from soft tissue infections and were recovered in higher percentages from patients with distinctive risk factors, including alcohol abuse, homelessness, hepatitis C virus (HCV) infection, and intravenous drug use (IVDU) (5,6). In the province of Ontario, most emm59 iGAS infections occurred in Thunder Bay, the most populous municipality in the Northwestern area of the province (population, approximately 110,000), and the regional center of the Thunder Bay District (TBD), which extends over an area of 103,720 square kilometers.…”

Disease Manifestations and Pathogenic Mechanisms of Group A Streptococcus

“…Several studies had noted a reduction in GAS disease burden in industrialized countries in the mid-20th century (11)(12)(13)(14). However, in the last 50 years, there have been widespread reports of significant outbreaks of ARF (15,16), APSGN (17,18), GAS invasive disease (14,(19)(20)(21), puerperal sepsis (22)(23)(24), and scarlet fever (25,26).…”

Description of the Pathogenic Features of <i>Streptococcus pyogenes</i> Isolates from Invasive and Non-Invasive Diseases in Aichi, Japan

“…Taken together, 1 hypervirulent emm12 strain in 2011 (strain D), 2 hypervirulent-like strains harboring emm3 in 2006 (Strain E) and emm12 340 strain in 2007 (Strain F) that lacked the sda1 or speA genes were identified among the non-invasive S. pyogenes isolates ( Table 2). To date, emm49 and emm59 have been reported to be the causative agents of epidemics of extremely invasive diseases in Japan and Canada, respectively (6,15). During the period of increased STSS prevalence in Japan, the predominant emm genotypes were emm89, emm12, emm28, emm3, and emm90, in addition to emm1 (6).…”