Epidemiology of Invasive Group A Streptococcal Disease in Alaska, 2001 to 2013

Abstract

The Arctic Investigations Program (AIP) began surveillance for invasive group A streptococcal (GAS) infections in Alaska in 2000 as part of the invasive bacterial diseases population-based laboratory surveillance program. Between 2001 and 2013, there were 516 cases of GAS infection reported, for an overall annual incidence of 5.8 cases per 100,000 persons with 56 deaths (case fatality rate, 10.7%). Of the 516 confirmed cases of invasive GAS infection, 422 (82%) had isolates available for laboratory analysis. All isolates were susceptible to penicillin, cefotaxime, and levofloxacin. Resistance to tetracycline, erythromycin, and clindamycin was seen in 11% (n ‫؍‬ 8), 5.8% (n ‫؍‬ 20), and 1.2% (n ‫؍‬ 4) of the isolates, respectively. A total of 51 emm types were identified, of which emm1 (11.1%) was the most prevalent, followed by emm82 (8.8%), emm49 (7.8%), emm12 and emm3 (6.6% each), emm89 (6.2%), emm108 (5.5%), emm28 (4.7%), emm92 (4%), and emm41 (3.8%). The five most common emm types accounted for 41% of isolates. The emm types in the proposed 26-valent and 30-valent vaccines accounted for 56% and 78% of all cases, respectively. GAS remains an important cause of invasive bacterial disease in Alaska. Continued surveillance of GAS infections will help improve understanding of the epidemiology of invasive disease, with an impact on disease control, notification of outbreaks, and vaccine development.

Distribution of virulence genes and the molecular epidemiology of Streptococcus pyogenes clinical isolates by emm and multilocus sequence typing methods

“…The emm1/ST28 isolates that exhibited virulotype A and L in this study could pose a risk of clonal transmission in both hospitals. Hypervirulent characteristic of emm1/ST28 strain is typically associated with high fatality rates among invasive streptococcal cases in some countries [58,59]. The different emm/ST types that exhibited virulotype A in this study could be explained by the restricted or lack of transfer of phage-encoded superantigen genes within this clone.…”

Prevalent emm Types among Invasive GAS in Europe and North America since Year 2000

“…In Alaska, the Arctic Investigations Program set up a population-based laboratory surveillance program on iGAS infections during the period 2001–2013 ( 61 ). Overall, 516 cases of iGAS infections were reported, and 422 isolates were available for microbiological analysis and typing.…”

Éclosion communautaire d'une infection invasive à streptocoque du groupe A en Ontario, Canada

“…L'encadré 1 résume la définition de cas du ministère de la Santé et des Soins de longue durée de l'Ontario pour les cas d'iSGA confirmés en laboratoire (3). Bien que peu fréquente lorsqu'on la compare à l'infection non invasive à SGA, l'iSGA est associée à un taux de morbidité et de mortalité élevé, car la bactérie cause de graves séquelles comme la pneumonie, la méningite, la fasciite nécrosante, la sepsie et le syndrome de choc toxique streptococcique (4,5). Pour les isolats de SGA, la protéine M (encodée par le gène emm) est un facteur épidémiologique de virulence important qui affecte la capacité du pathogène à éluder la réponse immunitaire humaine à l'infection (6).…”