Clinical and Epidemiological Aspects of Invasive Streptococcus pyogenes Infections in Denmark during 2003 and 2004

Abstract

Active surveillance of invasive group A streptococcal (GAS) infections was conducted in Denmark during2003 and 2004 as a part of the Strep-EURO initiative. The main objective was to improve understanding of the epidemiology of invasive GAS disease in Denmark. During the 2 years, 278 cases were reported, corresponding to a mean annual incidence of 2.6 cases per 100,000 inhabitants. The vast majority of isolates, 253 (91%), were from blood, with the remaining 25 (9%) being from cerebrospinal fluid, joints, or other normally sterile sites. The mean case fatality rate (CFR) was 20%, with the rate being higher in patients more than 70 years of age (36.5%). For streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis the CFRs were 53% and 25%, respectively. Out of 16 T types recorded, three predominated: T28 (23%), T1 (22%), and the cluster T3/13/B3264 (14%). Among 29 different emm types, emm28 and emm1 accounted for 51% of strains, followed by emm3 (11%), emm89 (7%), and emm12 (5.5%). Low resistance rates were detected for macrolide-lincosamide-streptogramin B (MLS B ) antibiotics (3%) and tetracycline (8%); two isolates exhibited coresistance to tetracycline and macrolides. Of nine pyrogenic exotoxin (superantigen) genes examined, speA and speC were identified in 58% and 40% of the strains, respectively; either of the genes was present in all strains causing STSS. Most strains harbored speG (99%). ssa was present in 14% of the isolates only. In Denmark, as in comparable countries, GAS invasive disease shows a sustained, high endemicity, with involvement of both established and emerging streptococcal emm and T types.

The M protein of group A Streptococcus is a key virulence factor and a clinically relevant strain identification marker

“…46,47 Studies suggest the M type distributions of many resistance traits are not well conserved over time and space. 22,34,36,[46][47][48] However, a recent US study showed that even these highly variable traits segregate significantly with M type over shorter periods of time. 44 Macrolide resistance offers an excellent example of a phenotype that is more highly correlated with M type and for which M typing offers a significant degree of predictive power.…”

“…Moreover, the types that are most dominant in invasive categories, and hence those responsible for the observed decrease in diversity, are almost always the same-most notably M1 and M3. 8,12,18,[32][33][34][35][36] Similar dynamics, including decreased diversity and the dominance of specific types, are apparent in studies of more specific clinical phenomena such as fatality, associated with M1, M3 and M12, 32 puerperal sepsis, associated with M28, 34,36,37 STSS, associated with M1 and M3, 12,35,38 epidemic ARF, associated with M5 and M18, 39 and geographically widespread epidemic behavior, most commonly associated with M1. 2,12 Despite genetic changes in these serotypes over time, including alterations of virulence and antibiotic resistance factors, these associations generally remain stable.…”

“…A study in Denmark comparing invasive isolates to uncomplicated pharyngitis strains showed that M1, M3 and M28 were dominant among invasive isolates. 34 Among these, M28 was specifically associated with puerperal sepsis, which the authors attributed to a unique collection of virulence factors apparently acquired from group B streptococci. 34 M28 has also been associated with puerperal sepsis in Norway.…”

“…34 Among these, M28 was specifically associated with puerperal sepsis, which the authors attributed to a unique collection of virulence factors apparently acquired from group B streptococci. 34 M28 has also been associated with puerperal sepsis in Norway. 36 A study in France found M28 in similar association with puerperal sepsis as well as other types of invasive infection, including necrotizing fasciitis, genital peritonitis, bacteremia, endocarditis and meningitis.…”

Severe monobacterial necrotizing soft tissue infection by group A Streptococcus: A surgical emergency

“…The recommended medical treatment for severe GAS disease includes a combination of a 毬 -lactam and clindamycin since no resistance has yet been reported against these drugs [13] , although local conditions and tissue ischemia, prevent adequate delivery of antibiotics in the area, and prevent bacterial destruction via aerobic mechanisms [9] , thus surgical debridement is imperative [14] . Both of our patients received early in their course an appropriate combination of antibiotics which nevertheless, did not delay or confine the extent of the infection.…”