Beta-haemolytic group A, C and G streptococcal infections in Western Norway: a 15-year retrospective survey

Abstract

Pyogenic streptococci cause significant morbidity and mortality, and the incidence of invasive group C and G streptococcal disease appears to be increasing. In this retrospective study we describe the epidemiological characteristics of invasive group A, C and G, along with non-invasive group C and G streptococcal infections in Western Norway from 1999 to 2013. A total of 512 invasive streptococcal infections were identified, of these 297 (58%) were group A (GAS), 24 (5%) group C (GCS) and 188 (37%) group G streptococci (GGS). In the non-invasive group, 4935 GCS and GGS-infections were identified. GCS and GGS were treated as one group (GCGS) for statistical purposes. All microbial categories displayed increasing incidence with age, seasonal variation and a male predominance. The incidence of invasive GCGS infections increased significantly from 1.4/100,000 inhabitants in 1999 to 6.3/100,000 in 2013 (p <0.001). Conversely, the annual rates of invasive GAS infection exhibited marked fluctuations, ranging from 2.7/100,000 (2000) to 8.3/100,000 (1999), but no significant temporal trends were observed. The incidence of non-invasive GCGS infections decreased significantly during the study period (p <0.001). The most frequently encountered emm-types among the 209 iGAS-isolates analysed were emm1 (24%), emm3 (14%) and emm28 (14%); whereas stG643 (19%), stG485 (15%) and stG6 (13%) were most prevalent among the 122 iGCGS-isolates available for typing. The increasing burden of invasive β-haemolytic streptococcal disease in our community calls for sustained attentiveness to the clinical and molecular aspects of GAS, GCS and GGS infections.

Pathogenicity of Virulent Species of Group C Streptococci in Human

“…According to Danish data (1999–2002), GCS infections take the last place among streptococcal infections, but they constitute as many as 6% of all streptococcal infections [3]. This has also been confirmed by the Norwegian observations of 1999–2013, where out of 512 invasive infections GCS was the cause of 24 cases (4,7%) [12]. In both reports, the risk of infection increases with the patient's age [3, 12].…”

“…The virulence factor in some species of GCS most frequently mentioned is the M protein, the protein that also belongs to group A streptococci [2, 5, 7, 10, 12, 14, 21, 22]. This antiphagocytic, fibrillar, and surface-exposed M protein [14, 15] is encoded by the emm gene [12].…”

“…This antiphagocytic, fibrillar, and surface-exposed M protein [14, 15] is encoded by the emm gene [12]. Bisno's tests have shown that M protein can mainly be found in S. dysgalactiae subs.…”

“…The streptococcus of group C, which most often causes infection in humans, is Streptococcus dysgalactiae subs. equisimilis (SDSE) [10, 12]; it may cause skin infections (cellulitis) and recurrent blood infections [13]. According to Clarke the GCS species, not mentioned before, most often isolated from the human throat is S. milleri [8], also known as S. anginosus group [11].…”

Characteristics of Streptococcus Strains Isolated From Clinical Specimens Other Than Throat Culture and Characteristics of Streptococcal Infections

“…Yaşamı tehdit eden invaziv Streptococcus spp. enfeksiyonlarının dünya genelinde artış göstermesi erken tanı ve tedavinin önemini artırmıştır (2).…”