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

AbstractPyogenic 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