Group G streptococcal bacteraemia: an opportunistic infection associated with immune senescence.

The number of cases of group G streptococcal bacteraemia reported worldwide is increasing. Twenty-six cases of group G streptococcal bacteraemia were identified during a 70-month period at a single university teaching hospital in Sheffield, UK. These cases represented 20% of all bacteraemias due to beta-hemolytic Streptococci, a higher proportion than previously reported. The median age of these cases was 72 y and although medical comorbidities were common only cutaneous ulceration was clearly linked to the presenting syndromes. The skin was the source of infection in 16 cases (62%) and the most frequent clinical presentations were cellulitis in 13 cases (50%) and endovascular infection in 5 (19%). Eight (31%) of the cases died during the period of follow-up but only 2 deaths were related to the streptococcal infection. Immunosenescence represents the major risk factor for group G streptococcal infection in this population and comorbidities, including carcinoma, may be markers of the senescent immune system rather than direct contributing factors to group G streptococcal bacteraemia.