Changing incidence of detected streptococcal bacteraemia in North Yorkshire, England.

Objective: Streptococcal bacteraemia remains a major and challenging clinical problem throughout the world. The epidemiology of these infections appears to be changing. In the present study we analysed the data collected over a period of 20 yr (1978-1999) to throw light on this.

Methods: Laboratory records of all patients yielding clinically significant, non-pneumococcal, nonenterococcal streptococcal bacteraemia were reviewed for the decades 1978-1988 and 1990-1999 in the two districts (combined population 260,000).

Results: From a total of 3134 patients with detected bacteraemia 338 (10.8%) yielded streptococci. The organisms comprised: in the beta-haemolytic group (n=169), GAS (32%), GBS (34%), GCS (5%), GGS (28%), GRS (1%); in the non-haemolytic/Streptococcus milleri group (n=160): S. milleri (21%), S. bovis (10%), S. sanguis (30%), S.mitis (10%), S. oralis (8%) and other 'viridans' streptococci (20%); nine isolates were of anaerobic streptococci. There was a steady increase in the number of blood cultures submitted for investigation during the period and streptococcal isolations of all species rose in proportion (approximately x 2.5) in the second decade compared with the first. Complementary data on the occurrence of necrotising fasciitis and toxic shock syndrome in these districts suggested a real increase in the occurrence of serious forms of GAS infection.

Conclusions: An increase in the level of detected streptococcal bacteraemia was seen in this part of England over 20 yr, involving a wide variety of different streptococcal species. This represented both improved ascertainment of infection and an increase in the burden of disease in the population.