We describe associations between death from invasive pneumococcal diseases (IPD) and particular serogroups and Multi Locus Sequence Types (MLST) using data from Scotland. All IPD episodes where blood or cerebrospinal fluid (CSF) culture isolates were referred to the Scottish Haemophilus, Legionella, Meningococcal and Pneumococcal Reference Laboratory (SHLMPRL) from January 1992 to February 2007 were matched to death certification records by the General Register Office for Scotland. This represented 5,959 patients. The median number of IPD cases in Scotland each year was 292. Deaths, from any cause, within 30 days of pneumococcal culture from blood or CSF were considered to have IPD as a contributing factor. Eight hundred and thirty three patients died within 30 days of culture of Streptococcus pneumoniae from blood or CSF (13.95%; 95% Confidence Interval (13.10, 14.80)). The highest death rates were in patients over the age of 75. Serotyping data exists for all years but MLST data was only available from 2001. The risk ratio of dying from infection due to particular serogroups or sequence types compared to dying from IPD due to all other serogroups or sequence types was calculated. Fisher's Exact Test with Bonferonni adjustment for multiple testing was used. Age adjustment was accomplished using the Cochran-Mantel-Haenszel Test and 95% confidence intervals were reported. Serogroup 3, 11 and 16 have increased probability of causing fatal IPD in Scotland while Serogroup 1 IPD has a reduced probability of death. None of the 20 most common Sequence Types were significantly associated with death within 30 days of pneumococcal culture, after age adjustment. We conclude that there is a stronger association between a fatal outcome and pneumococcal capsular serogroup than there is between fatal outcome and MLST.
- invasive pneumococcal disease
- cerebrospinal fluid
- pneumococcal culture