Invasive meningococcal disease associated with a very high case fatality rate in the North-West of Poland.

The aim of the study was to investigate invasive meningococcal disease in the North-West of Poland, associated with a case fatality rate of 42.9%, where among the first 11 cases, eight had fatal outcome. All fatal cases were diagnosed as fulminant meningococcal severe sepsis with Waterhouse-Friderichsen syndrome and disseminated intravascular coagulation. Serotyping and pulsed-field gel electrophoresis analysis revealed that the high case fatality rate was not associated with the dissemination of one epidemic clone. However, six cases, all with good outcomes, were caused by C:2b:(P1.2,P1.5) isolates of the same pulsed-field gel electrophoresis type belonging to ST8 complex/Cluster A4.