Normal leukocyte counts in Staphylococcus aureus septicaemia.

Staphylococcus aureus septicaemia is still a serious disease with a high mortality. The absence of leukocytosis in serious bacterial infections is generally considered as an unfavourable prognostic sign. The leukocyte pattern in 75 patients with S. aureus septicaemia was reviewed retrospectively. In the 66 patients where leukocyte determinations were done within 2 days of positive blood culture, 21 presented without leukocytosis which contrasts to only 1/35 patients with Escherichia coli septicaemia studied as controls (p less than 0.001). During follow up of S. aureus septicaemia only 5 of the patients developed leukocytosis greater than 10 x 10(9)/l and 2 leukopenia. There was no significant difference in mortality in patients without initial leukocytosis (14%) compared to patients with initial leukocytosis (24%). Except for septic arthritis, which was associated significantly more often with leukocytosis, complications were found with about the same frequency in both groups. Thus absence of leukocytosis seems not be an unfavourable prognostic sign in S. aureus septicaemia.