Thrombocytopenia in bacteraemia and association with bacterial species

Abstract

AbstractThrombocytopenia is common in patients with invasive bacterial infections. Bacteria can activate platelets, but it is unclear if this affects platelet count. The aim of this study was to examine whether bacteraemia withStaphylococcus aureus, which readily activate human platelets, was more likely to be complicated by thrombocytopenia than bacteraemia withEscherichia coliorStreptococcus pneumoniaewith different abilities to activate platelets.We compared information from 600 adult patients with community-acquired bacteraemia withS. aureus(n= 140),E. coli(n= 420) andS. pneumoniae(n= 40) in Southern Sweden, 2012, linking information on positive blood cultures from microbiological databases and medical charts. The proportion of patients with thrombocytopenia (platelet count <150 × 109/ml) was calculated. Logistic regression was used to estimate the odds ratios (OR) for thrombocytopenia according to bacterial species adjusted for confounders.The proportion of thrombocytopenia was 29% inS. aureus, 28% inE. coliand 20% inS. pneumoniabacteraemia (P= 0.50), corresponding to an OR of 1.2 (95% confidence interval 0.7–1.9) for thrombocytopenia forS. aureusas compared withE. coliorS. pneumoniae, adjusted for confounders.This study indicates that platelet activation by bacteria is not a major causative mechanism in sepsis-associated thrombocytopenia.