Distribution and clinical determinants of time-to-positivity of blood cultures in patients with neutropenia

作者：Lambregts Merel M. C.^*; Warreman Eva B.; Bernards Alexandra T.; Veelken Hendrik; Borne Peter A. von Dem; Dekkers Olaf M.; Visser Leo G.; de Boer Mark G.

来源：European Journal of Haematology, 2018, 100(2): 206-214.

DOI：10.1111/ejh.13001

• blood culture
• empiric treatment
• neutropenia
• time-to-positivity

Objectives: Blood cultures (BCs) are essential in the evaluation of neutropenic fever. Modern BC systems have significantly reduced the time-to-positivity (TTP) of BC. This study explores the probability of bacteraemia when BCs have remained negative for different periods of time.
Methods: All adult patients with neutropenia and bacteraemia were included (January 2012-February 2016). Predictive clinical factors for short (<= 16 hours) and long (> 24 hours) TTP were determined. The residual probability of bacteraemia was estimated for the scenario of negative BC 24 hours after collection.
Results: The cohort consisted of 154 patients, accounting for 190 episodes of bacteraemia. Median age of 61 years, 60.5% were male. In 123 (64.7%) episodes, BC yielded a single Gram-positive micro-organism and in 49 (25.8%) a Gram-negative micro-organism (median TTP 16.7, 14.5 hours respectively, P <.01). TTP was <= 24 hours in 91.6% of episodes. Central line-associated bacteraemia was associated with long TTP. The probability of bacteraemia if BC had remained negative for 24 hours was 1%-3%.
Conclusions: The expected TTP offers guidance in the management of patients with neutropenia and suspected bacteraemia. The knowledge of negative BC can support a change in working diagnosis, and impact clinical decisions as soon as 24 hours after BC collection.

• 出版日期2018-2