1217. Clinical and Microbiological Characteristics of Patients with Bacteremia and Normal Procalcitonin at Single Tertiary Care Medical Center

Abstract

BackgroundProcalcitonin (PCT) is a serum biomarker used to diagnose bacterial infections and guide antibiotic therapy. Many studies highlight its high sensitivity, specificity, and negative predictive value for bacteremia. PCT > 2ng/mL has been reported to be strongly indicative of systemic bacterial infection, with values of .5-2ng/mL suggesting localized infection and < .5ng/mL strongly suggesting absence of infection. However, emerging reports have raised concerns about PCT in bacteremia, demonstrating low sensitivity. Few studies have characterized patients with bacteremia and low PCT. We aimed to analyze the clinical and microbiological characteristics of patients with bacteremia and PCT < 2ng/mL.MethodsAdult patients admitted at Westchester Medical Center with bacteremia and associated PCT level within 24 hours (hrs) prior to 48 hrs post blood culture collection from 1/1/2014-9/30/2019 were included. Demographic, clinical, laboratory, and microbiological data were retrospectively collected and analyzed.ResultsThere were 414 total cases of bacteremia with an associated PCT level within 24 hrs prior to 48 hrs post blood culture collection. 209 of 414 (50.5%) patients had PCT < 2ng/mL. Of these, 86 were excluded (73 contaminants, defined as bacteremia not causing systemic inflammation and not treated, 10 fungal cultures, and 3 lacking data). Of the remaining 123 (37.5%) patients with PCT < 2ng/mL, 66 (53.7%) had PCT<. 5ng/mL. The leading infection source was endovascular/line-related at 31.7%, followed by intraabdominal/gastrointestinal and urinary. 30.9% of bloodstream organisms were gram negative. Among these 123 patients with PCT < 2ng/mL, in-hospital mortality with bacteremia clinically contributing to death was 13%.Characteristics of patients with bacteremia and procalcitonin < 2ng/mL ConclusionDespite literature supporting the use of PCT algorithms in initiation and de-escalation of antibiotics in patients with suspected bacterial infections, a substantial percentage of bacteremic patients can have low PCT but significant infection-related mortality. Therefore, PCT should not be the only factor utilized by clinicians in the management of such patients, including initiating or deescalating antibiotics. Further studies are needed to characterize patient characteristics as contributing factors for bacteremia with low PCT.Disclosures All Authors: No reported disclosures