Epidemiology, Clinical Characteristics, and Outcomes of Culture-negative Sepsis

Abstract

Aim: Culture-negative sepsis (CNS) is a common but understudied entity. The objective of this study was to compare the incidence, characteristics, and outcomes of CNS with culture-positive sepsis (CPS). Methods: This was a prospective observational study of patients admitted to the medical intensive care unit (ICU) of a tertiary hospital from January to December 2015 with clinical suspicion of severe sepsis as defined by Consensus Conference Criteria 2001. Results: Patients with severe sepsis ( n = 122) were studied of whom 66 (54%) were CPS and 56 (46%) were CNS. Patients with CNS had fewer comorbidities (0.7 ± 0.70 vs. 2 ± 0.8, P < 0.01). At presentation, CNS patients had less tachycardia (heart rate 92.5 ± 10.5 vs. 105.9 ± 13.2, P < 0.01), lower white blood cell counts (11859 ± 4791 vs. 14224 ± 3898, P = 0.003), lower need for vasopressors (38% vs. 68%, P < 0.01), and mechanical ventilation (23% vs. 53%, P < 0.01) compared to patients with CPS. The number of antibiotics on admission was similar between the groups (1.5 ± 0.6 vs. 1.6 ± 0.6, P = 0.36) but the duration of antibiotics was less in CNS (7.6 ± 1.7 days vs. 10.4 ± 2.6 days, P < 0.01). CNS had lower duration of ICU stay (6 ± 2.1 days vs. 7.8 ± 3.7 days, P < 0.01) and lower ICU mortality (7.1% vs. 22.7%, P = 0.02). Conclusion: CNS is very common in ICU. CNS patients compared to CPS tend to be less sick at presentation utilizing less resources but were initiated on a similar number of antibiotics on admission although for a shorter duration. Patients with CNS had a lower mortality in comparison to those with CPS.