Characteristics and outcomes of culture-negative versus culture-positive severe sepsis.
Crit Care. 2013 Sep 12;17(5):R202
Authors: Phua J, Ngerng WJ, See KC, Tay CK, Kiong T, Lim HF, Chew MY, Yip HS, Tan A, Khalizah HJ, Capistrano R, Lee KH, Mukhopadhyay A
Abstract
INTRODUCTION: Culture-negative sepsis is a common but relatively under-studied condition. The aim of this study was to compare the characteristics and outcomes of culture-negative versus culture-positive severe sepsis.
METHODS: This was a prospective observational cohort study of 1001 patients who were admitted to the medical intensive care unit (ICU) of a university hospital from 2004 to 2009 with severe sepsis. Patients with documented fungal, viral, and parasitic infections were excluded.
RESULTS: There were 415 culture-negative patients (41.5%) and 586 culture-positive patients (58.5%). Gram-positive bacteria were isolated in 257 patients, and gram-negative bacteria in 390 patients. Culture-negative patients were more often women and had fewer comorbidities, less tachycardia, higher blood pressure, lower procalcitonin levels, lower Acute Physiology and Chronic Health Evaluation II [median 25.0 (interquartile range 19.0-32.0) versus 27.0 (21.0-33.0), P = 0.001] and Sequential Organ Failure Assessment scores, less cardiovascular, central nervous system, and coagulation failures, and less need for vasoactive agents than culture-positive patients. The lungs were a more common site of infection, while urinary tract, soft tissue and skin infections, infective endocarditis and primary bacteremia were less common, in culture-negative than in culture-positive patients. Culture-negative patients had a shorter duration of hospital stay [12 days (7.0-21.0) versus 15.0 (7.0-27.0), P = 0.02] and lower ICU mortality than culture-positive patients. Hospital mortality was lower in the culture-negative group (35.9%) than in the culture-positive group (44.0%, P = 0.01), the culture-positive subgroup which received early appropriate antibiotics (41.9%, P = 0.11), and the culture-positive subgroup which did not (55.5%, P <0.001). After adjusting for covariates, culture positivity was not independently associated with mortality on multivariable analysis.
CONCLUSIONS: Significant differences between culture-negative and culture-positive sepsis are identified, with the former group having fewer comorbidities, milder severity of illness, shorter hospitalizations, and lower mortality.
PMID: 24028771 [PubMed - as supplied by publisher]