Wednesday, February 19, 2014

Culture positive versus culture negative sepsis

This study looked at 1001 septic patients and compared attributes and outcomes between the culture positive and culture negative groups:

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 less than 0.001). After adjusting for covariates, culture positivity was not independently associated with mortality on multivariable analysis.

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