[Etiology of postoperative bacteremias in an intensive care unit: an association with the level of procalcitonin].

The etiology of bacteremia determines the choice of adequate therapy for severe infections. The clinical manifestations of gram-negative and gram-positive bacterial infections are similar while biological markers may serve as a guide for the early diagnosis of the nature of a pathogen. The paper analyzes data on the rate and etiology of bacteremia in 1360 patients at the A. N. Bakulev Research Center of Cardiovascular Surgery over a period of 5 years (2002-2006). The purpose of the study was to assess an association between the level of procalcitonin (PCT) and the etiology of bacteremia. A hundred and fifty consecutive cases of documented bacteremia were analyzed in detailed in 113 cardiac surgical patients in the postoperative period, by comparing them with the level of on concurrent blood sampling for culture and PCT. In the gram-negative bacteremia group, plasma PCT levels were statistically significantly higher than in the gram-positive bacteremia group (5.40 and 0.86 ng/mg, respectively; p = 0.000000). On constructing a characteristic curve, the authors determined the PCT cut-off value of 5.2 ng/ml for the differential diagnosis of gram-negative and gram-positive bacteremia with the maximum (86%) specificity and more than 50% specificity. Thus, when patients with suspected infections have plasma PCT levels, the leading value of gram-negative microorganisms may be supposed just before obtaining blood culture results.