A comparison of lysis centrifugation, pour plate, and conventional blood culture methods in the diagnosis of septicaemic melioidosis

Abstract

Aims - To determine whether quantitative blood culture methods could improve the diagnosis of septicaemic melioidosis. Methods - A comparison of conventional broth based blood cultures, a pour plate method, and a commercial lysis centrifugation (Isolator 10(TM) blood culture system was conducted in 71 Thai patients with severe melioidosis. The time to identification of B pseudomallei was recorded for each method. Results - 42 patients (59%) were septicaemic. Compared with conventional blood culture, the Isolator and pour plate methods had sensitivities of 81% and 61%, respectively. The median times to a positive culture were: Isolator 39.3 hours, pour plates 45.5 hours, broth culture 61.8 hours (p < 0.001 Isolator υ broth). There was a significant inverse correlation between Isolator tube or pour plate quantitative counts and time to detection (r = -0.44 and -0.57, respectively). Mortality was higher in patients who were septicaemic. Conclusions - Routine use of one of these quantitative methods, in addition to conventional broth culture, may lead to earlier diagnosis of septicaemic melioidosis.