How could rapid bacterial identification improve the management of septic patients?

Severe sepsis and septic shock have been the major motivation behind microbiologists’ attempts to identify bacteria present in the blood quickly. Rapid identification (ID) tools exist when blood culture (BC) bottles are positive (e.g., MALDI, FISH, PCR, microarrays and so on) [1–5], but it has become obvious that there is clinical need to identify bacteria in the blood far more rapidly than the time required to grow a bacterial culture! Several companies have developed multiplexed PCR assays (e.g., Septifast, Roche) [6] or more recently a PCR–electro spray ionization mass spectrometry platform (PlexID, Abbott Molecular) [7,8] to provide a very rapid ID of the pathogen(s) directly from whole blood. . These attempts currently remain limited by difficulties with detecting bacterial DNA from whole blood due to the very low concentration of bacteria in the blood of adults, even during severe sepsis (1–30 CFU/ml) [9,10]. Aside from such technical limitations and despite the fact that every hour without adequate treatment in septic shock is clearly associated with a 7.6% decrease in survival [11,12], doubts remain about the real impact of a rapid ID in such situations: