icu = intensive care unit ; ifn = interferon ; il = interleukin ; lps = lipopolysaccharide ; pcr = polymerase chain reaction ; tlr = toll - like receptor ; tnf = tumour necrosis factor .
hg , te , and sf planned , drafted , read , and approved the final manuscript .
this article is part of a review series on infection , edited by steven opal .
 international guidelines concerning the management of patients with sepsis , septic shock and multiple organ failure make no reference to the nature of the infecting organism . indeed 
 , most clinical signs of sepsis are nonspecific . in contrast , in vitro data suggest that there are mechanistic differences between bacterial , viral and fungal sepsis , and imply that pathogenetic differences may exist between subclasses such as gram - negative and gram - positive bacteria . 
 these differences are reflected in different cytokine profiles and mortality rates associated with gram - positive and gram - negative sepsis in humans . 
 they also suggest that putative anti - mediator therapies may act differently according to the nature of an infecting organism . 
 data from some clinical trials conducted in severe sepsis support this hypothesis . 
 it is likely that potential new therapies targeting , for example , toll - like receptor pathways will require knowledge of the infecting organism . 
 the advent of new technologies that accelerate the identification of infectious agents and their antimicrobial sensitivities may allow better tailored anti - mediator therapies and administration of antibiotics with narrow spectra and known efficacy . 
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