Combination of conventional blood cultures and the SeptiFast molecular test in patients with suspected sepsis for the identification of bloodstream pathogens

We evaluated performances of the molecular test SeptiFast (SF) for the detection of agents of bloodstream infection (BSI) in patients with suspected sepsis, the majority of them under antibiotic treatment and at high prevalence of HIV-1 infection (10.5%). Matched SF and blood culture (BC) samples (n=1186) from 1024 patients were studied. Two hundred fifty-one episodes of BSI out of 1144 were identified with the combined methods (22%). SF identified more episodes of BSI than BC: 206 versus 176 (χ2=7.008, P=0.0081) and a significantly higher number of Gram-negative bacteria than BC (77 versus 53, χ2=9.12; P=0.0025), as well as of polymicrobial infections (χ2=4.50, P=0.0339). In conclusion, SF combined with BC improved the diagnosis of sepsis, especially in immunocompromised patients.