[Does a rapid antibiotic susceptibility test optimize antibiotic therapy of patients with bacteremia ?]

BACKGROUND:We evaluated the contribution of a rapid antibiotic susceptibility test performed directly from a positive blood culture (PBC), the dRAST™, in the management of patients with bacteremia. METHODS:We retrospectively compared the time from sampling to availability of antibiotic susceptibility test (AST) results («time-to-result», TTR) between dRAST™ and classic AST (Vitek®2), in 150 patients with bacteremia. The antibiotic treatment of these 150 patients was classified into three categories (optimal, suboptimal, ineffective) according to the time of availability of AST results. RESULTS:Adaptation of antibiotic treatment to optimal therapy following AST results occurred in 46/100 (46 %) of Gram-negative PBC and in 4/50 (2 %) of Gram-positive HP. TTR was significantly lower with dRAST™ compared with classic AST (29:35 (± 08:48) hours versus 50:55 (± 12:45) hours, p < 0.001). CONCLUSION:For patients with bacteremia requiring adjustment of empirical antibiotic therapy based on AST, dRAST™ could allow a faster administration of optimal therapy.