Impact of rapid diagnosis of Staphylococcus aureus bacteremia from positive blood cultures on patient management.

We have performed a retrospective, before-after comparison of turnaround time and therapy adjustment parameters before and after the introduction of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) plus mecA polymerase chain reaction (PCR) for the identification of methicillin-resistant Staphylococcus aureus (MRSA) in positive blood cultures. There were 227 episodes of S. aureus bacteremia during the study periods. The pre-MALDI-TOF and post-MALDI-TOF groups included 133 and 94 patients, respectively. The two rapid methods performed sequentially decreased the turnaround time of MRSA identification by nearly 50% (2.06 ± 1.95 vs. 3.95 ± 1.70 days). There was no significant reduction in the length of hospitalization (28.27 ± 32.16 vs. 28.62 ± 28.75 days). In both groups, the adequacy of the empirical antibacterial therapy was similar (59.49% vs. 51.31%), but the optimization of the therapy was more frequent in the post-MALDI-TOF group. Routine implementation of these techniques provides results earlier than conventional methods and increases the proportion of episodes with adequate change of empirical to directed antimicrobial therapy.