Performance evaluation of the Specific Reveal system for rapid antibiotic susceptibility testing from positive blood cultures containing Gram-negative pathogens

Rapid antimicrobial drug administration is crucial for the efficient treatment of sepsis or septic shock, but empirical therapy is limited by the increasing prevalence of multidrug-resistant bacteria. Thus, rapid and reliable antimicrobial susceptibility testing (AST) is needed to start appropriate antimicrobial drug administration as quickly as possible. In the present study, we evaluated the performance of the Reveal rapid AST system. From February to April 2021, 102 positive blood culture bottles (BCBs) from hospitalized patients with bacteremia caused by Gram-negative bacteria were included in the study. All isolates were tested by the Reveal system directly from the positive BCBs in comparison to the DxM MicroScan WalkAway. Essential agreement (EA) and category agreement (CA) were high with 98.5% and 97.1%, respectively. We also determined the susceptibility of 10 highly resistant CDC & FDA AR strains in duplicate. Here, EA was 99.6% and CA 97.9%. The average time to result by Reveal was 5.4 h ± 1.2 h compared to an average of 16 h by DxM MicroScan WalkAway for clinical strains and 3.8 h ± 1.2 h for more resistant CDC & FDA AR strains. Susceptibility determination with the Reveal rapid AST system directly from positive BCBs is for the frequently represented bug-drug combinations a reliable and accurate approach, meeting the European ISO guideline for the performance of AST systems. Moreover, AST directly from blood cultures performed with the Reveal system saves time when compared to the conventional AST, as no subculturing is needed and time to result is very short.