Impact of Accelerated Antimicrobial Testing on Clinical Outcomes in Critically Ill Septicaemia Patients: A Prospective Observational Study form a Tertiary Care Centre in Andhra Pradesh, India

Abstract

Introduction: Bloodstream infection is a major cause of mortality and morbidity worldwide. Timely reporting of blood culture results is of utmost importance for better patient outcomes. The recently introduced Rapid Antimicrobial Susceptibility Testing (RAST) method is poised to profoundly influence clinical outcomes. Aim: To compare the results of RAST with Standard Antimicrobial Susceptibility Testing (SAST) and evaluate the impact of RAST reporting on the clinical management of septicaemia patients. Materials and Methods: This prospective, observational study was conducted in the Department of Microbiology, Government Medical College, Kurnool, Andhra Pradesh, India from May 2021 to September 2022. All positive blood culture bottles with only a single morphotype in gram staining were further processed using the RAST method, followed by conventional identification and SAST. Categorical agreement and disagreement between the RAST and SAST results were compared, along with the difference in the time at which results were available. Results: Out of a total of 1,146 blood cultures received, 228 were flagged as positive. A total of 514 isolate and antimicrobial agent combinations were evaluated, of which 496 (96.5%) showed categorical agreement. Only 18 (3.5%) showed categorical disagreement, with the majority being Major Errors (ME) (1.56%), followed by Very Major Errors (VME) (0.97%) and minor Errors (mE) (0.97%). Conclusion: RAST results demonstrated strong concurrence with SAST results. RAST is affordable, fast, and flexible and can potentially lead to a considerably shortened time for AST results to reach the bedside of the patient. This enables rapid modifications and adjustments in antibiotic therapy, including both escalation and de-escalation.