Role of rapid tests in diagnosis of bloodstream infections and their effect on promoting antibiotic stewardship among febrile neutropenic patients in Alexandria

Abstract

Abstract Background Bloodstream infections (BSIs) in neutropenic patients significantly contribute to morbidity and mortality. The rapid identification and determination of antimicrobial susceptibility of pathogens causing BSIs can help in early initiation of targeted antimicrobial therapy and allow de-escalation of unnecessary empirical antimicrobials. Aim This study evaluated the rapidity and accuracy of gram-stained smear from blood culture bottles and direct VITEK 2 to identify and determine antimicrobial susceptibility of pathogens causing BSIs and assessed the effect of these tests on modification of empiric therapy. Patients and methods Blood cultures were collected from 100 febrile neutropenic patients from the Hematology Unit in Alexandria Main University Hospital. Gram-stained smears were prepared from blood culture bottles; blood from bottles with suggestive smears was directly inoculated into the VITEK 2 system, and results were compared with conventional methods. Results were instantly reported to clinicians. Empirical antimicrobials and their modification were recorded. Results BSI was detected in 30% of patients. Gram-negative bacteremia was predominant (24/30). Gram-stained smears showed complete accordance with conventional methods in 99 samples. VITEK 2 correctly identified all tested microorganisms, and the overall agreement in susceptibility testing was 100 and 95.2% for gram-positive and gram-negative bacteria, respectively. The effect of these rapid tests on empiric antimicrobial therapy was evident in 12 of 30 patients with documented BSIs (40%). Conclusion Gram-stained smear and direct VITEK 2 testing when integrated with instant reporting is a valid approach to guide targeted therapy in neutropenic patients in the context of extremely resistant pathogens.