A-309 Rapid Detection of Bloodstream Infections With the Bio Fire Blood Culture Identification 2 Panel Compared to Standard MALDI-TOF Identification

Abstract Background Effective antibiotic treatment for bloodstream infections relies, in part, on quickly identifying the specific pathogen and its susceptibility to therapy. The standard method—blood culture identification and antimicrobial susceptibility testing (AST)—can take several days, during which patients are often treated with empiric broad-spectrum antibiotics; however, this prolonged use can lead to the development of antibiotic resistance. A faster method for identifying pathogens and their resistance markers in blood cultures would allow clinicians to utilize the most appropriate targeted therapies and improve antimicrobial stewardship. This study compares a molecular panel for blood culture pathogen identification and antibiotic susceptibility with identification through mass spectrometry and standard AST. Methods Thirty-two positive blood culture samples routinely submitted to Quest Diagnostics were anonymized and nine additional spiked blood culture bottles were tested to identify the pathogens and check their antibiotic resistance. Pathogen identification was carried out by MALDI-TOF mass spectrometry and antibiotic susceptibility was assessed using the VITEK 2 system (MALDI-TOF/VITEK 2). For a comparison of concordance rates and assay time, results from molecular panel testing for pathogen identification and antibiotic susceptibility were obtained from BIOFIRE Blood Culture Identification 2 (BCID2). Results The MALDI-TOF/VITEK 2 and BCID2 methods identified the pathogen in positive blood cultures with a 97.6% concordance rate. Results from MALDI-TOF/VITEK 2 were obtained in 24 hours vs 1 hour by BCID2. According to MALDI-TOF/VITEK 2, one sample was positive for Streptococcus pyogenes and Streptococcus epidermidis but could only be identified as Streptococcus sp and S epidermidis by BCID2. BCID2 only identifies specific drug-resistance mechanisms in its panel while standard methods can detect resistance regardless of genetic factors. However, all resistance mechanisms detected by BCID2 matched the AST results observed through culture. Conclusion BCID2 showed similar performance to mass spectrometry and standard culture AST (MALDI-TOF/VITEK 2) but provided faster results. Quicker identification of positive blood cultures can enhance antimicrobial stewardship and improve patient outcomes.