Rapid MALDI-TOF and membrane-based AST shorten blood culture turnaround time for Gram-negative pathogens
The study reports a method comparison evaluating rapid pathogen identification and antimicrobial susceptibility testing directly from positive blood cultures using separation gel tubes, MALDI-TOF mass spectrometry, and two rapid AST workflows. Investigators analysed 210 specimens and found identification concordance rates of 74.6% for Gram-negative bacteria, 37.2% for Gram-positive bacteria, and 14.3% for fungi. Both rapid AST approaches demonstrated excellent category agreement exceeding 96% for Gram-negative and Gram-positive cocci, with essential agreement above 97% and an overall category agreement of 94.7% across 98 isolates. The authors conclude that while the rapid identification workflow is most reliable for Gram-negative isolates, the combined AST methods can substantially reduce turnaround times and support earlier targeted therapy for bloodstream infections.
The original study
Rapid identification and antimicrobial susceptibility testing of pathogenic microorganisms from positive blood cultures.
- Authors
- Xu W, Liu X, Xu N, Li X, Liu F, Li Q, et al.
- Journal
- PloS one
- Type
- Journal Article
- PMID
- 42776995
Original abstract
PURPOSE: Bloodstream infections (BSIs) are severe illnesses associated with high mortality. Delays in obtaining microbial culture results often hinder timely targeted antimicrobial therapy. Our study aimed to evaluate the feasibility of rapid pathogen identification (ID) and antimicrobial susceptibility testing (AST) in BSIs. METHODS: Positive blood culture (BC) broth was transferred into separation gel vacuum blood collection tubes for preprocessing, followed by pathogen identification via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Identification concordance rates (ICRs) were calculated against the conventional reference method. Bacterial membrane rapid AST (BMR-AST) and positive blood culture medium rapid AST (PBCMR-AST) were performed using cultured bacterial membrane and raw positive BC medium, respectively, with results compared to conventional method. RESULTS: A total of 210 specimens were analysed for rapid ID. ICRs were 74.6% (88/118) for Gram-negative bacteria (GNB), 37.2% (29/78) for Gram-positive bacteria (GPB), and 14.3% (2/14) for fungi. BMR-AST yielded category agreement (CA) >96% for 58 GNB (96.8%, 1125/1162) and 24 Gram-positive cocci (GPC, 97.7%, 334/342), with essential agreement (EA) above 97% for both groups. PBCMR-AST achieved 94.1% CA (270/287) among 65 Enterobacterales; overall CA reached 94.7% (557/588) across 70 GNB and 28 GPC for additional antimicrobials. CONCLUSION: This rapid ID workflow performed well for GNB but suboptimally for GPB and fungi. Both rapid ASTs showed excellent concordance with the standard method for both GNB and GPC. These approaches can substantially shorten the turnaround time of positive BCs and hold promising clinical value for early BSI management.