Background Klebsiella pneumoniae infections, especially Carbapenem-resistant Klebsiella pneumoniae (CRKP), have become an “Urgent Threats” with high morbidity and mortality. Therefore, rapidly determining of the susceptibility and timely choosing an appropriate antibiotic were the important premises of the treatment of Klebsiella pneumoniae infections. The present study was first to explore the fitness of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) in quantitative rapid antimicrobial susceptibility testing (RAST) with optimal conditions. Methods Firstly, we optimized the methodology based on the formic acid extraction method. Taking broth micro-dilution method (BMD) as a reference method, we utilized 25-fold, 50-fold and 100-fold dilutions matching with appropriate incubation time to evaluate the consistency of minimum inhibition concentration (MIC) values derived from BMD and MALDI-TOF MS. Finally, the performances of optimal dilution and incubation time were verified through the reproducibility on different three days. Results Directly incubated in the EP tubes and skipped the washing step can not only simplify the procedure, but reduce the unnecessary loss of bacteria biomass to improve sensitivity. The optimal volumes of 70% formic acid/100% acetonitrile (FA/ACN) and supernatant on the target plate were 3 µL and 2 µL, respectively. Comparing the different combination, 25-fold dilution of the 0.5 McFarland suspension and 2hr incubation time resulted in best performance. The consistency between the MS-MIC and corresponding BMD-MIC values in CRKP and Carbapenem-susceptible Klebsiella pneumoniae (CSKP) strains accounted for 76.67% and 66.67%, respectively, which generated the substantial agreements between MS-MIC and BMD-MIC values for CRKP strains (Kappa=0.643) and the moderate agreements for CSKP strains (Kappa=0.476). Finally, the MALDI-TOF MS-based RAST showed a well repeatability. Conclusion Considerable potentials were demonstrated for universal and mechanism-indepent RAST by MALDI-TOF MS with optimal conditions, which strengthened its application in accelerating reporting time and clinical diagnosis.
Background: It can be a critical point for reducing pathogen identification time and accurate antibiotic treatment for patients with blood circulation infection since it causes high mortality. Objective: The objectives of this study were to evaluate the time differences between conventional identification and MALDI-TOF conventional identification and short-incubation MALDI-TOF identification for positive blood cultures, and to explore the impact of short-incubation matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) identification on empirical antibiotic therapy. Methods: Positive blood cultures were collected in our hospital from 2017 to 2019, clinical data were collected from the medical records, which were analyzed retrospectively to determine the empirical antibiotic therapy. Results: Compared with the conventional identification method, the short-incubation MALDI-TOF identification time to initial identification of Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, Enterococcus faecium, and E. faecalis decreased by 22.28 h, 22 h, 23.59 h, 23.63 h, 22.63 h, 23.92 h, and 21.59 h, respectively (P < 0.05). The time to final reporting was decreased by 48.85 h, 47.99 h, 55.40 h, 51.07 h, 49.60 h, 51.78h, and 51.73h, respectively (P < 0.05). However, the antimicrobial susceptibility test time of E. coli, A. baumannii, and S. aureus increased to 2.02 h, 2.19 h, and 3.86 h, respectively (P < 0.05). The coincidence rate of antimicrobial susceptibility was 98.48% between short-incubation MALDI-TOF identification and conventional identification method of all Gram-negative bacilli, and there were no extremely major errors or major errors. The coincidence rate of antimicrobial susceptibility of Gram-positive cocci was 99.53%, one strain of E. faecium and S. aureus had major errors. Patients received earlier correct empirical antibiotic 19.89 h earlier by short-incubation MALDI-TOF identification than the conventional identification method (P < 0.001). Conclusions: The short-incubation MALDI-TOF identification significantly shortens the pathogen identification time and the final report time, it is a reliable method for rapid identification of positive blood cultures; the results of antimicrobial susceptibility are highly consistent, which significantly lead to earlier appropriate empirical therapy of bacteremia.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.