MALDI-TOF MS in Adult Inpatients with Bloodstream Infections: Pre- and Post-intervention Study

Abstract Background Correctly identifying anaerobic bloodstream infections (BSIs) is difficult. However, a new technique, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), enables more accurate identification and appropriate treatment. Anaerobic BSIs identified by MALDI-TOF MS were retrospectively analyzed to determine the clinical and microbiological features and patient outcomes based on the anaerobic genera or group. Methods Medical records of patients with anaerobic BSIs were used to conduct a single-center retrospective cohort study from January 2016 to December 2020 in Nagoya, Japan. Multivariate logistic regression analysis was performed to determine the independent risk factors for in-hospital mortality. Results Of the 215 patients with anaerobic BSIs, 31 had multiple anaerobic organisms in the blood culture, including 264 total episodes of anaerobic BSIs. Bacteroides spp. were isolated the most (n = 74), followed by gram-positive non-spore-forming bacilli (n = 57), Clostridium spp. (n = 52), gram-positive anaerobic cocci (GPAC) (n = 27), and gram-negative cocci (n = 7). The median patient age was 76 years; 56.7% were male. The most common focal infection site was intra-abdominal (36.7%). The in-hospital mortality caused by anaerobic BSIs was 21.3%, and was highest with Clostridium spp. (36.5%) and lowest with GPAC (3.7%). Age, solid tumors, and Clostridium spp. were independent risk factors for in-hospital mortality. Conclusions We identified current anaerobic BSI trends using MALDI-TOF MS and reported that mortality in patients with anaerobic BSIs patients was highest with Clostridium spp. infections.

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Impact of short-incubation MALDI-TOF MS on empiric antibiotic therapy in bloodstream infections caused by Pseudomonas aeruginosa, Enterococcus spp. and AmpC-producing Enterobacteriaceae

Diagnostic Microbiology and Infectious Disease ◽

10.1016/j.diagmicrobio.2018.11.009 ◽

2019 ◽

Vol 94 (1) ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Mika Halavaara ◽

Annika Nevalainen ◽

Timi Martelius ◽

Pentti Kuusela ◽

Veli-Jukka Anttila

Keyword(s):

Pseudomonas Aeruginosa ◽

Antibiotic Therapy ◽

Bloodstream Infections ◽

Empiric Antibiotic Therapy ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Enterococcus Spp ◽

Empiric Antibiotic ◽

Tof Ms

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55. Impact of Testing Methodology and Reporting on Time to Preferred Antibiotic Therapy in Extended Spectrum Beta-Lactamase producing Enterobacteriaceae (ESBL-E) Bloodstream Infections

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab466.257 ◽

2021 ◽

Vol 8 (Supplement_1) ◽

pp. S147-S147

Author(s):

Hanh Bui ◽

Frank Tverdek ◽

Stephanie Carnes ◽

Jeannie D Chan ◽

Andrew Bryan ◽

...

Keyword(s):

Blood Culture ◽

Medical Center ◽

Bloodstream Infections ◽

Blood Cultures ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Definitive Therapy ◽

Significant Difference ◽

Carbapenem Antibiotic ◽

Tof Ms

Abstract Background Harborview Medical Center (HMC) identifies organisms and an ESBL genotype (CTX-M) via Verigene® Gram-Negative Blood Culture Nucleic Acid Test (BC-GN). University of Washington-Montlake (UWML) uses matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for organism identification directly from positive blood cultures and ceftriaxone results by Kirby Bauer disk diffusion (KB) are reported 18 hours later. No ESBL comment is reported at UWML. We aimed to determine whether the methodology in identification and reporting of ESBL-E from blood cultures between two hospitals has an impact on time to preferred therapy with a carbapenem antibiotic. Methods Retrospective observational study conducted at UWML and HMC in Seattle, WA between 1/10/2015 and 9/15/2020. Adult patients were eligible if they had ≥1 positive blood culture with an Enterobacteriaceae isolate resistant to ceftriaxone and were on antibiotic treatment. The primary outcome was the difference in time to preferred definitive therapy with a carbapenem antibiotic in patients an ESBL-E bloodstream infection (BSI) identified by Verigene® vs. MALDI-TOF MS/KB. Results A total of 199 patients were screened; 67 were included for UWML and 68 at HMC. The average time to initiation of a carbapenem antibiotic was 42 ±26.5 hours at UWML and 28 ±19.7 hours at HMC. A t-test detected a difference in time to preferred therapy between a Verigene® vs. MALDI-TOF MS/KB tested ESBL-E BSI [95% confidence interval (CI), 5.3-22.9]. The hazard ratio to carbapenem initiation for HMC is 1.73643 [95% CI, 1.1405-2.644]. Conclusion A statistically significant difference in time to preferred definitive therapy among patients with an ESBL-E BSI processed by Verigene® was found compared to MALDI-TOF MS. The results suggest standardization in protocols between the UWML and HMC hospitals is warranted. Disclosures Andrew Bryan, MD, PhD, Shionogi Inc. (Grant/Research Support)

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Comparison of Accelerate PhenoTest™ BC Kit vs. MALDI-TOF MS/VITEK®2 System for the Rapid Identification and Antimicrobial Susceptibility Testing of Gram-negative Bacilli Causing Bloodstream Infections

10.21203/rs.2.18496/v1 ◽

2019 ◽

Author(s):

William Stokes ◽

Lorraine Campbell ◽

Johann Pitout ◽

John Conly ◽

Deirdre Church ◽

...

Keyword(s):

Antimicrobial Susceptibility ◽

Susceptibility Testing ◽

Bloodstream Infections ◽

Antimicrobial Susceptibility Testing ◽

Clinical Samples ◽

Gram Negative ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Conventional Methods ◽

Tof Ms

Abstract Introduction: Our laboratory uses MALDI-TOF MS (MALDI) and the VITEK®2 system (DV2) directly from positive blood cultures (BC) for organism identification (ID) and antimicrobial susceptibility testing (AST). Our objective was to compare direct MALDI/DV2 to a commercial BC ID/AST platform, the Accelerate Pheno™ system, in the ID/AST of clinical and seeded BC positive for Gram-negative bacilli (GNB). Methods: BC positive for GNB were collected over a three month period and tested using AXDX, direct MALDI/DV2, and compared to conventional methods. A subset of sterile BC were seeded with multi-drug resistant GNB. Discrepancies in very major errors (VME) and major errors (ME) were confirmed with broth microdilution. Results: A total of 29 clinical samples and 35 seeded samples were analyzed. Direct MALDI had a higher ID failure rate (31.0%) compared to AXDX (3.4%) [p<0.001]. Time to ID/AST was 1.5/6.9 hours, 5.8/16.5 hours and 21.6/33.0 hours for AXDX, direct MALDI/DV2 and conventional methods, respectively (p<0.001). For clinical samples, AXDX and DV2 had essential agreement (EA)/categorical agreement (CA) >96%. For seeded samples, AXDX had EA, CA, VME, ME and mE of 93.2%, 89.0%, 2.2%, 0%, and 9.2%, respectively. AXDX had a large number of non-reports (6.1%), stemming from meropenem testing. DV2 had EA, CA, VME, ME and mE of 97.5%, 94.7%, 1.3%, 0%, and 4.4%, respectively. Conclusions: AXDX had fewer ID failures and more rapid ID/AST results. Direct MALDI/DV2 and AXDX both had high agreement for clinical samples but direct MALDI/DV2 had higher agreement when challenged with MDR GNB.

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MALDI-TOF MS in post-transplant bloodstream infections: reliable identification of causative bacteria in the neutropenic phase

Bone Marrow Transplantation ◽

10.1038/bmt.2016.365 ◽

2017 ◽

Vol 52 (5) ◽

pp. 778-780 ◽

Cited By ~ 1

Author(s):

M Kanaya ◽

Y Hayashi ◽

D Hashimoto ◽

T Endo ◽

J Sugita ◽

...

Keyword(s):

Bloodstream Infections ◽

Reliable Identification ◽

Maldi Tof Ms ◽

Post Transplant ◽

Maldi Tof ◽

Tof Ms

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Performance of two MALDI-TOF MS systems for the identification of yeasts isolated from bloodstream infections and cerebrospinal fluids using a time-saving direct transfer protocol

Medical Microbiology and Immunology ◽

10.1007/s00430-013-0319-9 ◽

2013 ◽

Vol 203 (2) ◽

pp. 93-99 ◽

Cited By ~ 31

Author(s):

Axel Hamprecht ◽

Sara Christ ◽

Tanja Oestreicher ◽

Georg Plum ◽

Volkhard A. J. Kempf ◽

...

Keyword(s):

Bloodstream Infections ◽

Direct Transfer ◽

Time Saving ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Tof Ms ◽

Transfer Protocol

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Comparative Analysis of PCR–Electrospray Ionization/Mass Spectrometry (MS) and MALDI-TOF/MS for the Identification of Bacteria and Yeast from Positive Blood Culture Bottles

Clinical Chemistry ◽

10.1373/clinchem.2011.161968 ◽

2011 ◽

Vol 57 (7) ◽

pp. 1057-1067 ◽

Cited By ~ 81

Author(s):

Erin J Kaleta ◽

Andrew E Clark ◽

Abdessalam Cherkaoui ◽

Vicki H Wysocki ◽

Elizabeth L Ingram ◽

...

Keyword(s):

Blood Culture ◽

Diagnostic Accuracy ◽

Bloodstream Infections ◽

Rapid Identification ◽

Blood Cultures ◽

Reference Standard ◽

Maldi Tof Ms ◽

Esi Ms ◽

Maldi Tof ◽

Tof Ms

BACKGROUND Emerging technologies for rapid identification of microbes demonstrate a shift from traditional biochemical and molecular testing algorithms toward methods using mass spectrometry (MS) for the semiquantitative analysis of microbial proteins and genetic elements. This study was performed to assess the diagnostic accuracy of 2 such technologies, PCR–electrospray ionization (ESI)/MS and MALDI-TOF/MS, with respect to phenotypic and biochemical profiling as a reference standard method. A positive challenge set of blood culture bottles was used to compare PCR-ESI/MS and MALDI-TOF/MS performance on a matched set of samples. METHODS We performed characterization of bloodstream infections from blood cultures using the Ibis T5000 PCR-ESI/MS and the Bruker MALDI Biotyper 2.0 (MALDI-TOF/MS) platforms for microbial identification. Diagnostic accuracy was determined by independent comparison of each method to phenotypic and biochemical characterization with Vitek2 analysis as the reference standard identification. RESULTS The diagnostic accuracy, represented as positive agreement, at the genus level was 0.965 (0.930–0.984) for PCR-ESI/MS and 0.969 (0.935–0.987) for MALDI-TOF/MS, and at the species level was 0.952 (0.912–0.974) with PCR-ESI/MS and 0.943 (0.902–0.968) for MALDI-TOF/MS. No statistically significant difference was found between PCR-ESI/MS and MALDI-TOF/MS in the ability to rapidly identify microorganisms isolated from blood culture. CONCLUSIONS Our results demonstrate that PCR-ESI/MS and MALDI-TOF/MS are equivalent in their ability to characterize bloodstream infections with respect to the reference standard, and highlight key differences in the methods that allow for each method to have a unique niche as a tool for rapid identification of microbes in blood cultures.

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