Fully Automated EUCAST Rapid Antimicrobial Susceptibility Testing (RAST) from Positive Blood Cultures: Diagnostic Accuracy and Implementation

Cherkaoui, Abdessalam; Schorderet, Didier; Azam, Nouria; Crudeli, Luigi; Fernandez, José; Renzi, Gesuèle; Fischer, Adrien; Schrenzel, Jacques

doi:10.1128/jcm.00898-22

Cited by 13 publications

(4 citation statements)

References 17 publications

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“…The biggest problem we encountered for this bacterial species was that the diameter of the inhibition zone was not formed in many studies. Although Cherkaoui reported that this problem could be solved by prolonging the incubation period while evaluating the susceptibility results of ceftazidime and cefepime in RAST studies for P. aeruginosa, we found that prolonging the incubation period did not lead to a change in the results in our study (Cherkaoui et al 2022). ).…”

Section: Discussioncontrasting

confidence: 57%

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Evaluation of the compatibility of EUCAST Direct Rapid Antimicrobial Susceptibility Test (RAST) Method Results with Automated Systems in Positive-Signaling Blood Culture Bottles

Aydemir,

Şahin,

Köroğlu

2023

Preprint

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The aim of this study is to compare the RAST results with the Vitek 2 automatic system and evaluate its effectiveness. Total of 76 strains, including anonymous 15 Pseudomonas aeruginosa, 24 Escherciae coli, 16 Klebsiella pneumoniae, 6 Staphylococcus aureus, 11 Enterococcus faecalis, 1 Streptococcus pneumoniae, 3 Acinetobacter baumanii, found in the laboratory culture collection was included in the study. Rapid Antimicrobial Susceptibility Test (RAST) was performed in accordance with European Committee on Antimicrobial Susceptibility Testing (EUCAST) recommendations. A 10 µg ceftazidime disk was used for the detection of Extended Spectrum Beta-Lactamase (ESBL) by the RAST method. After incubation, it was interpreted as susceptible (S), resistant (R) and technical uncertainty area (ATU) according to EUCAST RAST v.1.1 breakpoint tables. Categorical results in 4, 6, 8 and 20 hours incubation were compared with vitek 2 automated system results. 581 disc diffusion studies were performed for all strains. Measurable zone diameter of inhibition occurred in 444 (76.4%) disc studies. The agreement between the results of the studies evaluated as sensitive and resistant by RAST with the results of the Vitek 2 automated system was found to be 98.4%. Compatibility with Vitek 2 automated system at the fourth hour was 98.1%; it was 97.9% at the sixth hour and 100% at the eighth hour. Our study shows that the RAST results are quite compatible with the conventional method. Therefore, although there are difficulties in routine laboratory practice, the results obtained with RAST show that it will provide rapid evaluation of empirical antibiotic therapy in bloodstream infections.

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Section: Discussioncontrasting

confidence: 57%

“…This poses di culties in evaluation for this antibiotic. Cherkaoui et al They reported that it is not correct to use RAST for imipenem and this antibiotic be excluded from the antibiotic panel to be tested for P. aeruginosa (Cherkaoui et al 2022). However, our results for meropenem were quite promising for P. aeruginosa.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the compatibility of EUCAST Direct Rapid Antimicrobial Susceptibility Test (RAST) Method Results with Automated Systems in Positive-Signaling Blood Culture Bottles

Aydemir,

Şahin,

Köroğlu

2023

Preprint

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“…A minor limitation of the study is the fact that the workflow for positive stool samples did not reach the predefined TAT goal of 65 h. However, stool samples represent only 4% of the caseload, and only 5% of them are positive, which makes the standardization of the workflow for these isolated specimens difficult. Furthermore, while previous studies by Cherkaoui and colleagues also highlighted the potential of automation to reduce TAT for other critical samples such as blood culture ( 33 ), the caseload for this sample type in the JCS laboratory was too low to be included in the present study. Moreover, the present study looked at the impact of a bundled intervention, i.e., implementation of WASPLab and VITEK MS systems.…”

Section: Discussionmentioning

confidence: 91%

Conversion of a classical microbiology laboratory to a total automation laboratory enhanced by the application of lean principles

Trigueiro,

Oliveira,

Rodrigues

et al. 2024

Microbiol Spectr

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Laboratory automation in microbiology improves productivity and reduces sample turnaround times (TATs). However, its full potential can be unlocked through the optimization of workflows by adopting lean principles. This study aimed to explore the relative impact of laboratory automation and continuous improvement events (CIEs) on productivity and TATs. Laboratory automation took place in November 2020 and consisted of the introduction of WASPLab and VITEK MS systems. CIEs were run in May and September 2021. Before the conversion, the laboratory processed about ~492 samples on weekdays and had 10 full-time equivalent (FTE) staff for a productivity of 49 samples/FTE/day. In March 2021, after laboratory automation, the caseload went up to ~621 while the FTEs decreased to 8.5, accounting for productivity improvement to 73 samples/FTE/day. The hypothetical productivity went up to 110 samples/FTE/day following CIEs, meaning that the laboratory could at that point deal with a caseload increase to ~935 with unchanged FTEs. Laboratory conversion also led to an improvement in TATs for all sample types. For vaginal swabs and urine samples, median TATs decreased from 70.3 h [interquartile range (IQR): 63.5–93.1] and 73.7 h (IQR: 35.6–50.7) to 48.2 h (IQR: 44.8–67.7) and 40.0 h (IQR: 35.6–50.7), respectively. Automation alone was responsible for 37.2% and 75.8% of TAT reduction, respectively, while the remaining reduction of 62.8% and 24.2%, respectively, was achieved due to CIEs. The laboratory reached productivity and TAT goals predefined by the management after CIEs. In conclusion, automation substantially improved productivity and TATs, while the subsequent implementation of lean management further unlocked the potential of laboratory automation. IMPORTANCE In this study, we combined total laboratory automation with lean management to show that appropriate laboratory work organization enhanced the benefit of the automation and substantially contributed to productivity improvements. Globally, the rapid availability of accurate results in the setting of a clinical microbiology laboratory is part of patient-centered approaches to treat infections and helps the implementation of antibiotic stewardship programs backed by the World Health Organization. Locally, from the point of view of laboratory management, it is important to find ways of maximizing the benefits of the use of technology, as total laboratory automation is an expensive investment.

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“…Newly developed tools, like the Pheno® system (Accelerate Diagnostics), or Vitek® Reveal™ (Biomérieux) offer rAST results in 7h and 5.5h, respectively. EUCAST RAST disk diffusion can deliver even faster AST results (as early as 4h), comes at a low cost and has proven to be a valuable tool [8][9][10], but does not provide quantitative MIC values, is fairly laborious with exact intervals and manual reading (although automation is possible [11,12]), as well as only providing breakpoints for a selection of species and antibiotic agents.…”

Section: Introductionmentioning

confidence: 99%

A multicenter evaluation of a novel microfluidic rapid AST assay for Gram-negative bloodstream infections

Berinson,

Davies,

Torpner

et al. 2024

Preprint

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ObjectivesCommon phenotypic methods for antibiotic susceptibility testing (AST) of bacteria are slow, labour intensive and displays considerable technical variability. The QuickMIC system provides rapid AST using a microfluidic linear gradient. Here we evaluate the performance of QuickMIC at four different laboratories with regards to speed, precision, accuracy, and reproducibility in comparison to broth microdilution (BMD).MethodsSpiked blood cultures (n=411) and clinical blood cultures (n=148) were tested with the QuickMIC Gram negative (GN) panel and compared with BMD for the 12 on-panel antibiotics, and 10 defined strains were run at each site to measure reproducibility. Logistic and linear regression analysis was applied to explore factors affecting assay performance.ResultsThe overall essential agreement (EA) and categorical agreement (CA) between QuickMIC and BMD were 95.6% and 96.0%, respectively. Very major error (VME), Major error (ME) and minor error (mE) rates were 1.0, 0.6 and 2.4%, respectively. Inter-laboratory reproducibility between the sites was high at 98.9% using the acceptable standard of ±1 log2 unit. The mean in-instrument analysis time overall was 3h 13 min (SD: 29 min). Regression analysis indicated that QuickMIC is robust with regards to initial inoculate and delay time after blood culture positivity.ConclusionsWe conclude that QuickMIC can be used to rapidly measure MIC directly from blood cultures in clinical settings, with a high reproducibility, precision, and accuracy. The microfluidics-generated linear gradient ensures high repeatability and reproducibility between laboratories, thus allowing a high level of trust in MIC values from single testing, at the cost of reduced measurement range compared to BMD.

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Fully Automated EUCAST Rapid Antimicrobial Susceptibility Testing (RAST) from Positive Blood Cultures: Diagnostic Accuracy and Implementation

Cited by 13 publications

References 17 publications

Evaluation of the compatibility of EUCAST Direct Rapid Antimicrobial Susceptibility Test (RAST) Method Results with Automated Systems in Positive-Signaling Blood Culture Bottles

Evaluation of the compatibility of EUCAST Direct Rapid Antimicrobial Susceptibility Test (RAST) Method Results with Automated Systems in Positive-Signaling Blood Culture Bottles

Conversion of a classical microbiology laboratory to a total automation laboratory enhanced by the application of lean principles

A multicenter evaluation of a novel microfluidic rapid AST assay for Gram-negative bloodstream infections

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