Rapid Antimicrobial Susceptibility Testing Research Articles

Clinical Practice: Estimating the Breakpoints for EUCAST Fast Antimicrobial Susceptibility Testing Using Flagged BacT/Alert Blood Culture Bottles

<i>Introduction</i>: The escalating prevalence of multidrug resistance is a global threat to human health particularly in critically ill patients with bloodstream infections (BSIs). Delay in the administration of the appropriate antimicrobial treatment is associated with higher mortality rates and adverse consequences. This study attempted to estimate the rapid antimicrobial susceptibility testing (RAST) breakpoints directly from flagged BacT/Alert blood culture bottles in clinical practice. <i>Material & Methods</i>: A descriptive, cross-sectional study conducted at a tertiary care hospital in Delhi over a period of two months. The RAST was performed directly from the clinical samples for blood cultures received in our laboratory in parallel with the routine antimicrobial testing as per standard CLSI guidelines. Blood cultures were routinely incubated in BacT/Alert 3D. The inhibition zones were read at 4, 6, 8 and 16-20 hour of incubation as per European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The identification of the isolates was confirmed by Vitek-2 compact system. <i>Results</i>: In our study, the area of technical uncertainty (ATU) percentage was initially high at 4 hours but decreased significantly in later incubation periods. At 4 hours, none of the <i>S. aureus</i> isolates showed >90% categorical agreement (CA) for any antimicrobial tested. However, clindamycin achieved the highest CA (100%) at 6 hours and 90% thereafter, with no very major errors (VME) or major error (ME). Cefoxitin required 8 hours to reach >90% CA, with no VME observed at any time point, but up to 75% ME at 8 hours. At 4 hours, most antimicrobials had high (>1.5%) rates of VME among <i>Enterobacteriales</i>. By 6 hours, only Meropenem and Gentamicin had >90% CA, with no VME observed for other antibiotics. <i>Conclusion</i>: The RAST method is relatively easy to implement in clinical microbiology labs, offering cost-effectiveness, simplicity, and rapid results, especially in resource-limited settings. However, reporting RAST results can be complex due to potential challenges with CA, VME, and ME, particularly in the initial hours of incubation and within the ATU.

Rapid detection of microbial antibiotic susceptibility via deep learning supported analysis of angle-resolved scattered-light images of picoliter droplet cultivations

The progressive increase in microbial resistance to antibiotics is a global health threat that requires solutions for rapid and reliable determination of antibiotic susceptibility in order to select appropriate antibiotics and dosages prior to treatment. We have established a screening platform that enables the detection of cell growth after just a few cell divisions. Our methodological approach for a robust phenotypic antibiotic susceptibility testing is based on the innovative combination of three cutting-edge technologies: (i) a high-throughput microfluidic platform where individual bacterial cells are encapsulated in picoliter-sized droplets, (ii) a 2D angle-resolved light scattering sensor to perform label-free hourly screening of the droplets, and (iii) a computational image analysis approach based on convolutional neural networks to evaluate the dynamics of microbial growth in droplets. For the gram-positive Staphylococcus aureus and gram-negative Escherichia coli, we demonstrate that microbial growth in droplets can be successfully detected within one to two hours. Furthermore, the potential of this platform for rapid phenotypic antibiotic susceptibility testing is demonstrated as a proof-of-concept with the clinically relevant bacterium S. aureus under various concentrations of the antibiotic tetracycline. Notably, we reach a robust phenotypic decision regarding the sensitivity to this antibiotic within two hours.

Validation of EUCAST rapid antimicrobial susceptibility testing directly from positive blood cultures in a non-automated lab setting

ABSTRACT Introduction To speed up antimicrobial susceptibility testing (AST), the European Committee on Antimicrobial Susceptibility Testing (EUCAST) proposed rapid AST (RAST), a disk diffusion method to be read after 4, 6 and 8 hours of incubation. We investigated the feasibility of implementation of RAST in a non-automated lab setting. Materials & methods To this end, reference strains as well as a variety of clinical and resistant strains were used to spike sterile hemocultures (BioMérieux BACT/ALERT 3D® and Becton Dickinson BACTEC FX® systems), followed by RAST in comparison to classical long-incubation AST. Results & conclusion Our results with reference strains show that reading RAST after 4 hours is frequently too soon to obtain clinical results, and that Streptococcus pneumoniae reference strain did yield readable inhibition zones in RAST when harvested from BioMérieux BACT/ALERT 3D® bottle cultures. In a wider panel of strains, Gram positives RAST results were very similar to standard AST, while with Gram negative species errors were more frequently observed, limiting clinical implementation.

Budget impact analysis on the use of Sysmex PA-100 AST system as a point of care for uncomplicated urinary tract infections detection and treatment in Spanish females

Objective Efficient diagnostic methods, such as the Sysmex PA-100, provide rapid antimicrobial susceptibility test results directly from urine samples with high sensitivity and specificity, and improve treatment recommendations. Our study analyzes the economic impact of integrating the Sysmex PA-100 to assess its potential benefits and cost implications for uncomplicated urinary tract infection (uUTI) management in Spain. Methodology A budget impact model was developed using a decision tree framework to compare current UTI management practices with a new scenario incorporating the Sysmex PA-100. The clinical inputs were extracted from published literature. The model, representing adult females with uUTIs, assessed direct medical and indirect costs over three years, including diagnostic procedures, treatment costs, staff time costs, and productivity loss. The cost data was captured from two Spanish hospitals. Two scenario analyses were conducted in the model: scenario A included costs for antimicrobial resistance (AMR) emergence in patients receiving unnecessary empirical antibiotics, whereas scenario B assumed no AMR costs. Results In scenario A, 100% implementation of PA-100 within various Spanish healthcare settings over one year resulted in total cost savings of EUR 323,657,712 (EUR 119.10 per patient per year). The total overall cost savings attributable to the implementation of PA-100 over three years were EUR 970,973,137. In scenario B, the total annual savings were EUR 4,254,795 (EUR 1.57 per patient per year), and the 3-year savings were EUR 12,764,385. Conclusion The adoption of this point-of-care system results in overall cost savings, driven by reductions in direct and indirect costs related to UTI management. The model highlights potential savings over three years owing to appropriate rapid management (reduction in time to diagnosis and treatment, which leads to fewer complications and secondary infections) and reduced staff time and productivity loss costs. These findings support the potential benefits of adopting the Sysmex PA-100 to enhance UTI management and allocate healthcare resource utilization in Spain.

Clinical pilot of bacterial transcriptional profiling as a combined genotypic and phenotypic antimicrobial susceptibility test.

Antimicrobial resistance is a growing health threat, but standard methods for determining antibiotic susceptibility are slow and can delay optimal treatment, which is especially consequential in severe infections such as bacteremia. Novel approaches for rapid susceptibility profiling have emerged that characterize either bacterial response to antibiotics (phenotype) or detect specific resistance genes (genotype). Genotypic and Phenotypic AST through RNA detection (GoPhAST-R) is a novel assay, performed directly on positive blood cultures, that integrates rapid transcriptional response profiling with the detection of key resistance gene transcripts, thereby providing simultaneous data on both phenotype and genotype. Here, we performed the first clinical pilot of GoPhAST-R on 42 positive blood cultures: 26 growing Escherichia coli, 15 growing Klebsiella pneumoniae, and 1 with both. An aliquot of each positive blood culture was exposed to nine different antibiotics, lysed, and underwent rapid transcriptional profiling on the NanoString platform; results were analyzed using an in-house susceptibility classification algorithm. GoPhAST-R achieved 95% overall agreement with standard antimicrobial susceptibility testing methods, with the highest agreement for beta-lactams (98%) and the lowest for fluoroquinolones (88%). Epidemic resistance genes including the extended spectrum beta-lactamase blaCTX-M-15 and the carbapenemase blaKPC were also detected within the population. This study demonstrates the clinical feasibility of using transcriptional response profiling for rapid resistance determination, although further validation with larger and more diverse bacterial populations will be essential in future work. GoPhAST-R represents a promising new approach for rapid and comprehensive antibiotic susceptibility testing in clinical settings.IMPORTANCEExposure to antibiotics causes differential transcriptional signatures in susceptible vs resistant bacteria. These differences can be leveraged to rapidly predict resistance profiles of Escherichia coli and Klebsiella pneumoniae in clinically positive blood cultures.

Exploiting β-Lactams-Induced Lysis and DNA Fragmentation for Rapid Molecular Antimicrobial Susceptibility Testing of Neisseria Gonorrhoeae via Dual-Digital PCR.

The evolution of antimicrobial resistance (AMR) presents substantial challenges to global medical health systems. Neisseria gonorrhoeae (N. gonorrhoeae), in particular, has developed resistance to all currently available antimicrobials. Addressing this issue necessitates not only discovering new antimicrobials but also deepening the understanding of bacterial responses to these agents, which can lead to new markers for rapid antimicrobial susceptibility testing (AST). Such advancements can enhance treatment outcomes and promote antimicrobial stewardship. In this study, single-cell techniques, including live-cell imaging, flow cytometry, and digital polymerase chain reaction (PCR) are utilized, to investigate the lysis dynamics and molecular features of N. gonorrhoeae upon exposure to β-lactam antimicrobials. Distinct patterns of bacterial lysis and DNA fragmentation are uncovered in susceptible strains. Leveraging these discoveries, A microfluidic dual-digital PCR approach that combines single-cell and single-molecule analyses, facilitating rapid and efficient phenotypic molecular AST for N. gonorrhoeae against β-lactams is developed. This proof-of-concept validation demonstrates the effectiveness of the method in accessing antimicrobial susceptibility across a range of bacterial strains, contributing valuable insights for advancing the battle against AMR.

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

Increasing antimicrobial resistance underscores the need for new diagnostic solutions to guide therapy, but traditional antimicrobial susceptibility testing (AST) is often inadequate in time-critical diseases such as sepsis. This work presents a novel and rapid AST system with a rapid turnaround of results, which may help reduce the time to guided therapy, possibly allowing early de-escalation of broad-spectrum empirical therapy as well as rapid adjustments to treatments when coverage is lacking.

Dual-modal detection of antimicrobial susceptibility in pathogenic bacteria based on the high-throughput microfluidic platform

For pathogenic bacterial infectious diseases such as sepsis, accurate and rapid antimicrobial susceptibility testing (AST) plays an important role in improving antimicrobial screening and clinical outcomes. Traditional culture-based AST assays have the limitations of time-consuming, labor-intensive, expensive, and consuming reagents. In this work, a simple, fast, high-throughput microfluidic platform integrated with isolation, identification, and detection functions was designed for antibiotic susceptibility analysis in pathogenic bacteria. For the above purpose, MnO2@ZIF-90 nanoprobes with dual functions of nanozyme and fluorescence were prepared for visual eye or RGB analysis through a smartphone APP. More importantly, the redox activity of bacterial membrane in active pathogenic bacteria could decompose the MnO2 of MnO2@ZIF-90 nanoprobes and reduce the enzyme-like activity, which weakens the colorimetric signal of Timebox. Meanwhile, the ATP released from active pathogenic bacteria further triggered the breakdown of the inner ZIF-90 layer, generating a fluorescence signal. Therefore, a dual detection combining colorimetric and fluorescence was used to perform more accurate and reliable antibiotic susceptibility analysis of pathogenic bacteria. With the proposed microfluidic platform, a low detection of 10 CFU mL−1 bacteria and fast AST results were achieved within 5 min. The clinical applicability of the platform was further demonstrated through the analysis of clinical samples. This work provides a low-cost, easy-to-operation, fast-response, and high-throughput platform for the AST assays in pathogenic bacterial infectious diseases such as sepsis.

A-273 Rapid, Portable Invasive Fungal Infection Diagnostic and Candida Antimicrobial Susceptibility Testing

Abstract Background Traumatic wounds are associated with a higher risk of invasive fungal infections (IFI), which lead to a significant increase in amputation or death. Actionable treatment decisions are hampered because true infections can be difficult to differentiate from external wound contaminates, and tissue biopsy and quantification of fungal load is required to determine if treatment is necessary, which currently takes several days. GeneCapture is developing the CAPTURE 60-minute, portable infection identification platform to detect infectious levels of common fungi including the genera Aspergillus, Fusarium, and Scedosporium, the family Herpotrichiellaceae, and the order Mucorales. The company is also pursuing rapid identification and antimicrobial susceptibility testing for Candida species from multiple infection types. Methods This study seeks to determine the Limit of Detection (LoD), sensitivity and specificity of the CAPTURE ID assay for fungal pathogens. Since tissue biopsy samples must be used to assess the presence of IFI in wounds, GeneCapture has developed a manual process for the crude homogenization of muscle tissue to allow this matrix to be used as the starting sample for the ID assay. Mock samples were tested for inclusivity and exclusivity on a series of IFI ID panels against multiple strains of the included fungi, against fungi not yet specifically detected on the panel, and against bacteria that commonly infect wounds. While the LoD for yeasts may be determined in CFU/mL, there is no similar, easy-to-define metric for molds. GeneCapture has developed a quantitative PCR method to detect the single copy beta-tubulin gene to roughly correlate fungal dry mass and nuclei number to assay signal for molds cultured in Potato Dextrose Broth. Determining beta-tubulin copy numbers for extracts from mock samples then allowed detection of the progression of IFI over the course of infection. Lastly, antimicrobial susceptibility testing (AST) was performed on two species of Candida to validate utilizing GeneCapture’s rapid phenotypic AST method for fungal infections. Results To date, the CAPTURE ID panel has been tested against 27 included or excluded strains of fungi or bacteria with 97% sensitivity and 100% specificity. The current LoD for mold organisms varies from approximately 1,000 nuclei for Aspergillus species, to 100,000 nuclei for Fusarium species. Additional work to understand this range is underway. Lastly, we have correctly determined the susceptibility of Candida species using our novel approach within 4-6 hours. Conclusions GeneCapture’s ID and AST technology offer a unique solution to address the increasing prevalence of fungal infections. Our platform can identify the most common fungal components in a wound within 60 minutes of receiving a tissue biopsy sample. Candida infections occur across multiple matrices and rapidly identifying the species of Candida and then determining its phenotypic susceptibility profile will have a large impact on treating these difficult pathogens.

Label-free single-cell antimicrobial susceptibility testing in droplets with concentration gradient generation.

Bacterial communities exhibit significant heterogeneity, resulting in the emergence of specialized phenotypes that can withstand antibiotic exposure. Unfortunately, the existence of subpopulations resistant to antibiotics often goes unnoticed during treatment initiation. Thus, it is crucial to consider the concept of single-cell antibiotic susceptibility testing (AST) to tackle bacterial infections. Nevertheless, its practical application in clinical settings is hindered by its inability to conduct AST efficiently across a wide range of antibiotics and concentrations. This study introduces a droplet-based microfluidic platform designed for rapid single-cell AST by creating an antibiotic concentration gradient. The advantage of a microfluidic platform is achieved by executing bacteria and antibiotic mixing, cell encapsulation, incubation, and enumeration of bacteria in a seamless workflow, facilitating susceptibility testing of each antibiotic. Firstly, we demonstrate the rapid determination of minimum inhibitory concentration (MIC) of several antibiotics with Gram-negative E. coli and Gram-positive S. aureus, which enables us to bypass the time-consuming bacteria cultivation, speeding up the AST in 3 h from 1 to 2 days of conventional methods. Additionally, we assess 10 clinical isolates including methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Staphylococcus aureus (MDRSA) against clinically important antibiotics for analyzing the MIC, compared to the gold standard AST method from the United States Clinical and Laboratory Standards Institute (CLSI), which becomes available only after 48 h. Furthermore, by monitoring single cells within individual droplets, we have found a spectrum of resistance levels among genetically identical cells, revealing phenotypic heterogeneity within isogenic populations. This discovery not only advances clinical diagnostics and treatment strategies but also significantly contributes to the field of antibiotic stewardship, underlining the importance of our approach in addressing bacterial resistance.

Barriers to implementation of rapid identification and antimicrobial susceptibility testing technologies in the clinical microbiology laboratory: an American perspective.

Clinical microbiology laboratories are responsible for confirming the aetiology of infectious diseases and providing antimicrobial susceptibility testing results. Traditional culture-based testing can be augmented by more rapid testing modalities to provide clinically actionable information as quickly as possible. Despite improvements in patient outcomes, many clinical microbiology laboratories are facing challenges to in-sourcing these technologies. Depending on a multitude of factors, including size, location and patient population served, these barriers may affect some laboratories and hospital systems to greater or lesser extents than others. It will be up to each individual facility to ascertain its ability to overcome barriers. To aid in this self-assessment, we present for thoughtful consideration a discussion of the barriers to implementation of rapid identification and antimicrobial susceptibility testing technologies, with specific attention to matters of financial cost, staff expertise, operational issues and stakeholder buy-in.

Retrospective evaluation of rapid genotypic ID and phenotypic AST systems on positive blood culture turnaround time and simulated potential impacts on bloodstream infection management

Abstract Background Bloodstream infections are linked to heightened morbidity and mortality rates. The consequences of delayed antibiotic treatment can be detrimental. Effective management of bacteraemia hinges on rapid antimicrobial susceptibility testing. Objectives This retrospective study examined the influence of the VITEK® REVEAL™ Rapid AST system on positive blood culture (PBC) management in a French tertiary hospital. Materials and methods Between November 2021 and March 2022, 79 Gram-negative monomicrobial PBC cases underwent testing with both VITEK®REVEAL™ and VITEK®2 systems. Results The study found that VITEK®REVEAL™ yielded better results than the standard of care, significantly shortening the time to result (7.0 h compared to 9.6 h) as well as the turnaround time (15 h compared to 31.1 h) when applied for all isolates. Conclusions This study implies that the use of VITEK®REVEAL™ enables swift adaptations of antibiotic treatment strategies. By considerably minimizing the turnaround time, healthcare professionals can promptly make necessary adjustments to therapeutic regimens. Notably, these findings underscore the potential of VITEK®REVEAL™ in expediting appropriate antibiotic interventions, even in less ideal conditions. Further studies in varied laboratory contexts are required to validate these encouraging outcomes.

Evaluating the impact of rapid antimicrobial susceptibility testing for bloodstream infections: a review of actionability, antibiotic use and patient outcome metrics.

Antimicrobial susceptibility testing (AST) is a core function of the clinical microbiology laboratory and is critical to the management of patients with bloodstream infections (BSIs) to facilitate optimal antibiotic therapy selection. Recent technological advances have resulted in several rapid methods for determining susceptibility direct from positive blood culture that can provide turnaround times in under 8 h, which is considerably shorter than conventional culture-based methods. As diagnostic results do not directly produce a medical intervention, actionability is a primary determinant of the effect these technologies have on antibiotic use and ultimately patient outcomes. Randomized controlled trials and observational studies consistently show that rapid AST significantly reduces time to results and improves antimicrobial therapy for patients with BSI across various methods, patient populations and organisms. To date, the clinical impact of rapid AST has been demonstrated in some observational studies, but randomized controlled trials have not been sufficiently powered to validate many of these findings. This article reviews various metrics that have been described in the literature to measure the impact of rapid AST on actionability, antibiotic exposure and patient outcomes, as well as highlighting how implementation and workflow processes can affect these metrics.

A comparative study of a rapid phenotypic antimicrobial susceptibility testing system directly from positive blood cultures to the disk diffusion and VITEK 2 methods

BackgroundSepsis is a life-threatening condition that impacts 49 million people annually and causes 11 million deaths worldwide. Surviving bloodstream infections (BSIs) depends on the rapid administration of effective antimicrobial treatment, underscoring a need for rapid antimicrobial susceptibility testing (AST). AimTo evaluate the performance of Quantamatrix's dRAST v2.5 system (Seoul, South Korea) for AST directly from positive blood cultures as compared to the Disk-Diffusion (DD) and VITEK 2 methods. MethodsThe study included 191 positive blood cultures from clinical samples and spiked blood culture bottles. Following Gram staining and species-level identification, AST was performed by VITEK 2 and standard DD methods using CLSI (2021) interpretation. ResultsdRAST demonstrated very good AST performance for a Gram-negative isolate, and good performance for Gram-positive isolates, meeting CLSI criteria for the acceptance of a new method. Antimicrobials that were not considered verified compared to VITEK 2 and DD were cefazolin, ceftazidime, meropenem, and trimethoprim/sulfamethoxazole for Gram-negatives and clindamycin, erythromycin, penicillin, and oxacillin for Gram-positives. dRAST ESBL detection results were strongly correlated with the ESBL phenotypes obtained with other methods. Additional resistance mechanisms were in concordance with traditional tests. ConclusionsdRAST demonstrated good AST performance, meeting CLSI criteria for most relevant antibiotics. dRAST was associated with a significant reduction in time-to-results, labor, and the subjectivity of result analyses, making it a valuable addition to efforts supporting the treatment of patients with bacteremia.AST (antimicrobial susceptibility test), blood culture, dRAST, rapid methods, sepsis, turnaround time (TAT).

Evaluating EUCAST rapid antimicrobial susceptibility test from positive neonatal blood culture directly against the golden standard disc diffusion method in a tertiary hospital

Evaluating EUCAST rapid antimicrobial susceptibility test from positive neonatal blood culture directly against the golden standard disc diffusion method in a tertiary hospital

A Comparative Study of Bacteriological Profile and Susceptibility Pattern by Rapid Direct Manual Identification and Antimicrobial Susceptibility Testing with Routine Blood Culture Method in Neonatal Septicemia.

A Comparative Study of Bacteriological Profile and Susceptibility Pattern by Rapid Direct Manual Identification and Antimicrobial Susceptibility Testing with Routine Blood Culture Method in Neonatal Septicemia.

Platinum nanoparticles-based electrochemical H2O2 sensor for rapid antibiotic susceptibility testing

With the increase of antimicrobial resistance, rapid antibiotic susceptibility testing (AST) to guide precise antibiotic administration has become increasingly important. However, current gold standard AST approaches tend to take up to 24–48 h. In this work, based on the nature of catalase-positive bacteria decomposing H2O2, we developed a rapid, portable, straightforward, and cost-effective phenotypic AST approach by detecting residual H2O2 using a Pt nanoparticles-based electrochemical sensor. The pulse current of the sensor exhibited a linear increase with rising H2O2 concentration, demonstrating a high sensitivity of ∼382.2 μA cm−2 mM−1. This approach showed superb diagnostic performance, with an area under the curve of 1 for 24 clinical samples of Escherichia coli and Staphylococcus aureus, with a total detection time of 60 and 45 min, respectively. Furthermore, the performance of the sensor showed no degradation even after 100 detections, promising a substantial reduction in AST costs. Overall, the proposed approach exhibited immense potential for diagnosing bacterial antibiotic resistance.

Rapid Antimicrobial Susceptibility Test of Helicobacter pylori to Metronidazole via Single-Cell Raman Spectrometry.

Metronidazole is a first-line antibiotic to treat Helicobacter pylori infections. However, the Clinical Laboratory Standards Institute guidelines recommend against using antimicrobial susceptibility test (AST) to test metronidazole resistance, due to the unreliable predictive power which can result in treatment failure. The aim of this study was to establish an 8-h, metabolic-phenotype based AST for H. pylori metronidazole susceptibility using D2O-probed Raman microspectroscopy. Minimal inhibitory concentration (MIC) measured by conventional AST (E-test) were compared with expedited MIC via metabolic activity (eMIC-MA) for 10 H. pylori isolates. Raman barcodes of cellular-response to stress (RBCS) incorporating protein and carbohydrate Raman bands, were utilized to identify a biomarker to distinguish metronidazole susceptibility. Specifically, eMIC-MA produces metronidazole susceptibility results showing 100% agreement with E-test, and determines the bactericidal dosage for both high- and low-level resistant H. pylori strains. In addition, RBCS not just reliably distinguish between metronidazole-susceptible and -resistant strains, but reveal their distinct mechanisms in bacterial responses to metronidazole. The speed, accuracy, low cost, and rich information content that reveals the mode-of-action of drugs suggest the method's value in guiding metronidazole prescriptions for H. pylori eradication and in rapid screening based on drug-resistance mechanism.

Evaluation of the Reveal® AST (SPECIFIC) for Antimicrobial Susceptibility Testing from Positive Blood Culture Spiked with Carbapenem-Resistant Isolates.

As bloodstream infections and associated septic shock are common causes of mortality in hospitals, rapid antibiotic susceptibility testing (AST) performed directly on positive blood cultures is needed to implement an efficient therapy in clinical settings. We evaluated the Reveal® rapid AST system on a collection of 197 fully characterized carbapenem-resistant Enterobacterales, including 177 carbapenemase producers (CPE) spiked in blood culture bottles. The clinical categorization based on the Minimal Inhibitory Concentration (MIC) determination of eighteen antimicrobial molecules was compared to the clinical categorization based on the disk diffusion assay as a reference. The Reveal AST system provided results within a mean time to result of 5 h. Overall, the categorical agreement (CA) between the two techniques was 94.1%. The rates of very major errors (VMEs), major errors (MEs) and minor errors (mEs) were 3.8%, 3.7% and 5.6%, respectively. Imipenem was the antimicrobial with the lowest CA rate (78.7%), with rates of 15% VMEs and 10.7% MEs, but the performances were better when considering only the non-CPE category (CA of 89%). On this resistant collection of Enterobacterales with numerous acquired β-lactamases, the Specific Reveal assay proved to be useful for a rapid determination of AST compatible with a quick adaptation of the patient's antimicrobial treatment.

Rapid Phenotypic and Genotypic Antimicrobial Susceptibility Testing Approaches for Use in the Clinical Laboratory.

The rapid rise in increasingly resistant bacteria has become a major threat to public health. Antimicrobial susceptibility testing (AST) is crucial in guiding appropriate therapeutic decisions and infection prevention practices for patient care. However, conventional culture-based AST methods are time-consuming and labor-intensive. Therefore, rapid AST approaches exist to address the delayed gap in time to actionable results. There are two main types of rapid AST technologies- phenotypic and genotypic approaches. In this review, we provide a summary of all commercially available rapid AST platforms for use in clinical microbiology laboratories. We describe the technologies utilized, performance characteristics, acceptable specimen types, types of resistance detected, turnaround times, limitations, and clinical outcomes driven by these rapid tests. We also discuss crucial factors to consider for the implementation of rapid AST technologies in a clinical laboratory and what the future of rapid AST holds.