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Kim T, Kang M, Shim H, Kang O, Huh H, Lee N. Evaluation of the QMAC-dRAST System Version 2.5 for Rapid Antimicrobial Susceptibility Testing of Gram-Negative Bacteria From Positive Blood Culture Broth and Subcultured Colony Isolates. J Clin Lab Anal 2024; 38:e25043. [PMID: 38804639 PMCID: PMC11137843 DOI: 10.1002/jcla.25043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 04/21/2024] [Accepted: 04/25/2024] [Indexed: 05/29/2024] Open
Abstract
BACKGROUND Rapid antimicrobial susceptibility testing (AST) for bloodstream infections (BSIs) facilitates the optimization of antimicrobial therapy, preventing antimicrobial resistance and improving patient outcomes. QMAC-dRAST (QuantaMatrix Inc., Korea) is a rapid AST platform based on microfluidic chip technology that performs AST directly using positive blood culture broth (PBCB). This study evaluated the performance of QMAC-dRAST for Gram-negative bacteria using PBCB and subcultured colony isolates, comparing it with that of VITEK 2 (bioMérieux, France) using broth microdilution (BMD) as the reference method. METHODS We included 141 Gram-negative blood culture isolates from patients with BSI and 12 carbapenemase-producing clinical isolates of Enterobacterales spiked into blood culture bottles. QMAC-dRAST performance was evaluated using PBCB and colony isolates, whereas VITEK 2 and BMD were tested only on colony isolates. RESULTS For PBCB, QMAC-dRAST achieved 92.1% categorical agreement (CA), 95.3% essential agreement (EA), with 1.8% very major errors (VMEs), 3.5% major errors (MEs), and 5.2% minor errors (mEs). With colony isolates, it exhibited 92.5% CA and 95.1% EA, with 2.0% VMEs, 3.2% MEs, and 4.8% mEs. VITEK 2 showed 94.1% CA and 96.0% EA, with 4.3% VMEs, 0.4% MEs, and 4.3% mEs. QMAC-dRAST yielded elevated error rates for specific antimicrobial agents, with high VMEs for carbapenems and aminoglycosides. The median time to result for QMAC-dRAST was 5.9 h for PBCB samples and 6.1 h for subcultured colony isolates. CONCLUSIONS The QMAC-dRAST system demonstrated considerable strengths and comparable performance to the VITEK 2 system; however, challenges were discerned with specific antimicrobial agents, underlining a necessity for improvement.
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Affiliation(s)
- Tae Yeul Kim
- Department of Laboratory Medicine and Genetics, Samsung Medical CenterSungkyunkwan University School of MedicineSeoulRepublic of Korea
| | - Minhee Kang
- Biomedical Engineering Research Center, Smart Healthcare Research InstituteSamsung Medical CenterSeoulRepublic of Korea
- Department of Medical Device Management and Research, Samsung Advanced Institute for Health Science & TechnologySungkyunkwan UniversitySeoulRepublic of Korea
| | - Hyang Jin Shim
- Center for Clinical Medicine, Samsung Biomedical Research InstituteSamsung Medical CenterSeoulRepublic of Korea
| | - On‐Kyun Kang
- Department of Laboratory Medicine and Genetics, Samsung Medical CenterSungkyunkwan University School of MedicineSeoulRepublic of Korea
| | - Hee Jae Huh
- Department of Laboratory Medicine and Genetics, Samsung Medical CenterSungkyunkwan University School of MedicineSeoulRepublic of Korea
- Department of Medical Device Management and Research, Samsung Advanced Institute for Health Science & TechnologySungkyunkwan UniversitySeoulRepublic of Korea
| | - Nam Yong Lee
- Department of Laboratory Medicine and Genetics, Samsung Medical CenterSungkyunkwan University School of MedicineSeoulRepublic of Korea
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2
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Turbett SE, Banach DB, Bard JD, Gandhi RG, Letourneau AR, Azar MM. Rapid antimicrobial resistance detection methods for bloodstream infection in solid organ transplantation: Proposed clinical guidance, unmet needs, and future directions. Transpl Infect Dis 2023; 25:e14113. [PMID: 37594214 DOI: 10.1111/tid.14113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/14/2023] [Accepted: 07/28/2023] [Indexed: 08/19/2023]
Abstract
Recent advances in antimicrobial resistance detection have spurred the development of multiple assays that can accurately detect the presence of bacterial resistance from positive blood cultures, resulting in faster institution of effective antimicrobial therapy. Despite these advances, there are limited data regarding the use of these assays in solid organ transplant (SOT) recipients and there is little guidance on how to select, implement, and interpret them in clinical practice. We describe a practical approach to the implementation and interpretation of these assays in SOT recipients using the best available data and expert opinion. These findings were part of a consensus conference sponsored by the American Society of Transplantation held on December 7, 2021 and represent the collaboration between experts in transplant infectious diseases, pharmacy, antimicrobial and diagnostic stewardship, and clinical microbiology. Areas of unmet need and recommendations for future investigation are also presented.
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Affiliation(s)
- Sarah E Turbett
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - David B Banach
- Department of Medicine, University of Connecticut School of Medicine, Farmington, Connecticut, USA
| | - Jennifer Dien Bard
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, California, USA
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Ronak G Gandhi
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Pharmacy, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Alyssa R Letourneau
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Marwan M Azar
- Department of Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, Connecticut, USA
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
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3
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Gallois E, Fihman V, Danjean M, Gomart C, Kimseng H, Le Guen R, Royer G, Woerther PL. QMAC-dRAST for the direct testing of antibiotic susceptibility for Enterobacterales in positive blood-culture broth: a comparison of the performances with the MicroScan system and direct disc diffusion testing methods. J Antimicrob Chemother 2023; 78:684-691. [PMID: 36611274 DOI: 10.1093/jac/dkac441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 12/09/2022] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES To evaluate the performances of the QMAC-dRAST GN (Gram-negative) kit for rapid antimicrobial sensitivity testing (AST) and two other methods, directly on positive blood-culture broth (PBCB), by comparison with a reference method: the MicroScan method based on broth microdilution on colonies isolated on PBCB subculture. METHODS In total, 156 samples were collected prospectively from blood cultures positive for a Gram-negative rod. Each sample was tested with four AST techniques: (i) the QMAC dRAST GN kit, (ii) the disc diffusion (DD) method, (iii) the MicroScan method applied directly to PBCB; and (iv) MicroScan with isolates from PBCB subculture, as a reference. RESULTS For 124 PBCB containing Enterobacterales, overall essential agreement (EA) and categorical agreement (CA) between the QMAC-dRAST on PBCB and the reference reached 95.7% and 93.5%, respectively. There were 3.0% very major errors (VME), 4.0% major errors (ME) and 2.8% minor errors (mE). A comparison of MicroScan on PBCB and the reference yielded 98.8% EA, 98.5% CA, and rates of 0.6% VME, 0.9% ME and 0.7% mE. The DD method on PBCB gave a CA of 95.8% and rates of 1.7% for VME, 2.0% for ME and 1.9% for mE. Results were obtained more rapidly for QMAC-dRAST (median of 6 h 37 min versus 18 h for the MicroScan and DD methods on PBCB). CONCLUSIONS The QMAC-dRAST system provided rapid results well correlated with the reference method on PBCB containing Enterobacterales. Given the shorter time-to-results, the QMAC-dRAST system constitutes a fast and reliable alternative to conventional AST methods.
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Affiliation(s)
- E Gallois
- AP-HP, Henri Mondor Hospital, Department of Prevention, Diagnosis and Treatment of Infections, Paris-Est-Créteil University, Créteil, France
| | - V Fihman
- AP-HP, Henri Mondor Hospital, Department of Prevention, Diagnosis and Treatment of Infections, Paris-Est-Créteil University, Créteil, France.,EA 7380 Dynamyc, EnvA, Paris-Est University, 94000 Créteil, France
| | - M Danjean
- AP-HP, Henri Mondor Hospital, Department of Prevention, Diagnosis and Treatment of Infections, Paris-Est-Créteil University, Créteil, France.,EA 7380 Dynamyc, EnvA, Paris-Est University, 94000 Créteil, France
| | - C Gomart
- AP-HP, Henri Mondor Hospital, Department of Prevention, Diagnosis and Treatment of Infections, Paris-Est-Créteil University, Créteil, France
| | - H Kimseng
- AP-HP, Henri Mondor Hospital, Department of Prevention, Diagnosis and Treatment of Infections, Paris-Est-Créteil University, Créteil, France
| | - R Le Guen
- AP-HP, Henri Mondor Hospital, Department of Prevention, Diagnosis and Treatment of Infections, Paris-Est-Créteil University, Créteil, France
| | - G Royer
- AP-HP, Henri Mondor Hospital, Department of Prevention, Diagnosis and Treatment of Infections, Paris-Est-Créteil University, Créteil, France.,EA 7380 Dynamyc, EnvA, Paris-Est University, 94000 Créteil, France
| | - P L Woerther
- AP-HP, Henri Mondor Hospital, Department of Prevention, Diagnosis and Treatment of Infections, Paris-Est-Créteil University, Créteil, France.,EA 7380 Dynamyc, EnvA, Paris-Est University, 94000 Créteil, France
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4
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Payen M, Gaudart A, Legueult K, Kasprzak J, Emery A, Mutambayi G, Pradier C, Robin F, Lotte R, Ruimy R. Evaluation of an Antibiotic Susceptibility Testing Method on Enterobacterales-Positive Blood Cultures in Less Than 8 h Using the Rapid Mueller-Hinton Diffusion Method in Conjunction with the SIRscan 2000 Automatic Reading Device. Microorganisms 2022; 10:microorganisms10071377. [PMID: 35889096 PMCID: PMC9320083 DOI: 10.3390/microorganisms10071377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/29/2022] [Accepted: 07/05/2022] [Indexed: 02/04/2023] Open
Abstract
Enterobacterales bloodstream infections are life-threatening and require rapid, targeted antibiotherapy based on antibiotic susceptibility testing (AST). A new method using Muller-Hinton Rapid-SIR (MHR-SIR) agar (i2a, Montpellier, France) allows complete direct AST (dAST) to be read from positive blood culture bottles (BCBs) for all Enterobacterales species after 6-8 h of incubation. We evaluated (i) the performance of dAST from positive BCBs on MHR-SIR agar using two different inoculum protocols; (ii) the categorical agreement between dAST results obtained with MHR-SIR agar vs. those obtained with Muller-Hinton (MH) agar; and (iii) the ability of the MHR-SIR medium to detect β-lactam resistant Enterobacterales. Finally, we estimated the saved turnaround time (TAT) with MHR-SIR compared with MH agar in our 24/7 laboratory. Our results showed that the most suitable inoculation protocol for dAST on MHR-SIR agar was 1 drop of BCB/5 mL H2O. For monomicrobial Enterobacterales BCBs, dAST performed on MHR-SIR medium showed 99.3% categorical agreement with AST on MH agar. Furthermore, MHR-SIR agar allows early detection of β-lactam resistance mechanisms, including AmpC hyperproduction, extended-spectrum β-lactamase, and carbapenemase. Finally, TAT reduction in our 24/7 laboratory was 16 h, enabling a significantly faster provision of antibiotic advice.
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Affiliation(s)
- Mathilde Payen
- Laboratoire de Bactériologie, Hôpital L’Archet 2, Centre Hospitalier Universitaire de Nice, 06000 Nice, France; (M.P.); (A.G.); (J.K.); (A.E.); (G.M.); (R.L.)
- Institut National de la Santé et de la Recherche Médicale U1065, Centre Méditerranéen de Médecine Moléculaire, Équipe 6, 06200 Nice, France
- Faculté de Médecine, Université Côte d’Azur, 06200 Nice, France
| | - Alice Gaudart
- Laboratoire de Bactériologie, Hôpital L’Archet 2, Centre Hospitalier Universitaire de Nice, 06000 Nice, France; (M.P.); (A.G.); (J.K.); (A.E.); (G.M.); (R.L.)
| | - Kevin Legueult
- Département de Santé Publique, UR2CA, Université Côte d’Azur, Centre Hospitalier Universitaire de Nice, 06000 Nice, France; (K.L.); (C.P.)
| | - James Kasprzak
- Laboratoire de Bactériologie, Hôpital L’Archet 2, Centre Hospitalier Universitaire de Nice, 06000 Nice, France; (M.P.); (A.G.); (J.K.); (A.E.); (G.M.); (R.L.)
| | - Audrey Emery
- Laboratoire de Bactériologie, Hôpital L’Archet 2, Centre Hospitalier Universitaire de Nice, 06000 Nice, France; (M.P.); (A.G.); (J.K.); (A.E.); (G.M.); (R.L.)
| | - Grégoire Mutambayi
- Laboratoire de Bactériologie, Hôpital L’Archet 2, Centre Hospitalier Universitaire de Nice, 06000 Nice, France; (M.P.); (A.G.); (J.K.); (A.E.); (G.M.); (R.L.)
| | - Christian Pradier
- Département de Santé Publique, UR2CA, Université Côte d’Azur, Centre Hospitalier Universitaire de Nice, 06000 Nice, France; (K.L.); (C.P.)
| | - Frédéric Robin
- Laboratoire de Bactériologie Clinique, Institut National de la Santé et de la Recherche Médicale U1071, INRA USC2018, Centre Hospitalier Universitaire de Clermont-Ferrand, Université Clermont Auvergne, 63000 Clermont-Ferrand, France;
- Centre National de Référence de la Résistance aux Antibiotiques, Laboratoire Associé, 63000 Clermont-Ferrand, France
| | - Romain Lotte
- Laboratoire de Bactériologie, Hôpital L’Archet 2, Centre Hospitalier Universitaire de Nice, 06000 Nice, France; (M.P.); (A.G.); (J.K.); (A.E.); (G.M.); (R.L.)
- Institut National de la Santé et de la Recherche Médicale U1065, Centre Méditerranéen de Médecine Moléculaire, Équipe 6, 06200 Nice, France
- Faculté de Médecine, Université Côte d’Azur, 06200 Nice, France
| | - Raymond Ruimy
- Laboratoire de Bactériologie, Hôpital L’Archet 2, Centre Hospitalier Universitaire de Nice, 06000 Nice, France; (M.P.); (A.G.); (J.K.); (A.E.); (G.M.); (R.L.)
- Institut National de la Santé et de la Recherche Médicale U1065, Centre Méditerranéen de Médecine Moléculaire, Équipe 6, 06200 Nice, France
- Faculté de Médecine, Université Côte d’Azur, 06200 Nice, France
- Correspondence:
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5
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Performance Evaluation of the Quantamatrix QMAC-dRAST System for Rapid Antibiotic Susceptibility Testing Directly from Blood Cultures. Microorganisms 2022; 10:microorganisms10061212. [PMID: 35744730 PMCID: PMC9229829 DOI: 10.3390/microorganisms10061212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/10/2022] [Accepted: 06/12/2022] [Indexed: 02/01/2023] Open
Abstract
Objectives: Rapid antibiotic susceptibility testing (AST) for positive blood cultures can improve patient clinical outcomes if the time to an effective antimicrobial therapy is shortened. In this study, we tested the Quantamatrix dRAST system (QMAC-dRAST), a rapid AST system based on time-lapse microscopic imagery of bacterial colony formation in agarose. Methods: Evaluation of the QMAC-dRAST was performed from 250 monobacterial blood cultures including 130 Enterobacterales, 20 non-fermentative Gram-negative bacteria, 69 staphylococci and 31 enterococci. Blood cultures were recovered from anonymous patients or from spiking experiments to enrich our study with bacterial species and resistant strains. Categorical agreement (CA), minor errors (me), major errors (ME) and very major errors (VME) were calculated in comparison to the results obtained from the BD Phoenix™ M50. Discrepancies between the Phoenix™ M50 and QMAC-dRAST results were investigated using the gradient strip method. The repeatability and reproducibility performance of the QMAC-dRAST was assessed for 16 strains, each strain being tested five times from a spiked blood culture. Results: The overall CAs for Enterobacterales, non-fermentative Gram-negative bacteria, staphylococci and enterococci were 95.1%, 91.2%, 93.4% and 94.5%, respectively. The VME percentage was below 4% for all the groups except for staphylococci, which showed a VME rate of 7%. The median time to result was 6.7 h (range: 4.7–7.9). Repeatability and reproducibility assays showed a high reliability of AST results with best and worst ratios of 98.8% and 99.6% and 95.0% and 98.3%, respectively. Conclusions: The QMAC-dRAST is a fast and reliable system to determine AST directly from monobacterial blood cultures with a major TAT reduction compared to conventional AST testing.
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6
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Performance of dRAST on Prospective Clinical Blood Culture Samples in a Simulated Clinical Setting and on Multidrug-Resistant Bacteria. Microbiol Spectr 2022; 10:e0210721. [PMID: 35234503 PMCID: PMC8941874 DOI: 10.1128/spectrum.02107-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is an utmost need for rapid antimicrobial susceptibility testing (AST) of bacteria causing bloodstream infections (BSI). The dRAST (QuantaMatrix Inc., Seoul) is a commercial method that can be performed directly from positive blood cultures. The present study aims to evaluate the performance of the dRAST on prospective clinical blood culture samples. A sample prescreening algorithm based on clinical routine was used to choose relevant clinical positive blood culture samples for testing on the dRAST. Rapid identification via short-term culture followed by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) was used during the test run, and dRAST results were compared to European Committee on Antimicrobial Susceptibility Testing (EUCAST) disk diffusion as the reference method. The performance of the dRAST was also evaluated on selected multidrug resistant (MDR) isolates in simulated blood cultures. Using the sample pre-screening algorithm, 242 clinical blood culture samples were selected and tested on the dRAST, of which 200 (82.6%) gave valid AST tests results comprising 76 Gram-positive and 124 Gram-negative samples. AST measurements from the dRAST and disk diffusion from clinical samples had an overall agreement rate of 95.5%. When using simulated blood culture samples of 31 selected MDR isolates, the agreement between dRAST and disk diffusion was 87.2%. While the agreement rates were high, it was noted that the dRAST was not reliable for AST of certain antibiotic–bacteria combinations. In conclusion, the present study demonstrates that dRAST delivers rapid AST results from blood cultures and using a prescreening algorithm for sample selection is important in implementation of modern AST methods such as dRAST. IMPORTANCE There is an utmost need for rapid antimicrobial susceptibility testing (AST) of bacteria causing bloodstream infections (BSI). The dRAST (QuantaMatrix Inc., Seoul) is a rapid AST method that can be performed directly from positive blood cultures. The dRAST gives results in 6 h compared to conventional AST methods that needs 18-20 h of incubation. The present study aims to evaluate the performance of the dRAST in a clinical setting with the use of a sample selection algorithm to reduce incompatible sample numbers. The study found that while the agreement rates between dRAST and reference AST methods were high, it was noted that the dRAST was not reliable for AST of certain antibiotic–bacteria combinations. In conclusion, the present study demonstrates that dRAST delivers rapid AST results from blood cultures and using a prescreening algorithm for sample selection is important in implementation of modern AST methods such as dRAST.
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7
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Datar R, Orenga S, Pogorelcnik R, Rochas O, Simner PJ, van Belkum A. Recent Advances in Rapid Antimicrobial Susceptibility Testing. Clin Chem 2021; 68:91-98. [DOI: 10.1093/clinchem/hvab207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/17/2021] [Indexed: 12/30/2022]
Abstract
Abstract
Background
Antimicrobial susceptibility testing (AST) is classically performed using growth-based techniques that essentially require viable bacterial matter to become visible to the naked eye or a sophisticated densitometer.
Content
Technologies based on the measurement of bacterial density in suspension have evolved marginally in accuracy and rapidity over the 20th century, but assays expanded for new combinations of bacteria and antimicrobials have been automated, and made amenable to high-throughput turn-around. Over the past 25 years, elevated AST rapidity has been provided by nucleic acid-mediated amplification technologies, proteomic and other “omic” methodologies, and the use of next-generation sequencing. In rare cases, AST at the level of single-cell visualization was developed. This has not yet led to major changes in routine high-throughput clinical microbiological detection of antimicrobial resistance.
Summary
We here present a review of the new generation of methods and describe what is still urgently needed for their implementation in day-to-day management of the treatment of infectious diseases.
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Affiliation(s)
- Rucha Datar
- bioMérieux, Microbiology Research, La Balme Les Grottes, France
| | - Sylvain Orenga
- bioMérieux, Microbiology Research, La Balme Les Grottes, France
| | | | - Olivier Rochas
- bioMérieux, Corporate Business Development, Marcy l'Etoile, France
| | - Patricia J Simner
- Department of Pathology, Bacteriology, Division of Medical Microbiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Alex van Belkum
- bioMérieux, Open Innovation and Partnerships, La Balme Les Grottes, France
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8
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Anton-Vazquez V, Planche T. Gram-negative blood stream infections: prospects and challenges of rapid antimicrobial susceptibility testing. Expert Rev Anti Infect Ther 2021; 20:483-485. [PMID: 34706610 DOI: 10.1080/14787210.2022.1999805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Vanesa Anton-Vazquez
- Institute of Infection and Immunity, St. George's University of London, London, UK.,Department of Medical Microbiology, Southwest London Pathology, St. George's Hospital, London, UK.,Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Timothy Planche
- Institute of Infection and Immunity, St. George's University of London, London, UK.,Department of Medical Microbiology, Southwest London Pathology, St. George's Hospital, London, UK.,Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK
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Grohs P, Picard S, Mainardi JL, Podglajen I. Assessment of version 2.5 of QMAC-dRAST for rapid antimicrobial susceptibility testing with reduced sample-to-answer turnaround time and an integrated expert system. Infect Dis Now 2021; 51:470-476. [PMID: 34366083 DOI: 10.1016/j.idnow.2020.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/29/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To assess the performance of the new rapid antimicrobial susceptibility testing (AST) QMAC-dRAST V2.5 system. METHODS ASTs were performed using QMAC-dRAST-V2.5 and a disk diffusion method, directly from positive blood bottles with Gram-negative bacteria. Discrepancies between the results obtained using the two methods were categorized into very major errors (VME, S with dRAST vs. R with disk diffusion), major errors (ME, R vs. S, respectively), minor errors (mE, S vs. I or I vs. R, respectively), and very minor errors (Vme, I vs. S or R vs. I, respectively). For each AST, results were recorded after 4, 5, and 6h of incubation. RESULTS From 106 bacteremia, 1416 individual AST results were obtained. Overall agreement between results using the two methods was 91%, ranging from 76.9% to 99.1% depending upon the antibiotic, with 128 errors, i.e. 14/1416 (1%) VME, 59/1416 (4.2%) ME, 25/1416 (1.8%) mE and 30/1416 (2.1%) Vme. VMEs were encountered for Klebsiellasp and Serratia marcescens isolates with low-level piperacillin and amikacin resistance, respectively. Using the integrated QMAC-dRAST-V2.5 expert system, all 14 VMEs and 3 mEs were eliminated, leading to 92.2% categorical agreement. After 45min of pre-incubation in the QMAC-dRAST-V2.5 device, 22.2% of the 1416 AST results were obtained after 4h, an additional 31.4% after 5h and a further 46.3% after 6h. CONCLUSION QMAC-dRAST-V2.5 is an optimized version of QMAC-dRAST V2.0, particularly with respect to utilization of an expert system and reduced TAT according to the antibiotic tested.
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Affiliation(s)
- Patrick Grohs
- Microbiology department, Georges-Pompidou European Hospital, AP-HP, Centre - Université de Paris, Paris, France.
| | - Simon Picard
- Microbiology department, Georges-Pompidou European Hospital, AP-HP, Centre - Université de Paris, Paris, France
| | - Jean-Luc Mainardi
- Microbiology department, Georges-Pompidou European Hospital, AP-HP, Centre - Université de Paris, Paris, France
| | - Isabelle Podglajen
- Microbiology department, Georges-Pompidou European Hospital, AP-HP, Centre - Université de Paris, Paris, France
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10
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Christensen JJ, Junker H, Madsen CB, Christiansen CF, Kristensen T, Lund TK, Fallesen M, Kjølsen R, Hansen B, Hansen PK, Jensen US. Performance of QMAC-dRASTTM (Direct Rapid Antimicrobial Susceptibility Testing) - a Newcomer in Phenotypic Automatic AST. Open Microbiol J 2021. [DOI: 10.2174/1874285802115010043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Objective:
QMAC-dRASTTM is a phenotypic automatized Antibiotic Susceptibility Testing (AST) system based on microfluidic chip technology enabling observation of changes in a single bacterial cell under antibiotic treatment conditions. The 96 wells plate with dried antibiotics comprises 19 and 17 antibiotics for the Gram-Negatives (GNs) and Gram-Positives (GPs), respectively. Categorical (Sensitive, Intermediate or Resistant) results were compared to results obtained by our laboratory standard susceptibility testing procedure and given as Categorical Agreement (CA).
Methods:
In a 3-month period (2019/2020), blood cultures detected positive were included. Excluded were known off-panel strains of QMAC-dRASTTM, such as Gram-positive bacilli, Streptococcus and Candida species. Percentages of CA (CA, %) between QMAC-dRASTTM and routine testing methods used in the laboratory (EUCAST disc diffusion and/or etest/Broth Micro Dilution MIC), were calculated.
Results:
255 positive blood cultures from as many patients were examined. Of the positive blood culture strains, 144 were GNs, and 111 were GPs. An overall combined CA,% of 96.3 (2410 of 2502 determinations) was obtained, and discrepancies were noted in 92 of 2502 test results (3.7%). The percentage of very major errors (VMEs) was 0.7% for GNs and 2.2% for GPs. For 87% of blood culture specimens examined, susceptibility reports were available within 6-7 hours.
Conclusion:
The high CA,% for as well GNs as GPs are promising. The presented time to report data obtained by QMAC-dRASTTM in this study being of 3-8 hours for blood culture specimens examined strongly support a further possible improvement in the workflow for handling blood stream infections.
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11
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Banerjee R, Humphries R. Rapid Antimicrobial Susceptibility Testing Methods for Blood Cultures and Their Clinical Impact. Front Med (Lausanne) 2021; 8:635831. [PMID: 33777978 PMCID: PMC7987685 DOI: 10.3389/fmed.2021.635831] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/01/2021] [Indexed: 12/29/2022] Open
Abstract
Antimicrobial susceptibility testing (AST) of bacteria isolated in blood cultures is critical for optimal management of patients with sepsis. This review describes new and emerging phenotypic and genotypic AST methods and summarizes the evidence that implementation of these methods can impact clinical outcomes of patients with bloodstream infections.
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Affiliation(s)
- Ritu Banerjee
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Romney Humphries
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States
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