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Morecchiato F, Coppi M, Chilleri C, Antonelli A, Giani T, Rossolini GM. Evaluation of Quantamatrix dRAST TM system for rapid antimicrobial susceptibility testing of bacterial isolates from positive blood cultures, in comparison with commercial Micronaut broth microdilution system. Diagn Microbiol Infect Dis 2024; 110:116436. [PMID: 39003931 DOI: 10.1016/j.diagmicrobio.2024.116436] [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: 05/08/2024] [Revised: 07/10/2024] [Accepted: 07/10/2024] [Indexed: 07/16/2024]
Abstract
Antimicrobial susceptibility testing (AST) from blood culture (BC) may take several days, limiting the eventual impact on antimicrobial stewardship. Hence, rapid AST systems represent a valuable support in shorting the time-to-response. In this work, the Quantamatrix dRASTTM system (dRAST) was evaluated for rapid AST on 100 monomicrobial BCs (50 Gram-negatives and 50 Gram-positives), including several isolates with clinically relevant resistance mechanisms. AST results were provided in 6-hours, on average. Compared to Micronaut (Merlin) system based on broth microdilution, dRAST exhibited an overall categorical agreement of 92.5 %, essential agreement of 89.0 %, and mean bias of 15.9 %. Category overestimation (potentially leading to unnecessary high-dosage treatment or to exclude active agents) and category underestimation (potentially leading to underdosing or using ineffective agents) were observed in 4.3 % and 3.1 % of cases, respectively. Even though several issues were reported, results confirmed the potential contribution of dRAST to shorten the BCs clinical microbiology workflow and management.
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Affiliation(s)
- Fabio Morecchiato
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Marco Coppi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Microbiology and Virology Unit, Careggi University Hospital, Florence, Italy
| | - Chiara Chilleri
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Microbiology and Virology Unit, Careggi University Hospital, Florence, Italy
| | - Alberto Antonelli
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Microbiology and Virology Unit, Careggi University Hospital, Florence, Italy
| | - Tommaso Giani
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Microbiology and Virology Unit, Careggi University Hospital, Florence, Italy
| | - Gian Maria Rossolini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Microbiology and Virology Unit, Careggi University Hospital, Florence, Italy.
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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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Esse J, Träger J, Valenza G, Bogdan C, Held J. Rapid phenotypic antimicrobial susceptibility testing of Gram-negative rods directly from positive blood cultures using the novel Q-linea ASTar system. J Clin Microbiol 2023; 61:e0054923. [PMID: 37819072 PMCID: PMC10662367 DOI: 10.1128/jcm.00549-23] [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: 04/28/2023] [Accepted: 08/19/2023] [Indexed: 10/13/2023] Open
Abstract
Adequate and timely antibiotic therapy is crucial for the treatment of sepsis. Innovative systems, like the Q-linea ASTar, have been developed to perform rapid antimicrobial susceptibility testing (AST) directly from positive blood cultures (BCs). We conducted a prospective study to evaluate ASTar under real-life conditions with a focus on time-to-result and impact on antimicrobial therapy. Over 2 months, all positive BCs that showed Gram-negative rods upon microscopy were tested with the ASTar and our standard procedure (VITEK 2 from short-term culture). Additionally, we included multidrug-resistant Gram-negative bacteria from our archive. Both methods were compared to broth microdilution. In total, 78 bacterial strains (51 prospective and 27 archived) were tested. ASTar covered 94% of the species encountered. The categorical and essential agreement was 95.6% and 90.7%, respectively. ASTar caused 2.4% minor, 2.0% major, and 2.4% very major errors. The categorical agreement was similar to standard procedure. The average time between BC sampling and the availability of the antibiogram for the attending physician was 28 h 49 min for ASTar and 44 h 18 min for standard procedure. ASTar correctly identified all patients who required an escalation of antimicrobial therapy and 75% of those who were eligible for de-escalation. In conclusion, ASTar provided reliable AST results and significantly shortened the time to obtain an antibiogram. However, the percentage of patients that will profit from ASTar in a low-resistance setting is limited, and it is currently unclear if a change of therapy 29 h after BC sampling will have a significant impact on the patient's prognosis.
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Affiliation(s)
- Jan Esse
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene - Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Johannes Träger
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene - Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Giuseppe Valenza
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene - Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Christian Bogdan
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene - Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Jürgen Held
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene - Universitätsklinikum Erlangen and Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
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Kalın G, Alp E, Chouaikhi A, Roger C. Antimicrobial Multidrug Resistance: Clinical Implications for Infection Management in Critically Ill Patients. Microorganisms 2023; 11:2575. [PMID: 37894233 PMCID: PMC10609422 DOI: 10.3390/microorganisms11102575] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/05/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
The increasing incidence of antimicrobial resistance (AMR) worldwide represents a serious threat in the management of sepsis. Due to resistance to the most common antimicrobials prescribed, multidrug-resistant (MDR) pathogens have been associated with delays in adequate antimicrobial therapy leading to significant increases in mortality, along with prolonged hospital length of stay (LOS) and increases in healthcare costs. In response to MDR infections and the delay of microbiological results, broad-spectrum antibiotics are frequently used in empirical antimicrobial therapy. This can contribute to the overuse and misuse of antibiotics, further promoting the development of resistance. Multiple measures have been suggested to combat AMR. This review will focus on describing the epidemiology and trends concerning MDR pathogens. Additionally, it will explore the crucial aspects of identifying patients susceptible to MDR infections and optimizing antimicrobial drug dosing, which are both pivotal considerations in the fight against AMR. Expert commentary: The increasing AMR in ICUs worldwide makes the empirical antibiotic therapy challenging in septic patients. An AMR surveillance program together with improvements in MDR identification based on patient risk stratification and molecular rapid diagnostic tools may further help tailoring antimicrobial therapies and avoid unnecessary broad-spectrum antibiotics. Continuous infusions of antibiotics, therapeutic drug monitoring (TDM)-based dosing regimens and combination therapy may contribute to optimizing antimicrobial therapy and limiting the emergence of resistance.
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Affiliation(s)
- Gamze Kalın
- Department of Infectious Diseases and Clinical Microbiology, Faculty of Medicine, Erciyes University, Kayseri 38280, Türkiye
| | - Emine Alp
- Department of Infectious Diseases and Clinical Microbiology, Faculty of Medicine, Ankara Yıldırım Beyazıt University, Ankara 06760, Türkiye;
| | - Arthur Chouaikhi
- Department of Anesthesiology and Intensive Care, Pain and Emergency Medicine, Nîmes-Caremeau University Hospital, Place du Professeur Robert Debré, CEDEX 9, 30029 Nîmes, France;
| | - Claire Roger
- Department of Anesthesiology and Intensive Care, Pain and Emergency Medicine, Nîmes-Caremeau University Hospital, Place du Professeur Robert Debré, CEDEX 9, 30029 Nîmes, France;
- UR UM 103 IMAGINE, Faculty of Medicine, Montpellier University, Chemin du Carreau de Lanes, 30029 Nîmes, France
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Kim KJ, Yun SG, Cho Y, Nam MH, Ko YJ, Lee CK. Evaluation of a sterile, filter-based, in-house method for rapid direct bacterial identification and antimicrobial susceptibility testing using positive blood culture. Eur J Clin Microbiol Infect Dis 2023; 42:691-700. [PMID: 37012540 DOI: 10.1007/s10096-023-04592-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/24/2023] [Indexed: 04/05/2023]
Abstract
This study aimed to assess the performance of our in-house method for rapid direct bacterial identification (ID) and antimicrobial susceptibility testing (AST) using a positive blood culture (BC) broth. For Gram-negative bacteria, 4 mL of BC broth was aspirated and passed through a Sartorius Minisart syringe filter with a pore size of 5 µm. The filtrate was then centrifuged and washed. A small volume of the pellet was used for ID, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and for AST, using automated broth microdilution. For Gram-positive cocci, 4 mL of BC broth was passed through the Minisart syringe filter. Then, 4 mL of sterile distilled water was injected in the direction opposite to that of the filtration to collect the bacterial residue trapped in the filter. Compared with the conventional method performed with pure colonies on agar plates, 94.0% (234/249) were correctly identified using the in-house method, with rates of 91.4% (127/139) and 97.3% (107/110) for Gram-positive and Gram-negative isolates, respectively. Of 234 correctly identified isolates, 230 were assessed by AST. Categorical agreement and essential agreement were 93.3% and 94.5%, respectively, with a minor error rate of 3.8%, a major error rate of 3.4%, and a very major error rate of 1.6%. Our in-house preparation method showed good performance in rapid direct ID and AST using positive BC broths compared to the conventional method. This simple method can shorten the conventional turnaround time for ID and AST by at least 1 day, potentially contributing to better patient management.
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Affiliation(s)
- Keun Ju Kim
- Department of Laboratory Medicine, College of Medicine, Korea University, Seoul, Korea
| | - Seung Gyu Yun
- Department of Laboratory Medicine, College of Medicine, Korea University, Seoul, Korea
| | - Yunjung Cho
- Department of Laboratory Medicine, College of Medicine, Korea University, Seoul, Korea
| | - Myung-Hyun Nam
- Department of Laboratory Medicine, College of Medicine, Korea University, Seoul, Korea
| | - Young Jin Ko
- Department of Laboratory Medicine, College of Medicine, Chosun University, Gwangju, Korea
| | - Chang Kyu Lee
- Department of Laboratory Medicine, College of Medicine, Korea University, Seoul, Korea.
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Fully Automated EUCAST Rapid Antimicrobial Susceptibility Testing (RAST) from Positive Blood Cultures: Diagnostic Accuracy and Implementation. J Clin Microbiol 2022; 60:e0089822. [PMID: 36173195 DOI: 10.1128/jcm.00898-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The objective of this study was to evaluate the accuracy and robustness of a fully automated EUCAST RAST (rapid antimicrobial susceptibility test) directly from positive blood culture and to appreciate its implementation constraints. This study was conducted in two phases: (i) spiked blood culture bottles (BCs) using 779 non-duplicate clinical isolates and (ii) a prospective clinical trial including 534 positive BCs sequentially processed in routine at the Bacteriology Laboratory of Geneva University Hospitals. The RAST results were assessed against EUCAST standardized disk diffusion testing results. Our first finding was that the results of the spiked BCs precisely predicted the clinical trial results. The overall categorical agreements for all species analyzed were greater than 95% at the different time points. RAST for Pseudomonas aeruginosa, however, raised several challenges. The categorical agreement for imipenem was lower than 95% at 6 h and was not improved with longer incubation times. Additionally, piperacillin-tazobactam, ceftazidime, and cefepime cannot be released at 6 h due to suboptimal performances, but the categorical agreement substantially improved at 8 h. Our results establish that the performance of fully automated EUCAST RAST directly from positive blood culture bottles is consistently robust, even for the detection of extended-spectrum β-lactamase (ESBL), carbapenemase-producing bacteria, and methicillin-resistant Staphylococcus aureus (MRSA). The automation markedly enhanced the percentage of readable inhibition zones and reduced the percentage of isolates categorized in the area of technical uncertainty (ATU). In summary, a fully automated EUCAST RAST can substantially improve laboratory workflow by reducing hands-on time and removing the strong constraints linked to manual read-outs at precisely defined times.
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