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New Antifungal Susceptibility Test Based on Chitin Detection by Image Cytometry. Antimicrob Agents Chemother 2019; 64:AAC.01101-19. [PMID: 31658964 DOI: 10.1128/aac.01101-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 10/11/2019] [Indexed: 12/16/2022] Open
Abstract
The antifungal susceptibility tests used in clinical laboratories have several limitations. We developed a new test, SensiFONG, based on the detection of chitin levels after exposure to antifungal drugs. The optimal culture conditions were 30°C for 6 h for yeast strains and 26°C for 16 h for molds. The strains were exposed to a range of echinocandin or azole concentrations. Chitin was stained with calcofluor white. The percentage of fungal cells with high chitin levels was determined with an automatic epifluorescence microscope. The SensiFONG results were compared to those with the EUCAST method. Image acquisition and analysis were performed with ScanR software. Fifty-nine strains (28 Candida albicans, 17 Candida glabrata, and 14 Aspergillus fumigatus) were analyzed. Thresholds for the classification of strains as resistant or susceptible were determined for each fungal species. The strains displaying an increase in chitin content of ≥32% for C. albicans, ≥6% for C. glabrata, and ≥17% for A. fumigatus were considered susceptible. The application of these thresholds to all 59 strains resulted in a sensitivity of 0.87, 0.93, and 1.00 and a specificity of 0.93, 0.84, and 0.82 for C. albicans, C. glabrata, and A. fumigatus, respectively. The correlation between the results obtained in the SensiFONG and EUCAST assays was excellent. We developed a new test, SensiFONG, based on a new concept. While current assays assess growth inhibition, our test detects changes in chitin levels after exposure to antifungal drugs. Here, we present preliminary results and we propose a proof of concept of this methodology.
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Muñoz P, Vena A, Machado M, Martínez-Jiménez MC, Gioia F, Gómez E, Origüen J, Orellana MÁ, López-Medrano F, Pérez-Granda MJ, Aguado JM, Fortún J, Bouza E. T2MR contributes to the very early diagnosis of complicated candidaemia. A prospective study. J Antimicrob Chemother 2019; 73:iv13-iv19. [PMID: 29608752 DOI: 10.1093/jac/dky048] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Objectives Diagnosis of complicated candidaemia represents a challenge for clinicians since early clinical manifestations may be non-specific and difficult to identify, thus precluding an appropriate treatment. Patients and methods This was a multicentre prospective study for predicting complicated episodes in patients with bloodstream infection caused by Candida species, while assessing the value of follow-up blood cultures (BCs) and the persistence of positive results for T2Candida MR (T2MR) and blood β-d-glucan (BDG) tests. Immediately after the first positive BC yielding Candida species, samples were obtained on days 0, +2, +4, +7 and +14, to simultaneously perform follow-up BC, T2MR and BDG. An episode of candidaemia was defined as 'complicated' when (i) it caused septic metastasis; and/or (ii) it was the cause of the patient's death. Results From January to June 2017, 30 patients were enrolled in the study. Of these, nine (30%) had complicated candidaemia. Values of persistently positive samples for the prediction of complicated episodes for BCs, T2MR and BDG, respectively, were as follows: sensitivity (44.4%, 100%, 100%); specificity (76.1%, 76.1%, 38.9%); positive predictive value (PPV) (44.4%, 64.2%, 40.9%) and negative predictive value (NPV) (76.1%, 100%, 100%). In multivariate analysis, having a positive T2MR within the first 5 days was associated with an almost 37-fold higher risk of developing complicated candidaemia. Conclusions The T2MR test performed in patients with proven candidaemia may be a better marker of complicated infection than follow-up BCs or BDG. It is possible that this test may change current clinical practice, influencing the length and type of antifungal therapy in this population.
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Affiliation(s)
- Patricia Muñoz
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain.,CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain.,Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
| | - Antonio Vena
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain.,Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain.,Infectious Diseases Clinic, Department of Medicine, University of Udine and Azienda Sanitaria Universitaria Integrata, Udine, Italy
| | - Marina Machado
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain.,Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
| | | | - Francesca Gioia
- Infectious Diseases Department, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Elia Gómez
- Infectious Diseases Department, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Julia Origüen
- Unit of Infectious Diseases, Hospital Universitario '12 de Octubre', Instituto de Investigación Hospital '12 de Octubre' imas12, Universidad Complutense, Madrid, Spain
| | - María Ángeles Orellana
- Unit of Infectious Diseases, Hospital Universitario '12 de Octubre', Instituto de Investigación Hospital '12 de Octubre' imas12, Universidad Complutense, Madrid, Spain
| | - Francisco López-Medrano
- Unit of Infectious Diseases, Hospital Universitario '12 de Octubre', Instituto de Investigación Hospital '12 de Octubre' imas12, Universidad Complutense, Madrid, Spain
| | - María-Jesús Pérez-Granda
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - José María Aguado
- Unit of Infectious Diseases, Hospital Universitario '12 de Octubre', Instituto de Investigación Hospital '12 de Octubre' imas12, Universidad Complutense, Madrid, Spain
| | - Jesús Fortún
- Infectious Diseases Department, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Emilio Bouza
- Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Hospital Gregorio Marañón, Madrid, Spain.,CIBER Enfermedades Respiratorias-CIBERES (CB06/06/0058), Madrid, Spain.,Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain
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In Vitro Evaluation of BacT/Alert FA Blood Culture Bottles and T2Candida Assay for Detection of Candida in the Presence of Antifungals. J Clin Microbiol 2018; 56:JCM.00471-18. [PMID: 29898999 DOI: 10.1128/jcm.00471-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/06/2018] [Indexed: 11/20/2022] Open
Abstract
The T2Candida assay is a novel, non-culture-based assay for the diagnosis of candidemia directly from whole blood. The impact of antifungals on the performance of the T2Candida assay and blood culture bottles has not been well described. In this study, the performance of the T2Candida assay was compared to that of blood culture in detecting Candida spp. in spiked blood cultures with or without the presence of antifungals. Clinical bloodstream isolates of Candida spp. were inoculated into human whole blood at low (1 to 5 cells/ml) and high (10 to 50 cells/ml) concentrations with or without the presence of caspofungin and fluconazole. Time to detection (TTD) was assessed for prepared samples using BacT/Alert FA aerobic blood culture bottles or the T2Candida assay. In the absence of antifungals, T2Candida assay sensitivity was comparable to that of blood culture at both the low inoculum and the high inoculum (95% versus 97.5% and 100% versus 100%, respectively) and the assay had an average TTD that was significantly shorter (5.1 h versus 27.2 to 30 h, respectively). Neither caspofungin nor fluconazole was observed to impact the sensitivity or TTD of the T2Candida assay, while fluconazole reduced the overall blood culture sensitivity by 7.5% to 12.5% (at the low inoculum and high inoculum, respectively) and significantly increased the TTD of Candida albicans, C. tropicalis, and C. parapsilosis by 14.8 to 67 h. Neither caspofungin nor fluconazole impacted the performance of the T2Candida assay in vitro, and the assay may be useful for the diagnosis of candidemia in patients receiving antifungal therapy.
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Maubon D, Dard C, Garnaud C, Cornet M. Profile of GenMark's ePlex® blood culture identification fungal pathogen panel. Expert Rev Mol Diagn 2017; 18:119-132. [PMID: 29284316 DOI: 10.1080/14737159.2018.1420476] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Fungemia presents high morbi-mortality and thus rapid microbiological diagnosis may contribute to appropriate patient management. In the last decade, kits based on molecular technologies have become available and health care institutes are increasingly facing critical investment choices. Although all these tools aim to achieve rapid fungal detection and species identification, they display different inherent characteristics. Areas covered: Considering technologies allowing detection and identification of fungal species in a sepsis context, the market proposes either tests on positive blood culture or tests on patient's whole blood. In this review, the authors describe and compare the ePlex® Blood Culture Identification Fungal Pathogen (BCID-FP) test, a fully automated one-step single-use cartridge assay that has been designed to detect identify frequent or rare but emerging, fungal species, from positive blood culture. A comparison with the competing kits is provided. Expert commentaries: The ePlex BCID-FP test provides a diversified and rather relevant panel. Its easy-to-use cartridges allow flexible use around the clock. Nevertheless, prospective clinical studies assessing the time-to-result benefit on antifungal stewardship and on hospital length of stay are not available yet. New tools aim to benefit clinicians and patients, but they should be accompanied by supervision of result interpretation and adaptation of antifungal stewardship.
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Affiliation(s)
- Danièle Maubon
- a Univsité Grenoble Alpes, CNRS, Grenoble INP*, TIMC-IMAG , Grenoble , France.,b Parasitology-Mycology Laboratory, Infectious Agents Department , CHU Grenoble-Alpes , Grenoble , France
| | - Céline Dard
- b Parasitology-Mycology Laboratory, Infectious Agents Department , CHU Grenoble-Alpes , Grenoble , France
| | - Cécile Garnaud
- a Univsité Grenoble Alpes, CNRS, Grenoble INP*, TIMC-IMAG , Grenoble , France.,b Parasitology-Mycology Laboratory, Infectious Agents Department , CHU Grenoble-Alpes , Grenoble , France
| | - Muriel Cornet
- a Univsité Grenoble Alpes, CNRS, Grenoble INP*, TIMC-IMAG , Grenoble , France.,b Parasitology-Mycology Laboratory, Infectious Agents Department , CHU Grenoble-Alpes , Grenoble , France
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