Evaluation of blood culture media for the detection of fungi

Nawrot, Urszula; Kowalska−Krochmal, Beata; Sulik-Tyszka, Beata; Kozák, Milan; Świętek, K.; Pajączkowska, Magdalena; Piątkowska, Elżbieta; Rosiak, D.; Swoboda-Kopeć, Ewa

doi:10.1007/s10096-014-2218-4

Cited by 37 publications

(23 citation statements)

References 20 publications

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“…There was a pronounced delay in detecting growth of Candida glabrata by the automated system using an aerobic bottle, which occurred at the 1 CFU/ml concentration 26.6 h after the successful identification of the species from directly inoculated chocolate agar ( Table 1). The delayed detection of C. glabrata using a Bactec Plus aerobic/F bottle was previously reported (5,12). Using a score of Ն1.7 as a criterion for successful identification on a species level (13) provided reliable results without misidentifications compared to those from internal transcribed spacer (ITS) sequencing.…”

Section: Resultsmentioning

confidence: 92%

Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)

2017

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Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption-ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems.KEYWORDS Candida, candidemia, MALDI-TOF, blood culture, direct blood culturing, lysis-centrifugation, mass spectrometry, rapid tests, sepsis C andidemia is associated with a particularly high mortality rate that is increasing, especially among immunocompromised and critically ill patients (1-3). While early and appropriate treatment is vital (3), the slow growth of yeasts delays a timely diagnosis (4). The current diagnostic standard includes inoculation of the patient's blood into special bottles with liquid medium and incubation in an automated blood culture (BC) instrument (5). In cases where growth is detected, Gram staining is performed and the broth is subcultivated onto a solid medium to grow colonies for identification and antimicrobial susceptibility testing (AST) (4). The lysis-centrifugation blood culture (LC BC) method is an alternative approach, which has been available for decades but whose use has declined with the advent of blood culture automation (6-9). LC BC involves the selective lysis of blood cells with subsequent centrifugation and culturing of the sediment directly on agar plates (6). A recent study found that this approach provides a dramatic reduction in the time required for BC diagnostics of bacteria when combined with the modern methods of identification and susceptibility testing (10).In this study, we investigated whether the direct cultivation on solid medium using the LC BC method combined with identification by matrix-assisted laser desorptionionization time of flight mass spectrometry (MALDI-TOF MS) would result in a more rapid detection and differentiation of yeasts from blood compared to that with the currently used liquid medium-based automated BC instruments. We also investigated the impact of specific fungal or general media used with each method.

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Section: Resultsmentioning

confidence: 92%

Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)

2017

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“…This initial growth-based amplification ensures sensitive detection but extends the diagnostic timeline such that test results do not effectively impact patient management. It also restricts the breadth of organisms detected by relying on a single culture medium formulation, which cannot support the growth of all organisms or may mask susceptibilities (84)(85)(86)(87). While molecular diagnostic tests are completed within 20 min to 2 h, the initial step of blood culture takes several hours to days and may not be successful.…”

Section: Towards Detection Directly From Whole Blood: Current and Emementioning

confidence: 99%

Emerging Technologies for Molecular Diagnosis of Sepsis

et al. 2018

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Rapid and accurate profiling of infection-causing pathogens remains a significant challenge in modern health care. Despite advances in molecular diagnostic techniques, blood culture analysis remains the gold standard for diagnosing sepsis. However, this method is too slow and cumbersome to significantly influence the initial management of patients. The swift initiation of precise and targeted antibiotic therapies depends on the ability of a sepsis diagnostic test to capture clinically relevant organisms along with antimicrobial resistance within 1 to 3 h. The administration of appropriate, narrow-spectrum antibiotics demands that such a test be extremely sensitive with a high negative predictive value. In addition, it should utilize small sample volumes and detect polymicrobial infections and contaminants. All of this must be accomplished with a platform that is easily integrated into the clinical workflow. In this review, we outline the limitations of routine blood culture testing and discuss how emerging sepsis technologies are converging on the characteristics of the ideal sepsis diagnostic test. We include seven molecular technologies that have been validated on clinical blood specimens or mock samples using human blood. In addition, we discuss advances in machine learning technologies that use electronic medical record data to provide contextual evaluation support for clinical decision-making.

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“…Fungemia cases are being caused mainly by Candida species, which are the fourth most common microorganisms isolated from the blood samples (3,4,5). Sepsis due to Candida spp.…”

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confidence: 99%

Evaluation of Fluorescent Capillary Electrophoresis for Rapid Identification of Candida Fungal Infections

et al. 2016

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dEarly diagnosis of fungal infection is critical for initiating antifungal therapy and reducing the high mortality rate in immunocompromised patients. In this study, we focused on rapid and sensitive identification of clinically important Candida species, utilizing the variability in the length of the ITS2 rRNA gene and fluorescent capillary electrophoresis (f-ITS2-PCR-CE). The method was developed and optimized on 29 various Candida reference strains from which 26 Candida species were clearly identified, while Candida guilliermondii, C. fermentati, and C. carpophila, which are closely related, could not be distinguished. The method was subsequently validated on 143 blinded monofungal clinical isolates (comprising 26 species) and was able to identify 88% of species unambiguously. This indicated a higher resolution power than the classical phenotypic approach which correctly identified 73%. Finally, the culture-independent potential of this technique was addressed by the analysis of 55 retrospective DNA samples extracted directly from clinical material. The method showed 100% sensitivity and specificity compared to those of the combined results of cultivation and panfungal PCR followed by sequencing used as a gold standard. In conclusion, this newly developed f-ITS2-PCR-CE analytical approach was shown to be a fast, sensitive, and highly reproducible tool for both culture-dependent and culture-independent identification of clinically important Candida strains, including species of the "psilosis" complex. During the last several decades, the impact and frequency of fungal infections have gained importance mainly due to an increasing number of immunocompromised patients (1, 2). Fungemia cases are being caused mainly by Candida species, which are the fourth most common microorganisms isolated from the blood samples (3, 4, 5). Sepsis due to Candida spp. is a very serious condition and has a higher mortality rate that for bacterial pathogens; reaching 54 to 64% in Candida-associated septic shock (6, 7). Moreover, the current changes in the epidemiology of invasive mycoses has highlighted a shift in the Candida species involved with a reduced proportion of Candida albicans and an increase in non-albicans species, which can show different susceptibility to various antifungal therapies (8,9,10).Early initiation of antifungal therapy is a critical step in the treatment of fungal infections. Therefore, quick, successful detection and identification of the etiological agents is crucial for early targeted therapy and favorable clinical patient outcome (11). Correct species identification is mostly based on phenotypic features and is usually time-consuming because a typical diagnostic workflow takes up to several days. Moreover, the phenotypic methods may lead to misidentification, particularly in the case of closely related species (12, 13). A significant improvement occurred when matrix-assisted laser desorption ionizationϪtime of flight mass spectroscopy (MALDI-TOF MS) was introduced as a routine laboratory procedure, enab...

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Evaluation of blood culture media for the detection of fungi

Cited by 37 publications

References 20 publications

Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)

Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)

Emerging Technologies for Molecular Diagnosis of Sepsis

Evaluation of Fluorescent Capillary Electrophoresis for Rapid Identification of Candida Fungal Infections

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