Evaluación de una nueva técnica comercializada (Candida albicans IFA IgG) para el diagnóstico de la candidiasis invasiva

doi:10.1016/S0213-005X(04)73039-6

Enfermedades Infecciosas y Microbiología Clínica

Volume 22, Issue 2, 2004, Pages 83-88

https://doi.org/10.1016/S0213-005X(04)73039-6 Get rights and content

Introducción

Se comparan dos pruebas para detectar anticuerpos antimicelio en pacientes con candidiasis invasiva: una nueva técnica comercializada (Candida albicans IFA IgG) y la técnica de inmunofluorescencia indirecta tradicionalmente empleada para la detección de anticuerpos contra la fase micelial de C. albicans (anticuerpos antimicelio)

Métodos

Mediante dos técnicas de inmunofluorescencia indirecta se estudiaron retrospectivamente un total de 172 sueros de 51 pacientes clasificados en dos grupos: el grupo I incluía 123 sueros de 32 pacientes con candidiasis invasiva y el grupo II, utilizado como control, comprendía 49 sueros de 19 pacientes sin evidencia de infección por Candida

Resultados

El 84,4% de los pacientes con candidiasis invasiva (grupo I) presentaron títulos de anticuerpos antimicelio ≥ 1:160 con la prueba Candida albicans IFA IgG, mientras que el 78,1% lo hicieron con la técnica tradicional. Ambas técnicas presentaron una alta correlación al ser comparadas entre sí (R²= 0,9512 por pacientes; R²= 0,8986 por sueros). Utilizando un título de corte de anticuerpos antimicelio ≥ 1:160 para el diagnóstico de la candidiasis invasiva, la prueba Candida albicans IFA IgG presentó una sensibilidad del 84,4% y una especificidad del 94,7%, mientras que la técnica tradicional presentó una sensibilidad del 78,1% y una especificidad del 100%. Conclusión. La prueba comercializada Candida albicans IFA IgG es muy similar a la prueba tradicionalmente empleada para la detección de anticuerpos antimicelio, permitiendo un diagnóstico más rápido y sencillo de la candidiasis invasiva en los laboratorios de microbiología hospitalarios

Introduction

Two tests for the detection of antibodies to Candida albicans germ tubes in patients with invasive candidiasis were compared: a new commercially available test (Candida albicans IFA IgG) and the indirect immunofluorescence test generally used for this purpose

Methods

With the use of two indirect immunofluorescence tests, retrospective study was done on 172 sera from 51 patients classified into two groups: Group I included 123 serum samples from 32 patients with invasive candidiasis, and Group II, the control, included 49 serum samples from 19 patients with no evidence of Candida infection

Results

In Group I, 84% of patients presented anti-germ tube antibody titers ≥ 1:160 by the Candida albicans IFA IgG test and 78.1% of patients were positive by the generally used test. There was a high correlation between the two tests (R²= 0.9512 by patients; R²= 0.8986 by sera). When a titer value of ≥ 1:160 was used as cutoff, the Candida albicans IFA IgG test showed a sensitivity of 84.4% and a specificity of 94.7%, whereas the traditional test showed a sensitivity of 78.1% and a specificity of 100%. Conclusions. The commercially available Candida albicans IFA IgG test is similar to the test generally used for the detection of antibodies to C. albicans germ tubes and provides faster and easier diagnosis of invasive candidiasis in the clinical microbiology laboratory

Bibliografía (23)

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Infecciones fúngicas invasivas en pacientes con hemopatías malignas: una aproximación clínica
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Detection of antibodies to Candida albicans germ tubes for the diagnosis and therapeutic monitoring of invasive candidiasis in patients with hematologic malignancies

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Cited by (53)

Biomarkers for the diagnosis of invasive candidiasis in immunocompetent and immunocompromised patients
2021, Diagnostic Microbiology and Infectious Disease
Citation Excerpt :
Importantly, CAGTA specificity was high (89%−100%) but, even raising the cut-off to 1/80, as recommended by Martínez-Jiménez et al. (2015), the sensitivity did not exceed 61% in immunocompetent patients, and these values agree with the recently reported data of Pini et al. (2019). Previous studies of our group claimed higher sensitivity values (García-Ruiz et al., 1997, Moragues et al., 2004), and Trovato et al. (2020) reported 91.3% sensitivity in long-stay ICU patients, emphasizing the value of serial monitoring to assess the kinetics of CAGTA for the clinical diagnosis of IC. Moreover, the occurrence of CAGTA has been associated with a lower mortality rate of ICU patients receiving antifungal treatment (Zaragoza et al., 2009).
Blood culture methods show low sensitivity, so reliable non–culture diagnostic tests are needed to help clinicians with the introduction, de-escalation, and discontinuation of antifungal therapy in patients with suspected invasive candidiasis (IC). We evaluated different biomarkers for the diagnosis of IC in immunocompetent and immunocompromised patients at risk for developing invasive fungal diseases. The specificity of Candida albicans germ-tube antibodies (CAGTA) detection was high (89%−100%), but sensitivity did not exceed 61% even after raising the cut-off from 1/160 to 1/80. We developed enzyme-linked immunoassays detecting antibodies against C. albicans proteins (Als3-N, Hwp1-N, or Met6) that resulted more sensitive (66%−92%) but less specific than CAGTA assay. The combination of 1,3-beta-D-glucan (BDG) detection and CAGTA results provided the highest diagnostic usefulness in immunocompetent patients. However, in immunocompromised patients, anti–Met6 antibodies was the best biomarker, both, alone or in combination with BDG.
Diagnostic surveillance by Candida albicans germ tube antibody in intensive care unit patients
2020, Journal of Microbiology, Immunology and Infection
Citation Excerpt :
For proven/probable IC the CAGTA technique had sensitivity, specificity, PPV and NPV of 91.3%, 68.1%, 58.3% and 94.1%, respectively. Compared to prior studies,12,13 overall CAGTA assay sensitivity was slightly higher in our cohort, while the specificity was lower, probably because in our study 15 patients without IC had titers ≥1/160. However, 78.6% (11/15) of these patients had titers ≥1/160 at the enrolment time in the study, although they did not develop proven/probable IC during monitoring.
The diagnosis of Invasive Candidiasis (IC) presents serious problems, mainly associated with the absence of pathognomonic symptoms of the disease and the difficulty of isolating the fungus in blood culture. Candida albicans germ tube antibody (CAGTA) provides a rapid and simple test for diagnosis of IC. The aim of this study was to evaluate the diagnostic role of the CAGTA in the monitoring of critically-ill patients at risk of developing IC.
During diagnostic surveillance in the intensive care units (ICU) CAGTA was performed twice a week if predetermined risk factors were present and a positive result was considered when a serum titer ≥1/160 was detected in at least one sample.
Seventy critically ill patients were included in the study. Twenty-three patients with proven/probable IC were identified. The sensitivity, specificity, PPV, and NPV of CAGTA for the diagnosis of proven/probable IC in all 70 patients were 91.3%, 68.1%, 58.3%, and 94.1%, respectively. Statistically significant highest titers were found in patients with proven/probable IC as well as increasing titers more than 1/160.
Our results suggest that detection of CAGTA could be a useful biomarker for the diagnosis of proven and probable IC in critical patients during prolonged ICU stay. During the monitoring it is opportune to evaluate the titers kinetics since the clinical diagnosis of proven/probable IC coincided with increase titer from negative (<1/160) to more than 1/160.
Performance of Candida albicans germ tube antibodies (CAGTA) and its association with (1 → 3)-β-D-glucan (BDG) for diagnosis of invasive candidiasis (IC)
2019, Diagnostic Microbiology and Infectious Disease
Citation Excerpt :
Notwithstanding the several studies published on this topic, the diffusion and use of the CAGTA test in clinical microbiological laboratories remain limited. The assay needs an operator-dependent reading and is characterized by quite low sensitivity values, ranging from 53% to 84% (León et al., 2016; Martínez-Jiménez et al., 2015; Martín-Mazuelos et al., 2015; Moragues et al., 2004). Our present results confirm such overall low sensitivity (52%).
Invasive candidiasis (IC) plays an important role as severe infection. Elder population, immunocompromised individuals, and intensive care unit (ICU) patients, especially when exposed to major surgery, are the most affected. IC diagnosis and treatment are difficult because of the absence of pathognomonic signs and symptoms. In addition, culture-based examination (gold standard) is known to have low sensitivity and long time to report. All these often lead to unnecessary and costly empirical antifungal therapies, burdened also by the onset of drug resistance and serious side effects for the patient. To partially overcome these problems, in recent years, novel noncultural markers have been investigated with the aim of easily and rapidly achieving an early diagnosis of IC. Such novel markers include the pan-fungal antigen (1 → 3)-β-D-glucan (BDG) and the anti–Candida albicans germ tube antibodies (CAGTAs). We retrospectively analyzed the presence of CAGTA on −80 °C stored serum samples, where the level of BDG had been previously assessed in a prospective study conducted in the Azienda Ospedaliero–Universitaria Policlinic of Modena (Pini et al. Infection 44:223–233, 2016). In particular, we selected 29 samples from proven IC episodes and 28 from non-IC cases. The 29 IC samples had been diagnosed as infections by C. albicans (n = 16), C. glabrata (n = 8), C. parapsilosis (n = 1), C. pelliculosa (n = 1), and C. tropicalis (n = 1), while 2 samples had intrasurgery biopsies positive for yeast (compatible with Candida spp.). The 28 control samples (non-IC) included 9 sera with positive blood cultures [E. faecium (n = 5), S. pneumoniae (n = 2), P. aeruginosa + A. baumannii (n = 2)] and 19 negative blood cultures. The CAGTA immunofluorescence assay was performed using 1:40, 1:80, 1:160, and 1:320 dilutions (reference dilution, as indicated by the manufacturer). According to the protocol, the samples were evaluated by the operator-dependent optical reading based on immunofluorescence positive/negative samples. In parallel, with the aim of standardizing the reading, the fluorescence images were captured, and the data were expressed as arbitrary fluorescence units (AFU). Finally, the results were interpreted as positive or negative using a cutoff provided by receiver operating characteristic (ROC) curves (Youden index). The traditional operator-dependent optical reading and the AFU measuring protocol provided comparable information with respect to the processed samples since IC and non-IC sera were correctly identified by the 2 CAGTA reading strategies in most of the cases. Interestingly, the AFU reading enabled a semiquantitative evaluation of the samples and an objective interpretation of the results. Based on the cutoff value, the AFU-based CAGTA procedure demonstrated a sensitivity of 52% and a specificity of 89%, while BDG showed a sensitivity of 90% and a specificity of 75%; the overall accuracy was 70% and 83% for CAGTA and BDG, respectively. The association of the 2 markers greatly increased both sensitivity and accuracy to 97% and 84%, respectively. As expected, when excluding non–C. albicans episodes, the sensitivity of CAGTA increased from 52% to 86%; moreover, with the exclusion of the non–deep-seated episodes, the sensitivity of CAGTA increased to 67% and reached 100% for C. albicans deep-seated candidiasis. Finally, when evaluating the influence of colonization, BDG demonstrated the most drastic decrease in specificity that dropped from 88% in noncolonized to 58% in colonized patients. With the exception of non–C. albicans episodes, CAGTA is a good marker of IC, particularly in the presence of deep-seated candidiasis. The performance of CAGTA greatly increases when used in combination with BDG.
Métodos microbiológicos para el diagnóstico, manejo y estudio de la infección fúngica invasora
2014, Enfermedades Infecciosas y Microbiologia Clinica
Las infecciones fúngicas invasoras (IFI) son infecciones de difícil diagnóstico y causan una alta mortalidad a una amplia variedad de enfermos. Debido a las limitaciones del cultivo microbiológico, se han desarrollado otras técnicas diagnósticas, entre las que destacan la determinación sérica de galactomanano o beta-1,3-d-glucano, y los anticuerpos antimicelio y antimanano. La aplicación de la biología molecular y la espectrometría de masas (MALDI-TOF) son esperanzadoras para la optimización del diagnóstico y el manejo de pacientes con IFI. En lo relativo a los fármacos antifúngicos, el desarrollo de nuevos puntos de corte especie-específicos para clasificar a los aislados como sensibles o resistentes, y la necesidad de monitorización sérica de azoles, merecen especial atención.
Invasive fungal infections (IFIs) are difficult to diagnose and cause a high mortality to an expanding spectrum of patients. Culture of clinical samples has limitations for the diagnosis of IFI and alternative procedures have been developed. Among them, serum determination of galactomannan or beta-1,3-d-glucan, and antimicelium and antimannan antibodies are relevant. The use of molecular procedures and mass spectrometry (MALDI-TOF) are encouraging tools for the optimization of the diagnosis and management of patients with IFI. The proposal of species-specific breakpoint to classify the isolates as resistant or susceptible to antifungal agents and the necessity of monitor the azole serum levels deserve greater attention.
Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC) guidelines for the diagnosis of invasive fungal infections. 2010 Update
2011, Enfermedades Infecciosas y Microbiologia Clinica
Este texto incluye una actualización de las recomendaciones sobre el diagnóstico de la infección fúngica invasora de la Sociedad Española de Microbiología Clínica y Enfermedades Infecciosas (SEIMC) elaboradas en 2004 (Enferm Infecc Microbiol Clin. 2004, 22:32-9). En la actualización de 2010 se incluye una revisión exhaustiva de las novedades tecnológicas de los últimos años, así como los niveles de evidencia para recomendar cada una de las técnicas de diagnóstico. En primer lugar, se analizan los métodos convencionales, examen microscópico y cultivo, con sus limitaciones, lo que ha llevado a desarrollar métodos alternativos como la cuantificación de antígenos y de ADN fúngico. Las indicaciones de los métodos alternativos se analizan para las diferentes infecciones fúngicas, candidiasis, aspergilosis y micosis invasoras por otras especies. Por último, se incluye una breve descripción de los métodos de identificación molecular y se revisan las pruebas para realizar estudios de sensibilidad a los antifúngicos, los procedimientos de referencia, las técnicas comerciales y sus indicaciones.
These guidelines are an update of recommendations for the diagnosis of invasive fungal infections by the Spanish Society of Clinical Microbiology and Infectious Diseases (SEIMC) published in 2004 (Enferm Infecc Microbiol Clin. 2004, 22:32-9). In this updated version of the guidelines, a comprehensive review of the most recent diagnostic innovations and levels of evidence to recommend those diagnostic procedures are included. We first analyse conventional diagnostic methods, microscopic examination and culture, underlining their limitations which have led to the development of alternative methods, such as fungal antigen and DNA quantification. Those alternative methods of diagnosis are analysed by fungal infection. We also briefly review the methods for molecular identification of fungal species and recommendations for carrying out susceptibility tests for antifungal drugs, including reference procedures, commercial techniques and their indications.
Anti-Candida albicans germ tube antibodies reduce in vitro growth and biofilm formation of C. albicans
2019, Revista Iberoamericana de Micologia
Invasive candidiasis by Candida albicans is associated with high morbidity and mortality, due in part to the late implementation of an appropriate antifungal therapy hindered by the lack of an early diagnosis.
We aimed to evaluate the in vitro antifungal activity of the antibodies against C. albicans germ tubes (CAGTA) raised in a rabbit model of candidemia.
We measured the effect of CAGTA activity by colorimetric XTT and crystal violet assays, and colony forming units count, both on C. albicans planktonic cells and during the course of biofilm formation and maturation. Viability and cell morphology were assessed by optical, fluorescent or scanning electron microscopy.
CAGTA ≥50 μg/ml caused a strong inhibition of C. albicans blastospores growth, and DiBAC fluorescent staining evidenced a fungicidal activity. Moreover, electron microscopy images revealed that CAGTA induced morphological alterations of the surface of C. albicans germ tubes grown free as well as in biofilm. Interestingly, CAGTA ≥80 μg/ml reduced the amount of C. albicans biofilm, and this effect started at the initial adhesion stage of the biofilm formation, during the first 90 min.
This is the first report showing that CAGTA reduce C. albicans growth, and impair its metabolic activity and ability to form biofilm in vitro. The antigens recognized by CAGTA could be the basis for the development of immunization protocols that might protect against Candida infections.
La infección invasora por Candida albicans está asociada a altas tasas de morbimortalidad, en parte debido al retraso en la instauración de una terapia antifúngica adecuada, dificultada a su vez por la falta de un diagnóstico precoz.
Evaluar la actividad antifúngica de los anticuerpos contra tubos germinales de C. albicans (CAGTA) obtenidos a partir de un modelo animal de candidemia en conejo.
El efecto de los CAGTA se evaluó mediante los ensayos colorimétricos XTT y cristal violeta, así como mediante el recuento de unidades formadoras de colonias, tanto en células planctónicas de C. albicans como en distintos estadios de formación y maduración de biopelículas. La viabilidad y la morfología de las células tratadas con CAGTA se determinó mediante microscopía óptica, de fluorescencia o electrónica (SEM).
Concentraciones de CAGTA ≥ 50 μg/ml generaban una fuerte inhibición del crecimiento de C. albicans, y su actividad se mostró fungicida. Los CAGTA producían alteraciones en la superficie de los tubos germinales desarrollados tanto a partir de células en suspensión como de células en biopelículas. Además, concentraciones de CAGTA ≥ 80 μg/ml redujeron la biomasa de biopelículas de Candida, y este efecto se desencadenaba en los primeros 90 min de su formación.
Este es el primer estudio que demuestra la capacidad de los CAGTA para reducir el crecimiento de C. albicans y su actividad metabólica, así como para alterar la formación de biopelículas in vitro. Los antígenos reconocidos por los CAGTA podrían servir de base para el desarrollo de protocolos de inmunización protectores frente a infecciones por Candida.

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Evaluación de una nueva técnica comercializada (Candida albicans IFA IgG) para el diagnóstico de la candidiasis invasivaEvaluation of a new commercial test (Candida albicans IFA IgG) for the serodiagnosis of invasive candidiasis

Introducción

Métodos

Resultados

Introduction

Methods

Results

Med Clin (Barc)

Diagnosis of systemic Candida infections

Ann Rev Microbiol

Nosocomial bloodstream infection in critically ill patients. Excess length stay, extra costs, and attributable mortality

JAMA

Diagnóstico microbiológico de las micosis

Rev Iberoam Micol

Analysis of cell wall extracts of Candida albicans by SDS-polyacrilamide electrophoresis and Western blot techniques

Infect Immun

Identification of two germ tube specific cell wall antigens of Candida albicans

Infect Immun

Detection of antibodies to Candida albicans germ-tubes in the serodiagnosis of systemic candidosis

Eur J Clin Microbiol

Value of detection of antibodies to Candida albicans germ tube in the diagnosis of systemic candidosis

Eur J Clin Microbiol Infect Dis

Simplified adsorption method for detection of antibodies to Candida albicans germ tubes

J Clin Microbiol

Detection of antibodies to Candida albicans germ tubes for the diagnosis and therapeutic monitoring of invasive candidiasis in patients with hematologic malignancies

J Clin Microbiol