Is elevation of the serum β-d-glucan level a paradoxical sign for Trichosporon fungemia in patients with hematologic disorders?

SummaryThe detection of serum 1,3-β-d-glucan (BDG) has been reported to be useful for the diagnosis and therapeutic monitoring of various invasive fungal infections. Although Trichosporon fungemia is increasingly recognized as a fatal mycosis in immunocompromised patients, the utility of this assay for Trichosporon fungemia is still unknown. In our experience (28 cases), the level of BDG rose in about half of the patients with hematologic disorders who developed Trichosporon fungemia. Among them, early death from this infection was more frequently seen in BDG-negative patients than in BDG-positive patients. In addition, overall survival was also significantly worse in BDG-negative patients than in BDG-positive patients. There were no significant differences between these two patient groups in terms of clinical background. Unlike for other invasive fungal infections, elevation of BDG level may indicate a paradoxical sign for Trichosporon fungemia in patients with hematologic disorders

Levels of (1→3)-β-D-glucan, Candida mannan and Candida DNA in serum samples of pediatric cancer patients colonized with Candida species

<p>Abstract</p> <p>Background</p> <p>Surveillance cultures may be helpful in identifying patients at increased risk of developing invasive candidiasis. However, only scant information exists on the effect of <it>Candida </it>colonization on serum levels of diagnostic biomarkers. This prospective surveillance study determined the extent of <it>Candida </it>colonization among pediatric cancer patients and its possible impact on serum levels of (1-3)-β-D-glucan (BDG), <it>Candida </it>mannan and <it>Candida </it>DNA.</p> <p>Methods</p> <p>A total of 1075 swabs originating from oropharynx (n = 294), nostrils (n = 600), rectum (n = 28), groin (n = 50), ear (n = 54), and axilla (n = 49) of 63 pediatric cancer patients were cultured for the isolation of <it>Candida </it>spp. Patients yielding <it>Candida </it>spp. from any sites were considered as colonized. Serum samples were collected from patients at the time of first surveillance culture for detection of BDG by Fungitell kit and <it>Candida </it>mannan by Platelia <it>Candida </it>Ag. <it>Candida </it>DNA was detected by using panfungal primers and identification was carried out by using species-specific primers and DNA sequencing.</p> <p>Results</p> <p>Seventy-five (7.6%) swab cultures from 35 (55.5%) patients yielded <it>Candida </it>spp. These isolates included <it>C. albicans </it>(n = 62), <it>C. dubliniensis </it>(n = 8), <it>C. glabrata </it>and <it>C. tropicalis </it>(n = 2 each) and <it>C. krusei </it>(n = 1). Eleven patients were colonized at three or more sites. Eight of 36 serum samples from 6 colonized patients yielded BDG values higher than the currently recommended cut-off value of ≥80 pg/ml. However, none of the serum samples yielded <it>Candida </it>mannan levels ≥0.5 ng/ml and PCR test for <it>Candida </it>DNA was also negative in all the serum samples of colonized patients. During the study period, only two colonized patients subsequently developed candidemia due to <it>C. tropicalis</it>. Besides positive blood cultures, <it>C. tropicalis </it>DNA, BDG and <it>Candida </it>mannan were also detected in serum samples of both the patients.</p> <p>Conclusions</p> <p>The present study demonstrates that while mucosal colonization with <it>Candida </it>species in pediatric cancer patients is common, it does not give rise to diagnostically significant levels of <it>Candida </it>mannan or <it>Candida </it>DNA in serum specimens. However, BDG values may be higher than the cut-off value in some pediatric patients without clinical evidence of invasive <it>Candida </it>infection. The study suggests the utility of <it>Candida </it>mannan or <it>Candida </it>DNA in the diagnosis of invasive candidiasis, however, the BDG levels in pediatric cancer subjects should be interpreted with caution.</p

Beta-glucans in advanced CKD : role in endotoxaemia and inflammation

BACKGROUND/AIMS: (1-3)-β-D glucans (BG) are cellular components of yeasts and fungi. Elevated blood levels may be an adjunct in diagnosing invasive fungal infection, though can be high in dialysis patients without fungaemia. BG can also induce false positive signals in endotoxin detection assays (Limulus Amoebocyte Lysate [LAL] assay). We explored the relationship between BG levels, renal impairment, endotoxaemia and inflammation. METHODS: We measured serum BG levels, markers of inflammation and blood endotoxin levels in 20 controls, 20 with stages 1-3 chronic kidney disease (CKD), 20 with stages 4-5 CKD, 15 on peritoneal dialysis (PD) and 60 on haemodialysis (HD). Another 30 patients were studied before and after HD initiation. RESULTS: BG levels increased with advancing CKD, being highest in HD patients, 22% of whom had elevated levels (> 80 pg/ml). Levels increased significantly following HD initiation. Levels also correlated positively with CRP, TNFα, IL-6 levels, independently of CKD stage. Blood endotoxin was detectable by LAL assays in 10-53% of the CKD cohort, being most prevalent in the HD group, and correlating positively with BG levels. Adding BG blocking agent to the assay reduced endotoxin detection confining it to only 5% of HD patients. Levels of inflammatory markers were higher in those with detectable endotoxin - whether false- or true positives. CONCLUSION: BG levels increased with decreasing renal function, being highest in dialysis patients. High BG levels were associated with false positive blood endotoxin signals, and with markers of inflammation, independently of CKD stage. The cause for high BG levels is unknown but could reflect increased gut permeability and altered mononuclear phagocytic system function.Peer reviewe

Serum (1 → 3)-β-d-glucan measurement as an early indicator of Pneumocystis jirovecii pneumonia and evaluation of its prognostic value

AbstractPneumocystis jirovecii (carinii) pneumonia (PJP) is a major cause of disease in immunocompromised individuals. However, until recently no reliable and specific serological parameters for the diagnosis of PJP have been available. (1 → 3)-β-d-Glucan (BG) is a cell wall component of P. jirovecii and of various other fungi. Data from the past few years have pointed to serum measurement of BG as a promising new tool for the diagnosis of PJP. We therefore conducted a retrospective study on 50 patients with PJP and 50 immunocompromised control patients to evaluate the diagnostic performance of serum BG measurement. Our results show an excellent diagnostic performance with a sensitivity of 98.0% and a specificity of 94%. While the positive predictive value was only 64.7%, the negative predictive value was 99.8% and therefore a negative BG result almost rules out PJP. BG levels were already strongly elevated in an average of 5 days and up to 21 days before microbiological diagnosis demonstrating that the diagnosis could have been confirmed earlier. BG levels at diagnosis and maximum BG levels during follow-up did not correlate with the outcome of patients or with the P. jirovecii burden in the lung as detected by Real-Time PCR. Therefore, absolute BG levels seem to be of no prognostic value. Altogether, BG is a reliable parameter for the diagnosis of PJP and could be used as a preliminary test for patients at risk before a bronchoalveolar lavage is performed

Stellenwert von (1-3)-β-D-Glucan zur Vorhersage einer invasiven Pilzinfektion und Assoziation mit dem Schweregrad der Organdysfunktion bei kritisch kranken Patienten mit und ohne Sepsis

Die Diagnostik invasiver fungaler Infektionen (IFI) bei Patienten auf Intensivstation ist schwierig. Wichtig ist aber eine frühzeitige Diagnose zur raschen Therapieeinleitung, um die Mortalität zu senken. Kulturelle Verfahren sind zeitaufwendig und besitzen eine niedrige Sensitivität. Nichtkulturelle Verfahren sind als alleiniges Diagnostikum noch nicht in der Praxis etabliert. Diese Arbeit analysiert prospektiv monozentrisch den Stellenwert von (1-3)-β-D-Glucan (BDG) für den Nachweis einer IFI und stellt Assoziationen mit dem Schweregrad der Organdysfunktion bei kritisch kranken Patienten her. In einem Dreijahres-Zeitraum wurde BDG im Serum von 57 Patienten mit schwerer Sepsis oder septischem Schock (Gruppe 1) und von 61 Patienten nach kardiochirurgischer Operation (Gruppe 2) über sieben Tage und dann wöchentlich bis Tag 28 bestimmt. Die Messung erfolgte kolorimetrisch (MARUHA®-Testkit, Firma WAKO). Die Ergebnisse wurden mit dem Goldstandard (kultureller Candida-Nachweis) verglichen. In Gruppe 1 lagen die BDG-Werte in der ersten Woche um den Cut-Off-Wert von 11 pg/ml, während Patienten der Gruppe 2 über fünf Tage signifikant höhere BDG-Werte aufwiesen, ohne dass jedoch eine IFI vorlag. Bei neun Patienten in der Gruppe 1 war eine IFI nachweisbar. Sensitivität und Spezifität von BDG für den IFI- Nachweis zum Einschlusszeitpunkt betrugen 67 bzw. 50 %, der positive und negative prädiktive Wert 24 bzw. 88 %. Folglich schließt ein negativer BDG-Wert eine IFI nahezu aus. Die BDG-Spiegel über 28 Tage zeigten weder die Schwere der Infektion noch das Outcome an. BDG-Werte von überlebenden und verstorbenen Patienten waren nicht signifikant unterschiedlich. Gesamt-SOFA-Score und Subscores korrelierten nur schwach mit den BDGSpiegeln (Korrelationskoeffizient 0,22). Der Blutkontakt zu Fremdoberflächen wie HLM kann zu falsch hohen BDG-Werten führen können

Aspectos epidemiológicos, clínicos y de laboratorio de la candidemia en el siglo XXI

Candida spp. es responsable de alrededor del 80% de todas las infecciones fúngicas nosocomiales. Ocupa el cuarto lugar entre los microorganismos causantes de infección en el torrente circulatorio en EEUU y el séptimo en Europa. Existen numerosos estudios epidemiológicos sobre candidemia, efectuados en escenarios muy diversos, durante cortos periodos de tiempo y elaborados con distintos diseños, que coinciden en señalar que se ha producido un incremento significativo de las candidemias en las últimas dos décadas. La magnitud del incremento descrito podría obedecer a diferentes motivos. No se dispone de información que proporcione una mayor perspectiva en el tiempo que incluya un importante número de candidemias en pacientes no seleccionados, diagnosticados y tratados por un mismo equipo de profesionales, de acuerdo con una misma metodología que nos pueda proporcionar una interpretación más realista sobre los cambios producidos. La candidemia es una infección con una mortalidad que oscila entre el 29-76%, pudiendo llegar la mortalidad relacionada con la infección hasta el 49%. La evolución clínica depende no sólo de la adecuación del tratamiento sino de la gravedad de las enfermedades de base y del estado clínico del paciente. Se ha señalado que los nuevos métodos diagnósticos y terapéuticos apenas han modificado la mortalidad de forma relevante. Es necesario conocer si se ha producido algún cambio en los factores de riesgo de mortalidad de acuerdo a datos clínicos recientes y analizar si las diferencias en el abordaje de las candidemias en distintos periodos de tiempo han tenido alguna repercusión en el pronóstico. Las recomendaciones sobre el manejo de las candidemias en pacientes con catéter vascular incluyen la retirada del mismo siempre que sea posible. Aunque existen resultados contradictorios, hay publicaciones que demuestran que la retirada precoz tiene importancia pronóstica, no solo en las candidemias por catéter sino también en las primarias aunque no es infrecuente que se incluyan como candidemias primarias a infecciones que en realidad están producidas por catéter pero no se dispone de cultivo del mismo..

DEVELOPMENT OF NOVEL METHODS FOR THE DIAGNOSIS OF INVASIVE PULMONARY ASPERGILLOSIS

PhDBackground: Invasive pulmonary aspergillosis (IPA) is a common cause of mortality in haemato-oncology patients and early diagnosis is vital for improving outcomes. Since lung biopsy in this acute setting is rarely performed due to the associated risks, an empirical strategy remains the standard of care in many haematology units, but leads to overtreatment with antifungal drugs, which have significant side-effects. This project has developed novel approaches for detecting IPA, allowing early and specific treatment of genuine fungal infection. Methods: A combination marker approach involving a new Aspergillus qPCR assay, an EORTC/MSG-endorsed GM ELISA and an Aspergillus LFD, was used to establish a robust diagnosis of IPA from clinical broncho-alveolar lavage (BAL) fluid samples. The inflammatory cytokine profile associated with IPA biomarker positive BAL fluid was also evaluated. Finally, antigen and qPCR detection were combined in a proximity ligation assay (PLA), to demonstrate proof-of-principle for a diagnostic assay for the earliest possible detection of fungal infections. Results: A dual testing approach involving a novel MIQE-compliant Aspergillus qPCR assay and an Aspergillus LFD showed a sensitivity and specificity of 100% and 94%, respectively in BAL fluid, unlike in blood where this approach was not sensitive. Results confirmed previously published concerns over the repeatability of GM in serum, whereas BAL GM results appear stable. Biomarker detection results in exhaled breath condensate did not correlate well with results in BAL fluid samples. Respiratory samples did not identify a distinct inflammatory marker profile in IPA. Finally, antibodies raised against JF5 mannoprotein were used to develop a PLA test to detect active growth of Aspergillus. Conclusions: The optimised qPCR is a very sensitive and highly specific aid in IPA diagnosis. A combination biomarker approach could be incorporated into a diagnostic-driven approach to patient management to direct antifungal treatment to patients with evidence of invasive fungal disease.Barts and The London Charit