María-Dolores Moragues

Utilidad de la detección de (1→3)-ß-D-glucano y anticuerpos anti-micelio de Candida albicans para el diagnóstico y seguimiento terapéutico de la candidiasis invasora en pacientes neutropénicos adultos

Resumen Se ha evaluado la utilidad de la deteccion dos veces por semana de s-glucano (BG) y de anticuerpos anti-micelio de Candida albicans (CAGT) para el diagnostico y el seguimiento de la candidiasis invasora (CI) en 35 episodios de pacientes neutropenicos de alto riesgo. Se diagnosticaron tres casos de CI probada y tres probables. Se alcanzaron resultados positivos para ambos marcadores en el 100% de las CI probadas y en el 66% de las CI probables. La sensibilidad, especificidad, valores predictivos positivo y negativo para la deteccion de BG y anticuerpos contra CAGT fueron 83,3%, 89,6%, 62,5% y 96,3%, y 83,3%, 86,2%, 55,5% y 96,1%, respectivamente. El porcentaje de falsos positivos para BG y anticuerpos contra CAGT fue del 10,3% y 13,8% para la deteccion de BG y anticuerpos anti-CAGT, respectivamente. Sin embargo, los pacientes con resultados falsos positivos fueron diferentes para cada prueba. Ambas pruebas se anticiparon al diagnostico clinico y radiologico, asi como al inicio de la terapia antifungica en la mayoria de los pacientes. La combinacion de ambas pruebas mejoro la especificidad y el valor predictivo positivo hasta el 100%.

A prospective comparison of galactomannan in bronchoalveolar lavage fluid for the diagnosis of pulmonary invasive aspergillosis in medical patients under intensive care: comparison with the diagnostic performance of galactomannan and of (1→ 3) – β – d-glucan chromogenic assay in serum samples

Diagnosis of fungal pneumonia (FP) in critically ill patients is challenging. Circulating biomarkers for the diagnosis of FP have limitations and the combination of different assays in serum samples and directly from the target organ may further improve the diagnosis of FP. We prospectively assessed the diagnostic utility of paired galactomannan (GM) in bronchoalveolar lavage fluid (BAL) and serum GM and (1→3)-β-D-glucan (BG) assays in critically ill patients at risk of FP. Patients with FP were classified according to European Organisation for Research and Treatment of Cancer-Mycoses Study Group criteria, with modifications. Out of 847 admissions, 51 patients were eligible. There were nine invasive aspergillosis (IA) cases (four proven, five probable), three proven Pneumocysitis jirovecii pneumonia (PJP) cases and one mixed FP case (probable IA and proven PJP). The diagnostic accuracy as given by the area under the receiver operating characteristic curve in IA cases (proven and probable) for GM in BAL was 0.98 (95% CI, 0.94-1.00), whilst for GM and BG in serum it was 0.85 (95% CI, 0.74-0.96) and 0.815 (95% CI, 0.66-0.96), respectively. For IA cases (proven and probable) AUC for GM in BAL was significantly higher than GM and BG in serum (p 0.025 and p 0.032, respectively). In one of four proven and one of six probable IA cases, GM in serum remained negative, whereas GM in BAL was positive. In patients with IA, GM (90%) and BG (80%) appeared a mean of 4.3 days (range, 1-10 days) before Aspergillus was cultured. GM detection in BAL appears to improve the diagnosis of IA in critical patients.

Pga13 in Candida albicans is localized in the cell wall and influences cell surface properties, morphogenesis and virulence.

The fungal cell wall is an essential organelle required for maintaining cell integrity and also plays an important role in the primary interactions between pathogenic fungi and their hosts. PGA13 encodes a GPI protein in the human pathogen Candida albicans, which is highly up-regulated during cell wall regeneration in protoplasts. The Pga13 protein contains a unique tandem repeat, which is present five times and is characterized by conserved spacing between the four cysteine residues. Furthermore, the mature protein contains 38% serine and threonine residues, and therefore probably is a highly glycosylated cell wall protein. Consistent with this, a chimeric Pga13-V5 protein could be localized to the cell wall, but only after deglycosylation was performed. Disruption of PGA13 led to increased sensitivity to Congo red, Calcofluor white, and zymolyase, and to a diminished ability of protoplasts to recover their cell wall. In addition, pga13Δ mutants exhibited delayed filamentation, a higher surface hydrophobicity, and increased adherence and flocculation (cell-cell interactions). Furthermore, transcript profiling showed that expression of four members of the ALS family (adhesin-encoding genes) is up-regulated in the pga13Δ null mutant. Altogether, these results indicate that Pga13 is a wall-localized protein that contributes to cell wall synthesis and is important for acquiring normal surface properties. The contribution of Pga13 to surface hydrophilicity may be important for cell dispersal during development of invasive infections, and possibly for morphological development. This is consistent with the observed reduced virulence of pga13Δ mutants in a mouse model of disseminated candidiasis.

Invasive infections caused by Saprochaete capitata in patients with haematological malignancies: Report of five cases and review of the antifungal therapy

BACKGROUND Saprochaete capitata (formerly known as Geotrichum capitatum and Blastoschizomyces capitatus) is a ubiquitous fungus found in soil, water, air, plants and dairy products. It colonizes the skin, and bronchial and intestinal tract of healthy people producing serious opportunistic infections in patients with haematological malignancies, especially in those with acute leukaemia. Since 1960s its presence is being increasingly recognized in this group of patients. The clinical spectrum of S. capitata disseminated infections is very similar to that produced by Candida, being easily misinterpreted. The associated high mortality and low susceptibility to fluconazole and echinocandins of S. capitata require the acknowledgement of this emergent infection so that it can be properly treated. CASE REPORT We report 5 new cases of S. capitata disseminated infection in patients with advanced haematological malignancies observed in the haematology unit between the years 2004 and 2010, and review the state-of-the-art for diagnosis and treatment of this infection. CONCLUSIONS Based on our experience, the prophylactic use of or the empirical antifungal treatment with fluconazole and/or echinocandins would not be adequate for oncohaematological patients in those hospitals where S. capitata infection may be highly prevalent.

Detection of anti-Candida albicans IgE antibodies in vaginal washes from patients with acute vulvovaginal candidiasis

Vaginal washes from 55 women were investigated by means of an ELISA method for the presence of IgE antibodies against Candida albicans. These antibodies were detected in 87.1% of patients with clinical acute vulvovaginal candidiasis (group I), 100% of patients with suspected vulvovaginal candidiasis but negative by microscopy and culture (group II), 0% of asymptomatic carriers (group III) and 33.3% of uninfected controls (group IV). Statistically significant differences were observed comparing groups I and II vs. groups III and IV. The highest IgE vaginal antibody titers were mostly at the expense of serotype A C. albicans strains, which represented 83.3% of the C. albicans isolates. Non-C. albicans species also showed very low IgE levels. No correlation between serum and vaginal IgE was found. Furthermore, a second determination of vaginal IgE levels was performed in 3 patients. A decrease in IgE levels concomitant to a decline in clinical symptoms was observed in all of them after treatment.

Influence of Environmental pH on the Reactivity of Candida albicans with Salivary IgA

Salivary secretory IgA reacts with a group of heat-shock mannoproteins preferentially expressed on Candida albicans yeast cells and germ tubes grown at 37°C. Since other environmental factors can also modulate the expression of those antigens, we have investigated the influence of the pH of the culture medium on the expression of the antigens reacting with human salivary IgA by C. albicans. By indirect immunofluorescence, yeast cells grown in Sabouraud glucose broth at 37°C showed a statistically significant increase in reactivity with salivary IgA (p < 0.0001) when compared with cells grown at 25°C at the 4 pH values studied (3.3, 5.9, 7.5, and 9.5), the highest reactivity and the major heat-shock effect being observed at pH 5.9. The decrease in reactivity with salivary IgA observed in C. albicans cells grown at pH values of 3.3 and 9.5 was confirmed by Western blotting. Salivary IgA reacted with polydispersed materials from the cell walls of molecular masses > 55 kDa, which were more expressed at neutral pH than at acidic or alkaline pH values. A similar reactivity was observed when the antigenic extracts were stained with an antiserum directed against oligosaccharides present in antigen 6 of C. albicans serotype A. The differences in reactivity presented by salivary IgA may be related to a decrease in the expression of polysaccharides present on the surfaces of the yeast cells of C. albicans grown at acidic or alkaline pH values. The low reactivity of salivary IgA with C. albicans cells grown at acidic pH values may help to explain the association between acidic saliva and the carriage of Candida in the oral cavity, as well as with oral candidiasis.

Aislamiento de Issatchenkia occidentalis en el esófago de un paciente con leucemia

Issatchenkia occidentalis was isolated from an esophageal biopsy of a young leukemic male patient who underwent bone marrow transplantation. At the time the specimen was collected, the patient was also suffering from esophageal herpetic lesions. The identification of the isolate was not possible by the use of the available commercial methods. Thus, its identification was done by PCR and DNA sequencing using panfungal primers.

Disseminated fusariosis and hematologic malignancies, a still devastating association. Report of three new cases.

BACKGROUND Fungi of the genus Fusarium are primarily plant pathogens and saprobes that produce disseminated infections in immunologically deficient humans. After aspergillosis, disseminated fusariosis is the second most common cause of invasive infection by filamentous fungi in patients with hematologic malignancies or those undergoing transplants of hematopoietic progenitors. AIMS Disseminated fusariosis (DF) is considered an extremely rare infection and has reached a stable incidence rate, but its high mortality rate and the lack of an optimal management protocol have raised increasing interest in this mycosis. METHODS We present three cases of DF produced by Fusarium oxysporum species complex, Fusarium solani species complex and the highly unusual Fusarium dimerum in patients with advanced hematological malignancies diagnosed in our hospital between 2007 and 2011. The species level identification of the Fusarium isolates was established by sequencing their TEF1 gene. RESULTS The isolates showed low susceptibility to most of the antifungal agents analyzed, except that observed for F. dimerum to amphotericin B (AmB) and terbinafine, and F. oxysporum species complex to AmB. Interestingly, the strain of F. solani species complex exhibited high MIC values for AmB and voriconazole, notwithstanding these drugs were used for treatment with good results. Other relevant aspects to be considered in the treatment of DF are surgically cleaning foci of infection, withdrawing presumably contaminated catheters and recovery from neutropenia. CONCLUSIONS The prevention of infection in colonized patients, the maintenance of a high level of diagnostic suspicion for early diagnosis, and the combined, vigorous and prolonged use of L-AmB and voriconazole are essential to decrease the mortality rate of this devastating infection.

Molecular Identification of Saprochaete capitata in Human Blood and Paraffinized Tissue Samples

Invasive fungal infections (IFIs) caused by Candida and Aspergillus species are the most prevalent fungal infections in hospitals; however, those caused by rare fungal species have become increasingly common in recent years. Saprochaete capitata (anamorph; Magnusiomyces capitatus teleomorph),