Renée Grillot

Detection of Circulating Aspergillus fumigatus Galactomannan: Value and Limits of the Platelia Test for Diagnosing Invasive Aspergillosis

ABSTRACT The effectiveness of galactomannan detection with the Platelia test was evaluated in a prospective study of 3,327 sera from 807 patients. The specificity was 99.6% (748 of 751 cases). For the groups of patients with proven and probable invasive aspergillosis, the sensitivity was 50.0% (17 of 34 cases). The disappointing sensitivity associated with the presence of rare false-positive cases underlines the limits of this test.

Human Dendritic Cells following Aspergillus fumigatus Infection Express the CCR7 Receptor and a Differential Pattern of Interleukin-12 (IL-12), IL-23, and IL-27 Cytokines, Which Lead to a Th1 Response

ABSTRACT Aspergillus fumigatus is the most prevalent airborne fungal pathogen and causes fatal invasive aspergillosis in immunocompromised patients. Given the essential role of dendritic cells (DC) in initiating and regulating immune responses, we investigated the impact of A. fumigatus conidial infection on human DC. A. fumigatus conidia were rapidly internalized and induced the release of tumor necrosis factor alpha within the first 8 h. After A. fumigatus infection, the majority of DC underwent full maturation, although CCR7 expression was observed only in DC that had internalized the conidia. Additionally, the analysis of regulatory cytokines showed that infected DC simultaneously produced interleukin-12p70 (IL-12p70) and significant amounts of IL-10. IL-10 neutralization was not able to further increase IL-12p70 production from infected DC. Whereas the central role of IL-12 in the generation of Th1 cells has long been appreciated, recently two other members of the IL-12 family, IL-23 and IL-27, were reported to play important roles in the regulation of gamma interferon (IFN-γ) production from naïve and memory T cells. A. fumigatus-infected DC were also able to express high levels of IL-23p19 and low levels of IL-27p28 at later stages of infection. According to this expression pattern, A. fumigatus-infected DC were able to prime IFN-γ production of naïve T cells. Thus, this study on the expression of the new IL-12 family members controlling the Th1 response sheds light on a novel aspect of the contribution of DC to anti-Aspergillus immunity.

Uneven Distribution of Mating Types among Genotypes of Candida glabrata Isolates from Clinical Samples

ABSTRACT In order to shed light on its basic biology, we initiated a population genetic analysis of Candida glabrata, an emerging pathogenic yeast with no sexual stage yet recognized. A worldwide collection of clinical strains was subjected to analysis using variable number of tandem repeats (VNTR) at nine loci. The clustering of strains obtained with this method was congruent with that obtained using sequence polymorphism of the NMT1 gene, a locus previously proposed for lineage assignment. Linkage disequilibrium supported the hypothesis of a mainly clonal reproduction. No heterozygous diploid genotype was found. Minimum-spanning tree analysis of VNTR data revealed clonal expansions and associated genotypic diversification. Mating type analysis revealed that 80% of the strains examined are MATa and 20% MATα and that the two alleles are not evenly distributed. The MATa genotype dominated within large clonal groups that contained only one or a few MATα types. In contrast, two groups were dominated by MATα strains. Our data are consistent with rare independent mating type switching events occurring preferentially from type a to α, although the alternative possibility of selection favoring type a isolates cannot be excluded.

Aspergillus Conidia Activate the Complement by the Mannan-Binding Lectin C2 Bypass Mechanism

Innate immunity is the major host defense against invasive aspergillosis. To determine whether the collectin mannan-binding lectin (MBL) is involved in the initial protective immunity through complement activation against opportunistic fungal infections caused by Aspergillus, we performed in vitro studies on 29 different strains of Aspergillus conidia from five different species. Incubation of Aspergillus conidia in human normal serum leads to activation of the alternative pathway, whereas neither the classical nor the lectin pathways through C4 and C2 cleavage are activated. Complement response to conidia was investigated using a MBL-deficient serum and reconstitution experiments were conducted with MBL/MASPs complexes. We found that MBL can directly support C3 activation by a C2 bypass mechanism. Finally, a stronger activation of the alternative pathway was observed for the clinical strains isolated from patients with invasive aspergillosis, compared with the environmental strains.

Evaluation of Candida ID, a New Chromogenic Medium for Fungal Isolation and Preliminary Identification of Some Yeast Species

ABSTRACT Candida ID, a new chromogenic medium, allows identification ofCandida albicans (blue colonies) and preliminary identification into a group of four species (pink colonies). In comparison with Albicans ID2 and Sabouraud gentamicin chloramphenicol on 446 fungal strains, Candida ID allowed the isolation of more species than Albicans ID 2 (95.5% versus 91.2%).

Multivariate analysis comparing microbial air content of an air-conditioned building and a naturally ventilated building over one year

Heating, ventilation and air-conditioning (HVAC) may be responsible for the production and spread of airborne microorganisms in office buildings. In order to compare airborne microbiological flora in an air-conditioned building with that in a naturally ventilated building, eight sets of measurements were made over a 1-year period. Concurrently with other environmental measurements, air samples were collected in each building, from three offices and from the outdoor air, using the Andersen single-stage sampler. Three different media were used to culture fungi, staphylococci and mesophilic bacteria. Multivariate analysis revealed a group of offices more contaminated than others, and a marked seasonal variation in fungal concentrations. A comparison of mean levels of microorganisms measured in the two buildings showed that the air microbial content was significantly higher and more variable in the naturally ventilated building than in the air-conditioned building. Moreover, in the naturally ventilated building, the interior fungal content was strongly dependent on the outdoor content, while in the air-conditioned building fungal concentrations remained constant despite significant variations measured outside. This was confirmed by a statistical comparison of the correlation coefficients between indoor and outdoor concentrations. No difference was observed regarding gaseous pollutants and temperature, but relative humidity was significantly higher in the air-conditioned building. The effect of HVAC was to prevent the intake of outdoor particles and to dilute the indoor concentrations. These results are consistent with the presence of high-efficiency filters and a steam humidifier in the HVAC system under study.

Recombinant Allergens Combined with Biological Markers in the Diagnosis of Allergic Bronchopulmonary Aspergillosis in Cystic Fibrosis Patients

ABSTRACT Allergic bronchopulmonary aspergillosis (ABPA) is a frequent complication in cystic fibrosis patients. The diagnosis remains difficult and requires a combination of clinical, radiological, biological, and mycological criteria. The aim of this study was to analyze the added value of two recombinant antigens, rAspf4 and rAspf6, associated with the detection of specific IgG; precipitins; total IgE; and Aspergillus fumigatus in sputum for the diagnosis of ABPA. In a retrospective study, we determined the specific IgE responses to these recombinants in 133 sera of 65 cystic fibrosis patients. We selected an average of five serum samples from each of the 17 patients with ABPA (13 proven and 4 probable ABPA) and from 3 patients with Aspergillus bronchitis and rhinosinusitis. One serum sample for the 45 patients without ABPA was tested. The sensitivity of specific IgE detection against rAspf4 calculated per patient (92.3%) was significantly higher (P < 0.05) than that of rAspf6 (53.8%). When rAspf4 IgE detection was associated with anti-Aspergillus IgG enzyme-linked immunosorbent assay (ELISA) and precipitin detection, the sensitivity rose to 100%. The specificities of rAspf4 and rAspf6 IgE detection were 93.7% and 91.6%, respectively. Other diagnostic criteria had slightly lower specificities (87.5% for anti-Aspergillus IgG ELISA, 89.6% for precipitins, 84.4% for total IgE, and 85.0% for positive A. fumigatus culture in sputum). In conclusion, this retrospective study showed the relevance of rAspf4 IgE detection, in combination with other biological markers (Aspergillus IgG ELISA, precipitins, and total IgE), for improving the biological diagnosis of ABPA.

Severe filamentous fungal infections after widespread tissue damage due to traumatic injury: Six cases and review of the literature

We describe 6 cases of severe filamentous fungal infections after widespread tissue damage due to traumatic injury in previously healthy people. Additionally, we report 69 cases from an exhaustive 20-y review of the literature to investigate the epidemiological and clinical features, the prognosis and the therapeutic management of these post-traumatic severe filamentous fungal infections. Traffic (41%) and farm accidents (25%) were the main causes of injury, which involved either the limbs only (41%) or multiple sites (41%). Necrosis was the main symptom (60%) and Mucorales (72%) and Aspergillus (11%) were the 2 most frequent fungi causing infection. These infections required substantial surgical debridement or amputation (96%) associated with aggressive antifungal therapy (81%), depending on the responsible fungi. This study underlines the need for early, repeated and systematic mycological wound samples to guide and adapt surgical and antifungal management in these filamentous fungal infections.

Influence of internal and outdoor factors on filamentous fungal flora in hematology wards.

BACKGROUND Nosocomial invasive filamentous fungi infections could result from inhalation of filamentous fungi conidia present in hospital environment. METHODS The environmental fungal flora in 3 different hospital wards with similar air conditioning was prospectively studied during 30 months and compared to internal (presence of agranulocytosis patient, behavioral practices, activity, cleaning work) and outdoor factors (meteorologic data, outdoor fungi). The general preventive measures differed from one unit to another. RESULTS The hematology wards with filamentous fungi preventive measures were significantly less contaminated than a conventional ward without specific measures. Internal and outdoor factors influenced the level of fungal flora. However, the influence of internal factors was greater in the conventional ward than in hematology wards. The variation of flora in the hospital environment was seasonal, and the level of this contamination in each ward was influenced by the meteorology. However, outdoor factors more readily explain the variations of fungal load in hematology than in the conventional ward. CONCLUSION This study highlights that specific preventive measures participate significantly in the control of the filamentous fungal flora intensity due to internal factors but not those due to outdoor factors, stressing the importance of high-efficiency particulate air filtration in high-risk units.

Itraconazole in the treatment of aspergillosis: a study of 16 cases

Itraconazole, a new triazole antifungal agent, has marked in vitro activity against filamentous fungi, particularly Aspergillus. We studied three groups of patients suffering from aspergillosis (16 cases): six affected with aspergilloma, three with allergic bronchopulmonary aspergillosis and seven with invasive aspergillosis. The survey consisted in clinical, radiological, mycological and serological evaluations with respect to drug plasma levels. Itraconazole was given at a dosage of 200–400 mg day‐1 for periods ranging from 14 to 488 days. Out of the 16 patients, nine responded to therapy (recovery or improvement) and one failed to respond. Three patients improved but experienced relapses and three others could not be evaluated because of liver function disorders, so that treatment had to be stopped prematurely.