galactomannan and Dermatomycoses

Invasive aspergillosis is a life-threatening infectious complication in hematological patients undergoing immunosuppressive chemotherapy.. We report 29 cases of invasive aspergillosis diagnosed in the Sousse Farhat Hached hospital Hematology unit, Tunisia, between 2002 and 2010.. The most frequent disease (65.5%) was acute myeloid leukemia. All patients were severely neutropenic (<500/mm(3), mean duration=27 days). Pulmonary invasive aspergillosis was suggested in 28 (96.5%) cases. The most frequent respiratory signs were cough (64.3%), chest pain (53.6%), and hemoptysis (50%). The chest X-ray showed suggestive lesions in 60.7% of cases. CT scans revealed nodules with cavitation in 65% of cases, a halo sign in 20% of cases, and nodules in 15% of cases. Galactomannan antigenemia was positive in 88%, mycological examination positive in 51.6%, and seroconversion was noted in 35.7% of the cases. Invasive pulmonary aspergillosis was classified, according to EORTC/MSG criteria, as probable in 26 cases, possible in one case, and proven in one case. Aspergillus flavus was the dominant species in pulmonary invasive aspergillosis accounting for 73.7% of isolates. Extrapulmonary involvement was suggested in 39.3% of cases, the most frequent were sinusitis and brain abscess. Primary cutaneous aspergillosis was observed in one case. The overall mortality rate was 64.2%; the 12-week survival rate was 71.4%.. Our results are correlated to published data. A. flavus was the most frequent species in our region.

Topics: Adolescent; Adult; Aged; Antigens, Fungal; Antineoplastic Combined Chemotherapy Protocols; Aspergillosis; Aspergillus; Brain Abscess; Child; Child, Preschool; Dermatomycoses; Enzyme-Linked Immunosorbent Assay; Female; Fungemia; Galactose; Hematologic Neoplasms; Humans; Induction Chemotherapy; Invasive Pulmonary Aspergillosis; Male; Mannans; Middle Aged; Neuroaspergillosis; Neutropenia; Sinusitis; Survival Rate; Tomography, X-Ray Computed; Tunisia; Young Adult

Cutaneous models have proven useful in studies of the pathogenesis and treatment of Gram-positive bacterial infections. Because cutaneous invasive aspergillosis (IA) occurs in the clinical setting, we sought to develop a nonlethal murine cutaneous model of IA. We induced cutaneous IA in cyclophosphamide-treated nude BALB/c mice by subcutaneous injection of Aspergillus fumigatus conidia. Skin lesion areas correlated well with tissue fungal burdens, allowing dynamic visual monitoring of cutaneous infections. The cutaneous model accurately reflected alterations in A. fumigatus pathogenicity resulting from deletions of recognized virulence genes (pabaA, sidA, and pksP). Moreover, analysis of the roles of conidial and mycelial catalases revealed that the former is required for the initiation of cutaneous aspergillosis, whereas the latter contributes to its propagation. Finally, posaconazole treatment reduced skin lesion areas relative to those of untreated and fluconazole-treated controls. This novel cutaneous model system should be applicable to comparative studies of the pathogenesis, treatment, and tissue specificity of IA.

Topics: Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Catalase; Cyclophosphamide; Dermatomycoses; Disease Models, Animal; Female; Galactose; Hyphae; Immunocompromised Host; Immunosuppressive Agents; Mannans; Mice; Mice, Inbred BALB C; Mice, Nude; Mutagenesis; Skin; Spores; Triazoles; Virulence; Virulence Factors

Lipophilic yeasts of the genus Malassezia are associated with several skin diseases, such as pityriasis versicolor, Malassezia folliculitis, seborrhoeic dermatitis and atopic dermatitis, and are also increasingly associated with catheter-related fungaemia. The cell wall components of pathogenic micro-organisms behave as an antigen and/or ligand of the innate immune response. Live cells of Malassezia furfur and Malassezia pachydermatis did not react with an anti-alpha-1,2-mannoside antibody. However, they showed a strong hydrophobicity and reactivity with an anti-beta-1,3-glucan antibody compared to those of C. albicans. The cell wall polysaccharides of M. furfur and M. pachydermatis were isolated and their structures analysed by (1)H and (13)C NMR experiments. Both polysaccharides were shown to be beta-1,6-linked linear galactofuranosyl polymers with a small amount of mannan. The presence of galactomannan on cells of Malassezia species has not been described previously. The galactomannan did not react with an anti-Aspergillus fumigatus monoclonal antibody which has specificity for beta-1,5-linked galactofuranosyl residues. An anti-M. furfur antibody strongly reacted with the galactomannans of M. furfur and M. pachydermatis, but did not react with the galactomannans of Trichophyton rubrum, A. fumigatus or Fonsecaea pedrosoi. The characteristics of the anti-M. furfur antibody suggest that there is potential for diagnosis of Malassezia infections by antigen detection.

Topics: Animals; Antibodies, Fungal; Antibodies, Monoclonal; Antigens, Fungal; Cell Wall; Dermatomycoses; Galactose; Magnetic Resonance Spectroscopy; Malassezia; Mannans; Protein Binding; Rabbits

The monoclonal antibody EB-A1 to galactomannan is apparently specific for detecting Aspergillus species and Penicillium marneffei in formalin-fixed, paraffin-embedded tissues. It reveals hyphae, remnants of filaments, and organisms in the cytoplasm of some phagocytic cells.

Topics: Antibodies, Monoclonal; Aspergillosis; Cell Wall; Cytoplasm; Dermatomycoses; Galactose; Humans; Immunohistochemistry; Liver Diseases; Lung Diseases, Fungal; Mannans; Phagocytes