Project description:BackgroundFew cases of scedosporiosis have been reported in animals, but the true prevalence is probably underestimated due to a lack of awareness. Scedosporiosis in dogs has often been associated with localized infection (i.e., nasal infection, eumycetoma, or keratomycosis) or, in rare cases, disseminated infections.Case presentationThis case report describes the clinical and pathological features and the diagnostic process of a rare systemic and fatal fungal infection in a dog caused by Scedosporium apiospermum. A 10-month-old female Maremmano-Abruzzese sheepdog showing weakness, lethargy, lateral decubitus, miosis and muscular rigidity was presented. Rodenticide poisoning was clinically suspected for the differential diagnosis. However, postmortem examinations revealed the presence of a swollen and soft subcutaneous nodule located near the right inguinal breast, which was associated with massive enlargement of the inguinal lymph nodes and small disseminated, cream-colored nodules in the kidneys and mesentery. Multiple fungal pyogranulomas were observed upon histological examination. Fungal isolation from the kidneys, breast and inguinal lymph nodes was performed. The internal transcribed spacer (ITS) sequences from the fungal colony DNA were searched in BLAST in the NCBI GenBank for species identification. The sequences of the fungi isolated from the kidney and breast cultures showed 100% sequence identity with sequences from Scedosporium apiospermum.ConclusionsThis report shows that Scedosporium apiospermum may act as a primary pathogen in young and apparently healthy dogs and represents an important pathogen that should be considered during the diagnostic process, particularly when a fungal infection is suspected.
Project description:Cystic fibrosis (CF) causes a variety of symptoms in different organs, but the majority of the morbidity and mortality of CF is related with pulmonary conditions. Primary infections are usually bacterial, and when treated with antibiotics, yeast infections appear or become more evident. Studies show that different microorganisms can co-inhabit the same environment and the interactions could be synergistic or antagonistic. Using techniques including viable and non-viable cell-to-cell interactions, mixed culture in liquid, and solid media sharing or not the supernatant, this study has evaluated interactions between the fungal species Scedosporium apiospermum and Scedosporium boydii with the bacterial species Staphylococcus aureus, Pseudomonas aeruginosa, and Burkholderia cepacia. Cell-to-cell interactions in liquid medium showed that P. aeruginosa and B. cepacia were able to reduce fungal viability but only in the presence of alive bacteria. Interactions without cell contact using a semi-permeable membrane showed that all bacteria were able to inhibit both fungal growths/viabilities. Cell-free supernatants from bacterial growth reduced fungal viability in planktonic fungal cells as well as in some conditions for preformed fungal biomass. According to the chemical analysis of the bacterial supernatants, the predominant component is protein. In this work, we verified that bacterial cells and their metabolites, present in the supernatants, can play anti-S. apiospermum and anti-S. boydii roles on fungal growth and viability.
Project description:An extracellular proteinase produced by the filamentous fungus Scedosporium apiospermum has been purified and characterized. Initially, in vitro conditions for enzyme synthesis were investigated. The highest yield of enzyme production was obtained when the fungus was cultivated in modified Czapek-Dox liquid medium supplemented with 0.1% bacteriological peptone and 1% (w/v) glucose as the nitrogen and carbon sources respectively. Purification to homogeneity of the proteinase was accomplished by (NH4)2SO4 precipitation, followed by gel filtration through Sephadex G-75 and finally affinity chromatography through immobilized phenylalanine. Analysis of the purified enzyme by SDS/PAGE revealed a single polypeptide chain with an apparent molecular mass of 33 kDa. Further investigation of its physical and biochemical properties disclosed numerous similarities with those of the previously described serine proteinase of Aspergillus fumigatus. The enzyme was not glycosylated and its pI was 9.3. Proteinase activity was optimum between 37 and 50 degrees C and at pH 9.0, but remained high within a large range of pH values between 7 and 11. The inhibition profile and N-terminal amino acid sequencing confirmed that this enzyme belongs to the subtilisin family of serine proteinases. In agreement with this, the specific synthetic substrate N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide proved to be an excellent substrate for the proteinase with an estimated Km of 0.35 mM. Like the alkaline proteinase of A. fumigatus, this enzyme was able to degrade human fibrinogen, and thus may act as a mediator of the severe chronic bronchopulmonary inflammation from which cystic fibrosis patients suffer.
Project description:Although severe cases of invasive mycoses of different hypoxic and anoxic body parts have been reported, growth and drug susceptibility of fungal pathogens under anaerobic conditions remains understudied. The current study evaluated anaerobic growth potential and drug susceptibility of environmental Scedosporium apiospermum isolates under aerobic and anaerobic conditions. All tested strains showed equivalent growth and higher sensitivity to tested antifungal drugs under anaerobic conditions with lower minimum inhibitory concentration (MIC) as compared to aerobic conditions. Antifungal azoles were effective against isolates under both aerobic and anaerobic conditions. Most strains were resistant to antifungal echinocandins and polyenes under aerobic conditions but exhibited sensitivity under anaerobic conditions. This study provides evidence that resistance of S. apiospermum to antifungal drugs varies with oxygen concentration and availability and suggests re-evaluating clinical breakpoints for antifungal compounds to treat invasive fungal infections more effectively.