Case Report: Coral Reef Pathogen Aspergillus sydowii Causing Black Grain Mycetoma.

Mycetoma is an infrequent subcutaneous infection caused by true fungi (eumycetoma) or aerobic actinomycetes (actinomycetoma). We report the case of a 62-year-old man with eumycetoma involving the left foot and ankle. Skin biopsy revealed black-brown grains, and in culture, a white colony fungus grew at day 8. Molecular sequencing using ITS1-ITS4 primers identified the species as Aspergillus sydowii. The patient was treated with itraconazole 200 mg twice daily and terbinafine 250 mg daily for 8 months, with complete response and no recurrence after 2.5 years of follow-up. Aspergillus sydowii is a saprotrophic fungus that rarely causes skin or nail disease. No cases of eumycetoma caused by this agent have been previously reported. As its geographic distribution continues to expand, it may increasingly be recognized as a cause of human disease.

Ex vivo infection of murine precision-cut lung tissue slices with Mycobacterium abscessus: a model to study antimycobacterial agents.

BACKGROUND: Multidrug-resistant infections due to Mycobacterium abscessus often require complex and prolonged regimens for treatment. Here, we report the evaluation of a new ex vivo antimicrobial susceptibility testing model using organotypic cultures of murine precision-cut lung slices, an experimental model in which metabolic activity, and all the usual cell types of the organ are found while the tissue architecture and the interactions between the different cells are maintained. METHODS: Precision cut lung slices (PCLS) were prepared from the lungs of wild type BALB/c mice using the Krumdieck® tissue slicer. Lung tissue slices were ex vivo infected with the virulent M. abscessus strain L948. Then, we tested the antimicrobial activity of two drugs: imipenem (4, 16 and 64 µg/mL) and tigecycline (0.25, 1 and 4 µg/mL), at 12, 24 and 48 h. Afterwards, CFUs were determined plating on blood agar to measure the surviving intracellular bacteria. The viability of PCLS was assessed by Alamar Blue assay and corroborated using histopathological analysis. RESULTS: PCLS were successfully infected with a virulent strain of M. abscessus as demonstrated by CFUs and detailed histopathological analysis. The time-course infection, including tissue damage, parallels in vivo findings reported in genetically modified murine models for M. abscessus infection. Tigecycline showed a bactericidal effect at 48 h that achieved a reduction of > 4log10 CFU/mL against the intracellular mycobacteria, while imipenem showed a bacteriostatic effect. CONCLUSIONS: The use of this new organotypic ex vivo model provides the opportunity to test new drugs against M. abscessus, decreasing the use of costly and tedious animal models.

Evaluation of the intracellular activity of drugs against Mycobacterium abscessus using a THP-1 macrophage model.

We evaluated the antimicrobial effectiveness against M. abscessus in a THP-1 cell line model. No intracellular activity was observed when using amikacin or imipenem. A bacteriostatic effect was observed for cefoxitin, clarithromycin and azithromycin. Tigecycline showed the best antibacterial effect by decreasing the intracellular growth up to bactericidal level.

Draft Genome Sequence of Actinomadura madurae LIID-AJ290, Isolated from a Human Mycetoma Case.

Here we present the draft genome sequence of a member of the Thermomonosporaceae, Actinomadura madurae LIID-AJ290, isolated from a human case of mycetoma. The assembly contains 10,308,866 bp. This is to our knowledge the first reported genome of a human-pathogenic Actinomadura species.