Infección por Aspergillus flavus y Rhizopus oryzae complex en paciente con diabetes mellitus / Infection due to Aspergillus flavus and Rhizopus oryzae complex in a patient with diabetes mellitus

La sinusitis micótica es una condición patológica que puede presentarse en pacientes con diabetes mellitus y estar asociada a una crisis hiperglucémica. Es una entidad agresiva con complicaciones locales que incluyen afectación de la órbita y el sistema nervioso central, y compromiso vascular. A pesar del tratamiento quirúrgico y antimicótico, la mortalidad es de hasta el 75 %. Se describe el caso de una paciente con diagnóstico de cetoacidosis diabética y signos de oftalmoplejía unilateral que llevaron al estudio con resonancia magnética del sistema nervioso central; se encontraron signos de sinusitis, meningitis y cerebritis. Los estudios microbiológicos iniciales fueron negativos, y los biomarcadores galactomanano sérico y el antígeno de Cryptococcus también fueron negativos. Tras el manejo quirúrgico, se llegó a la identificación de Aspergillus flavus y Rhizopus spp. en el tejido de los senos paranasales. La paciente recibió tratamiento con posaconazol y, tras dos meses de seguimiento, había presentado mejoría clínica. La infección fúngica dual y la infección por A. flavus son entidades poco frecuentes y de relevancia clínica, sin casos presentados previamente en nuestro país por lo que este corresponde a un caso de interés clínico.

Fungal sinusitis is a pathology that can occur in patients with diabetes mellitus and be associated with a hyperglycemic crisis. It is an aggressive entity with local complications that include involvement of the orbit or the central nervous system, and vascular involvement. Despite surgical and antifungal treatment, mortality raises up to 75%. We report the case of a female patient with a diagnosis of diabetic ketoacidosis and signs of unilateral ophthalmoplegia, which led to the study with magnetic resonance imaging of the central nervous system, finding signs of sinusitis, meningitis, and cerebritis. Initial microbiological studies were negative, and biomarkers such as serum galactomannan and Cryptococcus antigen were also negative. After surgical management and the identification of Aspergillus flavus and Rhizopus spp. in sinus tissue, the patient received treatment with posaconazole and after two months of follow-up she presented clinical improvement. Dual fungal infection and infection by A. flavus are uncommon and clinically relevant entities, with no cases previously reported in our country, therefore this corresponds to a case of clinical interest.

Cutaneous mucormycosis of scalp and eyelids in a child with type I diabetes mellitus.

Scalp mucormycosis in children is extremely rare. We present a case of pediatric scalp mucormycosis caused by Rhizopus oryzae in a 9-year-old diabetic girl who was successfully diagnosed and treated with amphotericin B deoxycholate and wound debridement. At 3 months follow up, the patient was stable although she had lost her vision.

Purification and characterization of an aspartic protease from the Rhizopus oryzae protease extract, Peptidase R

Background Aspartic proteases are a subfamily of endopeptidases that are useful in a variety of applications, especially in the food processing industry. Here we describe a novel aspartic protease that was purified from Peptidase R, a commercial protease preparation derived from Rhizopus oryzae. Results An aspartic protease sourced from Peptidase R was purified to homogeneity by anion exchange chromatography followed by polishing with a hydrophobic interaction chromatography column, resulting in a 3.4-fold increase in specific activity (57.5 × 10³ U/mg) and 58.8% recovery. The estimated molecular weight of the purified enzyme was 39 kDa. The N-terminal sequence of the purified protein exhibited 63-75% identity to rhizopuspepsins from various Rhizopus species. The enzyme exhibited maximal activity at 75°C in glycine-HCl buffer, pH 3.4 with casein as the substrate. The protease was stable at 35°C for 60 min and had an observed half-life of approximately 30 min at 45°C. Enzyme activity was not significantly inhibited by chelation with ethylenediamine tetraacetic acid (EDTA), and the addition of metal ions to EDTA-treated protease did not significantly change enzyme activity, indicating that proteolysis is not metal ion-dependent. The purified enzyme was completely inactivated by the aspartic protease inhibitor Pepstatin A. Conclusion Based on the observed enzyme activity, inhibition profile with Pepstatin A, and sequence similarity to other rhizopuspepsins, we have classified this enzyme as an aspartic protease.