agar and Mucormycosis

Recently, India witnessed an unprecedented surge of coronavirus disease 2019 (COVID-19)-associated mucormycosis (CAM) cases. In addition to patient management issues, environmental Mucorales contamination possibly contributed to the outbreak. A recent study evaluated environment contamination by Mucorales in the hospital setting. However, a considerable number of CAM patients were never admitted to a hospital before the development of the disease. The present study, therefore, planned to evaluate Mucorales contamination of patients' residences.. The residential environment of 25 patients with CAM living in north India was surveyed. Air samples were collected from indoor and immediate outdoor vicinity of the patients' residence and cultured on Dichloran Rose-Bengal Chloramphenicol (DRBC) agar with benomyl for selective isolation of Mucorales. Surface swab samples were also collected from the air coolers fitted in those residences and cultured on DRBC agar. The isolates were identified by phenotypic and genotypic methods. Amplified fragment length polymorphism (AFLP) was employed to evaluate the genetic relatedness of the environmental and patients' clinical isolates.. The median spore count (mean ± SD, cfu/m. The study supported the view that the patients might have acquired Mucorales from the home environment during the post-COVID-19 convalescence period. Universal masking at home during patients' convalescence period and environmental decontamination could minimize exposure in those susceptible patients.

Topics: Agar; Amplified Fragment Length Polymorphism Analysis; Benomyl; Chloramphenicol; Convalescence; COVID-19; Humans; Mucorales; Mucormycosis

Triazole prophylaxis has become the norm in patients with hematological malignancies. Breakthrough infections caused by Mucorales during triazole prophylaxis remain a challenging problem. We found that preexposure of Rhizopus oryzae to antifungal triazoles (fluconazole, voriconazole, posaconazole, and itraconazole) did not modify the in vitro susceptibility of Rhizopus oryzae to posaconazole. In contrast, preexposure of Rhizopus to triazoles was associated with the enhanced in vitro susceptibility of R. oryzae to amphotericin B. Preexposure to posaconazole did not alter the virulence of R. oryzae in the fly model of mucormycosis.

Topics: Agar; Animals; Antifungal Agents; Culture Media; Disease Models, Animal; Drosophila melanogaster; Female; Fluconazole; Itraconazole; Microbial Sensitivity Tests; Mucormycosis; Rhizopus; Survival Analysis; Triazoles; Virulence; Voriconazole

Hyphal growth in filamentous fungi proceeds in an unidirectional radial pattern from a point inoculation. An inhibitor produced, secreted, and absorbed by the advancing hyphae has been speculated to account for directional growth. Working with Mucor and Aspergillus, laboratory evidence is provided for the production of an inhibitory by the advancing hyphae of these filmentous fungi that precludes back growth. Strains of Mucor and Aspergillus inoculated in agar on a 0.45-mm membrane filter placed on agar surfaces grow radially beyond the filter perimeter and onto the agar surface. Removal of the filter pad does not result in hyphal extension back into the clear zone underlying the membrane filter. Inoculation of the clear zone with a fresh Mucor or Aspergillus spore suspension does not result in hyphal growth. Instead, germinating spores show aberrant and aborted hyphae. The fungal inhibitor shows cross-reactivity between Mucor and Aspergillus, is resistant to pronase (10 mg/mL) but not chloroform inactivation, and passes through dialysis tubing with a molecular weight cutoff of 3500.

Topics: Agar; Antifungal Agents; Aspergillosis; Aspergillus; Culture Media; Humans; Micropore Filters; Mucor; Mucormycosis

Saksenaea vasiformis was identified as the causative agent in three cases of sub-cutaneous zygomycosis in Australia. The laboratory techniques for inducing clinical isolates of S. vasiformis to produce sporangia, necessary for the precise identification of the fungus, are described and compared.

Topics: Adolescent; Adult; Agar; Australia; Female; Humans; Male; Middle Aged; Mucorales; Mucormycosis; Spores, Fungal

Topics: Agar; Color; Conjugation, Genetic; Crosses, Genetic; Fungi; Genetic Variation; Humans; Mucormycosis; Spores, Fungal; Terminology as Topic