Introduction: The incidence of Aspergillus infections has been on the rise due to an increase in immunocompromised groups. Aspergillus fumigatus is one of the most important microorganisms in clinical mycology, being implicated in a number of infectious diseases in immunocompromised individuals and its effect is intensified due to its ability to produce gliotoxin. Gliotoxin, an immunosuppressive, apoptotic and cytotoxic epipolythiodoxopiperizine toxin, is the most documented and studied of the mycotoxins secreted by A. fumigatus. This study investigated the prevalence of Aspergillus in upper-respiratory infections at a referral hospital (Durban, South Africa).
Methods: Thirty-six fungal samples (2015-16) were obtained from the hospital and were identified using phenotypic identification (Biolog) and 18S rDNA. The isolates were grown on malt extract agar (MEA)and potato dextrose agar (PDA) at 37°C and 30°C. The isolates resistance to commonly used antifungal drugs were tested.
Results: Of the 36 samples, 26 were identified as A. fumigatus, two were A. flavus and eight were A. niger.All the isolates were found to grow optimally at 37°C compared to 30°C, with MEA supporting faster growth and sporulation rates compared with PDA. Generally, A. niger and A. flavus isolates were more susceptible to voriconazole compared to A. fumigatus at concentrations of 0.125-0.38 µg/ml. When posconazole was used, most of the isolates were inhibited at concentrations of 6-8 µg/ml with a few A fumigatus isolates showing resistance at higher concentrations (12-16 µg/ml).
Conclusion: Aspergillus is the prevalent mould in upper-respiratory infections with A. fumigatus, the prevalent species. A. fumigatus, A. niger and A. flavus are more susceptible to voriconazole than to posconazole.
Full conference title:
- AAA 8th (2018)