Triazole resistance in Aspergillus fumigatus isolates in Africa: a systematic review.

Emergence of triazole resistance has been observed in Aspergillus fumigatus over the past decade including Africa. This review summarizes the current published data on the epidemiology and reported mechanisms of triazole-resistant Aspergillus fumigatus (TRAF) in both environmental and clinical isolates from Africa. Searches on databases Medline, PubMed, HINARI, Science Direct, Scopus and Google Scholar on triazole resistance published between 2000 and 2021 from Africa were performed. Isolate source, antifungal susceptibility using internationally recognized methods, cyp51A mechanism of resistance and genotype were collected. Eleven published African studies were found that fitted the search criteria; these were subsequently analyzed. In total this constituted of 1686 environmental and 46 clinical samples. A TRAF prevalence of 17.1% (66/387) and 1.3% (5/387) was found in respectively environmental and clinical settings in African studies. Resistant to itraconazole, voriconazole, and posaconazole was documented. Most of the triazole-resistant isolates (30/71, 42.25%) were found to possess the TR34/L98H mutation in the cyp51A-gene; fewer with TR46/Y121F/T289A (n = 8), F46Y/M172V/E427K (n = 1), G54E (n = 13), and M172V (n = 1) mutations. African isolates with the TR34/L98H, TR46/Y121F/T289A and the G54E mutations were closely related and could be grouped in one of two clusters (cluster-B), whereas the cyp51A-M172V mutation clustered with most cyp51A-WT strains (cluster-A). A single case from Kenya shows that TR34/L98H from environmental and clinical isolates are closely related. Our findings highlight that triazole resistance in environmental and clinical A. fumigatus is a cause for concern in a number of African countries. There is need for epidemiological surveillance to determine the true burden of the problem in Africa. LAY SUMMARY: Emergence of triazole resistance has been observed in Aspergillus fumigatus. TRAF was found from environmental (17.1%) and clinical (1.3%) settings in Africa. We highlighted that triazole resistance in environmental and clinical A. fumigatus is a cause for concern in a number of African countries.

Rapid detection of Mucorales based on recombinase polymerase amplification and real-time PCR.

Mucormycosis, an invasive fungal disease with severe consequences, poses a significant threat to immunocompromised individuals. However, the timely and accurate identification of Mucorales infection continues to present difficulties. In this study, novel detection techniques utilizing recombinase polymerase amplification (RPA) and quantitative real-time polymerase chain reaction (qPCR) were developed, specifically targeting the mitochondrial rnl gene, in order to address this challenge. The specificity of the RPA and qPCR assay was assessed by adding genomic DNAs extracted from 14 non-targeted strains, as well as human and mouse blood. No false-positive results were observed. Additionally, genomic DNAs from 13 species in five genera of order Mucorales were tested and yielded positive results in both methods. To further evaluate the sensitivity of the assays, DNAs from Rhizopus oryzae, Mucor racemosus, Absidia glauca, Rhizomucor miehei, and Cunninghamella bertholletiae were utilized, with concentrations ranging from 1 ng/µL to 1 fg/µL. The limit of detection (LoD) for the RPA assay was determined to be 1 pg., with the exception of Rhizomucor miehei which had a LoD of 1 ng. The LoD for the qPCR assay varied between 10 fg and 1 pg., depending on the specific species being tested. Sensitivity analysis conducted on simulated clinical samples revealed that the LoD for RPA and qPCR assays were capable of detecting DNA extracted from 103 and 101 colony forming units (CFU) conidia in 200 µL of blood and serum, respectively. Consequently, the real-time RPA and qPCR assays developed in this study exhibited favorable sensitivity and specificity for the diagnosis of mucormycosis.