Recovery and Its Dynamics of Filamentous Fungi from Clinical Specimen Cultures: An Extensive Study

Abstract

Fungal culture is the gold standard method of diagnosing fungal infections, but important information, such as the impact of media and incubation times on fungal recovery, is not well documented. This study addressed these gaps using extensive data-based evaluation focused on molds.

Fungal infections diagnosis – Past, present and future

“… Long turn-around-time; in case of yeasts, up to five days, and moulds up to four weeks; Qualification to select the proper medium; Long-delayed targeted treatment; Prone to contaminations; Low sensitivity for candidemia and aspergillosis. [ 35 , 50 , 173 ] Microscopy Visualization of fungal structures; Analysis of shape, tracking of motion, and classification of microorganisms; Visualization of fungal biofilm formation. Does not allow fungal genus or species identification; Similar microscopic appearance of several fungus.…”

“…To improve mould detection by culture, Bao et al [ 50 ] analysed the effect of different culture media and time of incubation of 1,821 moulds (hyaline, dematiaceous, Onygenales and Mucorales) isolated from 1,687 patients. Regarding medium, the inhibitory mould agar (IMA), Sabouraud dextrose agar Emmons (SDAE), and malt-yeast agar (MYA) were tested and results showed that 55.6% of moulds were isolated using IMA, 18.5% using SDAE, and only 3.2% with MYA [ 50 ]. This study showed that SDAE, the often-used culture medium to isolate moulds, did not meet the expectations.…”

“…This study showed that SDAE, the often-used culture medium to isolate moulds, did not meet the expectations. IMA had the best performance, which can be linked to the fact that this medium inhibits bacterial growth [ 50 ]. Concerning incubation time, Mucorales had the fastest growth time, with a growth peak at the 3 rd day.…”

“…Hyaline moulds had the growth peak at 4 th day, and 85.4% of A. fumigatus were mostly isolated after the first week, and 97.3% after two weeks. Contrarily, Histoplasma capsulatum and Trichophyton isolates were isolated during the 4 th week of growth [ 50 ]. Concerning temperature, Tarrand and co-workers [ 51 ] demonstrated that incubation of the 10,062 clinical specimens cultured (sputum, bronchial wash or respiratory lavages) from patients with different pathologies, only 344 (3.4%) showed fungal growth, of Aspergillus species.…”

“…However, this kit can be a useful tool for the diagnosis of infections caused by Fusarium spp., since there is no antigen test for this pathogenic species [ 125 ], and also for histoplasmosis, since Histoplasma spp. can take up to 4 weeks to grow in culture [ 50 , 124 , 126 ]. GM assay can be a useful biomarker for the diagnosis of invasive aspergillosis.…”