Candida parapsilosis is the second most frequent Candida species isolated from blood cultures. Since 2005, C. parapsilosis has been divided into three distinct species based on genetic traits: Candida parapsilosis, Candida metapsilosis and Candida orthopsilosis. The aim of this study was to develop a rapid real-time PCR assay able to distinguish these closely related species via a melting curve analysis. This identification method was optimized by using reference strains and well-characterized clinical isolates of Candida species. A single set of consensus primers was designed to amplify a 184 bp portion of the SADH gene in order to identify species based on the unique melt profile resulting from DNA sequence variations from each species of the complex. PCR products were detected with SYBR Green fluorescent dye and identification was established by melting curve analysis. For validation of the technique, a total of 116 clinical isolates, phenotypically identified as C. parapsilosis, were tested by real-time PCR and results were further compared with PCR-RFLP patterns of the SADH gene, used as the reference method. The melting curve analysis of amplified DNA could differentiate between C. parapsilosis (83.5 °C), C. metapsilosis (82.9 °C) and C. orthopsilosis (82.1 °C), with a sensitivity and specificity comparable to those of the reference method. One hundred and fourteen C. parapsilosis and two C. orthopsilosis isolates were identified among the clinical isolates. This method provides a simple, rapid and reliable identification of species belonging to the C. parapsilosis complex. This novel approach could be helpful for clinical and epidemiological investigations.

Air quality can be altered by fungal contaminants suspended in the air, forming bioaerosols. Aspergilli section Nidulantes series Versicolores are recurrent in bioaerosols and are mainly responsible for allergies and asthma aggravation. Phylogenetic studies recently identified 12 new species within this series. This study is the first to identify species of Aspergillus series Versicolores in French bioaerosols and to characterize them macroscopically, microscopically and molecularly. Bioaerosols were collected in a cancer treatment center, in contaminated homes and in agricultural environments. A total of 93 isolates were cultured on selective media, observed by optical microscopy and identified by benA amplification before sequencing. The field data (temperature and relative humidity) were statistically tested to explore the ecology of these species. Eight species were identified from bioaerosols: Aspergillus creber and A. jensenii, which represent more than 80% of the isolates, and A. protuberus, A. puulaauensis, A. sydowii, A. tabacinus, A. amoenus and A. fructus. Aspergilli series Versicolores are distributed differently depending on the sampling site and climatic determinants. Aspergillus protuberus was found in bioaerosols collected under significantly lower relative humidity (p = 3.899 × 10⁻⁴). Characterization and repartition of these isolates belonging to the Versicolores series constitute an important step to better assess exposure to fungal bioaerosols.

Cryptococcosis is the third most common cause of invasive fungal infection in solid organ transplant recipients and cryptococcal meningitis (CM) its main clinical presentation. CM outcomes, as well as its clinical features and radiological characteristics, have not yet been considered on a large scale in the context of kidney transplantation (KT). We performed a nationwide retrospective study of adult patients diagnosed with cryptococcosis after KT between 2002 and 2020 across 30 clinical centers in France. We sought to describe overall and graft survival based on whether KT patients with cryptococcosis developed CM or not. Clinical indicators of CNS involvement and brain radiological characteristics were assessed. Eighty-eight cases of cryptococcosis were diagnosed during the study period, with 61 (69.3%) cases of CM. Mortality was high (32.8%) at 12 months (M12) but not significantly different whether or not patients presented with CM. Baseline hyponatremia and at least one neurological symptom were independently associated with CM (p < 0.001). Positive serum cryptococcal antigen at diagnosis was also significantly associated with CM (p < 0.001). On magnetic resonance imaging (MRI), three patterns of brain injury were identified: parenchymal, meningeal, and vascular lesions. Although CM does not affect graft function directly, it entails a grim prognosis.

Molds are ubiquitous biological pollutants in bioaerosols. Among these molds, the genus Aspergillus is found in the majority of indoor air samples, and includes several species with pathogenic and toxigenic properties. Aspergillus species in the series Versicolores remain little known despite recurrence in bioaerosols. In order to investigate their toxicity, we studied 22 isolates of clinical and environmental origin, corresponding to seven different species of the series Versicolores. Spore suspensions and ethyl acetate extracts prepared from fungal isolates were subjected to oxidative potential measurement using the dithiothreitol (DTT) test and cell survival measurement. The DTT tests showed that all species of the series Versicolores had an oxidative potential, either by their spores (especially for Aspergillus jensenii) or by the extracts (especially from Aspergillus amoenus). Measurements of cell survival of A549 and HaCaT cell lines showed that only the spore suspension containing 10⁵ spores/mL of Aspergillus jensenii caused a significant decrease in survival after 72 h of exposure. The same tests performed with mixtures of 10⁵ spores/mL showed a potentiation of the cytotoxic effect, with a significant decrease in cell survival for mixtures containing spores of two species (on A549 cells, p = 0.05 and HaCaT cells, p = 0.001) or three different species (on HaCaT cells, p = 0.05). Cell survival assays after 72 h of exposure to the fungal extracts showed that Aspergillus puulaauensis extract was the most cytotoxic (IC50 < 25 µg/mL), while Aspergillus fructus caused no significant decrease in cell survival.