Gabriella Tocci

Background: Trichophyton indotineae, a new emerging pathogen according to the WHO, is known to cause severe forms of tinea. Given that traditional identification methods rely on morphological characteristics, and the morphological distinctions among T. indotineae, T. mentagrophytes, and T. interdigitale are minimal, the adoption of alternative diagnostic techniques, such as RT-PCR or gene sequencing, has become critically important to prevent misidentification. The purpose of this study was firstly to analyze the local epidemiology of dermatophytes isolated and secondly to investigate the presence of T. indotineae among the isolated strains. Methods: Between January 2021 and June 2024, 1096 samples of skin adnexa were analysed. The isolated strains belonging to the genus Trichophyton were submitted to molecular identification by ITS sequencing, and T. indotineae strains were subjected to squalene epoxidase (SQLE) sequencing analysis. Results: Trichophyton rubrum and Trichophyton interdigitale appear to be the most prevalent pathogenic species. Molecular identification reveals four T. indotineae strains (4/87; 4.61%) from Asian patients, which were also characterized by gene mutations associated with terbinafine resistance. Conclusions: This study has made it clear that there is a need to implement basic mycological diagnostics with molecular methods to avoid misidentifications, ensure the correct identification, and evaluate the presence of mutations associated with antifungal drug resistance.

The analytical performance of the new Aspergillus Galactomannan Ag VirCLIA^® mono-test (Vircell S.L.) was compared to the Platelia™ Aspergillus Ag ELISA assay (Bio-Rad). Prospective serum and bronchoalveolar lavage (BAL) samples from patients at risk of invasive aspergillosis (IA) were tested using both the Aspergillus Galactomannan Ag VirCLIA^® mono-test and the Platelia™ Aspergillus Ag ELISA assay. Concordance, sensitivity, specificity, and positive and negative predictive values were calculated using the manufacturer-recommended cutoff levels. Receiver operating characteristic (ROC) analysis and the Youden index were performed to determine the optimal cutoff. A total of 187 serum samples and 73 BAL samples were analyzed with both assays. The concordance between the Aspergillus Galactomannan Ag VirCLIA^® mono-test and the Platelia™ Aspergillus Ag ELISA assay was 87.8%, with a Cohen’s kappa of 0.75. The sensitivity and specificity of the Aspergillus Galactomannan Ag VirCLIA^® mono-test were 78.6% and 96.2%, respectively, with positive and negative predictive values of 94.8% and 83.3%. The ROC curve for the Aspergillus Galactomannan Ag VirCLIA^® mono-test demonstrated an area under the curve (AUC) of 0.87, and the Youden index at the manufacturer’s established cutoff was 0.73. This new Aspergillus Galactomannan Ag VirCLIA^® mono-test exhibited adequate analytical and clinical performance, showing good correlation with the Platelia™ Aspergillus Ag ELISA assay. The single-sample, semi-automated test is user-friendly, allowing small laboratories to perform the test on demand without the need for batch evaluations, providing a useful solution for timely diagnostic support for clinicians.