Development of a Rapid Diagnostic Method for Sporotrichosis.

Introduction: Sporotrichosis, a prevalent deep fungal infection in clinical settings, currently lacks rapid and accurate diagnostic methodologies. This study explores a novel rapid diagnosis method for sporotrichosis by combining FTA cards and nested PCR with fungal fluorescence staining.

Methods: The study involved skin lesion tissues from 26 patients diagnosed with sporotrichosis (Experimental Group). The Positive Control Group consisted of fungal suspensions from clinical strains of Sporothrix, while the Negative Control Group included fungal solutions of other fungi, namely Trichophyton rubrum, Trichophyton mentagrophyte, and Candida albicans. DNA was extracted from the slurry of skin lesions in the Experimental Group and from fungal suspensions in the Control Group using FTA cards, followed by nested PCR amplification. Subsequently, nested PCR amplification was performed. Histopathological examinations, including HE and fluorescence staining, were conducted on paraffin sections prepared from skin lesion tissues in the Experimental Group.

Results: Among the 26 clinical skin lesion tissues in the Experimental Group, 8 cases showed a specific positive band upon nested PCR amplification, resulting in a positive rate of 30.8%. In the Control Group, the fungal solution of the clinical strain of Sporothrix showed a specific positive band upon nested PCR amplification, while all other fungi Negative Control Group tested negative. Histopathological examination revealed granulomatous inflammatory changes in most samples after HE staining. Fluorescence staining detected spores in 17 cases, resulting in a detection rate of 65.4% (17/26).

Conclusion: The combination of FTA cards with nested PCR method proved to be simple and rapid but demonstrated a relatively low positive rate. Fungal fluorescence staining significantly improved the sensitivity of detecting sporotrichosis in histopathological examinations, thereby improving the speed and efficiency of diagnosis.