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Clinical and Molecular Characterization of Feline Sporotrichosis in the Brazilian Amazon: PCR-Based Identification of Sporothrix brasiliensis

Summary

This research studied a fungal disease called sporotrichosis that affects cats in the Brazilian Amazon and can spread to humans. Most infected cats were young males that roamed freely outdoors and had skin lesions on their faces and paws. Researchers tested different laboratory methods to identify the fungus and found that a specific technique extracted DNA best. They confirmed that Sporothrix brasiliensis was the cause and tested how well common antifungal medications work against it, finding that some drugs work better than others.

Background

Sporotrichosis is a zoonotic fungal infection with increasing incidence in the Brazilian Amazon, primarily affecting domestic cats and posing risks to human health. Cats play a central role in transmission through direct contact via scratches, bites, and lesions. In Manaus, sporotrichosis cases have quadrupled in animals and doubled in humans between 2020-2023, necessitating improved diagnostic approaches.

Objective

This study characterized the clinical and epidemiological profiles of 29 feline sporotrichosis cases in Manaus and optimized molecular diagnostic methods for Sporothrix species identification. The objectives included evaluating clinical characteristics, comparing DNA extraction methods, assessing PCR primer efficiency, evaluating PCR-RFLP discriminatory power, and determining antifungal susceptibility profiles of regional isolates.

Results

Most affected cats were young (86.2% aged 1-3 years), male (82.7%), and free-roaming or semi-indoor (44.8% each), with cutaneous lesions predominantly on the nasal planum (23.3%), face (18.6%), and paws (16.3%). Phenol-chloroform DNA extraction yielded the highest DNA concentration and purity. ITS1-ITS4 primers showed superior sensitivity for PCR detection. Phylogenetic analysis confirmed all four sequenced isolates as Sporothrix brasiliensis with MIC values of 0.25 µg/mL for ketoconazole and 64 µg/mL for fluconazole.

Conclusion

This study confirmed S. brasiliensis as the predominant species causing feline sporotrichosis in the Brazilian Amazon. Optimized molecular diagnostic approaches, particularly phenol-chloroform DNA extraction and ITS1-ITS4 PCR primers, can standardize species identification and support epidemiological surveillance. These findings provide clinical, molecular, and therapeutic information essential for diagnosis, surveillance, and control of sporotrichosis in endemic regions.
  • Published in:Animals (Basel),
  • Study Type:Cross-sectional observational study with laboratory analysis,
  • Source: PMID: 40805106
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