An atypical Paracoccidioides brasiliensis clinical isolate based on multiple gene analysis

Area of Science:

• Medical Mycology
• Molecular Biology
• Genetics

Background:

• Paracoccidioides brasiliensis is a fungus causing paracoccidioidomycosis, a systemic mycosis endemic in Latin America.
• Diagnostic methods like immunodiffusion and PCR targeting the gp43 gene are crucial for identifying P. brasiliensis.
• Atypical isolates can pose diagnostic challenges and may represent distinct evolutionary lineages.

Observation:

• An atypical P. brasiliensis (IFM54648) isolate from Brazil was undetectable by standard paracoccidioidomycosis diagnostic tests.
• Mycological characteristics of IFM54648 were similar to typical P. brasiliensis strains.
• Sequencing of 8 genes, including gp43, ribosomal RNA, and metabolic enzyme genes, was performed.

Findings:

• Gene sequence identities between IFM54648 and the atypical isolate Pb01 were high (98.9-100%).
• Identities were lower (<98%) when comparing IFM54648 to typical P. brasiliensis isolates.
• Phylogenetic analysis based on gp43 sequences revealed IFM54648 clustered with Pb01, distinct from other isolates.

Implications:

• The IFM54648 isolate likely represents a genetically distinct lineage, similar to the previously identified atypical isolate Pb01.
• This genetic divergence may have implications for diagnostic test efficacy and understanding P. brasiliensis epidemiology.
• Further research into the genetic diversity of P. brasiliensis is warranted to improve diagnostics and treatment strategies.