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Virulence of Paracoccidioides brasiliensis isolates can be correlated to groups defined by random amplified
E E Molinari-Madlum1, M S Felipe, C M Soares
1Laboratório de Imunopatologia, IPTSP, Universidade Federal de Goiás, Goiânia, Brazil.
Abstract:
Fifteen Paracoccidioides brasiliensis isolates were discriminated by the RAPD analysis into two groups with only 17% of genomic identity. The ability of P. brasiliensis isolates to invade tissues was studied in an experimental model using susceptible B10.A mice. The analysis was performed according to the severity of the lesions including the number and size of the granuloma, the number and dissemination of fungi to different organs. The isolates from two RAPD groups demonstrated a marked difference in their virulence patterns for B10.A mice. The isolates Pb S, 662, Bt and 166 (group I) elicited localized infection restricted to the liver showing compact epithelioid granuloma with few fungi in the early post-infection period (slightly virulent). On the other hand the isolates Pb 01 and 7455 (group II) elicited a disseminated infection with a mixed suppurative and looser granulomatous inflammation, showing extensive areas of necrosis and large numbers of viable fungal cells (highly virulent). These results are strong evidence for correlation between RAPD patterns and the virulence degree of P. brasiliensis.
Insights
Random Amplified Polymorphic DNA (RAPD) analysis revealed two distinct groups of Paracoccidioides brasiliensis isolates. These groups exhibited significant differences in virulence, correlating with their genetic profiles.
Area of Science:
- Mycology
- Infectious Diseases
- Genetics
Background:
- Paracoccidioides brasiliensis is a fungal pathogen causing paracoccidioidomycosis.
- Understanding isolate variability is crucial for disease management.
Purpose of the Study:
- To investigate the correlation between genetic profiles and virulence of Paracoccidioides brasiliensis isolates.
- To discriminate P. brasiliensis isolates using molecular techniques.
Main Methods:
- Random Amplified Polymorphic DNA (RAPD) analysis was used to group 15 P. brasiliensis isolates.
- Virulence was assessed in a B10.A mouse model by evaluating lesion severity, granuloma formation, and fungal dissemination.
Main Results:
- RAPD analysis delineated two distinct genetic groups with only 17% genomic identity.
- Isolates from Group I caused localized liver infections (low virulence).
- Isolates from Group II induced disseminated infections with necrosis and high fungal loads (high virulence).
Conclusions:
- RAPD patterns correlate significantly with the virulence of Paracoccidioides brasiliensis isolates.
- Genetic typing can predict the pathogenic potential of P. brasiliensis strains.