Comparison of genotyping methods for Cunninghamella bertholletiae.

BACKGROUND

Invasive fungal infections caused by filamentous fungi of the order Mucorales are serious complications in immunocompromised patients and often associated with fatal outcome. As a member of this order, Cunninghamella bertholletiae is a saprophytic fungus with naturally exhibited high minimum inhibitory concentrations against common antifungal drugs and with the potential for outbreaks in clinical settings.

OBJECTIVES AND METHODS

In a proof-of-principle study, we evaluated the performance of microsatellite markers for the discrimination of thirteen C. bertholletiae isolates from various sources in comparison with a repetitive sequence-based PCR (rep-PCR) and random amplification of polymorphic DNA (RAPD). Based on the higher discriminatory power of the microsatellite PCR with five separate primer pairs (Simpson's index of 1 vs 0 [RAPD] and 0 [rep-PCR]), the novel method was applied to eight additional isolates, including four well-characterised isolates from a cluster of infections in a next step.

RESULTS

In total, microsatellite PCR identified 21 separate genotypes. A probable epidemiological association of the cluster isolates could be demonstrated by microsatellite genotyping.

CONCLUSION

In conclusion, our findings demonstrate the value of microsatellite PCR in genotyping Cunninghamella bertholletiae and its potential for future applications with other species of the order Mucorales.