MLST versus microsatellites for typing Aspergillus fumigatus isolates

In recent years, there has been a clear and growing tendency to use exact typing methods for discrimination between microbial isolates. Exact typing methods that yield an unambiguous typing result offer a number of advantages over conventional methods in the generation of typing data that is reproducible, portable and exchangeable. Two such methods are multi-locus sequence typing (MLST) and microsatellite-based typing. Here I will discuss the basic principles of both methods and compare them from a practical and performance point of view with respect to typing Aspergillus fumigatus isolates. Microsatellites offer the best available typing option by outperforming MLST in terms of speed, throughput, costs and discriminatory power. This latter advantage of microsatellites is a direct consequence of their inherent instability. This (in)stability of individual microsatellite markers and alleles should be taken into account in the interpretation of microsatellite-based typing data.