MLST

MLST or Multi Locus Sequence Typing is a technique in molecular biology used to characterize isolates of microbial species using the sequences of internal fragments of multiple housekeeping genes.

Overview

MLST was first proposed in 1998 by Maiden MC, et al. as a highly discriminatory method of typing bacterial isolates. It has since been applied to a wide range of microorganisms including bacteria, fungi and parasites. The technique is based on the analysis of the sequence of internal fragments of (usually) seven housekeeping genes. Each different sequence within a species is assigned a distinct allele number and the combination of alleles at the seven loci defines the sequence type or ST.

Procedure

The procedure of MLST involves the following steps:

1. DNA is extracted from the microorganism.
2. Specific regions of the housekeeping genes are amplified by PCR.
3. The PCR products are sequenced.
4. The sequences are compared with those in a database and an allele number is assigned to each one.
5. The combination of the seven allele numbers defines the ST.

Applications

MLST has been used in various applications such as:

1. Epidemiology: MLST can be used to track the spread of particular strains of microorganisms.
2. Population genetics: MLST can be used to study the population structure and evolutionary history of a species.
3. Microbial forensics: MLST can be used to identify the source of a particular strain in an outbreak.

Advantages and Disadvantages

MLST has several advantages over other typing methods. It is highly discriminatory, reproducible and the data can be easily compared between different laboratories. However, it is also more expensive and time-consuming than other methods.

See also

• Molecular biology
• Microbiology
• Epidemiology
• Population genetics
• Microbial forensics

References

MLST Resources
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