Released on March 9, 2023
Back to episode listFeatured Guests:
In this session, we explore the concept of multi-locus sequence typing (MLST) in bacterial population genetics with insights from our esteemed guests.
MLST is a method utilized to define bacterial strains based on partial sequences that can be up to 500 base pairs long. This method identifies differences between loci for each strain and assigns an allele number, providing identical sequences with the same numbers. The cumulative sequence number generated is known as the sequence type (SST), which is used for unique identification.
MLST has transformed the study of bacterial genetics by enabling digital storage and comparison of epidemiological databases. Its applications are particularly valuable in:
Although there are methods with higher resolution, such as Pulse Field Gel Electrophoresis (PFGE), MLST remains widely used due to its versatility.
While MLST has its limitations, continued advancements in population genetics research seek to improve upon these. The development of the Eburst program is notable; it uses a circular model instead of the traditional dendrogram tree structure to effectively visualize MLST data and understand clonal expansions.
A key point Ed and Natacha make is that the original MLST schemes may not have chosen the most optimal genes for all bacterial species due to the limited availability of genome sequencing at the time.
Ed Feil elaborates on bacterial population structures, emphasizing their inconsistency. Some organisms adhere to patterns, while others exhibit extensive allele shuffling. Nevertheless, the presence of bacterial clones has persisted over time.
Natacha Couto points out that despite its flaws, MLST has established a lasting nomenclature for bacterial lineages or clones.
While many reference laboratories have advanced to genomics, MLST remains in use by some. The pipeline remains consistent across organisms, ultimately proving efficient. Our discussion emphasizes understanding the limitations of MLST and recognizing the potential for further research in bacterial population genetics.
The hosts conclude by expressing gratitude to the guests and hinting at more intriguing topics in future episodes. Understanding the intricacies of methods like MLST is crucial for advancing the field of bacterial genetics.