Dear Citizens of Little Rock,
I make it a priority to keep you up to date on the latest infectious disease news. Here is a infectious disease gene sequencing tool that has been developed, and is starting to become more popular.
Multi Locus Sequence Typing (MLST) is a DNA based typing system developed for the global identification and tracking of pathogenic bacteria (Johnson, Arduino, Stine, et al., 2007). This identification tool was developed in an attempt to combine identification, typing, and statistical information into one centralized, global database (Weihong et al., 2004). Multi Locus Sequence Typing is a procedure that is utilized to identify isolates of varying pathogenic bacterial species utilizing internal fragments of nucleotides, loci; the loci are commonly referred to as the housekeeping genes of DNA (Maiden, Bygraves, Feil, et al., 1998).
MLST contains an automated DNA sequencing unit that analyzes and sequences between 450 and 500 base pair fragments from each gene. Breaking the process down step by step, there are three distinct work-flow stages (steps) that are involved, and they are: data collection, data analysis, and multi locus sequencing analysis. In the data collection step, the pathogenic bacteria’s definitive identification, as well as any and all variations to the genetic makeup of the pathogenic bacteria, are gathered through the determination of the nucleotide sequence of each gene fragment. Step two, data analysis, involves assigning allelic numbers to the allele sequences identified in step one. If, during step one, a new allelic sequence or sequence type is determined, step one is repeated for verification. Upon verification, the database is updated with a new table representing the genetic mutation of the pathogenic bacteria. Finally, during the multi locus sequencing analysis, epidemiologists and phylogeneticists are able to analyze the relationships found during the isolation phase, and compare allelic profiles and different clonal complexes to track and identify the genetic change in the pathogenic bacteria (Johnson, Arduino, Stine, et al., 2007; Weihong et al., 2004; Maiden, Bygraves, Feil, et al., 1998; Francis, Harrington, Carroll, & Bishai, 2007).
MLST possesses advantages over other DNA typing and sequencing tools. MLST has a high degree of specificity, contributing to this tool being unambiguous. The MLST process also contains a high degree of discrimination, allowing for the identification of mutations and genetic changes that accumulate at a slow rate in bacterial pathogens. The process is also reproducible and scalable, allowing the sequencing type determination and other relevant information to be shared electronically (Francis, Harrington, Carroll, & Bishai, 2007). Additionally, the information can be combined with bioinformatics and population genetics, and can be used to trace the evolutionary progress and relationships of identified pathogenic bacteria within a population (Maiden, Bygraves, Feil, et al., 1998).
The cost of the MLST tool is one of the disadvantages. The costs are associated with the MLST tool itself, as well as the technological infrastructure needed to support it. The amount of data produced through sequencing and identification is astronomical, and the computers must be able to simultaneously gather the data, store the data, and run bioinformatics analysis programs, file management programs, and analysis programs while the sequencing and identification is being performed (Johnson, Arduino, Stine, et al., 2007; Weihong et al., 2004; Maiden, Bygraves, Feil, et al., 1998). In addition, MLST is intolerant of DNA sequencing errors, which if not identified by the researcher or scientist performing the analysis, can lead to data error and mistyping.