Biomaterial Database

Proof-of-concept study for successful inter-laboratory comparison of MLVA results. 2013

J T Larsson, and M Torpdahl, and , and E Møller Nielsen

Statens Serum Institut, Copenhagen, Denmark.

Multiple-locus variable-number of tandem repeats analysis (MLVA) is widely used for typing of pathogens. Methods such as MLVA based on determining DNA fragment size by the use of capillary electrophoresis have an inherent problem as a considerable offset between measured and real (sequenced) lengths is commonly observed. This discrepancy arises from variation within the laboratory set-up used for fragment analysis. To obtain comparable results between laboratories using different set-ups, some form of calibration is a necessity. A simple approach is to use a set of calibration strains with known allele sizes and determine what compensation factors need to be applied under the chosen set-up conditions in order to obtain the correct allele sizes. We present here a proof-of-concept study showing that using such a set of calibration strains makes inter-laboratory comparison possible. In this study, 20 international laboratories analysed 15 test strains using a five-locus Salmonella enterica serovar Typhimurium MLVA scheme. When using compensation factors derived from a calibration set of 33 isolates, 99.4% (1,461/1,470) of the MLVA alleles of the test strains were assigned correctly, compared with 64.8% (952/1,470) without any compensation. After final analysis, 97.3% (286/294) of the test strains were assigned correct MLVA profiles. We therefore recommend this concept for obtaining comparable MLVA results.

UI	MeSH Term	Description	Entries
D005838	Genotype	The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.	Genogroup,Genogroups,Genotypes
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000483	Alleles	Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.	Allelomorphs,Allele,Allelomorph
D012486	Salmonella typhimurium	A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.	Salmonella typhimurium LT2
D017410	Practice Guidelines as Topic	Works about directions or principles presenting current or future rules of policy for assisting health care practitioners in patient care decisions regarding diagnosis, therapy, or related clinical circumstances. The guidelines may be developed by government agencies at any level, institutions, professional societies, governing boards, or by the convening of expert panels. The guidelines form a basis for the evaluation of all aspects of health care and delivery.	Clinical Guidelines as Topic,Best Practices,Best Practice
D058885	Multilocus Sequence Typing	Direct nucleotide sequencing of gene fragments from multiple housekeeping genes for the purpose of phylogenetic analysis, organism identification, and typing of species, strain, serovar, or other distinguishable phylogenetic level.	Multilocus Sequence Analysis,Analyses, Multilocus Sequence,Analysis, Multilocus Sequence,Multilocus Sequence Analyses,Sequence Analyses, Multilocus,Sequence Analysis, Multilocus,Sequence Typing, Multilocus,Typing, Multilocus Sequence
D019411	Clinical Laboratory Techniques	Techniques used to carry out clinical investigative procedures in the diagnosis and therapy of disease.	Clinical Laboratory Test,Clinical Laboratory Testing,Clinical Laboratory Diagnoses,Clinical Laboratory Testings,Clinical Laboratory Tests,Diagnoses and Laboratory Examinations,Diagnosis, Laboratory,Laboratory Diagnosis,Laboratory Examinations and Diagnoses,Laboratory Techniques, Clinical,Clinical Laboratory Technique,Diagnose, Clinical Laboratory,Laboratory Diagnoses,Laboratory Technique, Clinical,Laboratory Test, Clinical,Laboratory Testing, Clinical,Technique, Clinical Laboratory,Test, Clinical Laboratory,Testing, Clinical Laboratory
D019779	Salmonella enterica	A subgenus of Salmonella containing several medically important serotypes. The habitat for the majority of strains is warm-blooded animals.
D020080	Tandem Repeat Sequences	Copies of DNA sequences which lie adjacent to each other in the same orientation (direct tandem repeats) or in the opposite direction to each other (INVERTED TANDEM REPEATS).	Direct Tandem Repeats,Tandem Repeat,Tandem Repeats,Direct Tandem Repeat,Repeat Sequence, Tandem,Repeat Sequences, Tandem,Repeat, Direct Tandem,Repeat, Tandem,Repeats, Direct Tandem,Repeats, Tandem,Sequence, Tandem Repeat,Sequences, Tandem Repeat,Tandem Repeat Sequence,Tandem Repeat, Direct,Tandem Repeats, Direct