Genotyping of dairy Bacillus licheniformis isolates by high resolution melt analysis of multiple variable number tandem repeat loci

Dhakal, Rajat, Chauhan, Kanika, Seale, R. Brent, Deeth, Hilton C., Pillidge, Christopher J., Powell, Ian B., Craven, Heather and Turner, Mark S. (2013) Genotyping of dairy Bacillus licheniformis isolates by high resolution melt analysis of multiple variable number tandem repeat loci. Food Microbiology, 34 2: 344-351. doi:10.1016/j.fm.2013.01.006


Author Dhakal, Rajat
Chauhan, Kanika
Seale, R. Brent
Deeth, Hilton C.
Pillidge, Christopher J.
Powell, Ian B.
Craven, Heather
Turner, Mark S.
Title Genotyping of dairy Bacillus licheniformis isolates by high resolution melt analysis of multiple variable number tandem repeat loci
Formatted title
Genotyping of dairy Bacillus licheniformis isolates by high resolution melt analysis of multiple variable number tandem repeat loci
Journal name Food Microbiology   Check publisher's open access policy
ISSN 0740-0020
1095-9998
Publication date 2013-06
Sub-type Article (original research)
DOI 10.1016/j.fm.2013.01.006
Volume 34
Issue 2
Start page 344
End page 351
Total pages 8
Place of publication London, United Kingdom
Publisher Academic Press
Collection year 2014
Language eng
Formatted abstract
In dairy foods, the sporeformer Bacillus licheniformis can be the cause of spoilage or specification compliance issues. Currently used methods for genotyping B. licheniformis have limited discrimination with only 2 or 3 different subgroups being identified. Here, we have developed a multi-locus variable number tandem repeat analysis (MLVA) method and combined it with high resolution melt analysis (MLV-HRMA) for genotyping B. licheniformis. Five repetitive loci were identified and used as markers for genotyping 52 isolates from two milk powder processing plants and retail samples. Nineteen genotypes could be identified using both MLVA and MLV-HRMA leading to Hunter-Gaston discrimination indices (D-value) of 0.93 each. It was found that all 5 MLVA loci were stable following 10 days of sub-culturing of 8 representative isolates. All isolates were also genotyped using previously used methods including randomly amplified polymorphic DNA-PCR (RAPD) and partial rpoB sequencing. Five different RAPD profiles and 5 different partial rpoB sequence types were identified resulting in corresponding D-values of 0.6 and 0.46, respectively. Analysis of the genotypes from dairy samples revealed that dairy B. licheniformis isolates are more heterogeneous than previously thought and that this new method can potentially allow for more discriminatory tracking and monitoring of specific genotypes.
Keyword Genotyping
Dairy
Bacillus licheniformis
MLVA
HRMA
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Agriculture and Food Sciences
Queensland Alliance for Agriculture and Food Innovation
Official 2014 Collection
 
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