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Title: Determining If Phylogenetic Relatedness of Listeria Monocytogenes Isolates Corresponds to Persistence in Poultry Processing Plants Using Whole-Genome Sequencing

item HUDSON, L - University Of Georgia
item Berrang, Mark
item Meinersmann, Richard - Rick
item DENG, X - University Of Georgia
item HARRISON, M - University Of Georgia

Submitted to: International Association for Food Protection Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction: Controlling Listeria monocytogenes on ready-to-eat meat and poultry products and in food processing facilities is challenging. Surveys have found that some L. monocytogenes types are more persistent in processing facilities than others, but the reason is unknown. It is possible persistent strains vary genetically from transient ones, giving them an advantage that aids in attachment to surfaces and biofilm formation in processing facilities. Purpose: The goal of the study was to use whole genome sequencing (WGS) to determine phylogenetic relationships among L. monocytogenes strains and to determine if these relationships correspond to persistence. Methods: In two previous longitudinal studies of L. monocytogenes in poultry processing plants, isolates were collected, separated into discreet subtypes by sequencing of actA gene, and identified as either transient or persistent. In the present study, 170 genomes were extracted, sequenced on the Illumina MiSeq platform, de novo assembled, and annotated. Genomes with acceptable assembly quality scores (160 isolates total) were analyzed to determine phylogenetic relatedness. Repeat sequences, phage sequences, and recombination regions were trimmed out. Core-genome alignment, SNP calling, and phylogenetic tree construction were performed using Harvest suite including Parsnp. Results: Clades present on the constructed phylogenetic tree follow closely with subtypes determined via sequencing of actA gene in the original studies. No clear phylogenic relationship trends between persistent and transient subtypes analyzed could be determined. Raw sequence data and contigs will be added to the appropriate publically accessible GenBank database to be available for further analysis. Significance: Additional analysis is needed to identify genetic factors that may be involved or interact with regulation of genes that influence ability of some strains to colonize and survive on food and non-food contact surfaces, while others are less likely to do so. In addition, this data shows WGS, along with phylogenetic analysis, is a viable option for subtyping L. monocytogenes isolates.