Genomic Analysis of Prophages Recovered from <i>Listeria monocytogenes</i> Lysogens Found in Seafood and Seafood-Related Environment

• Main Authors: Hue Thi Kim Vu, Matthew J. Stasiewicz, Soottawat Benjakul, Kitiya Vongkamjan
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Microorganisms
• Subjects: comparative genomic analysis; <i>L. monocytogenes</i> lysogen; <i>Listeria</i> prophage; phage sequencing analysis
• Online Access: https://www.mdpi.com/2076-2607/9/7/1354

A prophage is a phage-related sequence that is integrated into a bacterial chromosome. Prophages play an important role in bacterial evolution, survival, and persistence. To understand the impact of <i>Listeria</i> prophages on their host genome organizations, this work sequenced two <i>L. monocytogenes</i> strains (134LM and 036LM), previously identified as lysogens by mitomycin C induction. Draft genomes were generated with assembly sizes of 2,953,877 bp and 3,000,399 bp. One intact prophage (39,532 bp) was inserted into the <i>comK</i> gene of the 134LM genome. Two intact prophages (48,684 bp and 39,488 bp) were inserted in tRNA-Lys and elongation-factor genes of the 036LM genome. The findings confirmed the presence of three corresponding induced phages previously obtained by mitomycin C induction. Comparative genomic analysis of three prophages obtained in the newly sequenced lysogens with 61 prophages found in <i>L. monocytogenes</i> genomes, available in public databases, identified six major clusters using whole genome-based phylogenetic analysis. The results of the comparative genomic analysis of the prophage sequences provides knowledge about the diversity of <i>Listeria</i> prophages and their distribution among <i>Listeria</i> genomes in diverse environments, including different sources or geographical regions. In addition, the prophage sequences and their insertion sites contribute to the genomic diversity of <i>L. monocytogenes</i> genomes. These data of prophage sequences, prophage insertion sites, and prophage sequence comparisons, together with ANIb confirmation, could be useful for <i>L. monocytogenes</i> classification by prophages. One potential development could be refinement of prophage typing tools for monitoring or surveillance of <i>L. monocytogenes</i> contamination and transmission.