ABSTRACTThe genusListeriais ubiquitous in the environment and includes the globally important food-borne pathogenListeria monocytogenes. While the genomic diversity ofListeriahas been well studied, considerably less is known about the genomic and morphological diversity ofListeriabacteriophages. In this study, we sequenced and analyzed the genomes of 14Listeriaphages isolated mostly from New York dairy farm environments as well as one relatedEnterococcus faecalisphage to obtain information on genome characteristics and diversity. We also examined 12 of the phages by electron microscopy to characterize their morphology. TheseListeriaphages, based on gene orthology and morphology, together with previously sequencedListeriaphages could be classified into five orthoclusters, including one novel orthocluster. One orthocluster (orthocluster I) consists of large-genome (∼135-kb) myoviruses belonging to the genus “Twort-like viruses,” three orthoclusters (orthoclusters II to IV) contain small-genome (36- to 43-kb) siphoviruses with icosahedral heads, and the novel orthocluster V contains medium-sized-genome (∼66-kb) siphoviruses with elongated heads. A novel orthocluster (orthocluster VI) ofE. faecalisphages, with medium-sized genomes (∼56 kb), was identified, which grouped together and shares morphological features with the novelListeriaphage orthocluster V. This new group of phages (i.e., orthoclusters V and VI) is composed of putative lytic phages that may prove to be useful in phage-based applications for biocontrol, detection, and therapeutic purposes.
Efficiency and Competitiveness of the Small New York Dairy Farm
