Lactococcus garvieae: Where Is It From? A First Approach to Explore the Evolutionary History of This Emerging Pathogen

Abstract

The population structure and diversity of Lactococcus garvieae, an emerging pathogen of increasing clinical significance, was determined at both gene and genome level. Selected lactococcal isolates of various origins were analyzed by a multi locus sequence typing (MLST). This gene-based analysis was compared to genomic characteristics, estimated through the complete genome sequences available in database. The MLST identified two branches containing the majority of the strains and two branches bearing one strain each. One strain was particularly differentiated from the other L. garvieae strains, showing a significant genetic distance. The genomic characteristics, correlated to the MLST-based phylogeny, indicated that this “separated strain” appeared first and could be considered the evolutionary intermediate between Lactococcus lactis and L. garvieae main clusters. A preliminary genome analysis of L. garvieae indicated a pan-genome constituted of about 4100 genes, which included 1341 core genes and 2760 genes belonging to the dispensable genome. A total of 1491 Clusters of Orthologous Genes (COGs) were found to be specific to the 11 L. garvieae genomes, with the genome of the “separated strain” showing the highest presence of unique genes.

Afebrile Multi-valve Infective Endocarditis Caused by <i>Lactococcus garvieae</i>: A Case Report and Literature Review

“…Due to improved molecular methodologies, these strains were revealed to originate not only in fish and dairy products, but also in meat products, vegetables, and cereals (29). Along with this spread, L. garvieae has also been identified as a clinical pathogen in patients with infective endocarditis.…”

A Virulent Phage Infecting Lactococcus garvieae, with Homology to Lactococcus lactis Phages

“…Five milliliters of each environmental sample (for the solid compost soil, 5 g was resuspended in 5 ml of sterile water) was added to 5 ml of double-strength GM17 supplemented with 10 mM CaCl 2 and inoculated with 100 l of an overnight culture of an L. garvieae strain. Nineteen representative strains of previously studied L. garvieae (8) were used for lytic phage isolation. The mixtures were incubated overnight at 30°C.…”

“…These studies also revealed that L. garvieae is related to Lactococcus lactis, a nonpathogenic bacterium used for the manufacture of several fermented dairy products (9). Divergent genomic lineages were observed, with some ecotypes representing evolutionary intermediates between L. lactis and L. garvieae (8). The presence of insertion sequences (ISs) was also highly variable among L. garvieae strains (10).…”

“…The population structure and diversity of L. garvieae strains have been studied using comparative genome analysis, which led to the development of a multilocus sequence type (MLST) scheme to identify specific strains (8). These studies also revealed that L. garvieae is related to Lactococcus lactis, a nonpathogenic bacterium used for the manufacture of several fermented dairy products (9).…”

Microbiome analysis – from technical advances to biological relevance

“…However, unlike shotgun sequencing, PICRUSt does not reflect strain diversity such as that which may be observed in numerous bacterial species, including pathobiont strains [46]. It also cannot yet impute viral or eukaryotic organism function.…”