Comparative genomics and evolutionary analysis of Lactococcus garvieae isolated from human endocarditis

Abstract

Lactococcus garvieae is a well-known pathogen of fish, but is rarely involved in infections in humans and other mammals. In humans, the main clinical manifestation of L. garvieae infections is endocarditis usually related to the ingestion of contaminated food, such as undercooked fish and shellfish. This study presents the first complete genomic sequence of a clinical L. garvieae strain isolated from a patient with endocarditis and its comparative analysis with other genomes. This human isolate contains a circular chromosome of 2 099 060 bp and one plasmid of 50 557 bp. In comparison with other fully sequenced L. garvieae strains, the chromosomal DNA of L. garvieae Lg-Granada carries a low proportion of insertion sequence elements and a higher number of putative prophages. Our results show that, in general, L. garvieae is a highly recombinogenic species with an open pangenome in which almost 30 % of its genome has undergone horizontal transfers. Within the genus Lactococcus, L. lactis is the main donor of genetic components to L. garvieae but, taking Lg-Granada as a representative, this bacterium tends to import more genes from Bacilli taxa than from other Lactococcus species.

Comparative Genomic Analyses of Lactococcus garvieae Isolated from Bovine Mastitis in China

“…Although L. garvieae was first isolated as a causative agent of bovine mastitis ( 27 ), most reports have focused on epidemiology of isolates from fish or humans. In addition, many studies used sequencing to investigate genotypic characteristics of L. garvieae isolates ( 8 , 28 – 40 ). Therefore, we collected 39 L. garvieae isolates from bovine mastitis in China and conducted comparative genome sequence analyses.…”

“… Lactococcus garvieae is a zoonotic pathogen reported to cause infections in fish ( 4 ) and humans ( 5 – 8 ). It is also considered a minor pathogen for bovine mastitis, with transmission attributed to environmental reservoirs ( 2 ).…”

Comparative genomic analyses of Lactococcus garvieae isolated from bovine mastitis in China

“…Although L. garvieae was first isolated as a causative agent of bovine mastitis ( 27 ), most reports have focused more on the epidemiology of fish and human cases. In addition, many studies used sequencing to investigate genotypic characteristics of L. garvieae isolates ( 8, 28–40 ). Therefore, we collected 39 L. garvieae isolates from bovine mastitis in China and conducted comparative genome sequence analysis of L. garvieae .…”

“…Lactococcus garvieae is a zoonotic pathogen reported to cause infections in fish ( 4 ) and humans ( 5–8 ). It is also considered a minor pathogen for bovine mastitis, with transmission attributed to environmental reservoirs ( 2 ).…”

Garvicins AG1 and AG2: Two Novel Class IId Bacteriocins of Lactococcus garvieae Lg-Granada

“…garvieae Lg-Granada was originally isolated from the blood of a patient with endocarditis [20]. Although this strain does not exhibit bacteriocinogenic activity, sequencing of its plasmid pLG50 revealed the presence of two sets of genes (orf46-47 and orf48-49), each one encoding a novel putative bacteriocin (orf46 and orf48), and their respective immunity proteins (orf47 and orf49) [35]. Because of the potential of garvicins as future antimicrobial agents in clinical and food settings, the objectives of this work were, first, to elucidate whether the bacteriocin-like peptides encoded by orf46 and orf48 actually displayed antimicrobial activity and, if so, to determine their respective antimicrobial spectra; and second, to assess the fermentation capacity of mannose of the sensitive indicator strains in order to determine whether the mannose phosphotransferase (Man-PTS) transporter system may be a possible cellular target for the recognition of these bacteriocins.…”