Genomic analysis of Lactococcus garvieae isolates

Area of Science:

• Microbiology
• Genomics
• Pathogen research

Background:

• Lactococcus garvieae is a significant pathogen affecting both fish and humans.
• Limited understanding exists regarding the variations between local and international L. garvieae isolates.

Purpose of the Study:

• To perform a comparative genomic analysis of local and overseas L. garvieae isolates.
• To investigate phylogenetic and virulence differences between these groups.
• To identify potential transmission pathways.

Main Methods:

• Whole-genome sequencing of 11 local L. garvieae isolates (6 fish, 5 human).
• Multi-locus sequence typing (MLST) for strain characterization.
• Comparative genomic analysis to identify genetic variations and virulence factors.

Main Results:

• Six novel sequence types (STs) were identified in local isolates.
• Genotypic overlap was observed between local and overseas isolates, suggesting fish/food-to-human transmission.
• Virulence genes (internalin, mucus adhesin) were linked to specific genomic clusters (GC2, GC3).
• Local isolates showed a higher prevalence of antibiotic resistance genes (72.72%) compared to overseas isolates (41.18%).

Conclusions:

• This study provides the first evidence of genetic and virulence characteristic variations among local and overseas L. garvieae isolates.
• Phylogenetic specificity of virulence traits was observed.
• Findings suggest potential inter-species transmission and highlight the need for further investigation into L. garvieae epidemiology.