Complete Genome Sequences of Three Fish-Associated Streptococcus agalactiae Isolates

Area of Science:

• Aquatic microbiology
• Fish disease research
• Genomics

Background:

• Group B Streptococcus (GBS), also known as Streptococcus agalactiae, is a significant pathogen affecting both humans and animals.
• Streptococcosis is a serious bacterial disease impacting farmed fish populations globally.
• Tilapia (Oreochromis niloticus) aquaculture is a major global industry, making fish health a critical concern.

Purpose of the Study:

• To perform whole-genome sequencing of Streptococcus agalactiae serotype Ib isolates from diseased tilapia.
• To characterize the genetic makeup of GBS strains originating from different geographical locations within aquaculture settings.

Main Methods:

• Whole-genome sequencing of three GBS serotype Ib isolates.
• Bacterial isolation from the brains of tilapia exhibiting streptococcosis symptoms.
• Geographical sourcing of isolates from Honduras, Costa Rica, and the United States.

Main Results:

• Complete genome sequences for three Streptococcus agalactiae serotype Ib strains were obtained.
• Isolates were identified in tilapia from aquaculture farms in Honduras, Costa Rica, and the United States.
• The bacteria were associated with fish displaying clinical signs of streptococcosis.

Conclusions:

• The study provides valuable genomic data for GBS serotype Ib strains affecting tilapia.
• This information can aid in developing targeted strategies for streptococcosis prevention and control in aquaculture.
• Understanding the genetic diversity of GBS in farmed fish is essential for aquatic animal health surveillance.