Molecular typing of Streptococcus agalactiae isolates from fish
O Olivares-Fuster1, P H Klesius, J Evans
1Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, AL 36849, USA.
Journal of Fish Diseases
|March 21, 2008
Summary
Genetic variability in fish-associated Streptococcus agalactiae was assessed using intergenic spacer region (ISR) single-stranded conformation polymorphism (SSCP) and amplified fragment length polymorphism (AFLP). AFLP provided higher resolution, revealing distinct genotypes correlated with geographical origin.
Area of Science:
- Microbiology
- Genetics
- Aquatic Animal Health
Background:
- Streptococcus agalactiae is an emerging pathogen in fish.
- Understanding the genetic diversity of fish-associated S. agalactiae is crucial for disease control.
Purpose of the Study:
- To characterize the genetic variability of Streptococcus agalactiae isolates from fish.
- To evaluate the effectiveness of ISR-SSCP and AFLP for differentiating these isolates.
- To explore the correlation between genetic profiles and geographical origin.
Main Methods:
- Analysis of 46 S. agalactiae isolates from various fish species and origins.
- Single-stranded conformation polymorphism (SSCP) of the intergenic spacer region (ISR).
- Amplified fragment length polymorphism (AFLP) fingerprinting.
- Multidimensional scaling (MDS) analysis to combine data.
Main Results:
- ISR-SSCP identified five distinct genotypes, with clear clustering of Kuwaiti and non-Kuwaiti isolates.
- AFLP provided higher resolution, distinguishing 13 genotypes, and revealed two profiles within Kuwaiti isolates.
- Combined analysis showed a strong correlation between geographical origin and S. agalactiae genotypes.
Conclusions:
- Both ISR-SSCP and AFLP effectively revealed genetic differences among fish-associated S. agalactiae.
- AFLP offers superior discriminatory power, while ISR-SSCP is a simpler, faster alternative.
- Genetic profiles are linked to the geographical source of S. agalactiae isolates from fish.
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