Abstract
The genetic variability among Streptococcus agalactiae isolates recovered from fish was characterized using single‐stranded conformation polymorphism (SSCP) analysis of the intergenic spacer region (ISR), and amplified fragment length polymorphism (AFLP) fingerprinting. A total of 46 S. agalactiae cultures isolated from different fish species and geographic origins as well as related reference strains were included in the study. ISR‐SSCP divided the S. agalactiae isolates analysed into five distinct genotypes. Genotype 1 grouped all Kuwait isolates while genotype 4 clustered the majority of non‐Kuwait isolates (USA, Brazil and Honduras). AFLP analysis offered a higher resolution level by dividing the isolates into 13 different genotypes. Two different AFLP profiles were identified within the Kuwait isolates. When data from both ISR‐SSCP and AFLP were combined through a multidimensional analysis (MDS), a good correlation between geographical origin and genotypes was observed. Both AFLP and ISR‐SSCP revealed genetic differences between S. agalactiae isolates from fish. While AFLP offered a higher resolution, ISR‐SSCP also provided valid information being a simpler and faster method.