APPLICATION OF MULTIPLEX-PCR TO DETERMINE SEROTYPE AND VIRULENCE GENES OF Streptococcus agalactiae CAUSING DISEASE IN NILE TILAPIA

Abstract

Because of its superiority, multiplex-PCR is frequently used in molecular characterization to identify several target genes in the same reaction, conserving time, chemicals, effort, and achieving high efficiency. In this study, we used multiplex-PCR to detect the serotype and virulence genes of S. agalactiae that cause disease in Nile tilapia. The My Taq^TM HS Mix 2 kit was utilized to optimize the multiplex-PCR reaction, which used 2-step thermal cycling. S. agalactiae that causes disease in Nile tilapia in Vietnam has serotypes Ia and III, which comprise 11-13 virulence genes from three main virulence groups (adhesion, invasion, and immune evasion). It proves that all of the strains are virulent. This result will be used to determine the virulence of S. agalactiae in order to develop molecular markers (microsatellites and SNPs) for selective breeding of disease-resistant Nile tilapia in Vietnam.