Development of Colony Multiplex PCR for Rapid Identification of Streptococcus suis serotype 2 and 1/2

Abstract

Streptococcus  suis  (S. suis) is an emerging zoonotic. This  bacterium causes many

pathological conditions such as, meningitis,  septicemia, endocarditis,  septic arthritis  and death.

To date, molecular  serotyping method has not distinguished  S.  suis   serotype 2 from serotype

1/2 because cps genes of these serotypes share highly similar  sequences. In this study, multiplex

PCR  assay was developed to distinguish  S.  suis   serotype 2 from 1/2. New set of primers were

designed for amplification of variable regions in nucleotide spacer between cpsS  gene and cpsT

gene combining  with  published primer  set. The  result  indicated that the colony  multiplex

PCR   assay is  able to differentiate these two serotypes in  reference strains. For  specificity

test, several  gram positive and negative bacteria were tested and amplicons  were detected only

when using universal primer set. The PCR  showed limit of detection for  S.  suis  at 100 CFU/

reaction. It  was concluded that this assay is  sensitive, specific,  simple and cost-effective.

However,  before this method could be performed for clinical  microbiology  laboratory or for

epidemiological studies the multiplex PCR  assay should be further evaluated with more S. suis

serotypes and related bacterial species.