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Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus
Published on: September 5, 2013
Detection of the C protein gene among group B streptococci using PCR
J A Mawn1, A J Simpson, S R Heard
1Department of Medical Microbiology, St Bartholomew's Hospital, West Smithfield, London.
Aim:
To develop a polymerase chain reaction (PCR) for the specific detection of the C protein gene in strains of group B Streptococcus.
Methods:
A single primer pair derived from the nucleotide sequence of the IgA binding beta antigen of the C protein complex permitted the specific amplification of a 592 base pair DNA fragment from the C protein gene. After 35 cycles of amplification this product could be detected by agarose gel electrophoresis. Southern blot hybridisation confirmed that this product was the C protein gene.
Results:
PCR detected the C protein gene in 75 (63%) of 119 strains of group B streptococci analysed. The product was not detected in other Gram positive organisms, showing that this PCR assay was highly specific. The sensitivity of the assay was satisfactory to a dilution of 1 in 10,000 of extracted DNA.
Conclusions:
The C protein of group B streptococci is associated with neonatal sepsis. The specific detection of the C protein gene by PCR may help identify which strains are likely to be associated with infection by the organism.

