Detection of the C protein gene among group B streptococci using PCR.
OBJECTIVE
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.
Mawn
J A
JA
Department of Medical Microbiology, St Bartholomew's Hospital, West Smithfield, London.
Simpson
A J
AJ
Heard
S R
SR
D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D015139:Blotting, Southern; D005784:Gene Amplification; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013292:Streptococcus agalactiae / Q000235:genetics*
D001426:Bacterial Proteins; C039214:Ibc proteins, Streptococcus