Distinctive features of surface-anchored proteins of Streptococcus agalactiae strains from Zimbabwe revealed by PCR and dot blotting

Clin Vaccine Immunol. 2008 Sep;15(9):1420-4. doi: 10.1128/CVI.00112-08. Epub 2008 Jul 30.

Abstract

The distribution of capsular polysaccharide (CPS) types and subtypes (serovariants) among 121 group B streptococcus (GBS) strains from Zimbabwe was examined. PCR was used for the detection of both CPS types and the surface-anchored and strain-variable proteins Calpha, Cbeta, Alp1, Alp2, Alp3, R4/Rib, and Alp4. The R3 protein was detected by an antibody-based method using monoclonal anti-R3 antibody in dot blotting. The CPS types detected, Ia (15.7% of strains), Ib (11.6%), II (8.3%), III (38.8%), V (24.0%), and nontypeable (1.7%), were essentially as expected on the basis of data from Western countries. The type V strains showed distinctive features with respect to protein markers in that Alp3 was detected in only 6.9% of the isolates while R3 occurred in 75.9% and R4/Rib occurred in 37.9% of the isolates. R3 occurred nearly always in combination with one of the alpha-like (Alp) proteins, and it was the third most common of the proteins studied. These results show that type V GBS strains from Zimbabwe differed from type V strains from other geographical areas and also emphasize the importance of the R3 protein in GBS serotyping and its potential importance in the immunobiology of GBS, including a potential role in a future GBS vaccine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Carrier State / microbiology*
  • Female
  • Genotype
  • Humans
  • Infant, Newborn
  • Membrane Proteins / genetics*
  • Polymerase Chain Reaction / methods*
  • Polysaccharides, Bacterial / genetics
  • Pregnant Women
  • Serotyping
  • Streptococcus agalactiae / classification*
  • Streptococcus agalactiae / genetics*
  • Streptococcus agalactiae / isolation & purification
  • Zimbabwe

Substances

  • Bacterial Proteins
  • Membrane Proteins
  • Polysaccharides, Bacterial