Streptococcus agalactiae (also known as group B streptococcus [GBS]) is associated with various diseases such as neonatal disease, sepsis, arthritis, pneumonia, meningitis, skin and soft tissue infections.
Host colonization and virulence are mainly studied using microscopy and fluorescent biomarkers. Strategies for labelling GBS with fluorescent biomarkers have so far been limited to antibody-based immunostaining methods and nonspecific protein/DNA stains.
Green fluorescent protein (GFP) expression is a common labeling method for bacteria, enabling their identification in complex samples or monitoring of their subcellular locations in eukaryotic host cells. We have recently reported1 stable expression of a green fluorescent protein mutant (GFPmut3) with enhanced fluorescence intensity in GBS. Validation and stability of GFPmut3 expression in GBS cultures was measured by the CLARIOstar multi-mode plate reader and its fluorescence intensity, fluorescence polarization and absorbance measurement capabilities.