Approximately what percentage of group B streptococci can grow in 6.5% salt broth?

Group B streptococci, particularly Streptococcus agalactiae, can tolerate and grow in high-salt environments, which is a characteristic that differentiates them from many other streptococcal species. In a 6.5% sodium chloride broth, approximately 80% of group B streptococci are capable of growth. This high tolerance to salt is an important aspect in laboratory diagnostics, as it helps in the identification and differentiation of group B streptococci from other streptococci, which may not grow as well, or at all, in such hypersaline conditions.

The ability to thrive in this environment suggests that group B streptococci have adapted mechanisms to cope with osmotic stress, which is significant given their clinical implications in neonatal infections and other conditions. This characteristic is a key point in microbiological identification processes.