A pregnant patient is screen for Group B Streptococcus (GBS)…
A pregnant patient is screen for Group B Streptococcus (GBS) at 36 weeks gestation. A vaginal swab is collected and cultured in Todd-Hewett broth with antibiotics. The broth is subcultured to a BAP after 24 hours of incubation. No GBS are seen on the subculture and the results are reported as negative. The patient later delivers an infant with early onset GBS disease. What is the most likely reason for the negative GBS culture?