Clinical Significance of a Single Positive Blood Culture for Group B Streptococcus

Understanding Blood Culture Results for Group B Streptococcus

According to the CDC guidelines, a recognized pathogen, such as Group B Streptococcus, cultured from one or more blood cultures meets the criteria for a true infection when not related to infection at another site, and Group B Streptococcus is considered a recognized pathogen, not a common skin contaminant, making even a single positive culture potentially significant 1
Unlike coagulase-negative staphylococci and other common contaminants that require two positive cultures from separate occasions, pathogens like Group B Streptococcus require only one positive culture to be considered significant 1
The presence of fever, chills, or hypotension in a patient with a single positive blood culture for GBS strongly suggests true bacteremia rather than contamination, according to the CDC guidelines 1

For penicillin-allergic patients, clindamycin is recommended as an alternative therapy for GBS infections, although increasing resistance has been observed 2