Which organism is CAMP test positive and hippurate test positive, associated with meningitis and sepsis in newborns, and colonizes the vagina?

• A. Staphylococcus aureus
• B. Streptococcus viridans
• C. Streptococcus agalactiae
• D. Enterococcus faecalis

Answer: (C)

Understanding what the CAMP test and hippurate hydrolysis indicate helps identify group B Streptococcus, Streptococcus agalactiae. The CAMP test relies on a marker strain of Staphylococcus aureus; Streptococcus agalactiae produces a CAMP factor that enhances the beta-hemolysis of red blood cells, creating a characteristic arrowhead zone of hemolysis where the two organisms meet. Hippurate hydrolysis is positive for S. agalactiae, meaning it can break down hippurate, a trait that helps distinguish it from other beta-hemolytic streptococci. Clinically, this organism commonly colonizes the vagina and GI tract and is a major cause of meningitis and sepsis in newborns due to vertical transmission during delivery, which is why maternal screening and intrapartum antibiotics are used. The other organisms listed do not consistently show both CAMP positivity and hippurate hydrolysis, or do not fit the neonatal disease and colonization pattern described.