Question 176

Question:

A 1-day-old newborn is evaluated for possible sepsis. Blood cultures grow gram-positive cocci in pairs and chains that agglutinate with group B antiserum. The most likely epidemiologic risk factor for this infection involves bacterial colonization of which of the following?

Correct Answer: A.  Mother’s vagina

The description of the bacteria is significant because it identifies the organism as group B streptococcus. Group B strep is a very common cause of newborn meningitis and sepsis, and it is most often found colonizing the mother’s vagina (option A).
The newborn’s GI tract (B) is not completely sterile, but group B strep is not part of the flora.
Colonization of the newborn’s nasopharynx (C) is incorrect because the infection is not transmitted by the respiratory route, nor is it transplacental infection (D) (For transplacental think TORCH), nor would it colonize the umbilical cord remnant (E) (an infection here would most likely be from an anaerobic bacteria).