Which of the following organisms would most likely be isolated from the vagina of a normal 5 year old girl?
**Core Concept**
The normal vaginal flora of prepubertal girls is predominantly composed of lactobacilli, which play a crucial role in maintaining vaginal pH and preventing infections. This is due to the presence of estrogen receptors in the vaginal epithelium, which are not yet active in prepubertal girls.
**Why the Correct Answer is Right**
Lactobacilli, specifically Lactobacillus jensenii and Lactobacillus crispatus, are the predominant organisms in the vaginal flora of prepubertal girls. They produce lactic acid as a byproduct of glucose metabolism, which maintains a low vaginal pH. This acidic environment inhibits the growth of pathogenic organisms, such as Gardnerella vaginalis and Bacteroides species.
**Why Each Wrong Option is Incorrect**
**Option A:** Gardnerella vaginalis is often associated with bacterial vaginosis in adult women, especially during the reproductive years. It is not typically found in prepubertal girls.
**Option B:** Bacteroides species are anaerobic bacteria commonly found in the gastrointestinal tract and are not typically isolated from the vagina of normal prepubertal girls.
**Option C:** Candida species can cause vulvovaginal candidiasis, but they are not the predominant organisms in the vaginal flora of prepubertal girls.
**Clinical Pearl / High-Yield Fact**
In prepubertal girls, the presence of lactobacilli in the vagina is a normal finding, whereas the presence of other organisms may indicate infection or abnormal vaginal flora.
**Correct Answer:** C. Lactobacillus species.