Comparison of culture-dependent and culture-independent molecular methods for characterization of vaginal microflora

Abstract

Purpose: To date, molecular methods that circumvent the limitations of traditional culture methods have not been used to describe the vaginal microflora in India. Here, we compared culture and culture-independent molecular methods in characterizing the vaginal microbiota in Indian women.

Methodology: Culture methods involved traditional cultivation on Rogosa and sheep blood agar, whereas culture-independent methods bypassed a culturing step by performing broadrange 16S rDNA PCR on DNA isolated directly from vaginal swabs.

Results: A total of 13 women were included in the study, of which five were characterized as healthy, two were bacterial vaginosis intermediate and six were bacterial vaginosis positive according to Nugent scoring. Lactobacillus jensenii was detected most frequently when using culture methods. On the other hand, Lactobacillus iners, which was not detected by culture methods, was the most common Lactobacillus sp. detected using cultivation-independent methods.

Conclusion: We found little overlap between the species found using cultivation-dependent and cultivation-independent methods. Rather, culture-dependent and culture-independent methods were found to be complementary in describing the vaginal microflora among South Indian women. Culture-independent methods were found to be superior in detecting clinically relevant vaginal flora.

Fig. 1.

Study flowchart showing the number of samples and species isolated using culture-dependent (CD) and culture-independent (CI) methods among women of reproductive age in Mysore, India.

Fig. 2.

Bar graph showing the percentage of Indian women harboring an individual Lactobacillus sp. when using culture-dependent (dark grey) and culture-independent (light grey) methods in Mysore, India.