Vaginal lactobacillus flora of healthy Swedish women

Abstract

Species of the Lactobacillus acidophilus complex are generally considered to constitute most of the vaginal Lactobacillus flora, but the flora varies between studies. However, this may be due to difficulties in identifying the closely related species within the L. acidophilus complex by using traditional methods and to variations in the vaginal status of the participants. Two hundred two isolates from the vaginal fluids of 23 Swedish women without bacterial vaginosis, as defined by the criteria of Nugent et al. (R. P. Nugent, M. A. Krohn, and S. L. Hillier, J. Clin. Microbiol. 29:297-301, 1991), were typed by randomly amplified polymorphic DNA (RAPD) analysis and identified to the species level by temporal temperature gradient gel electrophoresis, multiplex PCR, and 16S ribosomal DNA sequencing. The vaginal flora of most participants was dominated by a single RAPD type, but five of them harbored two RAPD types representing two different species or strains. The most frequently occurring species were Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus iners, and Lactobacillus jensenii. L. iners has not previously been reported as one of the predominant Lactobacillus species in the vagina.

FIG. 1.

TTGE patterns of representative vaginal Lactobacillus strains. Lanes S, standard. Lanes 1 to 6, L. crispatus strains: 1, 1B7; 2, 8R5; 3, 8R4; 4, 16B2; 5, 18 M7; 6, 26R6. Lanes 7 to 11, L. gasseri strains: 7, 5B1; 8, 6 M8; 9, 15R5; 10, 16R6; 11, 20 M47. Lane 12, L. jensenii strain 2RB5, Lane 13, L. iners strain 25B31.