Molecular characterization of the bacterial flora of the murine female genital tract

Abstract

The female genital tract may harbor a potentially diverse microbial community that has not been thoroughly characterized, particularly in the murine system. A more complete knowledge of resident flora may enhance understanding of disease susceptibility and the persistence of infection which, in turn, may better guide research toward more efficacious treatments and protective measures. Organisms known to exist in this environment have largely been identified through cultivation. However, because the nutritional and environmental needs of previously uncultivated organisms cannot be anticipated, there are limitations to the use of this technique when attempting to characterize a community. Molecular techniques that take advantage of the conservation of ribosomal RNA have proven to be very useful for such efforts. The use of PCR in tandem with denaturing gradient gel electrophoresis (DGGE) allows for the characterization and comparison of microbial populations with relative ease and rapidity. This study applies these molecular techniques to the investigation of the microbial flora of the murine female genital tract. In addition, a comparison was made between cultivation and two different molecular techniques, DGGE and cloning. We found some overlap in the detection of organisms identified by the various methods, but some microbes were only detected by particular techniques. We further used DGGE to identify bacterial populations of this environment during the course of the natural estrous cycle, under the influence of exogenous hormones, following antibiotic therapy and in a Chlamydia trachomatis infection model. Our findings indicate that there is no change in the species present over the course of the estrous cycle or under the influence of administered hormones. However, because DGGE is not quantitative we were unable to determine if quantitative changes in the populations occurred. Our findings with the antibiotic treatment and Chlamydia infection model, though interesting, were not conclusive and require further investigation.