vaginae and G. vaginalis specific primers obtained for 50 neovaginal samples.     Gardnerella vaginalis     + – Total Atopobium vaginae + 12 17 29   – 3 18 21   Total 15 35 50 The samples that were PCR positive for G. vaginalis were selected for amplification with bacterial vaginosis associated

bacteria (BVAB) primers. All 15 specimens were PCR negative for BVAB1 and BVAB3 and only one specimen, positive for both A. vaginae and G. vaginalis, was PCR positive for BVAB2. Remarkably, 41 of 50 neovaginal specimens showed an amplicon after amplification with M. curtisii primers (Table 3). Of these, 36 (88%) could be confirmed using Mobiluncus genus specific primers. Table 3 Detection of Mobiluncus curtisii in 30 neovaginal samples: comparison between Gram stain, culture and species specific primers.   C+P+ C+P- C-P+ C-P- Total G+ 6 FDA-approved Drug Library manufacturer 0 6 1 13 G- 4 0 10 find more 3 17 G+/-: Presence or absence of Mobiluncus cell types on Gram stain. C+/-: Presence of absence of M. curtisii after anaerobic incubation on Columbia-based blood agar. P+/-: Presence or absence of an amplicon after amplification with M. curtisii specific primers. After amplification of the neovaginal DNA extracts with primers that target the ITS2-region

of the rRNA cistron of Fungi and size determination of the amplified ITS2 by means of capillary electrophoresis, 6 specimens revealed an amplicon. Three specimens could not be sequenced and the remaining three sequences were identified as molds (resp. Davidiella tassiana, Lycoperdon perlatum and Phaeosphaeria sp.). The PCR assay for Chlamydia on urine was negative for all participants. Discussion The pH of the neovagina of the transsexual women in our study was consistently elevated (mean 5.8; range 5.0–7.0) as compared to that of the biological vagina. This is not unexpected as the acidic pH (3.8–4.5) of the vagina results primarily

from lactic acid production by the resident lactobacilli [9, 10] and is Interleukin-2 receptor further enhanced through acidification by an active proton pump action of the vaginal epithelium – a mechanism upregulated by oestrogen [11]. In our patient series however, lactobacilli were consistently lacking, with only one transsexual woman with a penile skin-lined neovagina displaying some lactobacilli. As expected, and although these women show serum oestradiol levels comparable to those in substituted postmenopausal women, the environment of this penile skin-lined neovagina, does not support the growth of lactobacilli. This might be due to the absence of glycogen rich epithelial cells and to the absence of lactobacillus epithelial binding sites that are upregulated by oestrogen in the normal vaginal mucosa. Our study indicates that the microflora of the neovagina is characterized by bacterial species from the skin and the intestinal microflora, somewhat similar to what is observed with premenarchal girls, who also lack a Lactobacillus dominated microflora, eliciting colonisation resistance.