EVOLUTION OVER TIME – LOW RISK GROUP -The presence or absence of a particular Lactobacillus species appeared to remain constant throughout the study (Figure 2). No predictors (partner preference, being sexually active, PSA presence, time of cycle) of being "Lactobacillus consistently present (meaning at most one visit absent)" for any of the studied Lactobacillae were identified. Longitudinal analysis of women in this group, showed that L. crispatus counts were 0.22 log higher (p<0.001) and L. iners counts were 0.83 log lower (p<0.001) at the end of the menstrual cycle. L. crispatus counts were decreased by 0.42 log after intercourse (PSA present) (p=0.002), while those of L. iners (+0.73 log, p=0.033) and of L. gasseri (+0.59 log, p= 0.058) were increased. With latent class analysis (LCA) we identified two subsets of women based on the consistent presence of the Lactobacillus species (table 3). In the first subset of women, comprising 81% of the studied low risk population, L. crispatus, L. iners, L. jensenii, and L. gasseri are consistently present in, 66%, 82%, 70%, and 67% of women, respectively. The second subset comprising 19% of the low risk population is characterized by a prevalence of G. vaginalis and A. vaginae of 100% and 88%, respectively. A combination of a quick microscopic evaluation with Nugent score together with real time PCR defining exact presence and counts up to the species level will fine-tune the safety evaluation of vaginally applied products and this strategy should therefore be considered in future vaginal product development. Institute of Tropical Medicine, Antwerp Nationalestraat 155, B-2000 Antwerp, Belgium Tel Fax Quantifying Vaginal Flora Species with Real Time PCR for HIV prevention trials Introduction & Methods INTRODUCTION -A healthy vaginal environment is protective against STIs -Vaginal prevention products should not disturb this balance OBJECTIVES -To design reliable PCRs for quantification of specific vaginal flora species -To define baseline ranges in a healthy phase I population and compare with a high risk population METHODS: CLINICAL SET UP -LOW RISK population: healthy European phase I women, year, no hormones, N=30, 5 visits Results BASELINE CLINICAL CHARACTERISTICS -Presented in table 1. Twenty-one women were sexually active of whom 4 had a sexual preference for the same gender. Of the remaining 9 women, one had a sexual preference for the same gender. Prostate specific antigen (PSA) tested positive on 12 occasions over 7 women. Conclusions METHODS: LABORATORY SET UP -Extraction: Low risk - easyMag, BioMérieux. High risk – miniMag, BioMérieux. -Real time PCR: L. crispatus, L. iners, L. jensenii, L. gasseri, Lactobacillus sp., G. vaginalis, A. vaginae -2 swabs pooled in PBS -HIGH RISK population: STI clinic attenders, year, N=41, 2 visits -2 high vaginal flocked swabs (COPAN innovation, Italy) BASELINE VAGINAL FLORA – LOW AND HIGH RISK GROUP -Data are presented in table 2 and figure 1. -Extraction step (extra lysing step of the Easymag) resulted in a higher yield of DNA of 1 log difference in low risk women. PCR for human ERV was in agreement (results not shown). As a result we omitted the statistical comparison of the counts between the low and high risk women and we only present the comparison of counts within the high risk group. † Wilcoxon rank-sum test 1 Fisher exact test 2 counts in bacterial cells per ml PresenceCounts 2 Species Present n/N (%) Vs Low risk (p-value 1) Vs High Risk No BV (p-value 1 ) Geometric Mean Count (when present) Log 10 Geometric mean (when present) Vs High Risk No BV (p-value†) Lactobacillus total Low Risk30/30 (100) x ,97 High Risk:BV = 029/29 (100) x ,99-- BV = 112/12 (100) x ,041<0.001 L. crispatus Low Risk23/30 (77) x ,78 High Risk: BV = 023/29 (79) x ,59-- BV = 15/12 (42) x ,23<0.001 L. iners Low Risk20/30 (67) x ,74 High Risk: BV = 025/29 (86) x ,34-- BV = 110/12 (83) x , L. jensenii Low Risk17/30 (57)-- 40 x ,60 High Risk: BV = 015/29 (52) x ,74-- BV = 13/12 (25) x , L. gasseri Low Risk19/30 (63) x ,99 High Risk: BV = 07/29 (24) x ,75-- BV = 11/12 (8) (Single obs: 19 x 10 6 )7, G. vaginalis Low Risk10/30 (33) x ,11 High Risk: BV = 020/29 (69) x ,79-- BV = 112/12 (100)< x ,62<0.001 A. vaginae Low Risk4/30 (13) x ,93 High Risk: BV = 08/29 (28) x ,08-- BV = 111/12 (92)< x ,11<0.001 Table 2: Presence and counts of vaginal flora species for a low risk and high risk population in Antwerp, Belgium Low risk (N=30) High risk (N=41) ¹ Age (years)Mean (range)27 (19-38)27 (15-47) ² Race N (%)African/Caribbean0 (0)13 (34) Caucasian28 (93)11 (29) Hispanic0 (0)6 (16) Asian0 (0)5 (13) Mediterranean2 (7)3 (8) ³ Contraception N (%)None12 (40)18 (46) Combined pill0 (0)9 (23) Intrauterine device1 (3)8 (21) Implant0 (0)2 (5) Condoms17 (57)2 (5) Bacterial vaginosis 0 (0%)12 (29%) ¹ 5 missing values ² 4 missing values ³ 2 missing values Table 1:Baseline Clinical Characteristics Present at least at one visit Consistently present ‡ N=30 LCA 1 Subgroup1 81% Subgroup2 19% Lactobacillus sp.30 (100%) 100% L. crispatus28 (90%)18 (60%)66%36% L. iners23 (77%)20 (67%)82%0% L. jensenii22 (73%)19 (63%)70%18% L. gasseri21 (70%)20 (67%)67%47% G. vaginalis14 (47%)7 (23%)34%100% A. vaginae6 (20%)2 (7%)4%88% Table 3: Evolution of species presence and species counts over time – Low risk population ‡ At most 1 visit absent 1 With latent class analysis (LCA) we identified two subsets of women based on the consistent presence of the Lactobacillus species. Figure 1: Presence at baseline of species in counts/ml Figure 2: Log counts of bacterial cells per ml by day in the menstrual cycle. Wilcoxon-rank-sum-test-result: NS:p≤0.100,+:p<0.100,*:p<0.050,**:p<0.010,***:p< Vicky Jespers 1, Joris Menten 1, Rita Verhelst *, Hilde Smet 1, Sabrina Poradosú 1, Anne Buvé 1,Liselotte Hardy 1, Tania Crucitti 1 1 Institute of Tropical Medicine and * University of Ghent