| Summary: | <p>Abstract</p> <p>Background</p> <p>The pathogenesis of bacterial vaginosis remains largely elusive, although some microorganisms, including <it>Gardnerella vaginalis</it>, are suspected of playing a role in the etiology of this disorder. Recently culture-independent analysis of microbial ecosystems has proven its efficacy in characterizing the diversity of bacterial populations. Here, we report on the results obtained by combining culture and PCR-based methods to characterize the normal and disturbed vaginal microflora.</p> <p>Results</p> <p>A total of 150 vaginal swab samples from healthy women (115 pregnant and 35 non-pregnant) were categorized on the basis of Gram stain of direct smear as grade I (n = 112), grade II (n = 26), grade III (n = 9) or grade IV (n = 3). The composition of the vaginal microbial community of eight of these vaginal swabs (three grade I, two grade II and three grade III), all from non-pregnant women, were studied by culture and by cloning of the 16S rRNA genes obtained after direct amplification. Forty-six cultured isolates were identified by tDNA-PCR, 854 cloned 16S rRNA gene fragments were analysed of which 156 by sequencing, yielding a total of 38 species, including 9 presumptively novel species with at least five species that have not been isolated previously from vaginal samples. Interestingly, cloning revealed that <it>Atopobium vaginae </it>was abundant in four out of the five non-grade I specimens. Finally, species specific PCR for <it>A. vaginae </it>and <it>Gardnerella vaginalis </it>pointed to a statistically significant co-occurrence of both species in the bacterial vaginosis samples.</p> <p>Conclusions</p> <p>Although historically the literature regarding bacterial vaginosis has largely focused on <it>G. vaginalis </it>in particular, several findings of this study – like the abundance of <it>A. vaginae </it>in disturbed vaginal microflora and the presence of several novel species – indicate that much is to be learned about the composition of the vaginal microflora and its relation to the etiology of BV.</p>
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