Preliminary characterization of the normal microbiota of the human vulva using cultivation-independent methods

Abstract

The objective of this study was to perform a preliminary characterization of the microbial populations of the normal human vulva. Genomic DNA was isolated from samples of the labia majora and labia minora from four healthy women, and sequences of bacterial 16S rRNA genes in each were determined. The sequences were compared with those of known bacterial species to classify the numerically abundant populations in these communities. Even among this limited number of individuals, the microbiota of the human vulva was found to be quite diverse. Each woman had a distinctive microbiota and no single species was common to all women. The microbiota of the labia majora and labia minora differed, although both had appreciable numbers of lactobacilli and strict anaerobes. A greater diversity of populations inhabited the labia majora compared with the labia minora. The results indicated that the microbiota of the vulva includes populations known to be commensals of the microbiota of the skin, colon and vagina, and is much more complex than previously thought, suggesting that more extensive investigations are warranted. INTRODUCTIONThe human vulva consists of several distinct ecotopes that are defined by their physical and chemical characteristics. The physical characteristics include distinct histological architectures and anatomical proximity to the vagina, urethra, anus and Bartholin's gland, whilst the chemical factors include the composition and amount of vaginal secretions, as well as contamination by urine and faecal material. As a result, the microbiota of the human vulva is complex and unique (Elsner & Maibach, 1990). Cultivationdependent methods have been used previously to study the microbiology of the labia majora. The microbiota of the labia majora is characterized by micro-organisms that are either related to vaginal and urethral inhabitants (such as Lactobacillus spp.) or are common for intertriginous skin, including Gram-negative rods, non-pathogenic Neisseria, Gardnerella vaginalis and Staphylococcus aureus (Aly et al., 1979;Elsner & Maibach, 1990). Technical difficulties in the isolation of bacteria have confounded efforts to obtain a comprehensive understanding of the organisms present in various anatomical locations on the human body (Berg, 1999;Henderson et al., 1998; Hooper et al., 2001;Pace, 1997;Rappe & Giovannoni, 2003;Tlaskalová-Hogenová et al., 2004). This raises the possibility that organisms that normally reside in the human vulva were overlooked in previous studies that employed cultivation-dependent methods.Micro-organisms present on the vulva of healthy women may have clinical significance because their presence may affect the proliferation of non-indigenous populations (Atassi et al., 2006;Reid & Burton, 2002), including those that play a crucial role in triggering various common diseases such as vulvovaginitis (Wilson, 2005), urinary tract infection (Reid, 1999), bartholinitis (Nakatsu et al., 1998; Sing et al., 1998) and abscesses of Bartholin's gland (Tanaka et al., 2005). Vulvovaginitis ...

(GTG)5-PCR fingerprinting of lactobacilli isolated from cervix of healthy women

“…In contrast, L. acidophilus, which is generally considered the most common inhabitant of the female genital tract, was not isolated in the present study. Similar observations were published in several recent studies (e.g., Brown et al 2007;Dimitonova et al 2008;Kiss et al 2007) and show that L. acidophilus strains reported in some works may be representatives of other species from the L. acidophilus complex (such as, e.g., L. crispatus or L. gasseri). Altogether, 43 Lactobacillus strains were isolated from 31 persons.…”

Identification of novel mechanisms involved in generating localized vulvodynia pain

“…We found that vestibular fibroblasts from LPV cases are intrinsically sensitive to even very low infectious doses of C. albicans , cell numbers that fall within the range of what might be present in the normal microbiota of women 70-74 . Previous studies by our group and others, demonstrate that vestibular cells possess an “immunological memory,” where repeated infections with C. albicans predispose these cells to the production of elevated levels of pro-inflammatory mediators, even after the stimulus is removed 10, 11, 13 .…”

Promiscuity in mice is associated with increased vaginal bacterial diversity

“…and opportunistic pathogens (e.g., many Pseudomonas spp .) have been described in the lower reproductive tract of females of multiple species including humans (Kim et al 2009; Witkin et al 2007; Brown et al 2007), red-winged blackbirds (Hupton et al 2003), and the koala (Weigler et al 1988). Although explicit tests of the host fitness consequences of these infections are generally lacking, given that bacterial infections have been shown to be able to influence host phenotype (Brook 2005; Servin 2004), we might expect to see fitness effects associated with the bacterial colonization of reproductive structures.…”