Longitudinal study of the biotypes of Gardnerella vaginalis

Abstract

Gardnerella vaginalis is the predominant vaginal microorganism in women with bacterial vaginosis. However, this organism is also frequently isolated from women without signs or symptoms of vaginitis. Earlier studies have not revealed whether certain biotypes of G. vaginalis are more often associated with bacterial vaginosis or are more common in women who acquire bacterial vaginosis. We used a typing scheme based on tests for P-galactosidase, hippurate hydrolysis, and lipase, using oleate as a substrate. Of 261 strains tested, the distribution of biotypes observed was as follows: 1, 13%; 2, 9%; 3, 5%; 4, 7%; 5, 41%; 6, 15%; and 8, 10%. Biotype 7 was not observed. The distributions of biotypes from women with and without bacterial vaginosis were found to be significantly different, with the lipase-positive biotypes (biotypes 1, 2, 3, and 4) being more predominant in women with vaginosis (41 versus 23%, P = 0.003). Of 40 women with normal vaginal flora at the index visit who remained normal at follow-up, 23 (57%) acquired a new biotype of G. vaginalis. By comparison, 90% of the 30 women who developed bacterial vaginosis acquired a new biotype of G. vaginalis (P = 0.003). Women with bacterial vaginosis at the index visit who were not treated were no more likely than normal women to have a shift in G. vaginalis biotype. However, 86% of the 30 women with bacterial vaginosis who were treated with an antibiotic at the index visit acquired a different biotype (P = 0.04 compared with the value for untreated women) regardless of treatment success. A trend toward the acquisition of a new biotype was observed among women who had contact with a new sexual partner (81 versus 65%, P = 0.15). These data demonstrate that the lipase-positive isolates of G. vaginalis are associated with bacterial vaginosis. Women who acquire bacterial vaginosis are more likely to have a shift in biotype than women who had normal fora at the follow-up, suggesting that the G. vaginalis isolates recovered from women who develop bacterial vaginosis represent newly acquired strains rather than overgrowth of previously colonizing biotypes.

Focusing the diversity of Gardnerella vaginalis through the lens of ecotypes

“…More recently, comparative genomics studies have revealed substantial differences in gene composition that surpass even some of the most diverse species known (Ahmed et al, 2012;Harwich et al, 2010;Yeoman et al, 2010). Some studies suggest particular biotypes or genotypes display a greater association with BV (Benito, Vazquez, Berron, Fenoll, & Saez-Neito, 1986;Numanović et al, 2008), but results are inconsistent (Aroutcheva et al, 2001;Piot et al, 1984) and may be confounded by erroneous biotype identification (Moncla & Pryke, 2009) or the presence of multiple types of G. vaginalis within a single individual (Balashov et al, 2014;Briselden & Hillier, 1990;Santiago et al, 2011). It is then important to understand the functional basis of diversification in G. vaginalis that could impact how lineages interact with the host and other microbes, and not just genetic differentiation resulting from natural demographic processes.…”

Bacterial vaginosis.

“…In another study in which a clinical diagnosis was made by Gram stain criteria, 24 asymptomatic women with BV were monitored for 4 months. Seventeen had persistent BV, and seven became healthy without treatment (22). Several other studies have shown that spontaneous remission of the signs of BV occurs in 25 to 43% of adults (76,120,152) and adolescents (24).…”

Biotipos y susceptibilidad antimicrobiana de Gardnerella vaginalis

“…No existe una asociación clara entre ciertos biotipos y VB, como tampoco hay un franco predominio de algunos serotipos en la microbiota vaginal comensal. Briselden y Hillier utilizando el mismo esquema que Piot encontraron una mayor frecuencia de los biotipos lipasa positiva (biotipos 1-4) en VB, mientras que Benito y cols observaron una mayor frecuencia de los biotipos 2, 4, 5 y 7 (11,12). Por su parte, Piot y cols no observaron diferencias en la distribución de biotipos en pacientes con flora normal y VB (10).…”

“…Ocasionalmente, G. vaginalis puede dar origen a infecciones extragenitales; bacteremias (4), meningitis (5), abscesos (6), infección urinaria 7, o a infecciones genitales no relacionadas con VB, como uretritis (8), patologías en las que podría ser útil contar con otros antimicrobianos alternativos (9). Existe escasa información de los biotipos más frecuentes de este microorganismo en pacientes con VB (10)(11)(12), desconociéndose si existe alguna relación entre ciertos biotipos y una mayor resistencia antimicrobiana.…”