Identification and H ₂ O ₂ Production of Vaginal Lactobacilli from Pregnant Women at High Risk of Preterm Birth and Relation with Outcome

Abstract

Lactobacilli, principally the strains that are hydrogen peroxide (H 2 O 2 ) producing, may have a protective effect against vaginal colonization by pathogenic species such as those that cause bacterial vaginosis. Previous reports have also suggested that H 2 O 2 -producing lactobacilli in the vagina may protect pregnant women against ascending infection of the chorioamniotic membranes and uterine cavity. We report the identification and H 2 O 2 production of lactobacilli isolated from vaginal swabs collected at 20 weeks' gestation from a population of pregnant women at high risk of preterm birth. We also report the correlation between identification and H 2 O 2 production in relation to the outcomes of chorioamnionitis and preterm birth. Lactobacilli were identified by partial 16S rRNA gene sequencing. H 2 O 2 production by isolates was determined by a semiquantitative method. The most commonly isolated species were L. crispatus, L. gasseri, L. vaginalis and L. jensenii. Amounts of H 2 O 2 produced by lactobacilli varied widely. The presence of lactobacilli producing high levels of H 2 O 2 in the vagina of this population of pregnant women was associated with a reduced risk of bacterial vaginosis at 20 weeks' gestation and subsequent chorioamnionitis. L. jensenii and L. vaginalis produced the highest levels of H 2 O 2 . We postulate that H 2 O 2 -producing lactobacilli are able to reduce the incidence of ascending infections of the uterus and the subsequent production of proinflammatory molecules which are important in the pathogenesis of chorioamnionitis and preterm birth.The adult human vagina is a complex ecosystem containing an abundance of microorganisms. In women of childbearing age this system is dominated by Lactobacillus spp., a genus of gram-positive, nonmotile rod-like bacteria, a defining characteristic of which is the ability to grow in acid media and tolerate acid conditions (pH Ͻ 4.5); lactobacilli also ferment carbohydrates to produce lactic acid. In bacterial vaginosis (BV) the balance of flora is changed with reduced numbers of lactobacilli and an increase in numbers of other facultative and anaerobic species such as anaerobic cocci Prevotella spp., Gardnerella vaginalis, and Mobiluncus spp. BV is associated with a number of poor health outcomes, including preterm birth (31). Lactobacilli, principally the strains that are H 2 O 2 producing, may have a protective effect against vaginal colonization by pathogenic species such as those that cause BV (16) and possibly human immunodeficiency virus and gonorrhoea (26). Previous reports have also suggested that H 2 O 2 -producing lactobacilli in the vagina may protect pregnant women against ascending infection of the chorioamniotic membranes and uterine cavity (12, 18). There have been few studies in which lactobacilli have been identified to species level and in which H 2 O 2 production in pregnant women has been determined. We report the identification and H 2 O 2 production of lactobacilli isolated from vaginal swabs collected at 20 weeks' gestatio...

Comparison of Lactobacillus crispatus isolates from Lactobacillus-dominated vaginal microbiomes with isolates from microbiomes containing bacterial vaginosis-associated bacteria

“…In fact, even H 2 O 2 -non-producing strains of L. crispatus appear to play a protective role (Verstraelen et al, 2009). Recent studies suggest that lactic acid is the main defence mechanism against BV-associated bacteria and that H 2 O 2 levels are insignificant in the vaginal environment (Kaewsrichan et al, 2006;O'Hanlon et al, 2013;Wilks et al, 2004). In another recent study, the ratios of D-and L-lactic acid (isomers of lactic acid) varied in women with different vaginal communities, suggesting that different lactic acidproducing bacteria produce the two isomers in different ratios (Witkin et al, 2013).…”

“…There are at least five Lactobacillus species that can colonize the vagina: Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus jensenii, Lactobacillus vaginalis and Lactobacillus iners (Antonio et al, 1999;Fettweis et al, 2014;Madhivanan et al, 2015;Wilks et al, 2004). Bacterial vaginosis (BV) is a common clinical condition characterized by a dramatic increase in both bacterial species diversity and overall bacterial burden.…”

Effect of iron on the probiotic properties of the vaginal isolate Lactobacillus jensenii CECT 4306

“…Since the first microbiological study of the human vagina, lactobacilli have been considered the dominant members of the microbiota of this organ (Doderlein, 1982), a finding that has been further confirmed by several recent metagenomic studies (Biagi et al, 2009;Fettweis et al, 2012;Martín et al, 2014;Pavlova et al, 2002;Song et al, 1999;Verhelst et al, 2004;Vitali et al, 2007;Wilks et al, 2004;Zhou et al, 2004). In total, around 20 different species of lactobacilli have been consistently isolated from the vagina, although only one or two species predominate at a time in a given individual.…”

“…In total, around 20 different species of lactobacilli have been consistently isolated from the vagina, although only one or two species predominate at a time in a given individual. Dominant strains vary as a function of race and lifestyle, but strains of Lactobacillus crispatus, Lactobacillus iners, Lactobacillus jensenii and Lactobacillus gasseri are the most frequent (Biagi et al, 2009;Pavlova et al, 2002;Song et al, 1999;Verhelst et al, 2004;Vitali et al, 2007;Wilks et al, 2004;Zhou et al, 2004).…”

Current views on vaginal microbiota and its impact on pregnancy outcomes

“…Установлено, что наличие лактобацилл, продуцирующих высокий уровень перекиси водорода, ассоциировано с низкой частотой БВ, преждевременных родов и послеродовых инфек ционных осложнений [10,11]. Изучение генотипических и биохимических свойств ваги-нальных лактобацилл показало, что L. crispatus, L. jensenii и L. vaginalis представляют собой наиболее часто встречающиеся виды перекиси продуцирующих лактобацилл [12].…”