Vaginal pH and microbicidal lactic acid when lactobacilli dominate the microbiota.
Vaginal pH and microbicidal lactic acid when lactobacilli dominate the microbiota.
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DOI：
10.1371/journal.pone.0080074
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Cone RA
中科院分区：
文献类型：
--
作者：
O'Hanlon DE;Moench TR;Cone RA
在足够酸性的pH条件下，乳酸是一种有效的杀微生物剂，而阴道乳杆菌产生的乳酸可能有助于预防生殖道感染。然而，之前的观察可能低估了健康的阴道酸度和总乳酸浓度，因为它们未能排除没有乳酸菌主导的阴道微生物群的女性，也没有考虑到阴道的高二氧化碳、低氧气环境。56名Nugent评分低(0-3分)(表明阴道微生物群以乳酸菌为主)且没有生殖道疾病或感染症状的女性，使用一种避免了样本稀释和严格减少需氧暴露的收集方法，总共提供了宫颈阴道液样本。采集后立即用微电极测量阴道内生理浓度下的pH值。商业酶法测定总乳酸盐和总醋酸盐浓度已被证实可用于CVF，并与更常见的高效液相色谱法进行了比较。CVF样品的平均pH值为3.5±0.3(平均值±SD)，范围为2.8-4.2，平均总乳酸为1.0%±0.2wv；这是先前文献中平均氢离子浓度(低pH)的五倍和总乳酸浓度的五倍。因此，乳酸的杀微生物剂形式(质子化乳酸)的浓度是先前研究的11倍，也是一种明显更有效的杀微生物剂。这表明，当乳酸杆菌主导阴道微生物区系时，女性对乳酸介导的感染保护作用比目前认为的要明显更多。我们的结果要求进一步评估阴道乳酸的预防和治疗作用，无论是由内源性乳杆菌、益生菌或增强阴道乳酸的产品提供的原位提供的。
Lactic acid at sufficiently acidic pH is a potent microbicide, and lactic acid produced by vaginal lactobacilli may help protect against reproductive tract infections. However, previous observations likely underestimated healthy vaginal acidity and total lactate concentration since they failed to exclude women without a lactobacillus-dominated vaginal microbiota, and also did not account for the high carbon dioxide, low oxygen environment of the vagina. Fifty-six women with low (0-3) Nugent scores (indicating a lactobacillus-dominated vaginal microbiota) and no symptoms of reproductive tract disease or infection, provided a total of 64 cervicovaginal fluid samples using a collection method that avoided the need for sample dilution and rigorously minimized aerobic exposure. The pH of samples was measured by microelectrode immediately after collection and under a physiological vaginal concentration of CO2. Commercial enzymatic assays of total lactate and total acetate concentrations were validated for use in CVF, and compared to the more usual HPLC method. The average pH of the CVF samples was 3.5 ± 0.3 (mean ± SD), range 2.8-4.2, and the average total lactate was 1.0% ± 0.2% w/v; this is a five-fold higher average hydrogen ion concentration (lower pH) and a fivefold higher total lactate concentration than in the prior literature. The microbicidal form of lactic acid (protonated lactic acid) was therefore eleven-fold more concentrated, and a markedly more potent microbicide, than indicated by prior research. This suggests that when lactobacilli dominate the vaginal microbiota, women have significantly more lactic acid-mediated protection against infections than currently believed. Our results invite further evaluations of the prophylactic and therapeutic actions of vaginal lactic acid, whether provided in situ by endogenous lactobacilli, by probiotic lactobacilli, or by products that reinforce vaginal lactic acid.
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影响因子：
3.7
作者：
O'Hanlon DE;Lanier BR;Moench TR;Cone RA
通讯作者：
Cone RA
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发表时间：
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影响因子：
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