The role of acidification in the inhibition of Neisseria gonorrhoeae by vaginal lactobacilli during anaerobic growth
The role of acidification in the inhibition of Neisseria gonorrhoeae by vaginal lactobacilli during anaerobic growth
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DOI：
10.1186/1476-0711-10-8
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发表时间：
2011-01-01
影响因子：
5.7
通讯作者：
Wade, Jeremy J.
中科院分区：
文献类型：
--
作者：
Graver, Michelle A.;Wade, Jeremy J.
背景：阴道乳杆菌通过产生乳酸、细菌素、过氧化氢或局部免疫反应来保护女性生殖道。在细菌性阴道病中，正常的乳酸菌被厌氧菌所取代，这可能会增加对淋球菌的易感性，淋球菌是一种兼性厌氧菌。在厌氧条件下，在液体培养条件下，还没有研究过阴道乳杆菌和淋球菌之间的细菌干扰。通过将淋球菌与乳杆菌共培养，我们试图确定酸化和过氧化氢的产生对淋球菌生长抑制的相对贡献。方法：在含有和不含有2-(N-吗啉)乙磺酸(MES)缓冲液的厌氧液体培养基中，培养在高浓度(10(7)-10(8)cfu/mL)的3株淋球菌上。用核梭杆菌作为厌氧菌的指示物。分别在15、20和25h进行细菌计数，并在25h测定pH值和过氧化氢浓度。结果：在25h时，核假单胞菌生长到10(8)cfu/m L时确认厌氧。所有细菌均在厌氧液体培养基中生长，添加MES缓冲液对生长影响不大。卷曲乳杆菌和加瑟氏乳杆菌对淋病奈瑟菌的生长有明显的酸化作用和相应的抑制作用。这种抑制作用可被MES的加入所消除。简氏乳杆菌产生的酸化较少，对淋病奈瑟菌没有抑制作用。结论：在厌氧生长过程中，所测试的阴道乳酸菌对淋球菌的抑制作用主要是由于酸化作用所致，而缓冲液的存在可使其抑制作用减弱。在这些条件下，除了产酸之外，没有证据表明抑制的具体机制，特别是没有产生过氧化氢。阴道乳杆菌在厌氧条件下的酸化潜力可能是它们最重要的特性，赋予它们对淋球菌感染的保护作用。
Background: Vaginal lactobacilli protect the female genital tract by producing lactic acid, bacteriocins, hydrogen peroxide or a local immune response. In bacterial vaginosis, normal lactobacilli are replaced by an anaerobic flora and this may increase susceptibility to Neisseria gonorrhoeae, a facultative anaerobe. Bacterial interference between vaginal lactobacilli and N. gonorrhoeae has not been studied in liquid medium under anaerobic conditions. By cocultivating N. gonorrhoeae in the presence of lactobacilli we sought to identify the relative contributions of acidification and hydrogen peroxide production to any growth inhibition of N. gonorrhoeae.Methods: Three strains of N. gonorrhoeae distinguishable by auxotyping were grown in the presence of high concentrations (10(7)-10(8) cfu/mL) of three vaginal lactobacilli (L. crispatus, L. gasseri and L. jensenii) in an anerobic liquid medium with and without 2-(N-morpholino)-ethanesulfonic (MES) buffer. Fusobacterium nucleatum was used as an indicator of anaerobiosis. Bacterial counts were performed at 15, 20 and 25 h; at 25 h pH and hydrogen peroxide concentrations were measured.Results: Growth of F. nucleatum to >10(8) cfu/mL at 25 h confirmed anaerobiosis. All bacteria grew in the anaerobic liquid medium and the addition of MES buffer had negligible effect on growth. L. crispatus and L. gasseri produced significant acidification and a corresponding reduction in growth of N. gonorrhoeae. This inhibition was abrogated by the addition of MES. L. jensenii produced less acidification and did not inhibit N. gonorrhoeae. Hydrogen peroxide was not detected in any experiment.Conclusions: During anaerobic growth, inhibition of N. gonorrhoeae by the vaginal lactobacilli tested was primarily due to acidification and abrogated by the presence of a buffer. There was no evidence of a specific mechanism of inhibition other than acid production under these conditions and, in particular, hydrogen peroxide was not produced. The acidification potential of vaginal lactobacilli under anaerobic conditions may be their most important characteristic conferring protection against N. gonorrhoeae infection.