微生态制剂乳酸菌对阴道病原菌的抑制及益生特性评估

Probiotic properties and antagonistic activities of lactic acid bacteria from commercial probiotic products against vaginal pathogens

摘要:

微生态制剂因其调节菌群的潜力而受到广泛关注，但目前产品多以口服途径为主，针对生殖道外用途径的益生特性尚缺乏系统评价。目的 评估微生态制剂来源的乳酸菌(lactic acid bacteria, LAB)的外用益生特性，揭示菌株局部给药的潜力，为其在阴道健康领域的应用提供科学依据。方法 在主流电商平台通过关键词筛选出至少包含2种不同LAB菌种的常见口服微生态制剂7种(P1-P7)，另纳入1种临床微生态制剂(P8)，分离并鉴定制剂中的LAB菌株；通过在不同pH环境下培养，评估菌株的耐酸能力及在不同pH环境下的生长特性；通过病原菌共培养实验分析菌株的抑菌活性；利用溶血实验和基因组比对评价菌株的安全性。结果 各微生态制剂分离出的LAB菌种比例为：P1 50.0% (2/4)，P2 0 (0/4)，P3 66.7% (2/3)，P4 12.5% (1/8)，P5 33.3% (2/6)，P6 40.0% (2/5)，P7 0 (0/7)，P8 100.0% (1/1)；多数菌株在pH 6.0-7.0环境下生长良好，部分菌株在pH 4.0仍可维持生长；P4、P8菌株的耐低酸性能优于其他菌株；不同菌株对阴道常见病原细菌的抑制效果差异显著，P1-2、P5-1、P6-1及P6-2均表现出中高度广谱抑菌活性；除P8外的分离菌株均对阴道加德纳菌具有抑菌活性，P8对测试病原菌的抑菌活性较弱；P4、P5-2、P6-1和P6-2在3个不同初始浓度下对白色念珠菌的抑制率均达到99.73%以上，P5-1可达到94.64%以上；所有菌株均未表现出β溶血，且无耐药基因和毒力基因。结论 多种市售微生态制剂分离出的菌株展现了较好的病原菌抑制能力与良好的安全性，局部给药途径可能使菌株在女性生殖道健康领域更具实际应用价值。

Abstract:

Probiotic products have attracted increasing attention for their potential to modulate the microbiota. However, most commercial products are designed for oral administration, and their probiotic properties relevant to topical use in the reproductive tract remain insufficiently evaluated.Objective To assess the probiotic properties of lactic acid bacteria (LAB) derived from probiotic products, with a particular focus on their potential for topical application, thus providing scientific evidence for their use in vaginal health.Methods Seven common oral probiotic products (P1-P7) containing at least two different LAB species were selected from major e-commerce platforms via keyword screening, along with one clinical probiotic product (P8). LAB strains were isolated and identified from these products. We evaluated the acid tolerance, as well as the growth characteristics under different pH conditions, of the isolates by culturing them in the media of varying pH values. The antimicrobial activities of the isolates were determined via co-culture assays with pathogenic microorganisms, while hemolysis assays and genomic comparison were conducted to assess safety.Results The isolation rates of LAB strains from P1 to P8 were 50.0% (2/4), 0 (0/4), 66.7% (2/3), 12.5% (1/8), 33.3% (2/6), 40.0% (2/5), 0 (0/7), and 100.0% (1/1), respectively. Most strains grew well at pH 6.0-7.0, and some maintained growth at pH 4.0. Strains P4 and P8 exhibited superior acid tolerance to the others. The inhibitory effects of different strains against common vaginal pathogens varied significantly. Strains P1-2, P5-1, P6-1 and P6-2 demonstrated moderate to strong broad-spectrum inhibitory activity against all tested pathogens. Other isolated strains except P8 exhibited inhibitory activity against Gardnerella vaginalis, while strain P8 showed weak inhibitory activities against the tested pathogens. Strains P4, P5-2, P6-1, and P6-2 achieved inhibition rates exceeding 99.73% against Candida albicans across all three tested inoculum concentrations, and strain P5-1 reached an inhibition rate of over 94.64%. None of the strains exhibited β-hemolytic activity, and no antibiotic resistance or virulence genes were detected.Conclusion Several LAB isolates from commercial probiotic products exhibited notable inhibitory activities against pathogenic microorganisms and demonstrated good safety profiles. Topical administration may therefore offer greater practical value in promoting female reproductive tract health.