Identifying probiotic characteristics of Lactobacillus crispatus isolated from the vagina

Lactobacilli prevent overproduction of pathogenic microorganisms and contribute protecting vaginal microbiota. Many probiotic microorganisms are categorized as Lactic Acid Bacteria. In this study, it was aimed identifying probiotic characteristics of Lactobacillus crispatus isolated from the vagina of a healthy woman. For this purpose, lactic acid, hydrogen peroxide and proteolytic activity quantities and auto-aggregation, co-aggregation and hydrophobicity abilities of Lactobacillus crispatus, which has been isolated and identified by 16s rRNA sequence analysis, were determined. Additionally, bile salt and acid resistance, along with antibiotic susceptibility of Lactobacillus crispatus were analyzed by the end of 3 hours. Lactic acid, hydrogen peroxide and proteolytic activity quantities of Lactobacillus crispatus were measured 2.275%, 0.334±0.075 µg/mL and 2.131±0,000 mg/mL respectively. The findings include existence of co-aggregation and auto-aggregation ability, but not hydrophobicity. By the end of 3 hours, the viability was preserved in 0.1% and 0.3% bile salt medium and, at pH 3. L. crispatus exhibited resistance to methicillin, metronidazole, oxacillin, and sulfamethoxazole + trimethoprim, but the bacteria exhibited susceptibility to tested the other antibiotics. This study will make an important contribution to the literature about probiotic characteristics of L. crispatus and our strain isolated from the vagina might be considered as a candidate probiotic.

乳杆菌属（Lactobacilli）可抑制病原微生物过度增殖，有助于维持阴道微生物群的稳态。许多益生菌微生物被归类为乳酸菌（Lactic Acid Bacteria）。本研究旨在鉴定从健康女性阴道分离的卷曲乳杆菌（Lactobacillus crispatus）的益生菌特性。为此，本研究通过16S rRNA序列分析分离并鉴定出该卷曲乳杆菌，随后对其乳酸、过氧化氢及蛋白水解活性水平，以及自身聚集、协同聚集和疏水性能进行了测定。此外，本研究于3小时终点时分析了该菌株的胆盐、酸耐受性以及抗生素敏感性。经检测，该卷曲乳杆菌的乳酸含量为2.275%，过氧化氢含量为0.334±0.075 μg/mL，蛋白水解活性水平为2.131±0.000 mg/mL。研究结果显示该菌株具备协同聚集与自身聚集能力，但不具备疏水性能。在3小时终点时，该菌株在0.1%和0.3%胆盐培养基以及pH为3的环境中仍保持存活。卷曲乳杆菌对甲氧西林、甲硝唑、苯唑西林以及磺胺甲恶唑+甲氧苄啶表现出耐药性，但对其余受试抗生素均表现出敏感性。本研究可为卷曲乳杆菌的益生菌特性相关研究文献提供重要参考，本研究从阴道分离得到的该菌株可作为候选益生菌加以考量。