乳杆菌活菌胶囊在配合治疗产后滴虫性阴道炎中的价值

目的探讨应用乳杆菌活菌胶囊在配合治疗产后滴虫性阴道炎中的作用。方法将90例患滴虫性阴道炎的产后妇女随机分为2组,研究组应用甲硝唑400 mg,每日2次,连服7 d,同时每日晚塞1粒乳杆菌活菌胶囊入阴道,连用10 d;对照组应用甲硝唑400 mg,每日2次,连服7 d。2组患者14 d后复查并检查白带常规,对其临床治愈率、白带清洁度、pH进行比较。30 d后随访检查滴虫性阴道炎复发情况。结果用药后研究组治愈率高于对照组,2组差异有统计学意义(P<0.05);研究组、对照组pH均有降低,但研究组pH低于对照组,2组差异有统计学意义(P<0.05);用药后研究组阴道清洁度I、II度比率高于对照组,研究组复发率低于对照组,差异均有统计学意义(P<0.05)。结论产妇应用乳杆菌活菌胶囊配合治疗滴虫性阴道炎可提高治愈率,改善阴道微环境并降低复发率。     

乳酸杆菌发酵滤液中核酸抗肿瘤效应及对荷瘤鼠免疫功能的影响

目的探讨乳酸杆菌DM9811培养基滤液中核酸在体外对肿瘤细胞生长及对荷瘤鼠免疫功能的影响。方法抽提乳酸杆菌DM9811对数生长期培养基滤液中核酸,进行琼脂糖电泳分析;MTT法体外观察其对于结肠癌HT-29细胞系生长的影响;动物实验观察不同组别小鼠生存期、瘤重体重比、NK细胞活性、T细胞亚群指标。结果乳酸杆菌DM9811滤液中核酸组分为RNA;在细胞浓度为1×106时,每孔加入RNA 100μg能够明显抑制结肠癌HT-29细胞系的生长;预防组荷瘤鼠除CD8＋T细胞比例之外各项指标与阴性对照组相比差异都有统计学意义（P〈0.05）,其中NK细胞杀伤活性（58.97±3.62）、CD4＋T细胞比例（27.77±5.40）和生存期（15.1±4.48）均高于阴性对照组（43.87±3.92）、（19.68±3.00）、（10.2±3.08）,瘤重体重比（0.029±0.017）低于阴性对照组（0.066±0.024）;治疗组生存期（11.8±3.12）与阴性对照组（10.2±3.08）相比差异有统计学意义（P〈0.05）,治疗组生存期长于阴性对照组。结论乳酸杆菌DM9811培养基滤液中存在核酸组分,为100200 bp的RNA片段。100μg/mL乳酸杆菌DM9811培养基滤液中RNA组分对结肠癌HT-29细胞系生长有明显抑制作用。RNA组分可以上调荷瘤鼠的细胞免疫水平,延长荷瘤鼠的生存期。     

乳杆菌对数生长期培养基滤液核酸组分分析

目的通过对乳杆菌对数生长期培养基滤液中核酸组分的分析,阐明乳杆菌DM9811对数生长期培养基滤液中核酸的性质。方法应用核酸的分离、纯化及电泳分析技术。结果乳杆菌对数生长期培养基滤液中核酸组分为RNA,其片段大小为100 bp左右。乳杆菌对数生长期培养基滤液中核酸组分为RNA,为对数期产生且呈时间依赖关系。结论核酸组分不仅仅是遗传信息的载体,还可能作为有效的信息分子。     

Gastric and duodenum microflora analysis after long-term Helicobacter pylori infection in Mongolian Gerbils

Background: Long‐term Helicobacter pylori infection leads to chronic gastritis, peptic ulcer, and gastric malignancies. Indigenous microflora in alimentary tract maintains a colonization barrier against pathogenic microorganisms. This study is aimed to observe the gastric and duodenum microflora alteration after H. pylori infection in Mongolian Gerbils model. Materials and Methods: A total of 18 Mongolian gerbils were randomly divided into two groups: control group and H. pylori group that were given H. pylori NCTC J99 strain intragastrically. After 12 weeks, H. pylori colonization was identified by rapid urease tests and bacterial culture. Indigenous microorganisms in stomach and duodenum were analyzed by culture method. Histopathologic examination of gastric and duodenum mucosa was also performed. Results: Three of eight gerbils had positive H. pylori colonization. After H. pylori infection, Enterococcus spp. and Staphylococcus aureus showed occurrences in stomach and duodenum. Lactobacillus spp. showed a down trend in stomach. The levels and localizations of Bifidobacterium spp., Bacteroides spp., and total aerobes were also modified. Bacteroides spp. significantly increased in H. pylori positive gerbils. No Enterobacteriaceae were detected. Positive colonization gerbils showed a higher histopathologic score of gastritis and a similar score of duodenitis. Conclusions: Long‐term H. pylori colonization affected the distribution and numbers of indigenous microflora in stomach and duodenum. Successful colonization caused a more severe gastritis. Gastric microenvironment may be unfit for lactobacilli fertility after long‐term H. pylori infection, while enterococci, S. aureus, bifidobacteria, and bacteroides showed their adaptations.     

Strain-dependent proliferation in response to human gastric mucin and adhesion properties of Helicobacter pylori are not affected by co-isolated Lactobacillus sp

Background: Helicobacter pylori colonize the mucus layer that covers the gastric epithelium and can cause gastritis, ulcers, and gastric cancer. Recently, Lactobacillus sp. have also been found to reside in this niche permanently. This study compares adhesive properties and proliferation of co‐isolated lactobacilli and H. pylori in the presence of mucins and investigates possibilities for lactobacilli‐mediated inhibition of H. pylori. Materials and methods: Binding and proliferation of four H. pylori and four Lactobacillus strains, simultaneously isolated after residing in the stomachs of four patients for >4 years, to human gastric mucins were investigated using microtiter‐based methods. Results: The H. pylori strains co‐isolated with lactobacilli exhibited the same mucin binding properties as demonstrated for H. pylori strains previously. In contrast, no binding to mucins was detected with the Lactobacillus strains. Proliferation of mucin‐binding H. pylori strains was stimulated by the presence of mucins, whereas proliferation of non‐binding H. pylori and Lactobacillus strains was unaffected. Associative cultures of co‐isolated H. pylori and Lactobacillus strains showed no inhibition of H. pylori proliferation because of the presence of whole bacteria or supernatant of lactobacilli. Conclusions: The presence of lactobacilli in the stomach did not select for different mucin binding properties of H. pylori, and Lactobacillus sp. did neither compete for binding sites nor inhibit the growth of co‐isolated H. pylori. The effects of human gastric mucins on H. pylori proliferation vary between strains, and the host–bacteria interaction in the mucus niche thus depends on both the H. pylori strain and the microenvironment provided by the host mucins.     

Linoleate isomerase activity occurs in lactic acid bacteria strains and is affected by pH and temperature

Aims: To investigate the ability of lactic acid bacteria (LAB) to convert linoleic acid (LA) and α‐linolenic acid (α‐LNA) to conjugated linoleic acid (CLA) and conjugated linolenic acid (CLNA), respectively. To assess pH and temperature influences on CLA and CLNA production by Lactobacillus sakei LMG 13558. Methods and Results: A screening of 48 LAB yielded one Lactobacillus curvatus, five Lactobacillus plantarum and four Lact. sakei strains displaying linoleate isomerase (LAI) activity. CLNA conversion percentages varied largely (1–60%). CLA conversion, occurring in three strains, was lower (2–5%). The LAI gene sequences of the ten LAI‐positive strains shared 75–99% identity with the LAI gene sequence of a Lact. plantarum AS1.555. At pH 6·2, CLA and CLNA production by Lact. sakei LMG 13558 was higher at 30°C than at 20 and 25°C. At pH 5·5 (30°C) or 37°C (pH 6·2), LA was not converted and α‐LNA only slightly converted. Conclusions: LAB show strain‐dependent LAI activity. Production of CLA and CLNA is affected by pH and temperature, as shown for Lact. sakei LMG 13558. Significance and Impact of the Study: Several LAB produce CLA and/or CLNA, as shown for Lact. sakei and Lact. curvatus for the first time. These findings offer potential for the manufacturing of fermented functional foods.     

B-group vitamin production by lactic acid bacteria--current knowledge and potential applications

Although most vitamins are present in a variety of foods, human vitamin deficiencies still occur in many countries, mainly because of malnutrition not only as a result of insufficient food intake but also because of unbalanced diets. Even though most lactic acid bacteria (LAB) are auxotrophic for several vitamins, it is now known that certain strains have the capability to synthesize water-soluble vitamins such as those included in the B-group (folates, riboflavin and vitamin B(12) amongst others). This review article will show the current knowledge of vitamin biosynthesis by LAB and show how the proper selection of starter cultures and probiotic strains could be useful in preventing clinical and subclinical vitamin deficiencies. Here, several examples will be presented where vitamin-producing LAB led to the elaboration of novel fermented foods with increased and bioavailable vitamins. In addition, the use of genetic engineering strategies to increase vitamin production or to create novel vitamin-producing strains will also be discussed. This review will show that the use of vitamin-producing LAB could be a cost-effective alternative to current vitamin fortification programmes and be useful in the elaboration of novel vitamin-enriched products.     

Protective effect of Lactobacillus casei strain Shirota against lethal infection with multi-drug resistant Salmonella enterica serovar Typhimurium DT104 in mice

Aims: The anti‐infectious activity of lactobacilli against multi‐drug resistant Salmonella enterica serovar Typhimurium DT104 (DT104) was examined in a murine model of an opportunistic antibiotic‐induced infection. Methods and Results: Explosive intestinal growth and subsequent lethal extra‐intestinal translocation after oral infection with DT104 during fosfomycin (FOM) administration was significantly inhibited by continuous oral administration of Lactobacillus casei strain Shirota (LcS), which is naturally resistant to FOM, at a dose of 10⁸ colony‐forming units per mouse daily to mice. Comparison of the anti‐Salmonella activity of several Lactobacillus type strains with natural resistance to FOM revealed that Lactobacillus brevis ATCC 14869^T, Lactobacillus plantarum ATCC 14917^T, Lactobacillus reuteri JCM 1112^T, Lactobacillus rhamnosus ATCC 7469^T and Lactobacillus salivarius ATCC 11741^T conferred no activity even when they obtained the high population levels almost similar to those of the effective strains such as LcS, Lact. casei ATCC 334^T and Lactobacillus zeae ATCC 15820^T. The increase in concentration of organic acids and maintenance of the lower pH in the intestine because of Lactobacillus colonization were correlated with the anti‐infectious activity. Moreover, heat‐killed LcS was not protective against the infection, suggesting that the metabolic activity of lactobacilli is important for the anti‐infectious activity. Conclusion: These results suggest that certain lactobacilli in combination with antibiotics may be useful for prophylaxis against opportunistic intestinal infections by multi‐drug resistant pathogens, such as DT104. Significance and Impact of the Study: Antibiotics such as FOM disrupt the metabolic activity of the intestinal microbiota that produce organic acids, and that only probiotic strains that are metabolically active in vivo should be selected to prevent intestinal infection when used clinically in combination with certain antibiotics.     

Structure-function relationships of the antibacterial activity of phenolic acids and their metabolism by lactic acid bacteria

Aims: To determine structure–function relationships of antibacterial phenolic acids and their metabolites produced by lactic acid bacteria (LAB). Methods and Results: Minimum inhibitory concentrations (MICs) of 6 hydroxybenzoic and 6 hydroxycinnamic acids were determined with Lactobacillus plantarum, Lactobacillus hammesii, Escherichia coli and Bacillus subtilis as indicator strains. The antibacterial activity of phenolic acids increased at lower pH. A decreasing number of hydroxyl groups enhanced the activity of hydroxybenzoic acids, but had minor effects on hydroxycinnamic acids. Substitution of hydroxyl groups with methoxy groups increased the activity of hydroxybenzoic, but not of hydroxycinnamic, acid. Metabolism of chlorogenic, caffeic, p‐coumaric, ferulic, protocatechuic or p‐hydroxybenzoic acids by L. plantarum, L. hammesii, Lactobacillus fermentum and Lactobacillus reuteri was analysed by LC‐DAD‐MS. Furthermore, MICs of substrates and metabolites were compared. Decarboxylated and/or reduced metabolites of phenolic acids had a lower activity than the substrates. Strain‐specific metabolism of phenolic acids generally corresponded to resistance. Conclusions: The influence of lipophilicity on the antibacterial activity of hydroxybenzoic acids is stronger than that of hydroxycinnamic acids. Metabolism of phenolic acids by LAB detoxifies phenolic acids. Significance and Impact of the Study: Results allow the targeted selection of plant extracts for food preservation, and selection of starter cultures for fermented products.