Evidence for in vitro anti-genotoxicity of cheese non-starter lactobacilli

The inhibition of direct acting DNA reactive agents by 63 non-starter lactobacilli isolated from raw ewes milk cheeses was examined by short-term assay (SOS-Chromotest) and compared with already characterized starter lactobacilli. The screening revealed strains active against the nitroarene 4-nitroquinoline-1-oxide (NQO) and the alkylating agent N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) in different species of the genus Lactobacillus (L. rhamnosus, L. casei, L. plantarum, L. brevis, Lactobacillus spp.). It was proved that the anti-genotoxicity was strain-dependent, and always associated with spectroscopic modification of genotoxins. The frequency of strains inhibiting nitroarene genotoxicity was comparable for non-starter and starter lactobacilli, whereas inhibition of the alkylating agent was largely predominant in non-starter isolates. Seventeen strains presented inhibitory activity against both genotoxins. DNA RAPD-PCR performed with M13, Pro-Up and RPO2 primers on the lactobacilli under examination showed genetic diversity in these strains. The non-starter isolates clustered in seven groups and the strains presenting a high degree of activity against 4-nitroquinoline-1-oxide clustered in a single group with a similarity around 75%. Interestingly, the strains with anti-genotoxic properties also showed acid-bile tolerance, indicating that the autochthonous lactobacilli which survive cheese ripening may also reach the gut as viable cells and could prevent genotoxin DNA damage to enterocytes, as is desirable for probiotic bacteria.     

Screening for lactobacilli with probiotic properties in the infant gut microbiota

Lactobacilli are believed to be beneficial for the human hosts and are currently being evaluated as potentially probiotic bacteria. In this study, Lactobacillus strains were isolated from infant faeces and were examined in vitro for potential probiotic properties. Faecal specimens from 63 healthy, full-term infants were collected at 4, 30 and 90 days after delivery. Seventy-four Lactobacillus strains were isolated and one or more different phenotypes from each infant (n = 44) were selected for further testing. The bacterial isolates were identified mainly as L. gasseri, L. crispatus, Lactobacillus paracasei, L. salivarius, L. fermentum after amplification and sequencing of 16s rRNA gene. The strains were examined for acid and bile tolerance, adhesion to Caco-2 cells, antibiotic susceptibility and antimicrobial activity against selected enteric pathogens. The great majority of the isolated lactobacilli were susceptible to ampicillin, amoxicillin/clavulanic acid, tetracycline, erythromycin, cephalothin, chloramphenicol and rifampicin. Resistance to vancomycin or bacitracin was detected to 34% of the strains. Twenty strains out of forty-four exhibited significant tolerance to bile salts. Those strains were subsequently tested for resistance to low pH conditions (pH 2 and 3). Interestingly, 85% (17 strains) of the tested lactobacilli remained unaffected at pH 3 after 3 h of incubation, 6 strains were found resistant at pH 2 after 1.5 h and only 2 strains found resistant after 3 h of incubation. Two of the strains were able to adhere to Caco-2 cells. In conclusion, two isolates fulfilled the in vitro probiotic criteria and are good candidates for further in vivo evaluation.     

The probiotic properties and potential of vaginal Lactobacillus spp. isolated from healthy women against some vaginal pathogens

During the last decade, probiotic research has progressed considerably and significant advances have been made in the selection and characterization of specific probiotic strains. The most studied probiotics belong to the genus Lactobacillus. In this study, 80 Lactobacillus spp. isolated from healthy women tolerated low pH and were able to grow in the presence of bile salts. RAPD PCR technique resulted in the identification of 38 different types. These isolates were then evaluated based on adhesion capacity, antibiotic susceptibility and tolerance in simulated gastrointestinal tract. Species-specific PCR and detection of bacteriocin-related genes were also surveyed. Among the isolates, five strains—Lacticaseibacillus rhamnosus NO21, Lacticaseibacillus casei NO1, Lactiplantibacillus plantarum NO4, Lactobacillus acidophilus NO7 and Lactobacillus gasseri NO38—presented acceptable antibiotic susceptibility pattern. Further analysis showed antimicrobial activity of Lacticaseibacillus culture against various bacterial pathogens and real-time PCR showed all five strains were able to prevent the colonization of bacterial pathogens. All five selected strains produced organic acids, hydrogen peroxide and were resistant to the spermicide. In addition, they lacked haemolytic activity with the ability of hydrophobicity, auto-aggregation and co-aggregation with pathogens. These results suggest that the vaginal microbiome could be a good source for the isolation of probiotics and the strains of this study may be considered as good probiotic candidates.     

牦牛源产细菌素屎肠球菌的分离鉴定和益生特性

【背景】抗生素的滥用导致牦牛肠道常见病原菌耐药性增加,益生菌作为对抗耐药性细菌的新型武器,应用前景广阔。【目的】获取益生特性优良的牦牛源益生菌。【方法】将20份牦牛粪便样本在含0.5%CaCO3的MRS培养基上分离纯化,以大肠杆菌和金黄色葡萄球菌为指示菌,用牛津杯法筛选有抑菌活性的菌株;排除酸和过氧化氢后,经耐酸耐热试验和蛋白酶敏感试验筛选产细菌素菌株,用形态学和16S rRNA基因序列分析鉴定;通过对大肠杆菌、沙门氏菌等腹泻病原菌体外抑菌试验、耐模拟胃肠液、测定自聚集能力和疏水性及抗生素敏感试验分析益生特性。【结果】从20份牦牛粪便样本中共分离出11株产生溶钙圈的菌株,其中6株对大肠杆菌和金黄色葡萄球菌抑菌效果显著,经复筛得到2株产细菌素的乳酸菌SC6和SC9,经鉴定均为屎肠球菌(Enterococcus faecium)。其中SC9对腹泻病原菌抑菌效果明显,有良好的耐受性和肠道黏附能力,对5种常用抗生素均敏感。【结论】屎肠球菌SC9有一定的抗逆性和潜在的益生能力,具备作为益生菌的潜力。     

Antagonistic activity of Lactobacillus bacteria strains against anaerobic gastrointestinal tract pathogens (Helicobacter pylori, Campylobacter coli, Campylobacter jejuni, Clostridium difficile)]

Antagonistic activity of Lactobacillus strains has been known for some time. This property is connected with production of many active substances by lactobacilli e.g., organic acids and bacteriocin-like substances which interfere with other indigenous microorganisms inhabiting the same ecological niche, including also anaerobic gastrointestinal tract pathogens. Growing interest of clinical medicine in finding new approaches to treatment and prevention of common inflammatory infections of the digestive tract resulted in studies on a possible usage of lactic acid bacteria. Last years, several in vitro and in vivo experiments on antagonism of different Lactobacillus strains against Helicobacter pylori and Clostridium difficile were performed. These observations had been done on already established, well known probiotic Lactobacillus strains. We tested antibacterial activities of Lactobacillus strains isolated from human digestive tract. As indicator bacteria, four species known as anaerobic bacterial etiologic agents of gastroenteric infections: Helicobacter pylori, Campylobacter jejuni, C. coli and Clostridium difficile were used. Some of them were obtained from international collections, others were clinical isolates from specimens taken from patients with different defined gastrointestinal infections. We used a slab method of testing inhibitory activity described in details previously. Following conclusions were drawn from our study: All tested human Lactobacillus strains were able to inhibit the growth of all strains of anaerobic human gastrointestinal pathogens used in this study. Inhibitory activities of tested Lactobacillus strains against Helicobacter pylori, Campylobacter spp., and Clostridium difficile as measured by comparing mean diameters of the inhibition zones were similar. Differences in susceptibility of individual indicator strains of Campylobacter spp. and Clostridium difficile to inhibitory activity of Lactobacillus strains were small. A similar mechanism of inhibition of anaerobic bacteria by lactobacilli is postulated.     

Antagonistic activity of probiotic lactobacilli and bifidobacteria against entero- and uropathogens

AIM: To develop in vitro assays for comparing the antagonistic properties and anti-oxidative activity of probiotic Lactobacillus and Bifidobacterium strains against various entero- and urinary pathogens. METHODS AND RESULTS: The antagonistic activity of five probiotic lactobacilli (Lactobacillus rhamnosus GG, Lactobacillus fermentum ME-3, Lactobacillus acidophilus La5, Lactobacillus plantarum 299v and Lactobacillus paracasei 8700:2) and two bifidobacteria (Bifidobacterium lactis Bb12, Bifidobacterium longum 46) against six target pathogens was estimated using different assays (solid and liquid media, anaerobic and microaerobic cultivation) and ranked (low, intermediate and high). Bacterial fermentation products were determined by gas chromatography, and the total anti-oxidative activity of probiotics was measured using linolenic acid test. Pyelonephritic Escherichia coli was highly suppressed by GG and both bifidobacteria strains. Lactobacilli strains 8700:2, 299v and ME-3 were the most effective against Salmonella enterica ssp. enterica in microaerobic while ME-3 and both bifidobacteria expressed high activity against Shigella sonnei in anaerobic milieu. Lact. paracasei, Lact. rhamnosus and Lact. plantarum strains showed intermediate antagonistic activity against Helicobacter pylori under microaerobic conditions on solid media. The highest anti-oxidative activity was characteristic for Lact. fermentum ME-3 (P < 0.05). No efficient antagonist against Clostridium difficile was found. The positive correlations between the pH, lactic acid production and anti-microbial activity for all tested probiotics were assessed. CONCLUSIONS: Developed experimental assays enable to compare the anti-microbial and -oxidative activity of Lactobacillus and/or Bifidobacterium probiotics, which have been claimed to possess the ability of suppressing the growth of various enteric and urinary pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: Screening Lactobacillus and Bifidobacterium sp. strains according to their activity in various environmental conditions could precede the clinical efficacy studies for adjunct treatment with probiotics in cure of different gastrointestinal and urinary tract infections.     

Influence of cell surface properties on adhesion ability of bifidobacteria

Adhesion ability of bifidobacteria to the intestinal mucosa is considered to be the prerequisite for colonization of bifidobacteria and can protect against gastrointestinal pathogens infection. The aim of this study was to investigate bifidobacterial surface traits related to adhesion ability in vitro and characterize the cell surface substances that may be involved in the adhesion process of bifidobacteria. Twelve strains of Bifidobacterium spp. were studied for the correlation among their adhesion ability, autoaggregation ability and surface hydrophobicity. The strain that exhibited good adhesion ability also showed high degree of hydrophobicity and strong autoaggregation ability. Pepsin treatment had negative effect on the surface traits and adhesion ability of B. bifidum KLDS2.0603 (P < 0.01), it revealed that hydrophobicity, autoaggregation and adhesion process maybe mediated by proteinaceous components on the surface of cell. Moreover, the adhesion and autoaggregation ability decreased after extraction of B. bifidum KLDS2.0603 with 5 mol l⁻¹ LiCl, and an unreported 50-kDa surface protein which can bind to Caco-2 cell was observed by western blotting. Our results indicated that surface hydrophobicity and autoaggregation ability can be used together for preliminary screening the strains with high adhesion ability, and the present of the surface proteinaceous components would contribute to understand the interactions between bifidobacteria and human intestinal mucosa.     

Toward an Alternative Therapeutic Approach for Skin Infections: Antagonistic Activity of Lactobacilli Against Antibiotic-Resistant Staphylococcus aureus and Pseudomonas aeruginosa

The wide spread of antimicrobial resistance has urged the need of alternative therapeutic approach. In this context, probiotic lactobacilli have been reported for the prevention and treatment of many gastrointestinal and urogenital infections. However, very little is known about their antagonistic activity against skin pathogens. Accordingly, the present study aimed to investigate the potential of lactobacilli to interfere with pathogenesis features of two antibiotic-resistant skin pathogens, namely methicillin-resistant Staphylococcus aureus and multiple-resistant Pseudomonas aeruginosa. A total of 49 lactobacilli were recovered, identified and tested for their antagonistic activities against the aforementioned pathogens. Of these, eight isolates were capable of blocking the adherence of pathogens to mammalian cells independent of the skin pathogen tested or model adopted. Moreover, three Lactobacillus isolates (LRA4, LC2 and LR5) effectively prevented the pathogen internalization into epithelial cells in addition to potentiating phagocyte-mediated pathogen killing. Interestingly, the lactobacilli LC2, LF9 and LRA4 markedly inhibited the growth of P. aeruginosa and S. aureus isolates in coculture experiments. Besides, the lactobacilli LRA4, LC2, LR5 and LF9 have counteracted pathogen cytotoxicity. Taken together, the present study revealed some inhibitory activities of lactobacilli against two antibiotic-resistant skin pathogens. Moreover, it revealed two lactobacilli, namely LC2 and LRA4, with antagonistic capacity against different virulence determinants of skin pathogens. These lactobacilli are considered promising probiotic candidates that may represent an alternative therapeutic approach for skin infections.     

Selection of Potential Probiotic Bacteria from Exclusively Breastfed Infant Faeces with Antagonistic Activity Against Multidrug-Resistant ESKAPE Pathogens

The past decade has brought a significant rise in antimicrobial resistance, and the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) have considerably aggravated a threat to public health, causing nosocomial infections worldwide. The objective of the current study was to isolate novel probiotic strain with antimicrobial activity against multidrug-resistant ESKAPE pathogens. For this purpose, eighteen breastfed infant faeces were collected and lactic acid bacteria (LAB) with antagonistic activity were isolated. Out of 102 anaerobic LAB isolated, only nine exhibited inhibitory activity against all ESKAPE pathogens. These selected nine isolates were further characterized for their probiotic attributes such as lysozyme tolerance, simulated gastrointestinal tolerance, cellular auto-aggregation and cell surface hydrophobicity. Bile salt deconjugation and cholesterol-lowering capacity was also determined. Among all nine, isolate LBM220 was found to possess superior probiotic potential. Confirmatory identification of isolate LBM220 was done by both 16S rRNA sequence analysis and mass spectrometric analysis using MALDI-TOF. Based on BLAST result, isolate LBM220 was identified as Lactobacillus gasseri. Phylogenetic analysis of Lactobacillus gasseri LBM220 [accession number MN097539] was performed. Also, detailed safety evaluation study of Lact. gasseri LBM220 showed the presence of intrinsic antibiotic resistance and the absence of hemolytic, DNase, gelatinase and toxic mucinolytic activity. Time kill assay was also performed to confirm the strong kill effect of Lact. gasseri LBM220 on all six multidrug resistant ESKAPE pathogens. Thus, Lact. gasseri LBM220 can be utilized and explored as potential probiotic with therapeutic intervention.

     

Characterization of the beneficial properties of lactobacilli isolated from bullfrog (<Emphasis Type="Italic">Rana catesbeiana</Emphasis>) hatchery

The present work addresses the isolation and partial identification of the microbial population of a R. catesbeiana hatchery in spring and summer as well as some beneficial properties of Lactobacillus strains isolated in different seasons and hatchery areas. The bacterial population was grouped into the following taxa: Lactobacillus spp., Pediococcus spp., Enterococcus faecalis and Ent. faecium, and Enterobacteriaceae (Enterobacter spp., Escherichia coli) while Pseudomonas aeruginosa and Staphylococcus epidermidis were isolated from frogs displaying red-leg syndrome. The Lactobacillus plantarum and L. curvatus strains isolated showed to inhibit the growth of red-leg syndrome associated pathogens and food-borne bacteria by organic acids. While L. plantarum CRL 1606 also inhibited red-leg syndrome related pathogens by hydrogen peroxide, meat spoilage bacteria were only inhibited by acidity. However, by using a MRS medium added with tetramethyl-benzidine and peroxidase, a high percentage of H₂O₂-producing lactobacilli were detected. The surface properties of Lactobacillus strains showed that a few strains were able to agglutinate ABO human erythrocytes, while the highest number of strains had a low to medium degree of hydrophobicity. This paper constitute the first study related to the beneficial properties of Lactobacillus isolated from a bullfrog hatchery, as well as the selection criteria applied to a group of strains, which could help to control or prevent bacterial infectious diseases in raniculture.     

Survival of bifidobacteria administered to calves

Twenty-five bifidobacteria were isolated from feces of calves. Isolates were identified, and their functional properties and antimicrobial activity were determined. From 10 strains with suitable properties rifampicin-resistant mutants (RRBs) were prepared and mixture of RRBs was administered to 2-d-old calves. These strains were identified by sequencing as Bifidobacterium animalis ssp. animalis (6 strains), B. thermophilum (2 strains), B. choerinum (1 strain) and B. longum ssp. suis (1 strain). The control group was without probiotic treatment. Survival ability of administered bifidobacteria was monitored in fecal samples by cultivation on modified TPY agar supplemented with mupirocin, acetic acid, and rifampicin. Administered bifidobacteria survived in gastrointestinal tract of calves for at least 60 d. Other bacteria were also determined after cultivation using fluorescence in situ hybridization (FISH). Bifidobacteria and lactobacilli dominated in fecal microflora. Significantly lower amounts of E. coli and higher amounts of bifidobacteria and total anaerobes were found in the treated group relative to the control group.     

Identification of Vaginal Lactobacilli with Potential Probiotic Properties Isolated from Women in North Lebanon

The aim of this work was to study the diversity of vaginal lactobacilli in Lebanese women and to evaluate the antagonism, hydrophobicity, and safety characteristics of these strains. This study was performed on samples from 135 women who visited a gynecology clinic in the north of Lebanon, between September 2012 and January 2013. From these samples, 53 different isolates of vaginal lactobacilli were collected from vaginal swabs and identified using biochemical and molecular methods. The use of genotypic Rep-PCR fingerprinting allowed for the organization of these isolates into 23 different groups. Seven of the isolated lactobacilli were antagonistic against the following vaginal pathogens: Gardnerella vaginalis CIP7074T, Staphylococcus aureus ATCC33862, Escherichia coli CIP103982, and Candida albicans ATCC10231. The antagonistic lactobacilli strains were then identified using 16S rDNA sequence. The data of this study show that the antagonistic lactobacilli were non-hemolytic, sensitive to most antibiotic tests, free of plasmid DNA, and exhibited interesting hydrophobicity and autoaggregation properties positioning them as potential candidates for probiotic design.     

In vitro inhibitory activity of human vaginal lactobacilli against pathogenic bacteria associated with bacterial vaginosis in Kenyan women

Lactobacilli have been shown to inhibit in vitro growth of many pathogens and have been used as probiotics to treat a broad range of gastrointestinal and/or vaginal disorders. We sought to determine the in vitro inhibitory potential of lactobacilli of vaginal origin to some bacteria associated with bacterial vaginosis (BV), to characterize the inhibitory substances produced by these lactobacilli and to assess H₂O₂ production. Vaginal specimens were obtained by swabbing the lateral vaginal walls from 107 women two months following BV treatment. One hundred and fifty eight Lactobacillus spp. were isolated in 82 of the 107 women. Lactobacillus jensenii was the predominant strain isolated among these women (29/158; 18.4%). Among 158 culture supernatants tested for antibacterial activity against BV-associated bacteria, none inhibited the growth of Bacteroides fragilis while 23% (37/158), 28% (45/158) and 29% (46/158) inhibited the growth of Prevotella bivia, Gardnerella vaginalis and Mobiluncus spp. respectively. The lactobacilli produced supernatants with a pH range between 2.62 and 6.71; the highly acidic (pH 2–3.99) supernatants were more inhibitory to the indicator strains. There was significant reduction in the mean zones of inhibition following chemical and physical treatment of the supernatants (p = 0.0025). Acid, bacteriocins and H₂O₂ demonstrated potential for antagonism of the bacterial pathogens. These substances may augment each other rather that each working independently on the pathogens.     

An in vitro protocol for direct isolation of potential probiotic lactobacilli from raw bovine milk and traditional fermented milks

A method for isolating potential probiotic lactobacilli directly from traditional milk-based foods was developed. The novel digestion/enrichment protocol was set up taking care to minimize the protective effect of milk proteins and fats and was validated testing three commercial fermented milks containing well-known probiotic Lactobacillus strains. Only probiotic bacteria claimed in the label were isolated from two out of three commercial fermented milks. The application of the new protocol to 15 raw milk samples and 6 traditional fermented milk samples made it feasible to isolate 11 potential probiotic Lactobacillus strains belonging to Lactobacillus brevis, Lactobacillus fermentum, Lactobacillus gasseri, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus reuteri, and Lactobacillus vaginalis species. Even though further analyses need to ascertain functional properties of these lactobacilli, the novel protocol set-up makes it feasible to isolate quickly potential probiotic strains from traditional milk-based foods reducing the amount of time required by traditional procedures that, in addition, do not allow to isolate microorganisms occurring as sub-dominant populations.     

Isolation and characterization of bacteriocin‐producing bacteria from the gastrointestinal tract of broiler chickens for probiotic use

Aims: To isolate and characterize the bacteriocin‐producing bacteria (BPB) from the gastrointestinal tract of broiler chickens for probiotic use. Methods and Results: In total, 291 bacterial strains were isolated from broilers and screened for bacteriocin‐producing ability. The bacteriocins produced by Enterococcus faecium SH 528, Ent. faecium SH 632 and Pediococcus pentosaceus SH 740 displayed inhibitory activity against pathogens including Clostridium perfringens and Listeria monocytogenes. Activity of the bacteriocins remained unchanged after 30 min of heat treatment at 60°C or exposure to organic solvents, but diminished after treatment with proteolytic enzymes. PCR was used to detect the structural genes enterocin A and B in SH 528, enterocin L50 and P in SH 632, and pediocin PA‐1 in SH 740. Most of them were resistant to 0·5% bile salts and remained viable after 2 h at pH 3·0. Ent. faecium SH 528 exhibited the highest amylase activity among the strains tested. Conclusions: We selected Ent. faecium SH 528 and SH 632 and Ped. pentosaceus SH 740 by probiotic selection criteria including inhibition activity against pathogens. Significance and Impact of the Study: The isolated BPB could potentially be used in the poultry industry as probiotics to control pathogens.     

In vitro screening of probiotic lactic acid bacteria and prebiotic glucooligosaccharides to select effective synbiotics

Probiotics and prebiotics have been demonstrated to positively modulate the intestinal microflora and could promote host health. Although some studies have been performed on combinations of probiotics and prebiotics, constituting synbiotics, results on the synergistic effects tend to be discordant in the published works. The first aim of our study was to screen some lactic acid bacteria on the basis of probiotic characteristics (resistance to intestinal conditions, inhibition of pathogenic strains). Bifidobacterium was the most resistant genus whereas Lactobacillus farciminis was strongly inhibited. The inhibitory effect on pathogen growth was strain dependent but lactobacilli were the most effective, especially L. farciminis. The second aim of the work was to select glucooligosaccharides for their ability to support the growth of the probiotics tested. We demonstrated the selective fermentability of oligodextran and oligoalternan by probiotic bacteria, especially the bifidobacteria, for shorter degrees of polymerisation and absence of metabolism by pathogenic bacteria. Thus, the observed characteristics confer potential prebiotic properties on these glucooligosaccharides, to be further confirmed in vivo, and suggest some possible applications in synbiotic combinations with the selected probiotics. Furthermore, the distinctive patterns of the different genera suggest a combination of lactobacilli and bifidobacteria with complementary probiotic effects in addition to the prebiotic ones. These associations should be further evaluated for their synbiotic effects through in vitro and in vivo models.     

In Vitro Evaluation of the Probiotic Potential of Halotolerant Lactobacilli Isolated from a Ripened Tropical Mexican Cheese

Three halotolerant lactobacilli (Lactobacillus plantarum, L. pentosus, and L. acidipiscis) isolated from a ripened Mexican tropical cheese (double cream Chiapas cheese) were evaluated as potential probiotics and compared with two commercial probiotic strains (L. casei Shirota and L. plantarum 299v) from human origin. All the strains survived the in vitro gastrointestinal simulation from the oral cavity to the ileum. During the stomach simulation, all the strains survived in satiety conditions (60 min, pH 3.0, 3 g/L pepsin, 150 rpm) and only L. pentosus could not survive under fasting conditions (60 min, pH 2.0, 3 g/L pepsin, 150 rpm). All the strains showed a strong hydrophilic character with low n-hexadecane and a variable chloroform affinity. L. plantarum showed a mucin adhesion rate similar to that of L. plantarum 299v and L. casei Shirota, while L. pentosus and L. acidipiscis had a lower mucin adhesion. The isolated halotolerant lactobacilli exhibited similar antimicrobial activity against some gram-positive and gram-negative pathogens in comparison with the two commercial strains. In addition, the proteinaceous character of the antimicrobial agents against the most pathogenic strains was demonstrated. The compounds showed a low molecular weight (less than 10 kDa). Besides, L. plantarum and L. acidipiscis were able to produce the enzyme β-galactosidase. Finally, L. pentosus was able to deconjugate taurocholic, taurodeoxycholic, glycocholic, and glycodeoxycholic acids better than the two commercial strains analyzed. All these results suggest that the halotolerant lactobacilli isolated from this ripened Mexican cheese could be potentially probiotic. This is the first time that halotolerant lactic acid bacteria have been shown to have probiotic properties.     

Dermal bioactives from lactobacilli and bifidobacteria

Lactobacilli and bifidobacteria are the most common genera of probiotics with documented potentials on gut health. Recent studies have suggested that such potentials can be extended beyond gut well-being, such as that of dermal health. Our present study aimed to evaluate the production of bioactives that are essential for skin defense, such as lipoteichoic acid, peptidoglycan, hyaluronic acid, sphingomyelinase, lactic acid, acetic acid, and diacetyl, from lactobacilli and bifidobacteria grown in milk. All strains studied showed the presence of LTA in the cell wall fraction, with higher amounts from Lactobacillus rhamnosus FTDC 8313 and Bifidobacterium longum BL 8643 than other strains studied. Meanwhile, all strains studied showed equal concentrations of cell wall peptidoglycan. Our results showed that all strains studied were capable of producing hyaluronic acid, with higher production by lactobacilli than bifidobacteria. Production of diacetyl was more prevalent from strains of lactobacilli, while bifidobacteria produced higher amounts of acetic acid. Strains of lactobacilli and bifidobacteria studied also produced acid and neutral sphingomyelinase, an enzyme that generates ceramides and subsequent development of physical barriers in the stratum corneum. Our current findings show that bioactive and inhibitive extracts are produced from the fermentation of lactobacilli and bifidobacteria in milk, with potentials for dermal applications.     

Boza, a natural source of probiotic lactic acid bacteria

Aims: To evaluate the probiotic properties of strains isolated from boza, a traditional beverage produced from cereals. Methods and Results: The strains survived low pH conditions (pH 3·0), grew well at pH 9·0 and were not inhibited by the presence of 0·3% (w/v) oxbile. Cytotoxicity levels of the bacteriocins, expressed as CC₅₀, ranged from 38 to 3776 μg ml^?1. Bacteriocin bacST284BZ revealed high activity (EC₅₀ = 735 μg ml^?1) against herpes simplex virus type 1. Growth of Mycobacterium tuberculosis was 69% repressed after 5 days in the presence of bacST194BZ. Various levels of auto‐cell aggregation and co‐aggregation with Listeria innocua LMG 13568 were observed. Adhesion of the probiotic strains to HT‐29 cells ranged from 18 to 22%. Conclusions: Boza is a rich source of probiotic lactic acid bacteria. All strains survived conditions simulating the gastrointestinal tract and produced bacteriocins active against a number of pathogens. Adherence to HT‐29 and Caco‐2 cells was within the range reported for Lactobacillus rhamnosus GG, a well‐known probiotic. In addition, the high hydrophobicity readings recorded define the strains as good probiotics. Significance and Impact of the Study: Boza contains a number of different probiotic lactic acid bacteria and could be marketed as a functional food product.