Identification and phylogenetic analysis of Lactobacillus using multiplex RAPD-PCR

Multiplex RAPD-PCR was used to generate unique and identifying DNA profiles for isolates of the genus Lactobacillus. The method that was used was based on the combination of two 10-mer oligonucleotides in a single PCR. The generated RAPD profiles enabled discrimination of all lactobacillus strains that were used in this study. A dendrogram was generated from the RAPD profiles. The results of genetic relatedness obtained from the dendrogram were compared with the results obtained using carbohydrate fermentation profiles. Most of the gastrointestinal isolates studied could not be grouped using carbohydrate fermentation profiles. The RAPD profiles provided sufficient information to prepare a dendrogram of genetic relatedness. The gastrointestinal isolates were clustered together on the dendrogram. Furthermore an isolate originating from the stomach (strain ML004) was closely related to Lactobacillus fermentum. It was concluded that multiplex RAPD-PCR was useful for characterisation and inference of relatedness of Lactobacillus isolates.     

Cloning and characterization of a bile salt hydrolase (<Emphasis Type="Italic">bsh</Emphasis>) from <Emphasis Type="Italic">Bifidobacterium adolescentis</Emphasis>

A gene coding for bile salt hydrolase (BSH) from Bifidobacterium adolescentis was cloned and expressed in Escherichia coli, and the nucleotide sequence was determined. The BSH of E. coli transformants was produced intracellularly in the absence of bile salts. A unique bsh promoter (P_bsh) sequence was identified by using a Neural Network Promoter Prediction (NNPP, version 2.2). In spite of their high-level sequence homology with other bsh genes in the Bifidobacterium species, their genetic organization surrounding the bsh gene and their promoter sequences are different depending on the species.     

Identification and probiotic properties of lactobacilli isolated from two different fermented beverages

Purpose

Scientific information regarding the microbial content and functional aspects of fermented beverages traditionally produced in certain parts of Europe are scarce. However, such products are believed to have some health benefits and might contain functional bacterial strains, such as probiotics. The aim of the study was to identify such lactic acid bacteria strains isolated from water kefir and, for the first time, from braga, a Romanian fermented beverage made of cereals.

Methods

Lactic acid bacteria (LAB) were identified to species level based on (GTG)₅-PCR fingerprinting and 16S rRNA gene sequencing. Selected strains were screened for their antibacterial activity and probiotic potential.

Results

Eight isolates belonging to seven Lactobacillus species were recovered from the two drinks. The identification of LAB involved in the fermentation of braga (Lactobacillus plantarum, Lactobacillus fermentum, and Lactobacillus delbrueckii) is firstly reported here. Five of the Lactobacillus isolates showed antibacterial activity against pathogenic bacteria, including Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Salmonella enterica. Moreover, most of them showed a good resistance to pH 2.5 and some survived at high concentrations of bile salts (up to 2%). Two L. plantarum isolates were able to inhibit all the indicator strains, and showed the best viability (about 70%) after a sequential treatment simulating the passage through the gastrointestinal tract.

Conclusion

Based on the results, the most promising candidates for designing new probiotic products are: L. plantarum BR9 from braga and L. plantarum CR1 from water kefir.

     

Molecular identification of vaginal lactobacilli isolated from Bulgarian women

Lactobacilli play an important role in maintaining the vaginal health of women. The development of suitable bacterial replacement therapies for the treatment of vaginosis requires knowledge of the vaginal lactobacilli species representation. The aim of this study was to identify at the species level vaginal Lactobacillus isolates obtained from Bulgarian women in childbearing age by using different molecular methods. Twenty-two strains of lactobacilli isolated from vaginal samples were identified and grouped according to their genetic relatedness. A combined approach, which included amplified ribosomal DNA restriction analysis (ARDRA), ribotyping and polymerase chain reaction (PCR) with species-specific oligonucleotide primers was applied. All vaginal isolates were grouped into 5 clusters in␣comparison with a set of 21 reference strains based␣on the initial ARDRA results, which was then confirmed by ribotyping. Finally, the strains were subjected to PCR analysis with eight different species-specific primer pairs, which allowed most of␣them to be classified as belonging to one of␣the␣following species: Lactobacillus crispatus, Lactobacillus fermentum, Lactobacillus gasseri, Lactobacillus helveticus and Lactobacillus plantarum. In conclusion, this study suggests that the most straightforward identification strategy for vaginal lactobacilli would be grouping by ARDRA or ribotyping, followed by PCR specific primers identification at species level.     

Probiotic Lactobacillus sp. inhibit growth,biofilm formation and gene expression of caries‐inducing Streptococcus mutans

Streptococcus mutans contributes significantly to dental caries, which arises from homoeostasic imbalance between host and microbiota. We hypothesized that Lactobacillus sp. inhibits growth, biofilm formation and gene expression of Streptococcus mutans. Antibacterial (agar diffusion method) and antibiofilm (crystal violet assay) characteristics of probiotic Lactobacillus sp. against Streptococcus mutans (ATCC 25175) were evaluated. We investigated whether Lactobacillus casei (ATCC 393), Lactobacillus reuteri (ATCC 23272), Lactobacillus plantarum (ATCC 14917) or Lactobacillus salivarius (ATCC 11741) inhibit expression of Streptococcus mutans genes involved in biofilm formation, quorum sensing or stress survival using quantitative real‐time polymerase chain reaction (qPCR). Growth changes (OD600) in the presence of pH‐neutralized, catalase‐treated or trypsin‐treated Lactobacillus sp. supernatants were assessed to identify roles of organic acids, peroxides and bacteriocin. Susceptibility testing indicated antibacterial (pH‐dependent) and antibiofilm activities of Lactobacillus sp. against Streptococcus mutans. Scanning electron microscopy revealed reduction in microcolony formation and exopolysaccharide structural changes. Of the oral normal flora, L. salivarius exhibited the highest antibiofilm and peroxide‐dependent antimicrobial activities. All biofilm‐forming cells treated with Lactobacillus sp. supernatants showed reduced expression of genes involved in exopolysaccharide production, acid tolerance and quorum sensing. Thus, Lactobacillus sp. can inhibit tooth decay by limiting growth and virulence properties of Streptococcus mutans.     

Characterization of Probiotic Properties of Antifungal Lactobacillus Strains Isolated from Traditional Fermenting Green Olives

The aim of this work is to characterize the potential probiotic properties of 14 antifungal Lactobacillus strains isolated from traditional fermenting Moroccan green olives. The molecular identification of strains indicated that they are composed of five Lactobacillus brevis, two Lactobacillus pentosus, and seven Lactobacillus plantarum. In combination with bile (0.3%), all the strains showed survival rates (SRs) of 83.19–56.51% at pH 3, while 10 strains showed SRs of 31.67–64.44% at pH 2.5. All the strains demonstrated high tolerance to phenol (0.6%) and produced exopolysaccharides. The autoaggregation, hydrophobicity, antioxidant activities, and surface tension value ranges of the strains were 10.29–41.34%, 15.07–34.67%, 43.11–52.99%, and 36.23–40.27 mN/m, respectively. Bacterial cultures exhibited high antifungal activity against Penicillium sp. The cell-free supernatant (CFS) of the cultures showed important inhibition zones against Candida pelliculosa (18.2–24.85 mm), as well as an antibacterial effect against some gram-positive and gram-negative bacteria (10.1–14.1 mm). The neutralized cell-free supernatant of the cultures displayed considerable inhibitory activity against C. pelliculosa (11.2–16.4 mm). None of the strains showed acquired or horizontally transferable antibiotic resistance or mucin degradation or DNase, hemolytic, or gelatinase activities. Lactobacillus brevis S82, Lactobacillus pentosus S75, and Lactobacillus plantarum S62 showed aminopeptidase, β-galactosidase, and β-glucosidase activities, while the other enzymes of API-ZYM were not detected. The results obtained revealed that the selected antifungal Lactobacillus strains are considered suitable candidates for use both as probiotic cultures for human consumption and for starters and as biopreservative cultures in agriculture, food, and pharmaceutical industries.

     

Lactobacillus and Pediococcus species richness and relative abundance in the vagina of rhesus monkeys (Macaca mulatta)

Background The rhesus monkey is an important animal model to study human vaginal health to which lactic acid bacteria play a significant role. However, the vaginal lactic acid bacterial species richness and relative abundance in rhesus monkeys is largely unknown. Methods Vaginal swab samples were aseptically obtained from 200 reproductive‐aged female rhesus monkeys. Following Rogosa agar plating, single bacterial colonies representing different morphotypes were isolated and analyzed for whole‐cell protein profile, species‐specific polymerase chain reaction, and 16S rRNA gene sequence. Results A total of 510 Lactobacillus strains of 17 species and one Pediococcus acidilactici were identified. The most abundant species was Lactobacillus reuteri, which colonized the vaginas of 86% monkeys. Lactobacillus johnsonii was the second most abundant species, which colonized 36% of monkeys. The majority of monkeys were colonized by multiple Lactobacillus species. Conclusions The vaginas of rhesus monkeys are frequently colonized by multiple Lactobacillus species, dominated by L. reuteri.     

Inhibitory effect of oral Lactobacillus against oral pathogens

Aims: To determine the inhibitory effect of oral Lactobacillus against putative oral pathogens. Methods and Results: Total 357 strains comprising 10 species of oral Lactobacillus, Lactobacillus fermentum (195), Lactobacillus salivarius (53), Lactobacillus casei (20), Lactobacillus gasseri (18), Lactobacillus rhamnosus (14), Lactobacillus paracasei (12), Lactobacillus mucosae (12), Lactobacillus oris (12), Lactobacillus plantarum (11) and Lactobacillus vaginalis (10) were used as producer strains. Inhibitory effect against a panel of indicators, periodontitis‐ and caries‐related pathogens, was assessed. Most oral Lactobacillus was able to inhibit the growth of both periodontitis‐ and caries‐related pathogens. The strongest inhibitory activity was associated with Lact. paracasei, Lact. plantarum, Lact. rhamnosus, Lact. casei and Lact. salivarius. Lactobacillus SD1–SD6, representing the six species with the strong inhibitory effect, inhibited growth of Streptococcus mutans ATCC 25175 in the biofilm model. Also, it was demonstrated that growth of Strep. mutans was inhibited in a mixture with Lact. paracasei SD1. The inhibition was enhanced in acidic condition and 5% glucose. Conclusions: The results have shown that oral Lactobacillus SD1–SD6 showed a strong inhibitory effect against Strep. mutans and Streptococcus sobrinus, as well as, Gram‐negative periodontal pathogens Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Significance and Impact of the Study: The results indicated that Lactobacillus may be of benefit as probiotics for the prevention of oral diseases.     

Assessment of Lactobacillus species colonizing the vagina of apparently healthy Nigerian women, using PCR-DGGE and 16S rRNA gene sequencing

The identity of lactobacilli colonizing Africa-American women, have previously been based on culture-dependent methods. This led to some misleading speculations that black women lack lactobacilli in their vagina and are therefore highly susceptible to Bacterial vaginosis and STDs including HIV. In this study we used culture-independent procedures.About 241 vaginal swabs were obtained from ‘apparently’ healthy premenopausal women, between 18 and 48 years. Samples were Gram stained for the Nugent score evaluation. DNA was extracted from the bacteria on the vaginal swabs and amplified using polymerase chain reaction (PCR), with Lactobacillus primers. Samples with PCR products were separated with denaturing gradient gel electrophoresis (DGGE) and cut bands were re-amplified with Lactobacillus primers without the GC clamp. The re-amplified product was purified and sequenced with ABI PRISM Big-Dye Terminator. The sequence was identified with BLAST algorithm having the highest Gene Bank Accession number.Out of the 241 vaginal swab samples, 207 (85.8%) had PCR products, indicating the presence of lactobacilli, while 34 (14.2%) showed absence of lactobacilli and the Nugent scores were synonymous to either intermediate bacterial vaginosis or bacterial vaginosis (BV). Out of the 207 samples that had PCR product for Lactobacillus, 149 (72%) had sequence results as revealed by the BLAST algorithm. Most of the women (64%) were colonized by Lactobacillus iners as the predominant strain. Lactobacillus gasseri had 7.3%, followed by L. plantarum and L suntoryeus (6.0%) each. Others were colonized by Lactobacillus crispatus (3.0%), Lactobacillus rhamnosus (2.7%), Lactobacillus vaginalis (2.7%), Lactobacillus rennanqilfy (2.7%), followed by Lactobacillus fermentum (1.3%), Lactobacillus helveticus (1.3%), Lactobacillus johnsonii (1.3%) and Lactobacillus salivarus (1.3%). To our knowledge, this is the first report of Lactobacillus iners being the predominant species colonizing the vagina of the Nigerian women examined. This finding is in line with those from a recent study conducted among Canadian and Swedish women.     

Cloning and sequence analysis of bile salt hydrolase (bsh) gene from Bifidobacterium longum

A pair of PCR primers for the rapid detection of bile salt hydrolase (bsh) gene from Bifidobacterium longum BB536 has been synthesised and have revealed the bsh gene of approx 970 bp in Bifidobacterium longum BB 536 but not in other species of bacteria tested. The bsh gene was cloned and sequenced showing a high similarity to bsh gene previously published. The resulting nucleotide sequence encodes a predicted protein of 317 amino acids, Mw = 35 kDa.     

The effects of Lactobacillus-fermented milk on lipid metabolism in hamsters fed on high-cholesterol diet

The objective of this study was to evaluate the effects of local Lactobacillus strains (NTU 101 and 102) on cholesterol-lowering effects in vivo. Thirty male hamsters were housed, divided into five groups, and fed on a cholesterol diet (5 g/kg diet) to induce hypercholesterolemia. Milk fermented by Lactobacillus paracasei subsp. paracasei NTU 101, Lactobacillus plantarum NTU 102, and Lactobacillus acidophilus BCRC 17010 was administrated for this study. After treatment with different fermented milk, blood was taken and liver was removed for the determination of lipoproteins, including total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride. Lactobacilli and bifidobacteria decreased (10⁵) in the control group; when hamsters were fed on fermented milk, the number of lactobacilli (10⁷–10⁸) and bifidobacteria (10⁵–10⁷) was increased. Serum and liver total cholesterol levels were significantly reduced by about 26.4, 23.5, and 30.1% and by about 17.7, 15.9, and 13.4% when hamsters were given fermented milk. However, serum HDL-C and LDL-C were also reduced. The results of this study showed that the hypocholesterolemic effect of local Lactobacillus strains was attributed to its ability to lower serum and liver total cholesterol levels. Thus, local Lactobacillus strains could significantly increase probiotic count.     

Evaluation of Numerical Analysis of Random Amplified Polymorphic DNA (RAPD)-PCR as a Method to Differentiate Lactobacillus plantarum and Lactobacillus pentosus

Lactobacillus plantarum and Lactobacillus pentosus grouped into one protein profile cluster at r ≥ 0.70, separate from Lactobacillus casei, Lactobacillus sake, and Lactobacillus curvatus. Similar sugar fermentation reactions were recorded for representative strains of L. plantarum and L. pentosus. Representative strains, including the type of each species, were selected from the different protein profile clusters and their genetic relatedness determined by using numerical analysis of random amplified polymorphic DNA (RAPD)-PCR. The type strains of L. plantarum (ATCC 14917^T) and L. pentosus (NCFB 363^T) displayed different RAPD profiles and grouped into two independent clusters, well separated from L. casei, L. curvatus, and L. sake. Numerical analysis of RAPD-PCR proved a reliable and accurate method to distinguish between strains of L. plantarum and L. pentosus.     

Protective Effect of the Intracellular Content from Potential Probiotic Bacteria against Oxidative Damage Induced by Acrylamide in Human Erythrocytes

The aim of this study was to assess the protective effect of the intracellular content obtained from potential probiotic bacteria against acrylamide-induced oxidative damage in human erythrocytes. First, the antioxidant properties of 12 potential probiotic strains was evaluated. Two commercial probiotic bacteria were included as reference strains, namely, Lactobacillus casei Shirota and Lactobacillus paracasei 431. Data showed that the intracellular content from four strains, i.e., Lactobacillus fermentum J10, Lactobacillus pentosus J24 and J26, and Lactobacillus pentosus J27, showed higher (P < 0.05) antioxidant capacity in most methods used. Thereafter, the intracellular content of such pre-selected strains was able to prevent the disturbance of the antioxidant system of human erythrocytes exposed to acrylamide, thereby reducing cell disruption and eryptosis development (P < 0.05). Additionally, the degree of oxidative stress in erythrocytes exposed to acrylamide was significantly (P < 0.05) reduced to levels similar to the basal conditions when the intracellular content of Lact. fermentum J10, Lact. pentosus J27, and Lact. paracasei 431 were employed. Hence, our findings suggest that the intracellular contents of specific Lactobacillus strains represent a potential source of metabolites with antioxidant properties that may help reduce the oxidative stress induced by acrylamide in human erythrocytes.

     

Genetic input by Posidonia oceanica (L.) Delile fruits dispersed by currents in the Ligurian Sea

Abstract

An external genetic input of Posidonia oceanica fruits dispersed by currents in the Ligurian Sea (Western Mediterranean) was investigated. During 2003–2004, when a massive fruiting event occurred, fruits were collected from plants at Monterosso al Mare (meadow) and compared with stranded fruits sampled in front of the meadow and downcurrent in Tuscany along 80 km of the coast. After their growth in culture, the plants were analysed using 10 random amplified polymorphic DNA (RAPD) molecular markers. Cluster analysis of similarity showed four distinct genetic populations. One group included parental plants from Monterosso and stranded fruits with the same genetic traits. The second group was formed by fruits stranded in the southern sector (Tuscany), and the third and the fourth groups were samples taken onshore, in front of the meadow, which appeared very different from the other two groups. Results evidenced the probability of the arrival of a new genetic population of nearly 40%, and it seems likely that the stranded fruits of external provenance did not come from the nearest P. oceanica meadows of Tuscany but were probably carried ashore by the Corsica current, as supported by an oceanographic analysis.     

Lactobacillus intestinalis (ex Hemme 1974) sp. nov., nom. rev., isolated from the intestines of mice and rats

The genetic and phenotypic properties of 10 strains identified as Lactobacillus intestinalis sp. nov. were examined. These strains constitute a distinct species which can be differentiated from all of the previously described homofermentative species in the genus Lactobacillus by their carbohydrate fermentation pattern. The guanine-plus-cytosine contents of their DNAs are 33 to 35 mol%. DNAs from 10 other Lactobacillus species did not exhibit significant levels of relatedness to representative strains of the new species. The name Lactobacillus intestinalis (ex Hemme) sp. nov., nom. rev. is proposed for these isolates, and strain Th4 (= ATCC 49335 = JCM 7548) is the type strain.     

Lactobacilli prevent hydroxy radical production and inhibit Escherichia coli and Enterococcus growth in system mimicking colon fermentation

Aims: To explore the effect of Lactobacillus on redox state of colon chyme. Methods and Results: Nine Lactobacillus strains were studied for the inhibition of lipid peroxide formation in Fe²⁺/ascorbate system and for their ability to chelate ‘free’ ferrous ion. The result shows both properties were strain specific and no relationship between them was found. Both properties of Lactobacillus paracasei Fn032, Lactobacillus rhamnosus GG (LGG) and Lactobacillus sp. Fn001 were successively decreasing. LGG and Fn032 significantly decreased hydroxyl radicals (P < 0·01) in colonic fermentation model, in which considerable hydroxyl radicals occurred spontaneously. Addition of ferrous ion induced the production of hydroxyl radicals, which could be significantly inhibited by LGG, Fn032 (P < 0·01) and Fn001 (P < 0·05). Ferrous ion significantly induced the growth of Enterococcus and Escherichia coli, which could be inhibited by all three Lactobacillus strains. Escherichia coli and Enterococcus show significantly positive correlation with hydroxyl radicals with R of 0·96 (P = 0·0002) and 0·91 (P = 0·0017), respectively. Conclusions: Antioxidative Lactobacillus could modulate redox state in colonic fermentation system, which is related to their free radical–scavenging ability or antibacterial effect. Significance and Impact of the Study: This study proves that Lactobacillus strain could influence the redox state of gut chyme. Evaluation of antioxidative ability might be a powerful method for screening probiotic Lactobacillus strains.     

Patterns of survival and volatile metabolites of selected <Emphasis Type="Italic">Lactobacillus</Emphasis> strains during long-term incubation in milk

The focus of this study was to monitor the survival of populations and the volatile compound profiles of selected Lactobacillus strains during long-term incubation in milk. The enumeration of cells was determined by both the Direct Epifluorescent Filter Technique using carboxyfluorescein diacetate (CFDA) staining and the plate method. Volatile compounds were analysed by the gas-chromatography technique. All strains exhibited good survival in cultured milks, but Lactobacillus crispatus L800 was the only strain with comparable growth and viability in milk, assessed by plate and epifluorescence methods. The significant differences in cell numbers between plate and microscopic counts were obtained for L. acidophilus strains. The investigated strains exhibited different metabolic profiles. Depending on the strain used, 3 to 8 compounds were produced. The strains produced significantly higher concentrations of acetic acid, compared to other volatiles. Lactobacillus strains differed from one another in number and contents of the volatile compounds.     

Cloning and analysis of bile salt hydrolase genes from Lactobacillus plantarum CGMCC No. 8198

Genes coding for bile salt hydrolase of Lactobacillus plantarum CGMCC 8198, a novel probiotic strain isolated from silage, were identified, analyzed and cloned. L. plantarum strongly resisted the inhibitory effects of bile salts and also decreased serum cholesterol levels by 20 % in mice with hypercholesterolemia. Using RT-PCR analysis, bsh2, bsh3 and bsh4 were upregulated by bile salts in a dose-dependent manner. All three bsh genes had high similarity with those of other Lactobacillus strains. All three recombinant BSHs had high activities for the hydrolysis of glycodeoxycholic acids and taurodeoxycholic acids.     

Phenotypic and genotypic analyses of lactic acid bacteria in local fermented food, breast milk and faeces of mothers and their babies

Lactic acid bacteria (LAB) are generally accepted as beneficial to the host and their presence is directly influenced by ingestion of fermented food or probiotics. While the intestinal lactic microbiota is well-described knowledge on its routes of inoculation and competitiveness towards selective pressure shaping the intestinal microbiota is limited. In this study, LAB were isolated from faecal samples of breast feeding mothers living in Syria, from faeces of their infants, from breast milk as well as from fermented food, typically consumed in Syria. A total of 700 isolates were characterized by genetic fingerprinting with random amplified polymorphic DNA (RAPD) and identified by comparative 16S rDNA sequencing and Matrix Assisted Laser Desorption Ionization-Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS) analyses. Thirty six different species of Lactobacillus, Enterococcus, Streptococcus, Weissella and Pediococcus were identified. RAPD and MALDI-TOF-MS patterns allowed comparison of the lactic microbiota on species and strain level. Whereas some species were unique for one source, Lactobacillus plantarum, Lactobacillus fermentum, Pediococcus pentosaceus and Lactobacillus brevis were found in all sources. Interestingly, identical RAPD genotypes of L. plantarum, L. fermentum, L. brevis, Enterococcus faecium, Enterococcus faecalis and P. pentosaceus were found in the faeces of mothers, her milk and in faeces of her babies. Diversity of RAPD types found in food versus human samples suggests the importance of host factors in colonization and individual host specificity, and support the hypothesis that there is a vertical transfer of intestinal LAB from the mother's gut to her milk and through the milk to the infant's gut.     

Assessment and comparison of probiotic potential of four Lactobacillus species isolated from feces samples of Iranian infants

The probiotic potential of Lactobacillus species isolated from infant feces was investigated. For this study, the antibiotic susceptibility, tolerance in gut‐related conditions, antimicrobial activity, and ability to adhere to a human colorectal adenocarcinoma cell line (Caco‐2 cells) of four common Lactobacillus species (Lactobacillus paracasei [n = 15], Lactobacillus rhamnosus [n = 45], Lactobacillus gasseri [n = 20] and Lactobacillus fermentum [n = 18]) were assessed. Most isolates that which were sensitive to imipenem, ampicillin, gentamycin, erythromycin and tetracycline were selected for other tests. L. gasseri isolates had the greatest sensitivity to gastric and intestinal fluids (<10% viability). L. fermentum (FH5, FH13 and FH18) had the highest adhesion to Caco‐2 cells. The lowest antibacterial activity against pathogenic bacteria was shown by L. gasseri strains in spot tests. Furthermore, non‐adjusted cell‐free culture supernatants with low pH had greater antimicrobial activity, which was related to organic acid. The results showed that some isolates of L. rhamnosus and L. fermentum are suitable for use as a probiotic.