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PubMed2001

An in vitro study of the pH-lowering potential of salivary lactobacilli associated with dental caries.

AIMS: Lactobacilli are known to produce acids from sucrose or glucose. This acid production can cause a drop in pH which is sufficiently significant to demineralize the hard tissues of the teeth. Some authors have demonstrated the benefits of substituting sorbitol or xylitol for sucrose. The aim of this work was to study the acid production of salivary lactobacilli with one test sugar (glucose) and two polyols (sorbitol and xylitol). METHODS AND RESULTS: The pH-lowering potential of three strains of oral lactobacilli was recorded with glucose or one of the polyols at three different concentrations. The results showed that polyols were broken down by certain strains of lactobacilli. When this degradation took place, the pH dropped to values sufficiently low to demineralize the hard tissues of the teeth. CONCLUSIONS: Further studies must be carried out on the metabolism of polyols before encouraging their widespread substitution for sucrose.

Child↗
PubMed2003

Protease, peptidase and esterase activities by lactobacilli and yeast isolates from Feta cheese brine.

AIMS: The study of peptidase, esterase and caseinolytic activity of Lactobacillus paracasei subsp. paracasei, Debaryomyces hansenii and Sacchromyces cerevisiae isolates from Feta cheese brine. METHODS AND RESULTS: Cell-free extracts from four strains of Lact. paracasei subsp. paracasei, four strains of D. hansenii and three strains of S. cerevisiae, isolated from Feta cheese brine were tested for their proteolytic and esterase enzyme activities. Lactobacillus paracasei subsp. paracasei strains had intracellular aminopeptidase, dipeptidyl aminopeptidase, dipeptidase, endopeptidase and carboxypeptidase activities. Esterases were detected in three of four strains of lactobacilli and their activities were smaller with higher molecular weight fatty acids. The strains of yeasts did not exhibit endopeptidase as well as dipeptidase activities except on Pro-Leu. Their intracellular proteolytic activity was higher than that of lactobacilli. Esterases from yeasts preferentially degraded short chain fatty acids. Lactobacilli degraded preferentially beta-casein. Caseinolytic activity of yeasts was higher than that of lactobacilli. CONCLUSIONS: The results suggest that Lact. paracasei subsp. paracasei and yeasts may contribute to the development of flavour in Feta cheese. SIGNIFICANCE AND IMPACT OF THE STUDY: Selected strains could be used as adjunct starters to make high quality Feta cheese.

Aminopeptidases↗
PubMed2002

Aggregation of animal lactobacilli with O157 enterohemorrhagic Escherichia coli.

The effect of selected autoaggregative lactobacilli on enterohemorragic O157 Escherichia coli was studied. A total of 27 Lactobacillus sp. strains were examined for expression of autoaggregation and cell surface hydrophobicity. Autoaggregative isolates were obtained from the crops of chickens and vaginas of calves. Aggregative activity was seen between eight autoaggregative lactobacilli and six strains of enterohemorrhagic E. coli O157. The presence of aggregation-promoting factor (apf gene) was confirmed by polymerase chain reaction (PCR). We propose that autoaggregative lactobacilli that aggregate with enterohemorrhagic E. coli can express a class of APF proteins that exhibit the function of an aggregative mediator. The results of this study suggest that APF-producing lactobacilli could represent a further mechanism in the interaction of comensal microflora with enterohemorrhagic E. coli.

Animals↗
PubMed2001

RAPD-PCR characterization of lactobacilli isolated from artisanal meat plants and traditional fermented sausages of Veneto region (Italy).

AIMS: The study was carried out to evaluate the use of randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) as a method for the identification of lactobacilli isolated from meat products. METHODS AND RESULTS: RAPD-PCR with primers M13 and D8635 was applied to the identification and intraspecific differentiation of 53 lactobacilli isolates originating from traditional fermented sausages and artisanal meat plants of the Veneto region (Italy). Most of the isolates were assigned to the species Lactobacillus sakei and Lact. curvatus; differentiation of groups of strains within the species was also possible. CONCLUSION: RAPD-PCR could be applied to the identification of lactobacilli species most commonly found in meat products. SIGNIFICANCE AND IMPACT OF THE STUDY: The method, which is easy and rapid to perform, could be useful for the study of the lactobacilli populations present in fermented sausages, and could help in the selection of candidate strains to use as starter cultures in meat fermentation.

Bacterial Typing Techniques↗
PubMed2001

Lactobacilli-mediated control of vaginal cancer through specific reactive oxygen species interaction.

Klebanoff et al. proposed that hydrogen peroxide-producing lactobacilli and peroxidase in the vagina of healthy women might be responsible for the prevention of vaginosis and also might exert an antitumor effect (1). Based on recent evidence on superoxide anion generation by transformed cells (2,3) and on the potential of myeloperoxidase for selective apoptosis induction in transformed cells (4), a model for specific reactive oxygen species interaction during lactobacilli-mediated tumor control in the vagina is presented here. We propose that peroxidase, which converts hydrogen peroxide into hypochlorous acid, is responsible for creating a microbicidal vaginal milieu by maintaining a balanced, non-toxic, steady state level of the microbicides H(2)O(2)and HOCI. In case individual superoxide anion-producing transformed cells eventually appear in the mucosa they will be driven into apoptosis by interaction of HOCI with superoxide anions which leads to the generation of hydroxyl radicals. Hence selective apoptosis induction in transformed cells represents the key element of lactobacilli-mediated antitumor defense. Since papilloma virus infected cells are resistant to this pathway of apoptosis induction, they are plausible candidates for circumvention of lactobacilli-mediated control of oncogenesis.

Apoptosis↗
PubMed2005

Effect of yogurt with Bifidobacterium DN-173 010 on salivary mutans streptococci and lactobacilli in young adults.

Probiotic bacteria are thought to reduce the risk of disease. Previous studies have suggested that lactobacilli-derived probiotics in dairy products may affect the oral ecology, but the effect of bifidobacteria has not previously been reported. The aim of the present study was to examine whether or not short-term consumption of yogurt containing bifidobacteria would affect the salivary levels of mutans streptococci and lactobacilli in young adults. A double-blind, randomized crossover study was performed and 21 healthy subjects were followed over four periods. During periods 2 and 4 (2 weeks each), they ingested 200 g yogurt containing Bifidobacterium DN-173 010 once daily or a control yogurt without viable bacteria. Periods 1 and 3 were run-in and washout periods, respectively. Salivary mutans streptococci and lactobacilli were enumerated with chair-side kits. A statistically significant reduction (p <0.05) of salivary mutans streptococci was recorded after the probiotic yogurt consumption, which was in contrast to the controls. A similar trend was seen for lactobacilli, but this decrease failed to reach statistical significance. In conclusion, probiotic bifidobacteria in yogurt may reduce the levels of selected caries-associated microorganisms in saliva.

Adult↗
PubMed2004

Immunomodulation by probiotic lactobacilli in layer- and meat-type chickens.

1. The aim of the experiments was to evaluate whether selected probiotic lactobacillus strains have different immunomodulating effects in layer- and meat-type strain chickens. 2. Humoral and cellular specific and non-specific immune responses were studied by experiments on cellular proliferation, entry and survival of Salmonella bacteria in gut and spleen leukocytes, immunoglobulin isotypes and specific immunoglobulin titres. 3. The effects of two different feeding regimes (short and continuous feeding) and doses for administration of lactobacilli were studied. 4. The lactobacillus strains that were evaluated showed modulating effects on the immune system of layer- and meat-type chickens. 5. In meat-type strain chickens the lactobacilli had a stimulating effect when the chickens were young (up to 3 weeks) and the dose was relatively high, whereas in layer-type chickens a lower effective dose and discontinuous administration was also effective. 6. Immunoprobiotic lactobacilli can have a positive effect on humoral and cellular immune responses in layer- and meat-type strain chickens, but the lactobacillus strain to be used, the age of the animals and effective dose of lactobacilli to be administered need to be optimised.

Animals↗
PubMed2001

Antibacterial susceptibility of intestinal lactobacilli of healthy children.

We investigated the antibacterial susceptibility of intestinal lactobacilli of Estonian and Swedish children aged 1-2 y. Sixty isolates (10 species) of lactobacilli (29 Estonian and 31 Swedish strains) were tested against ampicillin, cefuroxime, cefoxitin, gentamicin, ciprofloxacin, tetracycline, vancomycin, metronidazole and erythromycin. We observed that intestinal lactobacilli do not display uniform susceptibility to antibiotics. None of the tested lactobacilli was resistant to ampicillin, gentamicin and erythromycin. Single strains were resistant to cefuroxime and tetracycline, about half of the strains to cefoxitin and ciprofloxacin and 73% of the strains to vancomycin. All studied strains were resistant to metronidazole. Most of the strains investigated were resistant to two or three antibiotics out of nine. Some differences in susceptibility were noted between strains belonging to different fermentation types. No differences in susceptibility were found between Estonian and Swedish isolates. Metronidazole, cefoxitin, vancomycin and ciprofloxacin seem to be safer for gastrointestinal lactoflora than other tested antibiotics in both countries.

Anti-Bacterial Agents↗
PubMed2006

Probiotic lactobacilli and bacteraemia in Stockholm.

The objective of the present study was to determine the incidence of lactobacilli-induced bacteraemia in Stockholm, Sweden, between January 1998 and March 2004, and to identify the possible presence of probiotic strains. Isolated strains were checked for growth on selective lactobacilli-agar and the biochemical profiles were determined. The lactobacilli strains were further analysed with molecular methodologies to ascertain eventual similarities with the probiotic strains Lactobacillus paracasei subsp. paracasei F19 (LMG P 17806), Lactobacillus acidophilus NCFB 1748 and Lactobacillus rhamnosus GG (ATCC 53103). The minimum inhibitory concentrations of selected antimicrobial agents were determined by the agar dilution method. The incidence of bacteraemia cases caused by lactobacilli remained at the same level during the study period and constituted to <1% of the total number of bacteraemia cases each y. L. paracasei subsp. paracasei F19, L. acidophilus NCFB 1748 and L. rhamnosus GG were not identified in any of the samples.

Anti-Bacterial Agents↗
PubMed2005

Characterisation of potentially probiotic vaginal lactobacilli isolated from Argentinean women.

This study aims to evaluate potentially beneficial properties of 20 strains of vaginal lactobacilli isolated from women in Tucumán, Argentina, by determining acid and hydrogen peroxide production and auto-aggregation ability. The microorganisms were characterised genetically by amplified ribosomal 16S-DNA restriction analysis (ARDRA). Lactobacillus gasseri and L. rhamnosus were the predominant species identified among the 20 vaginal lactobacilli strains. Most achieved low pH values after 12 h incubation at 37 degrees C and produced hydrogen peroxide in static culture. However, pH decrease and semi-quantitative hydrogen peroxide production of most homofermentative lactobacilli were significantly higher than those of heterofermentative lactobacilli. Of the 20 strains studied, only three demonstrated remarkable auto-aggregation patterns. Four strains were selected for possible use in a probiotic product for vaginal application; however, further in vitro study of other potentially probiotic characteristics is required before attempting clinical trials.

DNA, Bacterial↗
PubMed2001

Factors associated with acquisition of, or persistent colonization by, vaginal lactobacilli: role of hydrogen peroxide production.

To identify factors that predict sustained colonization by vaginal lactobacilli, microbiologic, behavioral, and demographic data were obtained from 101 nonpregnant women at baseline and at 4 and 8 months. A total of 272 isolates of lactobacilli were identified to the species level by use of whole chromosomal DNA homology to type strains. The predominant lactobacilli were the species Lactobacillus crispatus (38%) and L. jensenii (41%). Of 57 women initially colonized by H(2)O(2)-producing L. crispatus or L. jensenii, 23 (40%) remained colonized over 8 months, compared with 1 (5%) of 21 women colonized by other H(2)O(2)-producing species or by H(2)O(2)-negative strains (P=.01). Frequency of sexual intercourse (> or =1 sex act per week) was associated with loss of colonization with H(2)O(2)-producing lactobacilli (P=.018), as was antibiotic use (P< or =.0001). Other behavioral and demographic characteristics did not predict sustained colonization. The production of H(2)O(2) is closely linked with species and is a predictor for sustained long-term colonization of the vagina.

Adolescent↗
PubMed1993

Lactobacilli and the normal human anaerobic microflora.

The normal human microflora is a complex and usually stable ecosystem. The intestinal microflora is important to the host with regard to many metabolic functions and in resistance to bacterial infections. Administration of antimicrobial agents may disrupt the normal microflora, leading to a decrease in colonization resistance and alterations in metabolic activities of the intestinal bacteria. Antimicrobial therapy may also be accompanied by gastrointestinal disturbances and a reduction or elimination of lactobacilli in the intestinal microflora. Lactobacilli are part of the normal gram-positive anaerobic microflora. Through the production of lactic and acetic acids, hydrogen peroxide, and antimicrobial substances, these microorganisms possibly contribute to the maintenance of colonization resistance. Several studies have indicated a protective effect of lactobacilli against potential pathogens in the gastrointestinal tract. In view of these beneficial properties, it is considered important to maintain or increase the levels of lactobacilli in the intestinal microflora.

Animals↗
PubMed1993

The normal vaginal flora, H2O2-producing lactobacilli, and bacterial vaginosis in pregnant women.

In this study of the vaginal flora of 171 pregnant women in labor at term, the flora was categorized as normal (Lactobacillus predominant), intermediate, or representative of bacterial vaginosis (BV) on the basis of a vaginal smear. BV was diagnosed in 39 women (23%); the vaginal flora was classified as normal in 50% of cases and as intermediate in 27%. H2O2-producing lactobacilli were recovered from 5% of women with BV, 37% of those with an intermediate flora, and 61% of those with a normal flora. H2O2-negative lactobacilli were equally frequent (57%-65%) in all three groups. The microorganisms most frequently recovered from women with BV included Gardnerella vaginalis, Prevotella bivia/disiens, Bacteroides ureolyticus, Prevotella corporis/Bacteroides levii, Fusobacterium nucleatum, Mobiluncus species, Peptostreptococcus prevotii, Peptostreptococcus tetradius, Peptostreptococcus anaerobius, viridans streptococci, Ureaplasma urealyticum, and Mycoplasma hominis (P < .05 for each). The presence of all but three of these organisms was inversely related to vaginal colonization by H2O2-producing lactobacilli; the exceptions were B. ureolyticus, F. nucleatum, and P. prevotii. Other microorganisms were equally frequent among women with and without BV. We conclude that specific groups of anaerobes are associated with BV in this population and that a strong association exists between species associated with BV and those inhibited by H2O2-producing lactobacilli.

Adolescent↗
PubMed1999

Dietary calcium phosphate stimulates intestinal lactobacilli and decreases the severity of a salmonella infection in rats.

We have shown recently that dietary calcium phosphate (CaPi) has a trophic effect on the intestinal microflora and strongly protects against salmonella infection. It was speculated that precipitation by CaPi of intestinal surfactants, such as bile acids and fatty acids, reduced the cytotoxicity of intestinal contents and favored growth of the microflora. Because lactobacilli may have antagonistic activity against pathogens, the main purpose of the present study was to examine whether this CaPi-induced protection coincides with a reinforcement of the endogenous lactobacilli. In vitro, Salmonella enteritidis appeared to be insensitive to bile acids and fatty acids, whereas Lactobacillus acidophilus was killed by physiologically relevant concentrations of these surfactants. Additionally, after adaptation to a purified diet differing only in CaPi concentration (20 and 180 mmol CaHPO4. 2H2O/kg), rats (n = 8) were orally infected with S. enteritidis. Besides reducing the cytotoxicity and the concentration of bile acids and fatty acids of ileal contents and fecal water, CaPi notably changed the composition of ileal bile acids in a less cell-damaging direction. Significantly greater numbers of ileal and fecal lactobacilli were detected in noninfected, CaPi-supplemented rats. As judged by the lower urinary NOx excretion, which is a biomarker of intestinal bacterial translocation, dietary CaPi reduced the invasion of salmonella. Additionally, the colonization resistance was improved considering the reduction of excreted fecal salmonella. In accordance, fewer viable salmonella were detected in ileal contents and on the ileal mucosa in the CaPi group. In conclusion, reducing the intestinal surfactant concentration by dietary CaPi strengthens the endogenous lactobacilli and increases the resistance to salmonella.

Animals↗
PubMed1998

Uncooked, lactobacilli-rich, vegan food and rheumatoid arthritis.

We tested the effects of an uncooked vegan diet, rich in lactobacilli, in rheumatoid patients randomized into diet and control groups. The intervention group experienced subjective relief of rheumatic symptoms during intervention. A return to an omnivorous diet aggravated symptoms. Half of the patients experienced adverse effects (nausea, diarrhoea) during the diet and stopped the experiment prematurely. Indicators of rheumatic disease activity did not differ statistically between groups. The positive subjective effect experienced by the patients was not discernible in the more objective measures of disease activity (Health Assessment Questionnaire, duration of morning stiffness, pain at rest and pain on movement). However, a composite index showed a higher number of patients with 3-5 improved disease activity measures in the intervention group. Stepwise regression analysis associated a decrease in the disease activity (measured as change in the Disease Activity Score, DAS) with lactobacilli-rich and chlorophyll-rich drinks, increase in fibre intake, and no need for gold, methotrexate or steroid medication (R2=0.48, P=0.02). The results showed that an uncooked vegan diet, rich in lactobacilli, decreased subjective symptoms of rheumatoid arthritis. Large amounts of living lactobacilli consumed daily may also have positive effects on objective measures of rheumatoid arthritis.

Adult↗
PubMed1994

Identification of lactobacilli from sourdough and description of Lactobacillus pontis sp. nov.

The microflora of sourdough preparations was investigated by examining the physiological characteristics, whole-cell protein patterns, and 16S rRNA sequences of Lactobacillus isolates. Strains isolated from sourdough were placed in the species Lactobacillus brevis, Lactobacillus sanfrancisco, and Lactobacillus reuteri. 16S rRNA sequences were determined for L. brevis, Lactobacillus fructivorans, Lactobacillus fermentum, L. sanfrancisco, and L. reuteri, and oligonucleotide probes for fast specific identification of these sourdough lactobacilli were deduced. The physiological characteristics, protein patterns, and 16S rRNA sequences of these organisms were compared with data for other sourdough lactobacilli and additional reference strains. Strains of a Lactobacillus species were isolated from rye sourdough; these strains may account for most of the flora in sourdough made from wheat or rye. These organisms were differentiated from other sourdough lactobacilli by their protein pattern, 16S rRNA sequence, G + C content, and physiological properties. The 16S rRNA sequence of this species was determined, and we constructed a phylogenetic tree which reflected the relationships of this species to other lactobacilli. This organism is closely related to L. reuteri. A new Lactobacillus species, Lactobacillus pontis, is proposed. The type strain is L. pontis LTH 2587 (= DSM 8475 = LMG 14187). We describe a general strategy in which a polyphasic approach was used to characterize a new species.

Bacterial Proteins↗
PubMed1988

Factors affecting growth and lipase production by meat lactobacilli strains and Brochothrix thermosphacta.

Lipolytic activity of lactobacilli strains and Brochothrix thermosphacta was cell-related; no significant activity was found in the supernatant fluids. Most lipase was produced during the logarithmic phase of growth and was greatly affected by growth conditions. The optimal temperatures for growth and lipase production were respectively 24 degrees C for B. thermosphacta and 30 degrees C for lactobacilli. For all strains, an initial pH of around 7.0 for the medium and low glucose concentration stimulated lipase production. Tributyrin inhibited both growth and lipase production at a concentration of 0.1% for B. thermosphacta or 1% for lactobacilli. Butyric acid (0.1%) and anaerobic culture inhibited lipase production by B. thermosphacta while these two factors had no effect on enzyme production by lactobacilli.

Animals↗
PubMed1991

Establishment in the piglet gut of lactobacilli capable of degrading mixed-linked beta-glucans.

The establishment in piglets of lactobacilli with ability to degrade mixed-linked (1----3), (1----4) beta-D-glucans was studied in faeces from 15 animals. The piglets had free access to creep feed with an estimated content of 2% beta-D-glucans from 5 days of age. On days 3 and 35, ca log 8 cfu/g of beta-glucan-degrading lactobacilli were found in a majority of the samples. On days 7, 14 and 21 such bacteria were only found occasionally. During establishment of the microflora in the neonate, the faecal lactobacilli of the piglet seemed related to those of the sow. Later, the metabolic activity of the lactobacilli in piglet faeces showed a connection to the composition of the diet. The possible relation of these bacteria to occurrence of beta-glucanases attributed to be endogenous in the pig is discussed.

Analysis of Variance↗