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PubMed1997

[Criteria for selection of lactobacilli for probiotic use].

The present knowledge of research makes it possible to use a whole range of stabilized micro-organisms and their metabolites for the production of preparations known as probiotics. The mechanism of the effect of probiotics, although it is not fully elucidated, is closely connected with the properties of the production strains. When selecting them, it is necessary to respect the origin of the strain used, its ability to adhere to the epithelial cells of the gut and to produce the inhibitory substances, the ability to survive and grow in the respective ecological units. The strain should be genetically stable, it should have good growth properties in vitro and in vivo, to maintain its high viability at processing, lyophilization and storage. Lactobacilli belong to the micro-organisms most frequently used to prepare the probiotics. The statement that lactobacilli inhibit the colonization of pathogenic bacteria upon the intestinal epithelium has been confirmed by many experiments on experimental germ-free and/or gnotobiotic animals. This inhibitory process known as "competitive exclusion" can be explained by the competition for the adherence sites on the intestinal mucosa between pathogens and lactobacilli and by the production of inhibitory substances. The host specificity as well as different degree of the expression of adherent phenotype, which is conditioned, in addition to the effect of the external environment also by the presence of plasmids of adherence, present the important property of the adherence of lactobacilli. The host specificity of the lactobacilli is closely connected with the presence of the specific molecules of receptors on the host cells which can be distinguished by means of specific molecules of the bacterial cells. The competition for the nutrients to be found on the intestinal epithelium, which present the growth substrates for both the probiotic strains and the pathogens, may present an important factor influencing the colonization of lactobacilli. The inhibitory components of the lactobacilli comprise the production of bacteriocins, toxic metabolites of the oxygen and organic acids. The inhibitory spectrum of the bacteriocins is different; the overwhelming majority of them inhibits G+ bacteria within the genus or taxonomically close to the genus of Lactobacillus, others such as bulgaricin, acidolin, laktocidin, acidophilin and non-protein substance reuterin are active against a wide spectrum of G+, G- bacteria, yeasts and fungi. Of toxic oxygen metabolites, the production of hydrogen peroxide is of importance. The hydrogen peroxide along with lactoperoxidase-thiocyanate milk system exerts bacteriocid effects on most pathogens. The production of organic acids (lactic, acetic) by lactobacilli is considered to be the primary regulator of the gut microbial activity in animals. The lactic acid as a product of the intestinal fermentation is further metabolized by lactate utilizing bacteria to VFA, thus the environment of the digestive tract is acidified and the acidosensitive pathogens cannot exert their effect. When pH of the environment falls, the concentration of molecular (non-dissociated) form of weak organic acids (acetic acid, VFA) elevates. The above acids diffuse through the cell membrane into a cell, thereby exhibiting higher inhibitory capacity. In case the mechanism of the effect of probiotics is fully elucidated, the criteria of the selection could be more precisely defined and thereby also the efficiency of probiotics would be improved.

Animals↗
PubMed1999

Comparison of media for the detection of bifidobacteria, lactobacilli and total anaerobes from faecal samples.

The interest in functional foods, probiotics and prebiotics requires a proper method to determine specific bacterial groups in the intestinal flora, especially bifidobacteria and lactobacilli. Three media for lactobacilli (MRS, Rogosa, LAMVAB), three media for bifidobacteria (RB, NPNL, Beerens medium) and nine media for total anaerobes have been tested for selectivity and recovery. For total anaerobes Faecal Reinforced Clostridial Agar (FRCA) showed the highest cfu/g, followed by Columbia Blood Agar and BHI Blood agar. There were no significant differences between the media tested. Reduced physiological salt solution was found to be the best dilution medium. For bifidobacteria and lactobacilli samples of human faeces, cat faeces and pig ileal contents were used. Bifidobacteria could reliably be determined on all three media tested in human faeces, but not on pig ileal contents or cat faeces. Absolute counts were highest in human samples. No lactobacilli could be isolated on MRS in either sample, none of the colonies in the countable plates were lactobacilli. For Rogosa over 90% of the colony types observed in human samples were not lactobacilli. For cat faeces this was 58%, but no false positives were observed in the pig ileal samples. For LAMVAB the percentages of false positive colony types were 9, 14 and 0% for human, cat and pig samples. It can be concluded that for bifidobacteria RB and Beerens medium show comparable results, and can be used to quantify bifidobacteria in human faeces, but none of the media tested is suitable for reliably counting bifidobacteria from pig and cat samples. For lactobacilli LAMVAB shows the highest sensitivity.

Animals↗
PubMed2001

Effect of lactobacilli on yeast growth, viability and batch and semi-continuous alcoholic fermentation of corn mash.

AIMS: The aim of this study was to evaluate interactions between Saccharomyces cerevisiae and selected strains of lactobacilli regarding cell viabilities, and production of organic acids and ethanol during fermentation. METHODS AND RESULTS: Corn mashes were inoculated with yeasts and selected strains of lactobacilli, and fermented in batch or semi-continuous (cascade) mode. Ethanolic fermentation rates and viabilities of yeast were not affected by lactobacilli unless the mash was pre-cultured with lactobacilli. Then, yeast growth was inhibited and the production of ethanol was reduced by as much as 22%. CONCLUSION: Yeasts inhibited the multiplication of lactobacilli and this resulted in reduced production of acetic and lactic acids. The self-regulating nature of the cascade system allowed the yeast to recover, even when the lactobacilli had a head start, and reduced the size of the population of the contaminating Lactobacillus to a level which had an insignificant effect on fermentation rate or ethanol yield. SIGNIFICANCE AND IMPACT OF THE STUDY: Contamination during fermentation is normally taken care of by the large yeast inoculum, although yeast growth and fermentation rates could be adversely affected by the presence of high numbers of lactobacilli in incoming mash or in transfer lines.

Acetates↗
PubMed1992

Lactobacilli, anticarcinogenic activities and human intestinal microflora.

Lactobacilli belong to the normal oropharyngeal and intestinal microflora in humans. These microorganisms contribute to the stabilization of the microflora and maintain the colonization resistance against pathogens. Lactobacilli have been used as dietary supplements in order to prevent gastrointestinal disturbances. Claims have been made that certain strains of lactobacilli possibly exert anticarcinogenic activities. The activity of bacterial enzymes, implicated in colon carcinogenesis may be elevated by a high meat, Western-type diet. Supplements of Lactobacillus acidophilus decreased these levels in both rats and humans. Colon cancer patients given L. acidophilus fermented milk showed a significant increase both in numbers of intestinal lactobacilli and dietary calcium intake, while decreasing trends in levels of both soluble faecal bile acids and faecal bacterial enzymes, two risk makers for colon cancer, were observed. In vitro studies have revealed that lactobacilli and other lactic acid bacteria have the ability to absorb cooked food mutagens. Recent studies in humans have shown that intake of L. acidophilus significantly reduced the mutagen excretion after consumption of fried meat. Several mechanisms by which lactobacilli might exert anticarcinogenic effects are discussed. Thus, certain strains of lactobacilli might lower the colon cancer risk in humans.

Bacterial Physiological Phenomena↗
PubMed2006

Glutamate dehydrogenase activity in lactobacilli and the use of glutamate dehydrogenase-producing adjunct Lactobacillus spp. cultures in the manufacture of cheddar cheese.

AIMS: The study was undertaken to investigate the occurrence of glutamate dehydrogenase activity in different species of lactobacilli, and to determine, in a series of cheese-making trials, the effects of glutamate dehydrogenase-producing adjunct cultures on sensory attribute development during the maturation of cheddar cheese. METHODS AND RESULTS: The presence of dehydrogenase activity with glutamate as substrate was monitored in cell lysates of >100 strains from 30 different species of lactobacilli using a qualitative colorimetric plate screening assay. Activity was detectable in 25 of the 29 representative species obtained from culture collections and in 12 of the 13 non-starter species isolated from cheese. There were pronounced interspecies and strain differences in the occurrence, level and pyridine nucleotide specificity of the glutamate dehydrogenase activity detected. Among the non-starter lactobacilli the highest frequency of enzyme occurrence and activity was detected in the Lactobacillus plantarum isolates. The establishment of glutamate dehydrogenase-producing adjunct strains in the predominant population of lactobacilli in the cheese curd affected the formation of a number of volatile compounds in ripening cheddar cheese, while the presence of Lact. plantarum strains, in particular, was associated with an intensification and acceleration of aroma and flavour development during the maturation period. CONCLUSIONS: Glutamate dehydrogenase formation by lactobacilli is a strain-dependent metabolic attribute, and adjunct cultures expressing the activity that are able to proliferate during cheese ripening have a positive impact on the rate of development and the intensity of cheddar cheese aroma and flavour development. SIGNIFICANCE AND IMPACT OF THE STUDY: It has been demonstrated that some strains of glutamate dehydrogenase-producing lactobacilli have potential use as adjunct cultures to accelerate and intensify aroma and flavour formation during the manufacture of cheddar and, by analogy, other similar varieties of cheese. The importance of phenotypic discriminative monitoring of the dominant lactobacilli present during ripening to confirm adjunct establishment and population complexity was highlighted as was the requirement to establish the metabolic attributes of the non-starter population in uninoculated control cheeses in comparative trials.

Cheese↗
PubMed1982

Streptococcus mutans, lactobacilli and dental health in 13-14-year-old Swedish children.

The dental health and the prevalence of Streptococcus mutans and lactobacilli were examined in 101 13-114-year-old children. The average number of decayed (incipient caries) and filled surfaces (DFS) was 10.1 and 12.8, respectively. S. mutans was not detected in 11% of the children while 21% had 10(6) or more S. mutans per ml saliva. Lactobacilli were not found in 21% of the children whereas 11% had 10(5) or more lactobacilli per ml saliva. Statistically significant correlations were found between S. mutans and lactobacilli, S. mutans and DFS, lactobacilli and DFS and S. mutans plus lactobacilli and DFS. Increasing numbers of S. mutans and lactobacilli, alone and in combination, were associated with an increased caries frequency.

Adolescent↗
PubMed1989

Lactobacilli and bile salt hydrolase in the murine intestinal tract.

Mice that have a complex intestinal microflora but that do not harbor lactobacilli were used to determine the contribution of lactobacilli to the total bile salt hydrolase activity in the murine intestinal tract. Bile salt hydrolase activity in the ileal contents of these mice was reduced 86% in the absence of lactobacilli and by greater than 98% in the absence of lactobacilli and enterococci compared with samples from conventional mice. Bile salt hydrolase activities were lower in ileal and cecal contents from lactobacillus-free mice colonized with enterococci than in samples from lactobacillus-free mice colonized with lactobacilli. Bile salt hydrolase activity in the duodena, jejuna, ilea, and ceca of reconstituted lactobacillus-free mice colonized by lactobacilli was similar to that in samples from the intestinal tracts of conventional mice. We conclude from these studies that lactobacilli are the main contributors to total bile salt hydrolase activity in the murine intestinal tract.

Amidohydrolases↗
PubMed2004

Identification and H(2)O(2) production of vaginal lactobacilli from pregnant women at high risk of preterm birth and relation with outcome.

Lactobacilli, principally the strains that are hydrogen peroxide (H(2)O(2)) producing, may have a protective effect against vaginal colonization by pathogenic species such as those that cause bacterial vaginosis. Previous reports have also suggested that H(2)O(2)-producing lactobacilli in the vagina may protect pregnant women against ascending infection of the chorioamniotic membranes and uterine cavity. We report the identification and H(2)O(2) production of lactobacilli isolated from vaginal swabs collected at 20 weeks' gestation from a population of pregnant women at high risk of preterm birth. We also report the correlation between identification and H(2)O(2) production in relation to the outcomes of chorioamnionitis and preterm birth. Lactobacilli were identified by partial 16S rRNA gene sequencing. H(2)O(2) production by isolates was determined by a semiquantitative method. The most commonly isolated species were L. crispatus, L. gasseri, L. vaginalis and L. jensenii. Amounts of H(2)O(2) produced by lactobacilli varied widely. The presence of lactobacilli producing high levels of H(2)O(2) in the vagina of this population of pregnant women was associated with a reduced risk of bacterial vaginosis at 20 weeks' gestation and subsequent chorioamnionitis. L. jensenii and L. vaginalis produced the highest levels of H(2)O(2). We postulate that H(2)O(2)-producing lactobacilli are able to reduce the incidence of ascending infections of the uterus and the subsequent production of proinflammatory molecules which are important in the pathogenesis of chorioamnionitis and preterm birth.

Female↗
PubMed2004

Probiotic treatment increases salivary counts of lactobacilli: a double-blind, randomized, controlled study.

BACKGROUND/AIMS: Lactobacilli are used in the prevention and treatment of several diseases, but they are also known to play a role in the pathogenesis of dental caries. The aim of our study was to evaluate whether the oral administration of lactobacilli could change the salivary counts of these bacteria compared with placebo. Moreover, lactobacilli were administered in liquid and in capsule form to determine the role of direct contact with the oral cavity. METHODS: Thirty-five healthy volunteers were randomized into three groups to receive lactobacilli and/or placebo for 45 days: group A (n = 14) received probiotics in capsules and placebo in liquid form; group B (n = 16) took liquid probiotics and placebo in capsules, and group C (n = 5) used placebo in both liquid and capsule form. Streptococcus mutans populations served as control. The salivary counts of lactobacilli and S. mutans were measured semi-quantitatively using the CRT bacteria kit. RESULTS: Compared with placebo, the oral administration of probiotics, both in capsules and in liquid form, significantly increases salivary counts of lactobacilli (p = 0.005 and p = 0.02, respectively). S. mutans populations were not significantly modified. CONCLUSIONS: The increased salivary counts of lactobacilli may indicate the need to closely monitor the dental health of patients undergoing long-term probiotics treatment, even when this treatment is administrated in a form that avoids direct contact with the oral cavity.

Administration, Oral↗
PubMed1996

Prevalence of Streptococcus mutans and lactobacilli in 18-month-old children with cleft lip and/or palate.

The prevalence of Streptococcus mutans and lactobacilli was determined in 62 18-month-old Dutch children with a cleft lip and/or palate. Plaque and saliva samples were collected, a dental examination was performed, and the parents were interviewed with a structured questionnaire regarding general health, dietary habits, fluoride exposure, and socioeconomic class. Appropriate dilutions of the plaque and saliva samples were cultured on selective media to count all viable bacteria, S. mutans and lactobacilli. S. mutans was detected in the saliva of 45% of the children, and lactobacilli was detected in 16%. Also, S. mutans was detected in 48% of the plaque samples and lactobacilli in 8%. Of all of the variables examined, consumption of more than three snacks and beverages between main meals was significantly associated with presence of S. mutans in saliva. Preoperative infant orthopedic treatment (i.e., wearing an acrylic plate from shortly after birth) was significantly associated with presence of lactobacilli in saliva. The presence of S. mutans in the plaque samples was also significantly associated with presence of lactobacilli in saliva. These results indicate that children with oral cleft are at an increased risk of being infected by S. mutans and lactobacilli at a very early age. Such early colonization indicates a high risk for caries in the primary dentition.

Analysis of Variance↗
PubMed2000

Reduction of Campylobacter jejuni in a simulated chicken digestive tract by Lactobacilli cultures.

Studies were conducted to investigate the impact of a selected lactobacilli mixed culture on Campylobacter jejuni in simulated chicken digestive tract models. Veronal buffer solutions corresponding to the pH of successive segments of the chicken digestive tract were prepared. The lactobacilli mixtures were prepared by mixing four fresh lactobacilli cultures, including Lactobacillus acidophilus, Lactobacillus fermenentum, Lactobacillus crispatus, and Lactobacillus brevis. The C. jejuni and lactobacilli mixture were mixed with sterile poultry feed, and the previously prepared veronal buffer solutions were then added separately. The mixture was incubated at 41.1 degrees C for various lengths of time with periodic agitation. The feed passage time for five segments of the digestive tract were adopted: crop (pH 4.5), 30 min; proventriculus (pH 4.4), 15 min; gizzard (pH 2.6), 90 min; small intestine (pH 6.2), 90 min; and large intestine (pH 6.3), 15 min. The Campylobacter and lactobacilli were enumerated. An antagonistic effect on C. jejuni by the tested lactobacilli spp. was found in individual sections and the complete simulated digestive tract models. In the simulated complete chicken digestion system, no C. jejuni were found during the final incubation period when a lactobacilli mixture was present. The results of this in vitro study indicate the potential value of future in vivo studies.

Animals↗
PubMed1992

A comparison between commercial kits and conventional methods for enumeration of salivary mutans streptococci and lactobacilli.

Mutans streptococci (ms) and lactobacilli levels were determined by conventional and commercial dip-slide methods in three groups of young subjects, aged 5-6 years (93 subjects), 12-13 years (78 subjects) and 18-20 years (81 subjects). Using the same paraffin-stimulated saliva samples, ms and lactobacilli were estimated by conventional viable counts on modified mitis-salivarius agar (MSB) and Rogosa agar plates, and by inoculation of Dentocult SM and Dentocult LB dip-slides (Orion Diagnostica, Finland). The salivary ms and lactobacilli counts obtained from conventional agar plates were significantly correlated (P < 0.0001) with the dip-slide estimates of these organisms (Kendal Tau = 0.56, 0.71 respectively). Subjects in Group 2 showed the highest proportion (77 per cent) of individuals with salivary ms levels above 2.5 x 10(5) cfu/ml saliva; 99 per cent of that group had detectable levels of lactobacilli. Significantly different median salivary ms and lactobacilli levels were demonstrated between all groups except for lactobacilli levels between Groups 2 and 3. These dip-slide tests provided suitable and simple methods for screening salivary lactobacilli and ms levels which may have a useful role in the assessment of caries risk.

Adolescent↗
PubMed1993

Oral lactobacilli isolated from teenage orthodontic patients.

Orthodontic bands form retention areas which create favourable conditions for growth of lactobacilli. This study deals with the numbers and specific species of lactobacilli in the oral cavity of teenage orthodontic patients. High numbers of lactobacilli were obtained (log 6.398 +/- 0.761 cfu/ml) and the buffer capacity of saliva indicated a high caries risk amongst these individuals but the actual DMFT values were relatively low. Homofermentative lactobacilli predominated in both plaque and saliva and particularly L. salivarius and L. casei. These two lactobacilli species indicated that these patients are at a high caries risk. Several other homofermentative and heterofermentative lactobacilli were isolated which indicated the complexity of the oral lactobacilli community in saliva and plaque.

Adolescent↗
PubMed1981

Effects of lactobacilli on parameters of non-specific resistance of mice.

The viability of Lactobacillus plantarum in vivo and the effects of viable and heat-killed lactobacilli on parameters of non-specific resistance were studied. After intravenous administration of 10(8) viable lactobacilli, which is a dose with optimal adjuvant activity, viable lactobacilli could be isolated from spleens for more than 1 week and from livers and lungs for more than 3 weeks. Both viable and heat-killed lactabacilli stimulated the clearance of colloidal carbon, viable bacteria stimulated initially to a higher extent. Doses of 10(8) viable and heat-killed lactobacilli, but not less, stimulated non-specific resistance to Listeria monocytogenes and caused splenomegaly. Doses as small as 10(5) viable and heat-killed lactobacilli induced substantial natural killer (NK) cell activity in the peritoneal exudate 4 days after i.p. administration. Higher doses generally caused a dose-dependent increase of NK cell activity. Viable lactobacilli injected in the paw and to a lesser extent heat-killed bacteria caused a proliferative response in the draining popliteal lymph node, which peaked at day 5. Results are discussed in relation to adjuvanticity and comparisons are made with bacterial agents already used in immunotherapy.

Adjuvants, Immunologic↗
PubMed2004

Lactobacilli and enterococci--potential probiotics for dogs.

Forty strains of enterococci and forty strains of lactobacilli isolated from feces of 10 healthy dogs were tested for the antimicrobial activity, tolerance to bile and adhesion activity. The total count of fecal enterococci reached 5.5 log CFU/g and of lactobacilli 7.6 log CFU/g. Screening for production of bacteriocin-like substances showed an to partly inhibit the growth of Enterobacter sp. (hazy zones of inhibition). Ten strains of Enterococcus sp. and nine strains of Lactobacillus sp. were found without any inhibitory activity against all indicators used. Seven enterococcal strains and six lactobacilli with the broadest antimicrobial spectrum were selected for further probiotic assays. In the presence of 1% bile, the survival rate of selected enterococci (71.7-97.5%) was higher than that of lactobacilli (66.7-75.4%). The adhesion of strains to human intestinal mucus (5.1-8.2% by enterococci, 2.7-8.3% by lactobacilli) was found to be similar as adhesion to canine intestinal mucus (3.7-10.6% by enterococci, 2.1-6.0% by lactobacilli). Strain AD1, one lactobacillus isolate, reduced the higher level of serum cholesterol and alanine aminotransferase after oral administration to dogs suffering from diseases of the gastrointestinal tract.

Alanine Transaminase↗
PubMed2006

Mutans streptococci and lactobacilli in plaque on a leucite-reinforced dental ceramic and on a calcium aluminate cement.

In this in vivo study, the proportions of mutans streptococci and lactobacilli in plaque were examined (1) on proximal surfaces of bonded, leucite-reinforced ceramic crowns and (2) on class V restorations of calcium aluminate cement (CAC). The examined proportions were intraindividually compared with those of resin composite and enamel. Mutans streptococci and lactobacilli in samples from plaque that was accumulated for 10 days on the following surfaces were determined by cultivation on blood agar plates and species-selective plates: (1) proximal leucite-reinforced ceramic crown, class II composite and enamel (n=11); and (2) class V restoration of CAC and composite, and enamel (n=17). Mutans streptococci and lactobacilli in the samples were distributed in three groups: 0, >0-1, and >1% of total bacteria. The surfaces with detected mutans streptococci were similarly distributed between the materials and enamel. The highest proportion of mutans streptococci and lactobacilli were observed on ceramic followed by composite and enamel. A higher proportion of lactobacilli, but not of mutans streptococci, was detected on enamel compared to CAC and composite. However, no significant differences were found between the surfaces. Conclusively, the materials investigated did not show different relative proportions of mutans streptococci and lactobacilli in plaque, compared to enamel.

Adult↗
PubMed2005

Reduced quantity and hydrogen-peroxide production of vaginal lactobacilli in HIV positive women.

It has been suggested that vaginal lactobacilli may influence heterosexual transmission of HIV infection. The aim of this study was to compare the vaginal flora on Gram's stained and isolation rate, quantity and H2O2 production of lactobacilli between HIV positive and HIV negative women. Although, the prevalence of abnormal vaginal flora was increased in HIV infected women, there was no significant difference in isolation rate of vaginal lactobacilli between the two groups (71.87 vs. 83.33%; P>0.05). However, the results of this study showed significantly reduced quantity of lactobacilli in HIV infected women (P<0.01). In particular, the prevalence of H2O2-producing lactobacilli was lower in HIV positive as compared to HIV negative women (80 vs. 56.52%), with borderline significance (P=0.057). Taken together, our findings showed altered vaginal microflora with reduced quantity and hydrogen-peroxide production of vaginal lactobacilli in HIV positive women, but further studies are needed to assess its actual significance and potential benefit from the use of probiotic therapy.

Adult↗
PubMed2005

Presence of lactobacilli in the intestinal content of freshwater fish from a river and from a farm with a recirculation system.

Lactobacilli are Gram-positive and catalase negative rods commonly found in lactic acid fermented foods and in the gastrointestinal tract of mammals and birds. Few studies have described lactobacilli in freshwater fish. We analysed the presence of lactobacilli in the intestines of young and adult freshwater fish inhabiting a river environment and from fish reared in an aquaculture unit with a water recirculation system. Various species of lactobacilli were present in relatively high number in the intestines of edible fresh water fish from the river, especially in the warm season but in low numbers in the cold season. Lactobacilli were scarcely found in the intestines of edible farmed fish reared in a recirculation system in warm water. Lactobacilli are reported for the first time from the intestines of wild European eel, perch, rudd, ruffe, bleak, silver bream, chub, somnul and farmed African catfish. The two first fishes, and the last one are highly valuable species for fisheries and aquaculture. Additionally, improved methods for storage and bacteriological analysis of fish intestinal content are described. The natural presence of lactic acid bacteria in fish may be of great interest in producing fermented fish products worldwide.

Animals↗