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[Intestinal mucosa of gnotobiotic rats administered lactobacilli].

When lactobacilli are administered to gnotobiotic rats (Fischer strain), a gradual increase of lymphocytic, eosinophilic and mast cell infiltration of the intestinal connective tissue stroma, dilatation of vessels and their filling with lymphocytes is observed. Radioautographically 7 months later, migration and differentiation of enterocytes in the crypta--villus system of the iliac mucous tunic increases. In the mesenteric lymph nodes the postcapillary venules increase in number, lymphocytes migrate out of them, focal plasmocytic reaction with presence of some blastic forms takes place. Specific antibodies for lactobacilli in the blood serum either are absent or occur in low titers (1:2-1:8). Owing to the data obtained, a conclusion can be made on a weak immunogenecity of the lactobacilli. Their administration to the germ-free rats produces a certain cellular reaction, probably T-dependent, though any definite signs of hormonal response are absent. One--14 days after lactobacilli have been injected, in the rat intestine mucous tunic no microorganisms are revealed to fix to enterocytes. In cytoplasm of the absorbtive cell villi, the Golgi complex is subjected to hyperplasia and occupies an essential area over the nucleus. Within its cysterns, as well as in the mitochondrial and nuclear membrane areas, myelin-like bodies are revealed; evidently, they demonstrate certain changes in peroxidic oxidation of lipids..

Animals↗

[Ability of lactobacilli in the human microflora to produce lysozyme].

Lysozyme activity of 403 strains of lactobacilli were investigated; of these 26 were from foreign sets and 377 were isolated from the contents of the stomach, feces and vaginal discharge of healthy adults. The species reference of lactobacillae was confirmed by the results of study of their physiologo-biochemical properties with the aid of 45 tests. A method of agar plates was adapted to determination of lysozyme: the autoclaved suspension of Micrococcus lysodeikticus (strain No. 2665) was added to the agar medium MPC-I, and lactobacilli were cultivated for 4 days in the CO2 atmosphere at 37 degrees C. There was revealed the capacity of L. fermenti and L. brevis to produce lysozyme; in L. fermenti the lysozyme activity was much more frequent (p less than 0.001); strains of the rest of the species of lactobacilli differentiated by the Rogosa and Sharpe's classification proved to be lysozyme-negative. It was shown that the lactobacilli of the L. fermenti species, included into the microflora of the intestine and the vagina of healthy adults as a rule possessed lysozyme activity. L. fermenti strain 90T-S4 used in the production of dry lactobacterin also produced lysozyme. All this favours an important role of L. fermenti in the protective function of the microflora.

Adult↗

Therapy of bacterial vaginosis using exogenously-applied Lactobacilli acidophili and a low dose of estriol: a placebo-controlled multicentric clinical trial.

The efficacy of vaginal tablets (Gynoflor) containing 50 mg of a lyophilisate of viable, H2O2-producing Lactobacillus acidophilus (at least 10(7) colony forming units/tablet) and 0.03 mg estriol (CAS 50-27-1) for the treatment of bacterial vaginosis (BV) was tested in a multicentric, randomised, placebo-controlled clinical trial with parallel-group design. 32 non-menopausal women with positive diagnoses for BV, including intermediate cases, participated in the trial. Patients were diagnosed using the classical clinical parameters of BV according to Amsel and using microscopic analysis of the Gram-stained vaginal smear. A positive clinical diagnosis of BV required at least 2 of the following 4 clinical criteria to be positive; greyish-white, homogeneous leukorrhea; vaginal pH > 4.5; KOH test for volatile amines; presence of clue cells. Microscopic diagnosis of BV, on the other hand, was obtained if examination of the Gram-stained vaginal smear showed less than 6 lactobacilli per field of view (1000 x magnification). This corresponds to another definition of BV as "lactobacilli deficiency syndrome". The efficacy of the 6-day therapy with 1-2 vaginal tablets daily was evaluated using both clinical and microscopic analysis. Using Amsel's classical clinical parameters of BV, the cure rate (defined as < or = 1 of the 4 clinical criteria positive) two weeks after the start of therapy was 77% in the verum group and 25% in the placebo group. Four weeks after the start of therapy, the cure rate was 88% in the verum group and 22% in the placebo group. At both control examinations, the cure rate for the test group was significantly higher than that for the placebo group (p < 0.05, Fisher's exact test, 2-sided, significance level 0.05). In addition, the trial showed that after 6 days of treatment with the test preparation, the lactobacilli were capable of recolonising the vagina. A significant increase in the number of lactobacilli was observed in the Gram-stained vaginal smear for the patient group treated with the test preparation compared to the placebo patient group (p < 0.05, Fisher's exact test, 2-sided, significance level 0.05), two and four weeks after the start of the 6-day treatment.

Adult↗

The microbial flora of Awshari cheese with special reference to Lactobacilli.

Thirty-seven samples of Awshari cheese and 13 of Biza were examined microbiologically. Penicillia occurred in 2 samples of cheese and yeasts in 21, 3 of which contained Saccharomyces lactis. In 8 samples studied for the constitutive microflora, lactobacilli and streptococci were the most prevalent, with L. casei being the only Lactobacillus species isolated. Penicillia and yeasts occurred in all the samples of Biza, with Saccharomyces lactis being encountered in 5 out of 6 samples examined for the type of yeasts. The microbial flora consisted primarily of lactobacilli. Out of 98 lactobacilli isolated from 10 samples 55 were identified as betabacteria: 41 were attached to L. brevis, 13 L. buchneri and 1 L. pasteurianus. The remaining 43 isolates were streptobacteria: 21 belonged to L. coryniformis, 5 L. casei ssp pseudoplantarum, 3 ssp casei and 1 ssp alactosus, 2 L. plantarum ssp plantarum and 1 ssp arabinosus, 1 L. xylosus, 5 motile streptobacteria and 4 unidentifiable.

Cheese↗

Prophylactic co-trimoxazole and lactobacilli preparation in neutropenic patients.

A randomized study of intestinal decontamination was undertaken in 68 children with leukemia and solid tumours. Framycetin, colymycin, nystatin, and metronidazole were given in 35 neutropenic episodes in 33 children, while co-trimoxazole and lactobacilli preparation were administered in 35 episodes in 35 children. The diseases, severity of neutropenia, and incidence of infection at entry into study were comparable in the two groups. There was no significant difference in the incidence of infections developing during the phase of neutropenia. The median and range of time required to recover from neutropenia were also not different. Co-trimoxazole and lactobacilli were significantly better tolerated, there being no nausea and vomiting, no refusal to take medication, no dose reduction or change to an alternative regimen. We conclude that co-trimoxazole and lactobacilli preparation improve quality of life during a neutropenic episode and have the additional advantage of being relatively inexpensive.

Agranulocytosis↗

Regulation of acetic acid production by homo- and heterofermentative lactobacilli in whole-wheat sour-doughs.

The efficiency of sour-dough as a possible preservative agent of microbial spoilage of bread depends on its acetic acid content. As a secondary metabolite of sugar fermentation by lactic acid bacteria, acetic acid may be promoted in the presence of O2 or H+ acceptors. This paper studies the influence of O2 and high fructose content products (pure sugar, invert sugar, fructose syrup) addition on acetic acid production by hetero- (Lactobacillus brevis 25a, B-21, L-62; L. sanfrancisco L-99) and homofermentative (L. plantarum B-39) lactobacilli in whole-wheat sour-doughs [280 and 250 dough yield (DY)]. The pH and total titratable acidity (TTA) of sour-doughs after 44 h fermentation varied with DY and strain. As expected, the addition of O2 promoted greater increases in TTA with heterofermentative lactobacilli (15-42%) than with L. plantarum (15%). Fructose addition was only effective for heterofermentative strains, but the overall effects were smaller than those observed for oxygenation. The ability of lactobacilli to produce acetic acid in sour-doughs without treatment varied from 0.16 g/100 g flour at 44 h (B-39, 280, 350 DY) to 0.47-0.65% (L-62, 280, 350 DY). The production of acetic acid was positively promoted by all treatments. Oxygenation was again the most effective way of inducing acetic acid production; increases ranged from 54% (B-21) to 269% (L-99, 350 DY). The addition of H+ acceptors had variable effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗

Influence of lactobacilli on the adhesion of Staphylococcus aureus and Candida albicans to fibers and epithelial cells.

The ability of organisms to adhere to and form biofilms on fibrous materials is believed to be an important initiating step in the induction of several diseases, such as toxic shock syndrome. Using an in vitro assay, a moderately hydrophobic strain of Staphylococcus aureus (water contact angle 35 degrees) and a hydrophilic Candida albicans (shown by a hexadecane test) were highly adherent to commercial diaper fibers. The lumen side of the diaper was porous and the fibers were very hydrophobic (> 140 degrees), but the internal section was very hydrophilic (0 degrees), presumably for lus strains was present. Surfaces precoated with lactobacilli inhibited staphylococcal adhesion by 26-97%, and candida by 0-67%. When the lactobacilli were used to challenge adherent pathogens, there was 99% displacement of the S. aureus and up to 91% displacement of C. albicans. Hydrophobic L. acidophilus 76 (54 degrees) and T-13 (80 degrees) were the most effective of five Lactobacillus isolates tested at interference by precoating. The moderately hydrophilic L. casei var rhamnosus GR-1 (33 degrees) was the most effective at displacing the yeast. Experiments with uroepithelial cells also showed that the lactobacilli could significantly interfere with the adhesion of both pathogens to the cells. The results demonstrate the rapidity with which two pathogens adhered to fibers and epithelial cells, and raised the possibility that members of the normal female urogenital flora might interfere with infections caused by these organisms.

Adult↗

Binding of extracellular matrix proteins by lactobacilli.

Ten gut and ten vaginal Lactobacillus strains were investigated for their ability to bind type I collagen (Cn-I) and four selected gut lactobacilli were investigated for their binding to other extracellular matrix (ECM) molecules. Immobilized Cn-I (100 mg/L) in wells of microtitre plates was bound by all 10 autoaggregating vaginal strains and by 3 strains of gut lactobacilli from piglets in the range of A570 readings 0.114-1.806. L. acidophilus strain SV31 was much more adherent than the rest of strains. All four gut lactobacilli tested for binding to other ECM molecules displayed good binding to porcine fibronectin and heparin and some of them bound weakly to fetuin and porcine mucin. No binding of these strains was observed to bovine mucin, bovine fibrinogen and bovine lactoferrin.

Animals↗

Effect of lactobacilli on E. coli adhesion to Caco-2 cells in vitro.

Inhibitory effect of various lactobacilli against pathogenic strains of E. coli in model system Caco2 cells was determined by enumerating the number of adhering E. coli after pre-incubation (exclusion), post-incubation (displacement) or co-incubation (competition) with lactobacilli. Porcine E. coli strain F107 (F18ab, Stx2v) in the competition assay with porcine lactobacillus strain P10 gave bacterial counts 7.25 (log CFU per well); in the exclusion test it was only 7.05 while in displacement test it reached 7.29. The lowest E. coli counts adhering to Caco-2 cells were in exclusion assay (pre-incubation, Lactobacillus inoculated as the first). Pre-treatment of E. coli with our lactobacilli strains reduced the cultivable E. coli numbers.

Animals↗

Efficient protoplast regeneration for some homofermentative lactobacilli and pediococci.

Conditions for protoplast regeneration were examined for several strains of homofermentative lactobacilli and pediococci isolated from silage. Attempts to regenerate protoplasts using previously published agar regeneration media for lactobacilli were unsuccessful for most of the strains. Replacing or increasing colloidal substances in a medium containing raffinose and MgCl(2) as osmotic stabilizers enabled efficient regeneration of the protoplasts at a frequency of 10-99%. A medium containing gelatin, polyvinylpyrrolidone (PVP) and no agar was effective for Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus rhamnosus protoplasts. An agar medium containing PVP (PVP medium) was effective for Pediococcus sp. protoplasts, and addition of agarose to the PVP medium enabled regeneration of Lactobacillus casei protoplasts. A medium containing calcium alginate gel and no agar was effective for Lactobacillus curvatus protoplasts. The type of colloidal substance required for protoplast regeneration varied from species to species. This result suggested that several kinds of media may be necessary to regenerate protoplasts for all the genera of lactobacilli and pediococci.

Bacteriological Techniques↗

Headspace flavour compounds produced by yeasts and lactobacilli during fermentation of preferments and bread doughs.

Production of volatile flavour compounds during fermentation with pure cultures of Saccharomyces cerevisiae and Candida guilliermondii, Lactobacillus brevis and Lactobacillus plantarum have been investigated, using wheat doughs and several preferements as substrates. For yeast, preferments consisted of 10% (w/v) glucose, maltose and sucrose solutions, whereas for lactobacilli they consisted of supplemented and unsupplemented (3% and 10% (w/v)) glucose solutions, and a 10% (w/v) wheat flour slurry. Seven volatile compounds (acetaldehyde, acetone, ethyl acetate, ethanol, hexanal+isobutyl alcohol, and propanol) were detected when using yeasts. All these compounds, except propanol, appeared for all the substrates assayed, with ethanol as the predominant component. Generally, S. cerevisiae produced higher amounts of the different components than C. guilliermondii. Both yeasts produced larger amounts of volatile flavour compounds during fermentation in glucose and sucrose solutions than in maltose or wheat dough. In general the yeasts examined produced more flavour components than the lactobacilli. For the lactobacilli the highest number of volatile flavour compounds were observed for substrates containing flour.

Bread↗

Growth of lactobacilli, Staphylococcus aureus and Escherichia coli in normal and mastitic milk and whey.

The growth of three lactobacilli (Lactobacillus acidophilus, L. bulgaricus and L. casei), Staphylococcus aureus and Escherichia coli was followed in normal and mastitic milk and whey using the standard plate count method. L. acidophilus, L. bulgaricus 6032 and L. casei 6028 grew well in normal milk, but had decreased growth in mastitic milk if not pre-adapted in mastitic whey. S. aureus 26003 and E. coli 44102 showed enhanced growth in mastitic milk as compared with their growth in normal milk. These mastitis pathogens grew faster than the lactobacilli in both the normal milk and the mastitic milk. Among the lactobacilli, L. acidophilus and L. bulgaricus grew faster than L. casei in both types of milk samples. All the bacteria tested grew well in the normal and mastitic whey samples. However, they seemed to have enhanced growth in mastitic whey with the exception of L. casei. Pre-adaptation of the bacteria in mastitic whey in subculture markedly improved the growth of both pathogenic and non-pathogenic bacteria in mastitic milk. All the bacteria showed decreased replication in mastitic milk as compared with mastitic whey.

Animals↗

The effects of intravaginal clindamycin and metronidazole therapy on vaginal lactobacilli in patients with bacterial vaginosis.

OBJECTIVE: The purpose of this study was to determine the effects of 3 intravaginal antibacterial treatments on vaginal lactobacilli in patients with bacterial vaginosis (BV). STUDY DESIGN: Retrospective analyses were performed on Lactobacillus scores from 3 similar studies evaluating 2 2% clindamycin vaginal creams and 0.75% metronidazole gel at baseline and at 21 to 30 days in 408 patients with BV. Scores were compared using a 1-way global F test and McNemar's test. RESULTS: All groups had similar mean Lactobacillus scores at baseline (P = 0.37) and at 21 to 30 days (P = .71). The 3 groups were also comparable at both visits with respect to the distributions of scores within each group. In all groups, there was significant improvement in the percentages of patients with no lactobacilli present at 21 to 30 days compared with baseline (P < .0001 for all comparisons). CONCLUSION: Clindamycin and metronidazole promoted similar levels of restoration of vaginal lactobacilli at 21 to 30 days.

Administration, Intravaginal↗

Lactobacilli in the intestinal microbiota of Swedish infants.

Lactobacillus colonisation was examined in 112 Swedish infants. Faecal samples obtained at 1, 2, 4 and 8 weeks and at 6, 12 and 18 months of age were cultivated quantitatively on Rogosa agar. Lactobacilli were speciated by PCR and typed to the strain level by randomly amplified polymorphic DNA (RAPD). Lactobacilli reached a peak at 6 months when 45% of the infants were colonised. L. rhamnosus and L. gasseri were the most common species in this period. Colonisation by lactobacilli in general (P < 0.01) and L. rhamnosus in particular (P < 0.05) was more common in breast-fed than in weaned infants at 6 months of age. Lactobacillus isolation reached a nadir of 17% by 12 months (P < 0.0001), but increased to 31% by 18 months of age P < 0.05). The food-related species L. paracasei, L. plantarum, L. acidophilus and L. delbrueckii dominated in this second phase. A single strain persisted for at least 3 weeks in 17% of the infants during the first 6 months, most commonly L. rhamnosus. Lactobacillus population counts in colonised infants increased from 10(6.4) cfu/g at 1 week to 10(8.8) cfu/g at 6 months, and then dropped to 10(5.4) cfu/g faeces at 12 months of age. Lactobacillus colonisation was not significantly related to delivery mode, or to presence of siblings or pets in the household. Our results suggest that certain Lactobacillus species, especially L. rhamnosus, thrive in the intestinal flora of breast-fed infants. After weaning they are replaced by other Lactobacillus species of types found in food.

Breast Feeding↗

Oral cavity as natural reservoir for intestinal lactobacilli.

Ecological studies indicate that most Lactobacillus species found in the human gastrointestinal tract are likely to be transient (allochthonous), originating from either the oral cavity or food. In order to investigate if oral lactobacilli constitute a part of the faecal Lactobacillus biota, the Lactobacillus biota of saliva and faeces of three human subjects were investigated and compared at two time-points in a 3-months interval. Bacteriological culture, performed by incubation under standard (37 degrees C, anaerobic) and alternative (30 degrees C, microaerobic) conditions, as well as PCR-DGGE with group-specific primers were used to characterize the predominant lactobacilli. Cell counts varied among the subjects and over time, reaching up to 10(7)CFU/ml in saliva and 5 x 10(6)CFU/g in faecal samples. The species composition of the Lactobacillus biota of human saliva and faeces was found to be subject-specific and fluctuated to some degree, but the species Lactobacillus gasseri, Lactobacillus paracasei, Lactobacillus rhamnosus and Lactobacillus vaginalis were detected at both time-points in saliva and faecal samples of individual subjects. RAPD-PCR analysis indicated that several strains of these species were present both in the oral cavity and in the faecal samples of the same subject. Oral isolates of the species L. gasseri and L. vaginalis showing identical RAPD types were found to persist over time, suggesting that these species are autochthonous to the oral cavity. Our results together with recent published data give strong evidence that some lactobacilli found in human faeces are allochthonous to the intestine and originate from the oral cavity.

Adult↗

Examination of strains of lactobacilli for properties that may influence bacterial interference in the urinary tract.

Lactobacilli strains vary in their ability to interfere with colonization of uroepithelial cells by pathogenic organisms. Bacterial size, adherence capability, competitive exclusion and inhibition of pathogenic growth were examined in selected strains of lactobacilli to assess their relative importance. We tested adherence to uroepithelial cells of 34 lactobacillus isolates originating from the urogenital tract, dairy sources and chickens, and 1 lactobacillus strain isolated from a commercially available preparation. The ability to adhere differed greatly among the 34 strains, with a range of 8 to 74 bacteria per cell, and the commercial strain attached poorly with a mean of 15 bacteria per cell. Eleven strains of lactobacilli were selected and found to differ in length and width dimensions. These strains were found to exclude competitively with varying efficiency 6 strains of uropathogens from adhering to uroepithelial cells. The effective ability of Lactobacillus casei GR-1 to exclude the uropathogens confirmed previous findings and other strains (GR-2, GR-3 and A-60) gave a similar range of exclusion. The lactobacillus isolates varied greatly in their ability to inhibit the growth of 11 uropathogens under the conditions of an agar overlay inhibition assay. A combination score was allocated to each of the 11 lactobacillus strains based on size, adherence, exclusion and inhibition. Lactobacillus casei GR-1 attained the highest score while the commercial strain attained the lowest score. The results of this study identified 4 properties that should be examined to select lactobacillus strains before embarking upon bacterial interference studies to prevent urinary tract and other infections in humans.

Animals↗

Lactobacilli as live vaccine delivery vectors: progress and prospects.

Evidence is accumulating that lactobacilli influence the immune response in a strain-dependent manner. This immunomodulatory capacity is important for the development of the immune response, and also identifies Lactobacillus as a potent oral vaccine carrier. Most of our current knowledge of the use of lactobacilli for vaccination purposes has been obtained with tetanus toxin fragment C (TTFC) as the model antigen. This knowledge, together with our ever-increasing understanding of the immune system and recent developments in cloning and expression techniques, should enable the utilisation of antigens other than TTFC and has made the development of lactobacilli as live vaccines a realistic prospect.

Bacterial Vaccines↗

Use of PCR-based methods and PFGE for typing and monitoring homofermentative lactobacilli during Comté cheese ripening.

This study investigated the genotypic characteristics of selected and wild homofermentative thermophilic lactobacilli strains during ripening of Comté cheeses, made into two cheese plants. Both amplification and restriction analysis of the 16S rRNA gene (PCR-ARDRA) and classical biochemical tests were used to identify isolates. Diversity within homofermentative lactobacilli was not found in their species composition since the same two species Lactobacillus helveticus and L. delbrueckii susbp. lactis were isolated from cheeses. In cheeses made with natural whey starter, it appeared that the most likely sources of L. helveticus and L. delbrueckii susbp. lactis were the starter and raw milk, respectively. The examination of RAPD profiles of lactobacilli strains revealed 19 RAPD groups among 50 isolates, which were different from selected starter strains. Using RAPD, REP-PCR, and PFGE to identify selected starter strains during cheese ripening, we showed that L. helveticus decreased quickly while L. delbrueckii susbp. lactis sustained high viability during ripening. The use of selected L. delbrueckii susbp. lactis strains diminished the genetic diversity among strains isolated from cheese, probably in preventing the raw milk microflora from growing.

Bacterial Typing Techniques↗