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Probiotic properties of human lactobacilli strains to be used in the gastrointestinal tract.

AIMS: The study of two human strains of Lactobacillus to be used as probiotics in the gastrointestinal tract. METHODS AND RESULTS: The Lactobacillus acidophilus UO 001 and Lact. gasseri UO 002, were resistant to the gastrointestinal conditions (pH 2 and 3, presence of pepsin, pancreatin or bile salts), the resistance was enhanced in the presence of skimmed milk. Additionally, adhered to Caco-2 cells through glycoproteins in Lact. gasseri and carbohydrates in the case of Lact. acidophilus. These strains are able to inhibit the growth of certain enteropathogens: Salmonella, Listeria and Campylobacter without interfering with the normal microbiota of the gastrointestinal tract, as stated by using the mixed culture and the spot agar test. Finally, strongly adherent Lact. gasseri were found to inhibit the attachment of Escherichia coli O111 to intestinal Caco-2 cells under the condition of exclusion. CONCLUSIONS: These results indicate that the two strains of Lactobacillus from human origin present important properties for survival in, and colonization of, the gastrointestinal tract, that give them potential probiotic. SIGNIFICANCE AND IMPACT OF THE STUDY: Two strains of Lactobacillus isolated from human vagina of healthy premenopausal women could be promising candidates to be used in the preparation of probiotic products and for their use as health-promoting bacteria.

Adhesins, Bacterial↗

Antibacterial activity of the purified peroxidase from human parotid saliva.

The peroxidase of human parotid saliva has been purified by concentration, gel filtration on Sephadex G-200, and ion exchange chromatography on Amberlite CG-50. The purified product was devoid of amylase activity, lysozyme activity, and immunoglobulin A (IgA). However, it had an inhibitory effect on the growth of Lactobacillus acidophilus in complete growth medium and on lysine accumulation by L. acidophilus in a buffer-glucose medium, when combined with thiocyanate ions. The concentrations of peroxidase and thiocyanate ions employed were within the range found in saliva. The fractions which contained IgA did not have an anti-bacterial effect on L. acidophilus under the conditions employed. Parotid saliva also contained low molecular weight inhibitors of peroxidase activity. These studies support the involvement of the salivary peroxidase in an antibacterial system in saliva.

Adult↗

An improved method of microencapsulation and its evaluation to protect Lactobacillus spp. in simulated gastric conditions.

An improved method of microencapsulation was developed to increase the efficacy of capsules in protecting the encapsulated bacteria under simulated gastric conditions. Lactobacillus acidophilus CSCC 2400 was encapsulated in calcium alginate and tested for its survival in simulated gastric conditions. The effects of different capsule sizes (200, 450, 1000 microm), different sodium alginate concentrations (0.75%, 1%, 1.5%, 1.8% and 2% w/v) and different concentrations of calcium chloride (0.1, 0.2, 1.0 M) on the viability of encapsulated bacteria were investigated. The viability of the cells in the microcapsules increased with an increase in alginate capsule size and gel concentration. There was no significant difference (p>0.05) in the viability of encapsulated cells when the concentration of calcium chloride was increased. Increase in cell load during encapsulation increased the number of bacterial survivors at the end of 3-h incubation in simulated gastric conditions. Hardening the capsule in calcium chloride solution for a longer time (8 h) had no impact on increasing the viability of encapsulated bacteria in a simulated gastric environment. The release of encapsulated cells at different phosphate buffer concentrations was also studied. When encapsulated L. acidophilus CSCC 2400 and L. acidophilus CSCC 2409 were subjected to low pH (pH 2) and high bile concentration (1.0% bile) under optimal encapsulation conditions (1.8% (w/v) alginate, 10(9) CFU/ml, 30 min hardening in 0.1 M CaCl(2) and capsule size 450 microm), there was a significant increase (p<0.05) in viable cell counts, compared to the free cells under similar conditions. Thus the encapsulation method described in this study may be effectively used to protect the lactobacillus from adverse gastric conditions.

Alginates↗

Probiotics, cecal microflora, and aberrant crypts in the rat colon.

Our hypothesis was that administration of bifidobacteria, Lactobacillus acidophilus or both to rats will minimize the numbers of aberrant crypts in the distal colon that develop in response to the carcinogen 1,2-dimethylhydrazine (DMH). A series of experiments was designed to test this hypothesis where the treatments used were as follows: skim milk controls (Skim-Basal), skim milk + bifidobacteria (Bifido-Basal), skim milk + fructooligosaccharide (Skim-FOS), and skim milk + bifidobacteria + fructooligosaccharide (Bifido-FOS). In two experiments, bifido-bacteria + FOS administration significantly decreased the number of aberrant crypts that developed, but there was no clear relationship of aberrant crypts to numbers of bifidobacteria or Clostridium perfringens. In the third experiment, the Bifido-FOS treatment led to significantly fewer aberrant crypts and aberrant crypt foci than the Bifido-Basal treatment. The Skim-FOS group had significantly more cecal bifidobacteria than the Skim-Basal group and significantly fewer C. perfringens than the Skim-Basal and Bifido-Basal. In a fourth experiment, L. acidophilus was added as an additional treatment. The number of aberrant crypts was not significantly different among the groups. However, the number of C. perfringens was significantly decreased by the addition of bifidobacteria, L. acidophilus or the combination of the two, whereas the numbers of bifidobacteria and L. acidophilus were not affected by treatment. A significant correlation (R2 = 0.84, P < 0.01) was noted between the body weight of rats at DMH administration and the magnitude of the difference in aberrant crypts between the Skim-Basal rats and the Bifido-FOS rats. The results suggest that there is variability in the effects of bifidobacteria and L. acidophilus administration on both aberrant crypt formation and C. perfringens.

Animals↗

Antimicrobial substantivity of cavity disinfectants.

This study involved a comparative examination of different disinfectant solutions and their antimicrobial substantivity against Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. All of the disinfectants containing chlorhexidine and benzalkonium chloride demonstrated substantive antibacterial activity. Chlorhexidine-based solutions displayed the longest and most effective antimicrobial activity.

Analysis of Variance↗

Studies on antimutagenic effect of milk cultured with lactic acid bacteria on the Trp-P2-induced mutagenicity to TA98 strain of Salmonella typhimurium.

The inhibitory effects of cultured milk using 76 strains of lactic acid bacteria isolated from milk products were investigated on the mutagenicity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P2), a tryptophan pyrolysate for Salmonella typhimurium TA98. Each cultured milk sample displayed its characteristic antimutagenic effect against the mutagenicity of Trp-P2. The milk cultured with Lactobacillus acidophilus LA106 (LA2) showed the highest inhibition of 82.1% among the strains used. Milk samples cultured with Lactococcus lactis subsp. lactis, Lll103 (10-3) and Lll102 (KM) also exhibited higher inhibition percentages.

Animals↗

Effectiveness of current therapy of bacterial vaginosis.

The study was conducted in order to evaluate effectiveness of the treatment of bacterial vaginosis (BV) with different therapeutic regimes according to recommendations of the World Health Organization (WHO). During a one-year period (February 2000-February 2001) the Sexually Transmitted Diseases (STD) Center was visited by 482 women aged 14-51. The diagnosis of BV was established by standard methods: Amsel's clinical criteria and Gram stain of vaginal discharge. The first-line treatment was oral Metronidazole 2 g single dose. Second line was Metronidazole 500 mg twice daily orally for 7 days or oral Clindamycin 300 mg twice daily for seven days. BV was confirmed in 74 women (15.4%). Most often it was observed in women aged 17-30 years of age. Thirty-three (44.6% of total) were young women 14-21 years of age. Thirty-one (42%) women received a follow-up examination and of those, 11 (38.7%) needed a repeat treatment for BV due to unsatisfactory results of this treatment. It is concluded that treatment of BV with standard methods was not always effective with no significant difference between women under 21 years and older women found in regards to response to treatment. Besides antibiotic treatment, the so-called Probiotics (Lactobacillus acidophilus) can be taken into consideration as an alternative treatment. Additional research about the therapeutic effect of this type of drugs is needed.

Adolescent↗

Augmentation of macrophage phagocytic activity by cell-free extracts of selected lactic acid-producing bacteria.

Oral and intraperitoneal administration of lactic acid-producing bacteria can significantly augment the immune response in murine models; however, the immunopotentiating effects in these studies differ significantly. Murine macrophagelike cell line J774 was cultured in the presence of cell-free extracts of Lactobacillus acidophilus and Bifidobacterium longum, and the effect on macrophage function was evaluated by measurement of synthesis of selected enzymes and their ability to take up either acrylamide particles or live Salmonella typhimurium. Lysozyme activity of J774 cells was significantly decreased by cell-free extracts of B. longum, but not of L. acidophilus, whereas extracts of both strains induced morphological changes and significantly enhanced phagocytosis of inert particles or viable Salmonella. Whole cell extracts of lactic acid-producing bacteria are therefore capable of altering macrophage function in a strain-dependent manner.

Animals↗

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↗

Evaluation of antinfective activity of an association bifidobacterium/lactobacillus in mouse intestine.

The present research aimed at studying the action of an association of Bifidobacterium bifidum and Lactobacillus acidophilus, in controlling an experimental severe infection by Salmonella enteritidis administered in mouse per os. The behaviour of some parameters was undertaken, checking for the pH of intestinal content; the condition of the colonization in the intestinal wall by means of scanning electron microscopy and plates cultures; the presence of antibodies IgA in intestinal content; the index of mortality in the diversely treated animal's groups. The reported data show a string incidence of the administration of Bifidobacterium and Lactobacillus in increasing the animal's resistance against the lethal infection.

Animals↗

Immunoelectron microscopic studies on the localization of peptidoglycan peptide subunit pentapeptides in bacterial cell walls.

The peptide subunit pentapeptide H-L-Ala-D-Glu(L-Lys-D-Ala-D-Ala-OH)-NH2 of peptidoglycan was localized in the cell walls of several Gram-positive bacteria employing the indirect immunoferritin technique. Specific antibodies to the D-alanyl-D-alanine moiety of non-crosslinked peptide subunit pentapeptide were raised in rabbits by immunization with synthetic immunogen albumin-(CH2CO-Gly-L-Ala-L-Ala-D-Ala-D-Ala-OH)39. Specificity of these antibodies for the peptide subunit pentapeptide and not for the peptide subunit tetrapeptide was corroborated in a Farr-type radio-active hapten binding assay. Specificity of labelling with ferritin was established by immunoelectron microscopic controls, and by the excellent correlation between specific labelling of cells with ferritin and the particular peptidoglycan primary structure of bacterial strains investigated. Cells of Lactobacillus gasseri, Streptococcus pyogenes and Staphylococcus aureus revealing non-crosslinked peptide subunit pentapeptides in their peptidoglycans could specifically be labelled. Lactobacillus acidophilus and Bacillus subtilis, on the contrary, missing such pentapeptides, failed in labelling. The implication of this method to possibly localize the points of attack of penicillin or cycloserine is discussed.

Bacillus subtilis↗

Microorganisms and characteristics of laban.

Laban had a titratable acidity of about 1.0%, a pH of 4.25, an ethanol content of 1.25%, and contained 4.2 mug acetaldehyde and 34 mug acetoin/ml. There was no diacetyl. Five microorganisms, classified as Streptococcus thermophilus, Lactobacillus acidophilus, Leuconostoc lactis, Kluyveromyces fragilis, and Saccharomyces cerevisiae, were responsible for the fermentation. Streptococcus thermophilus and L. acidophilus were responsible for acid production with S. thermophilus producing acid more rapidly. Most of the acetaldehyde was produced by K. fragilis, little ethanol was found in absence of S. cerevisiae, and the acetoin was producted by S. thermophilus.

Animals↗

The effect of the addition of proteases and glucanases during yeast autolysis on the production and properties of yeast extracts.

Yeast extracts (YE) were produced with the addition of proteases or glucanases during bakers' yeast (Saccharomyces cerevisiae) autolysis. Chemical composition, physical properties, and biological value of the YE were examined. Proteases had the highest impact on the turbidity and filterability of YE. All 11 proteases and two glucanases increased YE yields (% yeast solids solubilized) obtained from heated (80 degrees C/15 min) bakers' yeast creams (BYC). However, when proteases were added to native (unheated) BYC during autolysis, few increased YE yields, with papain being the most effective. The increased yields were generally related to increased levels of total nitrogen (TN) and alpha-amino nitrogen (alpha-AN) in the YE. Media were supplemented with the various yeast extracts, and the highest growth rates (mumax) and biomass values (ODmax) of Lactobacillus acidophilus were noted. The best growth was obtained with YE produced with native BYC treated with a fungal protease, and results of this study show that some enzymes could be used to produce improved YE for microbiological media.

Biomass↗

Evaluation of an avian-specific probiotic to reduce the colonization and shedding of Campylobacter jejuni in broilers.

Campylobacter jejuni has often been responsible for human gastroenteritis. Poultry have often been implicated as a source for these human infections. Intestinal colonization of C. jejuni in the chicken plays a role in carcass contamination during slaughter. Thus, reducing C. jejuni colonization in chickens can potentially reduce the incidence of C. jejuni infections in humans. The use of probiotics to competitively exclude the colonization of intestinal pathogens has been proposed for poultry. Hence, the purpose of this study was to evaluate the use of an avian-specific probiotic containing Lactobacillus acidophilus and Streptococcus faecium for reducing the shedding and colonization of C. jejuni in the chicken intestinal tract. Day-old chicks were randomly allocated into either a probiotic-treated group or a control group. The treated group was given probiotic from day 1 to day 3, and the control group was not given any probiotic. Six hours after the first oral administration of probiotics (treatment) or double distilled water (control), these chicks were challenged with C. jejuni. The frequency of the C. jejuni shedding was monitored until market age. Intestinal colonization was determined for the two experimental groups at slaughter. Results indicated that chickens given probiotics from day 1 to day 3 had a 70% reduction in the frequency of C. jejuni shedding in colonized chicks (P = 0.0001) and a 27% reduction in jejunal colonization in colonized chicks (P = 0.0001) at slaughter when compared with the control group. Thus, the use of the avian-specific probiotic containing L. acidophilus and S. faecium can reduce the colonization and frequency of fecal shedding of C. jejuni in market-aged broilers.

Administration, Oral↗

Experimental study of the influence of intestinal flora on the healing of intestinal anastomoses.

BACKGROUND: The beneficial effects of the normal intestinal flora on wound healing in the skin have already been confirmed, and this study attempted to elucidate the influence of the intestinal flora on the healing process in intestinal anastomoses. METHODS: Five groups of rats were studied: germ-free, conventional, monocontaminated with Lactobacillus acidophilus La5 or Escherichia coli X7 and ex-germ-free (conventionalized). All animals underwent ileal and colonic resections followed by anastomoses. Seven days later they were killed and the bursting pressure and hydroxyproline concentration of the anastomoses were measured. The microbiological status of the animals was confirmed weekly. RESULTS: No bacteria were detected in the germ-free rats and no other bacteria were found in the monocontaminated animals. Conventional rats had a significantly higher anastomotic bursting pressure both in the ileum compared with rats monocontaminated with L. acidophilus, and in the colon compared with germ-free rats. The ex-germ-free rats also showed a significantly higher bursting pressure than germ-free animals and rats monocontaminated with either L. acidophilus or E. coli in the ileum and colon. CONCLUSION: The presence of the intestinal flora enhanced the healing of intestinal anastomoses. The data suggest that this effect depends on differences in the types of bacteria in the intestine.

Anastomosis, Surgical↗

Characterization and DNA homology of Lactobacillus strains isolated from pig intestine.

Twenty strains of the genus Lactobacillus were isolated from pig intestines and characterized with phenotypic tests. Eleven of these strains, together with selected reference strains, were subjected to DNA homology studies. Three major groups could be distinguished by biochemical/physiological tests and by DNA homology studies: one homofermentative group of the subgenus Thermobacterium and two heterofermentative groups. The DNA homology studies revealed that strains from the homofermentative group were related to Lactobacillus acidophilus strain VPI 1754, but showed a low relationship to the type strain of Lact. acidophilus. One One group of the heterofermentative strains was related to the type strain of Lact. reuteri; the other group, consisting of three strains, showed a low relationship to all reference strains used. These three strains had the unusual property of producing succinic acid in large amounts.

Animals↗

Antibacterial activity of different generation dentin-bonding systems.

OBJECTIVES: The aim of this in vitro study was to investigate the antibacterial activities of different generation dentin-bonding systems. METHOD AND MATERIALS: The antibacterial activities of dentin-bonding systems Optibond FL Primer, Single Bond, Clearfil SE Bond Primer, and Prompt-L-Pop were evaluated against Streptococcus mutans, Streptococcus salivarius, Lactobacillus casei, and Lactobacillus acidophilus. Cervitec (1% chlorhexidine varnish) was also examined as a positive control material. Disk diffusion tests with filter paper disks (n = 10) containing a drop of each material (20 microL) were used. After incubation at 37 degrees C for 48 hours, the growth inhibition zones were measured in millimeters. RESULTS: Of all the materials tested, Optibond FL Primer, Clearfil SE Bond Primer, and Prompt-LPop showed larger growth inhibition zones than the control material for all bacterial strains. No antibacterial effect was noted for Single Bond. The results indicated that Optibond FL Primer had the strongest effect against the S mutans and L casei, and Clearfil SE Bond Primer produced the largest inhibition zone for S salivarius and L acidophilus among the test materials. CONCLUSION: The antibacterial effects observed for the tested different generation dentin-bonding systems may be related to the acidic nature of the materials.

Analysis of Variance↗