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PubMed1998

[Antibacterial activity of lactobacilli].

The antagonistic action of lactobacilli is an important factor in the protection of the vagina of fertile women from infection by other microorganisms. In the present study the authors investigated 17 strains of lactobacilli, incl. 11 of vaginal origin. The objective was to investigate in more detail the antibacterial activity of lactobacilli and to attempt to assess substances responsible for inhibition. The investigated lactobacilli inhibited some strains of Escherichia coli, Serratia marcescens, Shigella boydii, Staphylococcus aureus, Listeria monocytogenes, Listeria innocua and Listeria ivanovii with different intensity. The authors provided evidence that inhibition is due mainly to organic acids and to a lesser extent to bacteriocins. The authors assessed also the effect of enterobacteria on lactobacilli but did not observe any inhibition of lactobacilli.

Antibiosis↗
PubMedDate not supplied

Genetics of lactobacilli: plasmids and gene expression.

This paper reviews the present knowledge of the structure and properties of small (< 5 kb) plasmids present in Lactobacillus spp. The data show that plasmids from Lactobacillus spp., like many plasmids from other Gram-positive bacteria, display a modular organization and replicate by a mechanism of rolling circle replication. Structurally, plasmids from lactobacilli are closely related to plasmids from other Gram-positive bacteria. They contain elements (plus- and minus origin of replication, element(s) for control of plasmid replication, mobilization function) showing extensive similarity to analogous elements in plasmids from these other organisms. It is believed that lactobacilli have acquired such elements by intra- and/or intergenic transfer mechanisms. The first part of the review is concluded with a description of plasmid vectors with a Lactobacillus replicon and integrative vectors, including data concerning their structural and segregational stability. In the second part of this review we describe the progress that has been made during the last few years in identifying and characterizing elements that control expression of genetic information in lactobacilli. Based on the sequence of eleven identified and twenty presumed promoters, some preliminary conclusions can be drawn regarding the structure of Lactobacillus promoters. A typical Lactobacillus promoter shows significant similarity to promoters from E. coli and B. subtilis. An analysis of published sequences of seventy genes indicates that the region encompassing the translation start codon AUG also shows extensive similarity to that of E. coli and B. subtilis. Codon usage of Lactobacillus genes is not random and shows interspecies as well as intraspecies heterogeneity. Interspecies differences may, in part, be explained by differences in G+C content of different lactobacilli. Differences in gene expression levels can, to a large extent, account for intraspecies differences of codon usage bias. Finally, we review the knowledge that has become available concerning protein secretion and heterologous gene expression in lactobacilli. This part is concluded with a compilation of data on the expression in Lactobacillus of heterologous genes under the control of their own promoter or under control of a Lactobacillus promoter.

Bacillus subtilis↗
PubMed2004

Presence of drug resistance in intestinal lactobacilli of dairy and human origin in Turkey.

The prevalence of different resistance genes was investigated in lactobacilli of human and dairy origin by PCR. The presence of erm, van, tet, and cat-TC genes were determined in 16 raw milk, 15 cream, 10 yogurt, 50 hand-made cheese, and 20 industrially produced white-cheese samples of dairy origin and 16 mouth, 32 fecal, and 36 vaginal samples from different subjects of human origin. Lactobacilli of dairy and human origin were found to carry only erm(B) and tet(M) genes. The majority of the isolates, Lactobacillus crispatus (61), Lactobacillus gasseri (49), Lactobacillus plantarum (80) studied were found to harbor either erm(B) or tet(M) gene or both. No resistant lactobacilli was found in raw-milk and cream samples. All the human fecal samples and the majority of vaginal (29 of 36) and mouth (10 of 14) samples were found to carry the resistance genes. While a third of the hand-made cheeses carried resistant lactobacilli only one industrially produced cheese was found to carry resistant lactobacilli. Furthermore, the genes were found in the non-starter species, Lactobacillus acidophilus and Lb. plantarum, indicating that industrially produced cheeses in this respect could be considered more favorable. These results indicate that drug resistance seems to be very common in Turkey. Even though the number of dairy samples harboring the resistance genes (17 of 111) is smaller in regards to human samples, 10% of them were still found to carry the resistance genes as well. The presence of the resistance genes in majority of the samples of human origin and in minority of the samples of dairy origin indicates that drug resistance may be acquired in the intestinal tract during passage and spread to dairy products by the hands of workers during production.

Animals↗
PubMed2006

Rapid discrimination of lactobacilli isolated from kefir grains by FT-IR spectroscopy.

Fourier transform infrared (FT-IR) spectroscopy was used in combination with multivariate statistical analysis for differentiation of lactic bacteria isolated from kefir grains. Twelve reference strains and 42 lactobacilli isolates from four local kefir grains, previously identified by biochemical traditional techniques at species level were included in this study. The spectra were analysed by hierarchical clustering analysis (HCA) using Pearson's product-moment correlation coefficient and Ward's algorithm. The differentiation between homo- and heterofermentative lactobacilli, proposed as a first level in the classification scheme, was performed with vector normalized first derivatives spectra in the windows 1789-1700, 1059-935, 3000-2927 and 896-833 cm(-1). For heterofermentative lactobacilli the windows 1780-1750, 1500-1200, 2950-2930 and 900-700 cm(-1) were found to contribute to the maximal separation among L. kefir, L. parakefir and Lactobacillus brevis. It was also demonstrated that although this model was robust against small variations in growth temperature (+/-5 degrees C) and growth time (+/-5 h), the make of culture medium used (Biokar or Difco) affected the separation of heterofermentative lactobacilli at species level. For homofermentative lactobacilli the spectral regions 1230-900, 1777-1690, 1357-1240 and 2960-2870 cm(-1), were selected for discrimination among 5 different species that are normally present in kefir grains: L. plantarum, L. acidophilus, L. kefirgranum, L. kefiranofaciens and L. cassei. The classification and discrimination schemes proposed in this work completely matched with the identification obtained by classical biochemical techniques at species level.

Cluster Analysis↗
PubMed1981

Lactobacilli do not cause frequency and dysuria syndrome.

Mid-stream specimens (MSU) of urine were collected from 142 healthy women (pregnant and non-pregnant) and cultured for lactobacilli and other fastidious bacteria. The latter either require CO2 or are obligate anaerobes. Lactobacilli were present in counts of 10(4)/ml or more in 34.8% of the women, and in counts of 10(5)/ml or more in 20.2%. Besides lactobacilli, which were the bacteria most frequently isolated, anaerobic gram-positive cocci (peptococci and peptostreptococci) were often found. This flora is typical of that of the lower vagina, and none of these women had either symptoms of urinary infection of pyuria. Therefore, the bacteria isolated were commensals or contaminants. Cultures of MSUs taken from 26 women with symptoms of dysuria and/or frequency, but without significant numbers of conventional pathogens such as Escherichia coli, contained commensals and contaminants of the same variety and in similar numbers. Urine samples from 50% of these patients contained at least 10(4) lactobacilli/ml and 27% had 10(5) or more/ml. Lactobacilli were absent from the suprapubic urine specimens cultured from a further 44 women. There was no significant difference between the isolation rate of lactobacilli in urine cultures from healthy women and the rate in women with dysuria and frequency.

Chlamydia Infections↗
PubMed1998

Inhibition of bacterial pathogens by lactobacilli.

Lactobacilli produce many antimicrobial substances including organic acids, hydrogen peroxide and bacteriocins. Antagonistic activity of lactobacilli is an important factor in the protection of the vagina of fertile women against infection by certain pathogens. In the present study, we investigated 17 strains of lactobacilli, including 11 strains of vaginal origin. The aim was to investigate in more detail the antibacterial activity of lactobacilli and to attempt to assess substances responsible for inhibition. The investigated lactobacilli inhibited some strains of Escherichia coli, Serratia marcescens, Shigella boydii, Listeria monocytogenes, Listeria ivanovii, Listeria innocua and Staphylococcus aureus. We have provided evidence that inhibition is due mainly to organic acids and to a lesser extent, to bacteriocins.

Agar↗
PubMed2006

Molecular identification and typing of lactobacilli isolated from kefir grains.

Seventeen heterofermentative lactobacilli isolated from kefir grains were characterized by molecular methods. Bacterial isolates were identified by amplification of 16S rRNA gene and analysis by Amplified Ribosomal DNA Restriction Analysis (ARDRA), using the restriction enzymes Hae III, Dde I, and Hinf I. ARDRA analysis of lactobacilli isolates showed, for each enzyme used, a same banding pattern between the heterofermentative lactobacilli and the reference strains Lactobacillus kefir JCM 5818 and Lb. kefir ATCC 8007. Other reference lactobacilli and one homofermentative isolate showed differences in at least one of these patterns. The 16S-23S rRNA spacer region was also used to discriminate the bacterial isolates at the species level. The data obtained from the analysis of spacer region confirmed that sequencing of this genome region is a good tool for a reliable identification of members of Lb. kefir species. Genotyping of isolates was performed by Random Amplified Polymorphic DNA (RAPD-PCR) analysis using M13, Coc, ERIC-2 and 1254 primers. Patterns obtained allowed the differentiation of isolates in three groups. The three clusters showed by RAPD-PCR analysis could be correlated with at least three different strains of Lb. kefir species in the group of heterofermentative lactobacilli isolates obtained from Argentinian kefir grains.

Bacterial Typing Techniques↗
PubMed2002

16S ribosomal DNA analysis of the faecal lactobacilli composition of human subjects consuming a probiotic strain Lactobacillus acidophilus NCFM.

AIMS: The aims of this study were to evaluate the ability of exogenous Lactobacillus acidophilus strain NCFM to survive through the human gastro-intestinal (GI) tract, and to evaluate the selectivity of Rogosa SL medium for faecal lactobacilli. METHODS AND RESULTS: The composition of the faecal lactobacilli of 10 healthy subjects was monitored for two weeks prior to, two weeks during and two weeks after the administration of the Lact. acidophilus strain NCFM consumed with skim milk (daily dose 10(10) viable cells). Fresh faecal samples were collected, processed and cultured on Rogosa SL selective medium for lactobacilli enumeration. Colonies demonstrating various morphologies were identified and purified for 16S ribosomal DNA sequence analysis for speciation of colonial genotype. The species composition of cultivable faecal lactobacilli changed considerably during consumption of the strain NCFM. CONCLUSIONS: The probiotic Lact. acidophilus strain NCFM can survive through the human GI tract, but cannot colonize itself during the two-week consumption. Rogosa SL medium is selective for faecal lactobacilli. However, genetic analysis is required for colony speciation. SIGNIFICANCE AND IMPACT OF THE STUDY: It is demonstrated that continuous consumption is necessary to maintain a high population of the probiotic strain, and that the Rogosa SL medium is reliable.

Adult↗
PubMed2003

Lactobacilli attenuate bacteremia and endotoxemia associated with severe intra-abdominal infection.

BACKGROUND: Systemic administration of antibiotics or selective decontamination is frequently used in the prophylaxis and treatment of infections originating from the gastrointestinal flora. In this study, we wanted to compare the protective effect of enteral administration of lactobacilli to gentamicin against severe intra-abdominal infection. METHODS: Male Sprague-Dawley rats underwent cecal ligation and puncture (CLP). Rats were pretreated with saline, Lactobacillus R2LC, and gentamicin. Bacterial growth and endotoxin levels in the blood, reticuloendothelial system (RES)-function, and intestinal transit were determined up to 24 hours after CLP. RESULTS: CLP-provoked bacteremia was significantly reduced by 48% and 55% in lactobacilli- and gentamicin-treated rats, respectively. Notably, CLP-induced endotoxemia was abolished at 12 hours, and reduced by 47% at 24 hours, in rats pretreated with lactobacilli. Gentamicin reduced endotoxin levels provoked by CLP by 86% at 12 hours, but had no effect at 24 hours. Lactobacilli had no effect on the clearance of Escherichia coli (E coli) from the blood, whereas intestinal transit was increased in lactobacilli-treated animals, suggesting that the beneficial effect of Lactobacillus R2LC is not related to an increase of phagocytic capacity but may rather be partly attributable to an enhanced intestinal motility. CONCLUSION: Enteral administration of Lactobacillus R2LC attenuates bacteremia and endotoxemia associated with intra-abdominal infection in rats.

Abdominal Abscess↗
PubMed1988

Evidence for the presence of heat-stable protein (HPr) and ATP-dependent HPr kinase in heterofermentative lactobacilli lacking phosphoenolpyruvate:glycose phosphotransferase activity.

An analysis of the biochemical basis for the lack of phosphoenolpyruvate:glycose phosphotransferase activity in heterofermentative lactobacilli was carried out. Extracts of Lactobacillus brevis and Lactobacillus buchneri failed to reconstitute phosphotransferase activity of extracts of Staphylococcus aureus mutants impaired in the phosphotransferase system due to the absence of enzyme I, enzyme IILac, or enzyme IIILac activity, suggesting that these lactobacilli lack those phosphotransferase system components. In contrast, complementation tests with an extract of a S. aureus mutant deficient in heat-stable protein (HPr) indicated the presence of HPr activity in heterofermentative lactobacilli. The HPr of L. brevis was purified and shown to have properties similar to those of a typical HPr. In addition, L. brevis possesses an ATP-dependent protein kinase that phosphorylates a serine residue of the endogenous HPr as well as other HPrs of Gram-positive origin. The kinase activity is markedly stimulated by phosphorylated compounds related to sugar metabolism and is negatively modulated by orthophosphate, pyrophosphate, or arsenate and by a low molecular weight endogenous factor. In keeping with the idea of a regulatory role for the phosphorylation of HPr in lactobacilli, a HPr[Ser(P)] phosphatase activity in L. brevis was also demonstrated. On the basis of the finding of HPr and a system for its reversible covalent modification in an organism devoid of a functional phosphotransferase system we propose that, in lactobacilli, HPr has a role in the regulation of pathways other than the phosphotransferase system.

Arsenates↗
PubMed2006

Salivary mutans streptococci and lactobacilli levels after ingestion of the probiotic bacterium Lactobacillus reuteri ATCC 55730 by straws or tablets.

OBJECTIVE: Previous studies have suggested that lactobacilli-derived probiotics in dairy products may affect oral ecology, but the impact of different vehicles of ingestion has received little attention. The aim of the present study was to investigate the effect of the probiotic bacterium Lactobacillus reuteri ATCC 55730 on the levels of salivary mutans streptococci and lactobacilli in young adults when ingested by two different delivery systems. MATERIAL AND METHODS: The material comprised 120 healthy young adults (21-24 years) and a placebo-controlled study design with parallel arms was utilized. The subjects were randomly assigned to four equally sized groups: group A drank 200 ml of water through a prepared straw containing L. reuteri ATCC 55730 once daily for 3 weeks, while group B took 200 ml water through a placebo straw during the same period. Group C was given one tablet containing L. reuteri ATCC 55730 once daily for 3 weeks, while group D received placebo tablets without bacteria. Salivary mutans streptococci and lactobacilli were enumerated with chair-side kits at baseline and 1 day after the final ingestion. RESULTS: A statistically significant reduction of the mutans streptococci levels was recorded after ingestion of the probiotic bacteria via the straw (p<0.05) and the tablets (p<0.01), which was in contrast to the placebo controls. A similar but non-significant trend was seen for lactobacilli. CONCLUSIONS: A short-term daily ingestion of lactobacilli-derived probiotics delivered by prepared straws or lozenges reduced the levels of salivary mutans streptococci in young adults.

Adult↗
PubMed2002

Vaginal lactobacilli: self- and co-aggregating ability.

Lactic acid bacteria are the dominant bacteria of the vaginal tract in healthy women. Lactobacillus species form a barrier population that protects from pathogen colonisation by mechanisms that include adhesion to epithelial surfaces, self-aggregation and co-aggregation. In this study, factors involved in the self-aggregating ability of vaginal lactobacilli and in the co-aggregation of these microorganisms with Candida spp. are studied. Both self-aggregation and co-aggregation are monitored quantitatively by the decrease in the absorbance of suspensions of the microorganisms and qualitatively by light microscopy. The self-aggregating ability of four vaginal lactobacilli was shown to be caused by a peptide or protein sensitive to trypsin. However, in self-aggregating Lactobacillus acidophilus CRL 1294 the factor was resistant to trypsin and sensitive to pepsin. Among self-aggregating lactobacilli, L. acidophilus CRL 1294 and L. salivarius CRL 1328 were able to co-aggregate with Candida spp. The co-aggregating factor for both strains proved to be peptide of the surface and a peptide on the bacterial surface, while the receptor on the yeast was a carbohydrate. Co-aggregation of both lactobacilli and Candida spp. was inhibited by the addition of mannose but was not affected by other carbohydrates. Self and co-aggregation factors were not able to induce aggregation in non-aggregating lactobacilli.

Bacterial Adhesion↗
PubMed1998

Inverse association of H2O2-producing lactobacilli and vaginal Escherichia coli colonization in women with recurrent urinary tract infections.

Women with recurrent urinary tract infection (UTI) often demonstrate persistent vaginal colonization with Escherichia coli. Since strains of lactobacilli that produce hydrogen peroxide inhibit the growth of E. coli, the absence of these strains may predispose to E. coli colonization and to UTI. To test this hypothesis, vaginal introital cultures were obtained from 140 women, 65 with recurrent UTI (case-patients) and 75 without (controls). Vaginal E. coli colonization was significantly more frequent in case-patients than controls (35% vs. 11%; P < .001) and in women without H2O2-positive lactobacilli than in women with (odds ratio [OR], 4.0; P = .01). Spermicide use was associated with greater risk of vaginal E. coli colonization (OR, 12.5; P < .001) and with absence of H2O2-positive lactobacilli (OR, 2.9; P = .04). The inverse association between H2O2-positive lactobacilli and vaginal E. coli colonization remained in case-patients after controlling for spermicide use (OR, 6.5; P = .02). Thus, absence of H2O2-positive lactobacilli may be important in the pathogenesis of recurrent UTI by facilitating E. coli introital colonization.

Adult↗
PubMed1996

Hydrogen peroxide-producing lactobacilli and acquisition of vaginal infections.

This cohort study of 182 women attending a sexually transmitted disease clinic evaluated the hypothesis that women colonized by lactobacilli have decreased acquisition of vaginal infections. During a 2-year follow-up, 50 women acquired bacterial vaginosis (BV), 25 acquired symptomatic vulvovaginal candidiasis (VVC), and 7 acquired vaginal trichomoniasis. By multivariate analysis, utilizing Cox proportional hazards modeling with time-dependent covariates, acquisition of BV was independently associated with lack of vaginal H2O2-producing lactobacilli (hazard ratio [HR] = 4.0, P < .001) or presence of only non-H2O2-producing lactobacilli (HR = 2.2, P = .02). Acquisition of BV was associated with having a new sex partner (HR = 2.5, P = .004) and with douching for hygiene (HR = 2.1, P = .05). Absence of lactobacilli did not increase acquisition of VVC. Trichomoniasis was associated only with having a new sex partner (HR = 4.7, P = .05). These results support the hypothesis that H2O2-producing vaginal lactobacilli protect against acquisition of BV but do not protect against VVC or vaginal trichomoniasis.

Adolescent↗
PubMed1998

Continuous culture selection of bifidobacteria and lactobacilli from human faecal samples using fructooligosaccharide as selective substrate.

The human large intestine contains a large and diverse population of bacteria. Certain genera, namely Bifidobacterium and Lactobacillus, are thought to exert health-promoting effects. Prebiotics such as fructooligosaccharides (FOS) have been shown to stimulate the growth of endogenous bifidobacteria. In this study, changes of lactic acid producing bacteria in continuous culture fermentors (semi-defined, anaerobic medium containing 5 g 1(-1) FOS, dilution rate of 0.1 h-1, pH 5.5) were followed over a 21 d period after inoculation with blended human faeces from four healthy adults. Samples were also taken every 3 d for influent/effluent FOS, short chain fatty acid (SCFA), lactate and microbiological analyses. Results showed that SCFA concentrations decreased abruptly 1 d after inoculation while lactate concentrations increased. Classical methods of enumeration using selective media showed that the proportion of total culturable count represented by bifidobacteria and lactobacilli increased from 11.9% on day 1 to 98.1% on day 21. However, molecular methods using genus-specific 16S rRNA oligonucleotide probes indicated that the bifidobacterial population maintained a level between 10 and 20% of total 16S rRNA during the first 6 d and disappeared rapidly when the maximum concentration of lactate was reached. Lactobacilli, which were initially present in low numbers, increased until day 9 and remained at high levels (20-42% of total 16S rRNA) to day 21, with the exception of day 18. Although FOS has usually been regarded as a selective substrate for bifidobacteria, these observations suggest that: (1) lactobacilli are also able to use FOS, (2) lactobacilli can out-compete bifidobacteria in continuous culture at pH 5.2-5.4 when FOS is the primary carbon and energy source, and (3) bifidobacteria can grow faster on FOS than lactobacilli under controlled conditions.

Adult↗
PubMed2007

Quantitative evaluation of adhesion of lactobacilli isolated from human intestinal tissues to human colonic mucin using surface plasmon resonance (BIACORE assay).

AIMS: To isolate lactobacilli from the mucus layer of the human intestine and evaluate their adhesion abilities using a BIACORE assay. METHODS AND RESULTS: Thirty strains of lactobacilli were isolated from the mucus layer of normal human intestinal tissues using conventional plate culture. The strains were identified using homology comparisons of the 16S rDNA sequence to databases as Lactobacillus salivarius (26%), Lactobacillus fermentum (13%), Lactobacillus gasseri (10%), Lactobacillus paracasei (7%), Lactobacillus casei (3%), Lactobacillus mucosae (3%) and Lactobacillus plantarum (3%). Lactobacillus plantarum LA 318 shows the highest adhesion to human colonic mucin (HCM) using the BIACORE assay at 115.30 +/- 12.37 resonance unit (RU). The adhesion of cell wall surface proteins from strain LA 318 was significantly higher to HCM than to bovine serum albumin (BSA; P < 0.05). CONCLUSIONS: We isolated 30 strains of lactobacilli. Lactobacillus salivarius was the predominant species of lactobacilli isolated in this study. The adhesion of strain LA 318 isolated from human transverse colon to its mucin was shown. The adhesion could be mediated by lectin-like components on the bacterial cell surface. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study where lactobacilli were isolated from human intestinal tissues and shown to adhere to HCM.

Bacterial Adhesion↗
PubMed1989

Mutans streptococci and lactobacilli in saliva from children with insulin-dependent diabetes mellitus.

The quantitative distribution of mutans streptococci and lactobacilli in saliva of insulin-dependent diabetic children was compared with a group of healthy children and related to the metabolic control of the disease. The study group, consisting of 94 boys and girls (age 4-19) with type 1 diabetes was matched by sex and age with a non-diabetic control group. Stimulated whole saliva was collected and flow rate, buffer capacity and the levels of mutans streptococci and lactobacilli were analysed in all children. In the diabetic group, total salivary proteins and glucose content of saliva were determined. Data on caries experience were recorded from the dental cards of all children. There were no difference in the distribution or number of mutans streptococci between the groups, but significantly (p less than 0.05) lower levels of lactobacilli were found among the diabetic children. The number of lactobacilli was positively correlated (p less than 0.05) to glucose concentration in saliva. There was no difference in the prevalence of caries between the groups. The present findings suggest that the dietary treatment of young insulin dependent diabetics gives rise to a reduced number of lactobacilli in saliva but does not affect the mutans streptococci.

Adolescent↗
PubMed1995

Susceptibility of poultry lactobacilli to ionophore antibiotics.

The susceptibility of four poultry Lactobacillus strains to monensin, narasin, lasalocid, salinomycin and maduramicin was investigated using two different systems of lactobacilli cultivation. In the MRS broth (Oxoid) with glucose, the growth of lactobacilli was inhibited at ionophore concentrations as low as 0.4-5 microgram/ml. On the other hand, the growth of lactobacilli in the mixture of a commercial concentrate with water (1:2) was not influenced by ionophores at 100 micrograms/g. It follows from these results that lactobacilli are much more resistant to ionophores in their natural environment than in laboratory cultures on glucose. It was concluded that: probiotic lactobacilli can be added to ionophore-containing concentrates; antibiotic susceptibility data obtained in liquid cultures with glucose are misleading.

Animals↗