The scientific basis for probiotic strains of Lactobacillus

A pilot study evaluating the safety of vaginal administration of a multi-particulate pellet formulation

AIM

Quantitative evaluation of the effect caused by vaginal administration of gelatin capsules loaded with starch pellets and lyophilized powder, respectively, on vaginal pH and microflora.

METHOD

Administration of gelatin capsules loaded with fast-disintegrating starch pellets (group P) or lyophilized lactose/skimmed milk (group L) was compared to no intervention (group C) in a 3-way randomized, double-blinded, parallel study with 18 volunteers. Follow-up visits were at day 6 (immediately after administration), day 14 (pill stop), day 22 (after withdrawal bleeding) and day 35 (midcycle). Vaginal pH was measured and swabs were taken for Gram staining and culture to assess the presence of hydrogen peroxide-producing lactobacilli. Colposcopy was performed to assess the occurrence of adverse effects on the vaginal and ectocervical mucosa.

RESULTS

No severe adverse events occurred. For all women, vaginal pH and Gram stain were normal from screening until pill stop. Although immediately after withdrawal bleeding, 8 out of 18 women had an elevated pH, a disturbed microflora or lacked hydrogen peroxide-producing lactobacilli, all women had hydrogen peroxide-producing lactobacilli and a normal vaginal pH at midcycle, and all but two had a normal Gram stain.

CONCLUSION

No major differences could be observed between the groups, whereby all changes in pH and microflora could be ascribed to withdrawal bleeding, indicating that gelatin capsules, starch pellets and lyophilized powder are acceptable carrier materials for the vaginal delivery of probiotic strains.

Preventive effects of hyaluronic acid on Escherichia coli-induced urinary tract infection in rat

OBJECTIVES

To investigate the effects of hyaluronic acid (HA) in rat with Escherichia coli-induced urinary tract infection and duration of its effect. HA is a component of the glycosaminoglycan layer, and is known to interfere with the attachment of E. coli to the urothelium.

METHODS

The rats were divided into various groups. The E. coli-only group in which phosphate-buffered saline was instilled before E. coli (fimH+, sfa+, papA+) inoculation; HA-1, HA-3, HA-5, and HA-7 groups in which HA (0.5 mL, 0.5%) was instilled 1, 3, 5, 7 days before E. coli inoculation, respectively. To assess the symptomatic changes, we examined the voiding interval (VI) of E. coli-only group and HA-1 group before and after E. coli inoculation. Atomic force microscopy was performed to investigate the change in the urothelium before and after HA treatment.

RESULTS

Bacterial growth rate in the bladder was significantly higher in the E. coli-only group (84.6%) than in the HA-1 (20.0%), HA-3 (23.5%), and HA-5 groups (7.7%) (P <.05). The VI in E. coli-only group decreased from the first to third day after the induction of cystitis. The VI in E. coli-only group was significantly shorter than in HA-1 group (P <.05). No pathological evidence of acute inflammation was observed in the bladder and kidney of culture-negative HA groups. Atomic force microscopy showed HA coating on the urothelium.

CONCLUSIONS

This study shows that HA has an effect on the protection mechanism against the invasion of E. coli and that its effect duration is about seven days.

Vaginal lactic acid bacteria in healthy and ill bitches and evaluation of in vitro probiotic activity of selected isolates

The concentrations of lactic acid bacteria (LAB) in 42 vaginal samples from healthy and ill bitches were determined. Eight isolates belonging to the genera Lactobacillus and Enterococcus were selected and identified and their in vitro antimicrobial activity against canine pathogens and their ability to adhere to canine vaginal epithelial cells were determined. There was no correlation between the concentrations of vaginal LAB and clinical status, body temperature, vaginal pH, or age. Although the animals were either well or suffering from various illnesses, LAB were found in almost every sample, and the selected isolates showed promising probiotic-related features. These findings are significant for the design of strategies for the modulation of vaginal microbiota by vaginal LAB isolates.

Lactobacillus rhamnosus L60, a potential probiotic isolated from the human vagina

The vagina has been increasingly viewed as an "ecosystem" whose normal microflora help protect it from invading pathogens, including those that cause urinary tract infections and sexually transmitted diseases. We tested new strains of lactobacilli as potential probiotics for maintenance of urogenital tract health, as well as prevention and therapy of urogenital infections. A strain of lactobacilli isolated from the vagina of nonpregnant, healthy, premenopausal women was identified as Lactobacillus rhamnosus L60 by 16S rDNA sequence homology. L60 was evaluated for antimicrobial activity, in vitro antibiotic resistance, autoaggregation, surface hydrophobicity, co-aggregation with other bacterial species, hydrogen peroxide (H(2)O(2)) production, and bacterial adherence. It displayed a wide spectrum of antimicrobial activity against urogenital pathogens, and resistance to antibiotics commonly prescribed for infections caused by these pathogens. L60 produced H(2)O(2), adhered to vaginal epithelial cells, co-aggregated with Escherichia coli and Candida albicans, and displayed self-aggregation. In view of these characteristics, L60 is considered a potential probiotic, and will be further evaluated for preventive and therapeutic application locally in the vaginal tract.

Identification of lactobacilli by pheS and rpoA gene sequence analyses

The aim of this study was to evaluate the use of the phenylalanyl-tRNA synthase alpha subunit (pheS) and the RNA polymerase alpha subunit (rpoA) partial gene sequences for species identification of members of the genus Lactobacillus. Two hundred and one strains representing the 98 species and 17 subspecies were examined. The pheS gene sequence analysis provided an interspecies gap, which in most cases exceeded 10 % divergence, and an intraspecies variation of up to 3 %. The rpoA gene sequences revealed a somewhat lower resolution, with an interspecies gap normally exceeding 5 % and an intraspecies variation of up to 2 %. The combined use of pheS and rpoA gene sequences offers a reliable identification system for nearly all species of the genus Lactobacillus. The pheS and rpoA gene sequences provide a powerful tool for the detection of potential novel Lactobacillus species and synonymous taxa. In conclusion, the pheS and rpoA gene sequences can be used as alternative genomic markers to 16S rRNA gene sequences and have a higher discriminatory power for reliable identification of species of the genus Lactobacillus.

Obtaining of a symbiotic product based on lactic bacteria, pollen and honey

This study presents the evolution of a Lactobacillus plantarum 2s strain and of a Lactobacillus acidophilus 1a strain on media containing pollen and honey. The following parameters were determined: CFU value, lactic acid production, sugar consumption and presentation of the final product. The researches were performed during 72 h, in tightly closed recipients, at a temperature of 37 degrees C, containing various quantities of milled or non-milled pollen (P1: 20 g non-milled pollen, 3 g honey, 5 mL distilled water; P2: 20 g milled pollen, 3 g honey, 5 mL distilled water; P3: 20% non-milled pollen, 3% honey; P4: 20% milled pollen, 3% honey). The media were very well homogenized before inoculation. The inoculation was made only after the medium gained a homogenous consistency. The inoculum consists of a 48 h culture of Lactobacillus plantarum 2s and Lactobacillus acidophilus, on LE medium, in equal proportions. The testing of the nutritive value of the symbiotic product was made on wistar rats, males and females, divided into lots of 10 animals each. The animals were administered symbiotic product every day, in their food, in intakes of 2 mg kg(-1) (lot I), 20 mg kg(-1) (lot II) and 200 mg kg(-1) (lot III), compared to a control. During the 4 weeks of the experiment, no lethality cases were recorded in any of lots, or in control. The animals involved in the experiment were examined daily and did not present changes of appetite, of behavior or clinical signs of disease.

Genomic and genetic characterization of the bile stress response of probiotic Lactobacillus reuteri ATCC 55730

Probiotic bacteria encounter various stresses after ingestion by the host, including exposure to the low pH in the stomach and bile in the small intestine. The probiotic microorganism Lactobacillus reuteri ATCC 55730 has previously been shown to survive in the human small intestine. To address how L. reuteri can resist bile stress, we performed microarray experiments to determine gene expression changes that occur when the organism is exposed to physiological concentrations of bile. A wide variety of genes that displayed differential expression in the presence of bile indicated that the cells were dealing with several types of stress, including cell envelope stress, protein denaturation, and DNA damage. Mutations in three genes were found to decrease the strain's ability to survive bile exposure: lr1864, a Clp chaperone; lr0085, a gene of unknown function; and lr1516, a putative esterase. Mutations in two genes that form an operon, lr1584 (a multidrug resistance transporter in the major facilitator superfamily) and lr1582 (unknown function), were found to impair the strain's ability to restart growth in the presence of bile. This study provides insight into the possible mechanisms that L. reuteri ATCC 55730 may use to survive and grow in the presence of bile in the small intestine.

Subtractive screening for probiotic properties of lactobacillus species from the human gastrointestinal tract in the search for new probiotics

In the search for new probiotics, 61 Lactobacillus spp. isolates, belonging to 12 species and isolated as dominant lactic acid bacteria from the feces of healthy humans, were subjected to a subtractive system of in vitro analyses, which included desirable and undesirable traits. Twenty-four isolates were able to grow in 2% bovine bile, of which 13 grew in acidified broth at pH 3.5 in acidified cysteine-containing MRS broth. Intrinsic resistance to certain antimicrobial agents (cefoxitin, metronidazole, vancomycin) was observed in most isolates, but atypical resistances to erythromycin, clindamycin, or tetracycline were also found in 5 strains. Undesirable traits such as alpha-chymotrypsin or N-acetyl-beta-glucosaminidase activities were not detected, but low beta-glucuronidase and moderate beta-glucosidase activities were recorded in 2 strains. Two Lactobacillus gasseri and 2 Lactobacillus paracasei selected strains inhibited several intestinal pathogens in an agar spot test, including strains of Escherichia coli, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. They also adhered to human Caco-2 and HT-29 epithelial cells in a manner comparable to Lactobacillus rhamnosus strain GG, and were unable to degrade pig gastric mucin in a plate assay. Together, these results suggest these 4 strains to be good probiotic candidates, concluding that the subtractive screening devised in this work could be a valuable tool in large-scale surveys for probiotics.

In vitro activity of potential probiotic Lactobacillus murinus isolated from the dog

AIMS

The aim of this study was to isolate and identify Lactobacillus spp. isolates from faeces of a healthy dog, and to characterize their potential as probiotics in order to evaluate their possible use as probiotics for dogs.

METHODS AND RESULTS

An in vitro approach was used to characterize the isolates as potential probiotics including the evaluation of pH and bile salts tolerance, production of antimicrobial substances, biofilm formation on glass and polystyrene surfaces, aggregation ability and adhesion to canine intestinal mucus. The isolates survived to different pH and bile salts conditions, inhibited the in vitro growth of Escherichia coli and Clostridium perfringens, and adhered to glass and intestinal mucus.

CONCLUSIONS

The properties shown by these isolates may indicate that they could colonize and persist in the gastrointestinal tract and induce beneficial effects to the host.

SIGNIFICANCE AND IMPACT OF STUDY

The evaluation of native canine isolates and future experimental feeding assays may be useful tools to develop probiotics to improve animal health and reduce the risk of gastrointestinal disorders.

NATURAL ANTIMICROBIALS AND THEIR ROLE IN VAGINAL HEALTH: A SHORT REVIEW

Lactobacillus species maintain the vaginal ecosystem in a healthy condition by production of antimicrobial substances. Depletion of lactobacilli in the vagina results in bacterial vaginosis (BV), where the normal flora is replaced by several bacterial pathogens, usually Gardnerella vaginalis and obligate anaerobes. BV may cause complications such as premature labor, low birth weight and increased risk of HIV acquisition. The currently recommended antibiotic treatments for BV are not always effective and often lead to reoccurrence of the infection. In many cases, this is due to the antibiotic-resistant forms of the pathogens. Therefore, there is an interest in the development of treatments using antimicrobials derived primarily from Lactobacillus spp., such as ribosomally produced antimicrobial peptides (bacteriocins) and lactic acid. These substances effectively inhibit pathogenic bacteria, are safe and do not pose any threat to healthy vaginal Lactobacillus spp. It may be possible to find an effective treatment against BV while reducing the infection's reoccurrence and the treatment-related complications through hurdle technology. This would be achieved by combining antimicrobials produced by Lactobacillus spp. with different natural antimicrobials obtained from plants or other non-pathogenic organisms.

Proteomic investigation of the aggregation phenomenon in Lactobacillus crispatus

Aggregation process affects the ability of Lactobacillus crispatus, a probiotic, to survive into the gastro-intestinal environment and to adhere to the intestinal mucosa. To elucidate mechanisms underlying this process, a comparative proteomic study was carried out on a wild type strain M247 and its spontaneous isogenic mutant Mu5, which had lost the aggregative phenotype. Results highlighted an overall lower amount of enzymes involved in carbohydrate transport and metabolism in strain M247 compared to strain Mu5, suggesting a reduction in the general growth rate, probably caused by nutrient limitation in cell aggregates, coherently with the phenotypic traits of the strains. Moreover, the up-regulation of a putative elongation factor Tu in the wild type M247 strain could suggest a role of this particular protein in the adhesion mechanism of L. crispatus.

Vaginal lactic acid bacteria in the mare: evaluation of the probiotic potential of native Lactobacillus spp. and Enterococcus spp. strains

Lactic acid bacteria (LAB) are important members of the human vaginal microbiota and their presence is considered beneficial. However, little is known about native vaginal bacteria in other animal species such as the horse. The aim of this work was to quantify the vaginal lactic acid bacteria and lactobacilli of mares and to establish if selected equine vaginal lactic acid bacteria, particularly Lactobacillus and Enterococcus spp. strains, could exhibit potential as probiotics. The vaginal lactic acid bacteria and lactobacilli of 26 mares were quantified by plate counts. Five strains (three Lactobacillus spp. and two Enterococcus spp.) were characterised and adhesion to vaginal epithelial cells, antimicrobial activity and ability to form biofilms were evaluated. Lactic acid bacteria were recovered from the 26 samples and lactobacilli counts were detected in 18 out of 26 mares (69%). Probiotic properties tested in this study varied among the isolates and showed promising features for their use as equine probiotics.

Isolation of lactic acid bacteria from Malaysian foods and assessment of the isolates for industrial potential

Two traditional fermented food 'tapai' (fermented tapioca) and 'tempoyak' (fermented durian flesh), chilli puree and fresh goat's milk were used as sources for the isolation of lactic acid bacteria (LAB). A total of 126 isolates were obtained and by sequential screening for catalase activity and Gram-staining, 55 were determined to be LAB out of which 16 were established to be homofermentative by the gel plug test. Seven isolates were identified by use of the API 50CHL kit and two lactobacilli strains and one lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The lactobacilli strains, both isolated from 'tapai', produced higher amounts of cells and lactic acid from glucose as compared to the lactococci strain isolated from fresh goat's milk.

Influence of Camembert consumption on the composition and metabolism of intestinal microbiota: a study in human microbiota-associated rats

The objective of the present study was to evaluate the consequence of Camembert consumption on the composition and metabolism of human intestinal microbiota. Camembert cheese was compared with milk fermented by yoghurt starters andLactobacillus caseias a probiotic reference. The experimental model was the human microbiota-associated (HM) rat. HM rats were fed a basal diet (HMB group), a diet containing Camembert made from pasteurised milk (HMCp group) or a diet containing fermented milk (HMfm group). The level of micro-organisms from dairy products was measured in faeces using cultures on a specific medium and PCR–temporal temperature gradient gel electrophoresis. The metabolic characteristics of the caecal microbiota were also studied: SCFA, NH3, glycosidase and reductase activities, and bile acid degradations. The results showed that micro-organisms from cheese comprised 105–108bacteria/g faecal sample in the HMCp group.Lactobacillusspecies from fermented milk were detected in HMfm rats. Consumption of cheese and fermented milk led to similar changes in bacterial metabolism: a decrease in azoreductase activity and NH3concentration and an increase in mucolytic activities. However, specific changes were observed: in HMCp rats, the proportion of ursodeoxycholic resulting from chenodeoxycholic epimerisation was higher; in HMfm rats, α and β-galactosidases were higher than in other groups and both azoreductases and nitrate reductases were lower. The results show that, as for fermented milk, Camembert consumption did not greatly modify the microbiota profile or its major metabolic activities. Ingested micro-organisms were able to survive in part during intestinal transit. These dairy products exert a potentially beneficial influence on intestinal metabolism.

The use of probiotics in shrimp aquaculture: Table 1

Shrimp aquaculture, as well as other industries, constantly requires new techniques in order to increase production yield. Modern technologies and other sciences such as biotechnology and microbiology are important tools that could lead to a higher quality and greater quantity of products. Feeding and new practices in farming usually play an important role in aquaculture, and the addition of various additives to a balanced feed formula to achieve better growth is a common practice of many fish and shrimp feed manufacturers and farmers. Probiotics, as 'bio-friendly agents' such as lactic acid bacteria and Bacillus spp., can be introduced into the culture environment to control and compete with pathogenic bacteria as well as to promote the growth of the cultured organisms. In addition, probiotics are nonpathogenic and nontoxic microorganisms without undesirable side-effects when administered to aquatic organisms. These strains of bacteria have many other positive effects, which are described in this article.

Spatial and temporal expression of Lactobacillus plantarum genes in the gastrointestinal tracts of mice

Lactobacillus plantarum is a common inhabitant of mammalian gastrointestinal tracts, and L. plantarum strain WCFS1 is a human isolate with a known genome sequence. L. plantarum WCFS1 survives intestinal passage in an active form, and its transit time and transcriptional activities were monitored in 15 BALB/c mice at 2, 4, 6, 8, and 24 h after being fed a single intragastric dose of this organism. Enumeration of viable cells isolated from fecal material revealed that the majority of the L. plantarum inoculum transited the mouse intestine within 4 h after ingestion. Three mice were sacrificed at each time point, and total RNA was isolated from the mouse intestinal compartments (stomach through colon). Quantification of L. plantarum 16S rRNA by quantitative real-time reverse-transcription-PCR revealed that L. plantarum was present at elevated levels in the stomach and small intestine for at least 4 h following ingestion and for over 8 h in the cecum and colon. We also examined the expression of 9 L. plantarum housekeeping genes and 15 L. plantarum in vivo-inducible (ivi) genes previously identified by recombination-based in vivo expression technology to be induced in the mouse gastrointestinal tract. The relative expression levels of the ivi genes increased up to 350-fold in the mouse intestine compared to levels observed for L. plantarum WCFS1 cells grown in a rich laboratory medium. Moreover, several genes displayed intestinal compartment-specific (small intestine versus colon) activities. These results confirm that L. plantarum displays specific and differential responses at various sites along the mammalian intestine.

Pathophysiology, Diagnosis, and Management of Urinary Tract Infection in Horses

Equine urinary tract infection (UTI) most commonly occurs as a sequela to structural or functional inhibition of normal urine flow. Although it is an infrequent diagnosis in equids, the incidence of UTI in human beings is high and has inspired great investigative effort. The resultant findings with potentially broad application as well as current equine studies are reviewed here. Recent developments in the understanding of host-agent interactions and renal defense mechanisms, emerging antimicrobial resistance, and novel therapeutic alternatives to prophylactic antibiotic use are emphasized.

A pilot study evaluating the safety and effectiveness of Lactobacillus vaginal suppositories in patients with recurrent urinary tract infection

Changes in the indigenous vaginal microflora with uropathogenic bacteria can predispose women to frequently recurring bacterial cystitis. Lactobacilli used as probiotics have played an important role in preventing the colonization of pathogenic bacteria in the vagina. A prospective clinical pilot study was performed to confirm the safety and effectiveness of Lactobacillus vaginal suppositories against the recurrence of bacterial urinary tract infection (UTI). The patients enrolled in the study were instructed to administer vaginal suppositories containing the strain Lactobacillus crispatus GAI 98322. A significant reduction in the number of recurrences was noted, without any adverse complication (P=0.0007). The administration of vaginal suppositories containing L. crispatus GAI 98332 seemed to be a safe and promising treatment for the prevention of recurrent UTI.

Probiotics in marine larviculture

Owing to the problem of antibiotic resistance and subsequent reluctance of using antibiotics, the use of probiotics in larviculture is becoming increasingly popular. During the early stages of development, manipulation of the larval digestive system seems possible through the addition of probiotics either through the culture water or via the livefood. Well-studied probiotics used in human medicine and terrestrial agriculture have proved to be successful in aquaculture and therefore reduce the need for extensive biosafety trials. The selection of probiotics requires various in vitro screening experiments, which assay for the production of antagonist compounds, their growth in and attachment to fish intestinal mucus, and the production of other beneficial compounds such as vitamins, fatty acids and digestive enzymes. Further information regarding probiont suitability can be obtained from its identification, interaction with livefood and host pathogenicity. Finally, pilot-scale in vivo tests need be performed, after which a production cost-benefit analysis to determine its economic viability needs to be undertaken.

Supplementation of the diet with high-viscosity beta-glucan results in enrichment for lactobacilli in the rat cecum

BBn (BioBreeding) rats were fed casein-based diets supplemented with barley flour, oatmeal flour, cellulose, or barley beta-glucans of high [HV] or low viscosity [LV] in order to measure the prebiotic effects of these different sources of dietary fiber. The dietary impact on the composition of the cecal microbiota was determined by the generation of denaturing gradient gel electrophoresis (DGGE) profiles of PCR-amplified 16S rRNA gene sequences. The DGGE profiles produced from the cecal microbiota of rats within each dietary group were similar, but consensus profiles generated from pooled bacterial DNAs showed differences between rat groups. Animals fed HV glucans (HV-fed rats) had DGGE consensus profiles that were 30% dissimilar from those of the other rat groups. A 16S rRNA gene fragment that was more conspicuous in the profiles of HV-fed animals than in those of cellulose-fed rats had sequence identity with Lactobacillus acidophilus. Measurements of L. acidophilus rRNA abundance (DNA-RNA hybridization), the preparation of cloned 16S rRNA gene libraries, and the enumeration of Lactobacillus cells (fluorescent in situ hybridization) showed that lactobacilli formed a greater proportion of the cecal microbiota in HV-fed rats. In vitro experiments confirmed that some lactobacilli utilize oligosaccharides (degree of polymerization, 3 or 4) present in beta-glucan hydrolysates. The results of this study have relevance to the use of purified beta-glucan products as dietary supplements for human consumption.

Global analysis of carbohydrate utilization by Lactobacillus acidophilus using cDNA microarrays

The transport and catabolic machinery involved in carbohydrate utilization by Lactobacillus acidophilus was characterized genetically by using whole-genome cDNA microarrays. Global transcriptional profiles were determined for growth on glucose, fructose, sucrose, lactose, galactose, trehalose, raffinose, and fructooligosaccharides. Hybridizations were carried out by using a round-robin design, and microarray data were analyzed with a two-stage mixed model ANOVA. Differentially expressed genes were visualized by hierarchical clustering, volcano plots, and contour plots. Overall, only 63 genes (3% of the genome) showed a >4-fold induction. Specifically, transporters of the phosphoenolpyruvate:sugar transferase system were identified for uptake of glucose, fructose, sucrose, and trehalose, whereas ATP-binding cassette transporters were identified for uptake of raffinose and fructooligosaccharides. A member of the LacS subfamily of galactoside-pentose hexuronide translocators was identified for uptake of galactose and lactose. Saccharolytic enzymes likely involved in the metabolism of monosaccharides, disaccharides, and polysaccharides into substrates of glycolysis were also found, including enzymatic machinery of the Leloir pathway. The transcriptome appeared to be regulated by carbon catabolite repression. Although substrate-specific carbohydrate transporters and hydrolases were regulated at the transcriptional level, genes encoding regulatory proteins CcpA, Hpr, HprK/P, and EI were consistently highly expressed. Genes central to glycolysis were among the most highly expressed in the genome. Collectively, microarray data revealed that coordinated and regulated transcription of genes involved in sugar uptake and metabolism is based on the specific carbohydrate provided. L. acidophilus's adaptability to environmental conditions likely contributes to its competitive ability for limited carbohydrate sources available in the human gastrointestinal tract.

Antibiotic susceptibility of potentially probiotic vaginal lactobacilli

OBJECTIVE

To study the antimicrobial susceptibility of six vaginal probiotic lactobacilli.

METHODS

The disc diffusion method in Müeller Hinton, LAPTg and MRS agars by the NCCLS (National Committee for Clinical Laboratory Standards) procedure was performed. Due to the absence of a Lactobacillus reference strains, the results were compared to those of Staphylococcus aureus ATCC29213. Minimal Inhibitory Concentration (MIC) with 21 different antibiotics in LAPTg agar and broth was also determined.

RESULTS

LAPTg and MRS agars are suitable media to study antimicrobial susceptibility of lactobacilli. However, the NCCLS procedure needs to be standardized for this genus. The MICs have shown that all Lactobacillus strains grew at concentrations above 10 microg/mL of chloramphenicol, aztreonam, norfloxacin, ciprofloxacin, ceftazidime, ceftriaxone, streptomycin and kanamycin. Four lactobacilli were sensitive to 1 microg/mL vancomycin and all of them were resistant to 1000 microg/mL of metronidazole. Sensitivity to other antibiotics depended on each particular strain. Conclusions. The NCCLS method needs to be standardized in an appropriate medium to determine the antimicrobial susceptibility of Lactobacillus. Vaginal probiotic lactobacilli do not display uniform susceptibility to antibiotics. Resistance to high concentrations of metronidazole suggests that lactobacilli could be simultaneously used with a bacterial vaginosis treatment to restore the vaginal normal flora.

Preventive and therapeutic administration of an indigenous Lactobacillus sp. strain against Proteus mirabilis ascending urinary tract infection in a mouse model

Probiotics are increasingly being considered as non-pharmaceutical and safe potential alternatives for the treatment and prevention of a variety of pathologies including urinary tract infections. These are the most common infections in medical practice and are frequently treated with antibiotics, which have generated an intense selective pressure over bacterial populations. Proteus mirabilis is a common cause of urinary tract infections in catheterised patients and people with abnormalities of the urinary tract. In this work we isolated, identified and characterised an indigenous Lactobacillus murinus strain (LbO2) from the vaginal tract of a female mouse. In vitro characterisation of LbO2 included acid and bile salts tolerance, growth in urine, adherence to uroepithelial cells and in vitro antimicrobial activity. The selected strain showed interesting properties, suitable for its use as a probiotic. The ability of LbO2 to prevent and even treat ascending P. mirabilis urinary tract infection was assessed using an experimental model in the mouse. Kidney and bladder P. mirabilis counts were significantly lower in mice preventively treated with the probiotic than in non-treated mice. When LbO2 was used for therapeutic treatment, bladder counts of treated mice were significantly lower although no significant differences were detected in P. mirabilis kidney colonisation of treated and non-treated animals. These results are encouraging and prompt further research related to probiotic strains and the basis of their effects for their use in human and animal health.

Biodiversity-based identification and functional characterization of the mannose-specific adhesin of Lactobacillus plantarum

Lactobacillus plantarum is a frequently encountered inhabitant of the human intestinal tract, and some strains are marketed as probiotics. Their ability to adhere to mannose residues is a potentially interesting characteristic with regard to proposed probiotic features such as colonization of the intestinal surface and competitive exclusion of pathogens. In this study, the variable capacity of 14 L. plantarum strains to agglutinate Saccharomyces cerevisiae in a mannose-specific manner was determined and subsequently correlated with an L. plantarum WCFS1-based genome-wide genotype database. This led to the identification of four candidate mannose adhesin-encoding genes. Two genes primarily predicted to code for sortase-dependent cell surface proteins displayed a complete gene-trait match. Their involvement in mannose adhesion was corroborated by the finding that a sortase (srtA) mutant of L. plantarum WCFS1 lost the capacity to agglutinate S. cerevisiae. The postulated role of these two candidate genes was investigated by gene-specific deletion and overexpression in L. plantarum WCFS1. Subsequent evaluation of the mannose adhesion capacity of the resulting mutant strains showed that inactivation of one candidate gene (lp_0373) did not affect mannose adhesion properties. In contrast, deletion of the other gene (lp_1229) resulted in a complete loss of yeast agglutination ability, while its overexpression quantitatively enhanced this phenotype. Therefore, this gene was designated to encode the mannose-specific adhesin (Msa; gene name, msa) of L. plantarum. Domain homology analysis of the predicted 1,000-residue Msa protein identified known carbohydrate-binding domains, further supporting its role as a mannose adhesin that is likely to be involved in the interaction of L. plantarum with its host in the intestinal tract.

Nutritional Support for Neonatal Foals

In recent years, equine neonatal medicine has made significant advances. The importance of nutritional support for the sick neonatal foal has been recognized, and methods of providing that sup-port have been developed. Today, the clinician has many options when designing a nutritional plan for the neonatal foal. When the foal's gut permits, enteral diets are an inexpensive source of nutrients. Under conditions where the gut requires rest, methods for delivering nutrients by the parenteral route have also been developed. In this article, the nutrition of the normal and sick foal is described. Guidelines for designing a nutritional plan are also reviewed.

The probiotic approach: an alternative treatment option in urology

OBJECTIVE

The prophylactic and therapeutic use of probiotic microorganisms is a wide and still controversial field. The review paper is aimed to summarize recent findings on the health-benefiting effects of probiotics in urological diseases. The use of certain beneficial strains against urogenital infections, bladder cancer recurrence and renal stone formation is discussed.

METHODS

Literature search of PubMed documented publications and abstracts from meetings.

RESULTS

Various clinical trials have now been performed which substantiate the beneficial effects of the probiotic strains L. rhamnosus GR-1, L. fermentum RC-14 and L. crispatus CTV-05 against urogenital infections, such as urinary tract infections and bacterial vaginosis. The potential of L. casei Shirota to reduce the recurrence rate of bladder cancer is one of the most intriguing examples for the use of probiotics in medical practice. The use of O. formigenes in the prevention of calcium oxalate stone disease was only recently suggested and needs to be further investigated.

CONCLUSION

Clinical trials increasingly provide a profound scientific basis for the use of probiotics in medicinal practice including urology. Efforts to make probiotic products available which are validated according to the guidelines recommended by the WHO and FAO and produced according to Good Manufacturing Practice will contribute to the acceptance of probiotic therapy by both the physicians and the patients.

Growth of various intestinal bacteria on alternansucrase-derived oligosaccharides

AIMS

To determine whether alternansucrase (ASR)-derived oligosaccharides can support the in vitro growth of various intestinal bacteria.

METHODS AND RESULTS

Growth was assessed from each culture after incubation in a medium containing ASR-derived oligosaccharide as sole carbohydrate source. Most of the Bifidobacterium spp. tested showed growth on all five of the oligosaccharides tested while the Lactobacillus spp., Bacteroides thetaiotaomicron, coliforms and pathogenic bacteria displayed no or little growth.

CONCLUSIONS

The ASR-derived oligosaccharides were selectively utilized by many of the Bifidobacterium spp. tested but did not support significant growth of the Lactobacillus spp., Bact. thetaiotaomicron, coliforms and pathogenic bacteria tested.

SIGNIFICANCE AND IMPACT OF THE STUDY

Alternansucrase-derived oligosaccharides are a potential source of new prebiotics.

Adherence and colonization properties of Lactobacillus rhamnosus TB1, a broiler chicken isolate

AIMS

Selected lactic acid bacteria (LAB) isolated from intestinal tract of chicken have been studied in order to investigate their ability to adhere in vitro to Basement Membrane Matrigel (BMM). A selected strain showing a good adherence in BMM test was used for in vivo colonization assays.

METHODS AND RESULTS

In vitro assessment of adhesion of broiler chicken isolates was performed using BMM assay. Among LAB strains tested, Lactobacillus rhamnosus TB1 showed a good adherence that was comparable to the one of an Escherichia coli EPEC strain used as positive control. For in vivo colonization assays this strain was fluorescently stained with the carboxyfluorescein diacetate succinimidyl ester (cFDA-SE) thus allowing its detection in different layers of intestinal tract after inoculation in broiler chicken. Further, stained L. rhamnosus were found with a highest value in rectum, jejunum and ileum both 3 and 24 h after administration.

CONCLUSIONS

BMM assay is a quick method to test in vitro adhesion properties of bacterial strains and cFDA-SE-stained bacteria may be considered as an alternative method to test in vivo adhesion and colonization properties.

SIGNIFICANCE AND IMPACT OF THE STUDY

Lactobacillus rhamnosus TB1 was therefore showed to be able to adhere strongly in vitro to BMM and in vivo to intestinal epithelial cells of chicken and may be considered as a potential probiotic for chicken.

Lactobacillus reuteri β-galactosidase activity and low milk acidification ability

β-galactosidase activity was studied as a possible cause of the low milk acidification ability observed in Lactobacillus reuteri NRRL 14171. Enzymatic activity was determined in MRS broth supplemented with either glucose or lactose and milk at the middle and final stage of the exponential phase, as well as at the stationary phase. Results were compared with β-galactosidase activity in Lactobacillus casei NRRL-B1922, a strain that shows the milk acidification ability. The effects of the types of carbon and nitrogen sources were established by comparison of growth parameters (higher maximum cell concentration and specific growth rate) in broth culture and skim milk supplemented with 2% glucose or 1% casein peptone. In milk, L. reuteri showed higher β-galactosidase activity in all growth phases compared with L. casei. Greater cell concentration maxima, specific growth rates, and acidification abilities were observed in L. reuteri when it was cultured in milk supplemented with 1% casein peptone compared with non-supplemented milk cultures. Results suggest that the poor milk acidification ability observed in L. reuteri may be more related to a weak proteolytic system than to deficient β-galactosidase activity.Key words: Lactobacillus reuteri, growth parameters, β-galactosidase, acidification.

Immunoenhancing effects of a new probiotic strain, Lactobacillus fermentum PL9005

The immunoenhancing effects of Lactobacillus fermentum PL9005 were assessed via mouse intragastric inoculation. The number of immunoglobulin A-positive cells in the small intestine, CD4+ T lymphocytes in the peripheral blood, and the lymphocyte proliferation response to mitogen stimulation (lipopolysaccharide) increased in mice fed L. fermentum PL9005. The lactic acid concentration also increased dose dependently in the small intestine of mice fed L. fermentum PL9005. No differences were found in body weight, food intake, and clinical signs between mice fed L. fermentum PL9005 and the control group. Results indicated that L. fermentum PL9005 is a probiotic with immunoenhancing properties.

The Shiga toxin-producing Escherichia coli, their ruminant hosts, and potential on-farm interventions: a review

The emergence of Shiga toxin-producing Escherichia coli serotype O157:H7 as a major human pathogen over the last 2 decades has focused attention on this organism’s ruminant hosts. Despite implementation of conventional control methods, people continue to become seriously ill from contaminated meat or other food products, manure-contaminated drinking and recreational water, and direct contact with ruminants. E. coli O157:H7 can cause life-threatening disease, and is a particular threat to children, through acute and chronic kidney damage. Compared with other food-borne bacteria, E. coli O157:H7 has a remarkably low infectious dose and is environmentally robust. Cattle are largely unaffected by this organism and have been identified as the major source of E. coli O157:H7 entering the human food chain. Other Shiga toxin-producing E. coli can be pathogenic to humans and there is increasing evidence that their significance has been underestimated. Governments around the world have acted to tighten food safety regulations, and to investigate animal sources and on-farm control of this and related organisms. Potential intervention strategies on-farm include: feed and water hygiene, altered feeding regimes, specific E. coli vaccines, antibacterials, antibiotics, probiotics, and biological agents or products such as bacteriophages, bacteriocins, or colicins.

Probiotic bacteria stimulate virus-specific neutralizing antibodies following a booster polio vaccination

BACKGROUND

Orally ingested probiotic bacteria may modulate the immune response and increase antibody titers against enteric infections by bacteria or viruses. Even though positive effects of probiotics on respiratory tract infections have been reported, overall only few studies have examined effects on virus infections concerning organs other than the gastrointestinal tract.

AIM OF THE STUDY

It was the aim of the study to investigate whether and how probiotics affect the immune response to a standardized enterovirus challenge (polio) and infections not limited to the gastrointestinal tract in healthy adults.

METHODS

In a randomized, controlled and double-blind study 64 volunteers consumed for 5 weeks chemically acidified clotted milk without bacteria or with 10(10)/serving (Lactobacillus rhamnosus ) GG or Lactobacillus acidophilus CRL431 added. In the second week subjects were vaccinated orally against polio 1, 2 and 3. Polio virus neutralizing serum activity, the primary parameter, was determined by the standard neutralization test (WHO) before and three times after vaccination. Polio-specific IgA, IgG and IgM were detected by ELISAs.

RESULTS

Probiotics increased poliovirus neutralizing antibody titers (NT) and affected the formation of poliovirus-specific IgA and IgG in serum. The maximum increase after immunization was about 2, 2.2, or 4-fold higher, respectively, for NT, IgG or, IgA, in volunteers consuming probiotics instead of placebo. No consistent difference was noted between bacterial strains.

CONCLUSIONS

Probiotics induce an immunologic response that may provide enhanced systemic protection of cells from virus infections by increasing production of virus neutralizing antibodies.

Fermentation of a milk-soymilk and Lycium chinense Miller mixture using a new isolate of Lactobacillus paracasei subsp. paracasei NTU101 and Bifidobacterium longum

A milk-soymilk mixture was fermented using Lactobacillus paracasei subsp. paracasei NTU101 and Bifidobacterium longum BCRC11847 at different inoculum ratios (1:1, 1:2, 1:5, 2:1, and 5:1). When the inoculum ratio was 1:2, the cell numbers of both strains were balanced after 12 h of cultivation. The pH and titratable acidity were very similar at the various inoculum ratios of cultivation. The milk-soymilk mixture was supplemented with 5, 10, 15, and 20% Lycium chinense Miller juice and fermented with Lactobacillus paracasei subsp. paracasei NTU101 and B. longum BCRC11847. Sensory evaluation results showed that supplementation with 5% Lycium chinense Miller juice improved the acceptability of the fermented milk-soymilk. The fermented beverage was stored at 4 degrees C for 14 days; variations in pH and titratable acidity were slight. The cell numbers of L. paracasei subsp. paracasei NTU101 and B. longum BCRC11847 in the fermented beverage were maintained at 1.2x10(9) CFU/ml and 6.3x10(8) CFU/ml, respectively, after 14 days of storage.

Effect of Ampicillin on the kinetics of colonization of Streptococcus pneumoniae and Lactobacillus fermentum in the respiratory tract of mice

Ampicillin was selected to further study the effect of this antibiotic on the colonization capability of S. pneumoniae and L. fermentum intranasally inoculated in a mice experimental model. The sensitivity of S. pneumoniae and L. fermentum to antibiotics was evaluated by different "in vitro" techniques. The results showed that both microorganisms have a typical pattern of sensitivity to antibiotics in these assays. The "in vivo" experiments showed that the treatment with Ampicillin increased the number of lactobacilli and neumococci in the groups of mice treated only with one of the microorganisms. In those mice treated with Lactobacillus, challenged later with neumococci and treated with Ampicillin, the pathogen in lung decreased on the 4th day, disappearing completely after on. The histological studies showed that the antibiotic treatment decreased the inflammatory response produced by the pathogen at the lung and trachea levels.

Specific response of a novel and abundant Lactobacillus amylovorus-like phylotype to dietary prebiotics in the guts of weaning piglets

Using 16S rRNA gene-based approaches, we analyzed the responses of ileal and colonic bacterial communities of weaning piglets to dietary addition of four fermentable carbohydrates (inulin, lactulose, wheat starch, and sugar beet pulp). An enriched diet and a control diet lacking these fermentable carbohydrates were fed to piglets for 4 days (n = 48), and 10 days (n = 48), and the lumen-associated microbiota were compared using denaturing gradient gel electrophoresis (DGGE) analysis of amplified 16S rRNA genes. Bacterial diversities in the ileal and colonic samples were measured by assessing the number of DGGE bands and the Shannon index of diversity. A higher number of DGGE bands in the colon (24.2 +/- 5.5) than in the ileum (9.7 +/- 4.2) was observed in all samples. In addition, significantly higher diversity, as measured by DGGE fingerprint analysis, was detected in the colonic microbial community of weaning piglets fed the fermentable-carbohydrate-enriched diet for 10 days than in the control. Selected samples from the ileal and colonic lumens were also investigated using fluorescent in situ hybridization (FISH) and cloning and sequencing of the 16S rRNA gene. This revealed a prevalence of Lactobacillus reuteri in the ileum and Lactobacillus amylovorus-like populations in the ileum and the colon in the piglets fed with fermentable carbohydrates. Newly developed oligonucleotide probes targeting these phylotypes allowed their rapid detection and quantification in the ileum and colon by FISH. The results indicate that addition of fermentable carbohydrates supports the growth of specific lactobacilli in the ilea and colons of weaning piglets.