Manual vs. interactive power toothbrush on plaque removal and salivary Streptococcus mutans and Lactobacillus casei levels : Single-center, examiner-blinded, randomized clinical trial in orthodontic patients

INTRODUCTION

The purpose of this study was to compare efficacy of a manual and an interactive power toothbrush in orthodontic patients by assessing periodontal indexes and bacterial content of saliva samples.

METHODS

Forty patients (20 females, 20 males; age range 12-18 years) with fixed orthodontic appliances were included in the study. The patients were randomly divided into two groups in a 1:1 ratio using sealed envelopes: group 1: manual toothbrush (Oral‑B Ortho Brush, Procter&Gamble Company, Dublin, Ireland), group 2: interactive power toothbrush (Oral‑B Genius 8900, Procter&Gamble Company, Marktheidenfeld, Germany). All participants were given the same toothpaste (Colgate Triple Action, Colgate-Palmolive, New York, NY, USA). The brushing procedure for each patient was described in detail, both orally and visually, utilizing a video demonstration. Plaque and bleeding index scores were recorded for both the lower and upper arches at the beginning of the study (T0) and at weeks 6 (T1) and 12 (T2). In addition, the numbers of Streptococcus (S.) mutans, Lactobacillus (L.) casei, and Porphyromonas (P.) gingivalis bacteria were determined using a real-time polymerase chain reaction (PCR) analysis in saliva samples collected at T0, T1, and T2 times. Mann-Whitney U test and Student's t test were used to compare data between the groups, and one-way analysis of variance (ANOVA) and Friedman tests were used to compare data from different time intervals for each group.

RESULTS

Plaque index values were greater in group 1 at T1 and T2, although there was no difference between the groups at T0. The gingival index scores of both groups were similar at T0, T1, and T2. While group 2 had a larger number of salivary S. mutans at T0 and T2, there was no significant difference between the groups at T1. At all three time points, there was no significant difference in salivary L. casei levels between the groups.

CONCLUSIONS

Although the interactive power toothbrush was more effective at removing plaque than the manual toothbrush, the results of the gingival index did not reflect the plaque scores. The number of certain salivary bacteria and brush type did not appear to have a clear relationship.

Screening and Identification of Probiotic Lactobacilli from the Infant Gut Microbiota to Alleviate Lead Toxicity

Lead (Pb2+) exposure cause a potential hazard to human health and the ecological environment; however, prevention and treatment of Pb2+ toxicity remain problems. The aim of this study is to isolate a novel probiotic lead (Pb2+)-resistant Lactobacillus strain from the infant gut microbiota and to determine whether they have the probiotic properties and investigate its preventive and therapeutic effects in the early-life Pb2+ exposure mouse model. In the present study, a total of 64 Pb2+-resistant colonies were isolated from the infant gut microbiota. Of these colonies, SYF-08, identified as Lacticaseibacillus casei, exhibited a Pb2+-binding capacity and Pb2+ tolerance. The in vivo study showed that SYF-08 treatment could effectively reduce Pb2+ levels in the blood, alleviate Pb2+ enrichment in bone and brain tissues, and recover the intestinal and brain damage in both dams and offspring. SYF-08 treatment also improved the antioxidant index in the liver and kidney tissues, while increasing the diversity of the intestinal microbiota of the offspring. The results of the in vitro and in vivo studies suggest that SYF-08, isolated from infant fecal samples, is a promising candidate probiotic against Pb2+ toxicity.

Coconut Bio-yoghurt Phytochemical-chemical and Antimicrobial-microbial Activities

BACKGROUND AND OBJECTIVE

Coconut flour is known to be highly nutritious flour and contains high dietary fiber. The aim of this study was to make "bio-yoghurt beverage grafted with coconut flour and containing probiotic bacteria which is recommended as a functional milk product.

MATERIALS AND METHODS

Chemical, phytochemical studies and antimicrobial activity have been performed on coconut flour which was used to make the beverage. Bio-yoghurt beverages made with different ratios of coconut flour (0, 2, 4 and 6%) were chemical, microbiological and sensory tested when fresh and during storage for 15 days of cold storage.

RESULTS

Chemical composition of coconut flour showed reasonable contents of moisture, ash, fat, fatty acids, protein, crude fiber, total solids, total phenols and antioxidants. Coconut flour showed antibacterial activity against some foodborne pathogenic bacteria. The addition of coconut flour to make bio-yoghurt beverages increased its contents of total solids, protein, ash, fiber, acidity, antioxidant activity, total phenols, improved yoghurt sensory and rheological properties especially when probiotic bacteria were used. The results did not reveal any significant differences (p>0.05), between the bacterial counts of yoghurt starter culture, Lactobacillus rhamnosus, Lactobacillus casei in yoghurt control (without coconut) and bio-yoghurt treatments (with coconut), during cold storage. Moulds and yeasts were not detected in all bio-yoghurt treatments; meanwhile they appeared in yoghurt control after 15 days indicating coconut antifungal activity and subsequently a period of time to save more for this drink. All bio-yoghurt beverages with different ratios of coconut flour were sensory accepted and showed more favorable properties, particularly for the viscosity.

CONCLUSION

A new functional dairy product of bio-yoghurt beverage contain coconut flour high fiber content was prepared with probiotic bacteria and showed good chemical, microbiological and sensory/rheological properties.

Effect of Lactobacillus casei on serum interleukins following enteropathogenic E. coli infection in experimental rabbits

In the present study we investigated the pro-inflammatory and anti-inflammatory effect of Lactobacillus casei following infection with multi-drug resistant enteropathogenic Escherichia coli infection in experimental rabbits. For this purpose, 40 adult rabbits were divided into different groups and were infected with multi-drug resistant E. coli AZ1 strain except the control groups. The rabbits were orally administered with L. casei SABA6 strain in two different ways i.e. pre-treatment and post-treatment and both were continued for 7 days. The rabbits were sacrificed sequentially at 0, 4, 7 and 10 days post infection (dpi). Serum and intestinal tissue samples were collected from each rabbit. Intestinal tissue samples were subjected to histopathological examination that showed microscopic lesions at 4 and 7 dpi among infected group. The serum samples were processed for determination of Interleukin-6 (IL-6, pro-inflammatory) and Interleukin-10 (IL-10, anti-inflammatory) using ELISA. It was found that oral administration of L. casei SABA6 reduces the eruption of intestinal epithelial cells and reduces the incidence of diarrhea. Further, L. casei SABA6 also resulted in immuno modulation by significant increase in concentration of IL-6 and IL-10 particularly at 4 and 7 dpi and protects against E. coli AZ1 infection. Altogether, it was concluded that increased IL-6 and IL-10 levels were responsible for protection against EPEC infections. The sequential sacrifice of experimental animals could be adopted for future studies to find out pathogenesis and virulence mechanism of EPEC infections along with protective efficacy of different probiotics.

The dnaJ gene as a molecular discriminator to differentiate among species and strain within the Lactobacillus casei group

Identifying Lactobacillus casei and its closely related taxa at the species and strain level using only phenotypic and genotypic (16S rDNA sequence homology analysis) techniques often yields inaccurate results. In this study, the dnaJ chaperone gene was investigated as a molecular target for inter- and intraspecies discrimination within the Lb. casei group as well as for the development of specific primers for species identification. The results showed that most of the examined strains could be clearly distinguished from closely related species based on the sequenced fragments. At the interspecies level, the dnaJ sequence similarities were 81.7%-85.5%. However, at the intraspecies level, the dnaJ sequence similarities were 96.2-100% and could be assigned to different haplotypes in Lactobacillus paracasei and Lactobacillus rhamnosus, respectively. Compared to the 16S rRNA gene, the dnaJ sequence showed greater variation at both the species and strain level. Thus, the dnaJ gene can be proposed as an alternative marker for the Lb. casei group that provides higher discriminatory power than the 16S rRNA gene. In addition, species-specific primers were developed and subsequently employed in two-plex minisequencing analysis and shown to be specific for Lb. paracasei and Lb. rhamnosus. Our data indicate that phylogenetic relationships in the Lb. casei group can be resolved using comparative sequence analysis of the dnaJ gene and that the Lb. paracasei and Lb. rhamnosus species can be simultaneously identified using a novel species-specific minisequencing assay.

Lactic acid bacteria and natural antimicrobials to improve the safety and shelf-life of minimally processed sliced apples and lamb's lettuce

Outbreaks of food-borne disease associated with the consumption of fresh and minimally processed fruits and vegetables have increased dramatically over the last few years. Traditional chemical sanitizers are unable to completely eradicate or kill the microorganisms on fresh produce. These conditions have stimulated research to alternative methods for increasing food safety. The use of protective cultures, particularly lactic acid bacteria (LAB), has been proposed for minimally processed products. However, the application of bioprotective cultures has been limited at the industrial level. From this perspective, the main aims of this study were to select LAB from minimally processed fruits and vegetables to be used as biocontrol agents and then to evaluate the effects of the selected strains, alone or in combination with natural antimicrobials (2-(E)-hexenal/hexanal, 2-(E)-hexenal/citral for apples and thyme for lamb's lettuce), on the shelf-life and safety characteristics of minimally processed apples and lamb's lettuce. The results indicated that applying the Lactobacillus plantarum strains CIT3 and V7B3 to apples and lettuce, respectively, increased both the safety and shelf-life. Moreover, combining the selected strains with natural antimicrobials produced a further increase in the shelf-life of these products without detrimental effects on the organoleptic qualities.

Effect of Aloe vera (Aloe barbadensis Miller) on survivability, extent of proteolysis and ACE inhibition of potential probiotic cultures in fermented milk

BACKGROUND

In the present investigation, the effect of Aloe vera gel powder on angiotensin-converting enzyme (ACE) inhibitory activity, extent of proteolysis during fermentation and survival of Lactobacillus casei NCDC19 during storage of fermented milk was studied.

RESULTS

Among the different cultures screened for ACE inhibitory activity, Lactobacillus casei NCDC 19 exhibited the highest ACE inhibition (approx. 40%) as well as extent of proteolysis (0.37, Abs₃₄₀). In the presence of Aloe vera (0.5% and 1% w/v) an increase in extent of proteolysis (0.460 ± 0.047 and 0.480 ± 0.027) and percent ACE inhibitory activity (44.32 ± 2.83 and 47.52 ± 1.83) was observed in comparison to control. Aloe vera powder addition also led to an increase in viable counts (>11 log cfu mL⁻¹) of L. casei NCDC 19 in fermented milk during storage for 7 days and the counts were maintained in sufficiently higher numbers.

CONCLUSION

The study suggests Aloe vera to be a good functional ingredient which can be further explored for different health attributes.

Blood contamination of used dental anesthetic cartridges

This study sought to determine the levels of blood contamination found in and/or on used dental anesthetic cartridges and to measure antibacterial effects after exposure to a local anesthetic solution. The study analyzed a total of 1000 used cartridges from an oral surgery clinic, containing 1 of 3 anesthetic types. Blood testing included visual observations (using a dissecting microscope) and chemical analyses. From each cartridge, either 0.5 ml of residual anesthetic solution or a combination of anesthetic solution plus added saline was removed. Using reagent strip dipsticks, the solutions were analyzed for minute amounts of blood. Visual examinations were scored on a positive or negative scale. In addition, 4 types of bacteria were mixed with lidocaine or phosphate buffered saline (PBS) for up to 30 days, and viable cell counts decreases were measured for the 2 solutions. A majority of the cartridges evaluated contained lidocaine, and while only 7 of the 1000 cartridges examined contained visible blood, the reagent strips detected blood in more than 76% of all cartridges. Lidocaine and PBS produced similar bacterial death rates. The authors concluded that blood contamination levels in the absence of pronounced antibacterial activity indicate that dental anesthetic cartridges could be considered a potential type of regulated medical waste.

[Influence of Lactobacillus casei on biofilm formation by enteroaggregative Escherichia coli strains isolated from irritable bowel syndrome (IBS)]

INTRODUCTION

Many pathogenic bacterial species have the ability to biofilm formation. In our study we determined the influence of Lactobacillus casei on biofilm formation by enteroaggregative Escherichia coli (EAEC) strains obtained from irritable bowel syndrome patients.

METHODS

The ability of EAEC isolates to biofilm formation was assessed in the presence of various concentrations of the probiotic L. casei strain in an a semi- quantitative microtitre plate assays under culture conditions, similar to those prevailing in the human intestine.

RESULTS

Depending on the concentrations L. casei inhibited biofilm formation of the majority (> 80%) of the EAEC strains. Concentration of 4.5 x 10(7) cfu/ml of L. casei was the most effective inhibitory dose, although a few strains (approximately 18%) formed the biofilm regardless of the presence and concentration of the probiotic L. casei strain.

CONCLUSION

The inhibitory effect of L. casei on biofilm formation at most of studied EAEC strains suggest that L. casei may reduce the risk of developing persistent intestinal infections in humans.

Viability of Lactobacillus casei strain Shirota (LcS) from feces of Thai healthy subjects regularly taking milk product containing LcS

OBJECTIVE

To demonstrate the recovery of Lactobacillus casei strain Shirota (LcS) from feces of Thai subjects who regularly took LcS containing milk product for 1 week and demonstrate the disappearance of LcS after stopped taking milk product.

MATERIAL AND METHOD

First fecal samples were collected from 20 healthy adults at 10 days after they abstained from all lactobacillus containing milk products. Second specimens taken after the subjects ingested LcS containing milk product for 7 days and third specimens at 7 days after they stopped taking LcS containing milk product. All the fecal specimens were culture for LcS using LLV-FOS culture medium and enumeration of LcS was calculated. All stool samples were also tested for the presence of LcS by using nested PCR to confirm the presence of LcS obtained from culture method.

RESULTS

Both culture and nested PCR method showed that all the stools samples obtained from subjects prior to the administration of LcS containing milk product were devoid of LcS, except for 3 specimens which showed weakly positive test for PCR. At 7 days after ingesting LcS containing milk product, all stool specimens were positive for LcS on both culture and PCR method. At 7 days after stopped taking LcS containing milk product, 1/19 specimens were positive from culture and 6/ 19 specimens were positive for PCR method.

CONCLUSION

LcS could survive in the gastrointestinal tract of Thai subjects and could be recovered from the feces after ingestion.

PCR screening and sequence analysis of iol clusters in Lactobacillus casei strains isolated from koumiss

The iol cluster (consisting of genes involved in myo-inositol utilization) was investigated in Lactobacillus casei strains isolated from koumiss. Ten strains were tested for the presence of iol cluster by PCR screening; three strains encoded this cluster. Full-sequencing procedure was conducted; the iol cluster was identical to that of L. casei BL23 (GenBank access. no. FM177140) except for an upstream transposase. The iol cluster is not a common feature for L. casei strains isolated from koumiss.

[Colonization and distribution of recombinant Lactobacillus casei with green fluorescent protein in mice intestine]

OBJECTIVE

We studied the colonization ability and the distribution of the recombinant Lactobacillus casei in mouse intestine.

METHODS

We used Green fluorescent protein (GFP) gene as reporter in constructing the recombinant plasmid pLA-GFP,which was electrotransformed into the host cells L. casei. Six-week-old female SPF BALB/c mice were orally fed with the recombinant L. casei of approximately 10(9). Groups of at least three mice per condition were killed at 1. 5 h, 3 h, 12 h, 1 d, 3 d, 5 d, 6 d, 7 d,and its duodenum, jejunum, ileum, caecum intestinal tract rinse solution was sampled separately. The recombinant bacteriain intestinal tracts were examined by plate culture count.

RESULTS

The molecular weight of the recombinant protein was about 69 kDa in the result of western blot. The GFP fusion protein on the cell surface was confirmed by fluorescence microscopy and flow cytometric analysis. A portion of the recombinant L. casei was able to adhere and colonize in different regions of murine intestinal tract, and the planting peak was appeared on day 6 postinoculation. The ratio of the seventh day to the first day of the recombinant L. casei adhered to the intestinal mucosa in the duodenum,jejunum, ileum, and caecum was 16.49%, 25.08%, 47.71%, and 41.03%, respectively.

CONCLUSION

The recombinant L. casei stably expressing GFP could colonize mouse intestine. The field planting rule was ileum > caecum > jejunum > duodenum. Our findings indicated that L. casei used as a deliver vector in oral vaccine is feasible, but the impact on intestinal immune mechanism in mice is needed more research.

A case of Lactobacillus casei bacteraemia associated with aortic dissection: is there a link?

We describe an unusual case of Lactobacillus casei bacteraemia in a heavy dairy consumer woman, with a one month history of low grade fever and admitted to our hospital for sudden onset of severe thoracic pain due to dissection of the aortic arch and ascending aorta. The patient underwent four weeks of intravenous ampicillin (2 g every 4 hours) followed by 2 weeks of oral amoxicillin (1 g every 8 hours) with resolution of fever, thoracic pain and progression of aortic disease. On the basis of the patient's symptoms, a possible penetration of L. casei in an aortic wall defect with development of aortic dissection is hypothesized.

[Screening of a Lactobacillus casei with monoamine oxidase-inhibitory activity]

OBJECTIVE

To screen for monoamine oxidase (MAO)-inhibiting lactobacillus from healthy human dejecta in an in vitro model, and to provide reference for anti-ageing study in vivo of lactobacillus in the future.

METHODS

The monoamine oxidase inhibitory model in vitro was applied to screen fermented supernatant and cell-free extracts originated from lactic acid bacteria, and two indices based on screened samples were determined, including biological dosage-effect and the effect of pre-incubated time between MAO and inhibitor on suppression rate. Meanwhile, with membrane separation technology, MAO inhibition from different molecular weight range of samples was measured. Screened strain JH-23 was investigated as target probiotic lactobacillus, identified through the sequence analysis of 16S rDNA gene and API system.

RESULTS

The MAO inhibitory rate of cell-free extracts produced by strain JH-23 reached 33.7%. After samples being vacuum freeze-dried, MAO inhibitory rate was up to 53.2% when the reactive concentration was 16 mg/mL. The inhibition was significantly enhanced with the duration of pre-incubation increased, and then the inhibitory effect became steady after 30 minutes. Crude samples were dialyzed for 48 hours, MAO inhibitory effect of dialysates was significantly increased compared with pre-dialysis. The result of bacteria identification demonstrated that strain JH-23 was ascribed to Lactobacillus casei.

CONCLUSION

A new screening model in vitro, regarding monoamine oxidase as a target enzyme, was explored in this study. This model was characterized by convenience, rapidity and high sensitivity, and it could be useful for the following anti-aging research in vivo. The cell-free extracts of Lactobacillus casei JH-23 was inhibitory to MAO, and the intracellular small-molecules played a major role in the inhibition.

Lactobacillus casei abundance is associated with profound shifts in the infant gut microbiome

Colonization of the infant gut by microorganisms over the first year of life is crucial for development of a balanced immune response. Early alterations in the gastrointestinal microbiota of neonates has been linked with subsequent development of asthma and atopy in older children. Here we describe high-resolution culture-independent analysis of stool samples from 6-month old infants fed daily supplements of Lactobacillus casei subsp. Rhamnosus (LGG) or placebo in a double-blind, randomized Trial of Infant Probiotic Supplementation (TIPS). Bacterial community composition was examined using a high-density microarray, the 16S rRNA PhyloChip, and the microbial assemblages of infants with either high or low LGG abundance were compared. Communities with high abundance of LGG exhibited promotion of phylogenetically clustered taxa including a number of other known probiotic species, and were significantly more even in their distribution of community members. Ecologically, these aspects are characteristic of communities that are more resistant to perturbation and outgrowth of pathogens. PhyloChip analysis also permitted identification of taxa negatively correlated with LGG abundance that have previously been associated with atopy, as well as those positively correlated that may prove useful alternative targets for investigation as alternative probiotic species. From these findings we hypothesize that a key mechanism for the protective effect of LGG supplementation on subsequent development of allergic disease is through promotion of a stable, even, and functionally redundant infant gastrointestinal community.

Microbiological profiles in saliva and supragingival plaque from caries-active adolescents before and after a short-term daily intake of milk supplemented with probiotic bacteria - a pilot study

PURPOSE

The aim of the present pilot study was to investigate the microbial profile in saliva and supragingival plaque samples collected from caries-active adolescents before and after a daily short-term intake of milk supplemented with the probiotic bacteria.

MATERIALS AND METHODS

The present study group consisted of 18 caries-active adolescents of both sexes who volunteered for participation giving an informed consent. The study has a randomised placebo-controlled double-blind pilot design with two parallel arms. After a 2-week run-in period, the subjects were instructed to drink 2.5 dl of milk supplemented with Lactobacillus rhamnosus LB21 (107 CFU/ml) (test) or standard control milk (placebo) once daily for a period of 2 weeks (intervention period). Samples of stimulated whole saliva and supragingival plaque were collected at baseline (after run-in) and immediately after the end of the intervention period (follow-up). The salivary levels of mutans streptococci and lactobacilli were estimated by conventional culturing on selective agar plates. The presence and level of 19 oral species associated with the caries process were determined using the checkerboard DNA-DNA hybridisation technique. Differences between the groups were assessed using the non-parametric Wilcoxon–Mann–Whitney and chi-square tests.

RESULTS

The mean caries experience was high with an average of 7.0 ± 3.8 proximal enamel lesions. The most prevalent dominating species in the plaque samples were Streptococcus mitis, Veillonella parvula and Streptococcus gordonii. The saliva samples displayed a more mixed profile, with Streptococcus mitis, Rothia dentocariosa, Lactobacillus casei and Lactobacillus curvata being frequently identified species. All of the subjects harboured mutans streptococci in their saliva, with 61% of them colonised with salivary lactobacilli. No statistically significant differences in the microbial profiles or the estimated counts between the baseline and follow-up samples, or between the two study groups, were observed.

CONCLUSIONS

The present study showed that a short-term daily intake of milk supplemented with the probiotic bacterium L. rhamnosus LB21 did not significantly affect the microbial profiles or the levels of caries-associated bacteria in saliva and supragingival plaque samples collected from caries-active adolescents.

Oral Lactobacillus species in type 2 diabetic patients living in southern Thailand

Although lactobacilli are part of normal oral, gastrointestinal and genitourinary flora, they are an uncommon cause of infections in human. Lactobacillus-associated infections have generally occurred in patients with serious underlying conditions e.g. diabetes and cancer that might favour certain microorganisms. The aim of this study was to characterize species and genotypes of lactobacilli isolated from diabetic patients and non-diabetic subjects. One hundred and five type 2 diabetic patients and 103 non-diabetic subjects were recruited in this study. A total of 170 isolates of Lactobacillus were identified using 16S rRNA gene PCR-RFLP and genotyping were performed using AP-PCR by ERIC primers. It was found that type 2 diabetic patients had a significantly higher prevalence (p = 0.008) and level of lactobacilli than non-diabetic controls (p = 0.030). The most frequently isolated Lactobacillus spp. were L. casei/paracasei and L. fermentum in both the diabetic and non-diabetic groups. Strains of L. casei/paracasei and L. fermentum from between and within individuals were genotyped, and the genotyping of Lactobacillus strains showed diversity between individuals. One up to three genotypes of these two species could be found in the same subject. Interestingly, fewer genotypes were found in the diabetic patients than in the non-diabetic subjects.

Genotypic and phenotypic characterization of Lactobacillus casei strains isolated from different ecological niches suggests frequent recombination and niche specificity

Lactobacillus casei strains are lactic acid bacteria (LAB) that colonize diverse ecological niches, and have broad commercial applications. To probe their evolution and phylogeny, 40 L. casei strains were characterized; the strains included isolates from plant materials (n=9), human gastrointestinal tracts (n=7), human blood (n=1), cheeses from different geographical locations (n=22), and one strain of unknown origin. API biochemical testing identified niche-specific carbohydrate fermentation profiles. A multilocus sequence typing (MLST) scheme was developed for L. casei. Partial sequencing of six housekeeping genes (ftsZ, metRS, mutL, nrdD, pgm and polA) revealed between 11 (nrdD) and 20 (mutL) allelic types, as well as 36 sequence types. Phylogenetic analysis of MLST data by Reticulate and split decomposition analysis indicated frequent intra-species recombination. Purifying selection was detected, and is likely to have contributed to the evolution of certain L. casei genes. Pulsed-field gel electrophoresis (PFGE) using SfiI was able to discriminate all the isolates, even those not differentiated by MLST. Phylogenetic trees reconstructed based on the MLST data using minimum evolution algorithm, and the SfiI-PFGE restriction patterns using the unweighted-pair group method with arithmetic mean (UPGMA), revealed consensus clusters of strains specific to cheese and silage. Topological discrepancies between the MLST and PFGE trees were also observed, suggesting that intragenic point mutations have accumulated at a slower rate than indels and genome rearrangements in L. casei. The L. casei population analysed in this study demonstrated both a high level of phenotypic and genotypic diversity, as well as specificity to different ecological niches.

Microbiological evaluation of elastomeric chains

OBJECTIVES

To evaluate in vitro the surface of elastomeric chains of different manufacturers to verify the presence of pathogenic microorganisms at the moment of unpacking and analyze a possible inhibitory effect of the elastomeric chain when exposed to microorganisms of the oral cavity, for example, Streptococcus mutans, Lactobacillus casei, and Candida albicans.

MATERIALS AND METHODS

Elastomeric chains from Ortho-Organizers Inc, 3M Unitek, and Dental Morelli were placed in petri plates with brain heart infusion agar medium and in sterile test tubes with brain heart infusion broth. The samples were incubated at 37 degrees C and analyzed at 24 hours, 48 hours, 3 days, and 7 days. In addition, elastomeric chains from the three manufacturers were placed in dishes, inoculated with microorganisms, incubated at 37 degrees C, and analyzed after 24 and 72 hours.

RESULTS

No microorganism growth was detected after all incubation periods. No inhibition zones were identified surrounding the elastomeric chain.

CONCLUSIONS

The results suggest that the fabrication of elastomeric chain is in accordance with biohazard concepts. However, careful manipulation is necessary to avoid colonization of pathogenic microorganisms since the composition of the elastomeric chains analyzed do not include antimicrobial agents.

Survivability of a probiotic Lactobacillus casei in the gastrointestinal tract of healthy human volunteers and its impact on the faecal microflora

AIM

The aim of this study was to measure the gastrointestinal survival of Lactobacillus casei and its impact on the gut microflora in healthy human volunteers.

METHODS AND RESULTS

Twenty healthy volunteers took part in a double-blind placebo-controlled probiotic feeding study (10 fed probiotic, 10 fed placebo). The probiotic was delivered in two 65 ml aliquots of fermented milk drink (FMD) daily for 21 days at a dose of 8.6 +/- 0.1 Log(10)Lact. casei CFU ml(-1) FMD. Faecal samples were collected before, during and after FMD or placebo consumption, and important groups of faecal bacteria enumerated by fluorescent in situ hybridization (FISH) using oligonucleotide probes targeting the 16S rRNA. The fed Lact. casei was enumerated using selective nutrient agar and colony identity confirmed by pulsed field gel electrophoresis. Seven days after ingestion of FMD, the Lact. casei was recovered from faecal samples taken from the active treatment group at 7.1 +/- 0.4 Log(10) CFU g(-1) faeces (mean +/- SD, n = 9) and numbers were maintained at this level until day 21. Lact. casei persisted in six volunteers until day 28 at 5.0 +/- 0.9 Log(10) CFU g(-1) faeces (mean +/- SD, n = 6). Numbers of faecal lactobacilli increased significantly upon FMD ingestion. In addition, the numbers of bifidobacteria were higher on days 7 and 21 than on days 0 and 28 in both FMD fed and placebo fed groups. Consumption of Lact. casei had little discernible effect on other bacterial groups enumerated.

CONCLUSIONS

Daily consumption of FMD enabled a probiotic Lact. casei strain to be maintained in the gastrointestinal tract of volunteers at a stable relatively high population level during the probiotic feeding period.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study has confirmed that this probiotic version of Lact. casei survives well within the human gastrointestinal tract.

Composition and metabolism of the intestinal microbiota in consumers and non-consumers of yogurt

The objective of the present study was to evaluate the impact of a regular consumption of yogurt on the composition and metabolism of the human intestinal microbiota. Adult subjects were selected on the basis of daily food records and divided into two groups: yogurt consumers (at least 200 g yogurt consumed per d, n 30); non-consumers (no yogurt, n 21). Their faecal microbiota was analysed using molecular methods (in situ hybridisation and PCR amplification combined with separation by denaturing gel electrophoresis) and its metabolic characteristics were assessed by measuring glycosidase, P-glucuronidase and reductase activities and profiling SCFA, neutral sterols and bile acids. The yogurt starter Lactobacillus delbrueckii ssp. bulgaricus (identity confirmed by 16S rRNA sequencing) was detected in 73% of faecal samples from fermented milk consumers v. 28% from non-consumers (P=0.003). In yogurt consumers, the level of Enterobacteriaceae was significantly lower (P=0.006) and 13-galactosidase activity was significantly increased (P=0.048). In addition, within this group, 3-galactosidase activity and the Bifidobacterium population were both positively correlated with the amount of fermented milk ingested (r 0.66, P<0.0001 and r 0.43, P=0.018, respectively). Apart from these effects, which can be considered beneficial to the host, no other major differences could be detected regarding the composition and metabolic activity of intestinal microbiota.

Survival and retention of the probiotic Lactobacillus casei LAFTI�L26 in the gastrointestinal tract of the mouse

AIMS

This study aimed to develop methods for the detection of the probiotic Lactobacillus casei LAFTI L26 (L26) from mouse faeces, and to determine the survival and retention time of L26 in the mouse gastrointestinal tract.

METHODS AND RESULTS

A selective medium, de Man Rogosa Sharpe (MRS) + bromocresol green + vancomycin (MGV), was designed for the isolation and enumeration of L26 from faecal samples of mice. PCR primers were designed to confirm the identity of L26-like colonies on MGV. These primers did not produce PCR products from related organisms that grew on MGV. Following the administration of L26 to BALB/c mice, faecal samples were collected and analysed using the designed methods. Survival studies showed viable L26 cells to be present in the faeces of mice for >48 h.

CONCLUSIONS

Our results suggest that L26 is able to survive and be retained within the digestive tract of mice for at least 48 h following oral administration.

SIGNIFICANCE AND IMPACT OF THE STUDY

MGV allows effective recovery of L26 from the background microbiota, including lactobacilli of mice. PCR was used to confirm that L26-like colonies were correctly identified as L26. Given the long retention time of L26 in the gastrointestinal tract of mice, it would appear that this probiotic strain may survive in the human gastrointestinal tract.

Stimulation of Indigenous Lactobacilli by Fermented Milk Prepared with Probiotic Bacterium, Lactobacillus delbrueckii subsp. bulgaricus Strain 2038, in the Pigs

The aim of this study was to evaluate the effect of feeding yoghurt, prepared with Lactobacillus delbrueckii subsp. bulgaricus strain 2038, on indigenous lactobacilli in the pig cecum. Three female pigs fistulated at the cecum were fed 250 g of this yoghurt that contained over 10(11) colony-forming units of L. delbrueckii subsp. bulgaricus strain 2038 with their daily meal for 2 wk. The relative abundance and the composition of cecal lactobacilli was monitored by analysis of bacterial 16S rDNA with real time PCR and amplified bacterial rDNA restriction analysis using Lactobacillus-group specific primers, respectively, for 2 wk prior to, at the end of 2 wk of and 2 wk after the administration of this yoghurt. The relative abundance of lactobacilli was significantly increased by feeding yoghurt (p<0.01), although the bacterial 16S rDNA matching L. delbrueckii subsp. bulgaricus strain 2038 was not detected by amplified bacterial rDNA restriction analysis during this study. The number of operational taxonomic units (OTUs) detected was increased with feeding of the yoghurt in all pigs. At the same time, the estimated cell number of each OTU was increased with feeding of the yoghurt. It is demonstrated that continuous consumption of the probiotic lactobacilli will stimulate the growth of some indigenous lactobacilli and alter the composition of the lactobacilli.

Perioperative synbiotic treatment to prevent postoperative infectious complications in biliary cancer surgery: a randomized controlled trial

SUMMARY BACKGROUND DATA

Use of synbiotics has been reported to benefit human health, but clinical value in surgical patients remains unclear.

OBJECTIVE

To investigate the effect of perioperative oral administration of synbiotics upon intestinal barrier function, immune responses, systemic inflammatory responses, microflora, and surgical outcome in patients undergoing high-risk hepatobiliary resection.

METHODS

Patients with biliary cancer involving the hepatic hilus (n = 101) were randomized before hepatectomy, into a group receiving postoperative enteral feeding with synbiotics (group A); or another receiving preoperative plus postoperative synbiotics (group B). Lactulose-mannitol (L/M) ratio, serum diamine oxidase (DAO) activity, natural killer (NK) cell activity, interleukin-6 (IL-6), fecal microflora, and fecal organic acid concentrations were determined before and after hepatectomy. Postoperative infectious complications were recorded.

RESULTS

Of 101 patients, 81 completed the trial. Preoperative and postoperative changes in L/M ratio and DAO activity were similar between groups. Preoperatively in group B, NK activity, and lymphocyte counts increased, while IL-6 decreased significantly (P < 0.05). Postoperative serum IL-6, white blood cell counts, and C-reactive protein in group B were significantly lower than in group A (P < 0.05). During the preoperative period, numbers of Bifidobacterium colonies cultured from and total organic acid concentrations measured in feces increased significantly in group B (P < 0.05). Postoperative concentrations of total organic acids and acetic acid in feces were significantly higher in group B than in group A (P < 0.05). Incidence of postoperative infectious complications was 30.0% (12 of 40) in group A and 12.1% (5 of 41) in group B (P < 0.05).

CONCLUSIONS

Preoperative oral administration of synbiotics can enhance immune responses, attenuate systemic postoperative inflammatory responses, and improve intestinal microbial environment. These beneficial effects likely reduce postoperative infectious complications after hepatobiliary resection for biliary tract cancer.

Survival of Lactobacillus casei in the human digestive tract after consumption of fermented milk

A human trial was carried out to assess the ileal and fecal survival of Lactobacillus casei DN-114 001 ingested in fermented milk. Survival rates were up to 51.2% in the ileum and 28.4% in the feces. The probiotic bacterium has the capacity to survive during its transit through the human gut.

Cariogenic Bacteria and Caries Risk in Elderly Japanese Aged 80 and Older with at Least 20 Teeth

OBJECTIVES

To assess caries risk and check the presence of four commonly found oral cariogenic bacteria in "8020" achievers.

DESIGN

Initial report based on Japan's newly implemented "8020" campaign, which aims to promote health and awareness in older people. Simply stated, the goal is, at 80 years, to maintain 20 teeth.

SETTING

Healthy community-dwelling elderly individuals of Okayama Prefecture, Japan.

PARTICIPANTS

One hundred sixty individuals aged 80 and older with 20 of their own natural teeth.

MEASUREMENTS

General and oral health conditions, caries risk assessment using the Cariostat method, and polymerase chain reaction (PCR) detection of four oral cariogenic bacteria.

RESULTS

The participants had an average of 24.7 teeth, of which 12.1 were sound, 12.2 were treated, and 0.4 were untreated. Based on Cariostat scores, 64.4% had low caries risk. Using PCR, Streptococcus mutans, S. sobrinus, Lactobacillus casei, and L. plantarum were detected in 51.3%, 23.1%, 40%, and 25% of the participants, respectively. S. mutans (P<.001), S. sobrinus (P=.002), L. casei (P<.001), and L. plantarum (P=.001) deoxyribonucleic acid band was detected more in participants with high caries risk scores.

CONCLUSION

Participants with low caries risk scores had low prevalence of cariogenic bacteria, 20 or more sound teeth, and fewer missing teeth. Incorporating caries risk assessment, using the Cariostat and PCR analysis, in the "8020" campaign in health systems worldwide will contribute to a better life for the aging society, initiate research interest regarding the program, and improve current health policies.

Use of polymerase chain reaction techniques and sodium dodecyl sulfate-polyacrylamide gel electrophoresis for differentiation of oral Lactobacillus species

BACKGROUND/AIMS

The genus Lactobacillus has been associated with dental caries in humans, although it is seldom speciated due to lack of simple and nonlaborious identification methods. A considerable heterogeneity among Lactobacillus species has been demonstrated. The purpose of this study was to develop simple methods combining restriction fragment length polymorphism analysis of polymerase chain reaction (PCR)-amplified 16S rRNA (16S rRNA gene PCR-RFLP) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for the identification of 13 reference strains of Lactobacillus.

METHODS

The 16S rRNA gene sequences were amplified by PCR using universal primers and digestion of PCR products with the restriction endonucleases, HpaII and HaeIII. The 16S rRNA gene PCR-RFLP is reproducible and has been proved to be useful for differentiating Lactobacillus strains to species level. Seventy-seven Lactobacillus isolates from a Thai population were used to show the applicability of the identification test.

RESULTS

PCR-RFLP alone had limitations, because the RFLP patterns of Lactobacillus casei and Lactobacillus rhamnosus and of Lactobacillus acidophilus and Lactobacillus crispatus showed similar patterns; however, these could be differentiated by SDS-PAGE. Of the 77 isolates, 38 were identified as Lactobacillus fermentum, 25 as L. rhamnosus, 5 as Lactobacillus salivarius, 5 as L. casei, 3 as L. acidophilus and 1 as Lactobacillus plantarum.

CONCLUSION

16S rRNA gene PCR-RFLP, using HpaII and HaeIII, together with SDS-PAGE protein profiles could be an alternative method for the identification of oral Lactobacillus strains to species level, and may be applicable for large-scale studies on the association of Lactobacillus to dental caries.

Oral immunoadjuvant activity of Lactobacillus casei subsp. casei in dextran-fed layer chickens

We recently reported that synbiotic Lactobacillus casei subsp. casei together with specific substrate dextran elicited an enhancement in humoral immune response against bovine serum albumin (BSA) as a model antigen in BALB/c mice. The present study was designed to evaluate the oral immunoadjuvant effects of the synbiotic in layer chickens. Using a PCR assay, L. casei subsp. casei was detected specifically in the intestinal chyme of chickens (10 d of age, Julia strain) fed ad libitum on a diet supplemented with 75 mg dextran/kg (dextran-supplemented diet, DSD) and administered orally with 10(7) colony-forming units (CFU) L. casei subsp. casei in 0.1 ml PBS with the aid of an intubation needle at 1, 2 and 3 d of age. Furthermore, oral administration of 10(7) CFU L. casei subsp. casei at 1-3 d of age significantly enhanced the production of anti-BSA antibody in DSD-fed chickens (60 d of age) administered orally with 1 mg BSA at 32 and 33 d of age and subcutaneously with 5 microg BSA at 33 d of age. In addition, among bacterial numbers tested, 10(6) CFU L. casei subsp. casei together with dextran induced an effective increase in humoral immune response to mixed inactivated vaccines against Newcastle disease and avian infectious bronchitis, and the treatment may be advantageous in protecting against these infectious diseases in chickens in actual application. These results suggest that dietary supplementation of L. casei subsp. casei with dextran leads to immunomodulation of humoral immune responses.

Effects of orally administered Lactobacillus casei DN-114 001 on the composition or activities of the dominant faecal microbiota in healthy humans

The composition and activities of the faecal microbiota in twelve healthy subjects analysed in a single open study were monitored before (1-week baseline step), during (10 d supplementation step) and after (10 d follow-up step) the ingestion of a fermented milk containing Lactobacillus casei DN-114 001. Fluorescent in situ hybridisation with group-specific DNA probes, real-time PCR using L. paracasei group-specific primers and temporal temperature gradient gel electrophoresis (TTGE) using group-specific primers were carried out, together with bacterial enzyme activity and metabolite analyses to monitor the structure and activities of the faecal microbiota. L. casei DNA was detected in the faeces of all of the subjects by TTGE after 10 d supplementation. Its quantification by real-time PCR showed a 1000-fold increase during the test step compared with initial levels. No major modification in either the dominant members of the faecal microbiota or their activities was observed during the trial. In conclusion, the short-term consumption of a milk product containing L. casei DN-114 001 was accompanied by a high, transient increase in the quantity of this strain in the faeces of all of the subjects without markedly affecting biochemical or bacteriological factors.

Clinical safety of Lactobacillus casei shirota as a probiotic in critically ill children

OBJECTIVE

Diarrhea is frequently observed among critically ill children (CIC) admitted for intensive care. There is increasing evidence that probiotics decrease the incidence of acute infectious and nosocomial and antibiotic induced diarrhea amongst children hospitalized in nonintensive care settings. Despite theoretic advantages for the use of probiotics in CIC, safety has remained a concern in this vulnerable group. The objective of this study was to establish clinical safety (invasive infection/colonization) of Lactobacillus casei shirota (LCS) used as a probiotic in CIC.

METHODS

Prospective, descriptive pilot study on children admitted to a pediatric intensive care unit. Data regarding safety were collected on the initial recruits to a randomized controlled trial aimed to study the effects of LCS on stool frequency and consistency in CIC. Safety was assessed by bacteriologic surveillance for LCS in surface swabs and endotracheal aspirates (colonization) as well as blood, urine, and sterile body fluid cultures (invasive infection/bacteremia).

RESULTS

Safety data were available on 28 patients. LCS was cultured from the feces of five of the six study subjects who opened bowels during their stay on the pediatric intensive care unit. There was no evidence of either colonization or bacteremia with LCS in bacteriologic cultures obtained from study subjects. The preparation was well tolerated with no apparent side effects.

CONCLUSIONS

Our pilot safety study suggests that the use of LCS as a probiotic in enterally fed CIC is safe.

Lactic Acid Bacteria Production From Whey

The main purpose of this work was to isolate and characterize lactic acid bacteria (LAB) strains to be used for biomass production using a whey-based medium supplemented with an ammonium salt and with very low levels of yeast extract (0.25 g/L). Five strains of LAB were isolated from naturally soured milk after enrichment in whey-based medium. One bacterial isolate, designated MNM2, exhibited a remarkable capability to utilize whey lactose and give a high biomass yield on lactose. This strain was identified as Lactobacillus casei by its 16S rDNA sequence. A kinetic study of cell growth, lactose consumption, and titratable acidity production of this bacterial strain was performed in a bioreactor. The biomass yield on lactose, the percentage of lactose consumption, and the maximum increase in cell mass obtained in the bioreactor were 0.165 g of biomass/g of lactose, 100%, and 2.0 g/L, respectively, which were 1.44, 1.11, and 2.35 times higher than those found in flask cultures. The results suggest that it is possible to produce LAB biomass from a whey-based medium supplemented with minimal amounts of yeast extract.

Ribotyping of Lactobacillus casei group strains isolated from dairy products

A series of lactobacilli isolated from dairy products were characterized using biotyping and ribotyping with EcoRI and HindIII restriction enzymes. Biotyping assigned 14 strains as Lactobacillus casei, 6 strains as Lactobacillus paracasei subsp. paracasei and 12 as Lactobacillus rhamnosus. The obtained ribotype patterns separated all analyzed strains into two clearly distinguished groups corresponding to L. rhamnosus and L. casei/L. paracasei subsp. paracasei. The HindIII ribotypes of individual strains representing these two groups were visually very similar. In contrast, EcoRI ribotyping revealed high intraspecies variability. All ribotypes of L. casei and L. paracasei subsp. paracasei dairy strains were very close and some strains even shared identical ribotype profiles. The type strains L. casei CCM 7088T (= ATCC 393T) and Lactobacillus zeae CCM 7069T revealing similar ribopatterns formed a separate subcluster using both restriction enzymes. In contrast, the ribotype profile of L. casei CCM 7089 (= ATCC 334) was very close to ribopatterns obtained from the dairy strains. These results support synonymy of L. casei and L. paracasei species revealed by other studies as well as reclassification of the type strain L. casei CCM 7088T as L. zeae and designation of L. casei CCM 7089 as the neotype strain.

Oral lactobacilli in chronic periodontitis and periodontal health: species composition and antimicrobial activity

BACKGROUND/AIMS

Lactobacilli are known to play an important role in the maintenance of health by stimulating natural immunity and contributing to the balance of microflora. However, their role in chronic periodontitis is unclear. We aimed to identify oral lactobacilli in chronic periodontitis and periodontally healthy subjects, and to determine their antimicrobial activity against putative oral pathogens.

METHODS

A total of 238 Lactobacillus isolates from the saliva and subgingival sites of 20 chronic periodontitis and 15 healthy subjects were collected. In all, 115 strains were identified using rapid amplified ribosomal DNA restriction analysis. Antimicrobial activity against Streptococcus mutans, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia was assessed.

RESULTS

Lactobacilli belonging to 10 species were identified. The most prevalent strains in healthy persons were Lactobacillus gasseri and Lactobacillus fermentum and in chronic periodontitis patients, Lactobacillus plantarum. Obligately homofermentatives, particularly L. gasseri, were less prevalent in chronic periodontitis patients compared with healthy subjects (8% vs. 64% for L. gasseri, P < 0.01). Sixty-nine percent of tested lactobacilli inhibited S. mutans, 88% A. actinomycetemcomitans, 82% P. gingivalis and 65% P. intermedia. The strongest antimicrobial activity was associated with Lactobacillus paracasei, L. plantarum, Lactobacillus rhamnosus, and Lactobacillus salivarius. The strains from periodontally healthy patients showed a lower antimicrobial activity against S. mutans than the strains from chronic periodontitis patients.

CONCLUSION

The composition of oral lactoflora in chronic periodontitis and healthy subjects differs, with a higher prevalence of homofermentative lactobacilli, particularly L. gasseri, in the latter group. Both homo- and heterofermentative oral lactobacilli suppress the growth of periodontal pathogens, but the antimicrobial properties are strain, species and origin specific.

In situ and non-invasive detection of specific bacterial species in oral biofilms using fluorescently labeled monoclonal antibodies

Noninvasive in situ detection of suspected cariogenic bacterial species within dental biofilms could facilitate monitoring of the dynamic change of oral microbial flora and assist in the assessment of the treatment efficacy of therapeutic agents. In this study, we explore the possibility to use three well-characterized monoclonal antibodies (MAbs) against Streptococcus mutans, Actinomyces naeslundii, and Lactobacillus casei to identify these three important members of the oral microbial community in the complex environment of oral biofilms. These MAbs, which were conjugated to different fluorescent labels and visualized with confocal laser scanning microscopy (CLSM), proved to be an useful tool to identify the three species of interest (S. mutans, A. naeslundii, and L. casei) under various experimental conditions including in vitro and in vivo derived oral biofilms. Manifold addition of the MAbs on consecutive days did not alter the biofilm structure thus allowing monitoring of the same biofilm over extended time periods. Using this MAb-based method the effect of sucrose challenge on the biofilm composition and the distribution of S. mutans, A. naeslundii, and L. casei were examined. S. mutans was found to be the predominant species under the various biofilm conditions tested. These studies indicate that MAbs based bacterial detection with CLSM is a versatile tool which permits new insights into the ecology of oral biofilm development.

Lactobacillus casei improves resistance to pneumococcal respiratory infection in malnourished mice

We studied the effect of Lactobacillus casei CRL 431 used as a supplement in a repletion diet on the resistance to Streptococcus pneumoniae respiratory infection in malnourished mice. Weaned mice were malnourished after they consumed a protein-free diet (PFD) for 21 d. Malnourished mice were fed a balanced conventional diet (BCD) with or without supplemental L. casei for 7, 14, or 21 consecutive days, or BCD for 7 d with L. casei supplementation on d 6 and 7 (7dBCD+2dLc). The malnourished control (MNC) group was fed only the PFD, whereas well-nourished control (WNC) mice consumed the BCD ad libitum. Mice were challenged with S. pneumoniae at the end of each dietary treatment. Lung colonization and bacteremia were significantly greater in MNC than in WNC. Normalization of the immune response occurred in malnourished mice fed the BCD for 21 d. L. casei supplementation reduced the time required for a normal response from 21 to 7 d. Mice administered the 7dBCD+2dLc repletion treatment had a more effective pathogen clearance from blood and significantly lower lung damage than MNC. This treatment improved both the number of leukocytes and neutrophils in blood and bronchoalveolar lavages (BAL) and the bactericidal function of phagocytic cells to levels that did not differ from those of WNC. In the 7dBCD+2dLc mice, antipneumococcal IgA in BAL was higher than in WNC, whereas antipneumococcal IgG in serum and BAL did not differ. This study suggests that the addition of L. casei to the repletion diet has a beneficial effect because it accelerates the recovery of the innate immune response and improves the specific immune mechanisms against an S. pneumoniae respiratory infection in malnourished mice.

Initiation of protein synthesis by a labeled derivative of the Lactobacillus casei DN-114 001 strain during transit from the stomach to the cecum in mice harboring human microbiota

Although studies on the survival of bacteria in the digestive tract have been reported in the literature, little data are available on the physiological adaptation of probiotics to the digestive environment. In previous work, a transcriptional fusion system (i.e., luciferase genes under the control of a deregulated promoter) was used to demonstrate that a derivative of the Lactobacillus casei DN-114 001 strain, ingested in a fermented milk and thus exhibiting initially a very weak metabolic activity, synthesized proteins de novo after its transit in the digestive tract of mice harboring human microbiota (known as human-microbiota-associated mice). With the same genetic system and animal model, we here investigate for the first time the ability of L. casei to reinitiate synthesis in the different digestive tract compartments. In this study, most ingested L. casei cells transited from the stomach to the duodenum-jejunum within 1 h postingestion. No luciferase activity was observed in these digestive tract compartments after the first hour. At later times, the bulk of bacteria had transited to the ileum and the cecum. Luciferase synthesis was detected between 1.5 and 2.0 h postingestion at the ileal level and from 1.5 h to at least 6.0 h postingestion in the cecum, where the activity remained at a maximum level. These results demonstrate that ingested L. casei (derivative of the DN-114 001 strain) administered via a fermented milk has already reinitiated protein synthesis when it reaches the ileal and cecal compartments.

Isolation and characterization of lactobacilli from some traditional fermented foods and evaluation of the bacteriocins

Lactic acid bacteria (LAB) commonly used in food as starter cultures are known to produce antimicrobial substances such as bacteriocins and have great potential as food biopreservatives. LAB isolated from traditional fermented foods (appam batter and pickles) were screened for bacteriocin production. Two lactobacilli, LABB and LABP (one from each source) producing bacteriocins were characterized. Both the bacilli were homo-fermentative, catalase negative and micro-aerophilic in nature. LABB was found to be a thermobacterium growing at 45 degrees C while LABP was a streptobacterium growing at 15 degrees C. Both were able to grow at pH 4.5-8.6 but were intolerant to high salt concentration. They failed to produce gas from glucose as well as ammonia from arginine. Among the sugars examined they could not ferment arabinose, raffinose, rhamnose or xylose. Additionally, LABB could not ferment esculin, gluconate or mannose. LABB is identified as Lactobacillus acidophilus while LABP as Lb. casei. Their bacteriocins showed a broad inhibitory spectrum against the indicator organisms tested. They were active below pH 8.0 and after autoclaving as well. There was a complete loss of activity when treated with proteolytic enzymes such as trypsin indicating the proteinaceous nature of the active molecules. SDS-PAGE of partially purified bacteriocins indicated the molecular mass of the bacteriocin as 3.8 and 4.5 kDa for LABB and LABP respectively.

Transition of the probiotic bacteria, Lactobacillus casei strain Shirota, in the gastrointestinal tract of a pig

The transition of probiotic bacteria Lactobacillus in the gastrointestinal tract was investigated in pigs that received commercially available fermented milk prepared with Lactobacillus casei strain Shirota (LCS). Three female pigs fistulated at the cecum were fed 130 ml of fermented milk that contained over 10(10) (cfu) LCS with their daily meal for 8 days. Cecal contents were sampled through a fistula every 2 h for 24 h after marker dosing. The viable cell number (log cfu/g) of LCS and the concentrations of transit markers in each sample were determined. The viable number of LCS cells ranged from 3.56 to 6.58. The number of LCS in the cecum was not stable in pigs and varied with the flow of the cecal content. The viable number of LCS cells was significantly correlated with the relative concentration of the marker. These results indicated that most LCS moved with the liquid component. The level of LCS reached the maximum (6.38) 6 h after dosing. Four doses every 6 h may be required to maintain the maximum level of LCS at the cecum.

Case of aortic endocarditis caused by Lactobacillus casei

A case of Lactobacillus aortic valve endocarditis in a 53-year-old immunocompetent patient with past history of rheumatic fever is reported. Clinical symptoms began after a dental extraction and the patient's diet included several yogurts per day. Blood, bone marrow cultures and the replaced aortic valve were positive for Lactobacillus: The clinical isolate was identified as Lactobacillus casei by 16S rDNA sequencing.

Lactobacillus casei, dominant species in naturally fermented Sicilian green olives

This study investigated the phenotypic and genotypic characteristics of lactic acid bacteria in naturally fermented green olives, collected from different areas of Sicily. Both classical biochemical tests and PCR/Restriction Fragments Length Polymorphism (RFLP) of 16S rDNA were used to characterize the isolates. The identity of the isolates was obtained by the partial sequencing analysis of the 16S rDNA. The BioMerieux software assigned the 13 heterofermentative strains to the Lactobacillus brevis species; 24 homofermentative strains were classified as Lactobacillus casei and the remaining 11 homofermentative lactobacilli were identified as Lactobacillus plantarum. The rapid ID 32 STREP test identified coccal-shaped strains as Enterococcus faecium species. The PCR/RFLP analysis showed a remarkable bacterial heterogeneity within the isolates. The 16S rDNA partial sequencing did not confirm biochemical identification, revealing a strong dominance of isolates belonging to the L. casei species. It is noteworthy that this species has never been reported as dominant species in fermented vegetables.A combination of molecular and biochemical analysis allowed the identification of species involved in natural food fermentations.

Use of Group-Specific and RAPD-PCR Analyses for Rapid Differentiation of Lactobacillus Strains from Probiotic Yogurts

The increasing interest in probiotic lactobacilli implicates the requirement of techniques that allow a rapid and reliable identification of these organisms. In this study, group-specific PCR and RAPD-PCR analyses were used to identify strains of the Lactobacillus casei and Lactobacillus acidophilus groups most commonly used in probiotic yogurts. Group-specific PCR with primers for the L. casei and L. acidophilus groups, as well as L. gasseri/johnsonii, could differentiate between 20 Lactobacillus strains isolated from probiotic yogurts and assign these into the corresponding groups. For identification of these strains to species or strain level, RAPD profiles of the 20 Lactobacillus strains were compared with 11 reference strains of the L. acidophilus and L. casei group. All except one strain could be attributed unambigously to the species L. acidophilus, L. johnsonii, L. crispatus, L. casei, and L. paracasei. DNA reassociation analysis confirmed the classification resulting from the RAPD-PCR.

Influence of Adjunct Use and Cheese Microenvironment on Nonstarter Bacteria in Reduced-Fat Cheddar-Type Cheese

This study investigated population dynamics of starter, adjunct, and nonstarter lactic acid bacteria (NSLAB) in reduced-fat Cheddar and Colby cheese made with or without a Lactobacillus casei adjunct. Duplicate vats of cheese were manufactured and ripened at 7 degrees C. Bacterial populations were monitored periodically by plate counts and by DNA fingerprinting of cheese isolates with the random amplified polymorphic DNA technique. Isolates that displayed a unique DNA fingerprint were identified to the species level by partial nucleotide sequence analysis of the 16S rRNA gene. Nonstarter biota in both cheese types changed over time, but populations in the Colby cheese showed a greater degree of species heterogeneity. The addition of the L. casei adjunct to cheese milk at 10(4) cfu/ml did not completely suppress "wild" NSLAB populations, but it did appear to reduce nonstarter species and strain diversity in Colby and young Cheddar cheese. Nonetheless, nonstarter populations in all 6-mo-old cheeses were dominated by wild L. casei. Interestingly, the dominant strains of L. casei in each 6-mo-old cheese appeared to be affected more by adjunct treatment and not cheese variety.

Extent of genetic lesions of the arginine and pyrimidine biosynthetic pathways in Lactobacillus plantarum, L. paraplantarum, L. pentosus, and L. casei: prevalence of CO(2)-dependent auxotrophs and characterization of deficient arg genes in L. plantarum

Lactic acid bacteria require rich media since, due to mutations in their biosynthetic genes, they are unable to synthesize numerous amino acids and nucleobases. Arginine biosynthesis and pyrimidine biosynthesis have a common intermediate, carbamoyl phosphate (CP), whose synthesis requires CO(2). We investigated the extent of genetic lesions in both the arginine biosynthesis and pyrimidine biosynthesis pathways in a collection of lactobacilli, including 150 strains of Lactobacillus plantarum, 32 strains of L. pentosus, 15 strains of L. paraplantarum, and 10 strains of L. casei. The distribution of prototroph and auxotroph phenotypes varied between species. All L. casei strains, no L. paraplantarum strains, two L. pentosus strains, and seven L. plantarum strains required arginine for growth. Arginine auxotrophs were more frequently found in L. plantarum isolated from milk products than in L. plantarum isolated from fermented plant products or humans; association with dairy products might favor arginine auxotrophy. In L. plantarum the argCJBDF genes were functional in most strains, and when they were inactive, only one gene was mutated in more than one-half of the arginine auxotrophs. Random mutation may have generated these auxotrophs since different arg genes were inactivated (there were single point mutations in three auxotrophs and nonrevertible genetic lesions in four auxotrophs). These data support the hypothesis that lactic acid bacteria evolve by progressively loosing unnecessary genes upon adaptation to specific habitats, with genome evolution towards cumulative DNA degeneration. Although auxotrophy for only uracil was found in one L. pentosus strain, a high CO(2) requirement (HCR) for arginine and pyrimidine was common; it was found in 74 of 207 Lactobacillus strains tested. These HCR auxotrophs may have had their CP cellular pool-related genes altered or deregulated.

Production and characterization of species-specific monoclonal antibodies against Actinomyces naeslundii and Lactobacillus casei

Dental caries is a disease induced by a few cariogenic bacterial species. Quantitative detection of these cariogenic bacteria could provide useful information for caries risk assessment. In this study, we developed highly species-specific monoclonal antibodies (MAbs) against the type strains of Actinomyces naeslundii ATCC 12104 and Lactobacillus casei ATCC 11578. Assayed with immunoprecipitation and immunofluorescent microscopy, these antibodies showed high sensitivities and specificities in detecting A. naeslundii and L. casei in saliva. Examining 100 saliva samples using these MAb-based techniques, we found that the number of A. naeslundii in saliva ranges from 0.5 x 10(4) to 4.8 x 10(5) and that the number of L. casei in saliva ranges from 1 x 10(4) to 1.2 x 10(6). With fluorescent imaging techniques and confocal laser scanning microscopy (CLSM), these antibodies were used to visualize A. naeslundii and L. casei within dental plaques derived from stimulated whole human saliva in vitro. The study demonstrated that these MAbs were also able to effectively detect A. naeslundii and L. casei in plaque.

Molecular diagnosis of endocarditis due to Lactobacillus casei subsp. rhamnosus

We report a case of endocarditis due to Lactobacillus casei subsp. rhamnosus. The bacterium isolated from blood cultures and from valve tissue specimens was identified using both phenotypical analysis and DNA sequence analysis, which revealed that the rod profiles of the pathogens recovered from blood cultures and valve tissue specimens were the same.

Lactobacillus casei subsp. rhamnosus sepsis in a patient with ulcerative colitis

Lactobacillus species are part of normal gastrointestinal flora and are an uncommon cause of bacteremia. Lactobacillus casei subsp. rhamnosus was repeatedly isolated in the blood cultures of a 43-year-old woman with ulcerative colitis. Lactobacillus spp. could be considered a potential opportunistic pathogen whenever there is disruption of the physiologic architecture of the intestinal mucosa, such as in abdominal surgery, endoscopic procedures, or enteric pathologies. Clinicians and clinical microbiologists need to be aware of this infective complication in patients with ulcerative colitis.