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PubMed2004

[Evaluation of the effect of probiotic cultures on two different yogurt brands over a known population of Staphylococcus aureus and the production of thermonuclease].

The effect of probiotic cultures over known populations of Staphylococcus aureus inoculated in yogurt was studied; also the production and stability of its thermonuclease during yogurt storage was evaluated. In three different occasions, two different yogurt brands, one with additional probiotic cultures (Lactobacillus casei and L. acidophilus), were inoculated with known populations of S. aureus in high and low concentration (10(9) CFU/g and 10(7) CFU/g), respectively. These samples were stored for 28 days at 5 degrees C. Every four days the count of lactic bacteria, S. aureus and pH were evaluated, according to the methodology described in the Compendium of Methods for the Microbiological Examination of Foods, Vanderzant & Splittstoesser. The presence of thermonuclease was determined using petrifilm for S. aureus from 3M company. The pH and lactic bacteria population were constant during the testing period. Yogurt with additional probiotic cultures (high and low concentration) lowered the population of S. aureus to non detectable levels in 8 days; but, S. aureus could be cultured from yogurt without probiotics even after 24 days of incubation. Same time, the presence of thermonuclease was positive in all tests; it was not affected by probiotics. The presence of thermonuclease is related to the production of S. aureus enterotoxin. This work emphasizes again the beneficial effects of probiotic cultures in yogurt over bacteria and the importance of keeping hygienic practices in order to avoid the contamination of food with S. aureus and the eventual production of its enterotoxin, since it is not affected by probiotics.

Animals↗

PubMed2005

Probiotics in inflammatory bowel disease: possible mechanisms of action.

PURPOSE OF REVIEW: Probiotics are live, nonpathogenic bacteria that confer health benefits beyond their nutritional value. In inflammatory bowel disease, where changes in bacterial flora have been demonstrated, there is an increasing interest in modulating the flora with probiotic strains. The beneficial effect of probiotics is demonstrated mainly in pouchitis and ulcerative colitis; however, their mechanisms of action are not well defined. The purpose of this review is to discuss the latest findings related to their mechanism of action. RECENT FINDINGS: A decrease in the secretion of pro-inflammatory cytokines, IFN-gamma, TNF-alpha and IL-12, and interference with bacterial adherence to the epithelium has been demonstrated. At the molecular level, an anti-inflammatory effect associated with NF-kappaB inhibition, heat-shock protein induction and proteasome inhibition has been suggested, although NF-kappaB induction has also been demonstrated. Unexpectedly, the beneficial effects described were achieved not only by live bacteria but also by gamma-irradiated nonviable bacteria, bacterial DNA components and probiotic-cultured media. SUMMARY: Understanding the mechanisms responsible for the beneficial effect of probiotics in inflammatory bowel disease and experimental colitis may help understand the role of bacteria in disease pathogenesis. The findings that live probiotics may not be mandatory to be beneficial, and that therapeutic effects may be obtained by systemic, rather than oral administration could have a major impact on the practical use and manufacturing of probiotics.

Animals↗

PubMed1996

The effect of Saccharomyces cerevisiae and Aspergillus oryzae on fermentations in the rumen of faunated and defaunated sheep; protozoal and probiotic interactions.

We measured the effect of the direct addition to the rumen of Saccharomyces cerevisiae (SC 50 mg/day) and Aspergillus oryzae (AO 3 g/day) on the fermentation processes in fistulated sheep. The measurements were carried out on animals whose rumens were first defaunated and then refaunated. The animals received a ration composed of hay (600 g/day), barley (600 g/day) and soybean meal (150 g/day), fed twice daily in two equal meals. The number of fungi and total, viable or cellulolytic bacteria were lower after the inoculation of protozoa in defaunated rumens. The probiotics stimulated the development of total bacteria but reduced the population of cellulolytic bacteria. The addition of the probiotics and the presence of protozoa each incurred a decrease in the redox potential values. The association of both treatments had an additive effect on this parameter. The two probiotics and the protozoa stabilized the rumen pH after the meal, maintaining it above the value of 6 for a longer period of time. The positive effects on pH were accumulated in the refaunated animals receiving probiotics. The ammonia nitrogen concentration was considerably increased by the presence of the protozoa; the probiotics increased the ammonia concentration only in the refaunated sheep. The methane and hydrogen proportions in the fermentation gases were invariably higher in the refaunated animals. The probiotics had no clear effect either on the gas composition or the concentration and the composition of the mixture of volatile fatty acids; only the concentration of isovalerate was significantly increased by probiotics and only in refaunated animals. The protozoa did, however, considerably increase the concentrations of acetate, butyrate and isoacids and decreased the concentration of caproate.

Ammonia↗

PubMed1997

Biotherapeutic effects of probiotic bacteria on candidiasis in immunodeficient mice.

Four species of probiotic bacteria were assessed for their capacities to protect athymic bg/bg-nu/nu and euthymic bg/bg-nu/+ mice from mucosal and systemic candidiasis. Each bacterial species and Candida albicans colonized the gastrointestinal tracts of both strains of mice. The presence of probiotic bacteria (Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus casei GG, or Bifidobacterium animalis) in the gastrointestinal tracts prolonged the survival of adult and neonatal bg/bg-nu/nu mice compared to that of isogenic mice colonized with C. albicans alone. The incidence of systemic candidiasis in bg/bg-nu/nu mice was significantly reduced by each of the four probiotic bacterial species. The numbers of C. albicans present in the alimentary tracts of euthymic bg/bg-nu/+ mice were significantly reduced by L. casei GG and B. animalis. None of the probiotic bacteria species completely prevented mucosal candidiasis, but B. animalis reduced its incidence and severity. Probiotic bacteria also modulated antibody- and cell-mediated immune responses to C. albicans. The prolonged survival of mice, decreased severity of mucosal and systemic candidiasis, modulation of immune responses, decreased number of C. albicans in the alimentary tract, and reduced numbers of orogastric infections demonstrated not only that probiotic bacteria have biotherapeutic potential for prophylaxis against and therapy of this fungal disease but also that probiotic bacteria protect mice from candidiasis by a variety of immunologic (thymic and extrathymic) and nonimmunologic mechanisms in this model.

Adjuvants, Immunologic↗

PubMed2000

Effects of probiotic bacteria on humoral immunity to Candida albicans in immunodeficient bg/bg-nu/nu and bg/bg-nu/+ mice.

Germfree beige-nude ( bg/bg-nu/nu) and beige-heterozygous ( bg/bg-nu/+) mice were colonized with a pure culture of Candida albicans or with a probiotic bacterium (Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus casei, or Bifidobacterium infantis). Probiotic-colonized mice were subsequently challenged orally with C. albicans. The effect of prior colonization with probiotic bacteria on the antibody responses of the immunodeficient mice to alimentary tract colonization with C. albicans was compared to the antibody responses of the gnotobiotic mice colonized only with C. albicans. This study demonstrated that, although the probiotic bacteria did not induce a vigorous antibody response to their own antigens, they altered the antibody responses of mice to C. albicans. In T cell competent bg/bg-nu/+mice, B. infantis enhanced and focused IgG1, IgG2A, and IgA responses to C. albicans antigens. Some of the probiotic bacteria also enhanced the IgG1 and IgG2A antibody responses of bg/bg-nu/nu mice to C. albicans antigens. This study not only shows the value of gnotobiotic animal models in demonstrating that probiotic bacteria can affect the capacity of mice to form antibodies to C. albicans, but it also points out their usefulness in comparing the capacity of different probiotic bacteria to produce beneficial health effects in mice.

Journal Article↗

PubMed1992

[Probiotics].

Probiotics, living cultures of micro-organisms, are currently of great interest as counterparts to antibiotics. The idea behind the use of probiotics is that the development and stability of intestinal microflora can be enhanced. The protection against infections is increased, resulting in fewer health problems and increased productivity. The mechanism of action of probiotics is not yet known, although there are several hypotheses. There is increasing evidence to suggest that probiotics act by stimulating the host's immune systems. The only accepted example of effective protection against infections provided by living micro-organism is the 'Nurmi concept', whereby one-day-old chicks acquire an enhanced protection against Salmonella infections when they are administered the complex intestinal flora of older chicks. The effects of probiotics on the growth, feed conversion or production of farm animals are, even in specific situations, not consistent enough to consider their use out of economic considerations. Probiotics are used to (re)establish the intestinal flora of patients or persons with lactose intolerance. The claims that probiotics have cholesterol-lowering and anti-tumour actions are based on animal experiments and require further investigations.

Animal Nutritional Physiological Phenomena↗

PubMed2026

Assessment of multiple probiotic strains that protect Montipora capitata coral from infection by Vibrio coralliilyticus.

Coral disease outbreaks threaten reef ecosystems, often leading to widespread mortality and declines in coral cover. Outbreaks of tissue loss diseases like acute Montipora white syndrome (aMWS) have impacted coral populations that include the Hawaiian rice coral (Montipora capitata). Multiple strains of Vibrio coralliilyticus are known pathogens, and strain OCN008 has been demonstrated as an etiological agent of aMWS in Hawai'i. Recent work has demonstrated that probiotic bacterial strains can be used to directly treat or prevent transmission (prophylaxis) of coral diseases. Based on their production of zones of inhibition and isolation from disease-resistant corals, Pseudoalteromonas ardens R96, Pseudoalteromonas obscura P94, strain Y97 (the genomic similarity to Pseudoalteromonas piscicida is presented), Pseudoalteromonas umbrosa B95, and Vibrio tetraodonis subsp. pristinus OCN044 were assessed for their ability to impair V. coralliilyticus OCN008 infection of M. capitata during laboratory infection trials. Individual inoculation of each of the five aforementioned strains on M. capitata fragments for 48 h prior to V. coralliilyticus OCN008 inoculation resulted in up to a 93.75% reduction in mortality. These results indicate that strains of Pseudoalteromonas and Vibrio can act as prophylactics to prevent M. capitata mortality from V. coralliilyticus OCN008 infection and provide tools to improve disease resilience for Pacific corals.IMPORTANCECoral disease outbreaks are a growing threat to the continued health of coral reefs, which are already vulnerable ecosystems. Strains of the bacterium Vibrio coralliilyticus are known to infect various coral species worldwide, predominantly causing tissue loss and death of the coral animal. Previous research has indicated that constituents from healthy coral microbiomes can act as probiotics to treat or prevent coral infections, and the discovery of effective probiotics is important in the effort to further develop mitigation tools for disease outbreaks. This work provides a demonstration of probiotic species that can protect coral from tissue loss infections by a strain of Vibrio coralliilyticus and is an example of probiotics developed for coral species in Hawai'i. This work provides new tools for probiotic-based coral protection and evidence for this research as a viable avenue to protect coral in their native environments.

Animals↗

PubMed2004

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.

Adult↗

PubMed2001

Probiotics and functional foods in gastrointestinal disorders.

Probiotics are live microbial food supplements that benefit the host animal by improving intestinal microbial balance. When they are fed in yogurts, they can fall into the category of functional foods. Functional foods include these probiotics, prebiotics, and, to a certain extent, dietary fiber. Prebiotics are nondigestible food ingredients or supplements that alter the intestinal flora and stimulate the growth of healthy bacteria. Dietary fibers are part of plant foods that are nonstarch polysaccharides and are poorly digested or not digested by human enzymes. The physiologic process in which probiotics and functional foods affect the intestinal flora is through the balance of the intestinal microecology. This review looks at the four major components of intestinal microecology and describes the probiotics in use today and their clinical relevance. Although probiotics hold great promise and appear to be useful in some settings, more clinical study is needed to firmly establish the relevance of probiotic therapy.

Dietary Fiber↗

PubMed2004

An investigation into the effect of a probiotic on gut immune function in surgical patients.

BACKGROUND: The gut-associated lymphoid tissue (GALT) is an important component of the gut barrier. We have previously demonstrated a significant increase in various parameters of gut immune function in association with bacterial translocation. Animal studies have suggested that the probiotic Lactobacillus plantarum 299v improves the immunological status of the intestinal mucosa. The aim of this study was to determine whether the same is true in humans. METHOD: This was a prospective randomised controlled study, in which immunohistochemical techniques were used to measure the concentrations of plasma cells, IgA positive cells and IgM positive cells in the lamina propria, together with the concentrations of IgA and IgM at the mucosal surface in specimens of normal small bowel obtained from patients undergoing elective abdominal surgery who had consumed an oral preparation containing the probiotic Lactobacillus plantarum 299v (ProViva) during the immediate preoperative period. These were compared with similar specimens obtained from control subjects who did not receive the probiotic. RESULTS: A total of 22 patients were studied (probiotic group n = 11, control group n = 11). The median volume of ProViva consumed was 3250 ml (range 2100-9000 ml), for a median duration of 9 days (range 5-18 days). There were no significant differences between the probiotic and control groups in terms of concentrations of plasma cells, IgA positive cells or IgM positive cells in the lamina propria. There was a significantly higher concentration of IgM at the mucosal surface in the control group (P = 0.02, Fishers Exact test mid P), but no difference in terms of IgA. CONCLUSIONS: The increase in IgA observed in the intestinal mucosa in response to probiotics in animal studies does not occur in humans. The significance of the increase in IgM at the mucosal surface in the controls is unclear.

Adult↗

PubMed2006

Towards understanding molecular modes of probiotic action.

The possibility that certain microorganisms might be beneficial to human health is highlighted by the numerous consumer products containing probiotic bacteria. Probiotics are typically administered in food that, following entry into the gastro-intestinal tract, results in measurable health-promoting effects. Although there is a growing list of health benefits provided by the consumption of probiotics, their precise mechanisms of action remain largely unknown. Recent molecular- and genomics-based studies are starting to provide insight into the ways probiotic bacteria sense and adapt to the gastro-intestinal tract environment. Complementary approaches using host cell in vitro systems together with animal models and human volunteers are revealing specific intestinal cell responses to probiotics. These studies should ultimately disclose the molecular mechanisms and pinpoint the bacterial and host effector molecules and pathways by which probiotics are able to modulate human health.

Animals↗

PubMed2005

Probiotics and nutraceuticals: non-medicinal treatments of gastrointestinal diseases.

The demonstration that immune and epithelial cells can discriminate between different microbial and bioactive plant species has extended the known mechanism(s) of action of nutraceuticals and probiotics beyond simple nutrition and/or antimicrobial effects. The progressive unravelling of these plant and bacterial effects on systemic immune and intestinal epithelial cell function has led to new credence for the use of probiotics and nutraceuticals in clinical medicine. Level I evidence now exists for the therapeutic use of probiotics in infectious diarrhea in children, recurrent Clostridium difficile-induced infections and post-operative pouchitis. Additional evidence is being acquired for the use of probiotics in other gastrointestinal infections, irritable bowel syndrome and inflammatory bowel disease. Not all individual probiotic strains have the same efficacy, and future clinical trials may focus on multistrain preparations agents with known efficacy. The use of nutraceuticals and probiotics as therapeutic agents for gastrointestinal disorders is rapidly moving into clinical usage. Scientific studies are providing mechanisms of action to explain the therapeutic effects, and randomized controlled trials are providing the necessary evidence for their incorporation into the therapeutic armamentarium.

Colorectal Neoplasms↗

PubMed2004

Patterns of cytokine induction by gram-positive and gram-negative probiotic bacteria.

Bacteria used in commercial probiotic preparations are most commonly gram-positive lactic acid-producing species, although there are also some probiotic products which utilise gram-negative coliform bacteria. Characterising how the innate immune system responds to these bacteria in vitro may give an indication as to the likely immunomodulatory events that can be triggered following probiotic administration in vivo. Here, an established gram-positive probiotic (Lactobacillus casei Shirota) was compared against a novel gram-negative probiotic strain (Escherichia coli Nissle 1917) for its ability to induce cytokine production in a cell type representative of the innate immune system; in addition, responses were contrasted against those induced by an enteropathogenic coliform, E. coli 2282. We investigated the ability of these three bacterial strains to modulate production of interleukins-10, -12 and -18; tumour necrosis factor-alpha; interferon-alpha; and transforming growth factor-beta, via a series of in vitro culture experiments involving the murine monocyte/macrophage cell line J774A.1. All bacteria induced marked secretion of IL-12 and TNFalpha by cells, while only coliforms induced production of IL-10; there was minimal or no induction of IL-18 or TGFbeta. Activation of cells with recombinant gamma-interferon promoted increased production of IL-12, but decreased production of IL-10, in response to the co-culture of coliform bacteria, indicating differential cytokine induction depending on the activation status of the target cell. In general, live bacteria stimulated higher levels of IL-10, IL-12 and TNFalpha secretion than heat-killed preparations, while only live coliforms induced IFNalpha. These findings are discussed in relation to the likely immunomodulatory effects of gram-positive and gram-negative bacteria on the innate immune system in vivo, with particular emphasis on the marked similarity in cytokine response patterns observed between probiotic versus pathogenic coliform bacteria.

Animals↗

PubMed2005

Induction of inflammation as a possible mechanism of probiotic effect in atopic eczema-dermatitis syndrome.

BACKGROUND: The immunomodulating mechanisms of Lactobacillus GG (LGG) and other probiotics are poorly understood. OBJECTIVE: We studied in vivo the immunologic effects of probiotics in infants with atopic eczema-dermatitis syndrome (AEDS) and cow's milk allergy (CMA). METHODS: Two hundred thirty infants with AEDS and suspected CMA received, concomitant with elimination diet, either LGG, a mixture of 4 probiotic strains (MIX), or placebo for 4 weeks. All available paired pretreatment and posttreatment plasma samples (n = 132) were analyzed for concentrations of IL-2, IL-4, IL-6, IL-10, TNF-alpha, IFN-gamma, soluble intercellular adhesion molecule 1, soluble E-selectin, TGF-beta1, TGF-beta2, and C-reactive protein. RESULTS: In infants with IgE-associated AEDS, treatment with LGG induced higher C-reactive protein levels than in the placebo group (geometric mean, 0.83 microg/mL [95% CI, 0.56-0.81] vs 0.42 microg/mL [95% CI, 0.27-0.65]; P = .021). Concomitantly, IL-6 levels increased after treatment with LGG ( P = .023) but not with MIX or placebo. Soluble E-selectin levels were higher after probiotic than after placebo treatment in infants with IgE-mediated CMA (LGG geometric mean, 86.7 ng/mL [95% CI, 75.2-100]; MIX geometric mean, 91.6 ng/mL [95% CI, 74.8-111.9]; and placebo geometric mean, 64.9 ng/mL [95% CI, 53-79.3]; analysis of covariance, P = .035; LGG vs placebo, P = .023; MIX vs placebo, P = .020). Use of MIX induced an increase in plasma IL-10 levels ( P = .016). CONCLUSION: Probiotics induced systemically detectable low-grade inflammation, which might explain the clinical effects of probiotics in AEDS and CMA.

Animals↗

PubMed2004

Effects of soybean isoflavones, probiotics, and their interactions on lipid metabolism and endocrine system in an animal model of obesity and diabetes.

The effects of soybean isoflavones with or without probiotics on tissue fat deposition, plasma cholesterol, and steroid and thyroid hormones were studied in SHR/N-cp rats, an animal model of obesity, and were compared to lean phenotype. We tested the hypothesis that probiotics by promoting the conversion of isoflavone glycosides to their metabolically active aglycone form will have a synergistic effect on body fat, cholesterol metabolism, and the endocrine system. Obese and lean SHR/N-cp rats were fed AIN-93 diets containing 0.1% soy isoflavone mixture, 0.1% probiotic mixture, or both together. Different fat tissues were teased and weighed. Plasma was analyzed for cholesterol and steroid and thyroid hormones. In both phenotypes, isoflavones lowered fat deposition in several fat depots. Probiotics alone had no significant effect on fat depots. Isoflavones lowered total, LDL, and HDL cholesterol in lean rats, but in obese rats isoflavones lowered only total and LDL cholesterol. Isoflavones also lowered many of the steroid hormones involved in lipid metabolism but had no significant effect on thyroid hormones. Probiotics had no significant effect on cholesterol or hormones. Thus, our data show that soy isoflavones also lower plasma cholesterol and that this hypocholesterolemic effect appears to be due in part to the modulation of steroid hormones. Probiotics do not seem to enhance the effect of isoflavones.

Adipose Tissue↗

PubMed2006

Accuracy of species identity of commercial bacterial cultures intended for probiotic or nutritional use.

Independent studies have indicated that the microbiological composition of several commercial probiotic products does not correspond to the product label information. The present study set out to investigate to what extent these problems may be due to the use of misidentified cultures at the onset of production. For this purpose, 213 cultures of lactic acid bacteria (LAB) and propionibacteria intended for probiotic or nutritional use were collected from 26 manufacturers of probiotic products, three international culture collections and one research institute. The accuracy of the taxonomic identity provided by the strain depositor was assessed through a polyphasic approach based on validated and standardized identification methods including fluorescent amplified fragment length polymorphism (FAFLP) and repetitive DNA element (rep)-PCR fingerprinting, protein profiling and partial 16S rDNA sequencing. The majority of the cultures were received as members of the genera Lactobacillus (57%) and Bifidobacterium (22%); however, propionibacteria, enterococci, Lactococcus lactis (subsp. lactis), Streptococcus thermophilus and pediococci were also obtained. Upon reidentification, 46 cases of misidentification at the genus level (n=19) or species level (n=27) were recorded, including 34 commercial probiotic cultures deposited by 10 different companies. The finding that more than 28% of the commercial cultures intended for human and/or animal probiotic use were misidentified at the genus or species level suggests that many cases of probiotic product mislabeling originate from the incorporation of incorrectly identified strains. A large number of these discrepancies could be related to the use of methods with limited taxonomic resolution (e.g., API strips) or that are unsuitable for reliable identification up to species level (e.g., pulsed-field gel electrophoresis and randomly amplified polymorphic DNA analysis). The current study has again highlighted that reliable identification of LAB and propionibacteria requires molecular methods with a high taxonomic resolution that are linked to up-to-date identification libraries.

Bacteria↗

PubMed1998

Taxonomy and physiology of probiotic lactic acid bacteria.

The current taxonomy of probiotic lactic acid bacteria is reviewed with special focus on the genera Lactobacillus, Bifidobacterium and Enterococcus. The physiology and taxonomic position of species and strains of these genera were investigated by phenotypic and genomic methods. In total, 176 strains, including the type strains, have been included. Phenotypic methods applied were based on biochemical, enzymatical and physiological characteristics, including growth temperatures, cell wall analysis and analysis of the total soluble cytoplasmatic proteins. Genomic methods used were pulsed field gel electrophoresis (PFGE), randomly amplified polymorphic DNA-PCR (RAPD-PCR) and DNA-DNA hybridization for bifidobacteria. In the genus Lactobacillus the following species of importance as probiotics were investigated: L. acidophilus group, L. casei group and L. reuteri/L. fermentum group. Most strains referred to as L. acidophilus in probiotic products could be identified either as L. gasseri or as L. johnsonii, both members of the L. acidophilus group. A similar situation could be shown in the L. casei group, where most of the strains named L. casei belonged to L. paracasei subspp. A recent proposal to reject the species L. paracasei and to include this species in the restored species L. casei with a neotype strain was supported by protein analysis. Bifidobacterium spp. strains have been reported to be used for production of fermented dairy and recently of probiotic products. According to phenotypic features and confirmed by DNA-DNA hybridization most of the bifidobacteria strains from dairy origin belonged to B. animalis, although they were often declared as B. longum by the manufacturer. From the genus Enterococcus, probiotic Ec. faecium strains were investigated with regard to the vanA-mediated resistance against glycopeptides. These unwanted resistances could be ruled out by analysis of the 39 kDa resistance protein. In conclusion, the taxonomy and physiology of probiotic lactic acid bacteria can only be understood by using polyphasic taxonomy combining morphological, biochemical and physiological characteristics with molecular-based phenotypic and genomic techniques.

Bifidobacterium↗

PubMed2004

In vitro growth characteristics of five candidate aquaculture probiotics and two fish pathogens grown in fish intestinal mucus.

The selection of probiotics for aquaculture is usually based on their antagonism towards pathogens. However, other criteria such as growth, attachment to intestinal mucus and production of beneficial compounds should also be considered. We suggest a protocol for the isolation and selection of potential probiotic bacteria based on their in vitro growth characteristics and propose a ranking index (RI) to screen potential aquaculture probionts. We suggest that the lag period and doubling time are the most important criteria for the comparison of growth curves, hence the RI is based on the doubling time (t(d)) and lag period (lambda) obtained from the growth profile of each bacterium. Bacteria were isolated from the gut of the common clownfish, Amphiprion percula, and screened for antagonistic activity towards seven aquatic pathogens. All five candidate probiotics showed antagonism to various aquatic pathogens. When grown in intestinal fish mucus no probiotic had a RI higher than the two tested pathogens (Aeromonas hydrophila and Vibrio alginolyticus). However, candidate probiont AP1 had a faster specific growth rate (micro) (0.05) than the pathogens (0.049 and 0.047 respectively), while AP5 grown in marine broth had a shorter lag period than the pathogens. Strategies to increase probiotic concentration include the inoculation of high concentrations and the preconditioning of these bacteria to reduce the lag period. It should be tested whether or not such strategies will allow the probiotic bacteria to dominate initially and thereby gain a competitive advantage. This could become an important aspect under in vivo conditions where both attachment and nutrient supply differ from that found in in vitro studies.

Aeromonas↗