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Antibiotics have contributed significantly to the improvement of animal health and to the availability of animal-derived foodstuffs. However, the routine use of antimicrobials in animal production has raised concerns not only about the potential presence of residues in foods but, particularly, about the development and spread of antibiotic-resistant bacteria that may compromise the treatment of animal and human infectious diseases. In this context, strategies to reduce antibiotic use and/or mitigate their collateral damage, especially the development of resistance and adverse effects on the host microbiota, must be developed. In this article, different strategies and lines of action or research are proposed to be applied within the framework of the Spanish National Plan for Antibiotic Resistance. [ABSTRACT FROM AUTHOR]

The colonic microbiota plays an important role in the bioavailibility of dietary polyphenols. This work has evaluated the impact on the gut microbiota of long-term feeding with both a red wine polyphenolic extract and the flavan-3-ol metabolizer strain Lactobacillus plantarum IFPL935. The study was conducted in the dynamic Simulator of the Human Intestinal Microbial Ecosystem (SHIME). The feeding of the gut microbiota model with red wine polyphenols caused an initial decrease in the counts of total bacteria in the ascending colon (AC), with Bacteroides, Clostridium coccoides/ Eubacterium rectale and Bifidobacterium being the most affected bacterial groups. The bacterial counts recovered to initial numbers faster than the overall microbial fermentation and proteolysis, which seemed to be longer affected by polyphenols. Addition of L. plantarum IFPL935 helped to promptly recover total counts, Lactobacillus and Enterobacteriaceae and led to an increase in lactic acid formation in the AC vessel at the start of the polyphenol treatment as well as butyric acid in the transverse (TC) and descending (DC) vessels after 5 days. Moreover, L. plantarum IFPL935 favoured the conversion in the DC vessel of monomeric flavan-3-ols and their intermediate metabolites into phenylpropionic acids and in particular 3-(3′-hydroxyphenyl)propionic acid. The results open the possibilities of using L. plantarum IFPL935 as a food ingredient for helping individuals showing a low polyphenol-fermenting metabotype to increase their colonic microbial capacities of metabolizing dietary polyphenols. [ABSTRACT FROM AUTHOR]

There is an increased interest in secondary plant metabolites, such as polyphenols and carotenoids, due to their proposed health benefits. Much attention has focused on their bioavailability, a prerequisite for further physiological functions. As human studies are time consuming, costly, and restricted by ethical concerns, in vitro models for investigating the effects of digestion on these compounds have been developed and employed to predict their release from the food matrix, bioaccessibility, and assess changes in their profiles prior to absorption. Most typically, models simulate digestion in the oral cavity, the stomach, the small intestine, and, occasionally, the large intestine. A plethora of models have been reported, the choice mostly driven by the type of phytochemical studied, whether the purpose is screening or studying under close physiological conditions, and the availability of the model systems. Unfortunately, the diversity of model conditions has hampered the ability to compare results across different studies. For example, there is substantial variability in the time of digestion, concentrations of salts, enzymes, and bile acids used, pH, the inclusion of various digestion stages; and whether chosen conditions are static (with fixed concentrations of enzymes, bile salts, digesta, and so on) or dynamic (varying concentrations of these constituents). This review presents an overview of models that have been employed to study the digestion of both lipophilic and hydrophilic phytochemicals, comparing digestive conditions in vitro and in vivo and, finally, suggests a set of parameters for static models that resemble physiological conditions. [ABSTRACT FROM AUTHOR]

The aims of this study were to estimate the prevalence of familial cases in patients with Meniere's disease ( MD) and to identify clinical differences between sporadic and familial MD. We recruited 1375 patients with definite MD according to the American Academy of Otolaryngology-Head and Neck Surgery criteria, obtaining the familial history of hearing loss or episodic vertigo by direct interview or a postal survey in 1245 cases in a multicenter study. Familial clustering was estimated by the recurrence risk ratio in siblings ( λs) and offspring ( λo) using intermediate and high prevalence values for MD in European population. A total of 431 patients (34%) reported a familial history of hearing loss or recurrent vertigo and 133 patients had a relative with possible MD. After clinical reevaluation, 93 relatives in 76 families were diagnosed of definite MD (8.4%), including three pairs of monozygotic twins. λs and λo were 16-48 and 4-12, respectively. We observed genetic heterogeneity, but most families had an autosomal dominant inheritance with anticipation. No clinical differences were found between sporadic and familial MD, except for an early onset in familial cases. We may conclude that MD has a strong familial aggregation and that sporadic and familial MDs are clinically identical. [ABSTRACT FROM AUTHOR]

Probiotic administration could prevent antibiotic-associated diarrhoea due to the restoration of an intestinal microbiota imbalance caused by antibiotics. The effect of the probiotics Lactobacillus acidophilus LA-5, Lactobacillus casei subsp. casei LC-01 and Bifidobacterium animalis subsp. lactis BB-12 on the composition and metabolic activities of the intestinal microbiota in human subjects during antibiotic treatment has been analyzed. Subjects that were placed on antibiotic therapy (amoxiciline/clavulanic or levofloxacin) were randomly assigned to receive a multispecies probiotic fermented milk ( n = 122) or a placebo fermented milk ( n = 125). Stool samples were collected at different intervals during the intervention study and analysed for faecal microbiota enumeration, probiotic species detection, enzyme activities and short chain fatty acid (SCFA) concentrations. The most predominant microbiota groups were total anaerobes, bacteroides and total aerobes. Probiotic species in fecal samples were analyzed by real-time PCR and results indicated that prevalence of the probiotic species within the probiotic group was below 50 % during the intervention study. Enzyme activities and SCFA concentrations showed a large inter-individual variability over the time in the placebo and probiotic groups, except to β-galactosidase activity, which was the most abundant in both groups over the time. In conclusion, the combination of L. acidophilus LA-5, L. casei subsp. casei LC-01 and B. animalis subsp. lactis Bb-12 taken in daily doses of 10-10 colony-forming units (CFU) does not significantly influence ( P > 0.05) either the fecal microbiota or its metabolic activity in elderly hospitalized patients taking amoxicillin/clavulanate or levofloxacin. In addition, this combination of probiotic strains did not reduce the rate of occurrence of diarrohea in these patients. [ABSTRACT FROM AUTHOR]

Aims: To investigate the effect of seven wine phenolic compounds and six oenological phenolic extracts on the growth of pathogenic bacteria associated with respiratory diseases ( Pseudomonas aeruginosa, Staphylococcus aureus, Moraxella catarrhalis, Enterococcus faecalis, Streptococcus sp Group F, Streptococcus agalactiae and Streptococcus pneumoniae). Methods and Results: Antimicrobial activity was determined using a microdilution method and quantified as IC50. Mor. catarrhalis was the most susceptible specie to phenolic compounds and extracts. Gallic acid and ethyl gallate were the compounds that showed the greatest antimicrobial activity. Regarding phenolic extracts, GSE (grape seed extract) and GSE-O (oligomeric-rich fraction from GSE) were the ones that displayed the strongest antimicrobial effects. Conclusions: Results highlight the antimicrobial properties of wine phenolic compounds and oenological extracts against potential respiratory pathogens. The antimicrobial activity of wine phenolic compounds was influenced by the type of phenolic compounds. Gram-negative bacteria were more susceptible than Gram-positive bacteria to the action of phenolic compounds and extracts; however, the effect was species-dependent. Significance and Impact of Study: The ability to inhibit the growth of respiratory pathogenic bacteria as shown by several wine phenolic compounds and oenological extracts warrants further investigations to explore the use of grape and wine preparations in oral hygiene. [ABSTRACT FROM AUTHOR]

Aims: The use of randomly amplified polymorphic DNA (RAPD)-PCR fingerprinting and plasmid profiles to determine at the strain level, the similarity of Lactococcus lactis isolates obtained during sampling of traditional cheeses and to verify its correspondence to the selected phenotypic characteristics. Methods and Results: A total of 45 L. lactis isolates were genotypically analysed by RAPD-PCR fingerprinting and plasmid patterns. Phenotypic traits used to compare strains were proteolytic, acidifying, aminotransferase (aromatic and branched chain aminotransferase) and α-ketoisovalerate decarboxylase (Kivd) activities. The results show that 23 isolates could be grouped in clusters that exhibited 100% identity in both their RAPD and plasmid patterns, indicating the probable isolation of dominant strains during the cheese sampling process. However, there were phenotypic differences between isolates within the same cluster that included the loss of relevant technological properties such as proteinase activity and acidifying capacity or high variation in their amino acid converting enzyme activities. Likewise, the analysis of a specific attribute, Kivd activity, indicated that 7 of 15 isolates showed no detectable activity despite the presence of the encoding ( kivd) gene. Conclusion: Phenotypic differences found between genotypically similar strains of L. lactis strains could be linked to differences in enzymatic expression. Significance and Impact of the Study: Phenotypic analysis of L. lactis isolates should be considered when selecting strains with new cheese flavour forming capabilities. [ABSTRACT FROM AUTHOR]

The aminopeptidase C (PepC) of Lactobacillus helveticus CNRZ32 was purified by anion exchange chromatography from cell free extracts of an E. coli DH5α clone overexpressing the Lactobacillus aminopeptidase. PepC was found to have a tetrameric structure in its native form with subunits of 50 kDa each, a pH optimum of 6.5 and maximum activity at 45 °C. Sulfhydryl-blocking reagents inhibited the enzyme activity whereas reducing or metal chelating reagents had an activating effect on the PepC activity. The PepC hydrolyzed a wide range of p-nitroaniline derivatives, dipeptides and several tripeptides which contained basic amino acids (Arg, Lys), Pro residues, or cheese flavour precursor amino acids (Met, Leu, Phe) at the N-terminal position. The substrate specificity and residual activity of PepC from several lactic acid bacteria, including the PepC described above, were compared at conditions of pH and NaCl present in cheese. [ABSTRACT FROM AUTHOR]

Examines the biological and molecular characterization of a two-peptide lantibiotic produced by Lactococcus lactis IFPL105. Purification of the bacterion; Performance of hybridization experiments; Description of lantibiotics.

An intracellular esterase from Lactobacillus casei subsp. casei IFPL731 was purified 1000-fold by ion exchange chromatography and gel filtration chromatography. The relative molecular mass of the native enzyme was 105 kDa, while the subunit molecular mass was estimated to be 38 kDa. The esterase hydrolysed tributyrin and had a preference for esters of short-chain fatty acids (butyrate, caproate and caprylate), while it did not hydrolyse palmitate and sterate esters. The apparent Michaelis-Menten constant of the enzyme on p -nitrophenyl butyrate was 0·3 mmol l-1 while on p -nitrophenyl caprylate, it was 0·04 mmol l-1 . The esterase was active over a broad range of pH and temperature values, and retained about 50% of maximal activity at pH 5·0 and 12 °C. Activity was strongly inhibited by 5 mmol l-1 phenylmethylsulphonyl fluoride, β-mercaptoethanol and N -ethylmaleimide, and was stimulated by Zn2+ at 1 mmol l-1 . [ABSTRACT FROM AUTHOR]

Lactococcin A production in lactococci has recently been linked to a signal-sequence-independent secretory system consisting of a four-gene cluster. Lactococcus lactis subsp. lactis LLM23L-A1 has been obtained after Tn 5 mutagenesis of pLLM23, a plasmid containing the gene cluster responsible for lactococcin A production. In contrast to other Tn 5-generated mutants, strain LLM23L-A1 exhibited a 12-fold increase in lactococcin A production. Overproduction of lactococcin A was not linked to an increased pLLM23 copy number. Restriction-enzyme analysis indicated the site of Tn 5 insertion to be at the 3′ end of lcnD and upstream of the lcnA structural gene. From DNA sequencing, the Tn 5 insertion was located −79 bp upstream of the transcription start site of the lcnA and lciA genes, eliminating eight amino acids from the C-terminal end of lactococcin D. Northern blots revealed overproduction of a 500-base transcript in strain LLM23L-A1, which corresponded to that predicted from the positions of the lactococcin A operon transcriptional start site and the termination structures. This result suggests that the overproduction of lactococcin A in strain LLM23L-A1 is at the transcriptional level and provides further impetus for elucidating the complete regulatory mechanism for lactococcin A expression. [ABSTRACT FROM AUTHOR]

Cites a study examined the effects of various types of animal milk on the characteristics of cheeses, in an effort to optimize the process for making low fat cheeses using ultrafiltration. Information in the ultrafiltration process; Microbiological analyses of the cheeses; Details on the texture of the cheeses; Results of the study.