As potential probiotic traits of human milk-isolated bacteria have increasingly been recognized, this study aimed to evaluate the probiotic properties of bacteriocin-producing Enterococcus faecium strains isolated from human milk and colostrum. Among 118 human milk- and colostrum-isolated lactic cocci, only 29 were identified as Enterococcus. Of these, only four Enterococcus faecium isolates exhibited bacteriocigenic activity against several pathogenic Gram-positive bacteria, including Listeria monocytogenes. These isolates exhibited high acid (up to pH 3.0) and bile tolerance (0.5% oxgall) in simulated gastrointestinal conditions, demonstrating their ability to survive through the upper gastrointestinal tract. All of the E. faecium strains were shown to be sensitive to most of the antibiotics including vancomycin, tetracycline, rifampicin, and erythromycin, while they were resistant to kanamycin and chloramphenicol. None of the strains showed any virulence (gelE, agg2, clyA, clyB, clyM) and antibiotic resistance genes (vanA, vanB, ermB, tetM, and aac(6')-le-aph(2″)-la). In addition, all the strains were able to assimilate cholesterol, ranging between 25.2-64.1% and they exhibited variable adherence (19-36%) to Caco-2 cells. Based on the overall results of this in vitro study, four of the E. faecium strains isolated from human milk and colostrum can be considered as promising probiotic candidates; however, further in vivo evaluations are required.

• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Antibiosis MeSH
• Bacterial Adhesion MeSH
• Drug Resistance, Bacterial MeSH
• Bacteriocins metabolism   MeSH
• Caco-2 Cells MeSH
• Cholesterol metabolism   MeSH
• Enterococcus faecium drug effects   genetics   isolation & purification   metabolism   MeSH
• Colostrum microbiology   MeSH
• Humans MeSH
• Listeria monocytogenes physiology   MeSH
• Milk, Human microbiology   MeSH
• Microbial Sensitivity Tests MeSH
• Probiotics * MeSH
• Gastric Juice MeSH
• Bile Acids and Salts pharmacology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Bacteriocins MeSH
• Cholesterol MeSH
• Bile Acids and Salts MeSH

Before use in practice, it is necessary to precisely identify and characterize a new probiotic candidate. Eight animal lactobacilli and collection strain Lactobacillus reuteri CCM 3625 were studied from the point of saccharide fermentation profiles, bile salt resistance, antibiogram profiles, and influence of bile on sensitivity to antibiotics. Studied lactobacilli differed in their sugar fermentation ability determined by API 50CHL and their identification based on these profiles did not correspond with molecular-biological one in most cases. Survival of strains Lactobacillus murinus C and L. reuteri KO4b was not affected by presence of bile. The resistance of genus Lactobacillus to vancomycin and quinolones (ofloxacin, ciprofloxacin) was confirmed in all strains tested. This study provides the new information about oxgall (0.5 and 1 %) effect on the lactobacilli antibiotic susceptibility. Antibiotic profiles were not noticeably affected, and both bile concentrations tested had comparable impact on the lactobacilli antibiotic sensitivity. Interesting change was noticed in L. murinus C, where the resistance to cephalosporins was reverted to susceptibility. Similarly, susceptibility of L. reuteri E to ceftazidime arose after incubation in both concentration of bile. After influence of 1 % bile, Lactobacillus mucosae D lost its resistance to gentamicin. On the base of gained outcomes, the best probiotic properties manifested L. reuteri KO4b, Lactobacillus plantarum KG4, and L. reuteri E due to their survival in the presence of bile.

• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• Goats MeSH
• Lactobacillus drug effects   isolation & purification   MeSH
• Sheep MeSH
• Probiotics analysis   MeSH
• Drug Tolerance MeSH
• Stomach microbiology   MeSH
• Bile Acids and Salts pharmacology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Bile Acids and Salts MeSH

Lactobacillus species are usually used as starters for the production of fermented products, and some strains are capable of producing antimicrobial substances, such as bacteriocins. Because these characteristics are highly desirable, research are continually being performed for novel Lactobacillus strains with bacteriocinogenic potential for use by food industries. The aim of this study was to characterise the bacteriocinogenic potential and activity of Lactobacillus isolates. From a lactic acid bacteria culture collection obtained from raw milk and cheese, 27 isolates were identified by 16S rDNA as Lactobacillus spp. and selected for the detection of lantibiotics biosynthesis genes, bacteriocin production, antimicrobial spectra, and ideal incubation conditions for bacteriocin production. Based on the obtained results, 21 isolates presented at least one of the three lantibiotics biosynthesis genes (lanB, lanC or lamM), and 23 isolates also produced antimicrobial substances with sensitivity to at least one proteinase, indicating their bacteriocinogenic activity. In general, the isolates had broad inhibitory activity, mainly against Listeria spp. and Staphylococcus spp. strains, and the best antimicrobial performance of the isolates occurred when they were cultivated at 25 °C for 24 or 48 h or at 35 °C for 12 h. The present study identified the bacteriocinogenic potential of Lactobacillus isolates obtained from raw milk and cheese, suggesting their potential use as biopreservatives in foods.

• MeSH
• Anti-Bacterial Agents biosynthesis   MeSH
• Bacteriocins biosynthesis   genetics   MeSH
• Biosynthetic Pathways genetics   MeSH
• DNA, Bacterial chemistry   genetics   MeSH
• Lactobacillus genetics   isolation & purification   metabolism   MeSH
• Microbial Sensitivity Tests MeSH
• Milk microbiology   MeSH
• DNA, Ribosomal chemistry   genetics   MeSH
• RNA, Ribosomal, 16S genetics   MeSH
• Sequence Analysis, DNA MeSH
• Cheese microbiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• Bacteriocins MeSH
• DNA, Bacterial MeSH
• DNA, Ribosomal MeSH
• RNA, Ribosomal, 16S MeSH

The factors of bile tolerance (as one among the fundamental characteristics of probiotic bacteria) were determined in lactococci by using plasmid variants. Bile tolerance of Lactococcus lactis wild-type (WT) strains 527 and N7 (determined by viability counts on bile-containing agar) was equivalent to the corresponding plasmid-free derivatives. In contrast, L. lactis WT strain DRC1 had lower bile tolerance than its plasmid-free derivative DRC1021. Plasmid pDR1-1B, extracted from strain DRC1, was introduced into strain DRC1021 by co-transformation with the vector plasmid pGKV21 as an indicator. Strain DRC121 (DRC1021 harboring pGKV21) had good bile tolerance as did strain DRC1021, while strain DRC13 (DRC1021 harboring both pDR1-1B and pGKV21) did not. Fatty acid (FA) composition was different between strains DRC121 and DRC13. The plasmid pDR1-1B or plasmid profile and FA composition are key factors for bile tolerance of strain DRC1, and therefore changing the plasmid profile might be a way of modulating bile tolerance in lactococci.

• MeSH
• Models, Biological MeSH
• Lactococcus lactis chemistry   drug effects   genetics   physiology   MeSH
• Fatty Acids chemistry   metabolism   MeSH
• Plasmids genetics   metabolism   MeSH
• Bile MeSH
• Bile Acids and Salts pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Fatty Acids MeSH
• Bile Acids and Salts MeSH

A quantitative approach has been proposed to evaluate the competitive inhibition of Escherichia coli and Salmonella typhi by live and heat-inactivated laboratory isolated Lactobacillus sp. on adhesion to monolayer of Caco-2 cells. Three species of Lactobacillus (L. casei, L. acidophilus, L. agilis) isolated from human neonate feces and two commercial probiotic strains (L. casei, L. acidophilus) have been compared for probiotic activity. All lactobacilli were able to attach to the Caco-2 cells, however, the degree of adhesion was bacterial strain-dependent. The adhesion indices of the two commercial probiotic strains were not significantly different from the values obtained for the other two similar fecal strains (p > 0.01). The inhibition of attachment of the pathogenic bacteria by inactivated cells of fecal L. acidophilus was examined and compared to the results of live bacteria. The inhibition pattern was similar for live and heat-inactivated L. acidophilus (p > 0.01). The number of attached pathogenic bacteria to the Caco-2 cells decreased when the number of L. acidophilus increased from 10(6) to 10(9) CFU/mL. The heat-inactivated L. acidophilus displayed similar probiotic activity compared to the live bacteria.

• MeSH
• Bacterial Adhesion * MeSH
• Caco-2 Cells MeSH
• Escherichia coli physiology   MeSH
• Feces microbiology   MeSH
• Lactobacillus isolation & purification   physiology   MeSH
• Humans MeSH
• Infant, Newborn MeSH
• Probiotics isolation & purification   MeSH
• Salmonella typhi physiology   MeSH
• Intestines microbiology   MeSH
• Hot Temperature MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Infant, Newborn MeSH
• Female MeSH
• Publication type
• Journal Article MeSH