From 98 Lactobacillus strains, isolated from Algerian homemade cheeses, 14 (B1-B14) were selected based on their anti-Escherichia coli and anti-Staphylococcus aureus activities. These strains were also tested towards Listeria monocytogenes 161 and Salmonella Typhimurium LT2 and further investigated for their resistance to simulated gastrointestinal digestion, cell surface properties, ability to adhere to HT-29 cells, cholesterol lowering, antioxidant activity, and technological traits. Five isolates (B9, B13, B18, B19, and B38) were active against L. monocytogenes and Salmonella. From them, three isolates, identified as Lactobacillus brevis (B9, B13, and B38) by MALDI-TOF spectrometry and 16S rDNA sequencing, exhibited high tolerance to pancreatic juice, bile salts and acidic juices, high percentages of hydrophobicity (87, 92, and 81%, respectively), auto-aggregation (61, 68, and 72%, respectively), and adherence to HT-29 cells (79, 84, and 74%, respectively), which testify on their potential of colonization of the human intestine. On the other way, the strains B9 and B13 manifested the most relevant antioxidant activity and cholesterol-lowering ability, respectively. L. brevis strains showed low acidifying and good proteolytic activities with noticeable heat tolerance. The results gathered in this study highlighted the richness of Algerian artisanal cheeses on new lactobacilli strains with an excellent probiotic potential and demonstrated that L. brevis, largely used as nonstarter in cheese manufacture, could be exploited also as a probiotic for human use.
- MeSH
- antibióza MeSH
- bakteriální adheze MeSH
- buňky HT-29 MeSH
- Escherichia coli fyziologie MeSH
- Levilactobacillus brevis * izolace a purifikace fyziologie MeSH
- lidé MeSH
- Listeria monocytogenes * fyziologie MeSH
- potravinářská mikrobiologie * MeSH
- probiotika * izolace a purifikace metabolismus MeSH
- RNA ribozomální 16S genetika MeSH
- Staphylococcus aureus fyziologie MeSH
- sýr * mikrobiologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
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
- antibakteriální látky farmakologie MeSH
- antibióza MeSH
- bakteriální adheze MeSH
- bakteriální léková rezistence MeSH
- bakteriociny metabolismus MeSH
- Caco-2 buňky MeSH
- cholesterol metabolismus MeSH
- Enterococcus faecium účinky léků genetika izolace a purifikace metabolismus MeSH
- kolostrum mikrobiologie MeSH
- lidé MeSH
- Listeria monocytogenes fyziologie MeSH
- mateřské mléko mikrobiologie MeSH
- mikrobiální testy citlivosti MeSH
- probiotika * MeSH
- žaludeční šťáva MeSH
- žlučové kyseliny a soli farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The formation of a hardly removable biofilm in food processing and clinical settings calls for a deeper understanding of composition of the matrix that protects the biofilm cells, as the crucial matrix component is extracellular DNA (eDNA), participating in adhesion, aggregation and penetration reduction, yet serving as a horizontal gene transfer reservoir. Therefore, we evaluated eDNA release from the biofilm of two pathogens, Listeria monocytogenes and Staphylococcus aureus, with respect to their origin under different culturing condition. Primarily, the biofilms were observed by confocal laser scanning microscopy (CLSM) under conditions mimicking the food processing environment and human body. The eDNA was quantitatively characterised based on its area by IMARIS. Next, the eDNA content and biofilm formation were quantified by spectrophotometry. Data from both sets of experiments were statistically evaluated. The eDNA release varied between the microorganism, culturing conditions and the origin of strains. Independent of the method used, the clinical strains of S. aureus released more eDNA than the food related strains at 37 °C. eDNA content can be crucial discriminating matrix component between food related and clinical strains. Deeper understanding of the eDNA role in such a phenomenon could facilitate the design of effective strategy for biofilm disruption.
- MeSH
- biofilmy * MeSH
- biologický transport MeSH
- DNA bakterií chemie genetika metabolismus MeSH
- extracelulární prostor mikrobiologie MeSH
- konfokální mikroskopie MeSH
- lidé MeSH
- Listeria monocytogenes chemie genetika fyziologie MeSH
- listeriové infekce mikrobiologie MeSH
- stafylokokové infekce mikrobiologie MeSH
- Staphylococcus aureus chemie genetika fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
A rare case of a severe prosthetic joint infection in a 71-year-old immunocompetent woman is presented. Listeria monocytogenes was identified in two consecutive samples using broad-range PCR and sequencing, whereas cultivation remained negative for the first sample and streptococci of a non-group A streptococci, non-group B streptococci type were detected for the second one. This report demonstrates that the phenotypic approach may lead to misidentification of L. monocytogenes in a routine clinical setting. Molecular methods of pathogen detection might be useful when a rare and/or unexpected micro-organism is present or the sample is collected during antibiotic treatment.
- MeSH
- DNA bakterií analýza MeSH
- fenotyp MeSH
- genotyp MeSH
- infekce spojené s protézou diagnóza mikrobiologie MeSH
- kultivační média MeSH
- lidé MeSH
- Listeria monocytogenes fyziologie genetika izolace a purifikace klasifikace MeSH
- listeriové infekce diagnóza mikrobiologie MeSH
- polymerázová řetězová reakce MeSH
- protézy kolene mikrobiologie MeSH
- sekvenční analýza DNA MeSH
- senioři MeSH
- Check Tag
- lidé MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
Microbiological risk assessment series, ISSN 1726-5274 no. 4
xxvi, 48 s. : tab., grafy ; 23 cm
- MeSH
- bakteriologie MeSH
- hodnocení rizik metody MeSH
- kontaminace potravin MeSH
- Listeria monocytogenes patogenita fyziologie MeSH
- listeriové infekce MeSH
- manipulace s potravinami MeSH
- Konspekt
- Mikrobiologie
- NLK Obory
- bakteriologie
- zemědělství a potravinářství
- mikrobiologie, lékařská mikrobiologie
- NLK Publikační typ
- publikace WHO
