Fonticins are phage tail-like bacteriocins produced by the Gram-negative bacterium Pragia fontium from the family Budviciaceae. This bacterium produces contractile-type particles that adsorb on the surface of sensitive bacteria and penetrate the cell wall, probably during contraction, in a way similar to the type VI secretion system. We characterized the pore-forming activity of fonticins using both living cells and in vitro model membranes. Using a potassium leakage assay, we show that fonticins are able to permeabilize sensitive cells. On black lipid membranes, single-pore conductance is about 0.78 nS in 1 M NaCl and appears to be linearly dependent on the increasing molar strength of NaCl solution, which is a property of considerably large pores. In agreement with these findings, fonticins are not ion selective for Na+, K+, and Cl-. Polyethylene glycol 3350 (PEG 3350) molecules of about 3.5 nm in diameter can enter the fonticin pore lumen, whereas the larger molecules cannot pass the pore. The size of fonticin pores was confirmed by transmission electron microscopy. The terminal membrane-piercing complex of the fonticin tube probably creates a selective barrier restricting passage of macromolecules. IMPORTANCE Phage tail-like bacteriocins are now the subject of research as potent antibacterial agents due to their narrow host specificity and single-hit mode of action. In this work, we focused on the structure and mode of action of fonticins. According to some theories, related particles were initially adapted for passage of double-stranded DNA (dsDNA) molecules, but fonticins changed their function during the evolution; they are able to form large pores through the bacterial envelope of Gram-negative bacteria. As various pore-forming proteins are extensively used for nanopore sequencing and stochastic sensing, we decided to investigate the pore-forming properties of fonticin protein complexes on artificial lipid membranes. Our research revealed remarkable structural properties of these particles that may have a potential application as a nanodevice.
Lactobacillus plantarum NMD-17 separated from koumiss could produce a bacteriocin named plantaricin MX against Gram-positive bacteria and Gram-negative bacteria. The bacteriocin synthesis of L. plantarum NMD-17 was remarkably induced in co-cultivation with Lactobacillus reuteri NMD-86 as the increase of cell numbers and AI-2 activity, and the expressions of luxS encoding signal AI-2 synthetase, plnB encoding histidine protein kinase, plnD encoding response regulator, and plnE and plnF encoding structural genes of bacteriocin were significantly upregulated in co-cultivation, showing that the bacteriocin synthesis of L. plantarum NMD-17 in co-cultivation may be regulated by LuxS/AI-2-mediated quorum sensing system. In order to further demonstrate the role of LuxS/AI-2-mediated quorum sensing system in the bacteriocin synthesis of L. plantarum NMD-17, plasmids pUC18 and pMD18-T simple were used as the skeleton to construct the suicide plasmids pUC18-UF-tet-DF and pMD18-T simple-plnB-tet-plnD for luxS and plnB-plnD gene deletion, respectively. luxS and plnB-plnD gene knockout mutants were successfully obtained by homologous recombination. luxS gene knockout mutant lost its AI-2 synthesis ability, suggesting that LuxS protein encoded by luxS gene is key enzyme for AI-2 synthesis. plnB-plnD gene knockout mutant lost the ability to synthesize bacteriocin against Salmonella typhimurium ATCC14028, indicating that plnB-plnD gene was a necessary gene for bacteriocin synthesis of L. plantarum NMD-17. Bacteriocin synthesis, cell numbers, and AI-2 activity of luxS or plnB-plnD gene knockout mutants in co-cultivation with L. reuteri NMD-86 were obviously lower than those of wild-type strain in co-cultivation at 6-9 h (P < 0.01). The results showed that LuxS/AI-2-mediated quorum sensing system played an important role in the bacteriocin synthesis of L. plantarum NMD-17 in co-cultivation.
The beneficial influence of bacteriocin-producing, probiotic, mostly non-autochthonous bacteria has already been reported in various animals. However, their use in horses provides limited information, and results with autochthonous bacteria have not been reported. Therefore, the main objective of this model study was to test the effect of autochthonous, bacteriocin-producing faecal strain Enterococcus faecium EF 412 application in horses. One gram of freeze-dried EF 412 strain (109 CFU/mL for 21 days) was applied to horses in a small feed ball. Clinically healthy horses (12), Slovak warm-blood breed of various ages (5-13 years), were involved in a 35-day-long experiment, also functioning as control for themselves. They were stabled in separate boxes (university property), fed twice a day (hay, whole oats or grazed) with water access ad libitum. Sampling was performed at the start of the experiment, i.e. at days 0/1, 21 (3 weeks of EF 412 application) and at day 35 (2 weeks of EF 412 cessation). EF 412 colonized GIT of horses was 3.54 ± 0.75 CFU/g (log 10) at day 21. The eggs of the nematode Strongylus spp. were not found in horses after EF 412 application, and Eimeria spp. oocysts were similarly not found. The other microbiota were not reduced as evaluated by the use of standard method. Using next-generation sequencing, at phylum level, phyla Bacteroidetes and Firmicutes dominated and at family level, they were Bacteroidales BS11 and S24-7 gut goups and Lentisphaerae. In horses, the increasing tendency in phagocytic activity was noted after EF 412 application. Biochemical parameters were in the physiological range. Total protein value was significantly decreased at day 21 compared with day 0/1 as well as with day 35 (P < 0.05). Cholesterol and triglycerides were influenced (decreased) at day 21 compared with day 0/1 and day 35. Neither nematode eggs Strongylus spp. nor Eimeria spp. oocysts were found in faeces after EF 412 application. Autochthonous, faecal strain E. faecium EF 412 showed promising application potential.
Enterotoxigenic Escherichia coli (ETEC) and Shiga toxin-producing E. coli (STEC) strains are the causative agents of severe foodborne diseases in both humans and animals. In this study, porcine pathogenic E. coli strains (n = 277) as well as porcine commensal strains (n = 188) were tested for their susceptibilities to 34 bacteriocin monoproducers to identify the most suitable bacteriocin types inhibiting porcine pathogens. Under in vitro conditions, the set of pathogenic E. coli strains was found to be significantly more susceptible to the majority of tested bacteriocins than commensal E. coli. Based on the production of bacteriocins with specific activity against pathogens, three potentially probiotic commensal E. coli strains of human origin were selected. These strains were found to be able to outcompete ETEC strains expressing F4 or F18 fimbriae in liquid culture and also decreased the severity and duration of diarrhea in piglets during experimental ETEC infection as well as pathogen numbers on the last day of in vivo experimentation. While the extents of the probiotic effect were different for each strain, the cocktail of all three strains showed the most pronounced beneficial effects, suggesting synergy between the tested E. coli strains. IMPORTANCE Increasing levels of antibiotic resistance among bacteria also increase the need for alternatives to conventional antibiotic treatment. Pathogenic Escherichia coli represents a major diarrheic infectious agent of piglets in their postweaning period; however, available measures to control these infections are limited. This study describes three novel E. coli strains producing antimicrobial compounds (bacteriocins) that actively inhibit a majority of toxigenic E. coli strains. The beneficial effect of three potentially probiotic E. coli strains was demonstrated under both in vitro and in vivo conditions. The novel probiotic candidates may be used as prophylaxis during piglets' postweaning period to overcome common infections caused by E. coli.
- MeSH
- bakteriální toxiny * metabolismus MeSH
- bakteriociny metabolismus terapeutické užití MeSH
- Escherichia coli * účinky léků genetika metabolismus MeSH
- faktory virulence genetika MeSH
- feces mikrobiologie MeSH
- infekce vyvolané Escherichia coli mikrobiologie prevence a kontrola veterinární MeSH
- nemoci prasat mikrobiologie prevence a kontrola MeSH
- prasata MeSH
- probiotika terapeutické užití MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- randomizované kontrolované studie veterinární MeSH
Here, we report on the biochemical characterization of a new glycosylated bacteriocin (glycocin), ASM1, produced by Lactobacillus plantarum A-1 and analysis of the A-1 bacteriocinogenic genes. ASM1 is 43 amino acids in length with Ser18-O- and Cys43-S-linked N-acetylglucosamine moieties that are essential for its inhibitory activity. Its only close homologue, glycocin F (GccF), has five amino acid substitutions all residing in the flexible C-terminal 'tail' and a lower IC50 (0.9 nm) compared to that of ASM1 (1.5 nm). Asm/gcc genes share the same organization (asmH← →asmABCDE→F), and the asm genes reside on an 11 905-bp plasmid dedicated to ASM1 production. The A-1 genome also harbors a gene encoding a 'rare' bactofencin-type bacteriocin. As more examples of prokaryote S-GlcNAcylation are discovered, the functions of this modification may be understood.
- MeSH
- bakteriální geny genetika MeSH
- bakteriociny chemie genetika metabolismus MeSH
- fylogeneze MeSH
- glykosylace MeSH
- Lactobacillus plantarum chemie genetika MeSH
- novobiocin MeSH
- plazmidy genetika MeSH
- sekvence aminokyselin MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Streptomyces spp. are Gram-positive bacteria well-known for their ability to produce antibiotics and other metabolites, but few studies on bacteriocins produced by these bacteria have been reported. We tested eight Streptomyces strains against different pathogenic bacteria, and selected S. griseus, S. nigrescens, S. bottroprensis, and S. violaceoruber for further study based on their inhibitory effects against bacteria, including human pathogens. S. bottropensis reached its highest activity at 312 h and was higher than the activities of S. violaceoruber and S. nigrescens. The best condition for bacteriocin precipitation was using diammonium sulfate at 50% saturation. Bacteriocins were susceptible to proteinase treatments and stable at high temperature (up to 100 °C). The highest inhibitory activities were observed between pH 5 and 6. Cross-activity assays indicated that each Streptomyces strain produced different bacteriocins. When preparations of S. griseus and S. nigrescens were subjected to SDS-PAGE, bands of inhibition were observed in the gel overlay assay at a position corresponding to ~ 2 and 3 kDa, respectively, suggesting that both strains are potential sources for novel bacteriocins.
- MeSH
- antibakteriální látky izolace a purifikace metabolismus farmakologie MeSH
- bakteriociny genetika izolace a purifikace metabolismus farmakologie MeSH
- druhová specificita MeSH
- koncentrace vodíkových iontů MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- síran amonný chemie MeSH
- stabilita proteinů MeSH
- Streptomyces klasifikace genetika růst a vývoj metabolismus MeSH
- teplota 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
Seventy-eight isolates of lactic acid bacteria from Ukraine and Thailand were screened for bacteriocinogenic activity against indicator strain Lactobacillus sakei subsp. sakei JCM 1157. One isolate showed an antagonistic activity of cell-free supernatant eliminated after the treatment with Proteinase K. Based on 16S rRNA gene sequence, this isolate was identified as Enterococcus italicus. Bacteriocin produced by this strain showed antimicrobial activity against L. sakei subsp. sakei JCM 1157, Brochothrix thermosphacta DSMZ 20171, and Listeria ivanovii subsp. ivanovii DSMZ 20750 in agar well diffusion assay. This bacteriocin was cationic and hydrophobic. The partially purified bacteriocin was thermostable, while heating of cell-free supernatant increased its activity more than twofold. Molecular mass of the partially purified bacteriocin as determined by SDS-PAGE differed from enterocin A and B previously known for E. italicus. Concentrated bacteriocin decreased the level of biofilm formation in L. sakei subsp. sakei JCM 1157 and Pseudomonas aeruginosa PAO1 in 52.5 and 48.0%, respectively (p < 0.05). We suggest that the studied bacteriocin could be a perspective antibiofilm agent in food conservation and medicine.
- MeSH
- antibakteriální látky chemie metabolismus farmakologie MeSH
- bakteriociny chemie metabolismus farmakologie MeSH
- biofilmy účinky léků MeSH
- Brassica mikrobiologie MeSH
- Enterococcus chemie genetika izolace a purifikace metabolismus MeSH
- fermentace MeSH
- hydrofobní a hydrofilní interakce MeSH
- mikrobiální testy citlivosti MeSH
- Pseudomonas aeruginosa účinky léků MeSH
- stabilita léku MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Thajsko MeSH
Microorganisms develop biofilms on indwelling medical devices and are associated with biofilm-related infections, resulting in substantial morbidity and mortality. Therefore, to prevent and control biofilm-associated infections, the present study was designed to assess the anti-biofilm potential of postbiotics derived from probiotic organisms against most prevalent biofilm-forming Pseudomonas aeruginosa PAO1. Eighty lactic acid bacteria isolated from eight neonatal fecal samples possessed antibacterial activity against P. aeruginosa PAO1. Among these, only four lactic acid bacteria produced both bacteriocin and exopolysaccharides but only one isolate was found to maximally attenuate the P. aeruginosa PAO1 biofilm. More specifically, the phenotypic and probiotic characterization showed that the isolated lactic acid bacteria were gram positive, non-motile, and catalase and oxidase negative; tolerated acidic and alkaline pH; has bile salt concentration; showed 53% hydrophobicity; and was found to be non-hemolytic. Phylogenetically, the organism was found to be probiotic Lactobacillus fermentum with accession no. KT998657. Interestingly, pre-coating of a microtiter plate either with bacteriocin or with exopolysaccharides as well as their combination significantly (p < 0.05) reduced the number of viable cells forming biofilms to 41.7% compared with simultaneous coating of postbiotics that had 72.4% biofilm-forming viable cells as observed by flow cytometry and confocal laser scanning microscopy. Therefore, it can be anticipated that postbiotics as the natural biointerventions can be employed as the prophylactic agents for medical devices used to treat gastrointestinal and urinary tract infections.
- MeSH
- antibakteriální látky metabolismus farmakologie MeSH
- bakteriální polysacharidy metabolismus MeSH
- bakteriociny metabolismus farmakologie MeSH
- biofilmy účinky léků MeSH
- feces mikrobiologie MeSH
- kojenec MeSH
- Lactobacillales chemie genetika izolace a purifikace metabolismus MeSH
- lidé MeSH
- mikrobiální testy citlivosti MeSH
- probiotika metabolismus farmakologie MeSH
- Pseudomonas aeruginosa účinky léků genetika fyziologie MeSH
- Check Tag
- kojenec MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
A set of 178 Escherichia coli isolates taken from patients with inflammatory bowel disease (IBD) was analyzed for bacteriocin production and tested for the prevalence of 30 bacteriocin and 22 virulence factor determinants. Additionally, E. coli phylogenetic groups were also determined. Pulsed-field gel electrophoresis (PFGE) was used for exclusion of clonal character of isolates. Results were compared to data from a previously published analysis of 1283 fecal commensal E. coli isolates. The frequency of bacteriocinogenic isolates (66.9%) was significantly higher in IBD E. coli compared to fecal commensal E. coli isolates (54.2%, p < 0.01). In the group of IBD E. coli isolates, a higher prevalence of determinants for group B colicins (i.e., colicins B, D, Ia, Ib, M, and 5/10) (p < 0.01), including a higher prevalence of the colicin B determinant (p < 0.01) was found. Virulence factor determinants encoding fimbriae (fimA, 91.0%; pap, 27.5%), cytotoxic necrotizing factor (cnf1, 11.2%), aerobactin synthesis (aer, 43.3%), and the locus associated with invasivity (ial, 9.0%) were more prevalent in IBD E. coli (p < 0.05 for all five determinants). E. coli isolates from IBD mucosal biopsies were more frequently bacteriocinogenic (84.6%, p < 0.01) compared to fecal IBD isolates and fecal commensal E. coli. PFGE analysis revealed clusters specific for IBD E. coli isolates (n = 11), for fecal isolates (n = 13), and clusters containing both IBD and fecal isolates (n = 10). ExPEC (Extraintestinal Pathogenic E. coli) virulence and colicin determinants appear to be important characteristics of IBD E. coli isolates, especially the E. coli isolates obtained directly from biopsy samples.
- MeSH
- bakteriální toxiny genetika MeSH
- bakteriociny metabolismus MeSH
- Crohnova nemoc mikrobiologie MeSH
- Escherichia coli genetika izolace a purifikace metabolismus MeSH
- extraintestinální patogenní Escherichia coli izolace a purifikace patogenita MeSH
- lidé MeSH
- lyasy oxokyselin genetika MeSH
- proteiny fimbrií genetika MeSH
- proteiny z Escherichia coli genetika MeSH
- pulzní gelová elektroforéza MeSH
- střevní mikroflóra fyziologie MeSH
- ulcerózní kolitida mikrobiologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
