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Bacteria can repurpose their own bacteriophage viruses (phage) to kill competing bacteria. Phage-derived elements are frequently strain specific in their killing activity, although there is limited evidence that this specificity drives bacterial population dynamics. Here, we identified intact phage and their derived elements in a metapopulation of wild plant-associated Pseudomonas genomes. We discovered that the most abundant viral cluster encodes a phage remnant resembling a phage tail called a tailocin, which bacteria have co-opted to kill bacterial competitors. Each pathogenic Pseudomonas strain carries one of a few distinct tailocin variants that target the variable polysaccharides in the outer membrane of co-occurring pathogenic Pseudomonas strains. Analysis of herbarium samples from the past 170 years revealed that the same tailocin and bacterial receptor variants have persisted in Pseudomonas populations. These results suggest that tailocin genetic diversity can be mined to develop targeted "tailocin cocktails" for microbial control.

Microbes use quorum-sensing systems to respond to ecological and environmental changes. In the oral microbiome, the pathogenic bacterium Streptococcus mutans uses quorum-sensing to control the production of bacteriocins. These antimicrobial peptides kill off ecological competitors and allow S. mutans to dominate the microenvironment of dental plaques and form dental caries. One class of bacteriocins produced by S. mutans, the lantibiotic mutacins, are particularly effective at killing due to their broad spectrum of activity. Despite years of study, the regulatory mechanisms governing production of lantibiotic mutacins I, II, and III in S. mutans have never been elucidated. We identified a distinct class of quorum-sensing system, MutRS, that regulates mutacins and is widespread among the streptococci. We demonstrate that MutRS systems are activated by a short peptide pheromone (Mutacin Stimulating Peptide) and show that MutRS controls production of three separate lantibiotic mutacins in three different strains of S. mutans. Finally, we show that paralogous MutRS systems participate in inter- and intrastrain crosstalk, providing further evidence ofthe interplay between quorum-sensing systems in the oral streptococci. [ABSTRACT FROM AUTHOR]

It is well-known that Enterococcus species produce bacteriocins that have antibacterial activity. However, a comprehensive analysis of the bacteriocin distribution among Enterococcus strains has not been conducted. In this study, we identified the bacteriocin genes from 80 Enterococcus faecalis and 38 Enterococcus faecium strains and investigated their antibacterial activity. In the 80 E. faecalis strains, the cytolysin gene (61.3%), enterolysin A gene (27.5%) and BacL1 gene (45.0%) were identified. In the 38 E. faecium strains, the enterocin A gene (97.4%), enterocin B gene (2.6%), enterocin NKR-5-3B gene (21.0%), bacteriocin T8 gene (36.8%) and BacAS9 gene (23.7%) were identified. The antibacterial activity of all strains was tested against E. faecalis and E. faecium. The strains positive for the cytolysin, enterolysin A, BacL1, bacteriocin T8 or BacAS9 genes presented variable antibacterial activity. Several bacteriocin-positive strains showed antibacterial activity against other enterococcal species, but not against Staphylococcus or Escherichia coli. In addition, the enterolysin A-positive strain showed antibacterial activity against vancomycin-resistant E. faecium, and the bacteriocin T8- or BacAS9-positive strains showed activity against vancomycin-resistant E. faecalis and E. faecium. Our findings suggest that E. faecium and E. faecalis strains that carry different bacteriocin genes may affect the composition of the surrounding bacterial community. [ABSTRACT FROM AUTHOR]

Critical health considerations for both raw and processed meats include addressing bacterial spoilage and ensuring safety. Nitrites and nitrates are widely used in the meat industry to enhance color and flavor and extend shelf life. However, health concerns linked to their use make reducing nitrites and nitrates in meat production a significant challenge with potential benefits for both the food industry and consumer health. This challenge has been addressed with the use of biopreservatives, i.e., substances extracted from natural sources or produced by fermentation that can enhance food quality and safety. In this article, we assess the use of live biopreservatives (LBs), defined here as microorganisms that produce antimicrobial substances that can be used to preserve and extend the shelf life of food. Moreover, the potential synergistic effects of LBs with bacteriophages and biodegradable food packaging for meat is also explored. This innovative combination offers a comprehensive approach to meat preservation, enhancing both microbial control and sustainability. Overall, the inclusion of LBs extends the shelf life of meat products through bacteriostatic mechanisms, whereas bacteriophages offer direct (lytic) action against pathogens. Enhancing meat preservation and safety with mixed microbe-mediated strategies requires deeper empirical and theoretical insights and further revision of laws and ethical considerations. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa significantly induces health-associated infections in a variety of species other than humans. Over the years, the opportunistic pathogen has developed resistance against commonly used antibiotics. Since most P. aeruginosa strains are multi-drug resistant, regular antibiotic treatment of its infections is becoming a dire concern, shifting the global focus towards the development of alternate antimicrobial approaches. Pyocins are one of the most diverse antimicrobial peptide combinations produced by bacteria. They have potent antimicrobial properties, mainly against bacteria from the same phylogenetic group. P. aeruginosa, whether from clinical or environmental origins, produce several different pyocins that show inhibitory activity against other multi-drug-resistant strains of P. aeruginosa. They are, therefore, good candidates for alternate therapeutic antimicrobials because they have a unique mode of action that kills antibiotic-resistant bacteria by attacking their biofilms. Here, we review pseudomonas-derived antimicrobial pyocins with great therapeutic potential against multi-drug-resistant P. aeruginosa. [ABSTRACT FROM AUTHOR]

Lactiplantibacillus plantarum ST01BG, ST07BG, ST10BG, and ST15BG; Latilactobacillus curvatus ST02BG; Lacticaseibacillus paracasei ST04BG; Pediococcus pentosaceus ST05BG; Leuconostoc mesenteroides ST06BG; and Enterococcus faecium ST11BG were isolated from home-made fermented vegetables from Northwest Bulgaria and identified by biochemical, physiological, and biomolecular analyses, including partial 16S rRNA sequencing. The strains were designated as bacteriocin producers and the expressed antimicrobials partially characterized with a focus on their proteinaceous nature, stability to different pH and temperatures. The bacteriocins were effective in inhibiting different strains of Listeria spp., Enterococcus spp. (including vancomycin resistant enterococci) and Staphylococcus spp. These strains can be considered safe, based on the evaluation of hemolytic activity, production of biogenic amines, mucin degradation, antibiotic susceptibility/resistance, and gelatinase enzyme production. Moreover, the strains can be considered potentially beneficial based on their stability and survival under simulated gastrointestinal tract conditions (stomach and duodenum), the production of diacetyl, and specific levels of hydrophobicity. Special attention was given to antioxidant properties (DPPH radical, hydroxyl radical, superoxide anion radical scavenging activity, Fe+2 ion chelating activity, and anti-lipid peroxidation) of the strains. Antioxidant properties were found to be strain specific. The beneficial attributes (antimicrobial and antioxidant) of these cultures to fermented food products may enable the reduction of chemical additives in line with consumers' demand for more natural and chemical-free food commodities. [ABSTRACT FROM AUTHOR]

Bacteriocins are antimicrobial peptides produced by bacteria. This study aimed to in silico analyze the presence of bacteriocin gene clusters (BGCs) among the genomes of 22 commensal Staphylococcus isolates from different origins (environment/human/food/pet/wild animals) previously identified as bacteriocin producers. The resistome and plasmidome were studied in all isolates. Five types of BGC were detected in 18 genomes of the 22 bacteriocin-producing staphylococci included in this study: class I (Lanthipeptides), class II, circular bacteriocins, the non-ribosomal-peptide lugdunin and the thiopeptide micrococcin P1 (MP1). A high frequency of lanthipeptides was detected in this collection: BGC variants of BSA, bacCH91, and epilancin15X were identified in two Staphylococcus aureus and one Staphylococcus warneri isolates from food and wild animals. Moreover, two potentially new lanthipeptide-like BGCs with no identity to database entries were found in Staphylococcus epidermidis and Staphylococcus simulans from food and wild animal, respectively. Interestingly, four isolates (one S. aureus and one Staphylococcus hominis, environmental origin; two Staphylococcus sciuri, food) carried the MP1 BGC with differences to those previously described. On the other hand, seven of the 22 genomes (~32%) lacked known genes related with antibiotic or disinfectant-acquired resistance mechanisms. Moreover, the potential carriage of plasmids was evaluated, and several Rep-proteins were identified (~73% of strains). In conclusion, a wide variety of BGCs has been observed among the 22 genomes, and an interesting relationship between related Staphylococcus species and the type of bacteriocin has been revealed. Therefore, bacteriocin-producing Staphylococcus and especially coagulase-negative staphylococci (CoNS) can be considered good candidates as a source of novel bacteriocins. [ABSTRACT FROM AUTHOR]

AbstractStaphylococcus aureus has developed resistance to most conventional antibiotics and is a causative agent of serious infections. Alternative therapies are urgently needed. Bacteriocins are ribosomally synthesized antimicrobial peptides produced by bacteria, including Escherichia coli (E. coli) and Streptococcus pyogenes (S. pyogenes), and represent a potential solution. While several bacteriocins have shown promise, their synergy with bacteriocins from other bacterial species remains largely unexplored. This work used agar diffusion on Muller-Hinton Agar (MHA) with S. aureus as a test bacterium to evaluate E. coli, S. pyogenes and their combined bacteriocins. The bacteriocins of S. pyogenes showed the maximum antimicrobial activity of zone of inhibition (ZOI), 24.93 mm, compared to that of E. coli bacteriocin, which was 19.28 mm, and that of the combined ones at 100% concentration, 22.6 mm. The combined bacteriocins at 50% concentration showed a reduced activity of 18.35 mm. These observations suggest that the bacteriocins produced by S. pyogenes have higher specificity and activity against S. aureus, making them effective therapeutic agents in the fight against multidrug-resistant infections. [ABSTRACT FROM AUTHOR]

Inflammatory bowel disease (IBD) is one of the most challenging diseases in the 21st century, and more than 10 million people around the world suffer from IBD. Because of the limitations and adverse effects associated with conventional IBD therapies, there has been increased scientific interest in microbial‐derived biomolecules, known as postbiotics. Postbiotics are defined as the preparation of inanimate microorganisms and/or their components that confer a health benefit on the host, comprising inactivated microbial cells, cell fractions, metabolites, etc. Postbiotics have shown potential in enhancing IBD treatment by reducing inflammation, modulating the immune system, stabilizing intestinal flora and maintaining the integrity of intestinal barriers. Consequently, they are considered promising adjunctive therapies for IBD. Recent studies indicate that postbiotics offer distinctive advantages, including spanning clinical (safe origin), technological (easy for storage and transportation) and economic (reduced production costs) dimensions, rendering them suitable for widespread applications in functional food/pharmaceutical. This review offers a comprehensive overview of the definition, classification and applications of postbiotics, with an emphasis on their biological activity in both the prevention and treatment of IBD. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Enterococcus spp. are opportunistic human pathogens colonizing the human gut and a significant reservoir for the continuous adaptation of hospital clones. However, studies on the features of enterococci species co-colonizing healthy individuals are scarce. We investigated the prevalence, antibiotic resistance, and bacteriocin profiles of Enterococcus species in fecal samples from healthy adults in Portugal using culture-based methods, WGS, and bacteriocin inhibition assays. Results were compared with data from a 2001 study in the same region. Enterococcus spp. (n = 315; 24% MDR) were recovered from all volunteers. Enterococcus lactis was the prevalent species (75%), followed by Enterococcus faecalis (65%) and Enterococcus faecium (47%). E. lactis prevalence increased 2.5-fold since 2001. Linezolid resistance genes (optrA/poxtA) were detected in E. faecium and Enterococcus thailandicus isolates, while a vancomycin-variable E. faecium was also identified. Virulence and plasmid profiles were diverse across species, with evidence of exchange of virulence markers and plasmid replicons between E. faecium and E. lactis. Bacteriocin gene repertoires were extensive and species-specific. Higher numbers of bacteriocin genes were associated with stronger inhibition profiles, and 25% of E. faecium and E. lactis isolates were capable of inhibiting relevant VRE clones. This study unveils the co-occurrence and ecological dynamics of Enterococcus species in the healthy human gut, reinforcing its role as a reservoir for key antibiotic resistance genes and potentially pathogenic strains. The shift toward E. lactis prevalence and the detection of linezolid resistance genes in healthy individuals underscore the need for ongoing surveillance of the gut microbiome to guide public health strategies and antibiotic stewardship efforts. [ABSTRACT FROM AUTHOR]

The antimicrobial peptide (AMP) circularized bacteriocin enterocin AS-48 produced by Enterococcus sp. exhibits broad-spectrum antibacterial activity via dimer insertion into the plasma membrane to form membrane pore structures, compromising membrane integrity and leading to bactericidal activity. A specific alpha-helical region of enterocin AS-48 has been shown to be responsible for the membrane-penetrating activity of the peptide. The canon syn-enterocin peptide library, generated using rational design techniques to have ninety-five synthetic peptide variants from the truncated, linearized, membrane-interacting domain of enterocin AS-48, was screened against three clinically relevant fungal strains: Cryptococcus neoformans , Candida albicans , and Candida auris for potential antifungal activity. Twelve peptides exhibited antifungal activity against C. neoformans , and two peptides exhibited activity against C. albicans. The fourteen active antifungal peptides were minimally cytotoxic to an immortalized human keratinocyte cell line (HaCats). Four select peptides were identified with minimum inhibitory concentrations (MICs) below 8 µM against C. neoformans. In 36-hour cell growth tests with these fungicidal peptides, fungicidal peptide no. 32 displayed inhibitory properties comparable to the leading antifungal medication fluconazole against C. neoformans. Screening of peptide no. 32 against a deletion library of C. neoformans mutants revealed that the mechanism of action of peptide no. 32 may relate to multivesicular bodies (MVBs) or polysaccharide capsule targeting. These findings importantly demonstrate that naturally derived AMPs produced by bacteria can be sourced, engineered, and modified to exhibit potent antifungal activity. Our results will contribute to the development of broad treatment alternatives to fungal infections and lend themselves to direct implications for possible treatment options for C. neoformans infections. [ABSTRACT FROM AUTHOR]

Background: Listeria monocytogenes is a Gram-positive bacterium responsible for listeriosis, a serious foodborne disease that can lead to serious health complications. Pregnant women, newborns, the elderly, and patients with weakened immune systems are particularly susceptible to infection. Due to the ability of L. monocytogenes to survive in extreme environmental conditions, such as low temperatures, high salinity, and acidity, this bacterium poses a serious threat to food production plants and is particularly difficult to eliminate from these plants. One of the promising solutions to reduce the presence of this bacterium in food products is bacteriocins as natural control agents. These are substances with antibacterial activity produced by other bacteria, mainly lactic acid bacteria (LAB), which can effectively inhibit the development of pathogens such as L. monocytogenes. The use of bacteriocins in the food industry is beneficial due to their natural origin, specificity of action, and consumer safety. However, the problem of resistance to these substances exists. Results: This review focuses on the mechanisms of bacteriocin resistance, such as modifications of bacteriocin docking receptors, changes in the structure of the cell wall and membrane, and the occurrence of cross-resistance to different bacteriocins. Genetic factors determining these mechanisms and strategies to cope with the problem of resistance are also presented. Conclusions: Research on this issue is crucial for developing effective preventive methods that will enable the safe and long-term use of bacteriocins in food production. [ABSTRACT FROM AUTHOR]

Oral microbiome dysbiosis mediates chronic periodontal disease, gut microbial dysbiosis, and mucosal barrier disfunction that leads to steatohepatitis via the enterohepatic circulation. Improving this dysbiosis towards health may improve liver disease. Treatment with antibiotics and probiotics have been used to modulate the microbial, immunological, and clinical landscape of periodontal disease with some success. The aim of the present investigation was to evaluate the potential for nisin, an antimicrobial peptide produced by Lactococcus lactis, to counteract the periodontitis-associated gut dysbiosis and to modulate the glycolipid-metabolism and inflammation in the liver. Periodontal pathogens, namely Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Fusobacterium nucleatum, were administrated topically onto the oral cavity to establish polymicrobial periodontal disease in mice. In the context of disease, nisin treatment significantly shifted the microbiome towards a new composition, commensurate with health while preventing the harmful inflammation in the small intestine concomitant with decreased villi structural integrity, and heightened hepatic exposure to bacteria and lipid and malondialdehyde accumulation in the liver. Validation with RNA Seq analyses, confirmed the significant infection-related alteration of several genes involved in mitochondrial dysregulation, oxidative phosphorylation, and metal/iron binding and their restitution following nisin treatment. In support of these in vivo findings indicating that periodontopathogens induce gastrointestinal and liver distant organ lesions, human autopsy specimens demonstrated a correlation between tooth loss and severity of liver disease. Nisin's ability to shift the gut and liver microbiome towards a new state commensurate with health while mitigating enteritis, represents a novel approach to treating NAFLD-steatohepatitis-associated periodontal disease.

Spoilage of pasteurized milk is mainly caused by the presence of organisms that either survive pasteurization (psychrotolerant spore-formers) or re-contaminate milk in the processing environment (post-pasteurisation contaminants). Pasteurization of bovine milk by heat treating at 72°C for 15-30 seconds ensures milk quality without impairing its organoleptic and nutritional status and extends shelf life to 12-14 days at refrigeration temperatures. Nisin A is a class I bacteriocin known to inhibit gram positive bacteria and approved by the European Food and Safety Authority as a food preservative. It is commercially available as Nisaplin®, which contains a concentration of 2.5% w/w of nisin. This study examined the effect of Nisaplin® at different concentrations on spoilage of refrigerated commercial whole pasteurized milk over a period of 59 days. At a high concentration of 4 mgml-1, Nisaplin® reduced the total bacterial count below the limit of detection in the milk, and inhibition was visible for at least 14 days at 4°C. Previously isolated milk spoilage bacteria were identified using 16s rRNA gene sequencing and utilised as target indicators for bacteriocin production. Lactobacillus delbrueckii ssp. bulgaricus LMG6901, Microbacterium lacticum, and Pseudomonas aeruginosa were utilised as indicator strains in a screen of milk spoilage organisms for bacteriocin production. This resulted in identifying the putative bacteriocin producer Carnobacterium divergens, a lactic acid bacterium active against L. bulgaricus. The study concludes that Nisaplin® is effective in the reduction of microbial load and its effectiveness could be increased when combined with other preservative methods thus forming an extra hurdle in the milk.

Aflatoxins (AF), which cause diseases in humans and animals, are mycotoxins produced by certain types of fungi. Bacteriocins are natural antimicrobial substances synthesized by bacteria. These substances that are in protein structure, generally have short chain and small molecular weight. According to the classification made by Klaenhammer, especially considering Gram (+) bacteria, bacteriocins are divided into 4 different classes. These are Class I (Class IA, Class IB), Class II (Class IIA, Class IIB, Class IIC, Class IID), Class III and Class IV. Enterocin A, Sakacin A, Lactococcin A can be given as examples of Class II bacteriocins. In this study, we examined the interaction of AFB1 aflatoxin (ligand) and Lactococcin A (protein) bacteriocin, which is in Class II, using Molecular Docking. The results showed that Lactococcin A molecule have the potential to be used for aflatoxin degradation.

Abstract Mastitis, often caused by bacterial infection, is an inflammatory condition affecting the mammary glands. The condition is particularly prevalent in dairy cattle. Current treatment of bovine mastitis heavily relies on the use of antibiotics. To identify alternative solutions to antibiotic use, we evaluated the antimicrobial activity of 14 cathelicidins reported from 10 animal species. In conjunction, we assessed two bacteriocins against the bovine-mastitis causative bacterial panel, consisting of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis, Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus equi. Among the antimicrobial peptides (AMPs), cc-CATH3, ML-CATH, and PD-CATH proved to be highly active (minimum inhibitory concentration of 2–41 μg/mL, 0.2–10.3 μM) against all bacterial strains in the panel and field isolates from milk, with elevated somatic cell counts (≥ 500,000 cells/mL). Of the AMPs tested in this study, ML-CATH presented the highest level of effectiveness in controlling mastitis-associated bacterial strains while also possessing minimal cytotoxicity and functional stability against pH change and a high salt condition. The results of in silico analyses on the biochemical features of 12 helical cathelicidins revealed that the charge of AMPs appears to be a major determinant in killing Gram-negative bacteria. Furthermore, we observed a unique motif, “N(n≥3)-P(n≥1)-N(n≥3)”, from the sequences of PMAP-36, cc-CATH3, ML-CATH, and PD-CATH that exhibits potent antimicrobial activity against a broad spectrum of bacteria compared to others. Our findings support the proposition that AMPs could serve as effective antimicrobial alternatives to conventional antibiotics in treating complex animal diseases caused by microbial infection, such as bovine mastitis.

This review delves into the increasing interest in probiotics and paraprobiotics as a viable alternative to antibiotics in aquaculture, highlighting their potential to enhance fish health and prevent diseases. As the aquaculture industry continues its global expansion, addressing the challenges associated with disease outbreaks in high-density fish populations becomes imperative. The review underscores the promising role of probiotics and paraprobiotics as a sustainable strategy to mitigate these challenges. The diverse positive impacts of various probiotic strains such as Arthrobacter , Bacillus , Lactobacillus , Bifidobacterium , Clostridium , and others emphasize their roles in enhancing growth, resistance to diseases (including bacterial, viral, and parasitic infections), stress reduction, water quality management, and environmental sustainability. Challenges such as stability, host specificity, and regulatory considerations must be addressed to optimize the use of probiotics in aquaculture. Additionally, paraprobiotics, or non-viable microbial cells, present a safer alternative to the criticized antibiotics and even live probiotics in environments where microbial viability poses a risk. These inactivated cells retain the ability to modulate the immune system and improve gut health, offering a promising complementary approach to fish disease prevention. The review advocates for a systematic approach combining research, innovation, and collaboration to effectively integrate probiotics and paraprobiotics into fish farming practices. Furthermore, the mechanisms by which probiotics and paraprobiotics modulate gut microbiota, produce antimicrobial compounds, and strengthen fish's immune system have been elucidated. Moreover, the practical applications of probiotics in fish farming, including optimal administration methods and the challenges and limitations faced by the industry, have been discussed. Emphasis on the importance of continued research to explore new probiotic and paraprobiotic strains and develop innovative delivery systems to ensure the sustainability of aquaculture has been discussed. By enhancing fish health, reducing the need for antibiotics, and improving water quality, probiotics, and paraprobiotics contribute to more sustainable and environmentally responsible aquaculture operations. [ABSTRACT FROM AUTHOR]

The coexistence of various microorganisms in ecosystems establishes a dynamic balance in which various beneficial and antagonistic interactions can be observed. However, the use of intensive agricultural methods in food production can disturb this balance. Therefore, active actions are needed to prevent damage to the ecosystem, which can also harm human health. There is no doubt about the role of beneficial microorganisms, which were studied for several decades (e.g., lactic acid bacteria, spore-forming bacilli, yeasts, bacteriophages, etc.) and, based on the acquired knowledge, utilized to improve the microbiological safety across the food production and consumption chain. These microorganisms have been in practical use for quite some time and many of them are recommended under the concept of sustainable food production. Oysters have always been valued for their gastronomic qualities and were considered a symbol of culinary luxury of the gastronomic heritage. Nowadays, we see a rapid and significant increase in oyster production and consumption. However, because of the specifics of production, distribution, and consumption, the safety of this food product is a sensitive issue that requires more attention and innovative approaches to improve farm-to-fork safety. Selecting specific natural-derived biopreservatives and health-promoting microbial-based approaches can be an attractive option for oyster production. This critical review aims to discuss the principal pathogens associated with oyster farming and realistic alternatives for controlling diseases and improving food safety, including probiotics, antimicrobial peptides, microbial metabolites, vaccines, and bacteriophages. Moreover, this review focuses on the microbiological aspects of oyster culture and evaluates the selection and application of host-specific probiotics and postbiotics. [ABSTRACT FROM AUTHOR]

Fresh meat is highly perishable, presenting challenges in spoilage mitigation and waste reduction globally. Despite the efforts, foodborne outbreaks from meat consumption persist. Biopreservation offers a natural solution to extend shelf life by managing microbial communities. However, challenges include the effective diffusion of bacteriocins through the meat matrix and the potential inhibition of starter cultures by bacteriocins targeting closely related lactic acid bacteria (LAB). LAB, predominant in meat, produce bacteriocins – small, stable peptides with broad antimicrobial properties effective across varying pH and temperature conditions. This review highlights the recent advances in the optimization of bacteriocin use, considering its structure and mode of action. Moreover, the strengths and weaknesses of different techniques for bacteriocin screening, including novel bioengineering methods, are described. Finally, we discuss the advantages and limitations of the modes of application of bacteriocins toward the preservation of fresh, cured, and novel meat products. [ABSTRACT FROM AUTHOR]

Whole-genome sequencing was carried out, and the main characteristics of the genomes of three new strains of L. lactis AM1, MA1, and dlA, isolated from fermented milk and cereal grain products of South Africa and Russia, were established. The dual approach of in vitro and in silico analysis used in this work allowed us to assess more fully the bacteriocinogenic potential and antibiotic resistance of L. lactis strains. It was shown that L. lactis AM1 and dlA had an antagonistic effect against the test cultures of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538. The growth retardation of E. coli and S. aureus after 48 hours of cocultivation was 65–75 and 30–50%, respectively. The L. lactis MA1 strain did not exhibit a significant antagonistic effect; the growth inhibition of E. coli and S. aureus was 13 and 26%, respectively. According to the results of in silico analysis using the BAGELv4.0 service, gene clusters of class IId lactococcin-like bacteriocins were found in the genomes of all three strains. In the genomes of the dlA and AM1 strains, the sactipeptide cluster, a class I bacteriocin, is additionally annotated. In silico analysis of the L. lactis genomes showed the absence of transmissible antibiotic resistance genes, and all three strains showed a phenotype susceptible to the main classes of clinically relevant antibiotics (ampicillin, streptomycin, kanamycin, gentamicin, erythromycin, clindamycin, vancomycin, tetracycline, and chloramphenicol). Taken together, the results provide valuable information about the intraspecific diversity of L. lactis and indicate the promise of using new strains as starter cultures and biopreservatives. [ABSTRACT FROM AUTHOR]

Screening of coagulase-negative staphylococci (CNS) isolated from hospital environmental objects has been conducted to reveal their ability to produce antibacterial compounds. The detection frequency of CNS strains with pronounced antagonistic activity was about 1.4%. The antibacterial activity of individual CNS strains was determined by the release of low-molecular peptide compounds into the environment. The molecular weights of the three isolated peptides were 2985, 2998, and 3004 Da. The Staphylococcus hominis-derived peptide containing an unusual amino acid, methyllanthionine, can be attributed to the class I bacteriocins, the lantibiotics. The antibacterial activity of the isolated peptides has been demonstrated against gram-positive bacteria of various genera phylogenetically unrelated to the peptide producers. [ABSTRACT FROM AUTHOR]

Summary: Bacteriocins are antimicrobial peptides synthesised ribosomally by Gram‐positive or Gram‐negative bacteria to gain a competitive advantage. The majority of bacteriocins are derived from Gram‐positive bacteria, with lactic acid bacteria being the most common source. Because they are considered 'natural', there is currently significant development of bacteriocins for application as food preservative agents. As a preservative agent, bacteriocin activity is highly dependent on purity, down to the amino acid profile and sequence. Therefore, bacteriocin identification is important. Currently, MS is a cutting‐edge tool in bacteriocin identification. This method has high selectivity, sensitivity and resolution. To the best of our knowledge, systematic reviews focusing on the application of MS for bacteriocin identification are currently limited. In light of this, the objective of this study is to provide a comprehensive review and summary of MS technologies in bacteriocin research, with a particular focus on the discovery and characterisation of novel sources of bacteriocin. Additionally, studies related to the discovery of bacteriocins from various sources, their role as antimicrobial agents, and their synthesis are emphasised. Thus, this study presents a comprehensive analysis of the advantages, limitations, and future perspectives of the methods employed. [ABSTRACT FROM AUTHOR]

Dark fermentation in mixed cultures has been extensively studied due to its great potential for sustainable hydrogen production from organic wastes. However, microbial composition, substrate competition, and inhibition by fermentation products can affect hydrogen yield and production rates. Lactic acid bacteria have been identified as the key organisms in this process. On one hand, lactic acid bacteria can efficiently compete for carbohydrate rich substrates, producing lactic acid and secreting bacteriocins that inhibit the growth of hydrogen-producing bacteria, thereby decreasing hydrogen production. On the other hand, due to their metabolic capacity and synergistic interactions with certain hydrogen-producing bacteria, they contribute positively in several ways, for example by providing lactic acid as a substrate for hydrogen generation. Analyzing different perspectives about the role of lactic acid bacteria in hydrogen production by dark fermentation, a literature review was done on this topic. This review article shows a comprehensive view to understand better the role of these bacteria and their influence on the process efficiency, either as competitors or as contributors to hydrogen production by dark fermentation. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes contamination may occur after thermal processing of cooked ham. This study aimed to determine the effective nisin concentration to inhibit the growth of L. monocytogenes. Two batches of ham were prepared by adding 12.5 mg nisin/kg ham at brine injection (assay 1) or tumbling stage (assay 2). Another piece of cooked ham was prepared by adding 32 mg nisin/kg ham at brine injection (assay 3). Afterward, samples of cooked ham were contaminated with L. monocytogenes cocktail (4 log CFU/mL). The results of assays 1 and 2 revealed that this nisin concentration was ineffective in inhibiting L. monocytogenes in ham. The minimum bactericidal concentration test results indicated that each L. monocytogenes strain had a different sensitivity profile and the cocktail had greater resistance. High concentrations of nisin (32 mg/mL) were efficient in controlling the most resistant strains. Statistical analyses were performed using ANOVA and Tukey's test. This higher nisin concentration was effective in controlling the L. monocytogenes cocktail in cooked ham over 10 days. The findings highlight the potential of high nisin concentrations to effectively reduce L. monocytogenes contamination in cooked ham. [ABSTRACT FROM AUTHOR]

Background/Objectives: Antimicrobial-resistant (AMR) pathogens represent a serious threat to public health, particularly in food production systems where antibiotic use remains widespread. As a result, alternative antimicrobial treatments to antibiotics are essential for effectively managing bacterial infections. This study aimed to identify and characterize novel antimicrobial peptides produced by bacteria, known as bacteriocins, as well as to recognize safe bacteriocin-producing strains, sourced from poultry slaughterhouse effluents. Methods: A total of 864 bacterial isolates were collected across eight stages of a poultry slaughter line and screened for antimicrobial activity against Gram-positive and Gram-negative indicator strains. Whole-genome sequencing (WGS) was performed on 12 selected strains, including Enterococcus faecium (6 isolates), Lactococcus lactis (1 isolate), Lactococcus garvieae (1 isolate) and Escherichia coli (4 isolates). The presence of bacteriocin gene clusters (BGC), antibiotic resistance genes (ARG), and virulence factors (VF) was analyzed. The antimicrobial activity of a novel bacteriocin was further evaluated using in vitro cell-free protein synthesis (IV-CFPS). Results: WGS revealed multiple BGCs, including a novel class IId bacteriocin, lactococcin P1A (LcnP1A), in L. lactis SWD9. LcnP1A showed antimicrobial activity against various indicator strains, including Listeria monocytogenes. While most bacteriocin-encoding strains harbored ARGs and VFs, E. faecium SWG6 was notable for its absence of ARGs and minimal VFs, highlighting its potential as a probiotic. Conclusions: These findings underscore the importance of discovering novel bacteriocins and safer bacteriocin producing strains to address antimicrobial resistance in the food chain. Further research would validate the efficacy of both the novel lactococcin P1A bacteriocin and the E. faecium SWG6 isolate for application in processed food and animal production systems. [ABSTRACT FROM AUTHOR]

B acteriocins are proteinaceous substances with a broad range of bioactive characteristics that are produced by various bacteria. However, the limited use of bacteriocin is due to its low yield and short stability. Enterolycin-A, a type of enterocin (bacteriocin produced by Enterococcus), was extracted and purified from the Enterococcus faecium SMAN_Baghdad strain. The objective of this study was to synthesize an enterolycin-A conjugate with selenium nanoparticles to form a novel nanohybrid system that may increase the bioactivity of enterolycin-A and overcome these hurdles. The nanohybrid system was characterized via FTIR, XRD, TEM, SEM, and EDX. The Fourier transform infrared (FTIR) results indicate the presence of biological moieties, and the crystallite size was calculated to be 15.29 nm via X-ray diffraction (XRD). The shape and size of the Se-enterolycin-A nanohybrid were determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX) confirmed the presence of selenium and protein (carbon, sulfur, and nitrogen). As a result, the Se-enterolycin-A nanohybrid showed strong antibacterial activity against MDR bacteria (Staphylococcus aureus, Streptococcus mutans, Pseudomonas aeruginosa, and Acinetobacter baumannii) according to agar well diffusion methods, MIC and MBC measurements, and antibiofilm measurements. In addition, compared with enterolycin-A alone, the Se-enterolycin-A nanohybrid exhibited promising antioxidant activity with the DPPH compound. [ABSTRACT FROM AUTHOR]

Aflatoxins (AF), which cause diseases in humans and animals, are mycotoxins produced by certain types of fungi. Bacteriocins are natural antimicrobial substances synthesized by bacteria. These substances that are in protein structure, generally have short chain and small molecular weight. According to the classification made by Klaenhammer, especially considering Gram (+) bacteria, bacteriocins are divided into 4 different classes. These are Class I (Class IA, Class IB), Class II (Class IIA, Class IIB, Class IIC, Class IID), Class III and Class IV. Enterocin A, Sakacin A, Lactococcin A can be given as examples of Class II bacteriocins. In this study, we examined the interaction of AFB1 aflatoxin (ligand) and Lactococcin A (protein) bacteriocin, which is in Class II, using Molecular Docking. The results showed that Lactococcin A molecule have the potential to be used for aflatoxin degradation. [ABSTRACT FROM AUTHOR]

Bacteriocins produced by lactic acid bacteria (LAB) are promising bioactive peptides. Intriguingly, bacteriocins have health benefits to the host and may be applied safely in the food industry as bio-preservatives or as therapeutic interventions preventing intestinal diseases. In recent years, finding a safe alternative approach to conventional treatments to promote gut health is a scientific hotspot. Therefore, this review aimed to give insight into the promising applications of LAB-bacteriocins in preventing intestinal diseases, such as colonic cancer, Helicobacter pylori infections, multidrug-resistant infection-associated colitis, viral gastroenteritis, inflammatory bowel disease, and obesity disorders. Moreover, we highlighted the recent research on bacteriocins promoting gastrointestinal health. The review also provided insights into the proposed mechanisms, challenges and opportunities, trends and prospects. In addition, a SWOT analysis was conducted on the potential applications. Based on properties, biosafety, and health functions of LAB-bacteriocins, we conclude that the future applications of LAB-bacteriocins are promising in promoting gastrointestinal health. Further in vivo trials are needed to confirm these potential effects of LAB-bacteriocins interventions. [ABSTRACT FROM AUTHOR]

This work aimed to evaluate some of the probiotic features and safety of the bacteriocin-producing Latilactobacillus sakei subsp. sakei 2a. The effect of selected commercial drugs from different generic groups and antibiotics on the growth of Ltb. sakei subsp. sakei 2a was also determined. The presence of virulence factors was determined based on PCR with total DNA from Ltb. sakei subsp. sakei 2a. Good growth of Ltb. sakei subsp. sakei 2a was recorded in MRS broth supplemented with 0.2% or 0.4% oxbile or in MRS broth adjusted to a pH from 5.0–9.0. Auto-aggregation of Ltb. sakei subsp. sakei 2a was 62.59%. Different levels of co-aggregation were recorded between Ltb. sakei subsp. sakei 2a and Enterococcus faecalis ATCC19443, Ltb. sakei ATCC15521 and Listeria monocytogenes ScottA. Growth of Ltb. sakei subsp. sakei 2a was not inhibited by commercial drugs from different generic groups. The inhibitory effect on the growth of Ltb. sakei subsp. sakei 2a was recorded only in the presence of Arotin [selective serotonin reuptake inhibitor antidepressant] Minimal Inhibition Concentration (MIC) 1.0 mg/mL, Atlansil [Antiarrhythmic] MIC 0.625 mg/mL, Diclofenac potassium [non-steroidal anti-inflammatory drug (NSAID)] MIC 2.5 mg/mL and Spidufen [NSAID] MIC 15.0 mg/mL. Only two antibiotics tested in this study, Amoxil and Urotrobel, inhibited the growth of Ltb. sakei subsp. sakei 2a with a MIC of <0.5 mg/mL and 5.0 mg/mL, respectively. However, Ltb. sakei subsp. sakei 2a generated positive PCR results on the DNA level for vanA (vancomycin resistance), hyl (hyaluronidase), esp (enterococcal surface protein), ace (adhesion of collagen) and cilA (cytolisin) and a high virulence profile when examined for the presence of virulence factors. It is important to underline that cytolysis has been described as a virulence and antibacterial factor. [ABSTRACT FROM AUTHOR]

Lactic Acid Bacteria (LAB) have garnered significant attention in the food and beverage industry for their significant roles in enhancing safety, quality, and nutritional value. As starter cultures, probiotics, and bacteriocin producers, LAB contributes to the production of high-quality foods and beverages that meet the growing consumer demand for minimally processed functional and health-promoting food products. Industrial food processing, especially in the fresh produce and beverage sector, is shifting to the use of more natural bioproducts in food production, prioritizing not only preservation but also the enhancement of functional characteristics in the final product. Starter cultures, essential to this approach, are carefully selected for their robust adaptation to the food environment. These cultures, often combined with probiotics, contribute beyond their basic fermentation roles by improving the safety, nutritional value, and health-promoting properties of foods. Thus, their selection is critical in preserving the integrity, quality, and nutrition of foods, especially in fresh produce and fruits and vegetable beverages, which have a dynamic microbiome. In addition to reducing the risk of foodborne illnesses and spoilage through the metabolites, including bacteriocins they produce, the use of LAB in these products can contribute essential amino acids, lactic acids, and other bioproducts that directly impact food quality. As a result, LAB can significantly alter the organoleptic and nutritional quality of foods while extending their shelf life. This review is aimed at highlighting the diverse applications of LAB in enhancing safety, quality, and nutritional value across a range of food products and fermented beverages, with a specific focus on essential metabolites in fruit and vegetable beverages and their critical contributions as starter cultures, probiotics, and bacteriocin producers. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) poses a significant challenge to animal production due to the widespread use of antibiotics. Therefore, there is an urgent need for alternative antimicrobial strategies to effectively manage bacterial infections, protect animal health, and reduce reliance on antibiotics. This study evaluated the use of emerging approaches and procedures for the isolation, identification, and characterization of bacteriocin-producing bacteria and their bacteriocins, sourced from the gastrointestinal tract (GIT) of meat-producing pigs. Out of 2056 isolates screened against Gram-positive and Gram-negative indicator strains, 20 of the most active antimicrobial isolates were subjected to whole genome sequencing (WGS) for the prediction of coding DNA sequences (CDS) and the identification of bacteriocin gene clusters (BGC) and their functions. The use of an in vitro cell-free protein synthesis (IV-CFPS) protocol and the design of an IV-CFPS coupled to a split-intein mediated ligation (IV-CFPS/SIML) procedure made possible the evaluation of the production and antimicrobial activity of described and putatively novel bacteriocins. A colony MALDI-TOF MS procedure assisted in the identification of class I, II, and III lanthipeptides. MALDI-TOF MS and a targeted proteomics, combined with a massive peptide analysis (LC-MS/MS) approach, has proven valuable for the identification and biochemical characterization of previously described and novel bacteriocins encoded by the isolated bacteriocin-producing strains. [ABSTRACT FROM AUTHOR]