Search Results (86)

The purpose of current study was the green synthesis of bioactive silver nanoparticles (AgNPs) using Brevibacillus sp. MAHUQ-41 and the exploration of their role in controlling drug-resistant bacterial pathogens Listeria monocytogenes and Yersinia enterocolitica. The culture supernatant of strain MAHUQ-41 was employed for a simple and eco-friendly synthesis of biofunctional silver nanoparticles (AgNPs). The resulting nanoparticles were analyzed using several techniques, including UV–Visible spectroscopy, XRD, FE-TEM, FTIR, and DLS. The UV–Vis spectral analysis of the AgNPs synthesized via Brevibacillus sp. MAHUQ-41 revealed a prominent absorption peak at 400 nm. FE-TEM results confirmed spherical-shaped 15–60 nm sized nanoparticles. XRD results indicated that the synthesized AgNPs were crystalline in nature. The FTIR spectrum determined various functional groups on the surface of synthesized nanoparticles. Potent antibacterial properties were observed in green-synthesized AgNPs against tested pathogens. The MIC value of extracellular synthesized AgNPs for both pathogenic bacteria was 6.2 µg/mL, and the MBCs were 25.0 µg/mL and 12.5 µg/mL for L. monocytogenes and Y. enterocolitica, respectively. Treatment by synthesized AgNPs resulted in morphological alterations and structural damages in both L. monocytogenes and Y. enterocolitica. These alterations can interfere with regular cellular activities, potentially resulting in cell death. This study is the first to report the antimicrobial properties of silver nanoparticles synthesized using Brevibacillus sp. MAHUQ-41. The findings obtained in the present study supported the role of Brevibacillus sp. MAHUQ-41-mediated synthesized AgNPs in controlling drug-resistant bacterial pathogens L. monocytogenes and Y. enterocolitica. Full article

Invasive bacterial gastrointestinal infections represent a substantial clinical burden worldwide, contributing to significant morbidity and, in severe cases, mortality. The causative bacterial agents of these infections include Shigella spp., enteroinvasive Escherichia coli, Salmonella spp., Campylobacter jejuni, Yersinia enterocolitica, and Listeria monocytogenes. Given the growing challenges of therapy failures and rising antibiotic resistance, there is still an unmet need to identify novel, effective, and safe compounds exhibiting antimicrobial, anti-inflammatory, and immunomodulatory activities. In the present review, we aimed to compile current data regarding three alkaloids—berberine, sanguinarine, and cheleritrin—which hold significant promise in treating bacterial invasive gastrointestinal diseases. Our review extended beyond the direct antimicrobial properties of these compounds against pathogens capable of breaching the intestinal epithelial barrier. We also presented their modulatory effects on intestinal barrier integrity and their influence on the composition and function of the resident gut microbiota, thereby highlighting their potential indirect role in attenuating pathogen invasion and disease progression. Thus, our review presents alkaloids as potential preparations that potentiate the activity of classic anti-infective drugs, as well as substances that, by affecting the microbiome and intestinal mucosa, could be used for inflammatory bowel diseases. Full article

Pathogenic Y. enterocolitica’s contamination of cheeks, tongues, and other pork meats at retail was assessed in 2023, over 9 months. A total of 111 samples of cheeks, 104 of tongues, and 160 of fresh meat were taken at retail from the 13 regions of mainland France. The level of contamination was 16.0%, with a higher contamination in tongues (39.4%), followed by cheeks (16.4%). Only one meat sample was contaminated. Of the 128 isolated strains, 97.6% were of the BT4 biotype. Depending on the method used to check the presence of the plasmid—yadA-PCR, CR-MOX testing, or sequencing—the results were not consistent for some strains, but most of the strains (≥ to 65%) had the virulent plasmid pYV. All the BT4 strains (except two strains) carried the sequence ST18; they were distributed in 54 cgMLST genotypes. The genetic diversity of the strains was very high, whatever the typing method used, including cgMLST, wgMLST, and cgSNP. There was higher contamination in tongues and cheeks, and lower contamination in meat, suggesting that the head deboning step is riskier than the evisceration step for contamination by pathogenic Y. enterocolitica. This pathogen remains a zoonotic agent of public health importance to be monitored in pigs. Full article

Over the past decade, foodborne diseases have become a significant public health concern, affecting millions of people globally. Major pathogens like Salmonella spp., Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus contaminate food and cause several infections. This study investigates the potential of thyme essential oil (Thy-EO) as a natural antimicrobial agent against most common and re-emerging foodborne bacteria, including S. enterica, Yersinia enterocolitica, and L. monocytogenes. Preliminary tests provided qualitative evidence of Thy-EO’s efficacy by evaluating its antibacterial activity through direct contact and vapor phase exposure. Then, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were defined to quantitatively evaluate the bacteriostatic and bactericidal effects of Thy-EO, revealing a strong inhibitory effect against S. enterica, Y. enterocolitica and L. monocytogenes. Additionally, Thy-EO exerted rapid bactericidal kinetics characterized by the disruption of bacterial cell membrane integrity over time. Results highlight Thy-EO’s potential as an alternative antimicrobial agent, demonstrating that treatment with Thy-EO significantly and irreversibly affects the growth of the tested foodborne pathogens. Full article

This prospective pilot study examined the association between microorganisms and knee osteoarthritis by identifying pathogens in the synovial membrane, synovial fluid, and blood samples from two patients with primary bilateral knee osteoarthritis, using metagenomic next-generation sequencing (mNGS). Intraoperatively, during routine knee arthroplasty procedures, we collected the following 12 samples from each patient: two synovial membrane samples, two synovial fluid samples, and two venous blood samples. After DNA isolation and library construction, each sample was subjected to deep whole-genome sequencing using the DNBSEQT17 platform with the read length PE150 as the default. Metagenomic sequencing data were mapped to the NCBI NT database to determine species abundance. The predominant species in all samples tested were classified under the Enterobacterales order, the most abundant being Yersinia enterocolitica. The second and third most common microorganisms detected were Escherichia coli and autotrophic, Gram-negative bacteria Synechococcus sp., which is a bioaerosol component, indicating a risk of inhalation of the toxic metabolites of this latter microorganism. This article provides an initial exploration of mNGS use to study the etiopathogenetic mechanisms of knee osteoarthritis (OA). While our analysis identified bacterial DNA, particularly from Yersinia, further cross-sectional studies in larger populations with and without OA are needed to determine the role of these agents in OA pathogenesis. Full article

The purpose of this study was to isolate, identify, and evaluate the antibacterial and probiotic potential of bacteria from honeydew honey collected in Poland. Isolates (189 colonies from 10 honey samples) were evaluated for their antimicrobial activity against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Yersinia enterocolitica, and then identified by MALDI-TOF-MS. The isolates with the greatest antimicrobial properties were screened for their probiotic potential. The total number of bacteria isolated from honey did not exceed the value of 2.5 × 10² CFU/mL. The Bacillus pumilus/altitudinis, B. licheniformis, and Bacillus cereus groups were the dominant identified bacteria. Almost 16% of the isolates expressed antibacterial potential against three pathogenic bacteria, over 20% against two, while almost 34% of the isolates did not inhibit any. The survival rate of the isolates under gastrointestinal tract conditions was higher after 4 h of exposure to bile salts (>60% survival rate for 66.66% of the isolates), while at pH 2.0, it was lower (>50% survival rate for 44% of the isolates). The most resistant isolate B. pumilus/altitudinis survived at a rate of 77% at low pH and 108% with bile salts. These results confirmed that honeydew honey is a promising reservoir of bacteria that produces metabolites with antimicrobial and probiotic potential. Full article

The viable but non-culturable (VBNC) state is a survival strategy for many foodborne pathogens under adverse conditions. Yersinia enterocolitica (Y. enterocolitica) as a kind of primary foodborne pathogen, and it is crucial to investigate its survival strategies and potential risks in the food chain. In this study, the effectiveness of ultraviolet (UV) irradiation and chlorine treatment in disinfecting the foodborne pathogen Y. enterocolitica was investigated. The results indicated that both UV irradiation and chlorine treatment can induce the VBNC state in Y. enterocolitica. The bacteria completely lost culturability after being treated with 25 mg/L of NaClO for 30 min and a UV dose of 100 mJ/cm². The number of culturable and viable cells were detected using plate counting and a combination of fluorescein and propidium iodide (live/dead cells). Further research found that these VBNC cells exhibited reduced intracellular Adenosine Triphosphate (ATP) levels, and increased levels of reactive oxygen species (ROS) compared to non-induced cells. Morphologically, the cells changed from a rod shape to a shorter, coccobacillary shape with small vacuoles forming at the edges, indicating structural changes. Both condition-induced VBNC-state cells were able to resuscitate in tryptic soy broth (TSB) medium supplemented with Tween 80, sodium pyruvate, and glucose. These findings contribute to a better understanding of the survival mechanisms of Y. enterocolitica in the environment and are of significant importance for the development of effective disinfection strategies. Full article

Proliferative enteropathy is an enteric disease caused by the bacterium Lawsonia intracellularis, which affects several species of domestic and wild animals. The mechanisms underlying the mechanisms employed by L. intracellularis to cause host cell proliferation are poorly understood, mostly because this bacterium is extremely difficult to isolate and propagate in vitro. Comparative genomics methods for searching for genes orthologous to genes known to be associated with pathogenesis allow identification of genes potentially involved in pathogenesis by the pathogen of interest. The goal of this study was to carry out in silico research on L. intracellularis genes orthologous to genes required for intracellular invasion and survival present in other pathogenic bacteria, particularly Brucella abortus, B. melitensis, B. suis, Listeria monocytogenes, Mycobacterium tuberculosis, Mycobacterium avium subspecies paratuberculosis, Salmonella enterica, Yersinia pestis, Y. enterocolitica, and Y. pseudotuberculosis. A total of 127 genes associated with invasion and intracellular survival from five known intracellular bacteria were mapped against the predicted proteomes of all L. intracellularis strains publicly available on GenBank, using the OrthoFinder program. A total of 45 L. intracellularis genes were orthologous to genes associated with pathogenesis of other intracellular bacteria. Genes putatively associated with signal the transduction of chemotaxis and cell motility were identified. Genes related to DNA binding and repair were also identified, with some of them supporting a possible association of bacteria with macrophages or inducing pro-inflammatory responses. The homology-based identification of these genes suggests their potential involvement in the virulence and pathogenicity of L. intracellularis, opening avenues for future research and insights into the molecular mechanisms of Lawsonia-elicited proliferative enteropathy. Full article

Diarrhoea remains an important public health concern, particularly in developing countries, and has become difficult to treat because of antibacterial resistance. The development of synergistic antimicrobial agents appears to be a promising alternative treatment against diarrhoeic infections. In this study, the combined effect of tetracycline together with either nitroxoline, sanguinarine, or zinc pyrithione (representing various classes of plant-based compounds) was evaluated in vitro against selected diarrhoeic bacteria (Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, Shigella flexneri, Vibrio parahaemolyticus, and Yersinia enterocolitica). The chequerboard method in 96-well microtiter plates was used to determine the sum of the fractional inhibitory concentration indices (FICIs). Three independent experiments were performed per combination, each in triplicate. It was observed that the combination of tetracycline with either nitroxoline, sanguinarine, or zinc pyrithione produced synergistic effects against most of the pathogenic bacteria tested, with FICI values ranging from 0.086 to 0.5. Tetracycline–nitroxoline combinations produced the greatest synergistic action against S. flexneri at a FICI value of 0.086. The combinations of the agents tested in this study can thus be used for the development of new anti-diarrhoeic medications. However, studies focusing on their in vivo anti-diarrhoeic activity and safety are required before any consideration for utilization in human medicine. Full article

Higher plants produce secondary metabolites expressing antimicrobial effects as a defense mechanism against opportunistic microorganisms living in close proximity with the plant. Fermentation leads to bioconversion of plant substrates to these bioactive compounds and their subsequent release via breakdown of plant cell walls. Fermented feed products have recently started to become implemented in the pig industry to reduce overall disease pressure and have been found to reduce events such as post-weaning diarrhea. In this study, we investigate the antimicrobial potential of fermented soybean- and rapeseed-based pig feed supplements with and without added seaweed. The antimicrobial effect was tested in a plate well diffusion assay against a range of known human and livestock pathogenic bacteria. Further, we investigate the metabolite profiles based on liquid-chromatography mass-spectrometry (LC-MS) analysis of the fermented products in comparison to their unfermented constituents. We observed a pronounced release of potential antimicrobial secondary metabolites such as benzoic acids when the plant material was fermented, and a significantly increased antimicrobial effect compared to the unfermented controls against several pathogenic bacteria, especially Salmonella enterica Typhimurium, Listeria monocytogenes, Yersinia enterocolitica, and a strain of atopic dermatitis causing Staphylococcus aureus CC1. In conclusion, fermentation significantly enhances the antimicrobial properties of rapeseed, soybean, and seaweed, offering a promising alternative to zinc oxide for controlling pathogens in piglet feed. This effect is attributed to the release of bioactive metabolites effective against pig production-relevant bacteria. Full article

The aim of the study was to evaluate the antimicrobial activity of the extracted plants basil (Ocimum basilicum L.), sage (Salvia officinalis L.), lavender (Lavandula officinalis L.), immortelle (Helichrysum italicum (Roth) G. Don), savory (Satureja montana L.), and rosemary (Salvia rosmarinus Spenn.) against foodborne and clinical pathogens. Dried plants were used in the production of Dalmatian cow’s milk hard cheese at concentrations of 0.5, 1.0, 1.5, and 2% to evaluate the microbiological safety and sensory properties of novel cheeses. The broadest antimicrobial activity was found in rosemary and sage, inhibiting ten indicator pathogens, and the strongest antimicrobial activity was found in immortelle and sage, which showed the widest zones of inhibition. The most sensitive indicators were Staphylococcus species and Yersinia enterocolitica. The supplemented cheeses met the official microbiological criteria and were mycotoxin negative. The surface mycobiota of control and experimental cheeses consisted mainly of Penicillium sollitum, based on the sequence analysis of the beta-tubulin and calmodulin genes. The antifungal effect of the added plants was clearly demonstrated in cheeses with added basil and sage (p < 0.05). Full article

Wildlife can represent a reservoir of zoonotic pathogens and a public health problem. In the present study, we investigated the spread of zoonotic pathogens (Salmonella spp., Yersinia enterocolitica, Listeria monocytogenes, Shiga-toxin-producing Escherichia coli (STEC), and hepatitis E virus (HEV)) considering the presence of virulence and antibiotic resistance genes in game meat from animals hunted in northwest Italy. During two hunting seasons (2020 to 2022), samples of liver and/or muscle tissue were collected from chamois (n = 48), roe deer (n = 26), deer (n = 39), and wild boar (n = 35). Conventional microbiology and biomolecular methods were used for the detection, isolation, and characterization of the investigated pathogens. Two L. monocytogenes serotype IIa strains were isolated from wild boar liver; both presented fosfomycin resistance gene and a total of 22 virulence genes were detected and specified in the text. Eight Y. enterocolitica biotype 1A strains were isolated from chamois (2), wild boar (5), and deer (1) liver samples; all showed streptogramin and beta-lactam resistance genes; the virulence genes found were myfA (8/8 strains), ymoA (8/8), invA (8/8), ystB (8/8), and ail (4/8). Our data underscore the potential role of wildlife as a carrier of zoonotic and antibiotic-resistant pathogens in northwest Italy and a food safety risk for game meat consumers. Full article

The camel milk (CM) industry has witnessed a notable expansion in recent years. This expansion is primarily driven by the rising demand for CM and its fermented products. The perceived health and nutritional benefits of these products are mainly responsible for their increasing popularity. The composition of CM can vary significantly due to various factors, including the breed of the camel, its age, the stage of lactation, region, and season. CM contains several beneficial substances, including antimicrobial agents, such as lactoferrin, lysozyme, immunoglobulin G, lactoperoxidase, and N-acetyl-D-glucosaminidase, which protect it from contamination by spoilage and pathogenic bacteria, and contribute to its longer shelf life compared to bovine milk (BM). Nevertheless, certain harmful bacteria, such as Listeria monocytogenes, Yersinia enterocolitica, and Escherichia coli, have been detected in CM, which is a significant public health concern. Therefore, it is crucial to understand and monitor the microbial profile of CM and follow good manufacturing practices to guarantee its safety and quality. This review article explores various aspects of CM, including the types of beneficial and harmful bacteria present in it, the composition of the milk, its antimicrobial properties, its shelf life, and the production of fermented CM products. Full article

Food-borne pathogens and their toxins cause significant health problems in humans. Formation of biogenic amines (BAs) produced by microbial decarboxylation of amino acids in food is undesirable because it can induce toxic effects in consumers. Therefore, it is crucial to investigate the effects of natural additives with high bioactivity like spice extracts to inhibit the growth of these bacteria and the formation of BAs in food. In the present study, the antibacterial effects of diethyl ether spice (sumac, cumin, black pepper, and red pepper) extracts at doses of 1% (w/v) on Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Klebsiella pneumoniae, Pseudomonas aeruginosa, Campylobacter jejuni, Aeromonas hydrophila, Salmonella Paratyphi A, and Yersinia enterocolitica) food-borne pathogen bacterial strains (FBP) were established. In addition, the accumulation of ammonia (AMN), trimethylamine (TMA), and biogenic amines (BAs) in tyrosine decarboxylase broth (TDB) was investigated by using high performance liquid chromatography (HPLC). Sumac extract exhibited the highest antibacterial potential against all FBPs, followed by cumin and peppers. AMN (570.71 mg/L) and TMA (53.66 mg/L) production were strongly inhibited by sumac extract in the levels of 55.10 mg/L for Y. enterocolitica and 2.76 mg/L for A. hydrophila, respectively. With the exception of S. aureus, black pepper dramatically reduced the synthesis of putrescine, serotonin, dopamine, and agmatine by FBP especially for Gram-negative ones. Furthermore, sumac extracts inhibited histamine and tyramine production by the majority of FBP. This research suggests the application of sumac extracts as natural preservatives for inhibiting the growth of FBPs and limiting the production of AMN, TMA, and BAs. Full article

Yersiniosis is a common zoonotic enteric disease among humans, which has been linked to pigs and contaminated food, especially pork. The epidemiology of yersiniosis is still obscure, and studies on yersiniosis in pets are very scarce. In this study, we performed pheno- and genotypic characterisation of 50 Yersinia strains isolated from pets in Finland between 2012 and 2023. Y. enterocolitica 4/O:3/ST135, the most common type in human yersiniosis, was also the most common type (68%) found in clinical faecal samples in our study. Also, human pathogenic Y. enterocolitica 2/O:9/ST139 and Y. pseudotuberculosis O:1/ST9 and O:1/ST42 strains carrying all essential pathogenic genes were identified. Three Y. enterocolitica 4/O:3/ST9 strains were multi-drug-resistant and two of them were highly related, showing one allelic difference (AD) with core genome multi-locus sequence typing. Non-pathogenic, genotypically highly diverse Y. enterocolitica 1A strains, showing more than 1000 ADs and missing the essential virulence genes, were also recognised in dogs and cats. Our study demonstrates that pets can excrete human pathogenic Yersinia in their faeces and may serve as an infection source for human yersiniosis, especially in families with small children in close contact with their pets. Full article