Search Results (251)

Tetanus is a life-threatening, vaccine-preventable disease caused by tetanospasmin and tetanolysin, which are potent neurotoxins produced by Clostridium tetani, an anaerobic, spore-forming bacterium. Due to the widespread presence of spores in the environment, the disease cannot be eradicated. However, global tetanus prevention initiatives have contributed to a significant decline in tetanus incidence worldwide. Aiming to present the tetanus trends in Romania, we conducted a retrospective analysis of the tetanus surveillance data. During the study period (2010–2023), 97 cases of tetanus were reported in Romania (median: 6.5; IQR: 5–7) with an average incidence rate of 0.03 per 100,000 inhabitants (95% CI: 0.02–0.04; range: 0.01–0.09). The highest incidence rates were recorded among people aged 1 to 14 years old (0.09 per 100,000 inhabitants, 95% CI: 0.06–0.13; range: 0.00–0.20), male (0.05 per 100,000 inhabitants; 95% CI: 0.03–0.06; range: 0.03–0.12), and from rural areas (0.05 per 100,000 inhabitants; 95% CI: 0.03–0.08; range: 0.01–0.17). A decline in the number of tetanus cases of 7% by year was observed, which is supported by the statistical analysis showing a p-value of 0.005 (IRR: 0.93; 95% CI: 0.88–0.98). However, the same decline in tetanus incidence was not supported by the statistical analysis (IRR: 0.93; 95% CI: 0.44–1.98; p = 0.9). Forty-seven tetanus deaths were recorded, with an average case fatality ratio of 42% (95% CI: 25.62–57.92; range: 0–100), showing a decreasing trend of 9% by year (IRR: 0.91; 95% CI: 0.89–0.93). Although the annual number of tetanus cases in Romania has shown a slight downwards trend, its situation has remained relatively stable, as shown by the tetanus incidence. Moreover, the case fatality rate continues to be high. Therefore, our study emphasizes the importance of achieving high vaccination uptake among children and adolescents, raising awareness of the importance of booster doses in adults, and improving the management of tetanus-prone wounds. Full article

Edible insects are gaining traction worldwide; however, the existing data regarding their microbiological quality remain inadequate. This study investigated the bacterial communities and microbiological quality of five types of frozen edible insects commercially available in Thailand. Amplicon sequencing revealed Firmicutes (Bacillota) and Proteobacteria (Pseudomonadota) as the main phyla across all samples; Bacteroidota was predominant in house crickets, Actinobacteriota in silkworms, and Desulfobacterota was exclusively found in house and mole crickets. Culture-based assays showed total viable counts, lactic acid bacteria, yeasts–molds, and spore-formers ranging from 3.41–6.58, 2.52–7.41, 1.83–5.62, to 2.00–4.70 log CFU·g⁻¹, respectively. In some samples, Enterobacteriaceae and Escherichia coli, key hygiene indicators, reached 5.05 and 2.70 log CFU·g⁻¹, respectively. Among foodborne pathogens, presumptive Bacillus cereus was found to vary from <1.70 to 3.93 log CFU·g⁻¹, while Clostridium perfringens and Staphylococcus aureus were under the quantitation limit, and Salmonella was absent. Overall, the results indicate significant variation in microbial diversity and quality among different insect types. The high levels of microbial hygiene indicators and foodborne pathogens in some samples raised food safety concerns and point to the need to develop or implement production guidelines and microbiological criteria for frozen edible insects to ensure food safety. Full article

Spore-forming Bacilli have been explored due to their potential biotechnological features and applications in human health and functional food research. This study focuses on the genetic and phenotypical characterization of the functional probiotic properties of Bacillus velezensis P45, a strain isolated from fish intestines. B. velezensis P45 exhibited antimicrobial activity against Gram-positive and Gram-negative pathogens and demonstrated strong autoaggregation and biofilm formation properties in vitro. The strain also showed tolerance to gastrointestinal conditions and ability to metabolize and adhere to mucin. In silico analysis confirmed the absence of virulence factors and antibiotic resistance genes, reinforcing its safety as a probiotic candidate. Genome mining revealed the presence of genes related to adhesion, such as fibronectin-binding protein and enolases, and for the synthesis of secondary metabolites, including the antimicrobial lipopeptides fengycin, surfactin, and bacillibactin. In addition, phylogenetic comparison using the yloA (rqcH) gene associated with gut adhesion clustered strain P45 with other probiotic Bacillus and B. velezensis strains, while separating it from pathogenic bacteria. Thus, the strain B. velezensis P45 could be a valuable candidate as a probiotic due to its functional properties and safety. Full article

In the African Sahel, fonio (Digitaria sp.) is a cereal crop that alleviates mid-season hunger before other main crops are harvested. As fonio is valued for its ability to grow under low nutrient and drought conditions, it was hypothesized that it may contain endophytic bacteria that can tolerate such extreme stress. White fonio seeds were obtained from a dry environment (Mali) and a moderate rainfall environment (Guinea). Plants were grown indoors on field soil mixed with sand to mimic Sahelian soils, grown at 30 °C, and exposed to drought, optimal water, and low nitrogen stress conditions. In total, 73 cultured bacteria were classified using full-length 16S rRNA sequencing followed by searching three 16S reference databases. Selected strains were tested in vitro for tolerance to relevant abiotic stresses. Including nine isolates from seeds, the candidate root/shoot endophytes spanned 27 genera and 18–39 top-match species. Several well-known nitrogen-fixing bacteria were cultured, including Ensifer. Leaves were dominated by Bacilli (spore-formers known to withstand dry conditions). There were five root isolates of Variovorax. Leifsonia was isolated from the leaves and showed 100% sequence identity with seed isolates, suggestive of transmission from seed to shoot. In vitro experiments showed that seed isolates, including Leifsonia, survived diverse abiotic stresses relevant to the Sahel. Combined, these results suggest that white fonio hosts stress-tolerant microbiota, and points to Leifsonia as a candidate seed-to-plant transmitted endophyte, pending confirmation by future whole genome sequencing. This microbial collection serves as a starting point for long-term experiments to understand stress tolerance in this under-studied crop. Full article

The spore-forming probiotic Bacillus coagulans JBI-YZ6.3 interacts with the gut epithelium via its secreted metabolites as well as its cell walls, engaging pattern-recognition receptors on the epithelium. We evaluated its effects on human T84 gut epithelial cells using in vitro co-cultures, comparing metabolically active germinated spores to the isolated metabolite fraction and cell wall fraction under unstressed versus inflamed conditions. Germinated spores affected epithelial communication via chemokines interleukin-8, interferon gamma-induced protein-10, and macrophage inflammatory protein-1 alpha and beta after 2 and 24 h of co-culture. Non-linear dose responses confirmed that bacterial density affected the epigenetic state of the epithelial cells. In contrast, the cell wall fraction increased cytokine and chemokine levels under both normal and inflamed conditions, demonstrating that the intact bacterium had anti-inflammatory properties, regulating pro-inflammatory signals from its cell walls. During recovery from mechanical wounding, germinated spores accelerated healing, both in the absence and presence of LPS-induced inflammation; both the metabolite and cell wall fractions contributed to this effect. The release of zonulin, a regulator of tight junction integrity, was reduced by germinated spores after 2 h. These findings suggest that B. coagulans JBI-YZ6.3 modulates epithelial chemokine signaling, supports barrier integrity, and enhances epithelial resilience, highlighting its potential as an efficacious multi-faceted probiotic for gut health. Full article

This study evaluates various strains of soil bacterial for use in the development of new biopreparations. Mesophilic spore-forming bacteria were isolated from cultivated soil and analysed for their enzymatic activity, ability to decompose crop residues, and antagonistic properties towards selected phytopathogens. Notably, this is the first cytotoxicity assessment of soil bacterial metabolites on Spodoptera frugiperda Sf-9 (fall armyworm). Bacillus subtilis, Bacillus licheniformis, Bacillus velezensis, Paenibacillus amylolyticus, and Prestia megaterium demonstrated the highest hydrolytic potential for the degradation of post-harvest residues from maize, winter barley, and triticale. They exhibited antimicrobial activity against at least three of the tested phytopathogens and demonstrated the ability to solubilize phosphorus. Metabolites of B. licheniformis (IC50 = 8.3 mg/mL) and B. subtilis (IC50 = 144.9 mg/mL) were the most cytotoxic against Sf-9. We recommend the use of the tested strains in industrial practice as biocontrol agents, plant growth biostimulants, crop residue decomposition stimulants, and bioinsecticides. Future studies should focus on assessing the efficacy of using these strains under conditions simulating the target use, such as plant microcosms and greenhouses and the impact of these strains on the abundance and biodiversity of native soil microbiota. This research can serve as a model procedure for screening other strains of bacteria for agricultural purposes. Full article

The carbon emissions from the cement industry account for approximately 8% of global carbon emissions, which exerts significant pressure on the environment. In this paper, the microbial-induced calcium carbonate precipitation (MICP) technology was introduced into the carbonization modification research of recycled hardened cement powder (RHCP), and the carbon sequestration performance of RHCP under different pressures was studied. The physicochemical properties of the carbonated products were characterized by microscopic testing methods, and the carbon sequestration mechanism under different pressures was obtained. Subsequently, carbonated RHCP (C-RHCP) was tested as a partial cement substitute for solidified sludge to evaluate its mechanical and durability properties. The results show that when the pressures were 0.3 and 0.5 MPa, the carbon sequestration capacity of RHCP was relatively good, reaching 59.14 and 59.82 g/kg, respectively. Since the carbon sequestration amounts under the two pressures were similar, and considering the energy consumption, in this study, a reaction pressure of 0.3 MPa was selected to prepare C-RHCP. Compared with pure cement, the 28-day unconfined compressive strength (UCS) of the sludge cured with 30% C-RHCP increased by 12.08%. The water stability coefficient of the solidified sludge in the C-RHCP group was greater than 1 after soaking for 7, 14, and 21 days, while the water stability coefficient of the cement group decreased to 0.92 at 14 days. After 20 freeze–thaw cycles, the mass losses of the cement group, the RHCP group, and the C-RHCP group were 31.43%, 38.99%, and 33.09%, respectively. This research not only provides an environmentally friendly strategy for the resource utilization of RHCP but also pioneers a new synergistic model that combines microbial mineralization with the modification of industrial solid waste. It demonstrated significant scientific value and engineering application prospects in reducing carbon emissions in the cement industry and promoted sustainable geotechnical engineering practices based on the “waste–waste” principle. Full article

Untreated olive oil mill wastewater (OOMW) from conventionally farmed olives was used in bread production to create a new functional product. Two types of bread were developed with 50% OOMW (EXP-1) and 100% OOMW (EXP-2) replacing water. Two leavening processes were tested: sourdough inoculum (S) vs. biga-like inoculum (B), with controls (CTR) without OOMW addition. The doughs were monitored throughout the acidification process by measuring pH, total titratable acidity, and the development of key fermentative microorganisms. To assess the hygienic quality during fermentation, plate count techniques were employed. After baking, the breads were evaluated for various quality parameters, including weight loss, specific volume, crumb and crust colors, image analysis, and the presence of spore-forming bacteria. Volatile compounds released from the breads were identified using solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME-GC/MS). Polyphenolic compounds were analyzed via liquid chromatography–mass spectrometry (LC-MS). To assess the functional properties of the final products, the breads were homogenized with synthetic human saliva and subjected to in vitro digestion. OOMW did not significantly affect the growth of yeasts and lactic acid bacteria (LAB) or the acidification process. However, in terms of the specific volume and alveolation, breads from the S process and OOMW had poor quality, while those from the B process had better quality. Experimental breads (EXP_B-1 and EXP_B-2) contained higher levels of alcohols (especially ethanol and isobutyl alcohol), carbonyl compounds (like benzaldehyde), esters (such as ethyl caproate and ethyl caprylate), and terpenes. OOMW introduced phenolic compounds like hydroxytyrosol, coumaric acid, caffeic acid, and trans-hydroxycinnamic acid, which were absent in CTR_B breads. Functionalization of EXP_B-1 and EXP_B-2 breads was demonstrated by a 2.4- and 3.9-fold increase in Trolox equivalents, respectively. However, OOMW did not reduce post-prandial hyper-glycemia, as starch digestibility was similar between CTR_B and EXP_B breads. The sensory analysis, which focused solely on the visual, structural, and olfactory characteristics of the breads, excluding taste testing to prevent potential health risks from residual pesticides, showed a high appreciation for EXP_B-1 and EXP_B-2 breads, scoring higher than CTR_B in the overall assessment. Full article

Recent advances in the production of meat and dairy analogues and plant-based products have introduced new food safety challenges, as these foods are susceptible to contamination by both pathogens and spoilage microorganisms originating from raw materials and processing environments. In addition, plant-based analogues often exhibit physicochemical properties such as high water activity, near-neutral pH, and elevated protein and moisture content that favour the survival and growth of microorganisms, as evidenced by the detection of Salmonella sp., Listeria monocytogenes, and Enterobacteriaceae in commercial products. While extrusion and thermal processing effectively reduce microbial loads, these treatments may not inactivate all spores, including spore-forming bacteria like Bacillus cereus and Clostridium spp. Critical findings seem to highlight that some protein isolates are particularly prone to higher microbial contamination, and that outbreaks linked to pathogens such as Salmonella, L. monocytogenes, and E. coli have already occurred in plant-based analogues in Europe and North America. Here we discuss the microbiology and sources of microbial contamination of these products. In addition, we further discuss the integration of non-thermal technologies and biocontrol methods, such as protective cultures, bacteriocins, and bacteriophages, as promising approaches to enhance food safety while addressing clean-label demands. Full article

Bacillus thuringiensis is widely utilized as a microbial insecticide due to its production of parasporal crystals during the spore-forming stage. However, lower fermentation efficiency coupled with elevated production costs limit its broad application. Low-frequency ultrasound (LFU) has been employed in the fermentation industry to enhance microbial growth and metabolism. In this study, the effect of LFU on the growth of B. thuringiensis HD1 and the yields of parasporal crystals was investigated. The maximum biomass accumulation of Bacillus thuringiensis and parasporal crystal production yield were achieved following low-frequency ultrasonic (LFU) treatment applied during the logarithmic growth phase (18 h of cultivation) under optimized parameters: a frequency of 40 kHz, a power output of 176 W, and an irradiation duration of 45 min. Under optimal conditions, LFU significantly increased the cell membrane permeability and secretory inositol, favoring cell growth and parasporal crystal production. FESEM/CLSM and TEM analyses visually displayed the changes in cell morphology. In addition, the germination rate of spores was increased after LFU treatment, which further confirmed the positive effect of LFU on the growth of B. thuringiensis. Compared to the control, parasporal crystals harvested under LFU exhibited significant modifications in their physicochemical characteristics; the particle size increased, the surface electronegativity intensified, and there was a morphological transition from spherical to cubic geometry. Importantly, the parasporal crystals exhibited strong insecticidal activity against S. zeamais adults, a typical stored-product insect pest, with an LC₅₀ of 10.795 mg/g on day 14 and a Kt₅₀ of 4.855 days at a concentration of 30 mg/g. These findings will provide new insights into the product development and application of B. thuringiensis in the future. Full article

Background: Dysbiosis and antibiotic-associated diarrhea (AAD) are significant concerns in clinical settings. Probiotics, such as Bacillus clausii (O/C, N/R, SIN, T), a spore-forming bacterium resistant to gastrointestinal conditions and most commonly used antibiotics, emerge as a promising approach. We aim to assess the role of B. clausii in preventing AAD in children and adults during antibiotic therapy. Materials and methods: A systematic literature search was conducted across multiple databases, including MEDLINE, EMBASE, Cochrane Library, LILACS, and SciELO, up to May 2024. Studies were included if they involved B. clausii (O/C, N/R, SIN, T) administration during antibiotic treatment and reported AAD-related outcomes. Results: A total of four studies were included in the review. The studies comprised two randomized controlled trials (RCTs), one meta-analysis of RCTs, and one expert consensus. The primary outcome was the effectiveness of B. clausii (O/C, N/R, SIN, T) in reducing the incidence of diarrhea. Results showed a significant reduction in the risk of AAD and gastrointestinal symptoms in patients receiving it at a dosage of 4 × 10⁹ CFU/day for children and 6 × 10⁹ CFU/day for adolescents and adults for up to 14 days. Conclusions: B. clausii (O/C, N/R, SIN, T) appears to be an effective probiotic for preventing AAD in adults and children. It significantly improves gastrointestinal symptoms associated with antibiotic treatment, including diarrhea, nausea, and epigastric pain. Future studies are recommended to further elucidate its effectiveness in diverse populations, especially in low- and middle-income countries. Full article

In the study presented herein, an aerobic, Gram-stain-positive, spore-forming bacterium, designated as WLY-B-L8^T, was isolated from a qu-starter (baobaoqu) cultivation facility used for the production of Wuliangye baijiu in Yibin city (Sichuan province, China). The strain comprised short, rod-shape cells of 1.2–1.9 μm in width and 1.7–4.8 μm in length, arranged singly or in pairs. The isolate was able to grow at temperatures of 20–42 °C (optimum growth at 40 °C), pH 5.0–10.0 (optimum growth at pH 8.0), and in the presence of 0–2% (w/v) NaCl (optimum growth with 1% NaCl). Ribose, xylose, arabinose, mannose, glucose, and galactose constituted the major cell-wall sugars. Moreover, meso-diaminopimelic acid (meso-DAP) constituted the diagnostic amino acid. The main polar lipids of WLY-B-L8^T included diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), unidentified aminolipids (UAL 1–2), an unidentified aminophospholipid (UAPL), an unidentified aminoglycolipid (UAGL), and an unidentified lipid (UL). MK-7 was the predominant menaquinone and iso-C_15:0 (23.00%) was the major fatty acid. Comparisons of the 16S rRNA gene sequence indicated that WLY-B-L8^T was most closely related to Bacillus rhizoplanae JJ-63 DSM 12442^T (98.71%), Bacillus pseudomycoides DSM 12442^T (98.21%), and Bacillus cytotoxicus NVH 391–98^T (98.14%). The average nucleotide identity (ANI) values of strain WLY-B-L8^T and the three type strains mentioned above were 88.24%, 80.57%, and 78.70%. The average amino identity (AAI) values between them were 89.84%, 79.51%, and 80.41%. In addition, the digital DNA–DNA hybridization (dDDH) values between them were 36.70%, 26.10%, and 23.90%. The genomic DNA G+C content was 35.97%. Based on the evidence presented herein, WLY-B-L8^T (CICC 25210^T = JCM 36284^T) exhibits promise as the type strain of a novel species, designated as Bacillus multifaciens sp. nov., that can produce protease (119.38 ± 7.44 U/mL) and volatile flavor components when cultured on raw wheat, such as 2-pipendinone (21.95 ± 1.56 mg/L), phenylethyl alcohol (19.08 ± 0.82 mg/L), hydrocinnamic acid (18.60 ± 0.53 mg/L), and acetoin (7.58 ± 0.11 mg/L). Full article

Clostridioides difficile (CD) is a Gram-positive, spore-forming anaerobic bacterium, usually transmitted through the fecal–oral route, that can result from direct person-to-person contact, exposure to contaminated environmental surfaces, or contact with the hands of colonized healthcare personnel. An increased number of infections, especially healthcare-associated, with this etiology has been observed in most countries. As a spore-forming organism, CD is resistant to alcohol formulations and is a challenge for chemical disinfection. The solution could be the supplementation of traditional disinfection with non-touch techniques, such as UV-C radiation. The adoption of UV-C as a supplementary disinfection method in hospitals has significantly increased since the COVID-19 pandemic. However, there are no current guidelines concerning the use of UV-C disinfection in hospitals. The aim of this study was to evaluate the effectiveness of UV-C irradiation in inactivating Clostridioides difficile from different types of surfaces in hospital settings. The study was based on laboratory tests evaluating the efficacy in eliminating three different C. difficile strains on carriers made of plastic, metal and glass after 10 min exposure to UV-C (wavelength, 253.7 nm). We observed a wide range of reductions in the C. difficile suspensions depending on the density of the carrier contamination, type of carrier, strains and the location of the carrier. The percentage reductions ranged from 0 to 100%, but the best results were observed for glass, with lower initial suspension density and carrier placement on a door frame. Statistically significant differences were only seen in different suspension densities. Our experiment was a continuation of the tests done for non-sporing bacteria and C. auris, and there were some interesting differences in C. difficile reflecting its biology, especially its sensitivity to an aerobic atmosphere during the sample drying. Although the elimination of C. difficile by UV-C radiation was confirmed in our experiment, it was lower than in the case of non-spore-forming bacteria. Thus, this method may be used in healthcare settings (hospitals) for improving environmental safety and preventing C. difficile spreading. Full article

Bacillus cereus is a spore-forming, Gram-positive bacterium that causes foodborne illness and dairy spoilage. This study analyzed B. cereus s.s. isolates from milking environments, raw milk, and dairy products to assess their genotypic and phenotypic traits. From 466 samples, 61 isolates were obtained: 27 from milking environments, 9 from dairy environments, 8 from raw milk, and 17 from dairy products. Genomic sequencing identified genes encoding proteolytic (BC5350, BC0666, BC2984, BC0598, BC5351, BC3383, BC2735), lipolytic (BC4862, BC2141, BC1027, BC4123, BC4345, BC5402, BC5401), and esterase (BC1954, BC4515, BC3413, BC3606) enzymes. Plate assays confirmed enzymatic activities. Proteolytic genes were more prevalent in environmental samples, followed by raw milk and dairy products. Lipolytic genes were most frequent in raw milk, followed by environmental samples and dairy products. Esterase genes were most common in dairy environments. These findings suggest that dairy processing influences the enzymatic profile of B. cereus s.s., potentially impacting food safety and quality in the dairy industry. Understanding the distribution of these genes may help develop strategies to mitigate spoilage and contamination risks in dairy products. Full article

Allicin is a chemically complex bioactive compound synthesized in many varieties of garlic. The wide range of biological properties of allicin provides the basis for its potential use as an alternative to antibiotic growth promoters that are currently prohibited in farm animal breeding. Among the many benefits resulting from the use of allicin in animal breeding, especially poultry, its modulating effect on intestinal microbiota, which includes the anaerobic spore-forming bacteria of the genus Clostridium spp., seems to be important. The material for this study consists of intestinal content collected from the caecums of Japanese quails (Coturnix japonica). Culture methods were used to isolate the strains, and the obtained isolates were identified based on their phenotypic characteristics. In addition, PCR methods were used for the detection of the ntnh gene-encoding non-haemagglutinin component of botulinum neurotoxins (BoNTs), the detection of individual genes responsible for the production of major toxins by Clostridium perfringens, and the amplification of conservative 16S rDNA genes. The 16S rDNA amplicons were subsequently submitted to Sanger sequencing. The obtained sequences were analyzed using the Basic Local Alignment Search Tool (BLAST). The ntnh gene was not found in the genetic material of the isolated strains. Among the isolates suspected of belonging to the Clostridium perfringens species, the plc gene determining the production of the alpha toxin was detected, which justifies the classification of the strains into toxotype A. The Sanger sequencing results confirm the presence of mainly saprophytic species in the studied material. The statistical analysis indicated a statistically significant reduction in the level of Clostridium spp., obtained by the use of an appropriate dose of allicin. The presented research results indicate the significant impact of an appropriate dose of allicin on reducing the occurrence of anaerobic intestinal microbiota, while providing important information on the potential application of this compound in animal production in the future. Full article