Search Results (56)

The increasing consumer demand for minimally processed foods (MPFs) has highlighted the need for innovative preservation methods that ensure both safety and quality. Among promising biocontrol tools, bacteriophages—viruses that selectively destroy bacteria—have gained significant attention. This review explores the dual role of bacteriophages in the food industry. On one hand, they offer a natural, highly specific, and environmentally friendly means of controlling both pathogenic and spoilage bacteria in MPFs, contributing to improved food safety, extended shelf life, and reduced reliance on antibiotics and chemical preservatives. Their use spans primary production, bio-sanitization, and biopreservation. On the other hand, phages pose significant risks in fermentation-based industries such as dairy, where they can disrupt starter cultures and impair production. This review also examines the regulatory, technological, and safety challenges involved in phage application, including concerns about antibiotic resistance gene transfer, the presence of endotoxins, and scale-up limitations. Ultimately, this paper argues that with proper strain selection and regulation, bacteriophages can become valuable allies in sustainable food systems, despite their potential drawbacks. The application of strictly virulent bacteriophages as part of “green biotechnology” could enhance food quality and improve consumer health safety. By implementing the “farm to fork” strategy, bacteriophages may contribute to the production of health-promoting and sustainable food. Full article

Sialidases are gradually entering various areas of human practice—in medicine and pharmacy, as antiviral, antitumor, diagnostic, and vaccine preparations; for the chemoenzymatic synthesis of regioselective sialoglycoconjugates; and for the structural analysis of sialoglycoproteins. Optimizing the synthesis conditions of these commercially important enzymes would be beneficial for enhancing their production and expanding potential applications. Since sialidase producers are often pathogenic microorganisms, the use of saprophytic bacteria could be an alternative to reduce the health risk when working with them. So far, the topic has not been widely discussed. By a single-factor optimization method, the most suitable fermentation conditions for achieving maximum sialidase production by the non-model strain Oerskovia paurometabola O129 were established. The dynamics of enzyme accumulation during the growth phases and the optimal physicochemical parameters for cultivation were determined (30 °C, pH 8.0, agitation at 200 rpm, for 28 h). The addition of various inducers and surfactants to improve enzyme yield was also investigated. The effect of surfactants on bacterial sialidase production was tested for the first time. Maximum enzyme production (98.3 U/mL), representing about a three-fold increase compared to non-optimized conditions, was obtained by culturing the strain under optimal conditions and by the synergistic action of glucomacropeptide and Tween 80. A new, simple, and cost-effective laboratory model for optimizing sialidase production by the saprophytic strain O. paurometabola O129 in submerged fermentation was proposed. Future work may involve scaling up the process and exploring genetic or metabolic enhancements for targeted biomedical and industrial applications. Full article

Fengtang plum, a novel cultivar recently developed in China, has gained huge popularity due to its large fruit size, crisp sweetness, distinctive aroma, and notable resistance to brown rot caused by Monilinia spp. To investigate microbial community dynamics during fruit development, we analyzed samples from three phenological stages: fruit-setting (BSP1), veraison (BSP2), and maturity (BSP3). Our results demonstrated stage-specific microbial succession patterns: alpha diversity indices (observed species, ACE, PD_whole_tree) significantly increased at BSP2/BSP3 versus BSP1, accompanied by diverging Shannon index trends between bacteria (progressive enhancement) and fungi (stage-dependent reduction). Bacterial communities maintained Proteobacteria and Firmicutes dominance while accumulating low-abundance species (18.06–61.84%), whereas Ascomycota constituted the persistent fungal phylum with Trichoderma, reaching 95.91% dominance at BSP3. Community differentiation primarily arose from stage-specific bacteria Ralstonia, Brevundimonas, and Limnobacter, and dominant fungi Trichoderma and Cladosporium. Bacterial metabolic shifts were predicted to transition from basic energy production to complex organic/aromatic compound utilization, contrasting with fungal transitions from pathogen–saprophyte competition to saprophytic dominance. While the enrichment of Lactobacillus and Trichoderma during mid-to-late stages may suggest potential associations with aromatic compound production and fungal pathogen resistance, these hypotheses require validation through targeted metabolomics and pathogen challenge experiments. This study elucidates microbial community succession patterns during Fengtang plum development; notably, functional predictions were inferred from 16S/ITS sequencing data rather than direct metagenomic or metatranscriptomic analyses, thus limiting mechanistic interpretations, though future work integrating multi-omics approaches would strengthen functional insights. 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

Nitrogen (N) enrichment significantly impacts temperate forest ecosystems, but we lack a comprehensive understanding of the responses of root morphological characteristics, soil microbial communities, and soil multifunctionality concurrently to varying degrees of N enrichment, particularly when exceeding a threefold localized N input in temperate forests. Therefore, we selected four forest communities in China’s temperate forests and experimented with localized N addition to the dominant tree species in each forest community through the root bag method (three N addition treatments were set up: N1, fourfold soil total N; N2, sixfold soil total N; and CK, control). The results showed that (1) N enrichment treatments significantly improved soil multifunctionality and modified root morphological characteristics, leading to increases in RD (root diameter) and RTD (root tissue density) but decreases in SRL (specific root length) and SRA (specific root area). (2) N enrichment treatments also substantially changed microbial community composition and functional taxa. The relative abundance of eutrophic bacteria increased, while that of oligotrophic bacteria and saprotrophic fungi decreased. (3) The microbial α-diversity index decreased, and the microbial co-occurrence networks became less complex and more vulnerable under N enrichment treatments. (4) Soil multifunctionality and the microbial alpha diversity index had a substantial negative correlation. (5) NH₄⁺-N and NO₃⁻-N contents were the key factors affecting microbial dominance phyla, as well as the bacterial Shannon index and the fungal Chao1 index. (6) In addition, soil properties (except NH₄⁺-N and NO₃⁻-N), soil enzyme activities, root morphological characteristics, and the microbial Chao1 index were significantly different among tree species. In summary, N enrichment significantly alters root morphological characteristics and improves soil multifunctionality. Concurrently, it reduced microbial α-diversity, increased the abundance of eutrophic bacteria, and decreased saprophytic fungi, leading to a less complex and more vulnerable microbial community. This study provided important data and insights for a comprehensive study of the repertoire of responses to nitrogen enrichment in temperate forest ecosystems. Full article

Feeding is an elementary human need from which we obtain the energy and nutrients necessary for development and survival. Health heavily depends on food, which can be a means of different microbial hazards when contaminated at any stage of the food chain, compromising food safety and consumer health. Fish are considered widely produced foods (fishing or aquaculture) and are marketed worldwide; they are also a basic element of the human diet because they are a source of proteins and lipids. On the other hand, owing to their chemical properties (neutral pH and water activity), fish are highly susceptible to contamination by saprophytic and pathogenic microorganisms related to spoilage and risk to human health. Among the contaminating microorganisms in fish are bacteria of the genus Klebsiella, which are considered important in human and animal health worldwide due to their opportunistic pathogenicity, resistance to various antimicrobials, and association with numerous infections at the community and hospital levels, where foods such as fish and other products can serve as important sources of transmission. Therefore, this document presents a bibliographic review focused on describing, in a general way, the genus Klebsiella and its relationship with human health, aquatic animal health, and the safety of fish and products, as well as laboratory analysis procedures and identification of control and prevention measures of this biological hazard in fish and products to safeguard public health. Full article

This study aims to characterize the conjunctival flora of patients scheduled for cataract surgery and determine the susceptibility profile of isolated bacteria to several commonly used topical antibiotics. Conjunctival swabs were taken from 44 consecutive patients (25 males, 19 females; mean age of 75.0 ± 12.6 years) who were scheduled for senile cataract surgery at two Italian centers before starting any prophylactic preoperative treatment. Swabs were processed for the detection of the microbial growth and for species identification. Selective culture media were used, and bacteria were identified using the MicroScan Specialty ID Panels (Beckman Coulter^®, Brea, CA, USA). Antimicrobial susceptibility for the following antibiotics (netilmicin, tobramycin, ofloxacin, oxacillin, levofloxacin, moxifloxacin, chloramphenicol, cefuroxime, and azithromycin) were assessed using the Kirby–Bauer disk diffusion method. Susceptibility for oxacillin was useful to identify methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE). Among the swabs analyzed, 61.4% showed only saprophytic flora, 30.7% showed only potential pathogenic flora, and 8.0% showed mixed flora. S. epidermidis (20.5%), S. intermedius (18.2%), and S. aureus (14.8%) were the most frequent isolates; MRSA and MRSE accounted for 8.0% and 6.8% of isolates. Less frequently (9%), Gram-negative bacteria such as Pseudomonas fluorescent, Serratia marcescens, Moraxella lacunata, Morganella morgani, and Stenotrophomonas maltophila were detected. All isolated organisms showed an excellent sensitivity to moxifloxacin and chloramphenicol (range 83–100%, range 67–100%, Gram-positive sensitivity for moxifloxacin and chloramphenicol, respectively; 100% Gram-negative sensitivity for both). A significant percentage of the eyes of candidates for surgery presented potential pathogenic flora alone or in association with saprophytic organisms. Staphylococci were the most frequently isolated bacteria. Tobramycin and Ofloxacin, widely used in the ophthalmic field, are confirmed to have a reduced sensitivity in vitro. Full article

Anaerobic digesters host a variety of microorganisms, and they work together to produce biogas. While bacterial and archaeal communities have been well explored using molecular techniques, fungal community structures remain relatively understudied. The present study aims to investigate the dynamics and potential ecological functions of the predominant fungi in bacteria-bioaugmented anaerobic digesters. Eight different anaerobic digesters that contained chopped water hyacinth and cow dung as feedstock at 2% total solids were respectively inoculated with eight different bacterial strains and digested anaerobically in controlled conditions. The diversity and dynamics of the fungal community of the digesters before and after digestion were monitored using high-throughput sequencing of the fungal ITS2 sub-region of the ribosomal gene. The functional potential of the fungal community was predicted using ecological guild analysis. The dominant fungal phyla were (with relative abundance ≥1%) Ascomycota and Neocallimastigomycota. Ascomycota exhibited over 90% dominance in all treatments after anaerobic digestion (AD). Aspergillus sp. was consistently dominant across treatments during AD, while prominent anaerobic fungal genera Anaeromyces, Cyllamyces, and Caeomyces decreased. Ecological guild analysis at genus level showed that the majority of the identified fungi were saprophytes, and diversity indices indicated decreased richness and diversity after AD, suggesting a negative impact of AD on fungal communities in the anaerobic digesters. The multivariate structure of the fungal communities showed clustering of treatments with similar fungal taxa. The findings from this study provide insights into the fungal ecological guild of different bacteria-bioaugmented anaerobic digesters, highlighting their potentials in bacteria-augmented systems. Identification of an anaerobic fungal group within the phylum Ascomycota, beyond the well-known fungal phylum Neocallimastigomycota, offers a new perspective in optimizing the AD processes in specialized ecosystems. Full article

Background: The mouth and the oropharyngeal system are home to numerous bacterial species that constitute the so-called oral microbiome and play an important role for the integrity of the oral cavity, influencing the overall health of the body, as demonstrated by several studies. The aim of this study was to evaluate the bacterial modulation potential of a toothpaste (bioredoxin) containing curcumin and melatonin. Both substances have anti-inflammatory properties, as documented in several scientific reports. Methods: The in vivo study we present was a single-center, double-blind trial and was conducted in parallel groups. We enlisted 20 volunteers who were randomly assigned to four distinct groups using blinded four different toothpaste preparations: a standard toothpaste indicated as placebo, a toothpaste with curcumin, a toothpaste with melatonin, and a toothpaste with melatonin and curcumin. Results: The samples from the gingival tasks were taken at time 0 and after 8 weeks of toothpaste treatment. By evaluating the DNA content of the most significant periodontal bacteria related to the total bacteria count using quantitative PCR assays, including the saprophyte component of the microbiome, we demonstrated that the Curcumin and Melatonin treatment has a statistically relevant effect on decreasing the level of periodontal pathogenic bacteria DNA. The toothpaste with the addition of curcumin and melatonin showed a modulation between t0 and t1 of the Campylobacter rectus (14,568 vs. 3532.8) and Peptostreptococcus micro (1320.8 vs. 319) bacteria. In addition, a modulation of pathogenic bacteria and saprophytic bacteria was shown. The synergistic action of the two additives would therefore appear to lead to promising results. Conclusions: Despite the fact that additional studies may be necessary in evaluating the effect of the Curcumin/melatonin combination in modulating a proposed therapeutic effect on infections of the oropharyngeal apparatus, in this report, we show for the first time that a combination of curcumin and melatonin supplemented using an oral cosmetic vehicle has the capacity to decrease the level of periodontal pathogenic bacteria, possibly ameliorating health and the physiological conditions in the buccal scenario. Full article

Listeriosis is a dangerous zoonosis caused by bacteria of the genus Listeria, with Listeria monocytogenes (LM) being the most pathogenic species. Listeria monocytogenes has been detected in various animal species and in humans, and its ability to evolve from an environmental saprophyte to a powerful intracellular pathogen is driven by the invasion mechanisms and virulence factors that enable cell invasion, replication and cell-to-cell spread. Key regulatory systems, including positive regulatory factor A (PrfA) and the stress-responsive sigma factor σ^B, control the expression of virulence genes and facilitate invasion of host cells. Listeriosis poses a significant threat to cattle, sheep and goat herds, leading to abortions, septicemia and meningoencephalitis, and ruminants are important reservoirs for Listeria, facilitating transmission to humans. Other Listeria species such as Listeria ivanovii and Listeria innocua can also cause disease in ruminants. Resilience of LM in food processing environments makes it an important foodborne pathogen that is frequently transmitted through contaminated meat and dairy products, with contamination often occurring along the food production chain. In humans, listeriosis primarily affects immunocompromised individuals, pregnant women and the elderly and leads to severe conditions, such as meningitis, septicemia and spontaneous abortion. Possible treatment requires antibiotics that penetrate the blood–brain barrier. Despite the relatively low antimicrobial resistance, multidrug-resistant LM strains have been detected in animals, food and the environment. Controlling and monitoring the disease at the herd level, along with adopting a One Health approach, are crucial to protect human and animal health and to minimize the potential negative impacts on the environment. Full article

At present, the soil of Chinese greenhouses is experiencing severe nitrogen input in the form of fertilizer, which will cause damage to the soil environment and restrict crop growth in the long run. The response of potential functions of microorganisms as drivers of nutrient cycling and material transformation to nitrogen enrichment has rarely been reported in northern vegetable planting systems. Therefore, we set up four cucumber pot experiments with different nitrogen addition rates (0, 258, 516, and 1032 kg N ha⁻¹ yr⁻¹) in the greenhouse. Bacterial and fungal communities were detected by 16S and ITS rRNA gene sequencing, and bacterial and fungal functional groups were predicted using the FAPROTAX and FUNGuild databases. The findings showed that nitrogen addition induced soil acidification (a decrease of 0.25–1.63 units) significantly reduced microbial diversity and changed the community composition of bacteria and fungi. The relative abundance of bacterial functional groups associated with the nitrogen cycle increased significantly when medium and high levels of nitrogen were added. Conversely, the bacterial functional groups involved in the carbon cycle exhibited the opposite pattern. In this study, NO₃⁻ and soil pH were the main factors affecting the soil microbial community and its functional groups. Our results highlight that hydrocarbon degradation and saprophytic fungi may play key roles in yield formation during cucumber cultivation in northern solar greenhouses. In general, adopting a fertilization strategy that ensures low-medium nitrogen availability can contribute to the sustainable progress of facility agriculture. Full article

Zoonotic diseases are caused by viruses, bacteria, fungi and parasites and they comprise about 75% of all emerging infectious diseases. These can be transmitted via the direct (scratches on skin or animal bites) or indirect mode (through environmental shedding of infectious agent by the infected animal) of transmission. Environmental changes, whether in the form of urbanization, industrialization or destruction of wildlife habitats, lead to more human invasion in wildlife areas, subsequently leading to an increased passage of animals towards human dwellings and more exposure to animals, making humans susceptible to these infections. Climate change is another major factor. Global warming and the evolving thermotolerance of fungi, adapting more to human body temperature than their saprophytic nature, is leading to the emergence of humans as new hosts for fungi. The domestication of animals, rising populations, enhanced tourism, migratory populations, intrusions into wildlife, etc., are other known factors. Zoonotic fungal infections have long been neglected and are now gaining due attention. In this review, we briefly discuss the various aspects currently known for zoonotic fungal infections and bring forth the importance of this particular issue to be addressed in a timely manner. Full article

The cluster of genes determining the production of botulinum toxins is an attribute of not only the Clostridium botulinum species. This cluster is also found in other members of the Clostridium genus, such as C. baratii, C. butyricum, and C. sporogenes. The occurrence of a botulinum-like cluster has also been recorded in strains of other genera, i.e., Enterococcus faecium, as well as in a Gram-negative species isolated from freshwater sediments; however, the biological activity of bont-related genes has not been noted. It can be said that the mentioned species have a dual nature. Another species with a dual nature is C. butyricum. This bacterium is a common human and animal gut commensal bacterium and is also frequently found in the environment. Although non-toxigenic strains are currently used as probiotics in Asia, other strains have been implicated in pathological conditions, such as botulism in infants or necrotizing enterocolitis in preterm neonates. Additionally, C. baratii strains are rare opportunistic pathogens associated with botulism intoxication. They have been isolated from food and soil and can be carried asymptomatically or cause botulism outbreaks in animals and humans. In addition to the mentioned clostridia, the other microorganisms considered as non-toxigenic have also been suspected of carrying botulinum cluster Gram-negative bacteria, such as Chryseobacterium piperi isolated from freshwater sediments; however, the biological activity of bont-related genes has not been noted. Additionally, Enterococcus faecium strains have been discovered carrying BoNT-related clusters (BoNT/En). Literature data regarding the heterogeneity of BoNT-producing strains indicate the requirement to reclassify C. botulinum species and other microorganisms able to produce BoNTs or possess botulinum-like gene clusters. This article aims to show the dual nature of Clostridium strains not belonging to the C. botulinum species that are sporadically able to carry bont clusters, which are usually considered saprophytic and even probiotic, and bont-like clusters in microorganisms from other genera. The aim was also to consider the genetic mechanisms of botulinum cluster expression in strains that are considered opportunistic and the microbiological safety aspects associated with their occurrence in the environment. Full article

The objective of this research was to investigate natural products for their potential against pathogenic microorganisms. Sabinene hydrate (SH), a monoterpenoid, is synthesised by numerous different plants as a secondary metabolite. At present, there is a lack of definite investigations regarding the antimicrobial activity of SH itself and its different isomers. The antimicrobial effects of commercially available SH (composed mainly of trans-isomer) were evaluated within a range of concentrations in three types of contact tests: solid and vapor diffusion and the macro-broth dilution method. Moreover, the effects of SH on the rate of linear growth and spore germination were also examined. Ethanolic SH solutions were tested against an array of microorganisms, including blue-stain fungi (Ceratocystis polonica, Ophiostoma bicolor, O. penicillatum), frequently originating from bark beetle galleries; three fungal strains (Musicillium theobromae, Plectosphaerella cucumerina, and Trichoderma sp.) isolated from a sapwood underneath bark beetle galleries (Ips typographus) on spruce (Picea abies) stems; Verticillium fungicola, isolated from diseased I. typographus larvae; two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa); five yeasts (Candida albicans, C. krusei, C. parapsilosis, Saccharomyces cerevisiae, and Rhodotorula muscilaginosa), and two saprophytic fungi (Aspergillus niger and Penicillium notatum). In solid agar disc diffusion tests, Gram-positive bacteria exhibited greater susceptibility to SH than Gram-negative bacteria, followed by yeasts and fungi. The most resistant to SH in both the disc diffusion and broth macro-dilution methods were P. aeruginosa, A. niger, and Trichoderma sp. strains. Blue-stain fungi and fungi isolated from the Picea sapwood were the most resistant among the fungal strains tested. The minimum inhibition concentrations (MICs) generated by SH and determined using a disc volatilization method were dependent on the fungal species and played an important role in the development of microorganism inhibition. The two Gram-positive bacteria, B. subtilis and S. aureus (whose MICs were 0.0312 and 0.0625 mg/mL, respectively), were the organisms most susceptible to SH, followed by the Gram-negative bacterium, E. coli (MIC = 0.125 mg/mL) and two yeasts, C. albicans and C. kruei (MIC was 0.125 mg/mL and 0.25 mg/mL, respectively). C. parapsilosis (MIC = 0.75 mg/mL) was the yeast most resistant to SH. The investigation of antimicrobial properties of plant secondary metabolites is important for the development of a new generation of fungicides. Full article

Various microorganisms, including Mycoplasma spp., have been reported in canine ejaculate. The impact of these microorganisms on semen quality remains unclear. This study included 63 male intact healthy dogs aged 1–8 years. One dog exhibited azoospermia, indicating a relatively low incidence of this condition. Interestingly, 36.5% of the examined dogs tested negative for both aerobic bacteria and mycoplasmas, while 12.7% tested positive for bacterial presence. Additionally, 60.3% of the dogs tested positive for Mycoplasma spp. using PCR, with most carrying 1–2 Mycoplasma species. We found no significant difference in semen characteristics between Mycoplasma-positive and -negative dogs. The detection of Mycoplasma was not significantly linked to the presence of bacteria in semen. All the microorganisms identified were classified as saprophytic flora. Our findings indicate that Mycoplasma spp. is common in canine ejaculate. Semen quality parameters were not correlated with the presence of Mycoplasma spp. in semen. Mycoplasma HRC689 was the most common species. Some dogs exhibited no presence of aerobic bacteria or mycoplasmas in their semen. Our study highlights the common presence of Mycoplasma spp. in canine ejaculate. Semen quality shows no correlation with Mycoplasma presence. Some canine ejaculate is sterile. Our findings suggest the existence of undescribed species of canine mycoplasmas, necessitating advanced diagnostic techniques like NGS for their identification. Full article