The objective of this work was on the one hand to assess the antibacterial activity of amines anchored to the external surface of mesoporous silica particles against Listeria monocytogenes in ...comparison with the same dose of free amines as well. It was also our aim to elucidate the mechanism of action of the new antimicrobial device. The suitability of silica nanoparticles to anchor, concentrate and improve the antimicrobial power of polyamines against L. monocytogenes has been demonstrated in a saline solution and in a food matrix. Moreover, through microscope observations it has been possible to determine that the attractive binding forces between the positive amine corona on the surface of nanoparticles and the negatively charged bacteria membrane provoke a disruption of the cell membrane. The surface concentration of amines on the surface of the nanoparticles is so effective that immobilized‐amines were 100 times more effective in killing L. monocytogenes bacteria than the same amount of free polyamines. This novel approach for the creation of antimicrobial nanodevices opens the possibility to put in value the antimicrobial power of natural molecules that have been discarded because of its low antimicrobial power.
Practical Application
Consumers demand for high‐quality products, free from chemical preservatives, with an extended shelf‐life. In this study, a really powerful antimicrobial agent based on a nanomaterial functionalized with a non‐antimicrobial organic molecule was developed as a proof of concept. Following this approach it could be possible to develop a new generation of natural and removable antimicrobials based on their anchoring to functional surfaces for food, agricultural or medical purposes.
Thermophilic Campylobacter spp. are recognized as a major cause of acute bacterial diarrhea in humans, with broiler meat being the most common source of human infection. Antibiotic therapy is usually ...necessary for severe or prolonged infections, especially in immunocompromised populations such as young or elderly individuals. However, different studies have demonstrated a close association between antibiotic use in animal production and antimicrobial resistance (AMR) in humans. In this sense, there is social pressure to reduce antibiotic administration and find adequate alternatives to control the presence of bacterial infections in farms. However, there is a lack of information related to Campylobacter AMR dynamics through the entire production system from breeders to their progeny. It is unknown if resistance genes are a result of adaptation through chromosomal mutation or through horizontal gene transfer, instead of vertical transmission of DNA from the parent to their progeny. Thus, the main objectives of this study were to assess the main AMR rates present in a poultry production system, to study the relationship between Campylobacter AMR profiles from breeders and their progeny, and to study the presence and distribution of antibiotic resistance genes in poultry production. Regarding AMR rates, ciprofloxacin was classified as extremely high, followed by nalidixic acid and tetracyclines that were classified as very high. Moreover, this study demonstrated a relationship between the AMR patterns and genes found from Campylobacter strains isolated in breeders and those present in their progeny.
Pathogenic and spoilage microorganisms can adhere to, and grow on, food surfaces, equipment and processing environments, which results in biofilm structures. Considering the role of biofilm in food ...spoilage and safety, inhibition of biofilm formation by naturally-occurring antimicrobial compounds is expected to be an alternative to traditional sanitisers. This study aimed to evaluate the diversity of the microbiota attached to food contact surfaces in the meat industry in Turkey, and to assess the antimicrobial and antibiofilm properties of essential oil components against presumptive isolated pathogens. To do so, conventional and molecular methods were use to identify isolates. Nine Gram-positive isolates were classified as Listeria grayi, Lactobacillus paracasei and Staphylococcus warneri. Eleven Gram-negative bacteria were identified with species Escherichia coli and Acinetobacter baumannii. Given the potential pathogenicity of the Gram-negative species, their biofilm forming capability was also analysed, which displayed moderate and strong abilities. The antimicrobial and antibiofilm activity of natural antimicrobials was assessed, and resulted in minimum bactericidal concentrations (MBC) ranging from 0.1 to 0.2 mg/mL for carvacrol and thymol, 0.2–0.5 mg/mL for eugenol, and 2–6 mg/mL for vanillin against A. baumannii and E. coli strains. Lastly, monostrain biofilm formation by A. baumannii and E. coli was substantially reduced by essential oil components at their respective MBC. The findings herein indicate the potential application of essential oil components to avoid biofilm growth on food contact surfaces to prevent food contamination and spoilage.
•Gram-negative isolates were classified as moderate/strong biofilm producers.•Essential oil components inhibit A. baumannii and E. coli isolated in meat industry.•Essential oil components have potential to control biofilm in food industry.
The microbial population in the pig’s gastrointestinal tract can be influenced by incorporating fibrous by-products into the diets. This study investigated the impact of including two types of dried ...olive cake (OC) in pigs’ diets on fecal bacterial composition. The correlation between fecal microbiota and growth performance, nutrient digestibility, gut fermentation pattern and slurry gas emissions was also evaluated. Thirty male Pietrain x (Landrace x Large white) pigs (47.9 ± 4.21 kg) were assigned to three groups: a control group (C), a group fed a diet with 20% partially defatted OC (20PDOC), and a group fed a diet with 20% cyclone OC (20COC) for 21 days. Fecal samples collected before and after providing the experimental diets were analyzed for the V3-V4 region of the 16S rRNA gene. Pigs were weighed, and feed intake was recorded throughout the study. Potential ammonia and methane emissions from slurry were measured. No significant differences in alpha diversity indexes were found. The taxonomic analysis revealed that Firmicutes and Bacteroidota phyla were dominant at the phylum level across all groups. Differential abundance analysis using ALDEx showed significant differences among groups for various bacteria at the phylum, genus, and species levels at the end of the experiment. Pigs from 20PDOC and 20COC groups exhibited increased abundances of health-promoting bacteria, such as Plactomycetota at the phylum level and Allisonella and an unidentified genus from the Eggerthellaceae family at the genus level. These changes influenced short-chain fatty acids’ (SCFA) concentration in slurries, leading to greater acetic, butyric, caproic and heptanoic acids in OC-fed groups, especially 20COC pigs. A volatility analysis revealed significant positive correlations ( p < 0.05) between Uncultured_Bacteroidales and Unculured_Selenomonadaceae and energy digestibility. Monoglobus and Desulfovibrio showed a positive significant ( p < 0.05) correlation with total SCFA, indicating a high impact on gut fermentation. However, growth performance parameters and potential gas emission displayed no significant correlations with a specific bacterial genus. In conclusion, our results suggest that OC inclusion into pig diets could positively modulate and contribute to the gut microbiota’s favorable composition and functionality. Also, nutrient digestibility and gut fermentation patterns can be associated with specific microbial populations.
The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by four institutions in Spain that flew on board the
Sunrise
balloon-borne solar observatory in June 2009 for almost six days ...over the Arctic Circle. As a polarimeter, IMaX uses fast polarization modulation (based on the use of two liquid crystal retarders), real-time image accumulation, and dual-beam polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the instrument uses a LiNbO
3
etalon in double pass and a narrow band pre-filter to achieve a spectral resolution of 85 mÅ. IMaX uses the high-Zeeman-sensitive line of Fe
i
at 5250.2 Å and observes all four Stokes parameters at various points inside the spectral line. This allows vector magnetograms, Dopplergrams, and intensity frames to be produced that, after reconstruction, reach spatial resolutions in the 0.15 – 0.18 arcsec range over a 50×50 arcsec field of view. Time cadences vary between 10 and 33 s, although the shortest one only includes longitudinal polarimetry. The spectral line is sampled in various ways depending on the applied observing mode, from just two points inside the line to 11 of them. All observing modes include one extra wavelength point in the nearby continuum. Gauss equivalent sensitivities are 4 G for longitudinal fields and 80 G for transverse fields per wavelength sample. The line-of-sight velocities are estimated with statistical errors of the order of 5 – 40 m s
−1
. The design, calibration, and integration phases of the instrument, together with the implemented data reduction scheme, are described in some detail.
Modern agriculture has boosted the production of food based on the use of pesticides and fertilizers and improved plant varieties. However, the impact of some such technologies is high and not ...sustainable in the long term. Although the importance of rhizospheres in final plant performance, nutrient cycling, and ecosystems is well recognized, there is still a lack of information on the interactions of their main players. In this paper, four accessions of pepper are studied at the rhizosphere and root level under two farming systems: organic and conventional. Variations in soil traits, such as induced respiration, enzymatic activities, microbial counts, and metabolism of nitrogen at the rhizosphere and bulk soil, as well as measures of root morphology and plant production, are presented. The results showed differences for the evaluated traits between organic and conventional management, both at the rhizosphere and bulk soil levels. Organic farming showed higher microbial counts, enzymatic activities, and nitrogen mobilization. Our results also showed how some genotypes, such as Serrano or Piquillo, modified the properties of the rhizospheres in a very genotype-dependent way. This specificity of the soil-plant interaction should be considered for future breeding programs for soil-tailored agriculture.
Salmonella spp. is one of the most important causal agents of food-borne illness in developed countries and its presence in irrigation water poses a risk to public health. Its detection in ...environmental samples is not easy when culture methods are used, and molecular techniques such as PCR or ribosomal rRNA probe hybridization (Fluorescent in situ Hybridization, FISH) are outstanding alternatives.
The aim of this work was to determine the environmental risk due to the presence of Salmonella spp. in wastewater by culture, PCR and FISH. A new specific rDNA probe for Salmonella was designed and its efficiency was compared with the rest of methods Serotype and antibiotic resistance of isolated strains were determined.
Forty-five wastewater samples (collected from two secondary wastewater treatment plants) were analysed. Salmonella strains were isolated in 24 wastewater samples (53%), two of them after disinfection treatment. Twenty-three Salmonella strains exhibited resistance to one or more antimicrobial agent. Analysis of wastewater samples yielded PCR positive results for Salmonella in 28 out of the 45 wastewater samples (62%). FISH analysis allowed for the detection of Salmonella in 27 (60%) samples. By using molecular methods, Salmonella was detected in four samples after disinfection treatment.
These results show the prevalence of Salmonella in reclaimed wastewater even after U.V. disinfection, what is a matter of public health concern, the high rates of resistance to antibiotics and the adequacy of molecular methods for its rapid detection. FISH method, with SA23 probe developed and assayed in this work provides a tool for detecting Salmonella in water within few hours, with a high rate of effectiveness.
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