Antimicrobial Substances Research Articles

Immunohistochemical Characterization of Langerhans Cells in the Skin of Three Amphibian Species.

The amphibian taxon includes three orders that present different morphological characteristics: Anura, Caudata, and Apoda. Their skin has a crucial role: it acts as an immune organ constituting a physical, chemical, immunological, and microbiological barrier to pathogen insult and conducts essential physiological processes. Amphibians have developed specialized features to protect the vulnerable skin barrier, including a glandular network beneath the skin surface that can produce antimicrobial and toxic substances, thus contributing to the defense against pathogens and predators. This study aims to characterize Langerhans cells in the skin of Lithobates catesbeianus (order: Anura; Shaw, 1802), Amphiuma means (order: Caudata; Garden, 1821), and Typhlonectes natans (order: Apoda; Fischer, 1880) with the following antibodies: Langerin/CD207 (c-type lectin), Major Histocompatibility Complex (MHC)II, and Toll-like receptor (TLR)2 (expressed by different types of DCs). Our results showed Langerhans cells positive for Langerin CD/207 in the epidermis of the three species; moreover, some antigen-presenting cells (APCs) in the connective tissue expressed TLR2 and MHCII. The distribution of the Langerhans cells is very similar in the three amphibians examined, despite their different habitats. A greater knowledge of the amphibian immune system could be useful to better understand the phylogeny of vertebrates and to safeguard amphibians from population declines. Furthermore, the similarities between amphibians' and human skin concerning immunological features may be useful in both biology and translational medicine.

Biofilm Production and Porin Permeability Activity in Clinical Isolates of Ciprofloxacin-Resistant Klebsiella pneumoniae in the Tertiary Hospital in Purwokerto, Indonesia

World Health Organization reports that the current use of ciprofloxacin as a broad-spectrum antibiotic shows a pattern of high bacterial resistance in many countries. Klebsiella pneumoniae is known as a Gram-negative bacterium that most often causes infection and is resistant to antibiotics. This study aimed to find patterns of resistance mechanisms based on biofilm production and porin permeability activity in K. pneumoniae clinical specimens from patients at RSUD Prof. Dr Margono Soekardjo Purwokerto, Indonesia. Several isolates of ciprofloxacin-resistant K. pneumoniae were isolated from clinical specimens of blood, sputum, urine, pus, stool and pleural fluid from August to October 2022. Identification and sensitivity testing of K. pneumoniae to ciprofloxacin were performed using Vitek® 2 Compact. A test for biofilm production is carried out by measuring optical density (OD) with a microplate at a wavelength of 630 nm. The porin permeability activity was determined using the value of the minimum inhibitory concentration (MIC) by the LC-MS spectrophotometry method at a wavelength of 630 nm. The results showed that 72 (47 %) isolates were resistant to ciprofloxacin. Among them, 41.3 % (24/58) of ciprofloxacin-resistant K. pneumoniae were able to produce strong biofilm. Porin permeability is indicated by MIC values of 1, 2 and 4 mg/L with bacterial cell counts of 32×106, 19×106 and 34×106 CFU/mL, respectively. This number decreased from the initial control with a bacterial cell count of 10.15×107 CFU/mL. Analysis of the correlation between the significance of biofilm production and the number of bacterial cells indicated that biofilm formation was related to the number of bacterial cells (R = 0.628, p ≤ 0.05). In conclusion, the resistance mechanism of ciprofloxacin-resistant K. pneumoniae involves biofilm production and decreased porin permeability activity. HIGHLIGHTS Major resistance mechanisms in pneumoniae decreased cell permeability from porin activity and biofilm formation Bacterial outer membrane permeability to antimicrobial substances influences inherent resistance. Bacteria produce biofilm to increase their resistance to antibiotics. Porins are non-specific diffusion transport proteins that play a part in the antibiotic resistance process The evolutionary development in the case of antibiotic resistance has an impact on the emergence of understanding in new perspective patterns on how to overcome health problems related to antibiotic resistance GRAPHICAL ABSTRACT

Antibacterial Mechanisms of Constituents from Galla chinensis Revealed by Experimental and Virtual Screening-Based Studies

Many traditional Chinese medicines (TCMs) have been confirmed to have antibacterial activities. However, very few substances have been found to be active against Gram-negative bacteria. This study aimed to identify antimicrobial activity substances against Gram-negative bacteria from fourteen TCMs. Fourteen TCMs with antibacterial potential were chosen for quantitative extraction and antibacterial activity assay, and the plant with the highest activity against Escherichia coli was selected to construct the component-target network. The following virtual screening and enzyme inhibition experiments were performed to analyse the antibacterial mechanisms of the compounds from Galla chinensis. The chemical constituents of Galla chinensis were identified by chemical fingerprinting. 1, 2, 3, 4, 6-Penta-O-galloyl-β-D-glucose (PGG) from Galla chinensis exhibited significant inhibition activity against adenylyl transferase (ATase) of E. coli and antibacterial activity against E. coli. Meanwhile, PGG was identified in the Galla chinensis ethanol extract as the abundant ingredient with a high content of 1.95% (w/w). PGG enriched in Galla chinensis is a promising natural antibiotic with the mode of action inhibiting ATase activity. To our knowledge, this is the first study attributing the antibacterial activity of PGG to its affinity with ATase.

Effects of Chemical and Biological Fungicide Applications on Sexual Sporulation of Rhizoctonia solani AG-3 TB on Tobacco.

Rhizoctonia solani AG-3 TB primarily causes tobacco target spot disease by producing a large number of sexual spores. However, inducing sexual spore formation under in vitro conditions has been challenging, impeding further research on its control. In this study, field experiments were conducted to assess the effects of different concentrations of chemical and biological fungicides on the production of sexual spores of R. solani AG-3 TB on tobacco plants. The results demonstrated that four chemical fungicides (propiconazole-morpholine guanidine, bordeaux mixture, thiophanate-methyl, and mancozeb) significantly induced sexual spore formation. Among them, increasing the concentrations of the first three fungicides resulted in an increase in the number of sexual spores, while increasing the concentration of mancozeb led to a decrease in spore count. The pathogenic fungus produced more sexual spores during the night than during the day. Temperature, humidity, and light conditions influenced spore production. Additionally, the infection rate of sexual spores was directly proportional to their concentration and inoculation time, but their survival time did not exceed 6 h in vitro. Importantly, Streptomyces rectiolaceus A8 significantly suppressed sexual spore formation, achieving an 83.63% control efficacy in the field and producing antimicrobial substances against R. solani AG-3 TB. In conclusion, appropriate concentrations of chemical fungicides can induce sexual spore formation, while A8 can inhibit their production, showing potential value for controlling tobacco target spot disease.

Antimicrobial Activity of Jatropha Curcas Sap on Selected Microorganisms

Jatropha curcas sap is used for medicinal purposes.It has played a major role in the treatment of various diseases including bacterial and fungal infections.This study evaluated the antimicrobial activity of Jatropha curcas sap against selected microorganisms (Shigella spp, Staphylococcus aureus, Salmonella spp,Candida albicans and Trichophyton spp) using standard procedures.The qualitative phytochemical screening of the sap reveals the presence of saponins, alkaloids, flavonoids,tannins, carbohydrate, glycosides while Steroids was absent. It was observed that the test organisms were more susceptible at high concentration which is 100. The highest zone of inhibition for bacteria was observed on Staphylococcus aureus and the lowest zone of inhibition was on Salmonella sp. For fungi the highest zone of inhibition was on Candida albicans and the lowest zone of inhibition was on Trichophyton sp. There was no zone of inhibition for water which serves as negative control. But there was zone of inhibition for the positive controls which were Ciprofloxacin and Ketoconazole. Jatropha curcas sap is a potential antimicrobial substance, active against Gram negative and Gram-positive bacteria and some fungi. It is therefore a potential antimicrobial agent.

Utilization of Palm Oil Waste into Liquid Smoke in Cellulose Commercial Starch Nano Fiber Composite as Antimicrobial Substances in the Manufacturing of Food Packaging

The high demand for plastic use today will result in environmental damage because the plastic that is widely used cannot be broken down. This plastic waste is dangerous for the sustainability of the food chain, pollutes water and soil, causes global warming, and causes air pollution. This research synthesizes a cellulose nanofiber composite with commercial starch in a 1:1 ratio with the influence of the addition of smoke liquid from palm oil waste. This research aims to process cellulose nanocomposite fibers combined with commercial starch and use them in biodegradable plastic by testing the effect of giving smoke liquid on the development of microbial substances in environmentally friendly biodegradable plastic food packaging. So the resulting product is expected to have the potential to reduce dependence on the use of synthetic plastic. This research aims to determine the optimum concentration of liquid acid from empty oil palm fruit bunches as an antimicrobial agent in the resulting bioplastic. The addition of liquid smoke changes the bioplastic properties of FTIR and XRD the attractive strength of bioplastic. The sample with the highest concentration of liquid smoke had the greatest tensile strength (2.34 MPa). The addition of liquid smoke concentration from empty oil palm shells showed a good inhibitory area for the development of bacillus cereus (10.8 mm).
 Keywords: liquid smoke, plastic biodegradable, food packaging, antimicrobial

More than the sum of its parts: uncovering emerging effects of microbial interactions in complex communities.

Microbial communities are not only shaped by the diversity of microorganisms and their individual metabolic potential, but also by the vast amount of intra- and interspecies interactions that can occur pairwise interactions among microorganisms, we suggest that more attention should be drawn towards the effects on the entire microbiome that emerge from individual interactions between community members. The production of certain metabolites that can be tied to a specific microbe-microbe interaction might subsequently influence the physicochemical parameters of the habitat, stimulate a change in the trophic network of the community or create new micro-habitats through the formation of biofilms, similar to the production of antimicrobial substances which might negatively affect only one microorganism but cause a ripple effect on the abundance of other community members. Here, we argue that combining established as well as innovative laboratory and computational methods is needed to predict novel interactions and assess their secondary effects. Such efforts will enable future microbiome studies to expand our knowledge on the dynamics of complex microbial communities.

PMMA and PVP blended nanofibers with incorporated antimicrobial agent: Spectroscopy and mass spectrometry characterization

Electrospun polymeric nanofibers incorporated with some medicines or biologically active nanoparticles have a huge range of various applications in biomedical fields such as wound dressing, drug delivery, and tissue engineering. Blending several polymers with different properties allows one to obtain a new material with improved physicochemical and mechanical characteristics, as well as to control the incorporation and release of medical agents, including antimicrobial, antifungal, and other substances. In this work, a novel approach to prepare a blend of two polymers [polyvinylpyrrolidone (PVP) and polymethyl methacrylate (PMMA)] to produce biocompatible nanofibers with incorporated antibacterial agents — phenylalanine or silver nanoparticles is proposed. The diameter of the obtained nanofibers is in the range of 2–4 μm. Antimicrobial agents are incorporated in PVP in an aqueous solution, then the prepared adduct is dried and mixed with PMMA in an organic solvent. In this nanofiber mat, PMMA provides the mechanical strength of the mat and assists in the gradual release of the antimicrobial agents. The formation of the PVP:PMMA nanofibers with incorporated antimicrobial agents at different stages was monitored by spectroscopy. The release of antimicrobial agents from the nanofibers mat during wetting was studied and confirmed by spectroscopy and mass spectrometry investigations.

Integron distribution and relationship to antimicrobial resistance in E. coli isolated from blood culture

PurposeThe aim of this study was to evaluate the distribution of integrons in strains of E. coli isolated from blood culture and the relationship between integrons and antimicrobial resistance. MethodsThe study included 100 E. coli strains sent to the Medical Microbiology Laboratory from different clinics between September 2022 and June 2023. Antibiotic susceptibility was evaluated according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The presence of integrons was determined by the inhouse polymerase chain reaction (PCR). ResultsIntegron positivity was detected in 45 (45%) of isolates, and class 1 integrons were found in 41 (41%), class 2 integrons in 2 (2%), and both class 1 integrons and class 2 integrons in 2 (2%). Class 3 integron positivity was not detected. In total, 63 cases of community origin and 37 cases of hospital origin were identified. When antibiotic resistance was evaluated, the highest sensitivity was noted for amikacin (1%), meropenem (5%), imipenem (6%), and the highest resistant antibiotics were ampicillin (82%), cepfuroxime sodium (65%), and amoxicillin/clavulanate (62%), respectively. Of the 16 antimicrobial substances evaluated, 10 had an antibiotic resistance rate of over 45%. In class 1 integron-positive samples, ampicillin resistance and trimethoprim/sulfamethoxazole resistance were higher than in negative samples (p = 0.02, p = 0.0001, respectively). Fifty-one (51%) samples were found to have multiple drug resistance (MDR). In total, 59.5% of hospital-acquired isolates and 46% of community-acquired isolates were considered to be MDR. The class 1 integron positivity in MDR samples was high (p = 0.038). ConclusionThe high MDR rates in both hospital-acquired and community-acquired isolates are alarming. In particular, class 1 integron monitoring is very important to prevent the spread of MDR isolates.

Analysis of antimicrobial biological activity of a marine Bacillus velezensis NDB.

A new strain of Bacillus velezensis NDB was isolated from Xiangshan Harbor and antibacterial test revealed antibacterial activity of this strain against 12 major pathogenic bacteria. The whole genome of the bacterium was sequenced and found to consist of a 4,214,838bp circular chromosome and a 7410bp circular plasmid. Furthermore, it was predicted by AntiSMASH and BAGEL4 to have 12 clusters of secondary metabolism genes for the synthesis of the inhibitors, fengycin, bacillomycin, macrolactin H, bacillaene, and difficidin, and there were also five clusters encoding potentially novel antimicrobial substances, as well as three bacteriocin biosynthesis gene clusters of amylocyclicin, ComX1, and LCI. qRT-PCR revealed significant up-regulation of antimicrobial secondary metabolite synthesis genes after 24h of antagonism with pathogenic bacteria. Furthermore, MALDI-TOF mass spectrometry revealed that it can secrete surfactin non-ribosomal peptide synthase and polyketide synthase to exert antibacterial effects. GC-MS was used to analyze methanol extract of B. velezensis NDB, a total of 68 compounds were identified and these metabolites include 16 amino acids, 17 acids, 3 amines, 11 sugars, 11 alcohols, 1 ester, and 9 other compounds which can inhibit pathogenic bacteria by initiating the antibiotic secretion pathway. A comparative genomic analysis of gene families showed that the specificity of B. velezensis NDB was mainly reflected in environmental adaptability. Overall, this research on B. velezensis NDB provides the basis for elucidating its biocontrol effect and promotes its future application as a probiotic.

Trends in the Incorporation of Antiseptics into Natural Polymer-Based Nanofibrous Mats.

Nanofibrous materials represent a very promising form of advanced carrier systems that can be used industrially, especially in regenerative medicine as highly functional bandages, or advanced wound dressings. By incorporation of antimicrobial additives directly into the structure of the nanofiber carrier, the functionality of the layer is upgraded, depending on the final requirement-bactericidal, bacteriostatic, antiseptic, or a generally antimicrobial effect. Such highly functional nanofibrous layers can be prepared mostly by electrospinning technology from both synthetic and natural polymers. The presence of a natural polymer in the composition is very advantageous. Especially in medical applications where, due to the presence of the material close to the human body, the healing process is more efficient and without the occurrence of an unwanted inflammatory response. However, converting natural polymers into nanofibrous form, with a homogeneously distributed and stable additive, is a great challenge. Thus, a combination of natural and synthetic materials is often used. This review clearly summarizes the issue of the incorporation and effectiveness of different types of antimicrobial substances, such as nanoparticles, antibiotics, common antiseptics, or substances of natural origin, into electrospun nanofibrous layers made of mostly natural polymer materials. A section describing the problematic aspects of antimicrobial polymers is also included.

Determining the effect of treatment with antimicrobial substances before storage on the preservation of lemons

The problem solved is to determine safer and more effective technologies for post-harvest processing of fruits. To achieve the goal, lemon fruits (of different degrees of wilting) were cut crosswise, each piece was treated with miramistin and deсasan in concentrations of 0.1 %, 0.3 %, and 0.5 %. The samples were placed on agar blocks with pure cultures of pathogens and placed in wet Petri dishes, kept at a temperature of 25 °C in a thermostat for 6–10 days; the experiment was repeated three times. The research aimed to establish the concentration of antimicrobial drugs for treating lemons; determine the weight loss of lemon fruits depending on the storage temperature. The object of the study is the process of preserving the quality of lemon fruits during post-harvest treatment with antiseptics during cold storage. It is proposed to treat lemon fruits with miramistin and deсasan in concentrations of 0.3 % and 0.5 % in order to inhibit the development of blue and green mold during storage. Damage to turgor fruits is two times less than that of weakly wilted ones. At a storage temperature of 10 °C, fruits are stored for 40–45 days. At the same time, daily losses are 0.49 %. Lowering the storage temperature to 4 °C extends the storage period to 90–100 days, with a daily mass loss of 0.08 %. A curvilinear correlation dependence of the second order of weight loss of lemon fruits on the duration of storage was established (R2=0.9758–0.9903). Treatment with antiseptics makes it possible to implement environmentally friendly solutions that will make it possible to exclude chemically synthesized fungicides and preserve the natural properties of fresh citrus fruits after harvesting, as well as extend their shelf life. In the development of new, low-cost, environmentally friendly, and affordable technologies, this is an important technique

STUDY ON THE ANTAGONISTIC ACTIVITY AGAINST TWO PATHOGENIC BACTERIA IN HUMANS OF STREPTOMYCES MIP_L26 ISOLATED FROM SOIL IN THE ROOT ZONE OF THE MAY CHANG TREE (LITSEA CUBEB)

Purpose: Study on the antagonistic activity against two pathogenic bacteria in humans (Staphylococcus aureus and Streptococcus pneumoniae) of the Streptomyces MIP_L26 (Called MIP_L26), isolated from the soil in the root zone of the May Chang tree; to investigate the biological characteristics of MIP_L26 Subjects and methods: Experimental study, determine the antimicrobial activity against two pathogenic bacteria in humans (Staphylococcus aureus and Streptococcus pneumoniae), and some biological characteristics of MIP_L26. Results: MIP_L26 was identified as having a strong antagonistic ability against the two bacteria causing Staphylococcus aureus and Streptococcus pneumoniae with an antibacterial ring diameter of 18 ± 5 mm and 13 ± 5 mm, respectively. Based on classification according to morphological, physiological, and biochemical characteristics, combined with the results of 16S rRNA gene sequencing, MIP_L26 was identified as Streptomyces gancidicus MIP_L26. The fermentation medium for the biosynthesis of antibacterial substances was ISP6 and the recovery time for antimicrobial substances was after 72 hours of fermentation.

Antibacterial and antioxidant properties and phytochemical screening of Laurus nobilis L. extract from Ethiopia

Microbial resistance to antibiotics and the shortage of efficient antimicrobial agent has necessitated the search for a better antimicrobial agent from various sources. Plants secondary metabolites are the major sources for discovery of new bioactive chemical compounds. The objective of this study was to determine the antibacterial and antioxidant activities of Laurus nobilis leaf extract and its essential oil against human pathogenic microorganisms and to analyse its chemical composition. The leaf of L. nobilis (500 g) was air-dried, powdered and extracted using four different solvents. The crude extract and the essential oil were tested against four Gram-negative and two Gram-positive bacterial strains. The radical scavenging activity of the crud extract was examined using DPPH assay. Bacterial inhibition activity of the crude extract increased with increased concentration from 25 mg/mL to 200 mg/mL. The maximum inhibition zone was recorded against Enterococcus faecalis 13.33±1.52 mm, Escherichia coli 14.33±1.53 mm and Salmonella typhimurium 16.00±1.00 mm, respectively. MeOH extract (1000 µg/mL) showed superior radical scavenging property (0.02) than ascorbic acid (0.05). The analysis of the oil using GC-MS indicated the presence of 48 chemical substances accounting for 91.4 % of the total compositions. The finding of this study showed that bay leaf has considerable antimicrobial and antioxidant activities. Further evaluation of this plant is recommended with particular focus on the mechanisms of action of the antimicrobial substance.

Nanocomposites and their application in antimicrobial packaging.

The advances in nanocomposites incorporating bioactive substances have the potential to transform the food packaging sector. Different nanofillers have been incorporated into polymeric matrixes to develop nanocomposite materials with improved mechanical, thermal, optical and barrier properties. Nanoclays, nanosilica, carbon nanotubes, nanocellulose, and chitosan/chitin nanoparticles have been successfully included into polymeric films, resulting in packaging materials with advanced characteristics. Nanostructured antimicrobial films have promising applications as active packaging in the food industry. Nanocomposite films containing antimicrobial substances such as essential oils, bacteriocins, antimicrobial enzymes, or metallic nanoparticles have been developed. These active nanocomposites are useful packaging materials to enhance food safety. Nanocomposites are promising materials for use in food packaging applications as practical and safe substitutes to the traditional packaging plastics.

Co-inoculation of the endophytes Bacillus thuringiensis CAPE95 and Paenibacillus polymyxa CAPE238 promotes Tropaeolum majus L. growth and enhances its root bacterial diversity.

Tropaeolum majus L. is a versatile edible plant that is widely explored due to its medicinal properties and as a key element in intercropping systems. Its growth could be improved by the use of biofertilizers that can enhance nutrient uptake by the plant or provide tolerance to different abiotic and biotic stresses. In a previous study, 101 endophytes isolated from T. majus roots showed more than three plant growth-promoting (PGP) features in vitro, such as phosphate mineralization/solubilization, production of siderophores, antimicrobial substances and indole-related compounds, and presence of the nifH gene. To provide sustainable alternatives for biofertilization, the genomes of two promising endophytes-CAPE95 and CAPE238-were sequenced to uncover metabolic pathways related to biofertilization. Greenhouse experiments were conducted with 216 seeds and 60 seedlings, half co-inoculated with the endophytes (treatment) and half inoculated with 1X PBS (control), and the impact of the co-inoculation on the plant's bacteriome was accessed through 16S rRNA gene metabarcoding. The strains CAPE95 and CAPE238 were taxonomically assigned as Bacillus thuringiensis and Paenibacillus polymyxa, respectively. Metabolic pathways related to the enhancement of nutrient availability (nitrogen fixation, sulfate-sulfur assimilation), biosynthesis of phytohormones (indole-3-acetic acid precursors) and antimicrobial substances (bacilysin, paenibacillin) were found in their genomes. The in vivo experiments showed that treated seeds exhibited faster germination, with a 20.3% higher germination index than the control on the eleventh day of the experiment. Additionally, treated seedlings showed significantly higher plant height and leaf diameters (p < 0.05). The bacterial community of the treated plants was significantly different from that of the control plants (p < 0.001) and showed a higher richness and diversity of species (Chao and Shannon indexes, p < 0.001). A higher relative abundance of potential synergistic PGP bacteria was also shown in the bacteriome of the treated plants, such as Lysinibacillus and Geobacter. For the first time, co-inoculation of B. thuringiensis and P. polymyxa was shown to have great potential for application as a biofertilizer to T. majus plants. The bacterial consortium used here could also be explored in other plant species in the future.

The Effects of Silver Nanoparticles on the Antimicrobial and Biodegradation of Cornstarch Bioplastic

The development of bioplastics is currently increasing, because bioplastics are an effort to reduce landfill waste. One of the bioplastics that has good degradation ability is cornstarch. The addition of nanoparticles was carried out to improve the properties of bioplastic packaging. One example of the application of nanotechnology in food packaging is silver nanoparticles (AgNP), known as antimicrobial substances. This research was conducted to determine the effect of adding AgNP (0%, 1%, and 2%) on the antimicrobial and biodegradation of cornstarch bioplastics. Bioplastics are made by casting method. AgNP was used from the synthesis of silver nitrate (AgNO3) and trisodium citrate dihydrate (C6H5Na3O7.2H2O) as a reducing agent and stabilizer by chemical reduction method, which was then analyzed by FTIR. The results obtained showed that cornstarch bioplastic AgNP 1% has the ability to estimate the fastest degradation time among other concentrations with an addition of 103 days. Cornstarch bioplastic AgNP 2% had the best ability to inhibit bacterial growth, with antibacterial inhibition zone diameters of 11.03 mm (Staphylococcus aureus) and 10.61 mm (Escherichia coli). However, AgNP could not inhibit the mold growth of Aspergillus niger. The addition of AgNP to cornstarch bioplastics can increase the degradation capabilities and antibacterial activity of bioplastics.

Control of Escherichia coli in Poultry Using the In Ovo Injection Technique.

Pathogens, such as Escherichia coli (E. coli), have been identified as significant causes of poultry mortality. Poultry can serve as potential sources of E. coli transmission, even when asymptomatic, posing a substantial threat to food safety and human health. The in ovo administration of antimicrobials is crucial for preventing and/or effectively combating acute and chronic infections caused by poultry pathogens. To achieve this goal, it is critical that antimicrobials are properly injected into embryonic fluids, such as the amnion, to reach target tissues and trigger robust antimicrobial responses. Several protocols based on antimicrobials were evaluated to meet these requirements. This review analyzed the impacts of antimicrobial substances injected in ovo on the control of E. coli in poultry. The reduction in infection rates, resulting from the implementation of in ovo antimicrobials, combined with efforts aimed at hygienic-sanitary action plans in poultry sheds, reinforces confidence that E. coli can be contained before causing large scale damage. For example, antimicrobial peptides and probiotics have shown potential to provide protection to poultry against infections caused by E. coli. Issues related to the toxicity and bacterial resistance of many synthetic chemical compounds represent challenges that need to be overcome before the commercial application of in ovo injection protocols focused on microbiological control.

Antagonistic Effects of Lactic Acid Bacteria Isolated from Ethiopian Traditional Fermented Foods and Beverages Against Foodborne Pathogens.

Lactic acid bacteria (LAB) found in Ethiopian traditional fermented foods and beverages have potential antagonistic effects against foodborne pathogens due to their capacity to produce various antimicrobial metabolites. This study evaluated the antagonistic activity of LAB isolated from Ethiopian traditional fermented foods and beverages against foodborne pathogens and characterized their antimicrobial substances. A total of 180 traditional fermented foods and beverages were collected, and the antagonistic activities of LAB were evaluated against selected foodborne pathogens. The effects of pH, temperature, enzymes, and food additives on the antagonistic effects of cell-free supernatant produced by LAB were investigated. LAB identification and characterization were conducted using an integrated phenotypic approach and MALDI TOF MS spectrum analysis, and data were analyzed using one-way ANOVA and Tukey post hoc analysis. A total of 956 LAB were isolated, of which seventeen (17 LAB) isolates of Pediococcus pentosaceus (Pc. pentosaceus (n = 7)), Pediococcus acidilactici (Pc. acidilactici (n = 2)), Enterococcus faecium (Ec. faecium (n = 6)), and Lactococcus lactis (Lc. lactis (n = 2)) were screened for antagonistic activity based on their ability to produce bacteriocins, probiotic activity, and preservative potential. Pc. pentosaceus JULABB16, Pc. pentosaceus JULABB01, and Ec. faecium JULABBr39 showed strong antagonistic activity against all pathogens, with mean inhibition zone diameters ranging from 23.50 to 35.50mm. Lc. lactis, Pc. pentosaceus, Pc. acidilactici, and Ec. faecium produced bioactive metabolites that were sensitive to proteolytic enzymes and capable of withstanding high temperatures (80-100°C) and acid concentrations (pH 2-10). The CFS produced by Lc. lactis, Pc. pentosaceus, Pc. acidilactici, and Ec. faecium showed the most impending antagonistic activity against all pathogens. The bioactive substances produced by LAB isolates had promising effects against food spoilage and pathogenic bacteria, making them potential natural food preservatives.

Smart Materials Design for Antibacterial Application.

In response to the escalating issue of antibiotic-resistant bacteria adhering to and thriving on medical equipment, scientists are pioneering innovative "intelligent" materials and coatings. These advancements entail the targeted release of antimicrobial substances, specifically activated when bacteria are detected. The next section discusses three revolutionary substances: hydrogels, nanoparticles, and thin films. Furthermore, intelligent antibacterial materials are divided into 2 groups based on the triggering source: those that react to biological stimuli and those that react to non-biological ones, like temperature and electric cues associated with bacterial presence, such as pH shifts or bacterial enzyme discharge. Moreover, because of their simple construction technique, outstanding biocompatibility, and robust antibacterial characteristics derived from polyphenols and metal ions, metallic-polyphenolic nanoparticles (MPNs) have obtained substantial interest in tackling antimicrobial infections. This article presents an introduction to several MPN-centered biomaterials (like nanoparticles, coatings, capsules, and hydrogels) and highlights the latest advancements in research in its applications for addressing microbial threats in the field of biomedicine. Furthermore, the usage of smart materials is classified based on their application domains, encompassing medical implants, waste reduction, and nano-engineered systems.