Antimicrobial Chemicals Research Articles

Effect of soil burial exposure on durability of alkali-activated binder-treated jute geotextile

The use of natural fibers for ground improvement has gained a lot of popularity in the present world in order to achieve sustainability. However, the major problem of using a natural fiber in soil is its biodegradability within a short period of 6–12 months. Research has proved that the life span of natural jute can be improved by treating them with antimicrobial chemicals. But these chemical treatments are expensive as well as lead to leaching. The present paper proposes a sustainable and environment friendly method to improve the strength and durability properties of jute geotextiles by treating it with alkali-activated binder (AAB). Reaction between an activator solution of sodium hydroxide and sodium silicate and an aluminosilicate precursor (Class F Fly ash) lead to the formation AAB. The water to solid ratio is varied in the present study from 0.35 to 0.45 to obtain the optimum workable solution. A series of microstructural (Stereomicroscopy, Fourier-transform infrared spectroscopy and scanning electron microscope) and mechanical characterization (thickness, mass density and aperture opening size) tests along with durability tests (soil burial) are conducted for both untreated and treated jute. Locally available red soil is used for the soil burial study. It is inferred from microstructural studies that the lignocellulosic structure present in jute fiber is not fully altered by AAB treatment. From durability test, it is observed that the tensile strength of AAB-treated jute improves almost twofold in comparison to untreated jute. The durability tests indicate that after a burial period of 6 months, the tensile strength AAB-treated jute is significantly greater than untreated jute.

Effect of Antimicrobial Peptides and Chemicals Produced by Animals on Liver Microsomal Enzymes CYP450

The problem of multidrug-resistant pathogens as bacteria, fungi and yeast in addition to the restriction of using antibiotics as growth promoting substances in feed has attracted attention for looking for alternative sources instead of conventional antibiotics like natural products which have antimicrobial activity. Much interest and researches have been focused on using natural antimicrobial peptides and chemicals extracted from animal secretions and some insect’s venoms as they exhibit antimicrobial activity against pathogens with lower resistance and higher synergistic effects if they were given in combination with blends of them. In this paper, some antibacterial peptides extracted from honeybees venom and expression with yeast Saccharomyces cerevisiae will be discussed as well as antimicrobial chemicals extracted from giraffes in addition to their inhibitory effects on liver microsomal enzymes CYP450 will be discussed also with its activity against microorganisms which are Agrobacterium rhizogenes, Aspergillus niger, Candida albicans and E. coli using optical density analysis technique then their minimum inhibitory concentrations (MIC) will be determined as well as ICs 50 to measure the potency to inhibit a biological function using programmes like Gene5, graph pad prism and clone manager as well as testing antimicrobial activity of some chemicals which are provided in animal secretions.

Quaternary ammonium compounds: perspectives on benefits, hazards, and risk

Quaternary ammonium compounds are antimicrobial chemicals that provide significant public health benefits by controlling bacteria and viruses that cause infections such as colds, flu, and COVID. The benefits of antimicrobial QACs are seen in increased quality-of-life measures, such as reduced time away from work and school and reduced medical costs. As active antimicrobial agents, QACs and QAC-containing consumer and professional products are highly regulated by authorities such as the US Environmental Protection Agency and the European Chemicals Agency. A complete database of guideline safety studies, covering human and environmental health, is available and has been reviewed by multiple regulatory agencies globally. The conclusions of regulatory agencies from these studies indicate no concerns regarding reproductive effects, genotoxicity, carcinogenicity, or other systemic adverse effects. In contrast, some published academic studies provide mixed findings on lipid synthesis, reproductive effects, and asthma. However, many of these studies have been found not to be robust in design and lacked appropriate controls to support conclusions of a clear and direct association with an adverse effect. The hazard data for the QACs show that their primary critical effects are point-of-contact effects such as irritation, which exhibit a threshold and occur in a dose–response manner. This review compares toxicity information for QACs, examines human exposures, and quantifies the risks estimated from QAC product use. QACs are an important cleaning and hygiene tool, and the abundance of safety data generated for them provides assurance they can be safely used in professional and household products.

Effect of Antimicrobial Peptides and Chemicals Produced by Animals on <i>Aspergillus fumigatus</i>

The problem of multidrug-resistant pathogens as bacteria, fungi and yeast in addition to the restriction of using antibiotics as growth promoting substances in food has attracted the attention to looking for alternative sources instead of conventional antibiotics like natural products which have antimicrobial activity. Much interests and researches have been focused on using natural antimicrobial peptides and chemicals extracted from animal secretions and some insect’s venoms as they exhibit antimicrobial activity against pathogens with lower resistance and higher synergistic effects if they were given in combination with blends of them. In this paper, some antimicrobial chemicals extracted from giraffes are shown in addition to their activity against Aspergillus fumigatus species using optical density analysis technique then their Minimum Inhibitory Concentrations (MIC) will be determined as well as ICs 50 to measure the potency to inhibit a biological function using programmes like Gene5, graph pad prism as well as testing antimicrobial activity of some chemicals which are provided in animal secretions.

Inhibitory mechanism of Chinese herbal medicine extracts on Escherichia coli and its application to fermented-bag sausage

Since Chinese Herbal Medicine contain many antimicrobial chemicals, they have great potential as new antimicrobial agents. Five Chinese Herbal Medicine extracts were obtained from hawthorn leaf, ginkgo leaf, bamboo leaf, redskin peanut, and lotus leaf by thermal reflux. The optimal mixed ratio was 2: 2: 5: 9 (hawthorn leaf, ginkgo leaf, bamboo leaf, redskin peanut) using the orthogonal method. The minimum inhibitory concentration (MIC) was 1.3 mg/mL. The total flavonoid content in the mixed-plant extract was 21.5%, and the quercetin, vitexin, different vitexin, galangal and resveratrol content were 0.32, 4.38, 1.87, 0.36 and 1.35 mg/L, respectively. The inhibitory mechanism was studied by changes in growth curves, cellular structure, cell-wall permeability and cell-membrane integrity. Results showed that the addition of plant extracts reduced the presence of E. coli, while increasing AKP, conductivity and ion-channel enzymes. Plant extracts damaged E. coli cell-walls and cell-membrane structures. The addition of 6% mixed-plant extract showed a positive effect on the quality and safety of fermented-bag sausage.

Antimicrobial Air Filter Coating with Plant Extracts Against Airborne Microbes

Antimicrobial air filters are required to protect humans from the risk of secondary bioaerosol pollution as well as airborne particles. Three plant extracts (tea-tree oil, rosemary, and garlic) were selected to replace antimicrobial chemicals in air filters. The antimicrobial activity of plant extracts was investigated using Micrococcus luteus and Escherichia coli. Phytochemicals present in the three plant extracts were identified using a gas chromatograph coupled with a mass spectrometer. The extracts were spray-coated on polyethylene terephthalate filter surfaces using silicate polymeric coating and evaluated via X-ray photoelectron spectroscopy and a scanning electron microscope with energy dispersive spectroscopy. After coating, an increase of 9.1% in the pressure drop was observed. The strain Micrococcus luteus was used to evaluate the antimicrobial activity of the air filter. After bioaerosol exposure, the tea-tree oil-coated filters immediately induced M. luteus cell inactivation (40–55%), whereas the rosemary and garlic coated filters did not. However, 48 h after exposure, a significant M. luteus inactivation of 99.99%, 99.0%, and 99.9% was recorded for concentrations of 2.89, 6.73, and 11.51 mg/cm2 for the tea-tree, rosemary, and garlic extracts, respectively. The coated filters exhibited high antimicrobial activity, thereby indicating significant potential for application as self-cleaning air filters.

New insights into the cellular mechanism of triclosan-induced dermal toxicity from a combined metabolomic and lipidomic approach

Triclosan (TCS), an antimicrobial chemical, has been widely used in consumer goods and personal care products. Despite skin is the crucial entry of TCS into human body, previous studies mainly focused on the potential health risks after TCS absorption. Considering in vivo evidences have indicated that topical use of TCS could lead to serious skin lesions, it is thus in urgent need to unveil the underlying mechanisms of dermal toxicity caused by TCS application. In this study, mass spectrometry-based metabolomics and lipidomics were applied to investigate TCS-induced changes of endogenous small molecular metabolites and lipids in human HaCaT keratinocytes. Metabolic biomarker analysis revealed that TCS exposure was associated with the elevation of purine and glutathione metabolism, down-regulation of amino acid metabolism and dysregulation of lipid metabolism in keratinocytes. These intracellular metabolic disorders consequently led to the overproduction of reactive oxygen species (ROS) and accumulation of ammonia. TCS-induced oxidative stress was further validated in human HaCaT cells, functioning as the crucial factor for the generation of pro-inflammatory cytokines that triggered inflammation and lipid disturbances related to cell apoptosis. Our findings update the existing understanding of skin health risks of TCS application at the molecular level.

The effects of a myrmecochore-produced chemical on entomopathogenic fungal growth and seed-dispersing ant survival rates and foraging patterns.

Myrmecochory, a type of ant-mediated seed dispersal, is a diffuse, widespread mutualism in which both partners are purported to benefit from the services or rewards of the other. However, ant benefits in this interaction are conflicted and understudied, especially in the context of microbial third parties. Here, we investigate the effect of a myrmecochore plant-produced antimicrobial chemical (sanguinarine) on the growth of a common entomopathogenic fungus (Beauveria bassiana). We then explore whether sanguinarine, through its effect on entomopathogen growth, might influence ant survival and foraging behavior. At high concentrations, sanguinarine increased the growth of B. bassiana, but fungal growth was not affected at concentrations of sanguinarine near natural levels produced in seeds. When ant colonies were exposed to B. bassiana, survival was not affected by a sanguinarine-supplemented diet. Furthermore, ant foraging patterns (preference for or avoidance of food items with sanguinarine) did not change when ants were exposed to the entomopathogen. Though sanguinarine promotes the growth of an entomopathogen at higher concentrations, which might pose an additional risk for ants in myrmecochory, we assert that social immune behavioral defenses (such as grooming or redispersal of seeds after elaiosome consumption) help ants mitigate this risk. By incorporating a microbial third party into this ant-plant interaction, we seek to more fully understand the risks and benefits provided to both partners in this mutualism. We encourage the investigation of third-party influences in reciprocal pairwise interactions to assist in the understanding of the evolution and persistence of mutualisms.

The Application of Polysaccharides and Their Derivatives in Pigment, Barrier, and Functional Paper Coatings.

As one of the most abundant natural polymers in nature, polysaccharides have the potential to replace petroleum-based polymers that are difficult to degrade in paper coatings. Polysaccharide molecules have a large number of hydroxyl groups that can bind strongly with paper fibers through hydrogen bonds. Chemical modification can also effectively improve the mechanical, barrier, and hydrophobic properties of polysaccharide-based coating layers and thus can further improve the related properties of coated paper. Polysaccharides can also give paper additional functional properties by dispersing and adhering functional fillers, e.g., conductive particles, catalytic particles or antimicrobial chemicals, onto paper surface. Based on these, this paper reviews the application of natural polysaccharides, such as cellulose, hemicellulose, starch, chitosan, and sodium alginate, and their derivatives in paper coatings. This paper analyzes the improvements and influences of chemical structures and properties of polysaccharides on the mechanical, barrier, and hydrophobic properties of coated paper. This paper also summarizes the researches where polysaccharides are used as the adhesives to adhere inorganic or functional fillers onto paper surface to endow paper with great surface properties or special functions such as conductivity, catalytic, antibiotic, and fluorescence.

The role of RND-type efflux pumps in multidrug-resistant mutants of Klebsiella pneumoniae

The emergence of multidrug-resistant Klebsiella pneumoniae is a worldwide problem. K. pneumoniae possesses numerous resistant genes in its genome. We isolated mutants resistant to various antimicrobials in vitro and investigated the importance of intrinsic genes in acquired resistance. The isolation frequency of the mutants was 10−7–10−9. Of the multidrug-resistant mutants, hyper-multidrug-resistant mutants (EB256-1, EB256-2, Nov1-8, Nov2-2, and OX128) were identified, and accelerated efflux activity of ethidium from the inside to the outside of the cells was observed in these mutants. Therefore, we hypothesized that the multidrug efflux pump, especially RND-type efflux pump, would be related to changes of the phenotype. We cloned all RND-type multidrug efflux pumps from the K. pneumoniae genome and characterized them. KexEF and KexC were powerful multidrug efflux pumps, in addition to AcrAB, KexD, OqxAB, and EefABC, which were reported previously. It was revealed that the expression of eefA was increased in EB256-1 and EB256-2: the expression of oqxA was increased in OX128; the expression of kexF was increased in Nov2-2. It was found that a region of 1,485 bp upstream of kexF, was deleted in the genome of Nov2-2. K. pneumoniae possesses more potent RND-multidrug efflux systems than E. coli. However, we revealed that most of them did not contribute to the drug resistance of our strain at basic levels of expression. On the other hand, it was also noted that the overexpression of these pumps could lead to multidrug resistance based on exposure to antimicrobial chemicals. We conclude that these pumps may have a role to maintain the intrinsic resistance of K. pneumoniae when they are overexpressed. The antimicrobial chemicals selected many resistant mutants at the same minimum inhibitory concentration (MIC) or a concentration slightly higher than the MIC. These results support the importance of using antibiotics at appropriate concentrations at clinical sites.

A College–High School Collaboration to Support Authentic Microbiology Research

A partnership between a community college biology professor and a local high school teacher was established to engage high school students in authentic microbiology research. High school students isolated actinomycetes from soil samples and tested them for their ability to produce antimicrobial chemicals. They also designed and carried out their own experiments with these isolates. Laboratory reports, written assignments, and quizzes were used to assess the scientific learning of the subject covered by the research project. The students' attitudes about science and scientific research were assessed using a standardized survey and written reflection questions. In completing this project, the students applied their knowledge of the scientific method and experimental design to address authentic research questions. They also learned several hands-on laboratory skills, including serial dilution, aseptic technique, isolation of pure cultures, Gram staining, microscopy, and antimicrobial testing. Student feedback was overwhelmingly positive – many expressed an increased interest in pursuing a career in science, and most felt that the project helped them gain confidence in their ability to do science. This project illustrates the importance of establishing partnerships between secondary schools and academic institutions to successfully introduce research to younger students.

Topical application of the antimicrobial agent triclosan initiates caspase 1 activation via effects on mitochondrial function

The skin plays a major role in the development of allergic disease. Triclosan is an antimicrobial chemical that is absorbed through the skin and has been associated with allergic disease. Mitochondria play important roles in immune cell function and recent studies demonstrate a role for mitochondria in the activation of the NLRP3 inflammasome. Triclosan affects mitochondrial function; however, its effects on the NLRP3 inflammasome have not yet been studied. We hypothesize that dermal triclosan exposure may activate caspase-1 through a mitochondrial based pathway. BALB/c mice were dermally exposed to 0-3% triclosan for 1-4 days. Twenty-four hours following final exposure, macrophage and neutrophil phenotyping along with mitochondrial mass and membrane potential were assessed by flow cytometry; extracellular ATP and caspase-1 activation were measured via luminescence-based assays. Mitochondrial morphology was assessed via transmission electron microscopy. Gene expression was evaluated via qPCR and protein via ELISA and western blot. Animals exposed to triclosan showed an increase in S100A8 and pro-IL-1β gene expression along with extracellular ATP in the skin. Macrophage and neutrophil cell number and frequency both increased in the dLN. Caspase-1 activation and IL-1β protein expression increased in the dLN, possibly due to cell migration. Mitochondrial membrane potential, mass, and ROS all decreased in the dLN along with a change in mitochondrial morphology; all possibly contributing to caspase-1 activation. These findings demonstrate a connection between mitochondria and immune function following dermal triclosan exposure and support the need for additional research to investigate this association and the immunological impact.

Chemical characterization, antioxidant, cytotoxicity, Anti-Toxoplasma gondii and antimicrobial potentials of the Citrus sinensis seed oil for sustainable cosmeceutical production

There are growing concerns about the chronic and acute effects of synthetic additives such as antibacterial, fragrances, colourants and stabilizing agents used in the production of various household products. Many household products and materials including cosmetic products are reportedly suspected to be carcinogenic with some acting as endocrine disruptors among other effects. Thus, environmental-friendly alternatives such as products that are rich in bioactive phytochemicals are becoming consumers' preferred choice especially in the beauty and cosmetic sector. ‘Green’ preparation of medicinal soaps devoid of any synthetic additives was made from underutilized tropical seed of Citrus sinensis seed oil and some natural additives comprising of natural honey, Ocimum gratissimum leaves extract, Moringa oleifera seed oil and coconut oil. Precisely, the seed oil of the underexplored C. sinensis was obtained via soxhlet extraction and saponified with natural lye solution at different ratios to produce soaps of varying characteristics. The incorporation of honey and Ocimum gratissimum leaf extract provided additional antimicrobial, antioxidant and fragrance properties. Physico-chemical parameters of the oil and soaps were determined following standard procedures while the fatty acid profile of the trans-esterified oil was determined using GC–MS. The antimicrobial potential of the oil and soaps were assessed using agar diffusion method at concentrations 200 mg/mL and below. Linoleic acid (36%) and oleic acid (27%) were the most prominent in C. sinensis seed oil. The soap had antimicrobial potential comparable to commercial product. The soap samples recorded highest anti-bacteria activities (22.0 ± 1.0–23.0 ± 1.0) against Staphylococcus aureus and Bacillus subtilis and notable anti-fungi activities (18.0 ± 1.0) against Penicillium notatum and Candida albicans. Additionally, the oil showed moderate anti-parasite (anit-toxoplasma gondii) activity (EC50 ≤ 500 μg/mL) but with improved selectivity that precludes oxidative stress while the prepared medicinal soaps exhibited remarkable antioxidant property. The utilization of these locally sourced resources will prevent the daily introduction of synthetic antimicrobial and antioxidant chemicals into the environment. The initiative avail a sustainable production of environmentally-benign cosmetic products besides conversion of waste to wealth agrees which aligns with the Sustainable Development Goals (SDGs).

Triclosan at environmental concentrations can enhance the spread of extracellular antibiotic resistance genes through transformation

The dissemination of antibiotic resistance mediated by horizontal transfer of antibiotic resistance genes (ARGs) is exacerbating the global antibiotic crisis. Currently, little is known about whether non-antibiotic, anti-microbial (NAAM) chemicals are associated with the dissemination of ARGs in the environment. In this study, we aimed to evaluate whether a ubiquitous NAAM chemical, triclosan (TCS), is able to promote the transformation of plasmid-borne antibiotic resistance genes (ARGs). By using the plasmid pUC19 carrying ampicillin resistance genes as the extracellular ARG and a model microorganism Escherichia coli DH5ɑ as the recipient, we found that TCS at environmentally detected concentrations (0.2 μg/L to 20 μg/L) significantly enhanced the transformation of plasmid-borne ARGs into E. coli DH5ɑ for up to 1.4-fold. The combination of phenotypic experiments, genome-wide RNA sequencing and proteomic analyses revealed that TCS exposure stimulated the reactive oxygen species (ROS) production for 1.3- to 1.5-fold, induced bacterial membrane damage and up-regulated the translation of outer membrane porin. Moreover, general secretion system Sec (1.4-fold), twin arginine translocation system Tat (1.2-fold) and type IV pilus secretion systems (2.5-fold) were enhanced by TCS, which might contribute to the DNA searching/capture by pilus. Together, TCS might increase the transformation frequency of ARGs into E. coli DH5ɑ by ROS over-production, damaging cell membrane barrier, mediating the pilus capture of plasmid and the translocation of plasmid via cell membrane channels. This study reports that TCS could accelerate the transformation of extracellular ARGs to competent bacteria at environmentally relevant concentrations. The findings advance our understanding of the fate of ARGs in ecosystems and call for risk assessments of NAAM chemicals on disseminating antibiotic resistance.

Potential classification of chemical immunologic response based on gene expression profiles

Occupational immune diseases are a serious public health burden and are often a result of exposure to low molecular weight (LMW) chemicals. The complete immunological mechanisms driving these responses are not fully understood which has made the classification of chemical allergens difficult. Antimicrobials are a large group of immunologically-diverse LMW agents. In these studies, mice were dermally exposed to representative antimicrobial chemicals (sensitizers: didecyldimethylammonium chloride (DDAC), ortho-phthalaldehyde (OPA), irritants: benzal-konium chloride (BAC), and adjuvant: triclosan (TCS)) and the mRNA expression of cytokines and cellular mediators was evaluated using real-time qPCR in various tissues over a 7-days period. All antimicrobials caused increases in the mRNA expression of the danger signals Tslp (skin), and S100a8 (skin, blood, lung). Expression of the TH2 cytokine Il4 peaked at different timepoints for the chemicals based on exposure duration. Unique expression profiles were identified for OPA (Il10 in lymph node, Il4 and Il13 in lung) and TCS (Tlr4 in skin). Additionally, all chemicals except OPA induced decreased expression of the cellular adhesion molecule Ecad. Overall, the results from these studies suggest that unique gene expression profiles are implicated following dermal exposure to various antimicrobial agents, warranting the need for additional studies. In order to advance the development of preventative and therapeutic strategies to combat immunological disease, underlying mechanisms of antimicrobial-induced immunomodulation must be fully understood. This understanding will aid in the development of more effective methods to screen for chemical toxicity, and may potentially lead to more effective treatment strategies for those suffering from immune diseases.

Evaluation of the effect of Carvacrol and Linalool on the growth of Staphylococcus aureus and E. coli enterotoxin and production of ent A and ent B toxins in Staphylococcus aureus and ST1 and ST2 toxins in E. coli enterotoxins

Diseases caused by the consumption of food contaminated with pathogenic bacteria are of a major threat to general health. Using natural substances as antimicrobial compounds seem effective for controlling the presence of pathogenic bacteria and increasing the shelf-life of processed foods. Among these compounds, extracts obtained from medicinal plants have antimicrobial properties and act as a source of antimicrobial substances against pathogens. Given their antimicrobial effects, herbal essences are usable as a substitute for antimicrobial chemicals in food industries. So the aim of this study was the evaluation of the effect of Carvacrol and Linalool on the growth of Staphylococcus aureus and E. coli enterotoxin and production of ent A and ent B toxins in Staphylococcus aureus and ST1 and ST2 toxins in E. coli enterotoxins. Carvacrol and linalool were prepared in dilutions of (1,500, 1/1000, 1/1500, 1/2000, 1/2500, 1/3000 ml / μg) and (1/100, 1/200, 1/400, 1/600, 1/800, 1/1000 ml/μg), respectively. The minimum inhibitory concentration was determined by the use of sterile 24 well plates and broth dilution. The minimum bactericidal concentration was obtained in a turbidity-absent culture, separately on the blood lipid agar medium in the case of Staphylococcus aureus, and Mckanaki agar in the case of Escherichia coli. Ent A and ent B toxins in Staphylococcus aureus were produced by high-performance liquid chromatography (HPLC) and STX 1 and STX 2 toxins in Escherichia coli were generated by Elisa method. The minimum inhibitory concentration of carvacrol was obtained at 1/1000 dilution on Escherichia coli, and 1/1500 dilution on Staphylococcus aureus, The minimum inhibitory concentration of linalool was obtained at 1/400 dilution on Escherichia coli and Staphylococcus aureus, the minimum bactericidal concentration of carvacrol was obtained at 1/1000 dilution on Escherichia coli and 1/2500 dilution on Staphylococcus aureus and the minimum bactericidal concentration of linalool was obtained at 1/400 dilution on Escherichia coli and Staphylococcus aureus. The effects of carvacrol and linalool on Ent A and Ent B toxins of Staphylococcus aureus and STX1 and STX2 toxins of E. coli showed the decreasing trend of toxin production at nanogram level. The results of this study showed that carvacrol and linalool had an inhibitory effect on the growth of both 2 bacteria and reduced the production of Ent A and Ent B toxins in Staphylococcus aureus and ST1 and ST2 toxins in Escherichia coli enterotoxigenic.

Characterization of Fecal Shiga Toxin-Producing Escherichia coli from Post-Weaning Cattle

ObjectivesShiga toxin-producing E. coli (STEC), which are often found in the intestinal tract of cattle and in their fecal matter, are among the most common foodborne pathogens of concern in beef production. Contamination from the fecal matter, both directly and indirectly, during harvest may compromise the safety of the beef products, which can have devastating impact on consumers and producers alike. While the microbial load present in cattle fecal matter may change as the cow matures, previous research has generally focused on analysis of the pathogen load late in the life cycle of cattle. There is merit in the analysis of this load earlier in the life cycle of cattle, as this may serve to subsequently control the pathogen load during later stages of production. As such, this study aims to assess the prevalence and characteristics of STEC in beef cattle production at the early post-weaning stage.Materials and MethodsRectal fecal samples from post-weaning cattle (n = 68) were collected. Ten grams of each sample was mixed and manually homogenized with 90mL tryptic soy broth (TSB) with added phosphates. The homogenized samples were spread-plated on CHROMagar STEC plates and incubated at 35°C for 24h before enumeration. To determine STEC prevalence, the homogenized samples were incubated at 42°C for 6 h, and streaked onto a second set of CHROMagar STEC plates, which were incubated at 35°C for 24h. Colonies with a purple coloration were STEC-positive. Two random STEC-presumptive colonies from each sample were tested via subsequent PCR amplification and gel electrophoresis to confirm the presence of stx1, stx2, and/or eae genes.Acid-resistant strains of presumptive STEC colonies from the enriched samples were collected and inoculated into TSB for recovery. One hundred microliters of the inoculated sample were then transferred into TSB without dextrose and incubated at 35°C for 24h, and finally challenged in acidified TSB without dextrose (pH = 3.50) for 1h and 6h. One hundred microliters of each survival sample were plated onto tryptic soy agar (TSA), and incubated at 35°C for 48h.ResultsThe fecal samples had an average 4.79 ± 1.24 log CFU/g (ranging 2.30 to 6.83) of STEC colonies. All samples were STEC-positive, as all samples had at least one of the three genes tested for (stx1, stx2, eae). All sixty-eight samples were confirmed positive for gene stx1, 12% (8 of 68) samples were confirmed positive for stx2, 62% (42 of 68) of samples were confirmed positive for eae, and 12% (8 of 68) were positive for all three genes. Of 67 samples tested for acid resistance, 34% (23 of 67) survived after 6 h in acidified growth media (pH = 3.50).ConclusionThis study provided preliminary data on the pathogen load of early post-weaning cattle. The prevalence of acid resistance shown may be a possible cause of concern, as these surviving bacteria can survive high acidic conditions. This may expedite the spread of acid-resistant pathogens within the food supply chain as acidic antimicrobial chemicals become ineffective in reducing pathogen populations. These results may be used as a baseline for future research regarding STEC prevalence or acid resistance aimed at reducing pathogen load in beef cattle production. Given the prevalence of acid resistance, further development is recommended for non-acid post-harvest antimicrobial interventions to reduce the presence of acid resistant STEC.

Relationships between parental use of antimicrobial household products and development of allergic rhinitis in children

TPS 751: Farms, antibiotics, infections, Exhibition Hall, Ground floor, August 26, 2019, 3:00 PM - 4:30 PM Antimicrobial chemicals are contained in various household and personal care products. This study examined relationships between the use of antimicrobial household products and allergic rhinitis in children in South Korea. In total, 1,538 elementary school students in Seoul were tracked from 2012 to 2017 (first to sixth grade). Among these, 917 children (mean age 7 years) who did not have allergic rhinitis were included in the final analysis. Data on demographic characteristics and frequency of antimicrobial household product use were collected using questionnaires completed by the parents of the children. Antimicrobial exposure (AE) scores were calculated for each child by summing their exposure to three antimicrobial household products. During the follow up, we estimated the cumulative incidence of doctor-diagnosed allergic rhinitis based on International Study of Asthma and Allergies in Childhood questionnaires. During follow up, the cumulative incidence of allergic rhinitis was 25.6%. A multivariable logistic analysis adjusted for demographic factors revealed that the children with AE scores ≥ median value were more likely to have allergic rhinitis than those with AE scores < median value (adjusted odds ratios, aOR = 1.37, 95% CI = 1.01–1.87). About 1 of 4 children developed allergic rhinitis during the 5-year follow–up and AE score groups were significantly associated with the incidence of allergic rhinitis. Parental use of AHPs may be associated with development of allergic rhinitis.

Fatty Acids and Herbal Medicine

Background:Fatty acid is a type of carboxylic acid with carbon chain that can be short (4 carbons, such as butyric acid) or long (14 carbons and more, like DHA). Generally, fatty acids are divided into two groups of unsaturated fatty acids and saturated fatty acids. They have important and valuable medicinal properties especially against microbial pathogens.Objective:Studies have shown that the epidemic of the twentieth century's heart disease is due to the abuse of trans fatty acids. The consumption of various fatty acids has various therapeutic effects on various diseases.Method:Relevant articles were searched from Google Scholar, Pub Med, Scopus, Science direct, and Cochrane library.Results:Getting omega-3 fatty acids through diet and supplements affects both acute and chronic inflammation. Consumption of omega-3 fatty acids can slow down the growth of cancer, increase the effect of chemotherapy and reduce the side effects of chemotherapy or cancer. This can be done by reducing angiogenesis in the tumor, creating the differentiation of cancer cells, reducing the risk of heart attack from cancer, etc.Conclusion:In general, fatty acids are valuable and affordable, and available with numerous medicinal properties, including anti-fungal and anti-bacterial properties that can be extracted from and used by many sources, especially many medicinal plants. Since antimicrobial chemicals generally have many side effects and have resistance to many microbial species, various studies and experiments to identify and extract fatty acids and their application to the title of the pharmaceutical formulation are essential.

The AP-1-like transcription factor ChAP1 balances tolerance and cell death in the response of the maize pathogen Cochliobolus heterostrophus to a plant phenolic.

Fungal pathogens need to contend with stresses including oxidants and antimicrobial chemicals resulting from host defenses. ChAP1 of Cochliobolus heterostrophus, agent of Southern corn leaf blight, encodes an ortholog of yeast YAP1. ChAP1 is retained in the nucleus in response to plant-derived phenolic acids, in addition to its well-studied activation by oxidants. Here, we used transcriptome profiling to ask which genes are regulated in response to ChAP1 activation by ferulic acid (FA), a phenolic abundant in the maize host. Nuclearization of ChAP1 in response to phenolics is not followed by strong expression of genes needed for oxidative stress tolerance. We, therefore, compared the transcriptomes of the wild-type pathogen and a ChAP1 deletion mutant, to study the function of ChAP1 in response to FA. We hypothesized that if ChAP1 is retained in the nucleus under plant-related stress conditions yet in the absence of obvious oxidant stress, it should have additional regulatory functions. The transcriptional signature in response to FA in the wild type compared to the mutant sheds light on the signaling mechanisms and response pathways by which ChAP1 can mediate tolerance to ferulic acid, distinct from its previously known role in the antioxidant response. The ChAP1-dependent FA regulon consists mainly of two large clusters. The enrichment of transport and metabolism-related genes in cluster 1 indicates that C. heterostrophus degrades FA and removes it from the cell. When this fails at increasing stress levels, FA provides a signal for cell death, indicated by the enrichment of cell death-related genes in cluster 2. By quantitation of survival and by TUNEL assays, we show that ChAP1 promotes survival and mitigates cell death. Growth rate data show a time window in which the mutant colony expands faster than the wild type. The results delineate a transcriptional regulatory pattern in which ChAP1 helps balance a survival response for tolerance to FA, against a pathway promoting cell death in the pathogen. A general model for the transition from a phase where the return to homeostasis dominates to a phase leading to the onset of cell death provides a context for understanding these findings.