Targeting Salmonella Typhimurium Invasion and Intracellular Survival Using Pyrogallol

Antibacterial activity of a plant natural poly-phenol against zoonotic Streptococcus suis

The increasing emergence and dissemination of multi-drugs resistant bacterial pathogens accelerate the desires for novel antimicrobials. Natural products are great resources for the discovery of antimicrobial compound. In this study, pyrogallol was screened from 25 poly-phenols for its antibacterial activity against multi-drugs resistant Streptococcus suis (S. suis), particularly, pyrogallol had synergistic antimicrobial effect with doxycycline, sulfafurazole and clindamycin, respectively. Pyrogallol showed significant inhibitory effects on bacterial biofilm formation, and caused cell wall and cell membrane injury to S. suis. Furthermore, mechanistic studies demonstrated that pyrogallol might interact with peptidoglycan and decreased the expression of virulence and growth-related genes, such as ftsZ, stK, sly, fbps and luxS. In cell model, pyrogallol protected Nptr cells from S. suis-mediated cell damage. Finally, in mouse model, the pyrogallol and antibiotics combination groups with dosage given in the half could be as effective as antibiotics groups. In summary, these results demonstrated the capacity of pyrogallol serving as a candidate for novel antibiotic alternative and antibiotic adjuvant to circumvent the antibiotics resistance and reduced antibiotic consumption.

Impact of nafcillin and diosmin on the attachment, invasion, and stress survival of Salmonella Typhimurium

Salmonella Typhimurium is an invasive intracellular pathogen that employs various factors for its survival within host cells. To mitigate S. Typhimurium survival, it is crucial to identify factors that influence bacterial survival and to develop drugs that inhibit these factors. In this study, we investigated the effects of nafcillin and diosmin, both of which have been identified as inhibitors of Lon protease, on the intracellular survival of S. Typhimurium and its survival under various stress conditions. Additionally, we examined the expression of genes associated with the type II toxin-antitoxin system to enhance our understanding of the impact of these systems on the bacterium's survival. Our findings indicate that while nafcillin and diosmin did not affect S. Typhimurium attachment, they significantly reduced bacterial intracellular survival, particularly in Hep2 cells after 16 h. These inhibitors were also effective in decreasing bacterial survival under oxidative and acidic stress conditions. Furthermore, gene expression analysis revealed that although there were variations in the expression of TA system genes in S. Typhimurium across different cell lines, the relEB system emerged as the most effective among those studied, exhibiting the highest increase in expression. This study highlights the efficacy of nafcillin and diosmin in reducing the intracellular survival of S. Typhimurium as well as its survival under stress conditions. These findings suggest potential new strategies for developing therapies aimed at preventing S. Typhimurium infections.

Quercetin and Silybin Decrease Intracellular Replication of Piscirickettsia salmonis in SHK-1 Cell

Piscirickettsia salmonis is the pathogen that has most affected the Chilean salmon industry for over 30 years. Considering the problems of excessive use of antibiotics, it is necessary to find new strategies to control this pathogen. Antivirulence therapy is an alternative to reduce the virulence of pathogens without affecting their growth. Polyphenolic compounds have been studied for their antiviral capacity. In this study, the capacity of quercetin and silybin to reduce the intracellular replication of P. salmonis in SHK-1 cells was evaluated. For this, three different infection protocols in Salmon Head Kidney-1(SHK-1) cells were used: co-incubation for 24 h, pre-incubation for 24 h prior to infection, and post-incubation for 24 h after infection. In addition, the effect of co-incubation in rainbow trout intestinal epithelial cells (RTgutGC) and the effect on the phagocytic capacity of SHK-1 cells were evaluated. The results obtained showed that quercetin and silybin decreased the intracellular replication of P. salmonis in SHK-1 cells when they were co-incubated for 24 h; however, they did not have the same effect in RTgutGC cells. On the other hand, both compounds decreased the phagocytosis of SHK-1 cells during co-incubation. These results are promising for the study of new treatments against P. salmonis.

Pharmacodynamic Profiling of Amoxicillin: Targeting Multidrug-Resistant Gram-Positive Pathogens Staphylococcus aureus and Staphylococcus pseudintermedius in Canine Clinical Isolates

The rising threat of antimicrobial resistance (AMR) is a global concern in both human and veterinary medicine, with multidrug-resistant (MDR) pathogens such as Staphylococcus aureus and Staphylococcus pseudintermedius presenting significant challenges. Background/Objectives: This study evaluates the effectiveness of amoxicillin against these MDR pathogens in canine isolates using pharmacokinetic and pharmacodynamic parameters. Methods: Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and mutation prevention concentration (MPC) were assessed. Additionally, time-kill assays and post-antibiotic effect (PAE) assessments were performed. Epidemiological cutoff (ECOFF) values were established for both species to guide therapy. Results: S. aureus had a higher resistance rate (35.89%) than S. pseudintermedius (15.27%), with MIC50 values of 0.50 μg/mL and 0.25 μg/mL, respectively. The MPC analysis revealed that S. pseudintermedius required higher antibiotic concentrations (16.11 μg/mL) to prevent mutations compared to S. aureus (2.20 μg/mL). Time-kill assays indicated that higher amoxicillin dosages caused faster bacterial reduction. The PAE analysis showed extended post-treatment bacterial suppression at elevated doses, particularly against S. aureus. Conclusions: Species-specific amoxicillin dosing strategies are necessary due to differing resistance and susceptibility profiles between S. aureus and S. pseudintermedius. High-dose amoxicillin therapy is recommended to achieve optimal therapeutic outcomes for resistant SA, while slightly adjusted dosing can manage S. pseudintermedius infections. These findings provide essential insights for veterinary antimicrobial stewardship, underscoring the need for tailored therapeutic approaches to minimize AMR development while ensuring effective infection control.

Phytochemical Analysis and Antimicrobial Activity of Terminalia bellirica (Gaertn.) Roxb. and Terminalia chebula Retz. Fruit Extracts Against Gastrointestinal Pathogens: Enhancing Antibiotic Efficacy

Terminalia bellirica (Gaertn) Roxb. and Terminalia chebula Retz. are significant botanicals in ancient Ayurvedic medicine. They are renowned for their therapeutic properties, notably in addressing gastrointestinal (GI) diseases. These plants have undergone thorough examination related to their antibacterial, anti-inflammatory, and antioxidant properties, which make them highly efficient natural treatments for controlling gastrointestinal infections. The current research demonstrated the antibacterial efficacy of fruit extracts of Terminalia bellirica and Terminalia chebula against Bacillus cereus, Shigella sonnei, Shigella flexneri, and Salmonella typhimurium. We performed disc diffusion and liquid microdilution experiments to evaluate the antibacterial efficacy. All extracts of Terminalia bellirica and Terminalia chebula showed good antibacterial effects against B. cereus and S. flexneri. The minimum inhibitory concentration (MIC) values ranged from 94 µg/mL to 556 µg/mL. The methanolic extracts from both plants also showed noteworthy antibacterial activity against S. sonnei and S. typhimurium, with MIC values of 755 µg/mL for both. Fractional inhibitory concentration studies revealed additive interactions between some conventional antibiotics and the plant extracts when used concurrently. Liquid chromatography-mass spectrometry (LC-MS) analyses revealed that the T. bellirica and T. chebula extracts contained various tannins including methyl gallate, propyl gallate, gallic acid, and ellagic acid. Lethality assays conducted using Artemia franciscana Kellogg nauplii indicated that all the plant extracts are non-toxic. The antibacterial properties and absence of toxicity in T. bellirica and T. chebula fruit extracts indicate their potential for antibiotic development, warranting additional mechanistic and phytochemical studies.

Time-Kill Curve Analysis of Fucoidan Combination with Conventional Antibiotics against Biofilms Formation of Methicillin-Resistant Staphylococcus aureus and Acinetobacter baumannii Clinical Isolates

INTRODUCTION

This study investigates the efficacy of fucoidan combination with antibiotics, against single-species biofilms and mixed-species, individual planktonic, and coculture planktonic conditions of Methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii by time-kill curve analysis.

MATERIALS AND METHODS

Fucoidan, a sulfated polysaccharide, was purchased from Sigma-Aldrich, USA. Clinical isolates of MRSA and A. baumannii from diabetic foot ulcers (DFUs) were used, and single-species biofilms and mixed-species biofilms were developed to assess susceptibility to the treatments using MIC, MBC, minimum biofilm inhibitory concentration, minimum biofilm eradication concentration, and time-kill kinetics assays. Cytotoxicity was assessed using MTT assays on human skin fibroblast cells (HSF-PI 16).

RESULTS

The study determined the geometric mean MIC and MBC values for gentamicin, imipenem, and fucoidan in MRSA and A. baumannii cultures, both individually and in co-cultures. The MIC and MBC values were significantly lower under co-culture conditions, indicating enhanced antimicrobial efficacy. Synergy between fucoidan, gentamicin, and imipenem was confirmed through time-kill assays, which showed complete inhibition of bacterial growth and effective biofilm eradication, particularly in mixed-species biofilms. Fucoidan demonstrated low cytotoxicity at optimal concentrations, highlighting their potential as a therapeutic strategy against biofilm-associated infections in DFUs.

CONCLUSION

The study concludes that fucoidan, in combination with gentamicin and imipenem, effectively disrupts mixed-species biofilms of MRSA and A. baumannii, suggesting fucoidan-based therapies could improve outcomes for DFU patients, warranting further clinical investigation.

Polyphenolic extracts from Diospyros kaki and Vitis vinifera by-products stimulate cytoprotective effects in bacteria-cell host interactions by mediation of transcription factor Nrf2

BACKGROUND

The intestinal and skin epithelium play a strong role against bacterial stimuli which leads to inflammation and oxidative stress when overwhelmed. Polyphenols from fruit-rich diets and by-products show promise against bacterial deleterious effects; however, their antibacterial and health-promoting effects remain understudied.

PURPOSE

This study aimed to assess the impact of polyphenolic extracts of grape (GrPE), persimmon (PePE) and pomegranate (PoPE) by-products on bacterial pathogen-host interactions, focusing beyond growth inhibition to explore their effects on bacterial adhesion, invasion, and modulation of host responses.

METHODS

The microdilution method, as well as the tetrazolium based MTT cell proliferation and cytotoxicity assay with crystal violet staining were used to identify extracts sub-inhibitory concentrations that interfere with bacterial adhesion, invasion or lipopolysaccharides (LPS) effect on cell hosts without compromising host viability. The cytoprotective effects of extracts were assessed in a knock-down model of nuclear factor erythroid 2-related factor 2 (Nrf2).

RESULTS

All extracts demonstrated significant reductions in pathogen adhesion to Caco-2 and HaCaT cells while preserving cellular integrity. Notably, PePE exhibited specific efficacy against Salmonella enterica adhesion, attributed mostly to its gallic acid content, whereas PoPE reduced S. enterica invasion in Caco-2 cells. The extracts supported the prevalence of non-pathogenic and commensal strains of intestinal and skin surfaces, selectively reducing pathogenic adhesion. The extracts mitigated the oxidative stress, enhanced the barrier function, and modulated the pro-inflammatory cytokines in LPS-challenged cells. GrPE, rich in anthocyanins, and PePE were found to mediate their protective effects through Nrf2 activation, while PoPE exerted multifaceted actions independent of Nrf2.

CONCLUSION

Our results highlight the therapeutic potential of GrPE, PePE, and PoPE in shaping bacterial-host interactions, endorsing their utility as novel nutraceuticals for both oral and topical applications to prevent potential bacterial infections through innovative mechanisms.

Enhancing antibacterial efficacy through macrocyclic host complexation of fluoroquinolone antibiotics for overcoming resistance

The use of supramolecular assemblies in pharmaceuticals has garnered significant interest. Recent studies have shown that the activities of antibacterial agents can be enhanced through complexation with cyclic oligomers and metal ions. Notably, these complexes sometimes possess greater therapeutic properties than the parent drugs. To develop microbiologically potent supramolecular drugs, the complexation of macrocyclic hosts with fluoroquinolone (FQ) antibiotics was investigated. FQs are a successful family of antibiotics that target the bacterial enzymes DNA gyrase and DNA topoisomerase IV, leading to bacterial cell death through the inhibition of DNA synthesis. However, antibiotic resistance resulting from the repeated use of FQs over time has limited their effectiveness against resistant pathogens. To overcome this issue, the encapsulation of FQs in polyphenolic macrocycles was investigated. This study highlights resorcinarene, a polyphenolic host with antibacterial properties, and its ability to chemically interact with FQs. The inclusion complexation process was analyzed using NMR and FTIR techniques. The binding constants determined by 1H-NMR titration revealed that levofloxacin forms more stable complexes with resorcinarene than with β-cyclodextrin, which aligned with MD simulations. Assessment of the geometric characteristics of the inclusion complexes using 2D NMR analysis confirmed that different moieties of various FQs can fit into a single host cavity and improve activity against gram-negative bacteria. Overall, these findings suggest that encapsulation in polyphenolic macrocycles is a promising strategy for utilizing FQs against antibiotic-resistant bacteria.

Battling Salmonella enteritidis infections: integrating proteomics and in vivo assessment of Galla Chinensis tannic acid

Salmonella infections pose a significant threat to animal and human health. Phytochemicals present a potential alternative treatment. Galla chinensis tannic acid (GCTA), a hydrolyzable polyphenolic compound, inhibits bacterial growth and demonstrates potential as an alternative or supplement to antibiotics to prevent Salmonella infections. However, little is known about the antimicrobial mechanism of GCTA against Salmonella. Here, we revealed 456 differentially expressed proteins upon GCTA treatment, impacting pathways related to DNA replication, repair, genomic stability, cell wall biogenesis, and lipid metabolism using TMT-labeled proteomic analysis. TEM analysis suggested altered bacterial morphology and structure post-treatment. A Salmonella-infected-mouse model indicated that GCTA administration improved inflammatory markers, alleviated intestinal histopathological alterations, and reduced Salmonella enterica serovar Enteritidis (S. Enteritidis) colonization in the liver and spleen of Salmonella-infected mice. The LD50 of GCTA was 4100 mg/kg with an oral single dose, vastly exceeding the therapeutic dose. Thus, GCTA exhibited antibacterial and anti-infective activity against S. Enteritidis. Our results provided insight into the molecular mechanisms of these antibacterial effects, and highlights the potential of GCTA as an alternative to antibiotics.

Polyphenols and CRISPR as Quorum Quenching Agents in Antibiotic-Resistant Foodborne Human Pathogens (Salmonella Typhimurium, Campylobacter jejuni and Escherichia coli 0157:H7)

Antibiotic resistance in foodborne pathogens is an increasing threat to global human health. Among the most prevalent antibiotic-resistant bacteria are Salmonella enterica serovar Typhimurium, Campylobacter jejuni and E. coli 0157:H7. Control of these and other pathogens requires innovative approaches, i.e., discovering new molecules that will inactivate them, or render them less virulent without inducing resistance. Recently, several polyphenol molecules have been shown to possess such characteristics. Also, the use of CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) approaches has recently been proposed for such purpose. This review summarizes the main findings regarding the application of both approaches to control the above-mentioned foodborne pathogens by relying on Quorum Sensing interference (Quorum Quenching) mechanisms and highlights the avenues needed for further research.

Polyphenols and CRISPR as Quorum Quenching Agents in Antibiotic-Resistant Foodborne Human Pathogens (Salmonella Typhimurium, Campylobacter jejuni and Escherichia coli 0157:H7)

Antibiotic resistance in foodborne pathogens is an increasing threat to global human health. Among the most prevalent antibiotic-resistant bacteria are Salmonella enterica serovar Typhimurium, Campylobacter jejuni and E. coli 0157:H7. Control of these and other pathogens requires innovative approaches, i.e., discovering new molecules that will inactivate them, or render them less virulent without inducing resistance. Recently, several polyphenol molecules have been shown to possess such characteristics. Also, the use of CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) approaches has recently been proposed for such purpose. This review summarizes the main findings regarding the application of both approaches to control the above-mentioned foodborne pathogens by relying on Quorum Sensing interference (Quorum Quenching) mechanisms and highlights the avenues needed for further research.

Unveiling the Potential Ways to Apply Citrus Oil to Control Causative Agents of Pullorum Disease and Fowl Typhoid in Floor Materials

This study investigates the potential role of Cold-pressed Valencia Terpeneless citrus oil (CO), as a natural antimicrobial, in controlling causative agents of pullorum disease and fowl typhoid in floor materials for poultry farming, specifically wooden chips. The study addresses the issues that have arisen as a result of the reduction in antibiotic use in poultry farming, which has resulted in the re-emergence of bacterial diseases including salmonellosis. CO efficiently inhibits the growth of pathogens including various serovars of Salmonella enterica (SE), including SE serovar Gallinarum (S. Gallinarum) and SE serovar Pullorum (S. Pullorum), in a dose-dependent manner. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of CO showed potential for controlling diverse S. Gallinarum and S. Pullorum isolates. Growth inhibition assays demonstrated that 0.4% (v/w) CO eliminated S. Pullorum and S. Gallinarum from 24 h onwards, also impacting poultry gut microbiota and probiotic strains. Floor material simulation, specifically wooden chips treated with 0.4% CO, confirmed CO's effectiveness in preventing S. Gallinarum and S. Pullorum growth on poultry house floors. This study also investigated the effect of CO on the expression of virulence genes in S. Gallinarum and S. Pullorum. Specifically, the study revealed that the application of CO resulted in a downregulation trend in virulence genes, including spiA, invA, spaN, sitC, and sifA, in both S. Pullorum and S. Gallinarum, implying that CO may alter the pathogenicity of these bacterial pathogens. Overall, this study reveals that CO has the potential to be used as a natural antimicrobial in the prevention and management of Salmonella-related infections in chicken production, offering a viable alternative to control these re-emerging diseases.

Pyrogallol impairs staphylococcal biofilm formation via induction of bacterial oxidative stress

AIMS

To examine the effect of the phenolic compound pyrogallol on staphylococcal biofilm formation.

METHODS AND RESULTS

In crystal violet biofilm assays, pyrogallol-reduced biofilm formation in Staphylococcus epidermidis ATCC 35984, Staph. epidermidis NRRL-B41021, Staphylococcus aureus USA300, and Staph. aureus Newman, without significantly impairing bacterial viability. Pyrogallol-mediated impairment of biofilm formation was likely due to induction of bacterial oxidative stress, as its effect was greater in catalase-deficient versus WT Staph. aureus, and biofilm production was rescued by exogenous catalase. The effect of pyrogallol on staphylococcal biofilm formation mirrored that of the known oxidant hydrogen peroxide, which also reduced biofilm formation in a dose-dependent manner.

CONCLUSIONS

Pyrogallol reduces biofilm formation in S. aureus and Staph. epidermidis in a mechanism involving induction of bacterial oxidative stress.

Engineer a double team of short-lived and glucose-sensing bacteria for cancer eradication

Rationally designed and engineered bacteria represent an emerging unique approach for cancer treatment. Here, we engineer a short-lived bacterium, mp105, that is effective against diverse cancer types and safe for intravenous administration. We reveal that mp105 combats cancer by direct oncolysis, depletion of tumor-associated macrophages, and elicitation of CD4⁺ T cell immunity. We further engineer a glucose-sensing bacterium named m6001 that selectively colonizes solid tumors. When intratumorally injected, m6001 clears tumors more efficiently than mp105 due to its post-delivery replication in tumors and potent oncolytic capacity. Finally, we combine intravenous injection of mp105 and intratumoral injection of m6001, forming a double team against cancer. The double team enhances cancer therapy compared with single treatment for subjects carrying both intratumorally injectable and uninjectable tumors. The two anticancer bacteria and their combination are applicable to different scenarios, turning bacterial therapy for cancer into a feasible solution.

The genetic response of Salmonella Typhimurium during trans-cinnamaldehyde assisted heat treatment and its correlation with bacterial resistance in different low moisture food components

Our previous study found that water activity (a_w)- and matrix-dependent bacterial resistance wasdeveloped in Salmonella Typhimurium during antimicrobial-assisted heat treatment in low moisture foods (LMFs) matrices. To better understand the molecular mechanism behind the observed bacterial resistance, gene expression analysis was conducted on S. Typhimurium adapted to different conditions with or without the trans-cinnamaldehyde (CA)-assisted heat treatment via quantitative polymerase chain reaction (qPCR). Expression profiles of nine stress-related genes were analyzed. The upregulation of rpoH and dnaK and downregulation of ompC were observed during bacterial adaptation in LMF matrices and the combined heat treatment, which likely contributed to the bacterial resistance during the combined treatment. Their expression profiles were partially consistent with the previously-observed effect of a_w or matrix on bacterial resistance. The upregulation of rpoE, otsB, proV, and fadA was also observed during adaptation in LMF matrices and might contribute to desiccation resistance, but likely did not contribute to bacterial resistance during the combined heat treatment. The observed upregulation of fabA and downregulation of ibpA could not be directly linked to bacterial resistance to either desiccation or the combined heat treatment. The results may assist the development of more efficient processing methods against S. Typhimurium in LMFs.

Biochemical and molecular mechanisms of antibiotic resistance in Salmonella spp

Salmonella is a diverse Gram-negative bacterium that represents the major disease burden worldwide. According to WHO, Salmonella is one of the fourth global causes of diarrhoeal disease. Antibiotic resistance is a worldwide health concern, and Salmonella spp. is one of the microorganisms that can evade the toxicity of antimicrobials via antibiotic resistance. This review aims to deliver in-depth knowledge of the molecular mechanisms and the underlying biochemical alterations perceived in antibiotic resistance in Salmonella. This information will help understand and mitigate the impact of antibiotic-resistant bacteria on humans and contribute to the state-of-the-art research developing newer and more potent antibiotics.

A comprehensive review on natural phenolic compounds as alternatives to in-feed antibiotics

Intensive livestock and poultry farming in China largely relied on the use of in-feed antibiotics until July 2020. The consequences of antibiotic overuse in animal feed include accumulation in animal products and the development of bacterial antibiotic resistance, both of which threaten food safety and human health. China has now completely banned the circulation of commercial feed containing growth-promoting drug additives (except Chinese herbal medicine). Therefore, alternatives to in-feed antibiotics in animal production are greatly needed. Natural phenolic compounds (NPCs) exist widely in plants and are non-toxic, non-polluting, highly reproducible, and leave little residue. Many natural flavonoids, phenolic acids, lignans, and stilbenes have polyphenol chemical structures and exhibit great potential as alternatives to antibiotics. In this review we delineate the characteristics of plant-derived NPCs and summarize their current applications as alternatives to in-feed antibiotics, aiming to provide new strategies for antibiotic-free feeding and promote the development of more sustainable animal husbandry practices.

Cytokines and cecal microbiome modulations conferred by a dual vaccine in Salmonella-infected layers

Zoonotic Salmonella infection is a critical and challenging issue for public health. Since human infections are mainly associated with consuming contaminated chicken products, strategies to reduce Salmonella carriage and shedding are essential. Here we investigate the mechanisms of the live attenuated Salmonella vaccine (AviPro Salmonella Duo) against Salmonella Enteritidis (SE) infection. We focused on inflammatory-related cytokine expressions and cecal microbiota modulations in specific-pathogen-free (SPF) and field layers. Forty-eight 2-day-old SPF layers were randomly allotted into S.SEvc, S.SEc, S.Vc, and S.Ct groups in trial 1. The equal number of filed layers at 25 wk were allocated into SEvc, SEc, Vc, and Ct groups in trial 2. Each group contained 12 layers. Groups were further assigned for vaccination (S.Vc and Vc groups), SE challenge (S.SEc and SEc groups), vaccination and the following SE challenge (S.SEvc and SEvc groups), or the placebo treatment (S.Ct and Ct groups). Cecal tissues and contents of layers on day 14 post-SE-challenges were collected for cytokine mRNA expression and 16S rRNA metagenomic analyses. We found that SE challenges significantly upregulated expressions of IFNγ, IL-1β, IL-12β, and NFκB1A in SPF layers. The vaccine notably counteracted the levels of IFNα, IFNγ, and NFκB1A activated by SE attacks. The vaccination, SE challenge, and their combination did not significantly affect alpha diversities but promoted dissimilarities in microbial communities between groups. Eubacterium_coprostanoligenes and Faecalibacterium_prausnitzii were identified as contributory taxa in the cecal microbiota of SE-challenged and vaccinated SPF layers. A significantly higher abundance of Faecalibacterium_prausnitzii in the ceca further correlated with the vaccination conferred protection against SE infection. In contrast, Oscillibacter_valericigenes and Mediterraneibacter_glycyrrhizinilyticus were featured taxa in Salmonella-infected field layers. Megamonas_hypermegale and Megamonas_rupellensis were identified as featured taxa in vaccinated field layers compared to SE-infected layers. To conclude, applying a dual Salmonella vaccine in this study modulated expressions of inflammatory-related cytokines and the cecal microbiome in layers, contributing to protection against SE infection. The feature microbes are promising for developing predictive indices and as antibiotic alternatives added to feed to reduce the risk of Salmonella shedding and contamination.

A pharmacodynamic investigation to assess the synergism of orbifloxacin and propyl gallate against Escherichia coli

Escherichia coli (E. coli) infections are becoming increasingly difficult to treat, as antibiotic-resistant variants proliferate. Studies on novel methods to combat the spread of resistance and improve the performance of current antibiotics are vital. We aimed to boost the efficacy of the antibiotic orbifloxacin (ORB) against E. coli by combining it with a phenolic component, propyl gallate (PG). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ORB against the E. coli KVCC 1423 resistant strain were 128 μg/ml and 256 μg/ml, respectively. However, the MIC of ORB for the remaining E. coli strains was 0.5 μg/ml–2 μg/ml. For the combination of PG and ORB, the lowest fractional inhibitory concentration (FIC) index was less than 0.5, and the combination decreased the MIC of both drugs by 74%. The time-kill assay revealed the killing properties of both the drugs and the pharmacodynamic model (PD model) confirmed the strong killing properties of the combination as compared to the individual activities of the drugs. The ratio between MIC and mutant prevention concentration of ORB against E. coli 1400306 and 1,423 were 1:32 and 1:8, respectively. The combination of ORB and PG showed strong biofilm eradication and inhibited the motility of bacteria. The cell viability of the combination was > 80%. Therefore, we believe that ORB and PG in combination could be a possible antibacterial candidate that could minimize resistance and improve antibiotic potential.

Chemistry and Bioactivity of Microsorum scolopendria (Polypodiaceae): Antioxidant Effects on an Epithelial Damage Model

Microsorum scolopendia (MS), which grows on the Chilean island of Rapa Nui, is a medicinal fern used to treat several diseases. Despite being widely used, this fern has not been deeply investigated. The aim of this study was to perform a characterization of the polyphenolic and flavonoid identity, radical scavenging, antimicrobial, and anti-inflammatory properties of MS rhizome and leaf extracts (RAE and HAE). The compound identity was analyzed through the reversed-phase high-performance liquid chromatography (RP-HPLC) method coupled with mass spectrometry. The radical scavenging and anti-inflammatory activities were evaluated for DPPH, ORAC, ROS formation, and COX inhibition activity assay. The antimicrobial properties were evaluated using an infection model on Human Dermal Fibroblast adult (HDFa) cell lines incubated with Staphylococcus aureus and Staphylococcus epidermidis. The most abundant compounds were phenolic acids between 46% to 57% in rhizome and leaf extracts, respectively; followed by flavonoids such as protocatechic acid 4-O-glucoside, cirsimaritin, and isoxanthohumol, among others. MS extract inhibited and disaggregated the biofilm bacterial formed and showed an anti-inflammatory selective property against COX-2 enzyme. RAE generated a 64% reduction of ROS formation in the presence of S. aureus and 87.35% less ROS in the presence of S. epidermidis on HDFa cells. MS has great therapeutic potential and possesses several biological properties that should be evaluated.

Insight into the synergistic adsorption-reduction character of chromium(VI) onto poly(pyrogallol-tetraethylene pentamine) microsphere in synthetic wastewater

Facile fabrication of the ultra-high-performance adsorbent can effectively ameliorate the Cr(VI)-pollution elimination in sewage control. Herein, a simple synthesis strategy is proposed to tap a versatile chelating resin poly(pyrogallol-tetraethylene pentamine) (PPTA) with respect to Cr(VI) removal from solution. Multiple changing factors which affect the adsorption behavior of PPTA are explored sequentially, such as initial pH, adsorbate concentration, adsorbent dosage, temperature, foreign ions, etc. The microstructure and functional mechanism of synthetic adsorbent are investigated systematically by means of various characterizations including TEM, EDS, FT-IR, XPS, etc. Consequently, the as-prepared PPTA-3 microsphere by reactant ratio of 1: 1 represents a brilliant synergistic adsorption and reduction result for Cr(VI) by the drastic electrostatic interaction of -NH₃⁺ and -OH₂⁺ groups, including satisfactory removal efficiency which closes to 100 % in low concentration, favorable specificity for the influence from coexistent ions (Mo(VI), Mn(VII), Cl^-, Cr(III), etc), and passable recyclability. Following the surpassingly fitting with Langmuir isotherm model, its maximum capacity reaches 714.29 mg g^-1 at 30 °C. The removal performance is essentially in agreement with the pseudo-second-order kinetics, simultaneously, suffers the rate-limiting impact depending on intra-particle diffusion process. In brief, this newly developed chelating resin presents an effective means with regard to the Cr(VI)-wastewater treatment or other uses in the future.

Pyrogallol and Fluconazole Interact Synergistically In Vitro against Candida glabrata through an Efflux-Associated Mechanism

Candida glabrata is currently the first or second most commonly encountered non-albicans Candida species worldwide. The potential severity of Candida resistance mandates the discovery of novel antifungal agents, including those that can be used in combination therapies. In this study, we evaluated the in vitro interactions of pyrogallol (PG) and azole drugs against 22 clinical C. glabrata isolates. The potential mechanism underlying the synergism between PG and fluconazole (FLC) was investigated by the rhodamine 6G efflux method and quantitative reverse transcription (qRT)-PCR analysis. In susceptibility tests, PG showed strong synergism with FLC, itraconazole (ITC), and voriconazole (VRC), with fractional inhibitory concentration index values of 0.18 to 0.375 for PG+FLC, 0.250 to 0.750 for PG+ITC, and 0.141 to 0.750 for PG+VRC. Cells grown in the presence of PG+FLC exhibited reduced rhodamine 6G extrusion and significantly downregulated expression of the efflux-related genes CgCDR1, CgCDR2, and CgPDR1 compared with cells grown in the presence of PG or FLC alone. PG did not potentiate FLC when tested against a ΔCgpdr1 strain. Restoration of a functional CgPDR1 allele also restored the synergism. These results indicate that PG is an antifungal agent that synergistically potentiates the activity of azoles. Furthermore, PG appears to exert its effects by inhibiting efflux pumps and downregulating CgCDR1, CgCDR2, and CgPDR1, with CgPDR1 probably playing a crucial role in this process.