Bacterial Suppression Research Articles

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.

Pharmacokinetic/pharmacodynamic analysis of meropenem and fosfomycin combinations in in vitro time-kill and hollow-fibre infection models against multidrug-resistant and carbapenemase-producing Klebsiella pneumoniae.

MDR Gram-negative bacteria, such as ESBL-producing and carbapenemase-producing Klebsiella pneumoniae, represent major global health threats. Treatment options are limited due to increasing resistance and slowed development of novel antimicrobials, making it necessary to apply effective combination therapies based on approved antibiotics. To quantitatively evaluate the synergistic potential of meropenem and fosfomycin against carbapenem-resistant K. pneumoniae strains isolated from clinics. We evaluated four MDR K. pneumoniae strains, each expressing KPC-2 or KPC-3, using static time-kill assays that accounted for measured meropenem degradation. This was followed by pharmacokinetic/pharmacodynamic (PK/PD) interaction modelling, which estimated meropenem degradation rate constants and identified perpetrator-victim relationships in PD interactions. Dynamic hollow-fibre infection model (HFIM) experiments were used to confirm synergy. Static time-kill assays demonstrated high killing effects and suppressed regrowth for the combination of meropenem and fosfomycin, compared with the failure of monotherapy. Meropenem degradation was significantly higher in the presence of bacteria, attributable to carbapenemase activity. Pharmacometric models indicated a synergistic interaction primarily driven by meropenem as the perpetrator, enhancing the potency of fosfomycin. HFIM experiments confirmed in vitro synergy, demonstrating continuous bacterial suppression of the combination therapy. Meropenem and fosfomycin exhibited additive or synergistic potential against carbapenemase-expressing single- or double-resistant K. pneumoniae at clinically achievable concentrations. This combination therapy may offer a strategy against MDR infections, possibly improving clinical treatment outcomes. Further in vivo research is needed to translate these findings into clinical practice, emphasizing the importance of PK/PD modelling in rationalizing antibiotic use.

Mesomycoplasma (Mycoplasma) ovipneumoniae dihydrolipoamide dehydrogenase is an immunogenic plasminogen binding protein and a putative adhesin

The interaction of Mesomycoplasma (Mycoplasma) ovipneumoniae (M. ovipneumoniae) with host cells is a pivotal step in the infection process, underlining the necessity to develop vaccines and therapeutic approaches targeting the pathogen's key invasion mechanisms. The bacterium's capacity for adherence, invasion, and subsequent evasion of the host immune response underpins its pathogenicity, rendering adherence genes feasible vaccine targets. This study focuses on pyruvate dehydrogenase complex component E3 (PdhD), a membrane-anchored surface protein implicated in these pathogenic processes. Bioinformatics analysis reveals the conservation of PdhD sequence within M. ovipneumoniae. Membrane protein extraction, immunoblotting and ELISA assay have confirmed the presence of PdhD on the M. ovipneumoniae surface and cytoplasm, suggesting its multifunctionality. Our research employed antibody inhibition assays to characterize the bacterial adhesion suppression by anti-PdhD antibodies, complemented by bactericidal complement assays, supporting its candidacy as a putative vaccine target. The ELISA binding assay substantiated that PdhD binded to plasminogen (Plg) in a dose-dependent manner. Notably, PdhD is also involved in biofilm formation. The inhibitory effect of anti-PdhD sera on biofilm formation is congruent with novel therapeutic strategies targeting related mycoplasmas. This study reports the characterization of the first virulence-associated protein PdhD of M. ovipneumoniae and suggests its potential as a vaccine target to combat M. ovipneumoniae infection.

Therapeutic Interventions for Pseudomonas Infections in Cystic Fibrosis Patients: A Review of Phase IV Trials.

Pseudomonas aeruginosa (Pa) poses a significant threat to individuals with cystic fibrosis (CF), as this bacterium is highly adaptable and resistant to antibiotics. While early-stage Pa infections can often be eradicated with aggressive antibiotic therapy, chronic infections are nearly impossible to eliminate and require treatments that focus on long-term bacterial suppression. Without such suppression, these persistent infections can severely damage the lungs, leading to serious complications and a reduced life expectancy for CF patients. Evidence for a specific treatment regimen for managing Pa infections in CF patients remains limited. This narrative review provides a detailed analysis of antimicrobial therapies assessed in completed phase IV trials, focusing on their safety and efficacy, especially with prolonged use. Key antibiotics, including tobramycin, colistin, meropenem, aztreonam, ceftolozane/tazobactam, ciprofloxacin, and azithromycin, are discussed, emphasizing their use, side effects, and delivery methods. Inhaled antibiotics are preferred for their targeted action and minimal side effects, while systemic antibiotics offer potency but carry risks like nephrotoxicity. The review also explores emerging treatments, such as phage therapy and antibiofilm agents, which show promise in managing chronic infections. Nonetheless, further research is necessary to enhance the safety and effectiveness of existing therapies while investigating new approaches for better long-term outcomes.

Targeting Pseudomonas aeruginosa biofilm with an evolutionary trained bacteriophage cocktail exploiting phage resistance trade-offs

Spread of multidrug-resistant Pseudomonas aeruginosa strains threatens to render currently available antibiotics obsolete, with limited prospects for the development of new antibiotics. Lytic bacteriophages, the viruses of bacteria, represent a path to combat this threat. In vitro-directed evolution is traditionally applied to expand the bacteriophage host range or increase bacterial suppression in planktonic cultures. However, while up to 80% of human microbial infections are biofilm-associated, research towards targeted improvement of bacteriophages’ ability to combat biofilms remains scarce. This study aims at an in vitro biofilm evolution assay to improve multiple bacteriophage parameters in parallel and the optimisation of bacteriophage cocktail design by exploiting a bacterial bacteriophage resistance trade-off. The evolved bacteriophages show an expanded host spectrum, improved antimicrobial efficacy and enhanced antibiofilm performance, as assessed by isothermal microcalorimetry and quantitative polymerase chain reaction, respectively. Our two-phage cocktail reveals further improved antimicrobial efficacy without incurring dual-bacteriophage-resistance in treated bacteria. We anticipate this assay will allow a better understanding of phenotypic-genomic relationships in bacteriophages and enable the training of bacteriophages against other desired pathogens. This, in turn, will strengthen bacteriophage therapy as a treatment adjunct to improve clinical outcomes of multidrug-resistant bacterial infections.

Formulation of different concentrations of nanosilver fluoride incorporated dentifrices, evaluation of its cytotoxicity and antimicrobial effect on Streptococcus mutans.

Dental caries is a prevalent oral health issue primarily caused by Streptococcus mutans, a bacterium that contributes to tooth decay. Antimicrobial agents in dentifrices are often utilized to target these pathogens. Nano silver fluoride (NSF) has emerged as a potential antimicrobial agent due to its ability to inhibit bacterial growth. This study aims to investigate the antimicrobial efficacy and cytotoxicity of dentifrices containing varying concentrations of NSF against Streptococcus mutans. The primary aim of this study was to evaluate the antimicrobial effectiveness of Nano silver fluoride-incorporated dentifrices against Streptococcus mutans and assess their cytotoxic effects on mammalian cells. To synthesize and characterize nano silver particles using transmission electron microscopy (TEM).To determine the antimicrobial activity of NSF dentifrices at different concentrations using the agar well diffusion method. To assess the cytotoxicity of NSF dentifrices on RAW 264.7 mouse macrophage cells using the MTT assay. Synthesis and Characterization: Nano silver particles were synthesized through a chemical reduction process, resulting in particles with sizes ranging between 40-50 nm, confirmed via TEM analysis. Preparation of Dentifrice: Various concentrations of Nano silver fluoride (0%, 0.65%, 1.25%, 2.5%, and 5%) were incorporated into a dentifrice base. Antimicrobial Testing: The antimicrobial efficacy of the NSF dentifrices was assessed using the agar well diffusion method, where the zone of inhibition around each well was measured to evaluate bacterial growth suppression. Cytotoxicity Assessment: Cytotoxicity was analyzed using the MTT assay on RAW 264.7 mouse macrophage cells, with NSF concentrations ranging from 0.156% to 10% to determine their impact on cell viability. The study demonstrated that dentifrices containing NSF showed significant antimicrobial activity against Streptococcus mutans, with a dose-dependent increase in the zone of inhibition. Higher concentrations of NSF were associated with larger zones of bacterial inhibition. A one-way ANOVA revealed statistically significant differences between various concentrations, with post hoc Bonferroni tests confirming significant differences between specific pairs. In terms of cytotoxicity, a dose-dependent decrease in cell viability was observed with increasing concentrations of NSF. The lowest concentration (0.156% NSF) had the highest cell viability (86.67%), while the highest concentration tested (10% NSF) resulted in minimal cell viability (0.68%). The study concludes that NSF-incorporated dentifrices exhibit promising antimicrobial efficacy against Streptococcus mutans in a concentration-dependent manner. However, increasing concentrations of NSF also correlated with higher cytotoxicity levels in mammalian cells. Therefore, optimizing the concentration of NSF in dentifrices is crucial to balance antimicrobial benefits with biocompatibility.

Enhanced Suppression of Stenotrophomonas maltophilia by a Three-Phage Cocktail: Genomic Insights and Kinetic Profiling.

In our era of rising antibiotic resistance, Stenotrophomonas maltophilia (STM) is an understudied, gram-negative, aerobic bacterium widespread in the environment and increasingly causing opportunistic infections. Treating STM infections remains difficult, leading to an increase in disease severity and higher hospitalization rates in people with Cystic Fibrosis (pwCF), cancer, and other immunocompromised health conditions. The lack of effective antibiotics has led to renewed interest in phage therapy; however, there is a need for well-characterized phages. In response to an oncology patient with a respiratory infection, we collected 18 phages from Southern California wastewater influent that exhibit different plaque morphology against STM host strain B28B, cultivated from a blood sample. Here, we characterize the genomes and life cycle kinetics of our STM phage collection. We hypothesize that genetically distinct phages give rise to unique lytic life cycles that can enhance bacterial killing when combined into a phage cocktail compared to the individual phages alone. We identified three genetically distinct clusters of phages, and a representative from each group was screened for potential therapeutic use and investigated for infection kinetics. The results demonstrated that the three-phage cocktail significantly suppressed bacterial growth compared to individual phages when observed for 48 hours. We also assessed the lytic impacts of our three-phage cocktail against a collection of 46 STM strains to determine if a multi-phage cocktail can expand the host range of individual phages. Our phages remained strain-specific and infect >50% of tested strains. The multi-phage cocktail maintains bacterial growth suppression and prevents the emergence of phage-resistant strains throughout our 40-hour assay. These findings suggest specialized phage cocktails may be an effective avenue of treatment for recalcitrant STM infections resistant to current antibiotics.

Injectable immunoregulatory hydrogels sequentially drive phenotypic polarization of macrophages for infected wound healing

Regulating macrophage phenotypes to reconcile the conflict between bacterial suppression and tissue regeneration is ideal for treating infectious skin wounds. Here, an injectable immunoregulatory hydrogel (SrmE20) that sequentially drives macrophage phenotypic polarization (M0 to M1, then to M2) was constructed by integrating anti-inflammatory components and proinflammatory solvents. In vitro experiments demonstrated that the proinflammatory solvent ethanol stabilized the hydrogel structure, maintained the phenolic hydroxyl group activity, and achieved macrophages' proinflammatory transition (M0 to M1) to enhance antibacterial effects. With ethanol depletion, the hydrogel's cations and phenolic hydroxyl groups synergistically regulated macrophages' anti-inflammatory transition (M1 to M2) to initiate regeneration. In the anti-contraction full-thickness wound model with infection, this hydrogel effectively eliminated bacteria and even achieved anti-inflammatory M2 macrophage accumulation at three days post-surgery, accelerated angiogenesis and collagen deposition. By sequentially driving macrophage phenotypic polarization, this injectable immunoregulatory hydrogel will bring new guidance for the care and treatment of infected wounds.

Efficacy of Bacillus atrophaeus strain RS36 and Priestia megaterium strain RS91 with Partially Reduced Fertilization for Bacterial Leaf Blight Suppression in Rice Seedlings

Efficacy of Bacillus atrophaeus strain RS36 and Priestia megaterium strain RS91 with Partially Reduced Fertilization for Bacterial Leaf Blight Suppression in Rice Seedlings

Heated Aeration for Nitrite-Oxidizing Bacteria (NOB) Control in Anammox-Integrated Membrane-Aerated Biofilm Reactors (MABR)

Nutrient removal in conventional wastewater treatment systems is expensive due to the high aeration costs. An alternative method for effective and sustainable nitrogen removal in wastewater treatment is anaerobic ammonium oxidation (Anammox) implemented with other innovative technologies, such as membrane-aerated biofilm reactors (MABRs). A major challenge associated with the Anammox process is effective control of nitrite-oxidizing bacteria (NOB). High temperature operation in wastewater treatment systems can promote Anammox bacterial growth and inhibit NOB activity. This research aims to investigate the feasibility of integrating Anammox processes with a lab-scale MABR and to examine the effects of high temperature aeration supplied to MABR systems on Anammox bacterial growth and NOB suppression. Experimental results indicate that the membrane’s air permeability was a critical parameter for the successful operation of Anammox-integrated MABR systems due to its influence on the system’s dissolved oxygen concentration (0.41 ± 0.39 mg O2/L). The ammonia removal by AOB and Anammox bacteria was determined to be 7.53 mg N/L·d (76.5%) and 2.12 mg N/L·d (23.5%), respectively. High temperature aeration in MABRs with the Anammox process shows a promising potential for improving energy consumption and sustainable nitrogen removal in wastewater treatment systems.

In vitro evaluation of using ceftazidime/avibactam against carbapenem-resistant Acinetobacter baumannii

ObjectiveCarbapenem-resistant Acinetobacter baumannii (CRAB) is a global concern as effective treatments are very limited. We previously used a modified susceptibility testing approach to predict growth suppression in carbapenem-resistant Enterobacterales, but there are uncertainties about the generalizability of the model. The objective of this study is to verify if a similar approach can be extended to CRAB. MethodA clinical isolate of CRAB resistant to ceftazidime/avibactam (CAZ/AVI, MIC = 32/4 mg/L) was examined. CAZ susceptibility was determined using increasing concentrations of AVI (0–64 mg/L), and MIC reduction was characterized with a sigmoid inhibitory maximum effect (Emax) model. The effectiveness of CAZ/AVI was validated in a hollow fibre infection model (HFIM) over 72 hours, using simulated unbound serum / epithelial lining fluid (ELF) exposures of 2.5 g over 2 hours every 8 hours. Baseline inocula of approximately 5.5 log CFU/mL were examined. ResultsAn AVI concentration-dependent reduction in CAZ MIC was observed (r2 = 0.99). CAZ MIC was dramatically reduced from 512 mg/L (no AVI) to 32 mg/L (AVI = 4 mg/L), and further to 8 mg/L (AVI = 16 mg/L). Pharmacokinetic simulations were satisfactory in the HFIM (r2 > 0.96). Bacterial suppression was observed >24 hours with the serum exposure, but not that from the ELF. ConclusionUsing multiple AVI concentrations within the clinically relevant range, our susceptibility testing approach could have better insights of treatment outcome for infections caused by CRAB. This could potentially lead to effective intervention(s) overlooked by conventional susceptibility testing method. This case highlights the importance of site-specific drug exposures on determining treatment outcome.

Deciphering Aphanomyces euteiches-pea-biocontrol bacterium interactions through untargeted metabolomics

Aphanomyces euteiches causes root rot in pea, leading to significant yield losses. However, the metabolites involved in this pathosystem have not been thoroughly studied. This study aimed to fill this gap and explore mechanisms of bacterial suppression of A. euteiches via untargeted metabolomics using pea grown in a controlled environment. Chemical isotope labeling (CIL), followed by liquid chromatography-mass spectrometry (LC–MS), was used for metabolite separation and detection. Univariate and multivariate analyses showed clear separation of metabolites from pathogen-treated pea roots and roots from other treatments. A three-tier approach positively or putatively identified 5249 peak pairs or metabolites. Of these, 403 were positively identified in tier 1; 940 were putatively identified with high confidence in tier 2. There were substantial changes in amino acid pool, and fatty acid and phenylpropanoid pathway products. More metabolites, including salicylic and jasmonic acids, were upregulated than downregulated in A. euteiches-infected roots. 1-aminocyclopropane-1-carboxylic acid and 12-oxophytodienoic acid were upregulated in A. euteiches + bacterium-treated roots compared to A. euteiches-infected roots. A great number of metabolites were up- or down-regulated in response to A. euteiches infection compared with the control and A. euteiches + bacterium-treated plants. The results of this study could facilitate improved disease management.

Utilization of nanotechnology and experimental design in the development and optimization of a posaconazole‒calendula oil nanoemulgel for the treatment of mouth disorders.

Introduction: Essential oil‒based nanoemulsions (NEs) are the subjects of extensive investigation due to their potential to address a variety of oral health issues. NEs are delivery systems that improve lipid medicine solubility and distribution to intended sites. The goal of the current study was to create and enhance a self-nanoemulsifying drug delivery paradigm based on calendula oil (CO) and decorated with chitosan (CS) that could deliver posaconazole (PSZ) for the treatment of gingivitis. Method: Employing a response-surface Box‒Behnken design, PSZ-CO-CS NEs were created with varying amounts of PSZ (10, 15, and 20mg), percentages of CO (6%, 12%, and 18%), and percentages of CS (0.5%, 1.5%, and 2.5%). Results and conclusion: The optimized formulation resulted in a 22-mm bacterial growth suppression zone, 25-mm fungal growth inhibition zone, droplet sizes of 110nm, and a viscosity of 750 centipoise (cP). Using the appropriate design, the ideal formulation was produced; it contained 20mg of PSZ, 18% of CO, and 1.35% of CS. Furthermore, the optimal formulation had a more controlled drug release, larger inhibition zones of bacterial and fungal growth, and desirable rheologic properties. Additionally, the optimized formulation substantially lowered the ulcer index in rats when tested against other formulations. Thus, this investigation showed that PSZ-CO-CS NEs could provide efficient protection against microbially induced gingivitis.

Bacteriophage and antibiotic combination therapy for recurrent Enterococcus faecium bacteremia.

Phage therapy is an emerging therapeutic approach for treating bacterial infections that do not respond to traditional antibiotics. The addition of phage therapy to systemic antibiotics to treat a patient with recurrent E. faecium infections that were non-responsive to antibiotics alone resulted in fewer hospitalizations and improved the patient's quality of life. Combination phage and antibiotic therapy reduced E. faecium and VRE abundance in the patient's stool. Eventually, an anti-phage antibody response emerged that was able to neutralize phage activity, which may have limited clinical efficacy. This study demonstrates the potential of phages as an additional option in the antimicrobial toolbox for treating invasive enterococcal infections and highlights the need for further investigation to ensure phage therapy can be deployed for maximum clinical benefit.

Disinfection Efficacy of Electrohydraulic Discharge Plasma against Xanthomonas campestris pv campestris: A Sustainable Seed Treatment Approach.

The prevalence of plant diseases caused by pathogens such as Xanthomonas campestris pv campestris (Xcc) poses a significant challenge to sustainable agriculture, necessitating the development of effective and eco-friendly disinfection methods. In this study, we investigated the efficacy of electrohydraulic discharge plasma (EHDP) as a promising alternative for disinfection against Xcc, a pathogen responsible for black rot in cruciferous vegetables. Unlike conventional gas-phase plasma, EHDP introduces two pivotal components: gas-liquid interface plasma (GLIP) and its consequential byproduct, plasma-activated water (PAW). While GLIP enables dual-phase production of reactive oxygen and nitrogen species (RONS), PAW is a reservoir of liquid-phase long-lived RONS, thereby enhancing its bactericidal efficacy. In our evaluations, we tested EHDP-induced GLIP and EHDP-induced PAW against Xcc cells in both in vitro (Xcc suspension) and in vivo (Xcc-inoculated cabbage seeds) settings, achieving noteworthy results. Within 15 min, these methods eliminated ∼98% of the Xcc cells in suspension. For in vivo assessments, nontreated seeds exhibited an infection rate of 98%. In contrast, both EHDP treatments showed a significant reduction, with ∼60% fewer seeds infected while maintaining ∼90% germination rate. In addition, the liquid-phase RONS in EHDP-PAW may enhance seed vigor with a faster germination rate within the initial 5 days. Remarkably, around 90% of EHDP-PAW-treated seeds yielded healthy seedlings, indicating dual benefits in bacterial suppression and seed growth stimulation. In contrast, the percentage of healthy seedlings from nontreated, Xcc-inoculated seeds was approximately 70%. Our research demonstrates the feasibility of using eco-friendly EHDP in the seed disinfection process.

Evolutionary and co-evolutionary phage training approaches enhance bacterial suppression and delay the emergence of phage resistance.

The development of phage resistance by bacteria is a major barrier that impedes the therapeutic use of phages. Phage training has been proposed as a novel tool that harnesses the evolutionary potential of phages to improve phage infectivity. Both evolutionary and co-evolutionary phage training models have been previously reported to train phages. However, both of these phage training models have been reported able to effectively suppress the emergence of phage-resistant bacteria mutants, thus presenting a contradictory phenomenon. Therefore, in this study, we set out to systematically compare the effectiveness of both evolutionary and co-evolutionary phage training models with regard to phage physiology, infectivity, and genotype. To this end, a natural lytic phage capable of infecting a Klebsiella pneumonia strain was isolated from wastewater and subjected to evolutionary and co-evolutionary phage training for 30days. After the phage training, the physiology and genomic characteristics of evolved and co-evolved phages were assessed. Our results demonstrated that both evolved and co-evolved phages exhibit improved bacterial suppression activity and are able to delay the emergence of phage resistance. Furthermore, both phages harbored unique genome mutational changes in different functionally associated phage proteins. Similarly, evolved and co-evolved phage-resistant bacteria mutants that arose post phage infection displayed varying phage resistance sensitivities, which may be correlated to the unique genome mutational change identified in cell membrane structure. In particular, co-evolved phage-resistant bacteria mutants exhibited less phage resistance compared to evolved phage-resistant bacteria mutants. These results highlighted the finding that the co-evolutionary phage training model serves as a better phage training model as it endows phage with improved infectivity, but also selects for phage-resistant bacteria with a lower phage resistance when compared to evolutionary phage training.

Design and synthesis of potential pyrrole-coupled carboxamide derivatives as an anti-superbug MRSA agent

A series of new pyrrole-coupled carboxamide derivatives had been synthesized and amply characterized by various techniques, viz FTIR, 1H-NMR, 13C-NMR, and LCMS. All these compounds had undergone evaluation for their PASS, BBB, pharmacophore model, ADME, and bioactive score. The antibacterial properties of all the derivatives were examined and compound 5i demonstrated strong antibacterial activity against MRSA. A membrane damage investigation supported by SEM pictures, cellular content leakage, potassium efflux, and bacterial respiration suppression showed that compound 5i had anti-MRSA properties. A good binding score of -9.11 was found for compound 5i against the MRSA protein 6FTB in an in silico molecular docking analysis, compared to a score of -10.25 for streptomycin. Based on these findings, compound 5i can be further studied in order to develop it as a drug to treat MRSA infections.

Bacterial Pathogen-Mediated Suppression of Host Trafficking to Lysosomes: Fluorescence Microscopy-Based DQ-Red BSA Analysis.

Intracellular bacterial pathogens have evolved to be adept at manipulating host cellular function for the benefit of the pathogen, often by means of secreted virulence factors that target host pathways for modulation. The lysosomal pathway is an essential cellular response pathway to intracellular pathogens and, as such, represents a common target for bacterial-mediated evasion. Here, we describe a method to quantitatively assess bacterial pathogen-mediated suppression of host cell trafficking to lysosomes, using Salmonella enterica serovar Typhimurium infection of epithelial cells as a model. This live-cell imaging assay involves the use of a BODIPY TR-X conjugate of BSA (DQ-Red BSA) that traffics to and fluoresces in functional lysosomes. This method can be adapted to study infection with a broad array of pathogens in diverse host cell types. It is capable of being applied to identify secreted virulence factors responsible for a phenotype of interest as well as domains within the bacterial protein that are important for mediating the phenotype. Collectively, these tools can provide invaluable insight into the mechanisms of pathogenesis of a diverse array of pathogenic bacteria, with the potential to uncover virulence factors that may be suitable targets for therapeutic intervention. Key features • Infection-based analysis of bacterial-mediated suppression of host trafficking to lysosomes, using Salmonella enterica serovar Typhimurium infection of human epithelial cells as a model. • Live microscopy-based analysis allows for the visualization of individually infected host cells and is amenable to phenotype quantification. • Assay can be adapted to a broad array of pathogens and diverse host cell types. • Assay can identify virulence factors mediating a phenotype and protein domains that mediate a phenotype.

Effect of curcumin, betadine and chlorhexidine in gingival wound healing.

The effect of chlorhexidine (CHX) digluconate, Betadine (BET), curcumin (CUR) on gingival wound healing is of interest to dental practitioners. Hence, we studied the average fibroblast viability % for each of the concentrations of CUR, BET and CHX over various time durations. It was found that mean percentage of viability of fibroblasts is high in CUR and low in CHX at all time periods while the mean percentage of viability of fibroblasts in BET 1% was greater than CHX but lower than CUR at all time periods. Thus, curcumin at a concentration of 0.003% demonstrates the least cytotoxicity for fibroblasts. Hence, it is the most effective bacterial suppression, and the best wound healing.

Evaluating Fluoxetine's Growth-Inhibitory Impact on Clinical Isolates of Enteric Bacteria: Harnessing Repurposing Potential

The over-the-counter use and imprudent utilization of antibiotics in recent times have led to the emergence of microbial resistance. This has given rise to an alarming situation, prompting researchers to explore novel strategies for managing infections induced by antibiotic-resistant species. However, the process of drug discovery is time-consuming and expensive, which makes it a challenging endeavor. In recent years, drug repurposing has gained significant attention as an alternative strategy. Notably, several antidepressants have piqued interest as potential candidates for repositioning as antibiotics. Thus, the present study was aimed at investigating the anti-bacterial potential of different classes of antidepressants i.e., fluoxetine, venlafaxine, and phenelzine in clinical isolates of Escherichia coli, Enterobacter aerogenes, Enterococcus faecalis, Klebsiella pneumonia, Pseudomonas aeruginosa, Proteus mirabilis, Salmonella typhi, Shigella dysenteriae, and Staphylococcus aureus. The strains were cultivated on Mueller Hinton agar, with the aforementioned antidepressants or conventional antibiotics. Following a 24-hour incubation period, the extent of growth inhibition was assessed by measuring the zone of inhibition, serving as an indicator of their inhibitory potential. The findings showed that fluoxetine arrested the growth of almost all isolates with maximal effect against Pseudomonas aeruginosa. The impact of venlafaxine was exclusively observed in Enterobacter aerogenes, with phenelzine demonstrating complete ineffectiveness in bacterial growth suppression. In conclusion, the current study elucidates the efficacy of fluoxetine in clinical isolates, thereby positioning it as a promising contender for the advancement of novel antimicrobial agents. Additionally, our data raises questions regarding the proposed mechanisms of antibacterial action for selective serotonin reuptake inhibitors (SSRIs) and challenges the notion of dysbiosis as a potential mode of action for antidepressants.