Pyrogallol loaded chitosan-based polymeric hydrogel for controlling Acinetobacter baumannii wound infections: Synthesis, characterization, and topical application.

Antibacterial hydrogels have emerged as a promising approach for wound healing, owing to their ability to integrate antibacterial agents into the hydrogel matrix. Benefiting from its remarkable antibacterial and wound-healing attributes, pyrogallol has been introduced into chitosan-gelatin for the inaugural development of an innovative antibacterial polymeric hydrogel tailored for applications in wound healing. Hence, we observed the effectiveness of pyrogallol in inhibiting the growth of A. baumannii, disrupting mature biofilms, and showcasing robust antioxidant activity both in vitro and in vivo. In addition, pyrogallol promoted the migration of human epidermal keratinocytes and exhibited wound healing activity in zebrafish. These findings suggest that pyrogallol holds promise as a therapeutic agent for wound healing. Interestingly, the pyrogallol-loaded chitosan-gelatin (Pyro-CG) hydrogel exhibited enhanced mechanical strength, stability, controlled drug release, biodegradability, antibacterial activity, and biocompatibility. In vivo results established that Pyro-CG hydrogel promotes wound closure and re-epithelialization in A. baumannii-induced wounds in molly fish. Therefore, the prepared Pyro-CG polymeric hydrogel stands poised as a potent and promising agent for wound healing with antibacterial properties. This holds considerable promise for the development of effective therapeutic interventions to address the increasing menace of A. baumannii-induced wound infections.

Hesperidin methyl chalcone, a citrus flavonoid, inhibits Aeromonas hydrophila infection mediated by quorum sensing.

Plant-derived phytocompounds are effective in treating a variety of ailments and disorders, the most common of which are bacterial infections in humans, which are a major public health concern. Flavonoids, one of the groups of phytocompounds, are known to have significant antimicrobial and anti-infective properties. Hence, the current study investigates the efficacy of the citrus flavonoid hesperidin methylchalcone (HMC) in addressing this major issue. The results of this study indicate that the anti-quorum sensing (anti-QS) action against Aeromonas hydrophila infections is exhibited with a decrease in biofilm development and virulence factors production through in vitro and in silico analyses. In addition, the qPCR findings indicate that HMC has antivirulence action on A. hydrophila by reducing the expression of QS-related virulence genes, including ahyR, ahyB, ahh1, aerA, and lip. Interestingly, HMC significantly rescued the A. hydrophila-infected zebrafish by reducing the internal colonization, demonstrating the in vivo anti-infective potential of HMC against A. hydrophila infection. Based on these results, this study recommends that HMC could be employed as a possible therapeutic agent to treat A. hydrophila-related infections in humans.

Tocopherol-assisted magnetic Ag-Fe3O4-TiO2 nanocomposite for photocatalytic bacterial-inactivation with elucidation of mechanism and its hazardous level assessment with zebrafish model.

In recent years, many endeavours have been prompted with photocatalytic nanomaterials by the need to eradicate pathogenic microorganisms from water bodies. Herein, a tocopherol-assisted Ag-Fe3O4-TiO2 nanocomposite (TAFTN) was synthesized for photocatalytic bacterial inactivation. The prepared TAFTN became active under sunlight due to its narrowed bandgap, inactivating the bacterial contaminants via photo-induced ROS stress. The ROS radicals destroy bacteria by creating oxidative stress, which damages the cell membrane and cellular components such as nucleic acids and proteins. For the first time, the nano-LC-MS/MS-based quantitative proteomics reveals that the disrupted proteins are involved in a variety of cellular functions; the most of these are involved in the metabolic pathway, eventually leading to bacterial death during TAFTN-photocatalysis under sunlight. Furthermore, the toxicity analysis confirmed that the inactivated bacteria seemed to have no detrimental impact on zebrafish model, showing that the disinfected water via TAFTN-photocatalysis is enormously safe. Furthermore, the TAFTN-photocatalysis successfully killed the bacterial cells in natural seawater, indicating the consistent photocatalytic efficacy when recycled repeatedly. The results of this work demonstrate that the produced nanocomposite might be a powerful recyclable and sunlight-active photocatalyst for environmental water treatment.

Pyrogallol downregulates the expression of virulence-associated proteins in Acinetobacter baumannii and showing anti-infection activity by improving non-specific immune response in zebrafish model.

Acinetobacter baumannii, a virulent uropathogen with widespread antibiotic resistance, has arisen as a critical scientific challenge, necessitating the development of innovative therapeutic agents. This is the first study reveal the proteomic changes in A. baumannii upon pyrogallol treatment for understanding the mechanisms using nano-LC-MS/MS-based quantitative proteomics and qPCR analysis. The obtained results found that pyrogallol treatment dramatically downregulated the expression level of several key proteins such as GroEL, DnaK, ClpB, SodB, KatE, Bap, CsuA/B, PgaA, PgaC, BfmR, OmpA, and SecA in A. baumannii, which are involved in chaperone-mediated oxidative stress responses, antioxidant defence system, biofilm formation, virulence enzyme production, bacterial adhesion, capsule formation, and antibiotic resistance. Accordingly, the pyrogallol dramatically enhanced the lifespan of A. baumannii-infected zebrafish by inhibiting bacterial colonization, demonstrating the anti-infective potential of pyrogallol against A. baumannii. Further, the histopathological results also demonstrated the disease protection efficacy of pyrogallol against the pathognomonic sign of A. baumannii infection. In addition, the pyrogallol treatment effectively improved the immune parameters such as serum myeloperoxidase activity, leukocyte respiratory burst activity, and serum lysozyme activity in zebrafish against A. baumannii infection. Based on the results, the present study strongly proposes pyrogallol as a promising therapeutic agent for treating A. baumannii infection.

Repurposing of Doxycycline to Hinder the Viral Replication of SARS-CoV-2: From in silico to in vitro Validation.

Since the rapid spread of coronavirus disease (COVID-19) became a global pandemic, healthcare ministries around the world have recommended specific control methods such as quarantining infected peoples, identifying infections, wearing mask, and practicing hand hygiene. Since no effective treatment for COVID-19 has yet been discovered, a variety of drugs approved by Food and Drug Administration (FDA) have been suggested for repurposing strategy. In the current study, we predicted that doxycycline could interact with the nucleotide triphosphate (NTP) entry channel, and is therefore expected to hinder the viral replication of SARS-CoV-2 RNA-dependent RNA-polymerase (RdRp) through docking analysis. Further, the molecular dynamics results revealed that the RdRp-Doxycycline complex was structurally relatively stable during the dynamic period (100 ns), and its complex maintained close contact with their active catalytic domains of SARS-CoV-2 RdRp. The molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) calculation of binding free energy also showed that the doxycycline has worthy affinities with SARS-CoV-2 RdRp. As expected, doxycycline effectively inhibited the viral replication of IHU strains of SARS-CoV-2 (IHUMI-3 and IHUMI-6), identified from the hospitalized patients in IHU Méditerranée Infection (IHUMI), Marseille, France. Moreover, doxycycline inhibited the viral load in vitro at both on-entry and after viral entry of IHU variants of SARS-CoV-2. The results suggest that doxycycline exhibits strains-dependant antiviral activity against COVID-19. As a result, the current study concludes that doxycycline may be more effective in combination with other drugs for better COVID-19 treatment efficacy.

Sunlight-active phytol-ZnO@TiO2 nanocomposite for photocatalytic water remediation and bacterial-fouling control in aquaculture: A comprehensive study on safety-level assessment.

With a growing consciousness of the importance of nature stewardship, researchers are focusing their efforts on utilizing renewable energy, particularly solar energy, to address environmental concerns. In this context, photocatalysis has long been viewed as one of the most promising cleaning methods. Hence, we have prepared a sunlight-active phytol-assisted ZnO-TiO2 nanocomposite (PZTN) for photocatalytic bacterial deactivation and dye degradation process. The PZTN-photocatalysis effectively deactivated the bacterial pathogens as well as malachite green dye within 240 min under direct-sunlight. Moreover, this will be the first complete study on safety level assessment of photocatalytically-remediated water through toxicity studies. The obtained results evidenced that photocatalytically-deactivated bacteria and MG-dye showed to have no toxic effects, signifying that the PZTN-photocatalyzed water seems to be extremely safe for the environment. As a result of this research, we suggest that the PZTN could be a promising sunlight-active photocatalyst for environmental water treatment. On the other hand, biofouling is a ubiquitous phenomenon in the marine environment. Bacteria are the first organisms to foul surfaces and produce biofilms on man-made submerged materials. Interestingly, PZTN-coated PVC plastic-films effectively disallowed biofilms on their surface. This part of this research suggests that PZTN coated PVC-plastics are the best alternative for biofouling management.

Tocopherol and phytol possess anti-quorum sensing mediated anti-infective behavior against Vibrio campbellii in aquaculture: An in vitro and in vivo study.

Phytocompounds have long been well recognized in medicine and pharmacy. The natural compounds are frequently utilized as the fundamental resource in the development of novel therapeutic agents to treat bacterial infections. The rapid emergence of bacterial infections, particularly caused by Vibrio species, is seen as a serious concern for the development of aquaculture industries, resulting in substantial economic losses throughout the world. Notably, the presence of Vibrio campbellii in aquatic environments will be extremely problematic, leading to significant mortality in aquatic organisms. As a result, novel therapeutic agents are desperately needed to treat such diseases. This is the first research to demonstrate that plant-derived active compounds, tocopherol and phytol, are effective against V. campbellii infection in tomato clownfish. The findings showed that tocopherol and phytol significantly decreased the production of biofilm and virulence factors such as hemolysin, protease, lipase, hydrophobic index, and swimming motility in V. campbellii, without influencing the bacterial growth. In vivo experiments with tomato clownfish also proved that these phytocompound treatments significantly increased the survival rates of infected fishes by hindering the intestinal colonization of V. campbellii in tomato clownfish. Further, the disease protection efficacy against the pathognomonic sign of V. campbellii-infection was verified by histopathological investigation of the gills, gut, and kidney. Altogether, the results suggest that tocopherol and phytol could be promising therapeutic agents for the treatment of V. campbellii infections in aquaculture.

Gene expressing analysis indicates the role of Pyrogallol as a novel antibiofilm and antivirulence agent against Acinetobacter baumannii.

Acinetobacter baumannii has emerged worldwide as a leading cause of hospital-acquired infections. Although A. baumannii was initially regarded to as a low-grade pathogen, evidence has been accumulated suggesting that A. baumannii infections are associated with increased mortality in critically ill patients. Here, we describe the efficacy of pyrogallol, a polyphenolic organic compound found in the galls and barks of various trees, which shows anti-biofilm and anti-virulence potential against A. baumannii. Pyrogallol shows concentration-based biofilm inhibition, as evidenced through light and confocal laser scanning microscopic analysis. The other virulence factors are protease, swarming motility, and extracellular polymeric substances that are also inhibited by pyrogallol. Through real-time PCR, it was found that pyrogallol downregulates expression of the biofilm and virulence-related ompA, bap, csuA/B, katE, pgaA, and pgaC genes. Furthermore, pyrogallol moderately inhibited the mature biofilms of A. baumannii in a concentration-dependent manner (5, 10, and 20 µg/ml). The present study reports that the anti-biofilm and anti-virulence potential of pyrogallol disrupts the biofilm formation, adherence of cells, and cell-to-cell signaling mechanism of A. baumannii. Thus, pyrogallol is a promising therapeutic agent for A. baumannii-related infections.

Inhibitory Effect of Morin Against Candida albicans Pathogenicity and Virulence Factor Production: An in vitro and in vivo Approaches.

Candida albicans is considered an exclusive etiologic agent of candidiasis, a very common fungal infection in human. The expression of virulence factors contributes highly to the pathogenicity of C. albicans. These factors include biofilm formation, yeast-to-hyphal transition, adhesins, aspartyl proteases, and phospholipases secretion. Moreover, resistance development is a critical issue for the therapeutic failure of antifungal agents against systemic candidiasis. To circumvent resistance development, the present study investigated the virulence targeted therapeutic activity of the phyto-bioactive compound morin against C. albicans. Morin is a natural compound commonly found in medicinal plants and widely used in the pharmaceutical and cosmetic products/industries. The present study explicated the significant inhibitory potential of morin against biofilm formation and other virulence factors' production, such as yeast-hyphal formation, phospholipase, and exopolymeric substances, in C. albicans. Further, qPCR analysis confirmed the downregulation of biofilm and virlence-related genes in C. albicans upon morin treatment, which is in correspondence with the in vitro bioassays. Further, the docking analysis revealed that morin shows strong affinity with Hwp-1 protein, which regulates the expression of biofilm and hyphal formation in C. albicans and, thereby, abolishes fungal pathogenicity. Moreover, the anti-infective potential of morin against C. albicans-associated systemic candidiasis is confirmed through an in vivo approach using biomedical model organism zebrafish (Danio rerio). The outcomes of the in vivo study demonstrate that the morin treatment effectively rescues animals from C. albicans infections and extends their survival rate by inhibiting the internal colonization of C. albicans. Histopathology analysis revealed extensive candidiasis-related pathognomonic changes in the gills, intestine, and kidney of animals infected with C. albicans, while no extensive abnormalities were observed in morin-treated animals. The results evidenced that morin has the ability to protect against the pathognomonic effect and histopathological lesions caused by C. albicans infection in zebrafish. Thus, the present study suggests that the utilization of morin could act as a potent therapeutic medication for C. albicans instigated candidiasis.

Proteomic analysis deciphers the multi-targeting antivirulence activity of tannic acid in modulating the expression of MrpA, FlhD, UreR, HpmA and Nrp system in Proteus mirabilis.

In the present study, the multi-targeting antivirulence activity of tannic acid (TA) was explored against Proteus mirabilis through MS-based proteomic approach. The in vitro biofilm biomass quantification assay and microscopic analysis demonstrated the antibiofilm activity of TA against P. mirabilis in which, minimum biofilm inhibitory concentration (MBIC) of TA was found to be 200 µg/mL concentration. Moreover, the nanoscale liquid chromatography coupled to tandem mass spectrometry (nano LC-MS/MS) analysis revealed that TA (at MBIC) differentially regulated the proteins involved in fimbrial adhesion, flagellar motility, iron acquisition, Fe-S cluster assembly, heat shock response, virulence enzymes, and toxin secretion. Further, the transcriptomic analysis validated the outcomes of proteomic analysis in which, the expression level of virulence genes responsible for MR/P fimbrial adhesion (mrpA), flagellar transcriptional activation (flhD), biosynthesis of urease (ureR), hemolysin (hpmA), non-ribosomal peptide siderophore system (Nrp), oxidative stress responsible enzymes and fitness factors proteins were down-regulated in TA exposed P. mirabilis. These observations were also in correspondence with the in vitro bioassays. Thus, this study reports the feasibility of TA to act as a promising therapeutic agent against multifactorial P. mirabilis infections.

Virulence targeted inhibitory effect of linalool against the exclusive uropathogen Proteus mirabilis.

Proteus mirabilis is one of the leading causes of catheter-associated UTIs (CAUTI) in individuals with prolonged urinary catheterization. Since, biofilm assisted antibiotic resistance is reported to complicate the treatment strategies of P. mirabilis infections, the present study was aimed to attenuate biofilm and virulence factor production in P. mirabilis. Linalool is a naturally occurring monoterpene alcohol found in a wide range of flowers and spice plants and has many biological applications. In this study, linalool exhibited concentration dependent anti-biofilm activity against crystalline biofilm of P. mirabilis through reduced production of the virulence enzyme urease that raises the urinary pH and drives the formation of crystals (struvite) in the biofilm. The results of q-PCR analysis unveiled the down regulation of biofilm/virulence associated genes upon linalool treatment, which was in correspondence with the in vitro bioassays. Thus, this study reports the feasibility of linalool acting as a promising anti-biofilm agent against P. mirabilis mediated CAUTI.

Explication of the Potential of 2-Hydroxy-4-Methoxybenzaldehyde in Hampering Uropathogenic Proteus mirabilis Crystalline Biofilm and Virulence.

Proteus mirabilis is an important etiological agent of catheter-associated urinary tract infections (CAUTIs) owing to its efficient crystalline biofilm formation and virulence enzyme production. Hence, the present study explicated the antibiofilm and antivirulence efficacies of 2-hydroxy-4-methoxybenzaldehyde (HMB) against P. mirabilis in a non-bactericidal manner. HMB showed concentration-dependent biofilm inhibition, which was also evinced in light, confocal, and scanning electron microscopic (SEM) analyses. The other virulence factors such as urease, hemolysin, siderophores, and extracellular polymeric substances production as well as swimming and swarming motility were also inhibited by HMB treatment. Further, HMB treatment effectively reduced the struvite/apatite production as well as crystalline biofilm formation by P. mirabilis. Furthermore, the results of gene expression analysis unveiled the ability of HMB to impair the expression level of virulence genes such as flhB, flhD, rsbA, speA, ureR, hpmA, and hpmB, which was found to be in correlation with the results of in vitro bioassays. Additionally, the cytotoxicity analysis divulged the innocuous characteristic of HMB against human embryonic kidney cells. Thus, the present study reports the potency of HMB to act as a promising therapeutic remedy for P. mirabilis-instigated CAUTIs.