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Microbiology Spectrum Feb 2022Antibiotic resistance has caused a serious threat to public health and human safety. Recently, the emergence of novel resistance gene (X4) and its variants threatens the...
Antibiotic resistance has caused a serious threat to public health and human safety. Recently, the emergence of novel resistance gene (X4) and its variants threatens the clinical utility of tigecycline, one of the last-line antibiotics for multidrug-resistant (MDR) bacterial infections. It is highly promising to develop effective antibiotic adjuvants to restore the clinical efficacy of existing drugs and extend their life spans. Metal compounds, such as silver, have been widely used as potential antimicrobial agents for decades. However, the potentiating effect of metallo-agents on the existing antibiotics is not fully understood. Here, we found that five bismuth drugs, especially bismuth nitrate [Bi(NO)], commonly used in clinical treatment of stomach-associated diseases, effectively boost the antibacterial activity of tigecycline against (X)-positive bacteria by inhibiting the enzymatic activity of Tet(X) protein. Furthermore, the combination of Bi(NO) and tigecycline prevents the development of higher-level resistance in Tet(X)-expressing Gram-negative bacteria. Using molecular docking and dynamics simulation assays, we revealed that Bi(NO) can competitively bind to the active center of Tet(X4) protein, while the bismuth atom targets the Tet(X4) protein in a noncompetitive manner and changes the structure of the primary binding pocket. These two mechanisms of action both antagonize the enzymatic activity of Tet(X4) resistance protein on tigecycline. Collectively, these findings indicate the high potential of bismuth drugs as novel Tet(X) inhibitors to treat (X4)-positive bacteria-associated infections in combination with tigecycline. Recently, high-level tigecycline resistance mediated by (X4) and its variants represents a serious challenge for global public health. Antibiotic adjuvant strategy that enhances the activity of the existing antibiotics by using nonantibiotic drugs offers a distinct approach to combat the antibiotic resistance crisis. In this study, we found that bismuth drugs involve bismuth nitrate, a compound previously approved for treatment of stomach-associated diseases, remarkably potentiates tigecycline activity against (X)-positive bacteria. Mechanistic studies showed that bismuth drugs effectively suppress the enzymatic activity of Tet(X) resistance protein. Specifically, bismuth nitrate targets the active center of Tet(X4) protein, while bismuth binds to the resistance protein in a noncompetitive manner. Our data open up a new horizon for the treatment of infections caused by (X)-bearing superbugs.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Bismuth; Drug Resistance, Multiple, Bacterial; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Microbial Sensitivity Tests; Molecular Docking Simulation; Tigecycline
PubMed: 35138168
DOI: 10.1128/spectrum.01578-21 -
ACS Applied Bio Materials May 2024Antimicrobial coatings provide protection against microbes colonization on surfaces. This can prevent the stabilization and proliferation of microorganisms. The...
Antimicrobial coatings provide protection against microbes colonization on surfaces. This can prevent the stabilization and proliferation of microorganisms. The ever-increasing levels of microbial resistance to antimicrobials are urging the development of alternative types of compounds that are potent across broad spectra of microorganisms and target different pathways. This will help to slow down the development of resistance and ideally halt it. The development of composite antimicrobial coatings (CACs) that can host and protect various antimicrobial agents and release them on demand is an approach to address this urgent need. In this work, new CACs based on microsized hybrids of calcium carbonate (CaCO) and silver nanoparticles (AgNPs) were designed using a drop-casting technique. Polyvinylpyrrolidone and mucin were used as additives. The CaCO/AgNPs hybrids contributed to endowing colloidal stability to the AgNPs and controlling their release, thereby ensuring the antibacterial activity of the coatings. Moreover, the additives PVP and mucin served as a matrix to (i) control the distribution of the hybrids, (ii) ensure mechanical integrity, and (iii) prevent the undesired release of AgNPs. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) techniques were used to characterize the 15 μm thick CAC. The antibacterial activity was determined against , methicillin-resistant (MRSA), and , three bacteria responsible for many healthcare infections. Antibacterial performance of the hybrids was demonstrated at concentrations between 15 and 30 μg/cm. Unloaded CaCO also presented bactericidal properties against MRSA. cytotoxicity tests demonstrated that the hybrids at bactericidal concentrations did not affect human dermal fibroblasts and human mesenchymal stem cell viability. In conclusion, this work presents a simple approach for the design and testing of advanced multicomponent and functional antimicrobial coatings that can protect active agents and release them on demand.
Topics: Calcium Carbonate; Silver; Anti-Bacterial Agents; Metal Nanoparticles; Humans; Materials Testing; Microbial Sensitivity Tests; Particle Size; Cell Survival; Coated Materials, Biocompatible; Escherichia coli; Surface Properties; Staphylococcus aureus
PubMed: 38721671
DOI: 10.1021/acsabm.3c01228 -
Chemosphere Jun 2022Cadmium is adsorbed on calcium carbonate via chemisorption. All calcium carbonate polymorphs generate otavite (cadmium carbonate), indicating that the crystallographic...
Cadmium is adsorbed on calcium carbonate via chemisorption. All calcium carbonate polymorphs generate otavite (cadmium carbonate), indicating that the crystallographic differences in calcium carbonate should affect the chemisorption equilibrium and kinetics. This study investigates the influences of the polymorph and specific surface area on cadmium adsorption. Here, we synthesise two polymorphs of porous calcium carbonate: calcite and vaterite with a wide range of specific surface areas. Then the equilibrium of cadmium adsorption is evaluated using adsorption isotherm models. Based on the Langmuir model with linear regression analysis, the maximum adsorptions of porous calcite and vaterite particles are 287.8 mg/g and 883.5 mg/g, respectively. The kinetics of cadmium chemisorption show clear differences between polymorphs. The calculated rate constant of the porous calcite particles using a pseudo-second-order reaction and Elovich models are two orders larger than that of porous vaterite particles. Although the adsorbed amount is superior for porous vaterite particles, porous calcite particles exhibit a faster reaction and relatively high adsorbed capacity for cadmium ions.
Topics: Adsorption; Cadmium; Calcium Carbonate; Kinetics; Porosity
PubMed: 35227751
DOI: 10.1016/j.chemosphere.2022.134057 -
MMWR. Recommendations and Reports :... Sep 2022THIS REPORT SUMMARIZES ALL RECOMMENDATIONS FROM CDC'S ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP) FOR THE USE OF LYOPHILIZED CVD 103-HGR VACCINE (CVD 103-HGR)...
THIS REPORT SUMMARIZES ALL RECOMMENDATIONS FROM CDC'S ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP) FOR THE USE OF LYOPHILIZED CVD 103-HGR VACCINE (CVD 103-HGR) (VAXCHORA, EMERGENT BIOSOLUTIONS, GAITHERSBURG, MD) IN THE UNITED STATES. THE LIVE ATTENUATED ORAL CHOLERA VACCINE IS DERIVED FROM: Vibrio cholerae O1 and is administered in a single dose. Cholera is a toxin-mediated bacterial gastrointestinal illness caused by toxigenic V. cholerae serogroup O1 or, uncommonly, O139. Up to 10% of infections manifest as severe cholera (i.e., cholera gravis), profuse watery diarrhea that can cause severe dehydration and death within hours. Fluid replacement therapy can reduce the fatality rate to <1%. Risk factors for cholera gravis include high dose exposure, blood group O, increased gastric pH (e.g., from antacid therapy), and partial gastrectomy. Cholera is rare in the United States, but cases occur among travelers to countries where cholera is endemic or epidemic and associated with unsafe water and inadequate sanitation. Travelers might be at increased risk for poor outcomes from cholera if they cannot readily access medical services or if they have a medical condition that would be worsened by dehydration, such as cardiovascular or kidney disease. This report describes previously published ACIP recommendations about use of CVD 103-HgR for adults aged 18-64 years and introduces a new recommendation for use in children and adolescents aged 2-17 years. ACIP recommends CVD 103-HgR, the only cholera vaccine licensed for use in the United States, for prevention of cholera among travelers aged 2-64 years to an area with active cholera transmission. Health care providers can use these guidelines to develop the pretravel consultation for persons traveling to areas with active cholera transmission.
Topics: Adolescent; Adult; Advisory Committees; Antacids; Blood Group Antigens; Child; Child, Preschool; Cholera; Cholera Vaccines; Dehydration; Humans; Middle Aged; United States; Vaccination; Vaccines, Attenuated; Vibrio cholerae O1; Water; Young Adult
PubMed: 36173766
DOI: 10.15585/mmwr.rr7102a1 -
Scientific Reports Jul 2021Herpes simplex virus is among the most prevalent sexually transmitted infections. Acyclovir is a potent, selective inhibitor of herpes viruses and it is indicated for...
Herpes simplex virus is among the most prevalent sexually transmitted infections. Acyclovir is a potent, selective inhibitor of herpes viruses and it is indicated for the treatment and management of recurrent cold sores on the lips and face, genital herpes, among other diseases. The problem of the oral bioavailability of acyclovir is limited because of the low permeability across the gastrointestinal membrane. The use of nanoparticles of pseudoboehmite as a drug delivery system in vitro assays is a promising approach to further the permeability of acyclovir release. Here we report the synthesis of high purity pseudoboehmite from aluminium nitrate and ammonium hydroxide containing nanoparticles, using the sol-gel method, as a drug delivery system to improve the systemic bioavailability of acyclovir. The presence of pseudoboehmite nanoparticles were verified by infrared spectroscopy, transmission electron microscopy, and X-ray diffraction techniques. In vivo tests were performed with Wistar rats to compare the release of acyclovir, with and without the addition of pseudoboehmite. The administration of acyclovir with the addition of pseudoboehmite increased the drug content by 4.6 times in the plasma of Wistar rats after 4 h administration. We determined that the toxicity of pseudoboehmite is low up to 10 mg/mL, in gel and the dried pseudoboehmite nanoparticles.
Topics: Acyclovir; Administration, Oral; Aluminum Hydroxide; Aluminum Oxide; Animals; Antiviral Agents; Biological Availability; Caco-2 Cells; Cell Survival; Drug Delivery Systems; Drug Liberation; Herpes Simplex; Humans; Models, Animal; Nanogels; Rats; Rats, Wistar; Simplexvirus
PubMed: 34326377
DOI: 10.1038/s41598-021-94325-y -
Molecular Biology and Evolution Jul 2022In Drosophila melanogaster, a key germline stem cell (GSC) differentiation factor, bag of marbles (bam) shows rapid bursts of amino acid fixations between sibling...
In Drosophila melanogaster, a key germline stem cell (GSC) differentiation factor, bag of marbles (bam) shows rapid bursts of amino acid fixations between sibling species D. melanogaster and Drosophila simulans, but not in the outgroup species Drosophila ananassae. Here, we test the null hypothesis that bam's differentiation function is conserved between D. melanogaster and four additional Drosophila species in the melanogaster species group spanning approximately 30 million years of divergence. Surprisingly, we demonstrate that bam is not necessary for oogenesis or spermatogenesis in Drosophila teissieri nor is bam necessary for spermatogenesis in D. ananassae. Remarkably bam function may change on a relatively short time scale. We further report tests of neutral sequence evolution at bam in additional species of Drosophila and find a positive, but not perfect, correlation between evidence for positive selection at bam and its essential role in GSC regulation and fertility for both males and females. Further characterization of bam function in more divergent lineages will be necessary to distinguish between bam's critical gametogenesis role being newly derived in D. melanogaster, D. simulans, Drosophila yakuba, and D. ananassae females or it being basal to the genus and subsequently lost in numerous lineages.
Topics: Animals; Calcium Carbonate; Drosophila; Drosophila Proteins; Drosophila melanogaster; Evolution, Molecular; Female; Male
PubMed: 35714266
DOI: 10.1093/molbev/msac137 -
Scientific Reports Jun 2022The preservation of soft tissue in the fossil record is mostly due to the replacement of organic structures by minerals (e.g. calcite, aragonite or apatite) called...
The preservation of soft tissue in the fossil record is mostly due to the replacement of organic structures by minerals (e.g. calcite, aragonite or apatite) called pseudomorphs. In rare cases soft tissues were preserved by pyrite. We assume that adipocere, as the shaping component, might be a preliminary stage in the pyritisation of soft tissues under anaerobic conditions. Using high-performance liquid chromatography coupled to ultraviolet and mass spectrometric detection (HPLC-UV/MS) and confocal Raman spectroscopy (CRS) we were able to demonstrate the transformation of the hepatopancreas (digestive gland) of the crayfish Cambarellus diminutus [Hobbs 1945] into adipocere within only 9 days, just inside a biofilm. Microorganisms (bacteria and fungi) which were responsible for the biofilm (Sphaerotilus [Kutzig 1833] and Pluteus [Fries 1857]) and maybe the adipocere formation (Clostridium [Prazmowski 1880]) were detected by 16S rRNA gene amplicon sequencing. Furthermore, micro-computed tomography (µ-CT) analyses revealed a precipitation of calcite and further showed that in animals with biofilm formation calcite precipitates in finer grained crystals than in individuals without biofilm formation, and that the precipitates were denser and replicated the structures of the cuticles better than the coarse precipitates.
Topics: Animals; Biofilms; Calcium Carbonate; Postmortem Changes; RNA, Ribosomal, 16S; Tissue Preservation; X-Ray Microtomography
PubMed: 35710834
DOI: 10.1038/s41598-022-14119-8 -
International Journal of Molecular... Jul 2022In this study, a photocatalytic antibacterial composite of polydopamine-reduced graphene oxide (PDA-rGO)/BiVO is prepared by a hydrothermal self-polymerization reduction...
In this study, a photocatalytic antibacterial composite of polydopamine-reduced graphene oxide (PDA-rGO)/BiVO is prepared by a hydrothermal self-polymerization reduction method. Its morphology and physicochemical properties are characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FT-IR), and X-ray diffraction (XRD). The results indicate that BiVO particles are evenly distributed on the rGO surface. () MG1655 is selected as the model bacteria, and its antibacterial performance is tested by flat colony counting and the MTT method under light irradiation. PDA-rGO/BiVO inhibits the growth of under both light and dark conditions, and light significantly enhances the bacteriostasis of PDA-rGO/BiVO. A combination of BiVO with PDA-rGO is confirmed by the above characterization methods as improving the photothermal performance under visible light irradiation. The composite possesses enhanced photocatalytic antibacterial activity. Additionally, the photocatalytic antibacterial mechanism is investigated via the morphology changes in the SEM images of MG1655 bacteria, 2',7'-dichlorofluorescein diacetate (DCFH-DA), the fluorescence detection of the reactive oxygen species (ROS), and gene expression. These results show that PDA-rGO/BiVO can produce more ROS and lead to bacterial death. Subsequently, the q-PCR results show that the transmembrane transport of bacteria is blocked and the respiratory chain is inhibited. This study may provide an important strategy for expanding the application of BiVO in biomedicine and studying the photocatalytic antibacterial mechanism.
Topics: Anti-Bacterial Agents; Bismuth; Catalysis; Escherichia coli; Graphite; Indoles; Light; Polymers; Reactive Oxygen Species; Spectroscopy, Fourier Transform Infrared; Vanadates
PubMed: 35887058
DOI: 10.3390/ijms23147712 -
International Journal of Molecular... Dec 2022Bismuth-based nanostructures (BBNs) have attracted extensive research attention due to their tremendous development in the fields of photocatalysis and... (Review)
Review
Bismuth-based nanostructures (BBNs) have attracted extensive research attention due to their tremendous development in the fields of photocatalysis and electro-catalysis. BBNs are considered potential photocatalysts because of their easily tuned electronic properties by changing their chemical composition, surface morphology, crystal structure, and band energies. However, their photocatalytic performance is not satisfactory yet, which limits their use in practical applications. To date, the charge carrier behavior of surface-engineered bismuth-based nanostructured photocatalysts has been under study to harness abundant solar energy for pollutant degradation and water splitting. Therefore, in this review, photocatalytic concepts and surface engineering for improving charge transport and the separation of available photocatalysts are first introduced. Afterward, the different strategies mainly implemented for the improvement of the photocatalytic activity are considered, including different synthetic approaches, the engineering of nanostructures, the influence of phase structure, and the active species produced from heterojunctions. Photocatalytic enhancement via the surface plasmon resonance effect is also examined and the photocatalytic performance of the bismuth-based photocatalytic mechanism is elucidated and discussed in detail, considering the different semiconductor junctions. Based on recent reports, current challenges and future directions for designing and developing bismuth-based nanostructured photocatalysts for enhanced photoactivity and stability are summarized.
Topics: Bismuth; Photochemical Processes; Semiconductors; Nanostructures; Solar Energy; Catalysis
PubMed: 36614112
DOI: 10.3390/ijms24010663 -
Molecules (Basel, Switzerland) Aug 2023Bismuth-based drugs have been used primarily to treat ulcers caused by and other gastrointestinal ailments. Combined with antibiotics, these drugs also possess... (Review)
Review
Bismuth-based drugs have been used primarily to treat ulcers caused by and other gastrointestinal ailments. Combined with antibiotics, these drugs also possess synergistic activity, making them ideal for multiple therapy regimens and overcoming bacterial resistance. Compounds based on bismuth have a low cost, are safe for human use, and some of them are also effective against tumoral cells, leishmaniasis, fungi, and viruses. However, these compounds have limited bioavailability in physiological environments. As a result, there is a growing interest in developing new bismuth compounds and approaches to overcome this challenge. Considering the beneficial properties of bismuth and the importance of discovering new drugs, this review focused on the last decade's updates involving bismuth compounds, especially those with potent activity and low toxicity, desirable characteristics for developing new drugs. In addition, bismuth-based compounds with dual activity were also highlighted, as well as their modes of action and structure-activity relationship, among other relevant discoveries. In this way, we hope this review provides a fertile ground for rationalizing new bismuth-based drugs.
Topics: Humans; Bismuth; Anti-Bacterial Agents; Helicobacter pylori; Helicobacter Infections; Drug Therapy, Combination
PubMed: 37570891
DOI: 10.3390/molecules28155921