Gram-negative Bacterial Strains Research Articles

Evaluation of the in Vitro Antibacterial Activity of Natural kinds of Multi-floral Honey Against Selected Gram-Positive and Gram-Negative Bacterial Strains

Evaluation of the in Vitro Antibacterial Activity of Natural kinds of Multi-floral Honey Against Selected Gram-Positive and Gram-Negative Bacterial Strains

Repurposed Anti-Multiple Sclerosis Drug Fty720 Targets Carbapenem-Resistant Acinetobacter baumannii via Multiple Pathways.

Bacterial antimicrobial resistance (AMR), particularly multidrug resistance (MDR) in gram-negative bacterial strains, has emerged as a formidable challenge of substantial consequence, necessitating an urgent pursuit of a sustainable and efficacious strategic response. Repurposing nonantibiotic drugs as potential antibiotics or antibiotic adjuvants is a valuable approach to targeting MDR bacteria. A total of 1,750 FDA-approved drugs (APExBIO, USA) were screened to test their antimicrobial activities against MDR bacteria using the broth microdilution method according to the standard of the Clinical and Laboratory Standards Institute (CLSI). Microscale thermophoresis (MST) analysis was performed to detect the Fty720-LPS interactions. Fty720-indcued lipid changes were measured by untargeted lipidomic analysis. Isothermal titration calorimetry (ITC) analysis was used to determine the Fty720-lipid binding affinities. DNA degradation was assessed via agarose gel electrophoresis with ethidium bromide (EB) staining and visualized using a gel imaging system. Galleria mellonella larvae infection model and Mouse peritonitis infection models were used to evaluated the antibacterial ability of Fty720 in vivo. In this study, we identified Fty720, a pharmaceutical agent for treating multiple sclerosis, as a potent inhibitor of carbapenem-resistant Acinetobacter baumannii (CRAB). We demonstrated that Fty720 exerts antibacterial effects through multiple strategies, including disruption of the structural integrity of the membranes by interacting with LPS and glycerophospholipids, as well as degradation of bacterial DNA. Furthermore, through judicious structural modification, the pivotal role of the positively charged moiety (NH2) in Fty720's antibacterial activity was substantiated. Intriguingly, the translation of Fty720's antibacterial efficacy was demonstrated in vivo, substantiating its pronounced influence on elevating survival rates among models afflicted with MDR gram-negative bacterial infections. Fty720 targets CRAB via multiple pathways, including disruption of outer and inner membrane integrity and DNA degradation. This investigation unveils the multifaceted antibacterial mechanisms of Fty720 while concurrently delineating a prospective therapeutic avenue to counteract MDR gram-negative bacterial strains.

Effect of silver ion and silicate group on the antibacterial and antifungal properties of nanosized hydroxyapatite

Hydroxyapatite is one of the most widely used materials in biomedical applications in reparative and regenerative medicine. Doping of nanosized hydroxyapatite improves its bioactive properties, and thus, the synthesis of different types of nanohydroxyapatite with antimicrobial activity is a perspective route of modern materials science. In this study, undoped hydroxyapatite (HAp), hydroxyapatite doped with silver (HAp with 0.1, 0.5 and 1 mol% Ag+ ions), and silicate-substituted hydroxyapatite doped with silver (Si-HAp with 0.1, 0.5 and 1 mol% Ag+ ions) nanoparticles (NPs) were synthesized by microwave-assisted hydrothermal technique and sintered at 450 °C. The structural properties and composition of obtained hydroxyapatite NPs were investigated using X-ray powder diffraction (XRPD), Fourier-transformed infrared spectroscopy (FT-IR), and Energy-dispersive X-ray spectroscopy (EDS). The morphology of synthesized nanosized powders was detected using the high-resolution transmission electron microscopy (HRTEM) technique. The results of XRPD for all synthesized nanosized powders confirmed the presence of hydroxyapatite crystal structure. The FT-IR spectra confirmed the presence of functional groups characteristic of the hydroxyapatite structure. The EDS analysis of obtained materials has shown the presence of Ca, P, O, Si, and Ag elements. Significant differences in size and morphology of the obtained particles were found using HRTEM. The particles have an elongated, rod-like shape with subtle differences. Moreover, HAp doped with 1 mol% Ag+ ions and Si-HAp doped with 1 mol% Ag+ ions nanosized powders showed antibacterial activity in comparison to pure hydroxyapatite both against gram-positive and gram-negative bacterial strains (Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis). These two types of hydroxyapatite NPs also demonstrated antifungal activity against reference strains of Candida albicans, Candida kruzei, and Candida tropicalis, with stronger activity observed for Si-HAp doped with silver.

Characterization of Serratia marcescens (OK482790)’ prodigiosin along with in vitro and in silico validation for its medicinal bioactivities

BackgroundMicrobial prodigiosin pigment has been proposed as a promising biomolecule having an antibacterial, immunosuppressive, antimalarial, antineoplastic, and anticancer activities. The good outcome originates from getting natural pigment, which has many medical applications.ResultsIn this investigation, prodigiosin (PG) was extracted, characterized by UV-visible spectroscopy, thin-layer chromatography, mass spectroscopy, Fourier-transform infrared spectroscopy, and tested in various medical applications as an antibacterial, antioxidant, antibiofilm, anticancer, and wound healing agent at different concentrations. Antibacterial activity of PG pigment was shown against both Gram-positive and Gram-negative bacterial strains. Enterococcus faecalis was the most severely impacted, with minimum inhibitory value of 3.9 µg/mL. The formed biofilm by Pseudomonas aeruginosa was suppressed by 58–2.50% at prodigiosin doses ranging from 1000 to 31.25 µg/mL, respectively. The half-maximal inhibitory concentration (IC50) of 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) free radical was 74.18 ± 23.77 µg/mL. At 100 µg/mL concentration, OK482790 prodigiosin had no harmful effect on normal skin cells and exhibited mild wound healing properties. Additionally, molecular docking simulations confirmed the prodigiosin’s interactions with target proteins, including epidermal growth factor receptor tyrosine kinase (EGFR-TK, PDB ID: 1M17), peptide deformylase from E. faecalis (PDB ID: 2OS1), acidic fibroblast growth factor (FGF-1, PDB ID: 3K1X), PA14_16140 protein from P. aeruginosa (PDB ID: 8Q8O), and human peroxiredoxin 5 (PDB ID: 1HD2) for explaining the anticancer, antibacterial, wound healing, antibiofilm, and antioxidant activities, respectively. Prodigiosin had favorable binding affinities and putative modes of action across various therapeutic domains.ConclusionThis study pioneers the use of prodigiosin as a natural alternative to synthetic medicine since it fights germs, heals wounds, is antioxidant, and reduces biofilm formation.Clinical trial numberNot applicable.

Bio-computational modeling, POM analysis and molecular dynamic simulation for novel synthetic quinolone and benzo[d][1,3]oxazine candidates as antimicrobial inhibitors

The current study offers a metal-free, direct, and successful synthesis technique for a new series of quinolinone and benzo[d][1,3]oxazine, along with an assessment of their biological activities. Heteroannulation of anthranilic acid with carbonyl-containing chemicals (aroyl pyruvate, ethyl acetoacetatete, maleic anhydride, and ethyl cyanoacetate) resulted in the desired quinolones and benzo[d][1,3]oxazines. This technique introduces a number of fundamental breakthroughs in organic synthesis, including metal-free catalysts, smart reaction conditions with column purification, and a wide functional scope. Furthermore, the structure of the newly synthesized chemical series was investigated and validated using spectroscopic techniques. The synthesized series were evaluated for antibacterial (against gram-positive and gram-negative bacterial strains) and antifungal activity. The quinolone and benzo[d][1,3]oxazine candidates had remarkable antibacterial action. Furthermore, molecular docking investigations corroborated the biological studies using the Molecular Operating Environment and Petro Osiris Molinspiration (POM) experiments, which confirmed the activity of compounds 8, 15, and 17. Our studies on the cytotoxic activity of various chemicals have demonstrated that these compounds exhibit minimal toxicity. Specifically, when comparing the cytotoxic effects on human lung fibroblast (WI38) cells to those of Doxorubicin, a well-known chemotherapy agent, compounds 8, 15, and 17 showed weak cytotoxic effects on the normal WI38 cells. This indicates that these compounds may possess some level of selectivity and reduced toxicity towards normal cells, suggesting potential for further exploration as antibacterial agents with a safer profile for normal cells.

Rhodamine-B degradation, chromium removal and bactericidal potential of Cu–ZnO@ZrO2 nanoneedles fabricated via green route

Nanoparticles are being used for diverse environmental as well as biomedical applications due to their versatile features. In current work, a facile green synthesis route was employed for the fabrication of Cu–ZnO@ZrO2 nano-needles (NNs) using Momordica charantia (MC) stem extract and ZrO2 was used as a precursor along with CuCl2 and ZnCl2. UV–Vis and FTIR analysis confirmed the formation of Cu–ZnO@ZrO2 NNs. XRD studies confirmed orthorhombic geometry and FE-SEM images confirmed needle like structure of the prepared Cu–ZnO@ZrO2. Catalytic potential of the synthesized NNs was evaluated in terms of its efficiency towards degradation of rhodamine-B (Rh–B) dye. Degradation was achieved up to 98 % in 14 min in the presence of NNs. Conditions were optimized for the maximum removal of the dye using ascorbic acid (AA) as a reducing agent. Synthesized NNs sample was tested against another toxic pollutant i.e. Cr (VI) that was removed up to 65 % from aqueous medium. Promising antibacterial activity of the NNs was recorded against gram-positive and gram-negative bacterial strains. The results of the current study revealed promising features of NNs suggesting its use for the removal of microorganisms, organic and metallic pollutants. Authors would strongly suggest the fabrication of nanocomposites of same composition for the treatment of toxic pollutants in aqueous medium.

Exploring the Efficacy of pH-Responsive Vancomycin/Ag/ZIF-8 Nanoparticles Modified with Hyaluronic Acid for Enhanced Antibacterial Therapy and Wound Healing.

This study introduces a novel type of metal-organic framework material, specifically zeolitic imidazolate framework-8 (ZIF-8), that is integrated with silver nanoparticles and further enhanced by incorporating vancomycin (Van) to create a composite named as Van/Ag/ZIF-8. This composite demonstrates a potent and smart antimicrobial effect due to its ability for releasing silver ions and Van in a controlled manner, especially in the microacidic conditions surrounding bacterial cells. Furthermore, we used hyaluronic acid to modify Van/Ag/ZIF-8, resulting in a composite denoted as Van/Ag/ZIF-8@HA. This composite exhibits a significant inhibition effect against the proliferation of both Gram-negative (Escherichia coli 100%) and Gram-positive (Staphylococcus aureus 99.9%) resistant bacterial strains while exerting no adverse effects on animal cellular growth. These findings underscore its favorable biocompatibility profile. The experimental results show a combined antibacterial action against prevalent bacterial infections, which is supported by in vivo experiments using a skin wound model. This work confirms the composite's significant role in fighting pathogenic infections and aiding in healing skin wounds. The innovative strategy not only tackles the pressing issue of antibiotic-resistant bacterial infections but also marks a significant advancement in the areas of wound healing and medical research, offering a promising path for future investigations and therapeutic uses.

A potent moiety of (E)-5-(4-(5-chlorothiophene-2-carbonyl) piperazin-1-yl)-N'-(substituted methylene) benzofuran-2-carbohydrazide: Molecular docking, synthesis and antimicrobial evaluation

In this paper, we report new hybrid molecules of (E)-5-(4-(5-chlorothiophene-2-carbonyl) piperazin-1-yl)-N'-(substituted methylene) benzofuran-2-carbohydrazide (10a-10r) as an anti-microbial agent. The synthesized compounds have been characterized by FT-IR, Mass, 1H and 13C NMR spectroscopic techniques and were evaluated on gram-positive (S. aureus and S. pyogenes), gram-negative (E. coli and P. aeruginosa) bacterial strain and fungal (C. albicans and A. Niger) strains by the broth dilution method. The compounds exhibited significant antibacterial and antifungal activities, out of which compounds 10b and 10o, having MIC 62.5 μg/mL, showed the best activity against gram-positive bacterial strain S. aureus. Furthermore, compounds 10e, 10j, and 10m, having MIC 62.5 μg/mL, showed the best activity against the gram-negative bacterial strain E. coli. In contrast, compounds 10g and 10n, having MIC 62.5 μg/mL, showed the best activity against gram-negative bacterial strain P. aeruginosa. Out of the series, compounds 10h and 10l have been found to possess better inhibitory activity with MIC 250 μg/mL, compared to standard drug Griseofulvin (MIC 500 μg/mL) against anti-fungal strain C. albicans. Additionally, the compounds were docked in DNA gyrase enzyme of gram-positive and gram-negative bacteria and also C. albicans fungal. Compounds 10h and 10l were docked with the CYP51 of C. albicans (PDB: 5V5Z), revealing that the benzyl ring of the carbohydrazide Schiff base formed a potent π-π stacking interaction with the Hem601 complex. Additionally, the carbonyl part of the amide functional group connecting the piperazine and thiophene rings was found to interact with His377 through a hydrogen bond, which is considered a significant interaction. The compounds are also checked for their drug-likeness property using Lipinski rule. On the basis of these findings, we can conclude that (E)-5-(4-(5-chlorothiophene-2-carbonyl) piperazin-1-yl)-N'-(substituted methylene) benzofuran-2-carbohydrazide is a potent antimicrobial agent against a variety of bacterial and fungal species.

Green Synthesis of Nanoparticle-Loaded Bacterial Cellulose Membranes with Antibacterial Properties

The current work proposes the development of composite membranes based on bacterial cellulose (BC) loaded with silver (Ag) and zinc oxide (ZnO) nanostructures by in situ impregnation. The research involves the production and purification of BC, followed by its loading with different types of phases with the help of different precipitating solutions, turmeric extract (green synthesis) and ammonia (classic route). Additionally, the combination of both antibacterial agents into a single BC matrix to valorise the benefits of each, proposing a novel BC-Ag-ZnO composite with distinct characteristics, was explored. Overall, the synthesis was marked by colour changes from the light beige of the BC membrane to dark brown, dark orange and dark green for BC-Ag, BC-ZnO and BC-Ag-ZnO samples, which is proof of successful composites formation. The results proved that the antibacterial phases are attached as nanoparticles or nanosheets on BC fibres, with Ag being in a crystalline state, while ZnO showed a rather amorphous structure. Regarding the antibacterial efficiency, the BC-ZnO composite obtained by employing two precipitating solutions turned out to be the best material against both tested Gram-negative and Gram-positive bacterial strains.

Isolation, characterization, and whole genome sequencing analysis of Aeromonas veronii from Channa argus in China.

Aeromonas veronii has emerged as a significant pathogen that impacts both fish and mammals. Recently, an infectious disease characterized by multiple ulcers on the body surface with a high mortality rate occurred in Channa argus cultured in Jiangsu Province, China. A Gram-negative bacterial strain (Aer12) was isolated from the body surface of the diseased fish and identified as A. veronii by the physiological, biochemical, and 16S rRNA gene analysis. Intra-peritoneal injection of Aer12 into the healthy C. argus resulted in the development of multiple ulcers on the body surface, and the histopathological results showed that muscle tissue rupture was the most severe symptom. Aer12 showed both protease and lipase activities with no β-hemolytic activity. Furthermore, Aer12 contained seven virulence genes (aer, act, alt, fla, ascV, aexT, and ela) and one antibiotic resistance gene (qnrS) identified by the PCR assay. The results of whole genome sequencing revealed that Aer12 had a circular chromosome that measured 4,719,428bp. It comprised 4301 predicted protein-coding sequences (CDS) in addition to 31 rRNA, 124 tRNA, and 49 sRNA genes. Furthermore, a total of 676 virulence genes and 216 antibiotic resistance genes have been predicted. Aer12 was susceptible to 21 antibiotics, including ampicillin and erythromycin. The results of Chinese herbs susceptibility assay showed that Aer12 was highly susceptible to Sanguisorba officinalis, Galla chinensis, and Schisandra chinensis. The results of this study will serve as a reference for future research on the pathogenic mechanism of A. veronii and the prevention and control of bacterial diseases in C. argus farming.

Molecular Analysis of Gram-Negative Bacterial Strains in Patients from Koya City

This study addresses the critical issue of Gram-negative bacteria (GNB) in patients from Koya City, acknowledging their significant resistance to antibiotics and the consequent threat to public health. A total of 14 samples were collected from diverse patient demographics and sources, including urine, wounds, vaginal swabs, seminal fluid, and throat swabs. The samples were subjected to analysis through a multifaceted approach involving culturing and molecular identification. Following the isolation of bacterial samples, the 16SrRNA gene was targeted using polymerase chain reaction (PCR). Subsequently, the obtained PCR products underwent Sanger sequencing, providing a detailed analysis of the nucleotide sequences. The resulting sequences were then compared against existing prokaryotic DNA sequences in the BLAST database to determine the identity of the isolated bacteria. Out of the 14 samples, 13 yielded sequences of good quality, while one exhibited a noise sequence. The sequences were further aligned, and 11 samples demonstrated a 100% identity with previously identified bacteria such as Escherichia coli (100 %), Klebsiella pneumoniae (100 %), and Shigella flexneri (100 %) Notably, two samples displayed a >99% identity with Escherichia coli (99.5%), highlighting the diversity within the bacterial strains. This study sheds light on the prevalence and identity of Gram-negative bacteria in Koya City patients. The findings underscore the necessity of molecular techniques, such as PCR and sequencing, in clinical diagnostics. The diverse bacterial strains identified highlight the complexity of bacterial infections, emphasizing the importance of targeted approaches in addressing antibiotic resistance.

Development of Cyclometalated Iridium(III) Complexes of 2-Phenylbenzimidazole and Bipyridine Ligands for Selective Elimination of Gram-Positive Bacteria.

Herein, we have reported a series of cationic aggregation-induced emission (AIE) active iridium(III) complexes (Ir1-Ir5) of the type [Ir(C^N)2(N^N)]Cl, wherein C^N is a cyclometalating 2-phenylbenzimidazole ligand with varying alkyl chain lengths and N^N is a 2,2'-bipyridine ligand attached to bis-polyethylene glycol chains, for the treatment of bacterial infections. The AIE phenomenon of the complexes leveraged for detecting bacteria by fluorescence microscopy imaging that displayed a strong red emission in Gram-positive bacteria. The antibacterial activity of the complexes assessed against Gram-positive methicillin-sensitive S. aureus, methicillin-resistant S. aureus, E.faecium and E.faecalis and Gram-negative E. coli and P.aeruginosa bacteria of clinical interest. The complexes Ir2-Ir4 exerted potent antibacterial activity towards Gram-positive strains with low minimum inhibitory concentrations (MICs) values in the range of 1-9 μM, which is comparable to clinically approved antibiotic vancomycin. In contrast, these complexes were found to be inactive towards Gram-negative bacterial strains (MICs > 100 µM). The mechanism of antibacterial activity of the complexes implies that ROS generation, membrane depolarization and rupture are responsible for bacterial cell death. Further, the complexes Ir1-Ir3 were found to be low-toxic against human red blood cells and human embryonic kidney (HEK293) cells, indicating their potential for use as antibacterial agents.

Pillar[5]arene stabilized gold nanoparticles for the enhanced light-triggered nitric oxide release with antibacterial and antibiofilm activities

The reactivity of guests confined in well-defined host cavities act significantly different from that in bulk systems. In this work, pillar[5]arene not only works as a stabilizer for the fabrication of gold nanoparticles, but also act as an accelerator for the enhanced photo-triggered release of gaseous nitric oxide (NO) from encapsulated NO donor. The host–guest complex can dramatically improve the photoactivity of loaded guest molecule to generate antibacterial NO molecules through the confinement effect of pillar[5]arene cavity. The synergistic photo-triggered localized NO release and photo-thermal effect of host–guest complex demonstrated impressive antibacterial behaviors against Gram-negative bacterial strain Escherichia coli, Gram-positive bacterial strain Staphylococcus aureus and methicillin-resistant Staphylococcus aureus. Moreover, this biocompatible photo-responsive complex can also inhibit bacterial biofilm formation and disrupt the pre-existing biofilms.

Novel tetrazolyl-1,2,3-triazole derivatives as potent antimicrobial targets: design, synthesis and molecular docking techniques

The main objective of this study is to produce novel triazoles–loaded tetrazoles, which are crucial in the development of prospective therapeutic agents in medicinal chemistry. Recent investigations have found a wide range of uses for these derivatives, and they are prospective lead molecules for the synthesis of substances with enormous therapeutic utility for various diseases, especially for bacterial therapy. New series of 1,2,3-triazole derivatives have been synthesized from methyl (2S,4S)-4-azido-1-(2,4-difluoro-3-methylbenzoyl)pyrrolidine-2-carboxylate (5) using a well–established click reaction that has several advantages to afford a novel heterocyclic compound based on tetrazole moieties. The structures of the new compounds were ascertained by spectral means (IR, NMR: 1H and 13C) and mass spectrum. All the synthesized compounds were assessed in vitro antimicrobial activity against Gram-+ve (S. pyogenes, S. aureus and B. subtilis), Gram-negative (E. coli and P. aeruginosa) bacterial and fungal strains A. flavus and C. albicans. The prepared compounds 7b and7f proved to have strong impact on S. aureus and S. pyogenes strains with MICs of 2.5 µg/mL and 1.5 µg/mL respectively. Among the tested compounds, hybrids 7b, 7f, 7h, and 7i exhibited exceptional antifungal susceptibilities against C. albicans with zone of inhibition 25 ± 0.2, 30 ± 0.3, 30 ± 0.1, and 28 ± 0.2 mm respectively, which is stronger than fluconazole (28 ± 0.1 mm). The capacity of ligand 7f to form a stable compound on the active site of S. aureus complex with DNA Gyrase (2XCT) was confirmed by docking studies using amino acids Ala233(A), Arg234(A), Gly283(A), Ser286(A), Lys52(A), His280(A), Gly51(A), His282(A) and Val246(A). Furthermore, the physicochemical and ADME (absorption, distribution, metabolism, and excretion) filtration molecular properties, estimation of toxicity, and bioactivity scores of these scaffolds were evaluated.

Engineering of self-assembled silver-peptide colloidal nanohybrids with enhanced biocompatibility and antibacterial activity

Several bacterial strains have developed resistance against commercial antibiotics, and interestingly, supramolecular nanomaterials have shown considerable advantages for antibacterial applications. However, the main challenges in adopting nanotechnology for antibacterial studies are random aggregation, compromised toxicity, multi-step preparation approaches, and unclear structure-function properties. Herein, we designed the amphiphilic tripeptide that acts as a reducing and capping agent for silver metal to form silver-peptide colloidal nanohybrids with the mild assistance of UV light (254 nm) through the photochemical reduction method. The nanohybrids are characterized by different spectroscopic and microscopic techniques, and non-covalent molecular interactions between metal and peptide building blocks confirm their central role in the formation of nanohybrids. The tripeptide is biocompatible and can reduce the toxicity of silver ions (Ag+) by reducing to Ag0. These colloidal nanohybrids showed antibacterial activity against gram-negative and gram-positive bacterial strains, and the possible mechanism of killing bacterial cells could be membrane disruption. This synthetic strategy is facile and green, which helps avoid using toxic chemicals or reagents and complicated methods for colloidal nanohybrid preparation for biomedical applications.

Carbapenem resistance in gram-negative pathogens in an Iranian hospital: high prevalence of OXA-type carbapenemase genes.

The widespread dissemination of carbapenem-resistant Gram-negative bacteria poses a significant threat to global public health. This study aimed to investigate the prevalence of carbapenem resistance in Gram-negative bacteria isolated from patients at the Children's Medical Center Hospital, Tehran, Iran, to understand the molecular mechanisms underlying this resistance. During the period spanning from June 2019 to June 2020, 777 Gram-negative bacterial strains were isolated. Antibiotic susceptibility testing was performed according to Clinical and Laboratory Standards Institute. Polymerase chain reaction was used to detect carbapenem resistance genes including bla OXA23, bla OXA24, bla OXA48, bla OXA51, bla OXA58, bla OXA143, bla KPC, bla IMP, bla VIM, and bla NDM. Among the total bacterial isolates, 141 (18.1%) exhibited carbapenem resistance. Escherichia coli was the most prevalent (57.4%), followed by Klebsiella pneumoniae (11.3%) and Acinetobacter baumannii (10.6%). Other notable contributors included Enterobacter spp. (5.7%), Salmonella spp. (3.5%), and Stenotrophomonas maltophilia (2.8%). Citrobacter spp., Proteus mirabilis, and Pseudomonas aeruginosa contributed to the distributions of two, one, and three isolates, respectively. Notably, bla OXA48 showed the highest prevalence (33%), followed by bla OXA143 and bla OXA58 (27% and 24%, respectively). In addition, bla OXA24 was present in 11% of the total isolates, bla OXA23 in 10%, and bla NDM in 10%, whereas bla KPC, bla VIM, and bla IMP were not detected. Our study highlights the prevalence of carbapenemase-producing Gram-negative isolates among pediatric patients. Notable resistance patterns, especially in K. pneumoniae and E. coli, underline the urgent need for proactive interventions, including appropriate antibiotic prescription practices and strengthening of antibiotic stewardship programs.

Investigation of pure and Sn-doped Ca(OH)2 nanoparticles for optical and biomedical applications

The present study explores the synthesis and characterization of pure and Sn-doped Ca(OH)2 nanoparticles, highlighting their potential for optical and biomedical applications. The incorporation of Sn into the Ca(OH)2 matrix is investigated for the first time, providing insights into its impact on the structural, optical, and biological properties of the nanoparticles. A straightforward precipitation method was employed to synthesize pure and Sn-doped calcium hydroxide nanoparticles. The synthesized nanoparticles were characterized by using X-ray diffraction (XRD) pattern, ultraviolet–visible–near infrared (UV-Vis-NIR) spectra, Fourier Scanning Electron Microscope (FESEM) micrographs, and agar well diffusion method for antibacterial study. X-ray diffraction examinations confirmed the polycrystalline nature of the Ca(OH)2 nanoparticles and revealed the structure to be hexagonal. The average crystallite size of the pure and Sn-doped Ca(OH)2 nanoparticles are 49 nm and 66 nm, respectively. The FESEM images of the sample revealed the formation of pure Ca(OH)2 nanoparticles in the form of nanoflakes and the change in the morphology while doping Sn with Ca(OH)2. The prepared samples were assessed using UV-Vis-NIR spectra, showing the UV absorption band at approximately 247 and 263 nm for the samples of pure and Sn-doped Ca(OH)2 nanoparticles, respectively. The calculated direct and indirect allowed band gap energies were found to be 4.04 and 3.92 eV for pure Ca(OH)2, and 3.37 and 2.94 eV in the case of Sn-doped Ca(OH)2. The antibacterial effectiveness of Ca(OH)2 nanoparticles was assessed using the well diffusion method, and it was observed that both the samples of pure and Sn doped Ca(OH)2 nanoparticles exhibited significant antibacterial properties against gram-negative bacterial strains. An elevation in Minimum Inhibitory Concentration (MIC) values for Sn-doped Ca(OH)2 nanoparticles compared to pure Ca(OH)2 nanoparticles was observed when examining their impact on Gram-negative bacteria (Klebsiella pneumoniae), which suggested a requirement for a higher concentration due to the nature of surface charges present in order to inhibit the growth of microorganisms.

Investigating antibacterial and anti-inflammatory properties of synthetic curcuminoids.

The concept of intratumoral microbiota is gaining attention in current research. Tumor-associated microbiota can activate oncogenic signaling pathways such as NF-κB, thereby promoting tumor development and progression. Numerous studies have demonstrated that curcumin and its analogs possess strong antitumor effects by targeting the NF-κB signaling pathway, along with potent antibacterial properties. In this study, we tested the antibacterial activity of two curcuminoids, Py-cPen and V-cPen, against the Gram-negative bacterial strains Pseudomonas aeruginosa and Escherichia coli and the Gram-positive bacterial strain Streptococcus aureus using in vitro assays and fluorescent microscopy. We observed that both Py-cPen and V-cPen reduced NF-κB activation upon lipopolysacharide (LPS) challenge in cell assays. In addition, our findings indicate that Py-cPen and V-cPen interact with LPS, as demonstrated by transmission electron microscopy and confirmed using in silico analyses, thereby modulating LPS activity. Overall, our data indicate that Py-cPen and V-cPen exhibit strong antibacterial and antiinflammatory properties, suggesting their potential as candidates for new multitarget therapeutic strategies.

Investigation of antibacterial and anticancer activities of biosynthesized metal-doped and undoped zinc oxide nanoparticles.

Over the past 10 years, nanotechnology has emerged as a very promising technique for a wide range of biomedical applications. Green synthesized metal and metal oxide nanoparticles (NPs) are cheap, easy to produce in large quantities, and safe for the environment. Currently, efforts are being made to dope ZnO in order to improve its optical, electrical, and ferromagnetic qualities as well as its crystallographic quality. Actually, doping is one of the simplest methods for enhancing an NP's physicochemical characteristics because it involves introducing impure ions into the crystal lattice of the particle. In this study, the biosynthesis of zinc oxide NPs (ZnONPs) and metal-doped (Mg2+ and Ag+) ZnONPs was carried out by using aqueous and water-alcoholic extracts of Cynara scolymus L. leaves, Carthamus tinctorius L. flowers, and Rheum ribes L. (RrL) plant, which are rich in phytochemical content. Plant extracts act as a natural reducing, capping, and stabilizing agent in the production. The produced NPs were characterized using a variety of methods, such as ultraviolet-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM). The produced metal-doped and undoped ZnONPs exhibited characteristic absorption peaks between 365 and 383nm due to their surface plasmon resonance bands. SEM analysis revealed that the NPs were oval, nearly spherical, and spherical. In the FTIR spectra, the Zn-O bonding peak ranges from 400 to 700cm-1. The peaks obtained in the range of 407-562cm-1 clearly represent the Zn-O bond. In addition, the FTIR results showed that there were notable amounts of phenol and flavonoid compounds in both the prepared extract and ZnONPs. According to DLS analysis results, the size distribution of produced NPs is between 120 and 786nm. The antibacterial properties of green produced NPs on Gram-positive (Staphylococcus aureus RN4220) and Gram-negative (Escherichia coli DH10B) bacterial strains were investigated by agar well diffusion method. In studies investigating the anticancer activities of biosynthesized NPs, mouse fibroblast cells (L929) were used as healthy cells and human cervical cancer cells (HeLa) were used as cancer cells. Only the produced Ag-ZnONPs showed potent dose-dependent antibacterial activity (at concentrations higher than 100µg/mL) against Gram-positive and Gram-negative bacteria. RrL-ZnONP-600 and RrL-ZnONP-800 NPs produced with water-ethanol extract of RrL plant and calcined at 600 and 800°C were effective at high concentrations in healthy cells and at low concentrations in HeLa cancer cells, showing that they have the potential to be anticancer agents. The study's findings highlight the potential of green synthesis techniques in the production of medicinal nanomaterials for the treatment of cancer and other biological uses.

Biofabricated silver nanoparticles from Calotropis procera: A potential antimicrobial solution against pathogenic bacteria

Calotropis procera has the potential as a traditional medicinal plant that offers a diverse array of healing treatments. It was used in conventional medicine to remedy several ailments, including diarrhea and snakebites. This study examines the antibacterial properties of silver nanoparticles derived from the floral and latex components of C. procera. The nanoparticles were tested for their effectiveness against Gram-negative and Gram-positive bacterial strains. For characterization, the synthesized nanoparticles underwent thorough analysis using UV spectroscopy, fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). After the reduction process, the FTIR analysis revealed that some functional biomolecules found in plants form a coating on the nanoparticles, serving as organic agents that stabilize the nanoparticles. The size of nanoparticles analyzed with SEM falls in the 30 to 130 nm range. Furthermore, the synthesized silver nanoparticles were tested as antimicrobial agents against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa, well-known microorganisms that can produce ulceration phases and severe health consequences. After a comprehensive examination, it was found that the silver nanoparticles have significant antibacterial effectiveness, particularly against S. aureus, a primary bacterium responsible for causing different ailments. The remarkable antibacterial efficacy of the silver nanoparticles synthesized in an environment-friendly manner underscores its potential applications in combating the evolution of antibiotic-resistant strains.