Antibiotic resistance

A Comparative Study of the Inhibitory Action of Berberine Derivatives on the Recombinant Protein FtsZ of E. coli

Medicinal plants belonging to the genus Berberis may be considered an interesting source of drugs to counteract the problem of antimicrobial multiresistance. The important properties associated with this genus are mainly due to the presence of berberine, an alkaloid with a benzyltetrahydroisoquinoline structure. Berberine is active against both Gram-negative and Gram-positive bacteria, influencing DNA duplication, RNA transcription, protein synthesis, and the integrity of the cell surface structure. Countless studies have shown the enhancement of these beneficial effects following the synthesis of different berberine analogues. Recently, a possible interaction between berberine derivatives and the FtsZ protein was predicted through molecular docking simulations. FtsZ is a highly conserved protein essential for the first step of cell division in bacteria. The importance of FtsZ for the growth of numerous bacterial species and its high conservation make it a perfect candidate for the development of broad-spectrum inhibitors. In this work, we investigate the inhibition mechanisms of the recombinant FtsZ of Escherichia coli by different N-arylmethyl benzodioxolethylamines as berberine simplified analogues appropriately designed to evaluate the effect of structural changes on the interaction with the enzyme. All the compounds determine the inhibition of FtsZ GTPase activity by different mechanisms. The tertiary amine 1c proved to be the best competitive inhibitor, as it causes a remarkable increase in FtsZ Km (at 40 μM) and a drastic reduction in its assembly capabilities. Moreover, a fluorescence spectroscopic analysis carried out on 1c demonstrated its strong interaction with FtsZ (Kd = 26.6 nM). The in vitro results were in agreement with docking simulation studies.

Glycosylation and Lipidation Strategies: Approaches for Improving Antimicrobial Peptide Efficacy

Antimicrobial peptides (AMPs) have recently gained attention as a viable solution for combatting antibiotic resistance due to their numerous advantages, including their broad-spectrum activity, low propensity for inducing resistance, and low cytotoxicity. Unfortunately, their clinical application is limited due to their short half-life and susceptibility to proteolytic cleavage by serum proteases. Indeed, several chemical strategies, such as peptide cyclization, N-methylation, PEGylation, glycosylation, and lipidation, are widely used for overcoming these issues. This review describes how lipidation and glycosylation are commonly used to increase AMPs’ efficacy and engineer novel AMP-based delivery systems. The glycosylation of AMPs, which involves the conjugation of sugar moieties such as glucose and N-acetyl galactosamine, modulates their pharmacokinetic and pharmacodynamic properties, improves their antimicrobial activity, and reduces their interaction with mammalian cells, thereby increasing selectivity toward bacterial membranes. In the same way, lipidation of AMPs, which involves the covalent addition of fatty acids, has a significant impact on their therapeutic index by influencing their physicochemical properties and interaction with bacterial and mammalian membranes. This review highlights the possibility of using glycosylation and lipidation strategies to increase the efficacy and activity of conventional AMPs.

Probiotics Mediate Intestinal Microbiome and Microbiota-Derived Metabolites Regulating the Growth and Immunity of Rainbow Trout (Oncorhynchus mykiss)

Emerging evidence confirms using probiotics in promoting growth and immunity of farmed fish. However, the molecular mechanisms underlying the host-microbiome interactions mediated by probiotics are not fully understood. In this study, we used rainbow trout (Oncorhynchus mykiss) as a model to investigate the internal mechanisms of host-microbiome interactions influenced by two probiotic bacteria, Bacillus velezensis and Lactobacillus sakei. We carried out experiments, including intestinal histology, serum physiology, and transcriptome and combined intestinal microbiome and metabolite profiling. Our results showed that both probiotics had a positive effect on growth, immunity, serum enzyme activity, the gut microbiome, and resistance to Aeromonas salmonicida in rainbow trout. Moreover, the intestinal microbial structure was reshaped with increased relative abundance of potential beneficial bacteria, such as Ruminococcus, Lachnospiraceae ucg-004, Leptotrichia, Bacillus coagulans, Porphyromonadaceae, Anaerococcus, and Photobacterium in the B. velezensis group and Paenibacillaceae and Eubacterium hallii in the L. sakei group. Metabolomic profiling and transcriptome analysis revealed upregulated metabolites as biomarkers, i.e., sucrose and l-malic acid in the B. velezensis group, and N-acetyl-l-phenylalanine, N-acetylneuraminic acid, and hydroxyproline in the L. sakei group. Additionally, a multiomics combined analysis illustrated significant positive correlations between the relative abundance of microflora, metabolites, and gene expression associated with immunity and growth. This study highlights the significant role of probiotics as effectors of intestinal microbial activity and shows that different probiotics can have a species-specific effect on the physiological regulation of the host. These findings contribute to a better understanding of the complex host-microbiome interactions in rainbow trout and may have implications for the use of probiotics in aquaculture. IMPORTANCE Probiotics are kinds of beneficial live microbes that impart beneficial effects on the host. Recent studies have proven that when given supplementation with probiotics, farmed fish showed improved disease prevention and growth promotion. However, the underlying metabolic functions regarding their involvement in regulating growth phenotypes, nutrient utilization, and immune response are not yet well understood in the aquaculture field. Given the active interactions between the gut microbiota and fish immune and growth performance, we conducted the supplementation experiments with the probiotics Bacillus velezensis and Lactobacillus sakei. The results showed that probiotics mediated intestinal microbiome- and microbiota-derived metabolites regulating the growth and immunity of fish, and different probiotics participated in the species-specific physiological regulation of the host. This study contributed to a better understanding of the functional interactions associated with host health and gut microbiota species.

Global, regional, and national incidence and mortality of neonatal sepsis and other neonatal infections, 1990–2019

Background

Neonatal infections, especially neonatal sepsis, are one of the major causes of incidence and mortality in pediatrics. However, the global burden of neonatal sepsis and other neonatal infections (NSNIs) remains unclear.

Methods

From the 2019 global disease burden study, we collected annual incident cases, deaths, age-standardized incidence rates (ASIRs), and age-standardized deaths rates (ASDRs) of NSNIs in the past 30 years. Analysis indicators included the percentage of relative changes in incident cases and deaths, and the estimated annual percentage changes (EAPCs) of ASIRs and ASDRs. Correlations were assessed between the EAPCs of ASIRs and ASDRs and social evaluation indicators, including sociodemographic index (SDI) and universal health coverage index (UHCI).

Results

Globally, the number of incident cases of NSNIs grew by 12.79% per year, and the number of deaths dropped by 12.93% per year. During this period, global ASIR of NSNIs increased by 46% annually on average, while ASDR decreased by 53% annually on average. The ASIR and ASDR of female NSNIs were consistently lower than that of male NSNIs. The EAPC of female ASIR was 0.61, nearly twice that of male ASIR, and female ASIR was growing rapidly. The same declining trends of ASDR were noted in males and females. The ASIR of NSNIs in high-SDI regions grew by an average of 14% annually from 1990 to 2019. Except for high-SDI regions, the ASIRs of other 4 SDI regions maintained a rising trend at a high level, and were improved in the past 10 years. The ASDRs of all 5 SDI regions generally showed a downward trend. The region with the highest ASIR of NSNIs was Andean Latin America, and Western Sub-Saharan Africa had the highest mortality. We found a negative correlation between EAPCs of ASDRs and UHCI in 2019.

Conclusion

The global health situation was still not optimal. The incidence of NSNIs remained high, and continues to rise. The mortality of NSNIs has decreased, especially in the countries/territories with high UHCI. Therefore, it is crucial to improve the overall awareness and management of NSNIs, and take interventions for NSNIs worldwide.

Antibacterial Activity and Cytocompatibility of Electrospun PLGA Scaffolds Surface-Modified by Pulsed DC Magnetron Co-Sputtering of Copper and Titanium

Biocompatible poly(lactide-co-glycolide) scaffolds fabricated via electrospinning are having promising properties as implants for the regeneration of fast-growing tissues, which are able to degrade in the body. The hereby-presented research work investigates the surface modification of these scaffolds in order to improve antibacterial properties of this type of scaffolds, as it can increase their application possibilities in medicine. Therefore, the scaffolds were surface-modified by means of pulsed direct current magnetron co-sputtering of copper and titanium targets in an inert atmosphere of argon. In order to obtain different amounts of copper and titanium in the resulting coatings, three different surface-modified scaffold samples were produced by changing the magnetron sputtering process parameters. The success of the antibacterial properties’ improvement was tested with the methicillin-resistant bacterium Staphylococcus aureus. In addition, the resulting cell toxicity of the surface modification by copper and titanium was examined using mouse embryonic and human gingival fibroblasts. As a result, the scaffold samples surface-modified with the highest copper to titanium ratio show the best antibacterial properties and no toxicity against mouse fibroblasts, but have a toxic effect to human gingival fibroblasts. The scaffold samples with the lowest copper to titanium ratio display no antibacterial effect and toxicity. The optimal poly(lactide-co-glycolide) scaffold sample is surface-modified with a medium ratio of copper and titanium that has antibacterial properties and is non-toxic to both cell cultures.

Electroresponsive and pH-Sensitive Hydrogel as Carrier for Controlled Chloramphenicol Release

Multiresponsive hydrogels, which are smart soft materials that respond to more than one external stimulus, have emerged as powerful tools for biomedical applications, such as drug delivery. Within this context and with the aim of eliminating the systematic administration of antibiotics, special attention is being paid to the development of systems for controlled delivery of antibiotic for topical treatment of bacterial infections. In this work, an electro-chemo responsive hydrogel able to release chloramphenicol (CAM), a broad spectrum antibiotic also used for anticancer therapy, is proposed. This has been prepared by grafting poly(acrylic acid) (PAA) to sodium alginate (Alg) and in situ encapsulation of poly(3,4-ethylenedioxythiophene) nanoparticles loaded with CAM (PEDOT/CAM NPs), which were obtained by emulsion polymerization. Although the response to electrical stimuli of PEDOT was the main control for the release of CAM from PEDOT/CAM NPs, the release by passive diffusion had a relatively important contribution. Conversely, the passive release of antibiotic from the whole engineered hydrogel system, Alg-g-PAA/PEDOT/CAM, was negligible, whereas significant release was achieved under electrostimulation in an acid environment. Bacterial tests and assays with cancer cells demonstrated that the biological activity of CAM remained after release by electrical stimulation. Notably, the successful dual-response of the developed hydrogel to electrical stimuli and pH changes evidence the great prospect of this smart material in the biomedical field, as a tool to fight against bacterial infections and to provide local cancer treatment.

Genomic, Molecular, and Phenotypic Characterization of Arthrobacter sp. OVS8, an Endophytic Bacterium Isolated from and Contributing to the Bioactive Compound Content of the Essential Oil of the Medicinal Plant Origanum vulgare L

Medicinal plants play an important role in the discovery of new bioactive compounds with antimicrobial activity, thanks to their pharmacological properties. However, members of their microbiota can also synthesize bioactive molecules. Among these, strains belonging to the genera Arthrobacter are commonly found associated with the plant's microenvironments, showing plant growth-promoting (PGP) activity and bioremediation properties. However, their role as antimicrobial secondary metabolite producers has not been fully explored. The aim of this work was to characterize the Arthrobacter sp. OVS8 endophytic strain, isolated from the medicinal plant Origanum vulgare L., from molecular and phenotypic viewpoints to evaluate its adaptation and influence on the plant internal microenvironments and its potential as a producer of antibacterial volatile molecules (VOCs). Results obtained from the phenotypic and genomic characterization highlight its ability to produce volatile antimicrobials effective against multidrug-resistant (MDR) human pathogens and its putative PGP role as a producer of siderophores and degrader of organic and inorganic pollutants. The outcomes presented in this work identify Arthrobacter sp. OVS8 as an excellent starting point toward the exploitation of bacterial endophytes as antibiotics sources.

Naturopathic Management of Acute Pediatric Respiratory Infections: A Modified Delphi Study

Objective: Both the United Nations and the World Health Organization have identified antimicrobial resistance as a significant threat to global health. The Centers for Disease Control and Prevention identified five pediatric respiratory conditions as requiring particular scrutiny in terms of antibiotic stewardship. This study sought to identify strategies used by experienced naturopathic practitioners to treat acute respiratory infections in children. The authors theorize that naturopathic strategies safely fill the gap between watchful waiting and antibiotic prescription, thus reducing the use of antibiotics. Methods: Naturopathic practitioners in Canada, the United States, and Australia with a minimum of 5 years of experience in clinical naturopathic care of children were recruited for a modified Delphi study. A 14-person panel of practitioners was selected to complete a series of four iterative surveys assessing agreement to statements in five domains of knowledge/attitudes, assessment/diagnosis, management, monitoring, and education. Items were deemed to have reached consensus if they reached a predetermined threshold of 70% agreement, or failed to reach a threshold of 40% agreement. Items between these boundaries were modified and retested until either consensus was reached or the four surveys had been completed. Results: Results yielded a large degree of agreement on core naturopathic approaches to the management of acute pediatric respiratory infections, especially lifestyle strategies, including adequate rest and dietary recommendations. The use of vitamins C and D was strongly supported, as were herbs, particularly echinacea and elderberry. Some hydrotherapy and topical applications specific to the individual focus on infection also reached consensus. Results suggested that most respondents, even if they have the authority to prescribe antibiotics, rarely deem it necessary to do so. Conclusion: Findings of this study provide (1) clarity on the role of naturopathic doctors in the management of pediatric health concerns and the stewardship of antibiotics; and (2) initial guidance to less experienced naturopathic practitioners. The findings also identify key priorities for research into the safety and effectiveness of naturopathic interventions to reduce the unnecessary prescribing of antibiotics.

Different bile acids have versatile effects on sporulation, toxin levels and biofilm formation of different Clostridioides difficile strains

Clostridioides difficile infection develops following ingestion of virulent stains by a susceptible host. Once germinated, toxins TcdA and TcdB, and in some of the strains binary toxin, are secreted, eliciting disease. Bile acids play a significant role in the process of spore germination and outgrowth, with cholate and its derivative enhancing colony formation, while chenodeoxycholate inhibit germination and outgrowth. This work investigated bile acids' impact on spore germination, toxin levels and biofilm formation in various strain types (STs). Thirty C. difficile isolates (A⁺ B⁺ CDT^-\+) of different STs were exposed to increasing concentrations of the bile acids, cholic acid (CA), taurocholic acid (TCA) and chenodeoxycholic acid (CDCA). Following treatments, spore germination was determined. Toxin concentrations were semi-quantified using the C. Diff Tox A/B II™ kit. Biofilm formation was detected by the microplate assay with crystal violet. SYTO® 9 and propidium iodide staining were used for live and dead cell detection, respectively, inside the biofilm. Toxins levels were increased by 1.5-28-fold in response to CA and by 1.5-20-fold in response to TCA, and decreased by 1-37-fold due to CDCA exposure. CA had a concentration-dependent effect on biofilm formation, with the low concentration (0.1%) inducing- and the higher concentrations inhibiting biofilm formation, while CDCA significantly reduced biofilm production at all concentrations. There were no differences in the bile acids effects on different STs. Further investigation might identify a specific bile acids' combination with inhibitory effects on C. difficile toxin and biofilm production, which could modulate toxin formation to reduce the likelihood of developing CDI.

Involvement of RNA chaperone Hfq in the regulation of antibiotic resistance and virulence in Shigella sonnei

The host factor for RNA phage Qβ replicase (Hfq) is a crucial post-transcriptional regulator in many bacterial pathogens, facilitating the interaction between small non-coding RNAs (sRNAs) and their target mRNAs. Studies have suggested that Hfq plays a role in antibiotic resistance and virulence in bacteria, although its functions in Shigella are not fully understood. In this study, we investigated the functional roles of Hfq in Shigella sonnei (S. sonnei) by constructing an hfq deletion mutant. Our phenotypic assays showed that the hfq deletion mutant was more sensitivity to antibiotics and had impaired virulence. Transcriptome analyses supported the results concerning the phenotype of the hfq mutant and showed that differentially expressed genes were mainly enriched in the KEGG pathways two-component system, ABC transporters, ribosome, and Escherichia coli biofilm formation. Additionally, we predicted eleven novel Hfq-dependent sRNAs, which were potentially involved in the regulation of antibiotic resistance and/or virulence in S. sonnei. Our findings suggest that Hfq plays a post-transcriptional role in regulating antibiotic resistance and virulence in S. sonnei, and could provide a basis for future studies on Hfq-sRNA-mRNA regulatory networks in this important pathogen.

An indolizine squaraine-based water-soluble NIR dye for fluorescence imaging of multidrug-resistant bacteria and antibacterial/antibiofilm activity using the photothermal effect

The majority of nosocomial infections are caused by bacteria with antimicrobial resistance and the formation of biofilms, such as implant-related bacterial infections and sepsis. There is an urgent need to develop new strategies for early-stage screening, destruction of multidrug-resistant bacteria, and efficient inhibition of biofilms. Organic dyes that absorb and emit in the near-infrared (NIR) region are potentially non-invasive, high-resolution, and rapid biological imaging materials. In this study, a non-toxic and biocompatible indolizine squaraine dye with water-solubilizing sulfonate groups (SO₃SQ) is studied for bacterial imaging and photothermal therapy (PTT). PTT is efficient in eliminating microorganisms through local hyperthermia without the risk of developing drug-resistant bacteria. The optical properties of SO₃SQ are studied extensively in phosphate-buffered saline (PBS). UV-Vis-NIR absorption spectra analysis shows a strong absorption between 650 nm - 1000 nm. SO₃SQ allows for the wash-free fluorescence imaging of drug-resistant bacteria via NIR fluorescence imaging due to a "turn-on" fluorescence property of the dye when interacting with bacteria. Although SO₃SQ exhibits no toxicity against both Gram-positive bacteria and Gram-negative bacteria, the PTT property of SO₃SQ is efficient in killing bacteria as well as inhibiting and eradicating biofilms. PTT experiments demonstrate that SO₃SQ reduces 90% of cell viability in bacterial strains under NIR radiation with a minimum inhibition concentration (MIC₉₀) of >450 μg/mL. The PTT property of SO₃SQ can also inhibit biofilms (BIC₉₀ = 1000-2000 μg/mL) and eradicate both preformed young and mature biofilms (MBEC₉₀ = 1500-2000 μg/mL) as observed by crystal violet assays.

A Novel Strategy for the Design of Aurein 1.2 Analogs with Enhanced Bioactivities by Conjunction of Cell-Penetrating Regions

The rational design modification of membrane-active peptide structures by introducing additional membrane-penetrating regions has become a good strategy for the improvement of action and potency. Aurein 1.2 (GLFDIIKKIAESF-NH2) is a multifunctional antimicrobial peptide isolated from the green and golden bell frog, Litoria aurea, and the southern bell frog Litoria raniformis skin secretions. Its bio-functionality has been widely investigated. However, its lack of a potent action failed to provide aurein 1.2 with a competitive edge for further development as a therapeutic agent for clinical use. Herein, aurein 1.2 was chosen as a template for rational modification to achieve a more potent bio-functionality. KLA-2 (GLFDIIKKLAKLAESF-NH2), which a double KLA region inserted into the sequence, presented a 2-16-fold enhancement of antimicrobial activity, a 2-8-fold greater anti-biofilm activity (including biofilm prevention and eradication), and a 7-fold more potent anti-proliferation activity and hence was regarded as the most broad-spectrum active peptide. Additionally, with respect to antimicrobial activity, the IIKK-modified analog, IK-3 (GLFDIIKKIIKKIIKKI-NH2), also demonstrated a potent enhancement of activity against various pathogens, exhibiting a 2-8-fold enhanced activity compared to the parent peptide. Moreover, the selectivities of KLA-1 and KLA-2 were enhanced significantly. In conclusion, peptide modification, through the introduction of additional membrane penetrating regions, can increase both the potency and activity spectra of natural template peptides, making them suitable candidates for new drug development.

Polymer Blends Based on 1-Hexadecyl-3-methyl Imidazolium 1,3-Dimethyl 5-Sulfoisophthalate Ionic Liquid: Thermo-Mechanical, Surface Morphology and Antibacterial Properties

In this study, antibacterial polymer blends based on Polyvinyl Chloride (PVC) and Polystyrene-Ethylene-Butylene-Styrene (SEBS), loaded with the ionic liquid (IL) 1-hexadecyl-3-methyl imidazolium 1,3-dimethyl 5-sulfoisophthalate (HdmimDMSIP) at three different concentrations (1%, 5%, and 10%), were produced. The IL/blends were characterized by their thermo-mechanical properties, surface morphology, and wettability. IL release from the blends was also evaluated. The agar diffusion method was used to test the antibacterial activity of the blends against Staphylococcus epidermidis and Escherichia coli. Results from thermal analyses showed compatibility between the IL and the PVC matrix, while phase separation in the SEBS/IL blends was observed. These results were confirmed using PY-GC MS data. SEM analyses highlighted abundant IL deposition on PVC blend film surfaces containing the IL at 5-10% concentrations, whereas the SEBS blend film surfaces showed irregular structures similar to islands of different sizes. Data on water contact angle proved that the loading of the IL into both polymer matrices induced higher wettability of the blends' surfaces, mostly in the SEBS films. The mechanical analyses evidenced a lowering of Young's Modulus, Tensile Stress, and Strain at Break in the SEBS blends, according to IL concentration. The PVC/IL blends showed a similar trend, but with an increase in the Strain at Break as IL concentration in the blends increased. Both PVC/IL and SEBS/IL blends displayed the best performance against Staphylococcus epidermidis, being active at low concentration (1%), whereas the antimicrobial activity against Escherichia coli was lower than that of S. epidermidis. Release data highlighted an IL dose-dependent release. These results are promising for a versatile use of these antimicrobial polymers in a variety of fields.

Combined effects of sodium butyrate and xylo-oligosaccharide on growth performance, anti-inflammatory and antioxidant capacity, intestinal morphology and microbiota of broilers at early stage

This study aimed to evaluate the individual and combined effects of chemically protected sodium butyrate (CSB) and xylo-oligosaccharide (XOS) on performance, anti-inflammatory and antioxidant capacity, intestinal morphology and microbiota of broilers. A total of 280 one-day-old Arbor Acres broilers were randomly distributed into 5 treatments: basal diet (CON), basal diet supplemented with 100 mg/kg aureomycin and 8 mg/kg enramycin (ABX), 1000 mg/kg CSB (CSB), 100 mg/kg XOS (XOS), and mixture of 1000 mg/kg CSB and 100 mg/kg XOS (MIX), respectively. On d 21, ABX, CSB, and MIX decreased feed conversion ratio compared with CON (CON: ABX: CSB: MIX = 1.29: 1.22: 1.22: 1.22), whereas body weight of CSB and MIX was increased by 6.00% and 7.93%, and average daily gain was increased by 6.62% and 8.67% at 1-21 d, respectively (P < 0.05). The main effect analysis showed that both CSB and XOS treatments increased ileal villus height and villus height to crypt depth ratio (VCR) (P < 0.05). Moreover, broilers in ABX showed lower 21.39% ileal crypt depth and higher 31.43% VCR than those in CON (P < 0.05). Dietary CSB and XOS were added individually or collectively increased total antioxidant capacity and superoxide dismutase, and anti-inflammatory cytokines interleukin-10 and transforming growth factor-β, whereas decreased malondialdehyde, and proinflammatory cytokines IL-6 and tumor necrosis factor-α content in serum (P < 0.05). Meanwhile, MIX showed the best effect of antioxidant and anti-inflammatory capacity among the 5 groups (P < 0.05). There was an interaction between CSB and XOS treatments on increasing cecal acetic acid, propionic acid, butyric acid and total short-chain fatty acid (SCFA) (P < 0.05), and the one-way ANOVA showed that propionic acid in CSB was 1.54 times that of CON, whereas butyric acid and total SCFAs in XOS were 1.22 times and 1.28 times that of CON, respectively (P < 0.05). Furthermore, dietary combination of CSB and XOS changed phyla Firmicutes and Bacteroidota, and increased genera Romboutsia and Bacteroides (P < 0.05). In conclusion, dietary CSB and XOS improved growth performance of broilers, and the combined addition of them had the best effect on anti-inflammatory and antioxidant capacity, and intestinal homeostasis of broilers in current study, indicating that it may be a potential natural alternative to antibiotics.

Hybrid Nanosystems of Antibiotics with Metal Nanoparticles-Novel Antibacterial Agents

The appearance and increasing number of microorganisms resistant to the action of antibiotics is one of the global problems of the 21st century. Already, the duration of therapeutic treatment and mortality from infectious diseases caused by pathogenic microorganisms have increased significantly over the last few decades. Nanoscale inorganic materials (metals and metal oxides) with antimicrobial potential are a promising solution to this problem. Here we discuss possible mechanisms of pathogenic microorganisms' resistance to antibiotics, proposed mechanisms of action of inorganic nanoparticles on bacterial cells, and the possibilities and benefits of their combined use with antibacterial drugs. The prospects of using metal and metal oxide nanoparticles as carriers in targeted delivery systems for antibacterial compositions are also discussed.

Effect of dietary celery (Apium graveolens) on the growth performance, immune responses, and bacterial resistance against Vibrio anguillarum of European seabass (Dicentrarchus labrax)

In this study, we evaluated to reveal the effects of aqueous methanolic extract of celery (Apium graveolens) on the growth performance, immune responses, and resistance against Vibrio anguillarum in European seabass (Dicentrarchus labrax). For this purpose, twenty fish (initial mean weight of 4.80 ± 0.06 g) were placed into twelve tanks (400 L) in triplicate and fish were fed with control (C) and three different levels (0.01, 0.05, and 0.1 g/kg) of A. graveolens (AG) extract-containing diets (AG0.01, AG0.05, and AG0.1) for 30 days. Blood and tissue (kidney, spleen, and intestine) samples were taken from the fish every 10 days during the study to determine the immune responses of the fish. Respiratory burst activity (RBA) was significantly decreased in the AG0.1 group compared to all other groups on the 10th day of the study (P < 0.05). Significance was noticed in the RBA of fish in all AG groups compared to the C group (P < 0.05) on the 30th day of the experiment Lysozyme activity (LYS) was raised on the 10th day of the study in all celery groups compared to the C group (P < 0.05). No differences in the myeloperoxidase activity (MPO) were observed among the experimental groups (P > 0.05). The final mean weight (FMW) was not affected in any experimental groups (P > 0.05). However, in the AG0.05 group, the specific growth rate (SGR) increased, and the feed conversion ratio (FCR) decreased compared to other groups (P < 0.05). IL-1β in the kidney was highly elevated in the AG0.01 group on the 20th day of the study (P < 0.05). Similar results were observed on IL-6, IL-8, and TNF-α expression in the kidney (P < 0.05). Anti-inflammatory responses (IL-10 and TGF-β) also increased in all experimental groups and tissues compared to the C group (P < 0.05). COX-2 was upregulated on the 20th day of the study in all tissues (P < 0.05). At the end of the feeding trial, the survival rate of the AG0.1 group in fish infected with Vibrio anguillarum infection was higher than the C group. Dietary celery extract did not affect growth performance directly but increased innate immune responses and a high survival rate. Overall, compared to the control group, the growth, immunity, and resistance of European seabass fed with a diet containing 0.05 g/kg celery aqueous methanolic extract has been improved, and this could be used as an immunostimulant feed additive.

Eco-friendly synthesis of Ag-NPs using Endostemon viscosus (Lamiaceae): Antibacterial, antioxidant, larvicidal, photocatalytic dye degradation activity and toxicity in zebrafish embryos

Nanotechnology is a multidisciplinary area of study that has grown significantly in serving many functions and impacting human society. New fields of science have been facilitated by the clean, non-toxic, and biocompatible nature of plant-derived nanoparticles. The present study deals with the first green synthesis of silver nanoparticles (Ag-NPs) using Endostemon viscosus, and their synthesized Ag NPs were characterized by different spectral methods (UV-vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction Spectroscopy (XRD), Transmission Electron Microscopy (TEM) and Energy dispersive X-ray Spectroscopy (EDAX). The change initially observed the production of Ag-NPs in color from green to ash and then confirmed by SPR band at 435 nm in UV-vis spectral analysis. The FTIR findings indicate that many functional groups belong to the pharmaceutically useful phytochemicals, which interact as reducing, capping, and stabilizing agents in synthesizing silver nanoparticles. The predominant peaks in the XRD pattern belong to the planes 210°, 111°, 200°, 241°, and 311° and thus demonstrated the Ag-NPs FCC crystal structure. TEM analysis exhibited spherical-shaped particles with an average size of 13 nm, and the EDAX band showed a distinctive metallic silver peak at 3.0 keV. The antibacterial activity of Ag-NPs tested to show a maximum zone of inhibition of 19 mm for Staphylococcus aureus and 15 mm for Escherichia coli at 100 μg/mL, respectively. Bio-fabricated Ag-NPs were assessed for antioxidant activity (DPPH with % inhibition 57.54% and FRAP with % inhibition 70.89%). The biosynthesized Ag-NPs demonstrated potential larvicidal efficacy against Aedes aegypti with more than 90% at 250 μg/mL. Histological profiles were altered while treating with Ag-NPs at 250 μg/mL. The photocatalytic activity of synthesized E. viscosus Ag-NPs was tested against methylene blue (MB) and crystal violet (CV), and the maximum degradation efficiency was found as 90 and 94%, respectively. Furthermore, the toxicity test on zebrafish embryos demonstrated that aberrations have only been induced at concentrations higher than 500 μg/mL. We conclude that the greenly produced Ag-NPs may find use in biomedical applications based on bacteria and cost-effective industrial wastewater treatment.

Heavy metal co-resistance with antibiotics amongst bacteria isolates from an open dumpsite soil

Heavy metal co-resistance with antibiotics appears to be synergistic in bacterial isolates via similar mechanisms. This synergy has the potential to amplify antibiotics resistance genes in the environment which can be transferred into clinical settings. The aim of this study was to assess the co-resistance of heavy metals with antibiotics in bacteria from dumpsite in addition to physicochemical analysis. Sample collection, physicochemical analysis, and enumeration of total heterotrophic bacteria counts (THBC) were all carried out using standard existing protocols. Identified bacteria isolates were subjected to antibiotics sensitivity test using the Kirby Bauer disc diffusion technique and the resulting multidrug resistant (MDR) isolates were subjected to heavy metal tolerance test using agar dilution technique with increasing concentrations (50, 100, 150, 200 and to 250 μg/ml) of our study heavy metals. THBC ranged from 6.68 to 7.92 × 105 cfu/g. Out of the 20 isolates subjected to antibiotics sensitivity, 50% (n = 10) showed multiple drug resistance and these were B. subtilis, B. cereus, C. freundii, P. aeruginosa, Enterobacter sp, and E. coli (n = 5). At the lowest concentration (50 μg/ml), all the MDR isolates tolerated all the heavy metals, but at 250 μg/ml, apart from cadmium and lead, all test isolates were 100% sensitive to chromium, vanadium and cobalt. The control isolate was only resistant to cobalt and chromium at 50 μg/ml, but sensitive to other heavy metals at all concentrations The level of co-resistance shown by these isolates is a call for concern.

Antagonistic, synergistic, and additive antibacterial interaction between ciprofloxacin and amoxicillin against Staphylococcus aureus

The aim of this in vitro study was to evaluate the interaction between ciprofloxacin and amoxicillin against beta-lactamase-producing Staphylococcus aureus. Concentration-dependent curves for each individual drug were carried out to obtain the mean inhibitory concentration in the agar well diffusion assay. Then, different ratios of the ciprofloxacin-amoxicillin combination (0.5:0.5, 0.8:0.2, 0.2:0.8, 0.9:0.1, 0.1:0.9, 0.95:0.05, and 0.05:0.95) were assessed. Data were analyzed using the isobolographic analysis and interaction index. The isobolographic evaluation shows that the 0.9:0.1 and 0.95:0.05 ratios of the ciprofloxacin-amoxicillin combination produced a synergistic antimicrobial interaction, the 0.8:0.2, 0.2:0.8, 0.1:0.9, and 0.05:0.95 proportions showed an additive antibacterial effect, and the 0.5:0.5 proportion induced antagonistic antimicrobial effects. The interaction index showed similar outcomes to the isobolographic analysis. In conclusion, the data of this study mainly show antimicrobial additive results of the ciprofloxacin-amoxicillin combination against beta-lactamase-producing S. aureus.

Nanotechnology Involved in Treating Urinary Tract Infections: An Overview

Considered as the most frequent contaminations that do not require hospitalization, urinary tract infections (UTIs) are largely known to cause significant personal burdens on patients. Although UTIs overall are highly preventable health issues, the recourse to antibiotics as drug treatments for these infections is a worryingly spread approach that should be addressed and gradually overcome in a contemporary, modernized healthcare system. With a virtually alarming global rise of antibiotic resistance overall, nanotechnologies may prove to be the much-needed 'lifebuoy' that will eventually suppress this prejudicial phenomenon. This review aims to present the most promising, currently known nano-solutions, with glimpses on clinical and epidemiological aspects of the UTIs, prospective diagnostic instruments, and non-antibiotic treatments, all of these engulfed in a comprehensive overview.

Integration of Corn and Cane for Ethanol Production: Effects of Lactobacilli Contamination on Fermentative Parameters and Use of Ionizing Radiation Treatment for Disinfection

Recently, in Brazil, corn ethanol industries are being installed and the integration with sugar/energy-cane has been proposed, using bagasse for cogeneration and the juice to dilute the corn. However, this integration may have some limitations, such as the quality of the cane juice and potential contamination by microorganisms brought with the cane from the field. In this article, we first tested the effects of mixing energy cane juice with corn on fermentative parameters. We also assessed the effects of Lactobacilli. contamination on organic acids produced during the fermentation and fermentation parameters and proposed the use of ionizing radiation to replace antibiotics as a disinfection control method. Our results showed that mixing energy cane juice with corn does not have any negative effect on fermentation parameters, including ethanol production. The contamination with Lactobacilli. considerably increased the production of acetic, lactic, and succinic acid, reducing the pH and ethanol content from 89.2 g L−1 in the sterilized treatment to 72.9 g L−1 in the contaminated treatment. Therefore, for the integration between corn and cane to be applied on an industrial scale, it is essential to have effective disinfection before fermentation. Ionizing radiation (20 kGy) virtually disinfected the wort, showing itself to be a promising technology; however, an economic viability study for adopting it in the industry should be carried out.

Development and Evaluation of the Efficacy and Toxicity of a New Hybrid Antimicrobial Peptide MY8

BACKGROUND

Antibiotics have led to significant advancements in medicine. Unfortunately, they were faced with the emergence of pathogen resistance. According to the World Health Organization, antimicrobial resistance has been declared one of humanity's top ten global public health threats. The risk of those bacteria is not only from their being resistant to multi-antibiotics but also from their ability to form biofilms, which can be 1,000 times more resistant than planktonic bacteria.

METHOD

This study used rational design to hybridize two antimicrobial peptides, aiming to enhance their efficacy and stability with reduced toxicity.

RESULTS

The MY8 novel peptide was designed from the parent peptides BMAP-27 and CAMP 211-225. Some amino acid modifications were introduced to the hybrid peptide to improve its physicochemical properties guided by several software. Its antimicrobial activity has been studied against gram-negative and gram-positive strains, which showed broad-spectrum activity with MIC values against planktonic bacteria ranging from 0.125 to 25 μM. In contrast, 25-200 μM were needed to eradicate biofilms. Moreover, the MY8 peptide showed synergism with four conventional antibiotics., It also showed reduced toxicity against mammalian cells and a slight hemolysis tendency towards erythrocytes.

CONCLUSION

The design of the MY8 peptide was successful, resulting in a novel, potent, broad-spectrum antimicrobial peptide with reduced toxicity and possible synergism with conventional antibiotics.

Emergent crisis of antibiotic resistance: A silent pandemic threat to 21st century

Antibiotic resistance has become an indispensably alarming menace to the global community. The primary factors are overuse and abuse of antibiotics, lack of novel medicines under development, the health care industry's focus on profit, and the absence of diagnostic testing prior to the prescription of antibiotics. Additionally, over the past few decades, the main factors contributing to the global spread of antibiotic resistance have been the overuse of antibiotics in livestock and other animals, drug efficacy, development of fewer new vaccines, environmental toxicity, transmission through travel, and lack of funding for healthcare research and development. These factors have accelerated resistance in microorganisms through structural and functional modifications in bacteria such as reduced drug permeability, increased efflux pumps, enzymatic antibiotic modification, and change in drug target, intracellular infection, and biofilm creation. There has been an increase in resistance during the pandemic and among cancer patients due to improper prescriptions. A number of modern therapeutic alternatives have been developed to curb widespread antibiotic resistance such as nanoparticle, bacteriophage, and antimicrobial biochemical approaches. It is high time to explore new alternatives to curtail enormous increase in resistant pathogens which could be an incurable global confrontation. This review highlights the complete insight on the global drivers of resistance along with the modes of action and impacts, finally discussing the latest therapeutic alternatives.

Serrapeptase impairs biofilm, wall, and phospho-homeostasis of resistant and susceptible Staphylococcus aureus

Staphylococcus aureus biofilms are implicated in hospital infections due to elevated antibiotic and host immune system resistance. Molecular components of cell wall including amyloid proteins, peptidoglycans (PGs), and lipoteichoic acid (LTA) are crucial for biofilm formation and tolerance of methicillin-resistant S. aureus (MRSA). Significance of alkaline phosphatases (ALPs) for biofilm formation has been recorded. Serrapeptase (SPT), a protease of Serratia marcescens, possesses antimicrobial properties similar or superior to those of many antibiotics. In the present study, SPT anti-biofilm activity was demonstrated against S. aureus (ATCC 25923, methicillin-susceptible strain, methicillin-susceptible S. aureus (MSSA)) and MRSA (ST80), with IC₅₀ values of 0.67 μg/mL and 7.70 μg/mL, respectively. SPT affected bacterial viability, causing a maximum inhibition of - 46% and - 27%, respectively. Decreased PGs content at [SPT] ≥ 0.5 μg/mL and ≥ 8 μg/mL was verified for MSSA and MRSA, respectively. In MSSA, LTA levels decreased significantly (up to - 40%) at lower SPT doses but increased at the highest dose of 2 μg/mL, a counter to spectacularly increased cellular and secreted LTA levels in MRSA. SPT also reduced amyloids of both strains. Additionally, intracellular ALP activity decreased in both MSSA and MRSA (up to - 85% and - 89%, respectively), while extracellular activity increased up to + 482% in MSSA and + 267% in MRSA. Altered levels of DING proteins, which are involved in phosphate metabolism, in SPT-treated bacteria, were also demonstrated here, implying impaired phosphorus homeostasis. The differential alterations in the studied molecular aspects underline the differences between MSSA and MRSA and offer new insights in the treatment of resistant bacterial biofilms. KEY POINTS: • SPT inhibits biofilm formation in methicillin-resistant and methicillin-susceptible S. aureus. • SPT treatment decreases bacterial viability, ALP activity, and cell wall composition. • SPT-treated bacteria present altered levels of phosphate-related DING proteins.

Synthesis of AgNPs from leaf extract of Naringi crenulata and evaluation of its antibacterial activity against multidrug resistant bacteria

The biosynthesis of AgNPs using a methanolic extract of Naringi crenulata is described in this study. UV-visible spectroscopy, X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), particle size analyzer (PSA), scanning electron microscope (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM) were used to characterize the synthesized AgNPs. The UV-visible spectrum revealed a sharp peak at 420 nm, which represents silver's strong Plasmon resonance. FTIR and XRD confirmed the functional groups (N-H stretch, alkanes, O-H stretch, carboxylic acid, N-H bend, C-X fluoride, and C-N stretch) and face-centered cubic crystalline structure of synthesized AgNPs. SEM and TEM analyses revealed that the synthesized nanoparticles had a spherical morphology with an average diameter of 32.75 nm. The synthesized AgNPs have antibacterial activity against multidrug-resistant bacteria pathogens such as Vibrio cholerae, Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, and Klebsiella pneumoniae. AgNPs can be synthesized using a methanolic extract of Naringi crenulate, and the resulting particle may have wide range of biological applications.

Antibacterial Activity and Toxicity of Zinc Oxide Nanoparticles Combined with Supernatants of Lactobacillus spp. Against ESKAPE Bacteria: A Novel Mixture

Background

The emergence of multidrug resistance among nosocomial pathogens has prompted researchers to look for new antibacterial sources. Metal nanoparticles and probiotic products have attracted the attention of researchers. However, combination therapy is an attractive alternative in this field.

Objectives

This study evaluated the antibacterial activity and toxicity of Zinc Oxide nanoparticles (ZnO-NPs) combined with cell-free supernatant (CFS) of Lactobacillus plantarum and Lactobacillus acidophilus alone and in a novel mixture.

Methods

Antibacterial effects and cytotoxic properties of ZnO-NPs, CFS of L. plantarum (SLP), and CFS of L. acidophilus (SLA) were determined alone and in a mixture against ESKAPE strains. In addition, the viability percentage of the cells was evaluated after exposure to these agents.

Results

Antibacterial mixtures (ZnO-NPs with SLP or ZnO-NPs with SLA) demonstrated synergistic and additive effects against Pseudomonas aeruginosa (FIC≤0.75), Acinetobacter baumannii (FIC = 1), and Escherichia coli (FIC≤0.75). The viability percentage of the cells after 24 h of exposure to a mixture of ZnO-NPs and SLA (about 50%) was more than when the cells were exposed to ZnO-NPs alone (about 30%) at the same concentration.

Conclusions

A mixture of ZnO-NPs and CFS of probiotics can be an alternative to antibiotics, with more effectiveness and fewer side effects.

The Antimicrobial and Toxicity Influence of Six Carrier Oils on Essential Oil Compounds

Essential oil compounds have been identified as alternative antimicrobials; however, their use is limited due to their toxicity on human lymphocytes, skin, and reproduction. Carrier oils can reduce the toxicity of essential oils, which raises the question as to whether such activity would extend to the essential oil compounds. Thus, this study aimed to investigate the antimicrobial and toxicity activity of essential oil compounds in combination with carrier oils. The antimicrobial properties of the essential oil compounds, alone and in combination with carrier oils, were determined using the broth microdilution assay. The toxicity was determined using the brine shrimp lethality assay. Antimicrobial synergy (ΣFIC ≤ 0.50) occurred in 3% of the samples when tested against the ESKAPE pathogens. The compound thymoquinone in combination with the carrier oil Prunus armeniaca demonstrated broad-spectrum synergistic activity and a selectivity index above four, highlighting this combination as the most favorable. The carrier oils reduced the toxicity of several compounds, with Calendula officinalis and P. armeniaca carrier oils being responsible for the majority of the reduced toxicity observed. This study provides insight into the interactions that may occur when adding a carrier oil to essential oil compounds.

Last Resort Antibiotics Costs and Reimbursement Analysis of Real-Life ICU Patients with Pneumonia Caused by Multidrug-Resistant Gram-Negative Bacteria in Germany

Multidrug-resistant Gram-negative bacteria (MDR-GNB) cause serious infections and aggravate disease progression. Last resort antibiotics are effective against MDR-GNB and are reimbursed by flat rates based on German diagnosis-related groups (G-DRG). From a hospital management perspective, this analysis compared hospital reimbursement for last resort antibiotics with their acquisition costs to outline potential funding gaps. Retrospective analyses based on medical charts and real-life reimbursement data included patients with pneumonia due to MDR-GNB treated in intensive care units (ICU) of a German tertiary care hospital (University Hospital Cologne) between January 2017 and December 2020. Drug-associated hospital reimbursement of G-DRG was compared with drug acquisition costs based on preliminarily approved last resort antibiotics (cefiderocol, ceftazidime-avibactam, ceftolozane-tazobactam, and imipenem-cilastatin-relebactam) according to label. Funding gaps were determined for the treatment of Enterobacterales, Pseudomonas aeruginosa, Acinetobacter baumannii, and mixed infections, respectively. Most of the 31 patients were infected with Enterobacterales (n = 15; 48.4%) and P. aeruginosa (n = 13; 41.9%). Drug-associated G-DRG reimbursement varied from 44.50 EUR (mixed infection of P. aeruginosa and Enterobacterales) to 2265.27 EUR (P. aeruginosa; mixed infection of P. aeruginosa and Enterobacterales). Drug acquisition costs ranged from 3284.40 EUR in ceftazidime-avibactam (minimum duration) to 15,827.01 EUR for imipenem-cilastatin-relebactam (maximum duration). Underfunding was found for all MDR-GNB, reaching from 1019.13 EUR (P. aeruginosa; mixed infection of P. aeruginosa and Enterobacterales) to 14,591.24 EUR (Enterobacterales). This analysis revealed the underfunding of last resort antibiotics in German hospital treatment. Insufficient reimbursement implies less research in this field, leading to a more frequent use of inappropriate antibiotics. The cycle closes as this contributes to the development of multi-drug resistant bacteria.

Additive Nanosecond Laser-Induced Forward Transfer of High Antibacterial Metal Nanoparticle Dose onto Foodborne Bacterial Biofilms

Additive laser-induced forward transfer (LIFT) of metal bactericidal nanoparticles from a polymer substrate directly onto food bacterial biofilms has demonstrated its unprecedented efficiency in combating pathogenic microorganisms. Here, a comprehensive study of laser fluence, metal (gold, silver and copper) film thickness, and the transfer distance effects on the antibacterial activity regarding biofilms of Gram-negative and Gram-positive food bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Listeria monocytogenes, Salmonella spp.) indicated the optimal operation regimes of the versatile modality. LIFT-induced nanoparticle penetration into a biofilm was studied by energy-dispersion X-ray spectroscopy, which demonstrated that nanoparticles remained predominantly on the surface of the biofilm.

Impact of antimicrobial stewardship on antibiogram, consumption and incidence of multi drug resistance

INTRODUCTION

Antimicrobial stewardship programs are intended to improve patient outcomes, reduce side effects, bacterial resistance, and costs. Thus, it is important to assess their impact on an ongoing basis. We aimed to assess the impact of the antimicrobial stewardship program in two different hospitals which used different program approaches.

METHODOLOGY

This is a retrospective observational study in two private hospitals [4088 patient records] in Amman- Jordan. Antibiotic susceptibility using antibiogram results, consumption of antibiotics using Defined Daily Dose, and the incidence of Multi-Drug Resistance were recorded using patients' records during 2018, 2019, and 2020.

RESULTS

Antimicrobial stewardship program outcomes varied between the two hospitals. Bacterial susceptibility to antibiotics were improved in both hospitals. Moreover, the defined daily dose in Hospital "A" showed no significant change in Fluoroquinolones, Carbapenems, and Piperacillin- Tazobactam, Cephalosporins, and Colistin, while a significant change was observed among Anti-MRSA antibiotics. Finally, the incidence of Extended Spectrum Beta-lactamase [ESBL] E. coli, ESBL Klebsiella, and Vancomycin Resistant Enterococci [VRE] have decreased numerically over the study period, while Methicillin-Resistant Staphylococcus aureus [MRSA] showed an increase in incidence during the second year of the study.

CONCLUSION

The study emphasizes the positive impact of the AMS program throughout the three years of the study. Plus, the need to enhance the program through recruiting extra staff and applying extra regulations like implementing educational programs for the hospital staff, designing local guidelines for common ID diseases, and monitoring the program's outcomes which would eventually be more efficient, cost-effective, and safe.

Recent advances in bacteriophage-based therapeutics: Insight into the post-antibiotic era

Antibiotic resistance is one of the biggest threats to global health, as it can make the treatment of bacterial infections in humans difficult owing to their high incidence rate, mortality, and treatment costs. Bacteriophage, which constitutes a type of virus that can kill bacteria, is a promising alternative strategy against antibiotic-resistant bacterial infections. Although bacteriophage therapy was first used nearly a century ago, its development came to a standstill after introducing the antibiotics. Nowadays, with the rise in antibiotic resistance, bacteriophage therapy is in the spotlight again. As bacteriophage therapy is safe and has significant anti-bacterial activity, some specific types of bacteriophages (such as bacteriophage phiX174 and Pyo bacteriophage complex liquid) entered into phase III clinical trials. Herein, we review the key points of the antibiotic resistance crisis and illustrate the factors that support the renewal of bacteriophage applications. By summarizing recent state-of-the-art studies and clinical data on bacteriophage treatment, we introduced (i) the pharmacological mechanisms and advantages of antibacterial bacteriophages, (ii) bacteriophage preparations with clinical potential and bacteriophage-derived anti-bacterial treatment strategies, and (iii) bacteriophage therapeutics aimed at multiple infection types and infection-induced cancer treatments. Finally, we highlighted the challenges and critical perspectives of bacteriophage therapy for future clinical development.

Droplet Microarray as a Powerful Platform for Seeking New Antibiotics Against Multidrug-Resistant Bacteria

Multidrug-resistant (MDR) bacteria is a severe threat to public health. Therefore, it is urgent to establish effective screening systems for identifying novel antibacterial compounds. In this study, a highly miniaturized droplet microarray (DMA) based high-throughput screening system is established to screen over 2000 compounds for their antimicrobial properties against carbapenem-resistant Klebsiella pneumoniae and methicillin resistant Staphylococcus aureus (MRSA). The DMA consists of an array of hydrophilic spots divided by superhydrophobic borders. Due to the differences in the surface wettability between the spots and the borders, arrays of hundreds of nanoliter-sized droplets containing bacteria and different drugs can be generated for screening applications. A simple colorimetric viability readout utilizing a conventional photo scanner is developed for fast single-step detection of the inhibitory effect of the compounds on bacterial growth on the whole array. Six hit compounds, including coumarins and structurally simplified estrogen analogs are identified in the primary screening and validated with minimum inhibition concentration assay for their antibacterial effect. This study demonstrates that the DMA-based high-throughput screening system enables the identification of potential antibiotics from novel synthetic compound libraries, offering opportunities for development of new treatments against multidrug-resistant bacteria.

Photophysical and in vitro photoinactivation of Escherichia coli using cationic 5,10,15,20-tetra(pyridin-3-yl) porphyrin and Zn(II) derivative conjugated to graphene quantum dots

Pathogenic microorganisms may continue causing infection through the transfer of antibiotic resistance genes. As a result, the efficacy of pharmaceuticals in microbial inactivation is deteriorating. The present study was conducted to investigate the antimicrobial activity of neutral and quaternized free base and Zn 5,10,15,20-tetra(pyridin-3-yl) porphyrins on Escherichia coli (E. coli), a gram-negative bacterium that causes cholecystitis, pneumonia and urinary tract infections. Conjugation of the porphyrin to graphene quantum dots (GQDs) was implemented to enhance photocatalysis and reactive oxygen species generation. Density functional theory (DFT) geometry optimizations for free base and Zn porphyrin based on the B3LYP (Becke 3-Parameter (Exchange), Lee, Yang and Parr) functional of the Gaussian09 program package and Time-dependent density-functional theory (TD-DFT) calculations of the associated UV-visible absorption spectra are reported to analyse the electronic structure and optical properties of the porphyrins. The TD-DFT calculations showed that for both porphyrins the value of highest occupied molecular orbital (ΔHOMO) is greater than that of lowest unoccupied molecular orbital (ΔLUMO) which tells that there is no unusual splitting of (LUMO) orbitals which may be caused by systematic error in TD-DFT calculations. Due to the red shift in the spectrum of ZnT(3-Py)P and the ΔLUMO being higher, the HOMO-LUMO gap was expected to be lower than that of H₂T(3-Py)P. The photophysical properties and Photodynamic antimicrobial chemotherapy activities of these nanoconjugates were investigated. The highest Φ_Δ was that of Q-ZnT(3-Py)P- GDQs at 0.69 with the log reduction of 9.42.

Prevalence of metallo-β-lactamases as a correlate of multidrug resistance among clinical Pseudomonas aeruginosa isolates in Nepal

Pseudomonas aeruginosa is an opportunistic human pathogen that has developed antibiotic resistance (AR) and causes a range of illnesses, including respiratory pneumonia, gastrointestinal infections, keratitis, otitis media and bacteremia in patients with compromised immune system. The production of metallo-β-lactamases (MBLs) is one of the major mechanisms of AR in this bacterium with ensuing infections difficult to treat. The main goal of this study was to provide a quantitative estimate of MBLs producing clinical P. aeruginosa isolates among the Nepalese patients and determine if MBL correlates with multi-drug resistance (MDR). Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline was followed for meta-analysis of relevant literature using PubMed, Research4Life, and Google Scholar. The prevalence of MBLs in P. aeruginosa from clinical samples was determined using R 4.1.2 for data pooled from studies published until 2021. The meta-analysis of a total of 19 studies selected (of 6038 studies for which titles and abstracts were reviewed) revealed the prevalence of MBLs producing P. aeruginosa (MBL-PA) was 14 % (95 % CI: 0.10-0.19) while MDR isolates among P. aeruginosa was 42 % (95 % CI: 0.30-0.55) in Nepal. Combined Disc Test was predominantly used phenotypic method for confirming MBLs phenotypes among the studies. Sputum was the most common specimen from which MBL-PA was recovered. A significant positive correlation was observed between MDR and MBL production in P. aeruginosa. We conclude that MBL producing strains are widespread among the clinical isolates of P. aeruginosa in Nepal and responsible for emerging MDR strains. It is paramount that antibiotics prescription against the bacterium should be monitored closely and alternative therapeutic modalities against MBL-PA explored.

Silver Carboxylate-Eluting Titanium-Dioxide Polydimethylsiloxane Coating Inhibits Multi-Drug-Resistant Acinetobacterium baumannii and Vancomycin-Resistant Enterococcus faecalis Adherence and Proliferation on Orthopedic Trauma Fixation and Spinal Fusion Materials

Background: Vancomycin-resistant Enterococcus faecalis and multi-drug-resistant (MDR) Acinetobacter baumannii are rising contributors to spinal fusion and fracture-associated infections (FAI), respectively. These MDR bacteria can form protective biofilms, complicating traditional antibiotic treatment. This study explores the effects of the antibiotic-independent antimicrobial silver carboxylate (AgCar)-doped coating on the adherence sand proliferation of these pathogens on orthopedic implant materials utilized in spinal fusion and orthopedic trauma fixation. Methods: Multi-drug-resistant Acinetobacter baumannii and vancomycin-resistant Enterococcus faecalis were inoculated on five common implant materials: cobalt chromium, titanium, titanium alloy, polyether ether ketone, and stainless steel. Dose response curves were generated to assess antimicrobial potency. Scanning electron microscopy and confocal laser scanning microscopy were utilized to characterize and quantify growth and adherence on each material. Results: The optimal AgCar concentration was a 95% titanium dioxide (TiO₂)-5% polydimethylsiloxane (PDMS) matrix combined with 10 × silver carboxylate, which inhibited bacterial proliferation by 89.40% (p = 0.001) for MDR Acinetobacter baumannii and 84.02% (p = 0.001) for vancomycin-resistant Enterococcus faecalis compared with uncoated implants. A 95% TiO₂-5% PDMS matrix combined with 10 × AgCar was equally effective at inhibiting bacterial proliferation across all implant materials for MDR Acinetobacter baumannii (p = 0.19) and vancomycin-resistant Enterococcus faecalis (p = 0.07). A 95% TiO2-5% PDMS matrix with 10 × AgCar is effective at decreasing bacterial adherence of both MDR Acinetobacter baumannii and vancomycin-resistant Enterococcus faecalis on implant materials. Conclusions: Application of this antibiotic-independent coating for surgery in which these implant materials might be used may prevent adherence, biofilm formation, spinal infections, and FAI by MDR Acinetobacter baumannii and vancomycin-resistant Enterococcus faecalis.

Cationic Surfactants Based on Arginine-Phenylalanine and Arginine-Tryptophan: Synthesis, Aggregation Behavior, Antimicrobial Activity, and Biodegradation

Cationic surfactants have great potential as drug vehicles and for use in gene therapy (cationic vesicles made from cationic surfactants can encapsulate RNA or DNA for cellular transfer). They can also be used as antimicrobial and antifungal agents to treat human infections. In an era of increasing antimicrobial resistance, the development of new biocompatible surfactants suitable for application as antimicrobial agents is of high interest. In this work, a library of amino acid-based surfactants was synthesized, characterized and tested for antimicrobial activity. The head group architecture (number and type of amino acids, density of cationic charge, ionic character) and the hydrophobic moiety (alkyl chain length and position of the hydrophobic group) were systematically modified, and the effect on the surfactant biological and aggregation behavior was studied. Thus, the pKa values, micellization process, antimicrobial efficiency and biodegradability were evaluated. The critical micelle concentration values of the surfactants depended on their hydrophobic character, but changes in the polar head as well as the position and length of the alkyl chain also significantly affected activity against some of the tested microorganisms. Moreover, biodegradability was closely related to the hydrophobic character of the surfactant and attachment of the alkyl chain to the polar head. The structure-activity relationships established here may open perspectives for the design of effective biodegradable antimicrobial materials that can overcome emerging resistance.

Synthesis, in silico studies and biological screening of (E)-2-(3-(substitutedstyryl)-5-(substitutedphenyl)-4,5-dihydropyrazol-1-yl)benzo[d]thiazole derivatives as an anti-oxidant, anti-inflammatory and antimicrobial agents

A new series of (E)-2-(3-(substitutedstyryl)-5-(substitutedphenyl)-4,5-dihydropyrazol-1-yl)benzo[d]thiazole derivatives was synthesized and the chemical structures of synthesized compounds were deduced by IR and NMR spectral tools. These compounds were synthesized via aldol condensation reaction of substituted benzaldehydes and acetone in alkaline ethanolic solution and their in vitro anti-oxidant, anti-inflammatory and antimicrobial activities were investigated. All the synthesized compounds displayed anti-oxidant potential with IC₅₀ values ranging from 0.13 to 8.43 µmol/ml. The compound Z13 exhibited potent anti-inflammatory activity with IC₅₀ value of 0.03 µmol/ml compared with the standard ibuprofen, which showed IC₅₀ value of 0.11 µmol/ml. On the other hand, most of the compounds had a certain antibacterial potential particularly against P. aeruginosa and among these derivatives, compound Z2 exhibited the highest potential against P. aeruginosa with MIC value of 0.0069 µmol/ml. The analysis of docking results demonstrated the binding affinity and hydrogen bond, electrostatic and hydrophobic interactions of all the synthesized compounds with their respective targets. In silico ADMET studies were carried out for the synthesized compounds and most of the compounds exhibited good ADMET profile.

The Effects of Ventilation, Humidity, and Temperature on Bacterial Growth and Bacterial Genera Distribution

BACKGROUND

Bacteria are readily nourished in airtight environments with high humidity, such as storage cabinets, clothing closets, and corners, where ventilation is normally low and humidity is high.

OBJECTIVES

We characterized the role of humidity and ventilation in bacterial growth and genus distribution at different temperatures (26 °C and 34 °C).

METHODS

Fresh pork, which was used as the substrate for bacterial culture, was placed in storage cabinets. Bacterial growth and genera distribution on the surface of pork placed in a storage cabinet under different temperatures (26 °C and 34 °C); relative humidity levels (RH: 50%, 70%, 90%); and ventilation conditions (no ventilation and low, medium, and high levels of ventilation) were assessed by rDNA sequencing.

RESULTS

Increased ventilation and reduced humidity significantly decreased bacterial growth at 26 °C and 34 °C. The contribution of increased ventilation to the reduction in bacterial growth exceeded that of decreased humidity. Ventilation had the greatest effect on reducing bacterial growth compared to the unventilated conditions at 70% RH. At 34 °C, medium and high levels of ventilation were required to reduce bacterial growth. High temperatures greatly increased bacterial growth, but ventilation could reduce the degree of this increase.

Anti-infective therapy using species-specific activators of Staphylococcus aureus ClpP

The emergence of methicillin-resistant Staphylococcus aureus isolates highlights the urgent need to develop more antibiotics. ClpP is a highly conserved protease regulated by ATPases in bacteria and in mitochondria. Aberrant activation of  bacterial ClpP is an alternative method of discovering antibiotics, while it remains difficult to develop selective  Staphylococcus aureus ClpP activators that can avoid disturbing Homo sapiens ClpP functions. Here, we use a structure-based design to identify (R)- and (S)-ZG197 as highly selective Staphylococcus aureus ClpP activators. The key structural elements in Homo sapiens ClpP, particularly W146 and its joint action with the C-terminal motif, significantly contribute to the discrimination of the activators. Our selective activators display wide antibiotic properties towards an array of multidrug-resistant staphylococcal strains in vitro, and demonstrate promising antibiotic efficacy in zebrafish and murine skin infection models. Our findings indicate that the species-specific activators of Staphylococcus aureus ClpP are exciting therapeutic agents to treat staphylococcal infections.

Effect of the pH on the Antibacterial Potential and Cytotoxicity of Different Plasma-Activated Liquids

In this study, different plasma-activated liquids were evaluated for their antimicrobial effects against Escherichia coli, as well as for their cytotoxicity on mammalian cells. The PALs were prepared from distilled (DIS), deionized (DI), filtered (FIL), and tap (TAP) water. Additionally, 0.9% NaCl saline solution (SAL) was plasma-activated. These PALs were prepared using 5 L/min air gliding arc plasma jet for up to 60.0 min of exposure. Subsequently, the physicochemical properties, such as, the oxidation-reduction potential (ORP), the pH, the conductivity, and the total dissolved solids (TDS) were characterized by a water multiparameter. The PALs obtained showed a drastic decrease in the pH with increasing plasma exposure time, in contrast, the conductivity and TDS increased. In a general trend, the UV-vis analyses identified a higher production of the following reactive species of nitrogen and oxygen (RONS), HNO₂, H₂O₂, NO₃^-, and NO₂^-. Except for the plasma-activated filtered water (PAW-FIL), where there was a change in the position of NO₂^- and NO₃^- at some pHs, The higher production of HNO₂ and H₂O₂-reactive species was observed at a low pH. Finally, the standardized suspensions of Escherichia coli were exposed to PAL for up to 60.0 min. The plasma-activated deionized water (PAW-DI pH 2.5), plasma-activated distilled water (PAW-DIS pH 2.5 and 3), and plasma-activated tap water (PAW-TAP 3.5) showed the best antimicrobial effects at exposure times of 3.0, 10.0, and 30.0 min, respectively. The MTT analysis demonstrated low toxicity of all of the PAL samples. Our results indicate that the plasma activation of different liquids using the gliding arc system can generate specific physicochemical conditions that produce excellent antibacterial effects for E. coli with a safe application, thus bringing future contributions to creating new antimicrobial protocols.

Ultrasensitive detection of β-lactamase-associated drug-resistant bacteria using a novel mass-tagged probe-mediated cascaded signal amplification strategy

The emergence and spread of drug-resistant bacteria (DRB) is a global health threat. Early and accurate detection of DRB is a critical step in the treatment of DRB infection. However, traditional assays for DRB detection are time-consuming and have inferior analytical sensitivity and quantification capability. Herein, a mass-tagged probe (MP-CMSA)-mediated enzyme- and light-assisted cascaded signal amplification strategy was developed for the ultrasensitive detection of β-lactamase (BLA), an enzyme closely associated with most DRB. Each MP-CMSA probe contained multiple poly(amidoamine) (PAMAM) dendrimer molecules immobilized on a streptavidin agarose bead via a BLA-cleavable linker, and each dendrimer was modified with multiple mass tags via a photo-cleavable linker. In BLA detection, BLA could cleave the BLA-cleavable linker, leading to dendrimers shedding from the MP-CMSA probe to achieve enzyme-assisted signal amplification. Then, each dendrimer can further release mass tags under UV light to achieve light-assisted signal amplification. After this cascaded signal amplification, the released mass tags were ultimately quantified by mass spectrometry. Consequently, the sensitivity of BLA detection can be significantly enhanced by four orders of magnitude with a detection limit of 50.0 fM. Finally, this approach was applied to the blood samples from patients with DRB. This platform provides a potential strategy for the sensitive, rapid and quantitative detection of DRB infection.

Characterisation and antibiotic resistance of Yersinia enterocolitica from various meat categories, South Africa

Yersinia enterocolitica infections impose a significant public health and socioeconomic burden on human population in many countries. The current study investigated the prevalence, antimicrobial resistance profile and molecular diversity of Y. enterocolitica in meat and meat products across various retail outlets in selected provinces of South Africa (SA). In a cross-sectional study, a total of 581 retail meat and meat products were collected from four cities across three provinces of SA. Samples were from beef and pork products, which included 292 raw intact, 167 raw processed, and 122 ready-to-eat (RTE) meats. Samples were analysed using classical microbiological methods for isolation, identification and biotyping of Y. enterocolitica. Conventional polymerase chain reaction (PCR) was performed for confirmation, serotyping, screening of virulence (n = 11) and antimicrobial resistance (n = 18) genes. Phenotypic antimicrobial resistance profiles were determined against 12 antibiotics discs, using disc diffusion method. The overall prevalence of 12% (70/581) was reported across all cities with contamination proportion reported in samples collected from raw intact 15% (43/292), followed by raw processed 11% (18/167) and RTE meats 7% (9/122). All positive isolates were of biotype 1A with 7% (5/70) belonging to bioserotype 1A/O:8. Most of the isolates harboured ymoA, ystB, fepD, ail, fepA, invA and myfA virulence genes. High antimicrobial resistance frequency was observed for ampicillin (94%), cephalothin (83%) and amoxicillin (41%), respectively. Of the 18 tested antimicrobial resistance genes, blaTEM was the most predominant (40%) followed by cmlA (21%). This study reveals the presence of antimicrobial resistant Y. enterocolitica possessing virulent genes of public health importance in products of animal origin, therefore, health monitoring and surveillance of this pathogen is required.

Multiplex immunochromatographic platform based on crystal violet tag for simultaneous detection of streptomycin and chloramphenicol

Antibiotic abuse has caused serious health risks for human beings for long. To address the problem, novel and facile detection techniques are highly desired. Here, an effective multiplex immunochromatographic platform (MICP) with synthesis-free and cost-effective merits is established for simultaneous detection of antibiotics on a single immunochromatographic assay (ICA) strip. Adopting crystal violet (CV) as a signal tag for multiplex ICA allows for direct coupling with multiple antibodies in several minutes. By combining CV and ICA perfectly, this convenient strategy offers improvements in convenience, speed, flexibility, and portability, eventually ensuring the optimized effectiveness of this approach. As a result, the established platform is successfully used to detect streptomycin (STR) and chloramphenicol (CAP) with visual detection mode, and the obtained total recoveries of milk and honey real samples changed from 83.82 to 113.38% with total RSD values of 0.48 to 4.15%.

Synthesis and biological evaluation of novel N, N'-diarylurea derivatives as potent antibacterial agents against MRSA

A series of new N, N'-diarylurea derivatives were designed and synthesized, some of which exhibited potent antibacterial activity against the drug-susceptible and drug-resistant Gram-positive strains. Especially, compounds 2c, 2g-2l showed broader antibacterial spectrum and more potent antibacterial activity (MIC = 0.30-2.72 μM) against MRSA and MRSE than the control levofloxacin (MIC = 0.69-22.14 μM). In addition, compounds 2c, 2g, 2h and 2l exhibited much better antibacterial activity (MIC = 1.29-2.86 μM) against VRE (E. faecium) than sorafenib (MIC = 275.37 μM), PK150 (MIC = 5.07-10.13 μM) and SC78 (MIC = 2.40-4.79 μM). More importantly, the low cytotoxicity of compounds on cell lines HeLa and HepG2 implied a relatively wide therapeutic window, which was of high importance for further study.

Advances of Cobalt Nanomaterials as Anti-Infection Agents, Drug Carriers, and Immunomodulators for Potential Infectious Disease Treatment

Infectious diseases remain the most serious public health issue, which requires the development of more effective strategies for infectious control. As a kind of ultra-trace element, cobalt is essential to the metabolism of different organisms. In recent decades, nanotechnology has attracted increasing attention worldwide due to its wide application in different areas, including medicine. Based on the important biological roles of cobalt, cobalt nanomaterials have recently been widely developed for their attractive biomedical applications. With advantages such as low costs in preparation, hypotoxicity, photothermal conversion abilities, and high drug loading ability, cobalt nanomaterials have been proven to show promising potential in anticancer and anti-infection treatment. In this review, we summarize the characters of cobalt nanomaterials, followed by the advances in their biological functions and mechanisms. More importantly, we emphatically discuss the potential of cobalt nanomaterials as anti-infectious agents, drug carriers, and immunomodulators for anti-infection treatments, which might be helpful to facilitate progress in future research of anti-infection therapy.

Evaluation and Validation of the Limited Sampling Strategy of Polymyxin B in Patients with Multidrug-Resistant Gram-Negative Infection

Polymyxin B (PMB) is the final option for treating multidrug-resistant Gram-negative bacterial infections. The acceptable pharmacokinetic/pharmacodynamic target is an area under the concentration–time curve across 24 h at a steady state (AUC_ss,24h) of 50–100 mg·h/L. The limited sampling strategy (LSS) is useful for predicting AUC values. However, establishing an LSS is a time-consuming process requiring a relatively dense sampling of patients. Further, given the variability among different centers, the predictability of LSSs is frequently questioned when it is extrapolated to other clinical centers. Currently, limited data are available on a reliable PMB LSS for estimating AUC_ss,24h. This study assessed and validated the practicability of LSSs established in the literature based on data from our center to provide reliable and ready-made PMB LSSs for laboratories performing therapeutic drug monitoring (TDM) of PMB. The influence of infusion and sampling time errors on predictability was also explored to obtain the optimal time points for routine PMB TDM. Using multiple regression analysis, PMB LSSs were generated from a model group of 20 patients. A validation group (10 patients) was used to validate the established LSSs. PMB LSSs from two published studies were validated using a dataset of 30 patients from our center. A population pharmacokinetic model was established to simulate the individual plasma concentration profiles for each infusion and sampling time error regimen. Pharmacokinetic data obtained from the 30 patients were fitted to a two-compartment model. Infusion and sampling time errors observed in real-world clinical practice could considerably affect the predictability of PMB LSSs. Moreover, we identified specific LSSs to be superior in predicting PMB AUC_ss,24h based on different infusion times. We also discovered that sampling time error should be controlled within −10 to 15 min to obtain better predictability. The present study provides validated PMB LSSs that can more accurately predict PMB AUC_ss,24h in routine clinical practice, facilitating PMB TDM in other laboratories and pharmacokinetics/pharmacodynamics-based clinical studies in the future.

Synthesis of Trimetallic (Ni-Cu)@Ag Core@Shell Nanoparticles without Stabilizing Materials for Antibacterial Applications

We report a simple method to prepare colloidal trimetallic (Ni-Cu)@Ag core@shell nanoparticles (NPs) without stabilizing materials. Experimental evidence was found for the successful synthesis of these NPs using X-ray diffraction (XRD), optical spectroscopy, and high-resolution transmission electron microscopy (HRTEM). The presence of core metals (Ni and Cu) was confirmed by elemental analysis using a total reflection X-ray fluorescence (TXRF) analysis. In addition, the absorption spectra of the prepared samples exhibited broad bands compared to the bands of the monometallic NPs, indicating the formation of a core-shell nanostructure. The antibacterial activity of the trimetallic NPs was evaluated against three Gram-negative (Pseudomonas aeruginosa, Escherichia coli, and Salmonella) and two Gram-positive (Streptococcus and Staphylococcus aureus) bacteria on Mueller-Hinton agar. These NPs showed high inhibition of bacterial growth at the low sample concentrations used in this study compared to other nanomaterials. One of the interesting results of the current study is that the inhibition zone of Pseudomonas aeruginosa as a resistant bacterium was high for most NPs. These results make the prepared samples promising candidates for antibiotic material applications.

Quinoline-imidazole/benzimidazole derivatives as dual-/multi-targeting hybrids inhibitors with anticancer and antimicrobial activity

Two new classes of hybrid quinoline-imidazole/benzimidazole derivatives (the hybrid QIBS salts and QIBC cycloadducts) were designed and synthesized to evaluate their anticancer and antimicrobial activity. The strategy adopted for synthesis is straight and efficient, in four steps: N-acylation, N-alkylation, quaternization and a Huisgen 3 + 2 cycloaddition. The in vitro single-dose anticancer assay of forty six hybrid quinoline-benzimidazole compounds reveal that one QIBS salt (11h), has an excellent quasi nonselective activity against all type of cancer cell with an excellent PGI in the area of 90-100% and very good lethality. Three others quinoline-imidazole/benzimidazole hybrids (8h, 12h, 12f) has an excellent selective activity against some cancer cell lines: breast cancer MDA-MB-468 and Leukemia HL-60 TB). The five-dose assay screening confirms that compound 11h possesses excellent anti-proliferative activity, with GI₅₀ in the range of nano-molar, against some cancer cell lines: Leukemia HL-60 TB, Leukemia K-526, Leukemia RPMI-8226, Breast cancer MDA-MB-468, Lung cancer HOP-92 and Ovarian cancer IGROV1. The antibacterial assay indicates that three hybrid QIBS salts (12f, 12c, 12d) have an excellent activity against Gram-negative bacteria E. coli (superior to control Gentamicin) while against Gram-positive bacteria S. aureus only one compound 8i (R₂ = -CF3) exhibits a significant activity (superior to control Gentamicin). The MIC assay indicates that two other compounds (11h, 12h) are biologically active to a very low concentration, in the range of nano-molar. We believe that all these excellent assets related to anticancer and antibacterial activities, make from our hybrid quinoline-imidazole/benzimidazole compounds bearing a phenyl group (R₂ = -C₆H₅) in the para (4)-position of the benzoyl moiety a good candidate for future drug developing.