Gram-positive Research Articles

Influence of Nisin Grafting on the Antibacterial Efficacy of AMP Self-Assembled Monolayers (SAMs).

The use of antimicrobial peptides (AMPs) covalently grafted on surfaces has been recognized in recent years as a promising strategy to fight against biofilm formation. However, after grafting, the understanding of AMP-bacteria interactions is still debated in the literature. In this study, Nisin, a cyclic AMP, was grafted onto gold surfaces via an indirect grafting on acidic thiol self-assembled monolayers using succinimide linkers. The physical and chemical properties of these SAMs were then finely characterized by XPS and FT-IR to confirm the covalent grafting of Nisin. The antiadhesion and bactericidal effects were then studied for Escherichia coli ATCC25922, Staphylococcus aureus ATCC 25923, and Listeria ivanovii Li4(pVS2) by a posteriori analysis of the culture supernatants (i.e., indirect technique) and ex situ by optical microscopy following crystal violet staining (i.e., direct technique). Statistical analysis reveals that the Nisin coating has bactericidal and antiadhesive properties towards Gram-positive bacteria, while no significant results were obtained for Gram-negative bacteria.

Antibacterial Mechanisms and Clinical Impact of Sitafloxacin.

Sitafloxacin is a 4th generation fluoroquinolone antibiotic with broad activity against a wide range of Gram-negative and Gram-positive bacteria. It is approved in Japan and used to treat pneumonia and urinary tract infections (UTIs) as well as other upper and lower respiratory infections, genitourinary infections, oral infections and otitis media. Compared to other fluoroquinolones, sitafloxacin displays a low minimal inhibitory concentration (MIC) for many bacterial species but also activity against anaerobes, intracellular bacteria, and persisters. Furthermore, it has also shown strong activity against biofilms of P. aeruginosa and S. aureus in vitro, which was recently validated in vivo with murine models of S. aureus implant-associated bone infection. Although limited in scale at present, the published literature supports the further evaluation of sitafloxacin in implant-related infections and other biofilm-related infections. The aim of this review is to summarize the chemical-positioning-based mechanisms, activity, resistance profile, and future clinical potential of sitafloxacin.

Phage-Derived Endolysins Against Resistant Staphylococcus spp.: A Review of Features, Antibacterial Activities, and Recent Applications.

Antimicrobial resistance is a significant global public health issue, and the dissemination of antibiotic resistance in Gram-positive bacterial pathogens has significantly increased morbidity, mortality rates, and healthcare costs. Among them, Staphylococcus, especially methicillin-resistant Staphylococcus aureus (MRSA), causes a wide range of diseases due to its diverse pathogenic factors and infection strategies. These bacteria also present significant issues in veterinary medicine and food safety. Effectively managing staphylococci-related problems necessitates a concerted effort to implement preventive measures, rapidly detect the pathogen, and develop new and safe antimicrobial therapies. In recent years, there has been growing interest in using endolysins to combat bacterial infections. These enzymes, which are also referred to as lysins, are a unique class of hydrolytic enzymes synthesized by double-stranded DNA bacteriophages. They possess glycosidase, lytic transglycosylase, amidase, and endopeptidase activities, effectively destroying the peptidoglycan layer and resulting in bacterial lysis. This unique property makes endolysins powerful antimicrobial agents, particularly against Gram-positive organisms with more accessible peptidoglycan layers. Therefore, considering the potential benefits of endolysins compared to conventional antibiotics, we have endeavored to gather and review the characteristics and uses of endolysins derived from staphylococcal bacteriophages, as well as their antibacterial effectiveness against Staphylococcus spp. based on conducted experiments and trials.

Studies Regarding Antimicrobial Properties of Some Microbial Polyketides Derived from Monascus Strains.

Finding new molecules to prevent the growth of antimicrobial resistance is a hot topic for scientists worldwide. It has been reported that some raw bioproducts containing Monascus polyketides have antimicrobial activities, but extensive studies on this effect have not been conducted. In this context, our studies aimed to evaluate the antimicrobial properties of six raw bioproducts containing three classes of microbial polyketides biosynthesized by three Monascus strains through solid-state biosynthesis. As a methodology, we performed in silico predictions using programs such as PyMOL v3.0.4 and employed ESI-MS techniques to provide evidence of the presence of the six studied compounds in our bioproducts. The results obtained in silico were validated through in vitro studies using the Kirby-Bauer diffusion method on bacteria and fungi. The test performed in silico showed that Monascorubramine has the highest affinity for both Gram-positive and Gram-negative bacteria, followed by yellow polyketides such as Ankaflavin and Monascin. The estimated pharmacokinetic parameters indicated high gastrointestinal absorption and the potential to cross the blood-brain barrier for all studied compounds. However, the compounds also inhibit most enzymes involved in drug metabolism, presenting some level of toxicity. The best in vitro results were obtained for S. aureus, with an extract containing yellow Monascus polyketides. Predictions made for E. coli were validated in vitro for P. aeruginosa, S. enterica, and S. marcescens, as well as for fungi. Significant antibacterial properties were observed during this study for C. albicans, S. aureus, and fungal dermatophytes for crude bioproducts containing Monascus polyketides. In conclusion, the antimicrobial properties of Monascus polyketides were validated both in silico and in vitro. However, due to their potential toxicity, these bioproducts would be safer to use as topical formulations.

Isolation of Bacillus Velezensis from Leepuram Sea Sediment and Its Bioactive Compound and Antimicrobial Activity

Research into marine bacteria in India for their potential active chemicals is essential for the creation of medications derived from marine sources. The objective of this research was to collect Bacillus velezensis from Leepuram Sea Sediment, test their antibacterial efficacy with the agar diffusion method, and find secondary metabolites by GC-MS spectroscopy.Traditional microbiological methods and phylogenetic analysis of 16S rRNA sequences were used to successfully identify Bacillus velezensis from sediment samples obtained in the Leepuram Sea, Kanyakumari. Using the agar well diffusion method, we tested the isolated metabolites for their antibacterial activity against Gram-positive and Gram-negative bacteria. The results showed that the extract had a strong antibacterial effect, inhibiting the growth of harmful bacteria with zones of inhibition as large as 19 mm for E. coli and Pseudomonas.Bacillus velezensis produces secondary metabolites with pharmacological potential, according to this study. These metabolites may have useful uses in biocontrol, agriculture, and medicine. The implications of these results for human health and the creation of new antimicrobial drugs are likely to grow substantially when more worldwide research is carried out.

Amino acid variability at W194 of Staphylococcus aureus sortase A alters nucleophile specificity.

Bacterial sortases are a family of cysteine transpeptidases in Gram-positive bacteria of which sortase A (SrtA) enzymes are responsible for ligating proteins to the peptidoglycan layer of the cell surface. Engineered versions of sortases are also used in sortase-mediated ligation (SML) strategies for a variety of protein engineering applications. Although a versatile tool, substrate recognition by Staphylococcus aureus SrtA (saSrtA), the most commonly utilized enzyme in SML, is stringent and relies on an LPXTG pentapeptide motif. Previous structural studies revealed that the requirement of a glycine in the binding motif may be due to potential steric hindrance of amino acids possessing a β-carbon by W194, a tryptophan located in the β7-β8 loop of the enzyme. Here, we measured the effect of seven single point mutants of W194 (A, D, F, G, N, S, Y) saSrtA using a FRET-based activity assay. We found that while the LPXTG motif remains a requirement for initial proteolytic cleavage, the nucleophile specificity of our variants is altered. In particular, W194A and W194S saSrtA recognize a D-Ala nucleophile and are able to perform ligation reactions. Notably, an LPXT(D-Ala) peptide was not cleaved by either mutant enzyme. We hypothesize that these variants may potentially be utilized to develop an irreversible sortase-mediated reaction. Taken together, this experiment reveals new insight into sortase specificity and possible future SML strategies.

Intraventricular antibiotics for severe central nervous system infections: a case series

Severe central nervous system infections (CNSI), including community-acquired CNSI (CA-CNSI) and healthcare-associated ventriculitis and meningitis (HAVM), present high morbidity and mortality. Intraventricular antibiotic treatment (IVT) is advisable for these infections, though evidence is limited. We retrospectively analyzed data on 27 patients who received IVT for severe CA-CNSI and HAVM over 10 years, assessing clinical and paraclinical features, such as baseline severity and functional outcome, antibiotics, microbiological and laboratory data. Comparisons were made between patients affected by CNSI and HAVM and those with favorable and unfavorable outcomes, based on the modified Rankin scale. Gram-positive organisms dominated in CA-CNSI (64%), while gram-negative organisms were more frequent in HAVM (64%). Patients received a median of 30 days of intravenous antibiotics and 11 days of IVT, with no significant difference between CA-CNSI and HAVM. IVT-associated toxicity was rare. Patients with favorable outcomes (64%) had higher initial cerebrospinal fluid- white blood cell count (CSF-WBC), that decreased more rapidly than in patients with unfavorable outcomes. CSF-WBC dynamics did not differ between CA-CNSI and HAVM patients. Rapid decline in CSF-WBC after initiation of IVT was associated with favorable outcome. Despite severe neurological impairment at admission, most survivors achieved favorable long-term outcomes.

From past to present, exploring the applications of mupirocin ointment: A comprehensive review

Mupirocin (MUP), a potent antibacterial agent, has been a cornerstone of topical antimicrobial therapy for several decades. As an older, yet widely used antibiotic, MUP has exhibited efficacy against various bacterial strains, making it a versatile tool in the management of a range of infections. The review synthesizes available literature to highlight the evolution of MUP, from its initial discovery to its current status as a go-to topical antibiotic. In the era of rising antibiotic resistance, MUP is positioned as a valuable therapeutic option due to its broad-spectrum activity against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Emphasis is placed on its distinctive role in different infections, enhanced efficacy with different additives, and newer drug delivery strategies.In addition to its classical applications in impetigo and other superficial skin infections, this review delves into emerging indications and novel uses of MUP, potentially expanding its clinical utility. The exploration of combination therapies, alternative formulations, and ongoing research endeavors will contribute to a forward-looking perspective on the role of MUP in future antimicrobial strategies.

Optimizing Solvent Extraction for Potent Antioxidant and Antidiabetic Activities: A Study on Ampelocissus martini Root

The selection of extraction solvents is a critical factor influencing the composition and concentration of phytochemicals in plant extracts, thereby leading to variations in their biological activities. In this study, Ampelocissus martini Planch., an edible plant traditionally used for its medicinal properties, was investigated for its phytochemical profile and biological activities. We assessed the impact of different solvents used in fractionating the aqueous methanolic root extract of the plant on its phytochemical content, as well as its antioxidant, antidiabetic, and antibacterial properties. Among the 3 fractions—ethyl acetate, butanol, and water-soluble—the butanol fraction exhibited significantly higher levels of total phenolics and proanthocyanidins, while the ethyl acetate fraction contained the highest levels of total flavonoids and saponins. The water-soluble fraction showed lower concentrations of these compounds compared to the other 2 fractions. The butanol fraction demonstrated superior antioxidant activity, outperforming other fractions and several standard antioxidants, as evidenced by DPPH, ABTS, FRAP, and CUPRAC assays. Additionally, the butanol fraction showed greater antidiabetic activity, indicated by a lower IC50 value, although it was still less effective than acarbose, a synthetic antidiabetic drug. Correlation analysis revealed a significant association between total proanthocyanidin content and the observed levels of antioxidant and antidiabetic activities across the fractions. All fractions also exhibited antibacterial activity against Gram-positive bacteria. Based on these findings, butanol emerges as the optimal solvent for extracting specific phytochemicals with potent antioxidant, antidiabetic, and antibacterial activities from the aqueous methanolic extract of A. martini root. The butanol fraction holds promise as a natural source of antioxidants for managing diabetes and its associated complications. HIGHLIGHTS Butanol extract showed strong antioxidant and antidiabetic activities, rich in proanthocyanidins. Strong link was found between proanthocyanidins and bioactivities in A. martini. Butanol fraction showed promise as a natural antioxidant for diabetes management. GRAPHICAL ABSTRACT

Green biogenic synthesis of silver nanoparticles: a thoroughly exploration of characterization and biological efficacy

Conventional physical and chemical methods for synthesizing silver nanoparticles (AgNPs) often use reducing agents, and other chemicals that are harmful to the environment because of their toxic properties. This has prompted significant concern and the need to develop environmentally acceptable approaches. Due to the constraints of traditional chemicalphysical methods, green synthesis methods are being developed to fill these gaps by utilizing biological components extracted from plants. These plant-derived biomolecules are highly specific and facilitate the creation of metal nanoparticles. AgNPs, produced through these methods, possess a wide variety of metabolites with antibacterial effects. In light of this, the current investigation aimed to produce AgNPs using aqueous extracts obtained from Moringa leaves (Ml), Juniper leaves (Jl), and Juniper beans (Jb)via a green chemistry technique. Various analytical methods, including UV-visible spectrophotometry (UV-Vis), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), and energy-dispersive X-ray spectroscopy (EDX) analysis, were employed to characterize the synthesized AgNPs. After adding the plant extracts, the color of the aqueous silver nitrate solution noticeably changed to brown. Furthermore, a shift in absorption spectra was noted, with absorbance peaks appearing around λmax = 449.5 nm, 478.5 nm, and 440.5 nm for Juniper leaves, Jb, and Moringa extracts, respectively. DLS analysis revealed that the synthesized AgNPs varied in size and polydispersity index (PDI) values, with sizes of 108 nm (PDI = 0.246), 101 nm (PDI = 0.278), and 161 nm (PDI = 0.240) form Jl, Jb, and Ml extracts, respectively. These nanoparticles displayed no agglomeration and were stable over a long period. Transmission electron microscope/TEM analysis confirmed the synthesis of well/dispersed AgNPs with an average sizes of less than 22 nm, displaying different shapes likely due to the variety of capping agents present in the bean and leaf extracts. Elemental profiles showed a peak at 3 keV for the synthesized AgNPs, indicating a high proportion of silver elements in all three samples. The synthesized nanoparticles were also subjected to biological screening. The investigation involved testing their antibacterial activity against various bacterial and fungal strains. The Jlnano extract exhibited significant antifungal activity. Conversely, the aqueous and nano-extracts of Ml showed less effectiveness against fungal growth. The plant nano extracts, in particular, demonstrated a clearer effect against all tested fungi compared to the plant aqueous extracts. Among the AgNPs synthesized, those from Moringa extract had the greatest effect on Gram-positive bacteria (S. aureus), with an inhibitory zone diameter of 4.5 mm.

A Comprehensive Review on the Antibacterial, Antifungal, Antiviral, and Antiparasitic Potential of Silybin.

Silybin, a flavonolignan extracted from the seeds of the plant species Silybum marianum (L.) Gaertn., has a variety of pharmacological activities, including antimicrobial activity against several microorganisms of clinical interest. This review analyzes the existing studies on silybin's antimicrobial activity and possible mechanisms of action. Silybin has been shown to inhibit the growth of Gram-positive and Gram-negative bacteria, as well as some fungi, viruses, and protozoa. In general, possible mechanisms of antimicrobial action include the inhibition of efflux pumps, prevention of biofilm formation, reduction of the expression of virulence factors, induction of apoptosis-like effects, and plasma membrane damage, as well as the inhibition of nucleic acid and protein synthesis. Silybin has been shown to have synergistic effects when combined with conventional antibiotics against both drug-sensitive and drug-resistant microorganisms. However, the low bioavailability observed for this flavonolignan has been a challenge to its clinical use. In this context, nanotechnology has been used to increase silybin's bioavailability while enhancing its antimicrobial activity. Furthermore, certain structural modifications have been able to enhance its antimicrobial activity in comparison to that of the natural molecule. Overall, this review provides insights into the scientific understanding of the mechanism of action of silybin and its desired properties for the effective treatment of infections.

Enantiomer-Specific Stable Carbon and Nitrogen Isotopic Analyses of Underivatized Individual l- and d-Amino Acids by HPLC + HPLC Separation and Nano-EA/IRMS.

We developed a new method for stable carbon and nitrogen isotopic (δ13C and δ15N) analysis of underivatized amino acid (AA) enantiomers simultaneously, based on high-performance liquid chromatography (HPLC) separation and off-line isotopic measurement. l- and d-Enantiomers of each AA were isolated using a ReproSil Chiral-AA column, purified by wet chemical procedure, and analyzed for δ13C and δ15N values with a nanomol-scale elemental analyzer/isotope-ratio mass spectrometry (nano-EA/IRMS) system. We successfully achieved the separation of l- and d-enantiomers of 15 proteinogenous AAs, with all l-enantiomers eluting before respective d-enantiomers. The δ13C and δ15N values of AA enantiomers were consistent before and after HPLC separation, demonstrating that this analytical method conserves isotopic information. By coupling this column with a multidimensional HPLC system for isolating individual AAs, we analyzed l- and d-AAs in a natural sample, peptidoglycan isolated from Gram-positive bacterium Bacillus subtilis. Results show a surprisingly large 15N-depletion, up to 20‰, in d-glutamic acid relative to its l-counterpart. The first example, to our knowledge, of δ13C and δ15N analyses of underivatized AA enantiomers is expected to contribute to various research areas in the future.

Magnetic hydrogel scaffold based on hyaluronic acid/chitosan and gelatin natural polymers

Owing to their native extracellular matrix-like features, magnetic hydrogels have been proven to be promising biomaterials as tissue engineering templates In the present work, magnetic hydrogels scaffold based on chitosan, gelatin, hyaluronic acid, containing Fe3O4 as magnetic nanoparticles (IONPs) were prepared. The prepared hydrogels were loaded with ciprofloxacin hydrochloride as a model drug. The magnetic hydrogel was prepared using different volumes of chitosan, 1%, gelatin, 10%, and hyaluronic acid, 1% in glutaraldehyde as the crosslinking agent and Fe3O4 as magnetic nanoparticles. The hydrogel scaffold and magnetic scaffold hydrogel samples were characterized by scanning electron microscopy (SEM), vibrating sample magnetometry (VSM), and Fourier-transform infrared spectroscopy (FTIR). The porosity, mechanical properties, swelling degree, and antibacterial activity of the hydrogel scaffold were also determined as well as the drug release profiles of the hydrogels. SEM imaging revealed that the magnetic hydrogel scaffold showed a relatively rough morphology with an irregular surface. The data obtained indicated that the hydrogel surface has three-dimensional porous microstructures and the porosity varied depending on the hydrogel formulation. The breaking load of the hydrogel scaffold increased from 1.361 Kgf to 4.98 Kgf by increasing the glutaraldehyde concentration from 0.2 mL to 0.8 mL. Swelling degree values in water were from 250 to 2000% after 24 h. The antibacterial activity of the hydrogel scaffold ranged from 54% to about 97% for Gram-positive bacteria (S. aureus) and from about 26–92% for Gram-negative bacteria (E. coli). The ciprofloxacin hydrochloride loaded hydrogel has a sustained release of ciprofloxacin hydrochloride over 10 h. The presence of IONPs gave a faster release of ciprofloxacin hydrochloride.

Diversity, Distribution, and Resistance Profiles of Bacterial Bloodstream Infections in Three Tertiary Referral Hospitals in Rwanda Between 2020 and 2022.

Background: The burden of bacterial bloodstream infections (BSIs) is rapidly increasing in Africa including Rwanda. Methods: This is a retrospective study that investigates the diversity, distribution, and antimicrobial susceptibility profiles of BSI bacteria in three tertiary referral hospitals in Rwanda between 2020 and 2022. Results: A total of 1532 blood culture tests were performed for visiting patients. Overall, the proportions of Gram-negative and Gram-positive bacteria were 48.2% and 51.8, respectively. Staphylococcus aureus was the predominant species accounting for 25% of all Gram-positive BSI species, and Klebsiella species represented 41% of all Gram-negative BSI species. Antimicrobial susceptibility testing revealed that Amikacin exhibited the highest activity against Enterobacter spp., Serratia spp., and Escherichia coli in >92% of cases and Klebsiella spp. in 75.7%. Meropenem and Imipenem were highly efficacious to Salmonella spp. (100% susceptibility), Enterobacter spp. (96.2% and 91.7%, respectively), and Escherichia coli (94.7% and 95.5%, respectively). The susceptibility of Enterococcus spp., S. aureus, and Streptococcus spp. to Vancomycin was 100%, 99.5%, and 97.1%, respectively. Klebsiella spp. was highly sensitive to Colistin (98.7%), Polymyxin B (85.6%), Imipenem (84.9%), and Meropenem (78.5%). Conclusions: We recommend strengthening the implementation of integrated transdisciplinary and multisectoral One Health including AMR stewardship for the surveillance, prevention, and control of AMR in Rwanda.

Gallic acid functionalized silk fibroin/gelatin composite wound dressing for enhanced wound healing

As the incidence of chronic wounds increases, the requirements for wound dressings are rising. The specific aim of this study is to propose a novel gallic acid (GA) functionalized silk fibroin (SF) and gelatin (Gel) composite wound dressing in which GA is used as an antibacterial and wound healing substance. Via electrospinning, SF, Gel, and GA mixed solutions could be conveniently fabricated into a composite nanofiber mat (SF-Gel-GA), consisting of uniform fibers with an average diameter around 134.57 ± 84 nm. The internal mesh structure of SF-Gel-GA provides sufficient drug loading capacity, proper moisture permeability, and proper degradation rate. SF-Gel-GA presents excellent biocompatibility. NIH-3T3 fibroblast cells could adhere and spread stably on the SF-Gel-GA surface with slightly promoted proliferation. In the presence of SF-Gel-GA, the growth of both Gram-positive and Gram-negative bacteria, includingStaphylococcus aureusandPseudomonas aeruginosa, is significantly inhibited in both plate and suspension cultures. A cutaneous excisional mouse wound model proves the efficient ability of SF-Gel-GA to promote wound healing. Compared with pure SF dressing and commercial Tegaderm Hydrocolloid3Mdressing, the wound closure rate with SF-Gel-GA treatment is significantly improved. The histological assessments further demonstrate SF-Gel-GA could facilitate collagen deposition, neovascularization, and epithelialization at wound sites to promote wound healing. In conclusion, a novel SF-Gel-GA composite wound dressing with efficient wound healing activities have been developed for chronic wound treatment with broad healing potential.

Structure of scavenger receptor SCARF1 and its interaction with lipoproteins.

SCARF1 (scavenger receptor class F member 1, SREC-1 or SR-F1) is a type I transmembrane protein that recognizes multiple endogenous and exogenous ligands such as modified low-density lipoproteins (LDLs) and is important for maintaining homeostasis and immunity. But the structural information and the mechanisms of ligand recognition of SCARF1 are largely unavailable. Here, we solve the crystal structures of the N-terminal fragments of human SCARF1, which show that SCARF1 forms homodimers and its epidermal growth factor (EGF)-like domains adopt a long-curved conformation. Then, we examine the interactions of SCARF1 with lipoproteins and are able to identify a region on SCARF1 for recognizing modified LDLs. The mutagenesis data show that the positively charged residues in the region are crucial for the interaction of SCARF1 with modified LDLs, which is confirmed by making chimeric molecules of SCARF1 and SCARF2. In addition, teichoic acids, a cell wall polymer expressed on the surface of gram-positive bacteria, are able to inhibit the interactions of modified LDLs with SCARF1, suggesting the ligand binding sites of SCARF1 might be shared for some of its scavenging targets. Overall, these results provide mechanistic insights into SCARF1 and its interactions with the ligands, which are important for understanding its physiological roles in homeostasis and the related diseases.

Uncovering the arsenal of class II bacteriocins in salivarius streptococci

Facing the antibiotic resistance crisis, bacteriocins are considered as a promising alternative to treat bacterial infections. In the human commensal Streptococcus salivarius, the production of unmodified bacteriocins (or salivaricins) is directly controlled at the transcriptional level by quorum-sensing. To discover hidden bacteriocins, we harnessed here the unique molecular signatures of salivaricins not yet used in available computational pipelines and performed genome mining followed by orthogonal reconstitution and expression. From 100 genomes of S. salivarius, we identified more than 50 bacteriocin candidates clustered into 21 groups. Strain-based analysis of bacteriocin combinations revealed significant diversity, reflecting the plasticity of seven independent loci. Activity tests showed both narrow and broad-spectrum bacteriocins with overlapping activities against a wide panel of Gram-positive bacteria, including notorious multidrug-resistant pathogens. Overall, this work provides a search-to-test generic pipeline for bacteriocin discovery with high impact for bacterial ecology and broad applications in the food and biomedical fields.

The Influence of COVID-19 on Antimicrobial-Resistance in Gram-Positive Bacteria at a Private Saudi Hospital: A Five-Year Evaluation

Due to the emergence of antimicrobial-resistance (AR) as a public health threat, the Saudi National Action Plan (SNAP) was implemented in 2017, incorporating various strategies to combat AR. To evaluate the effectiveness of SNAP and the impact of COVID-19, the study analyzed pre- and post-pandemic rates of AR, methicillin-resistant Staphylococcus aureus (MRSA), and multidrug resistance (MDR) among Gram-positive bacteria at a private medical center in Saudi Arabia. This study reviewed the cases of all patients who had been diagnosed with Gram-positive bacterial infection between January 2017 and December 2021. Bacterial strain identification was conducted using VITEK-2 ID-GP cards, while AR, MRSA, and MDR were defined using AST-GP 67 and AST-ST02 cards, all adhering to the manufacturer’s recommended protocols. The five-year study from 2017 to 2021 yielded 6,271 Gram-positive bacteria isolates from patients in a Saudi private hospital. Though the rate of AR initially declined between 2017 and 2019, it spiked significantly from 2020 to 2021. Similarly, the MRSA rate exhibited a substantial decrease (p < 0.05) from 2017 to 2019, followed by a significant rise (p < 0.05) between 2020 and 2021. Out of the isolated pathogens, 1,031 (16.44%) exhibited MDR, with all isolates showing a marked increase (p < 0.05) in MDR from 2020 to 2021. The study highlights the aggravating impact of the COVID-19 pandemic on AR, underscoring the need for the SNAP to intensify its efforts in combating AR.

Exploring Teucrium aureo-candidum Essential Oil as a Promising Alternative to Triclosan for Targeting Enoyl-Acyl Carrier Protein Reductase: Chemical Composition, Antibacterial Activity, and Molecular Docking Study.

The chemical composition of the essential oil isolated from the aerial parts of Teucrium aureo-candidum, an endemic aromatic shrub collected from Moghrar and Djeniene Bourezg in the Nâama region (Algeria), was determined for the first time using GC/FID and GC/MS. A total of 45 constituents were identified, representing 87.73% of the oil. Characterized by unique chemical variability, it was primarily composed of sesquiterpene hydrocarbons (29.53%) and oxygenated sesquiterpenes (30.06%), with the major compounds being γ-cadinene (5.24%), δ-cadinene (4.24%), α-muurolene (4.04%), τ-muurolol (11.35%), and α-cadinol (3.30%). However, monoterpene hydrocarbons and oxygenated monoterpenes accounted for 23.98% and 1.64%, respectively, contributing to a relatively low fraction. The essential oil demonstrated notable antibacterial activity, particularly against Gram-positive bacteria. Due to safety concerns associated with triclosan, a known inhibitor of the Enoyl-Acyl Carrier Protein Reductase (FabI) enzyme, the essential oil components from this plant were explored as alternatives through a combination of experimental approaches and in silico molecular docking studies. The results revealed that α-cadinol, spathulenol, caryophyllene, and α-muurolene exhibited strong FabI inhibition, with better bioavailability and lower toxicity than triclosan, highlighting their potential in combating antibiotic-resistant bacteria.

Synthesis, Biological Evaluation, and Molecular Docking Studies of Indole-Based Heterocyclic Scaffolds as Potential Antibacterial Agents.

Indole-based heterocyclic scaffolds have become increasingly important in medicinal chemistry due to their notable pharmacological and biological properties. Their role in the discovery and development of innovative drugs for treating various diseases highlights their value. This study aimed to synthesize C3-indole derivatives linked to various heterocyclic scaffolds, including thiophenes, thiazolidine-4-ones, and 1,3,4-thiadiazoles, via the reaction of ethylthioacetanilide 2 with different α-haloketones.The structures of the target compounds were established using 1H and 13C nuclear magnetic resonance spectroscopy, mass spectrometry, infrared spectroscopy, and elemental analysis. The synthesized compounds were tested for antimicrobial activity against different microbes: S. aureus ATCC 6538 (Gram-positive bacteria), E. coli ATCC 25933 (Gram-negative bacteria), C. albicans ATCC 10231 (yeast), and fungi (A. niger NRRL-A326). Thiophene 6a, thiazolidine-4-one 8, and compound 10d exhibited the highest antimicrobial activities. The molecular docking study showed that compounds 2, 4, 6a, and 6c had good binding energy and favorable binding modes of interactions with the DNA gyrase B enzymes (PDB: 3 U2D) and (PDB: 1S14). The results showed that the NH group of the indole in compounds 2 and 4, together with the nitrile group (CN), played an important role in inhibiting DNA gyrase B of S. aureus, PDB: 3 U2D. Furthermore, the NH of the indole ring, together with the ethylamino group of compound 2, was crucial in inhibiting DNA gyrase B of E. coli, PDB: 1S14. These findings may encourage researchers to develop more effective C3-indole derivatives in their search for antimicrobial drugs.