Gram-positive Research Articles

Long-term mold resistance strategy of laccase-catalyzed eugenol-modified bamboo and its antimicrobial mechanism derived from lignin

Bamboo, which has excellent physical properties and environmental credentials, is widely used in the construction industry and furniture manufacturing. Bamboo is, however, susceptible to attack by molds and bacteria; protection by natural phenolic antimicrobial agents would be a green and environmentally friendly solution to this problem. The application of such protection has, so far, been hampered by poor stability and ease of volatilization of the antimicrobial agent. Here, an innovative strategy that uses the catalytic action of the laccase to chemically attach a natural antimicrobial agent, eugenol (EU), to bamboo, is described. This modification endows bamboo with both long-lasting and extensive mold resistance and antibacterial activity. Laccase-catalyzed covalent bonding of EU to bamboo reduces the volatilization rate of the EU from 1.72 % to 0.29 %. The outstanding mold resistance and antimicrobial activity of bamboo treated using this modified process is retained during a 50-day mold resistance test, with mold growth inhibited by as much as 87.5 %. The treated bamboo is also able to inhibit the growth of both Gram-positive and Gram-negative bacteria. The antimicrobial mechanism results shown that the bamboo lignin is the primary reaction site during laccase-catalyzed EU modification of bamboo, and the long-term mold resistance derived from modified lignin. Furthermore, we analyzed bacterial morphology through SEM, and the results demonstrated that modified enzymatic hydrolysis lignin (EHL) significantly disrupts bacterial morphology, including membrane invagination and collapse. This study provides a new direction for the green development of mold- and bacteria-resistant bamboo, which has potential for use in a wide range of application.

The absence of luxS reduces the invasion of Avibacterium paragallinarum but is not essential for virulence.

The contagious respiratory pathogen, Avibacterium paragallinarum, contributes to infectious coryza in poultry. However, commercial vaccines have not shown perfect protection against infectious coryza. To search for an alternative approach, this research aimed to investigate whether the quorum-sensing system of pathogens plays a crucial role in their survival and pathogenicity. The LuxS/AI-2 quorum-sensing system in many Gram-negative and Gram-positive bacteria senses environmental changes to regulate physiological traits and virulent properties, and the role of the luxS gene in Av. paragallinarum remains unclear. To investigate the effect of the luxS gene in the quorum-sensing system of Av. paragallinarum, we constructed a luxS mutant. Bioluminescence analysis indicated that the luxS gene plays a vital role in the LuxS/AI-2 quorum-sensing system. The analysis of the LuxS/AI-2 system-related genes showed the level of pfs mRNA to be significantly increased in the mutant strain; however, lsrR, lsrK, and lsrB mRNA levels were not significantly different compared with the wild type. The ability of the luxS mutant strain to invade HD11 and DF-1 cells was significantly decreased compared with the wild-type strain. In addition, all chickens challenged with various doses of the luxS mutant strain developed infections and symptoms, and those challenged with the lowest dose exhibited only minor differences compared to chickens challenged with the wild-type strain. Thus, the deletion of the luxS gene reduces the invasion, but the luxS gene does not play an essential role in the pathogenesis of A. paragallinarum.

A group B streptococcal type VII-secreted LXG toxin mediates interbacterial competition and colonization of the murine female genital tract.

Group B Streptococcus (GBS) asymptomatically colonizes the vagina but can opportunistically ascend to the uterus and be transmitted vertically during pregnancy, resulting in neonatal pneumonia, bacteremia, and meningitis. GBS is a leading etiologic agent of neonatal infection and understanding the mechanisms by which GBS persists within the polymicrobial female genital mucosa has the potential to mitigate subsequent transmission and disease. Type VIIb secretion systems (T7SSb) are encoded by Bacillota and often mediate interbacterial competition using LXG toxins that contain conserved N-termini important for secretion and variable C-terminal toxin domains that confer diverse biochemical activities. Our recent work characterized a role for the GBS T7SSb in vaginal colonization and ascending infection but the mechanisms by which the T7SSb promotes GBS persistence in this polymicrobial niche remain unknown. Herein, we investigate the GBS T7SS in interbacterial competition and GBS niche establishment in the female genital tract. We demonstrate GBS T7SS-dependent inhibition of mucosal pathobiont Enterococcus faecalis both in vitro using predator-prey assays and in vivo in the murine genital tract and found that a GBS LXG protein encoded within the T7SS locus (herein named group B streptococcal LXG Toxin A) contributes to these phenotypes. We identify BltA as a T7SS substrate that is toxic to E. coli and S. aureus upon induction of intracellular expression along with associated chaperones. Finally, we show that BltA and its chaperones contribute to GBS vaginal colonization. Altogether, these data reveal a role for a novel T7b-secreted toxin in GBS mucosal persistence and competition.IMPORTANCECompetition between neighboring, non-kin bacteria is essential for microbial niche establishment in mucosal environments. Gram-positive bacteria encoding T7SSb have been shown to engage in competition through the export of LXG-motif-containing toxins, but these have not been characterized in group B Streptococcus (GBS), an opportunistic colonizer of the polymicrobial female genital tract. Here, we show a role for GBS T7SS in competition with mucosal pathobiont Enterococcus faecalis, both in vitro and in vivo. We further find that a GBS LXG protein contributing to this antagonism is exported by the T7SS and is intracellularly toxic to other bacteria; therefore, we have named this protein group B streptococcal LXG Toxin A (BltA). Finally, we show that BltA and its associated chaperones promote persistence within female genital tract tissues, in vivo. These data reveal previously unrecognized mechanisms by which GBS may compete with other mucosal opportunistic pathogens to persist within the female genital tract.

The evolution of knowledge for treating Gram-negative bacterial infections.

Infections caused by nonprimarily pathogenic Gram-negative bacilli (GNB) have been increasingly reported from the second half of the 20th century to the present. This phenomenon has expanded during the antibiotic era and in the presence of immunodeficiency.Before the discovery of sulphonamides and penicillin G, infections caused by GNB were rare compared to Gram-positive infections. The advent of anticancer therapy, the expansion of surgical procedures, the use of corticosteroids, and the implantation of prosthetic materials, along with better control of Gram-positive infections, have promoted the current increase in GNB infections.GNB have similar antimicrobial targets to Gram-positive bacteria. However, only antibiotics that can penetrate the double membrane of GNB and remain in them for a sufficient duration have antibacterial activity against them. Sulphonamides and early penicillins had limited activity against GNB. Ampicillin and subsequent beta-lactams expanded their spectrum to treat GNB. Aminoglycosides may re-surge with less toxic drugs, as highly resistant to beta-lactams GNB rise. Polymyxins, tetracyclines, and fluoroquinolones are also used for GNB. Combinations with other agents may be needed in specific cases, such as in the central nervous system and prostate, where beta-lactams may have difficulty reaching the infection site.Alternatives to current treatments must be sought in the discovery of new drug families and therapies such as phage therapy combined with antibiotics. Narrower-spectrum immunosuppressive therapies and antibiotics, antimicrobials that minimally intervene with the human microbiota, and instant diagnostic methods are necessary to imagine a future where currently dominant bacteria in infectious pathology lose their preeminence.

Discovery and Biosynthesis of Persiathiacins: Unusual Polyglycosylated Thiopeptides Active Against Multidrug Resistant Tuberculosis.

Thiopeptides are ribosomally biosynthesized and post-translationally modified peptides (RiPPs) that potently inhibit the growth of Gram-positive bacteria by targeting multiple steps in protein biosynthesis. The poor pharmacological properties of thiopeptides, particularly their low aqueous solubility, has hindered their development into clinically useful antibiotics. Antimicrobial activity screens of a library of Actinomycetota extracts led to discovery of the novel polyglycosylated thiopeptides persiathiacins A and B from Actinokineospora sp. UTMC 2448. Persiathiacin A is active against methicillin-resistant Staphylococcus aureus and several Mycobacterium tuberculosis strains, including drug-resistant and multidrug-resistant clinical isolates, and does not significantly affect the growth of ovarian cancer cells at concentrations up to 400 μM. Polyglycosylated thiopeptides are extremely rare and nothing is known about their biosynthesis. Sequencing and analysis of the Actinokineospora sp. UTMC 2448 genome enabled identification of the putative persiathiacin biosynthetic gene cluster (BGC). A cytochrome P450 encoded by this gene cluster catalyzes the hydroxylation of nosiheptide in vitro and in vivo, consistent with the proposal that the cluster directs persiathiacin biosynthesis. Several genes in the cluster encode homologues of enzymes known to catalyze the assembly and attachment of deoxysugars during the biosynthesis of other classes of glycosylated natural products. One of these encodes a glycosyl transferase that was shown to catalyze attachment of a D-glucose residue to nosiheptide in vitro. The discovery of the persiathiacins and their BGC thus provides the basis for the development of biosynthetic engineering approaches to the creation of novel (poly)glycosylated thiopeptide derivatives with enhanced pharmacological properties.

Interaction Between Endometriosis and Bacteria in Infertile Women at Arash Women's General Hospital in Tehran

Background: Endometriosis is a common disorder that affects 20 - 50% of infertile women. The disease correlates with the presence of lactobacilli and changes in the number of gram-negative and gram-positive bacteria. Objectives: This article aims to investigate the interaction between endometriosis and certain bacteria. Methods: One hundred women between 18 and 40 years of age referred to the IVF department of Arash Women's Hospital in Tehran were studied. Fifty of them were diagnosed with endometriosis, while the rest were referred for investigation or freezing of their gametes or embryos. Specimens were collected from endometrial tissue and the cervix using swabs. These specimens were used for cultures and real-time PCR to quantify Lactobacillus. Results: Seventeen different gram-positive and gram-negative bacteria, as well as three yeasts, were isolated from women with and without endometriosis. The highest prevalence was related to Enterococcus faecalis, followed by Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, E. faecium, Proteus mirabilis, Edwardsiella tarda, and Citrobacter spp. In cases with endometriosis, the relationship between the increase of Enterococcus spp., members of the Enterobacteriaceae family, and the decrease of lactobacilli was significant (P < 0.05). Staphylococcus aureus was isolated from the cervix of three women with endometriosis. The bacterial profiles of the cervix and endometrium were very similar. Conclusions: Considering the decrease of lactobacilli and the increase of other bacteria in people with endometriosis, it is recommended to use Lactobacillus and other probiotics for the prevention and even treatment of this disease.

The effect of layering order of ZIF-8@PCL/PLA composites in electrospinning and electrospraying process on antibacterial wound healing

The imidazolate-zeolite framework-8 (ZIF-8), as a zinc-based metal-organic framework, can act as an antibacterial agent by releasing Zn2+ ions. In this project, utilizing this previously studied fact, a set of wound dressings has been prepared using polycaprolactam and polylactic acid. Electrospinning and electro-spraying processes have been employed to create these samples. In total, five samples were obtained with variations in the layering sequence, and all samples were tested against two bacteria: Staphylococcus aureus and Escherichia coli. The results indicated that all samples were effective against the Gram-positive bacterium S. aureus, with the sample produced by simultaneous electro-spraying and electrospinning exhibiting the highest lethality rate. However, only the sample with the sequence of polycaprolactam layer, polylactic acid, and then ZIF-8 succeeded in eliminating 99 % of E. coli. The produced products were characterized using powder X-ray diffraction, IR spectroscopy, and scanning electron microscopy. The antibacterial effect of these wound dressings was evaluated using direct counting of bacterial colonies.

Abietane diterpenoid salvipisone: Structure elucidation, conformational analysis, and antimicrobial activity

Salvipisone, an abietane diterpenoid, was isolated from the roots of Salvia aethiopis L. using a combination of chromatographic separation techniques. Its structure was elucidated employing a variety of spectroscopic methods, including ultraviolet (UV), infrared (IR), 1D and 2D nuclear magnetic resonance (NMR), and mass spectrometry. A comprehensive analysis of experimental 1D and 2D NMR data, incorporating 1H iterative full spin analysis and higher-order multiplet simulation, revealed discrepancies with previously reported NMR data for this compound. Detailed examination of the 1H NMR spectrum's spin-spin coupling structure provided insights into the relative populations of the three staggered conformers around the C12–C13 bond at room temperature. The conformer populations were determined using the relationship between the experimental values for vicinal coupling constants and the estimated ones for the preferred staggered conformers, yielding a ratio of approx. 80:4:16 for anti, gauche, and gauche′-conformers, respectively. Possible reasons for the observed unevenly populated staggered conformers were also discussed. The antimicrobial activity of salvipisone was evaluated using in vitro and in silico methods. In vitro antimicrobial assays demonstrated that salvipisone exhibited the highest inhibitory effect against Staphylococcus aureus ATCC and Enterococcus faecalis ATCC (MIC = 3.125 μg/mL), followed by Bacillus subtilis ATCC (MIC = 6.25 μg/mL). In contrast, concentrations above 100 μg/mL were necessary to inhibit Escherichia coli ATCC and Klebsiella pneumoniae ATCC. In silico studies suggested that salvipisone, particularly its keto form, has significant potential for inhibiting the enzyme gyrase, highlighting its mechanism of antimicrobial action. Our findings highlight the promising antimicrobial and inhibitory properties of salvipisone, particularly against Gram-positive bacteria such as S. aureus.

Isolation of 2,2'-azoxybisbenzyl alcohol from Agaricus subrutilescens and its inhibitory activity against bacterial biofilm formation.

Virulence pathways in pathogenic bacteria are regulated by quorum sensing mechanisms, particularly biofilm formation through autoinducer (AI) production and sensing. In this study, the culture filtrate extracted from an edible mushroom, Agaricus subrutilescens, was fractionated to isolate a compound that inhibits biofilm formation. Four gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, and Enterobacter cloacae) and two gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus) were used for the bioassay. The bioassay-guided chromatographic separations of the culture filtrate extract resulted in the isolation of the compound. Further, spectroscopic analyses revealed the identity of the compound as 2,2'-azoxybisbenzyl alcohol (ABA). The minimum inhibitory and sub-inhibitory concentrations of the compound were also determined. Azoxybisbenzyl alcohol was significantly effective in inhibiting biofilm formation in all tested bacteria, with half-maximal inhibitory concentrations of 3-11µg/mL. Additionally, the bioactivity of ABA was confirmed through the bioassays for the inhibition of exopolysaccharide matrixes and AI activities.

Bacteria and Cyanobacteria Inactivation Using UV-C, UV-C/H2O2, and Solar/H2O2 Processes: A Comparative Study

Effective disinfection processes have been investigated to provide pathogen-free drinking water. Due to growing concern about the potential negative effects of cyanobacteria in portable water, their treatment has gained more attention recently. This study aims to compare the inhibition efficiencies of Gram-negative bacteria (Escherichia coli; E. coli), Gram-positive bacteria (Bacillus subtilis; B. subtilis), and cyanobacteria (Microcystis aeruginosa; M. aeruginosa) using UV-C and solar irradiation, and their combination process with H2O2. Over 6 log removal value (LRV) of E. coli and B. subtilis was achieved within 1 min of UV-C irradiation (0.76 ± 0.02 mW/cm2). The solar and solar/H2O2 (50 mg/L) processes effectively reduced (>99%) both bacteria after 20 min. E. coli was more sensitive to hydroxyl radicals (•OH) compared to the B. subtilis due to a different cell wall structure, resulting in a 0.18–0.62 higher LRV than B. subtilis. However, solar-based processes did not effectively inhibit M. aeruginosa (>52.23%). The UV-C/H2O2 (50 mg/L) process showed the highest inhibition rate for M. aeruginosa (77.83%) due to the generation of •OH, leading to oxidative damage to cells. Additionally, chlorophyll-a (Chl-a) was measured to indicate cell lysis of M. aeruginosa. The removal rate of Chl-a extracted by viable M. aeruginosa was higher using the UV-C process (93.03%) rather than the UV-C/H2O2 process (80.95%), because UV-C irradiation could be most effective in damaging Chl-a.

Antimicrobial effectiveness of chestnut honey, pollen and propolis individually and in combination

The emergence of bacteria with antibiotic resistance and multiple resistance is characteristic of animal and human pathogens. It is wide known that bee products, which have been used in alternative medicine since ancient times, have antimicrobial potential. Application of bee products for therapeutic purposes is defined as apitherapy. The study aimed to evaluate the antimicrobial activity of commercial chestnut honey, pollen and propolis produced in western Bosnia and Herzegovina (Sanski Most) individually and in five combinations (apimixtures). The antimicrobial properties of samples were investigated using the agar well diffusion method against three Gram-positive bacteria (Bacillus subtilis subsp. spizizenii ATCC 6633, Methicillin-resistant Staphylococcus aureus ATCC 33591, Enterococcus faecalis ATCC 29212); three Gram-negative bacteria (ESBL producing Escherichia coli ATCC 35218, Salmonella enterica subsp. enterica serovar Enteritidis ATCC 13076, Pseudomonas aeruginosa ATCC 9027) and one fungal species (Candida albicans ATCC 10231). Pure bee pollen inhibited the growth of only Gram-negative bacteria, concentrated chestnut honey was active against all Gram-negative and Gram-positivebacteria, while 20% propolis extract and apimixtures A2 (80% honey and 20% propolis) and A3 (60% honey, 20% pollen and 20% propolis extract) inhibited the growth of all tested microorganisms. Chestnut honey andthree apimixtures (A1, A2 and A3) showed the highest antibacterial action against all tested Gram-negative bacteria and MRSA compared to other investigated samples. In this study, examined honeybee products from Bosnia and Herzegovina and their mixtures had significant activity against tested bacteria, including strains with proven resistance to conventional antibiotics, MRSA and ESBL producing E. coli.

The Isolation and Identification of Novel Arsenic-Resistant Bacteria from an Arsenic-Contaminated Region—A Study to Understand the Efficiency of Bacteria for Arsenic Removal from Aqueous Media

Drinking water sources with groundwater arsenic (As) contamination face multifaceted challenges in the removal and supply of fresh drinking water resources. To eradicate this problem, bioremediation has evolved to become more effective than other chemical and physical removal processes in its cost-effectiveness, high removal efficiency, and lesser production of secondary by-products or waste. Thus, this study aimed to treat As from aqueous media and to detoxify highly toxic forms of As by the isolated bacteria from As-affected areas. We isolated two new Gram-positive bacteria, which are reported here (Bacillus sp. and Bacillus cereus), with As5+ minimum inhibitory concentrations (MICs) of 4500 mg/L for the Bacillus sp. and 1000 mg/L for Bacillus cereus; meanwhile, for As3+, the MICs are 600 mg/L for both isolates. Bacillus sp. and Bacillus cereus can also effectively convert the highly toxic and easily mobile As3+ to As5+ in aqueous media. This study also demonstrates that these bacteria can remove a significant proportion of As3+ and As5+ (averaging 50% for both) from aqueous media. These As-resistant bacteria from the As-affected area can be used and upscaled for the treatment of As for a safer drinking water supply.

Asian Spice Nanotech: Illicium verum made Metal Nanoparticles for Potent Antibacterial and Catalytic Applications

Introduction: Asian spices are globally recognized for their rich phytochemical composition. The bioactive compounds of Asian spices have significant potential to extend the biological applications of metal nanomaterials by increasing their surface area, stability, dispersion, and ecofriendliness. Method: The present study is designed to prepare novel iron oxide (Fe2O3) and copper oxide (CuO) nanoparticles using an aqueous extract of Illicium verum (star anise), a traditional Asian spice as a reducing, capping & stabilizing agent. The synthesized nanoparticles have been characterized to study their molecular environment using Fourier-transform infrared spectroscopy (FTIR). Elemental composition was examined through the Energy dispersive X-ray Spectroscopy (EDS). Scanning Electron Microscopy (SEM) revealed the size, shape, and other morphological characteristics of nanoparticles. The optical properties have been tested through Ultraviolet-Visible (UV) spectroscopy and the band gap energies of both Fe2O3 and CuO nanoparticles have been calculated by using the Tauc plot method, which explores its semiconductor applications. The catalytic applications of obtained nanoparticles have shown significant potential in the degradation of aqueous methyl orange dye (MO). Results: Results revealed that Fe2O3 and CuO nanoparticles significantly increased the rate of reaction by decreasing the reaction time to 45 mins and 40 mins, respectively in comparison to the NaBH4 (60 mins). This shows that CuO has a larger surface area and more absorption capacity than Fe2O3 NPs. To examine the cause of value healthcare, the obtained materials have also been applied against various Gram-positive and Gram-negative bacteria. The bactericidal activity was compared with gentamicin, which showed both nanometals are moderate to strongly active against tested microbes. Conclusion: The successful eco-friendly synthesis of metallic nanoparticles by using Asian spices and their applications in physical and biological sciences opens the door for the scientific community to develop and apply more novel and green nanomaterials in industrial and commercial areas.

Antibacterial Application of Copper Nanoparticles Biosynthesized by Water Caltrop Pod.

This study investigates the utilization of water caltrop pod, an abundant agricultural waste product, as a green extract for the optimized biosynthesis of copper nanoparticles (CuNPs). To comprehensively characterize the water caltrop pod and the biosynthesized CuNPs by water caltrop pod a sophisticated techniques were employed, including U.V-Vis spectrophotometry for probing their preliminary analysis of copper nanoparticles, FT-IR spectroscopy for elucidating the functional groups present in water caltrop pod, Scanning Electron Microscopy (SEM) for visualizing the morphology, Energy Dispersive X-ray (EDX) for elemental analysis while Energy-Dispersive X-ray (XRD) to determine crystalline structure of copper nanoparticles. Furthermore, the antibacterial application of these biogenic copper nanoparticles was explored. The antibacterial activity of copper nanoparticles (CuNPs) was investigated against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, revealing their efficacy in combating microbial growth employing a Well Diffusion method. Copper nanoparticles showed greater antibacterial treatment against Gram (+ve) bacteria i.e. Staphylococcus aureus as compared to Gram (-ve) bacteria i.e. Escherichia coli. This research paves the way for the sustainable production of bio-functional CuNPs from waste biomass, offering promising application in antibacterial therapies.

Burden of multidrug-resistant bacteria among HIV-positive individuals in Ethiopia: A systematic review and meta-analysis.

Multidrug-resistant (MDR) bacteria are a significant cause of severe infections, particularly in human immunodeficiency virus (HIV)-positive individuals because of their weakened immunity. Since there was no previous pooled representative data regarding the MDR bacteria among HIV-positive individuals in Ethiopia, this systematic review and meta-analysis is required. This study was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A literature search was performed using PubMed, Medline, EMBASE, Google Scholar, Hinari, Web of Science, Science Direct, and African Journals Online databases. Data were extracted using Microsoft Excel 2019 and analyzed using STATA version 11.0 software. A random-effects model was used to estimate the pooled effect size of outcome variables across studies with a 95% confidence interval. The I2 statistic was used to check for heterogeneity. The presence of publication bias was determined using a funnel plot and Egger's test with a p-value < 0.05 evidence of statistically significant bias. The pooled prevalence of MDR was 58.02% (95% CI: 46.32-69.73%) with high heterogeneity (I2 = 97.1%, (p < 0.001). In subgroup analysis, the highest multi-drug resistance was observed in the Oromia region (80.95%), patients with multiple infections (82.35%), and studies identified both Gram-positive and Gram-negative bacteria (61.45%). Furthermore, the pooled prevalence of MDR bacteria colonizing HIV-positive individuals was 48.76%. Regarding MDR species, Enterococci (77.41%) and Pseudomonas spp. (84.60%) were commonly identified in individuals with HIV infection. Our study indicates a high burden of MDR among HIV-positive individuals in Ethiopia. The Oromia region, HIV patients with multiple infections, Pseudomonas spp., and Enterococci showed the highest MDR in the subgroup analysis. Therefore, regional hospitals should implement strategies to tackle MDR such as vaccination program, appropriate use of antibiotics, and further study on the associated factors of MDR bacteria in HIV are required.

Anti-Inflammatory and Antimicrobial Activity of Silver Nanoparticles Green-Synthesized Using Extracts of Different Plants.

In this study, an easy, efficient, economical, and eco-friendly green bio-synthesis method was utilized to synthesize silver nanoparticles (AgNPs) using the extracts of four plants: Ginkgo biloba, Cichorium Intybus, Adiantum Capillus-Veneris, and Rosmarinus Officinalis. The synthesis of AgNPs was confirmed by using a uv-vis spectrometer, which showed distinct surface plasmon resonance (SPR) bands. The surface of AgNPs was characterized using scanning electron microscopy and Fourier-transform infrared spectroscopy. The anti-inflammatory activity of Tenoxicam/Meloxicam-loaded AgNPs has been studied using the inhibition of albumin denaturation method. Tenoxicam-loaded AgNPs showed higher % Inhibition, but Meloxicam-loaded AgNPs showed lower % Inhibition. Furthermore, the AgNPs showed excellent antimicrobial activity on both Gram-negative and Gram-positive bacteria.

Combination of High-Dose Daptomycin and Ceftriaxone for Cardiac Implantable Electronic Device Infections: A 10-Year Experience

PurposeCardiac implantable electronic device (CIED) infections are increasingly common. Gram-positive bacteria such as coagulase negative staphylococci and Staphylococcus aureus are the most commonly involved pathogens. The aim of this study was to describe the characteristics and outcome of patients with CIED infections who underwent device removal and were empirically treated with high dose (8–12 mg/kg daily) daptomycin (DAP) in combination with ceftriaxone (CRO). MethodsRetrospective, single center study including patients admitted at IRCCS San Raffaele Hospital (Milan, Italy), from June 2011 to June 2021, who underwent device removal for CIED infection and were empirically treated with DAP/CRO. FindingsOverall, 147 patients were included in this study. Median duration of therapy was 16 days (IQR 14–26). Empirical treatment with DAP/CRO was confirmed as definitive treatment in 140 patients (95.2%). In 7 (4.8%) patients DAP/CRO were discontinued according to the definite microbiological isolates: Corynebacterium spp. (4), Pseudomonas aeruginosa (2), Enterobacter cloacae (1). Ten patients (6.8%) underwent treatment simplification to narrow-spectrum antibiotics. One patient (0.6%) interrupted DAP-CRO due to pancytopenia.6-month follow-up was available for 123/147 patients (83.7%): 9 patients recurred with a CIED infection (7.3%), and 9 died (7.3%). ImplicationsIn our 10-year experience, high-dose DAP in combination with CRO represented a good option for empirical therapy of CIED infections. DAP-CRO combination was safe and effective, showing no significant drug-related adverse events and low rates of 6-month recurrence and mortality.

Chemical composition, antimicrobial and antibiofilm activities of essential oil from Turkish endemic Prangos hulusii fruits

ABSTRACT The chemical composition, antimicrobial, and antibiofilm activities of the essential oil from the fruits of Turkish endemic Prangos hulusii were studied. Essential oil was analyzed by GC and GC/MS. Thirty-nine compounds were identified, which represent 98.6% of the total composition of the essential oil. Monoterpene hydrocarbons and sesquiterpene hydrocarbons were the most represented classes of volatiles with 49.8% and 21.0%, respectively. The main constituents of the essential oil were (E)-methyl cinnamate (22.9%), α-phellandrene (13.8%), and (E)-β-ocimene (12.9%). (E)-methyl cinnamate was detected in Prangos spp. for the first time. Antimicrobial activities against three Gram-positive bacteria, three Gram-negative bacteria, and three yeast strains were evaluated using disk diffusion test and microdilution method. Antibiofilm experiments were done by spectrophotometric microplate method and the results of Staphylococcus aureus, Escherichia coli, and Candida albicans were visualized via scanning electron microscopy. The essential oil had an antimicrobial effect and showed an antibiofilm effect on these strains.

Biosynthesis of Zinc Oxide Nanoparticles Using Garlic Peel Extract and Their Antibacterial Potential

Zinc oxide nanoparticles (ZnO NPs) have gathered interest because of their unique characteristics and potential applications. In the current work, ZnO NPs underwent an eco-friendly biosynthesis process using garlic peel extract. The biosynthesized ZnO NPs were characterized using different analyses including Ultraviolet-visible (UV-vis) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). The produced ZnO NPs exhibited a UV–vis spectrum absorption peak at 365 nm, thus indicating the formation of ZnO NPs. The SEM showed that the biosynthesized ZnO NPs had an irregular surface morphological shape with an average size of 17 nm, according to the DLS analysis. Based on the FTIR findings, the bioactive functional groups responsible for stabilizing and capping the ZnO-NPs were confirmed. The biosynthesized ZnO NPs exhibited 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and antimicrobial activities against Gram-positive (Bacillus cereus) and Gram-negative bacteria (Klebsiella pneumonia). Therefore, the plant-mediated biosynthesized ZnNPs can be considered a promising candidate as an antioxidant and antimicrobial agent against pathogenic microbes found in different areas such as food safety and agriculture. Through the utilization of bioinformatics, we identified six potential targets for drug development in K. pneumonia and B. cereus, along with their corresponding interacting residues with zinc oxide nanoparticles. Additionally, our research revealed that the zinc oxide nanoparticles exhibited binding capabilities with the sulfiredoxin domain located at the specific targets of K. pneumonia, a crucial mechanism responsible for the repair of bacterial cells under oxidative stress.

Realtime bacteria detection and analysis in sterile liquid products using deep learning holographic imaging

We introduce a digital inline holography (DIH) method combined with deep learning (DL) for real-time detection and analysis of bacteria in liquid suspension. Specifically, we designed a prototype that integrates DIH with fluorescence imaging to efficiently capture holograms of bacteria flowing in a microfluidic channel, utilizing the fluorescent signal to manually identify ground truths for validation. We process holograms using a tailored DL framework that includes preprocessing, detection, and classification stages involving three specific DL models trained on an extensive dataset that included holograms of generic particles present in sterile liquid and five bacterial species featuring distinct morphologies, Gram stain attributes, and viability. Our approach, validated through experiments with synthetic data and sterile liquid spiked with different bacteria, accurately distinguishes between bacteria and particles, live and dead bacteria, and Gram-positive and negative bacteria of similar morphology, all while minimizing false positives. The study highlights the potential of combining DIH with DL as a transformative tool for rapid bacterial analysis in clinical and industrial settings, with potential extension to other applications including pharmaceutical screening, environmental monitoring, and disease diagnostics.