Antimicrobial Research Articles

Spontaneous brain abscess formation: challenge of a shifting pathogen spectrum over the last 21 years – a single center experience

BackgroundSpontaneous intracerebral abscess formation is a rare condition presenting with a disabling sequela. The origin of infection can either be primary or secondary to an infection at another location. The site of primary infection - due to the proximity, often the oral cavity, the sinuses, and the orbit - determines the causative pathogens. Treatment often combines surgical and antimicrobial therapies. To determine the microbiology and respective changes and treatment outcome, we performed this retrospective monocentric cohort study of patients requiring surgical treatment of brain abscesses.MethodsPatients undergoing surgical treatment of a primary intracranial abscess between January 2000 and January 2021 in the Department of Neurosurgery, Freiburg University Hospital were included. Demographic, clinical and imaging data were extracted from patients’ medical records and databases. Treatment approaches were also analyzed, and surgical therapy and antibiotic therapy were reported. Outcome was assessed by the modified Rankin score (mRS) and was dichotomized into good (mRS 0–3) and poor (mRS 4–6) outcome.ResultsWe included 65 patients with spontaneous intracerebral abscess that were treated with neurosurgical intervention at our institution. Analysis of the causative pathogens showed an increasing dominance of rare pathogens such as fungi, parasites, mycobacteria and anaerobes. Outcome measured by the mRS was similar from 2005 to 2021.ConclusionsThe pathogen spectrum of spontaneous intracerebral abscess at our institution is shifting with rarer pathogens being increasingly detected. This retrospective analysis highlights the need for microbiological diagnosis and of combined surgical and antibiological treatment.

PERFIL MICROBIOLÓGICO DAS INFECÇÕES RELACIONADAS À ASSISTÊNCIA À SAÚDE EM HOSPITAIS UNIVERSITÁRIOS: REVISÃO DE LITERATURA

Considering that healthcare-associated hospital infections (HAIs) are acquired 48 hours after hospital admission, or manifest within 3 days after hospital discharge, they may be associated with healthcare prophylaxis, causing an impact on the health of the patient. patient, family, hospital institutions and even society as a whole. The main objective of this work was to evaluate the bacterial incidence of surfaces and equipment in emergency rooms, medication rooms, intermediate care rooms and surgical blocks at a university hospital. Hospital infections represent a challenge when it comes to clinical practice regarding hospitalized patients. Its parameter determines a considerable increase in the hospitalization period, in lethality and, at the same time, contributes to high hospital costs. Hospitalized patients, specifically in the Intensive Care Unit, are particularly more exposed to hospital infections, given their clinical conditions, which require invasive procedures and antimicrobial therapy. This study aimed to observe and determine the prevalence of nosocomial infection (HI) distributed across sectors of a tertiary hospital in Pernambuco, specialized as a day hospital, which offers consultations in different specialties such as Anesthesiology, Cardiology, General Surgery, Vascular Surgery, Internal Medicine, Urology among the different specialties. Data collection was carried out, with a retrospective of these exams on hospitalized patients from 2019 to 2023.

An in-depth analysis of antimicrobial prescription quality in 10 non-university hospitals, in southwest Germany, 2021.

BackgroundNon-university hospitals are the major provider of inpatient care in Germany, serving 89% of acute care hospital beds. Although surveillance data on antimicrobial use in hospitals are widely available, data on prescription quality are rare.AimWe aimed to provide an in-depth analysis of antimicrobial prescribing patterns and quality in southwest German non-university hospitals.MethodsDuring 2021, we performed three point prevalence surveys (PPS) in 10 non-university hospitals, representing ca 10% of hospital beds in the federal state of Baden-Württemberg (11 million inhabitants). Demographic and clinical information were collected. We assessed the overall performance of 14 validated process quality indicators (QI) covering infection diagnostics, antimicrobial therapy and documentation.ResultsOf 8,560 patients analysed, 2,861 (33%) received at least one antimicrobial. Most (2,789, 80%) antimicrobial prescriptions were for therapeutic indications. Most frequently prescribed agents were beta-lactam/beta-lactamase inhibitors (1,120, 40%) in therapeutic and cefuroxime (269, 37%) in prophylactic indications. According to the World Health Organization's Access, Watch, Reserve classification, the Access-to-Watch ratio was 0.73. Overall adherence to QIs was low and varied substantially (27-93%), with documentation, possible streamlining and switching to oral therapy exhibiting the lowest fulfilment rates (<50%).ConclusionThe results indicate a need to improve antimicrobial prescribing quality in non-university hospitals. The high prevalence of antimicrobial use in our setting underlines the demand for sustainable antimicrobial stewardship programmes in this sector. Our QI-based PPS approach can be used to identify key targets for future antimicrobial stewardship interventions. The results indicate a need for further legislation on antimicrobial stewardship.

Hemodynamic periodontal changes in the treatment of chronic generalized periodontitis using polarized polychromatic light

Background: Ineffective treatment of inflammatory periodontal diseases is a significant medical and social issue. Previous research have shown that improved vascular response and local immunity activation are crucial for the treatment of periodontal diseases. This can be accomplished using polarized polychromatic light. However, the effect of polarized polychromatic light on microhemocirculation in periodontal tissues is poorly understood. Aim: To assess microhemodynamic changes in periodontal tissues in the treatment of mild chronic generalized periodontitis using polarized polychromatic light. Materials and Methods: A complex dental examination and treatment were performed in 70 patients (32 males and 38 females) with active chronic generalized periodontitis aged 20 to 59 years. The study had two groups (35 subjects each) based on treatment approaches. Group 1 received professional oral care and a course of antimicrobial therapy using Dentamet dental gel. Group 2 received antimicrobial therapy in combination with polarized polychromatic light therapy (wavelength 480–3,400 nm, power 40 mW/cm2, flux density 2.4 J/cm2 per minute, polarization 95%). Laser Doppler flowmetry was used to assess hemodynamics before treatment, as well as 3, 6, and 12 months after treatment. Results: Group 1 demonstrated an improvement in microcirculation parameters for up to 3 months (p=0.0027). In group 2, an improvement was observed for up to one year (p=0.0455). Conclusion: Polarized polychromatic light therapy in mild chronic generalized periodontitis improves microhemocirculation in periodontal tissues, increasing the efficacy of drug therapy.

Discovery of new AMR drugs targeting modulators of antimicrobial activity using in vivo silkworm screening systems.

Global concerns about drug-resistant bacteria have underscored the need for new antimicrobial drugs. Emerging strategies in drug discovery include considering the third factors that influence drug activity. These factors include host-derived elements, adjuvants, and drug combinations, which are crucial in regulating antimicrobial efficacy. Traditional in vivo assessments have relied on animal models to study drug absorption, distribution, metabolism, excretion, and toxicity (ADMET). Alternative models, such as silkworms, are being explored to overcome the ethical and financial barriers associated with mammalian models. The silkworm has been proven effective in evaluating ADMET and in highlighting the therapeutic potential enhanced by third factors. Host factors (either mammalian or non-mammalian) enhance the antimicrobial activity of antimicrobial agents such as lysocin E. Additionally, using D-cycloserine to potentiate vancomycin has successfully combated vancomycin-resistant infections in silkworms. Leveraging silkworms in drug discovery could establish a novel screening method incorporating interactions with third factors, whether host related or non-host-related, thus promising new pathways for identifying antimicrobial drugs with unique mechanisms of action.

An antimicrobial drug recommender system using MALDI-TOF MS and dual-branch neural networks.

Timely and effective use of antimicrobial drugs can improve patient outcomes, as well as help safeguard against resistance development. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently routinely used in clinical diagnostics for rapid species identification. Mining additional data from said spectra in the form of antimicrobial resistance (AMR) profiles is, therefore, highly promising. Such AMR profiles could serve as a drop-in solution for drastically improving treatment efficiency, effectiveness, and costs. This study endeavors to develop the first machine learning models capable of predicting AMR profiles for the whole repertoire of species and drugs encountered in clinical microbiology. The resulting models can be interpreted as drug recommender systems for infectious diseases. We find that our dual-branch method delivers considerably higher performance compared to previous approaches. In addition, experiments show that the models can be efficiently fine-tuned to data from other clinical laboratories. MALDI-TOF-based AMR recommender systems can, hence, greatly extend the value of MALDI-TOF MS for clinical diagnostics. All code supporting this study is distributed on PyPI and is packaged at https://github.com/gdewael/maldi-nn.

An antimicrobial drug recommender system using MALDI-TOF MS and dual-branch neural networks

Timely and effective use of antimicrobial drugs can improve patient outcomes, as well as help safeguard against resistance development. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently routinely used in clinical diagnostics for rapid species identification. Mining additional data from said spectra in the form of antimicrobial resistance (AMR) profiles is, therefore, highly promising. Such AMR profiles could serve as a drop-in solution for drastically improving treatment efficiency, effectiveness, and costs. This study endeavors to develop the first machine learning models capable of predicting AMR profiles for the whole repertoire of species and drugs encountered in clinical microbiology. The resulting models can be interpreted as drug recommender systems for infectious diseases. We find that our dual-branch method delivers considerably higher performance compared to previous approaches. In addition, experiments show that the models can be efficiently fine-tuned to data from other clinical laboratories. MALDI-TOF-based AMR recommender systems can, hence, greatly extend the value of MALDI-TOF MS for clinical diagnostics. All code supporting this study is distributed on PyPI and is packaged at https://github.com/gdewael/maldi-nn.

Recent advances in bioactive wound dressings.

Traditional wound dressings, despite their widespread use, face limitations, such as poor infection control and insufficient healing promotion. To address these challenges, bioactive materials have emerged as a promising solution in wound care. This comprehensive review explores the latest developments in wound healing technologies, starting with an overview of the importance of effective wound management, emphasising the need for advanced bioactive wound dressings. The review further explores various bioactive materials, defining their characteristics. It covers a wide range of natural and synthetic biopolymers used to develop bioactive wound dressings. Next, the paper discusses the incorporation of bioactive agents into wound dressings, including antimicrobial and anti-inflammatory agents, alongside regenerative components like growth factors, platelet-rich plasma, platelet-rich fibrin and stem cells. The review also covers fabrication techniques for bioactive wound dressings, highlighting techniques like electrospinning, which facilitated the production of nanofibre-based dressings with controlled porosity, the sol-gel method for developing bioactive glass-based dressings, and 3D bioprinting for customised, patient-specific dressings. The review concludes by addressing the challenges and future perspectives in bioactive wound dressing development. It includes regulatory considerations, clinical efficacy, patient care protocol integration and wound healing progress monitoring. Furthermore, the review considers emerging trends such as smart materials, sensors and personalised medicine approaches, offering insights into the future direction of bioactive wound dressing research.

A longitudinal point prevalence survey of antimicrobial use and resistance in tertiary care hospitals in Kerman: results from the national Iranian multicenter point prevalence survey of antimicrobials in 2021

BackgroundThe Global Point Prevalence Survey (PPS) of antimicrobial consumption and resistance has been widely undertaken to combat the global threat of antimicrobial resistance (AMR). This study was conducted in alignment with the Global-PPS in three tertiary care hospitals in Kerman, Iran, to evaluate antimicrobial consumption patterns.MethodsThe study was conducted from January 2020 to January 2021 in Afzalipour, Shafa, and Shahid Bahonar Hospitals. Data were collected using the standardized Global-PPS method at three different points throughout the year to minimize bias. Information on antimicrobial prescriptions, primary diagnosis, prophylaxis, therapy indications, and treatment type were documented. Antimicrobial prevalence was calculated using the total number of admitted patients as the denominator and those on antimicrobial regimens as the numerator.ResultsThe point prevalence of antimicrobial consumption in adult wards was 65.6% in Afzalipour Hospital, 42.3% in Shafa Hospital, and 78.7% in Bahonar Hospital. Non-penicillin beta-lactams, macrolides, lincosamides, and streptogramins were the most frequently prescribed antibiotic classes. Approximately 80% of prescriptions had explicit reasons documented, and targeted antibiotic therapy rates varied between 7.7% and 44.8% across hospitals.ConclusionsAntimicrobial consumption in Kerman’s tertiary care hospitals exceeded national and global levels, indicating an urgent need for interventions to promote rational antibiotic use. Infection control committees must implement rigorous monitoring measures to reduce antimicrobial resistance. Ongoing surveillance and targeted interventions are essential to curb the rising rates of antimicrobial resistance in the region.

Phytogenic Synthesis of Cuprous and Cupric Oxide Nanoparticles Using Black jack Leaf Extract: Antibacterial Effects and Their Computational Docking Insights.

Background: Green synthesized nanoparticles (NPs) have gained increasing popularity in recent times due to their broad spectrum of antimicrobial properties. This study aimed to develop a phytofabrication approach for producing cuprous (Cu2O) and cupric oxide (CuO) NPs using a simple, non-hazardous process and to examine their antimicrobial properties. Methods: The synthesis employed Bidens pilosa plant extract as a natural reducing and stabilizing agent, alongside copper chloride dihydrate as the precursor. The biosynthesized NPs were characterized through various techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Results: XRD analysis confirmed that the synthesized CuO and Cu2O NPs exhibited a high degree of crystallinity, with crystal structures corresponding to monoclinic and face-centered cubic systems. SEM images revealed that the NPs displayed distinct spherical and sponge-like morphologies. EDS analysis further validated the purity of the synthesized CuO NPs. The antimicrobial activity of the CuO and Cu2O NPs was tested against various pathogenic bacterial strains, including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Bacillus cereus, with the minimum inhibitory concentration (MIC) used to gauge their effectiveness. Conclusions: The results showed that the phytosynthesized NPs had promising antibacterial properties, particularly the Cu2O NPs, which, with a larger crystal size of 68.19 nm, demonstrated significant inhibitory effects across all tested bacterial species. These findings suggest the potential of CuO and Cu2O NPs as effective antimicrobial agents produced via green synthesis.

Formulation and Evaluation of the Antimicrobial Potential and Embryotoxicity of Betanin-Zinc Nanoparticles

Introduction: This study explores the green synthesis of betanin-based ZnO nanoparticles, with emphasis on their characterization, antimicrobial potential, and toxicity evaluation. Materials and methods: Zinc oxide nanoparticles (ZnO NPs) were produced using betanin isolated from Beta vulgaris, zinc hexahydrate, and 0.5M NaOH. To verify their structural and morphological characteristics, the produced betanin zinc oxide nanoparticles (BT-ZnO NPs) were examined using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, and Candida albicans were among the bacterial strains against which the antibacterial activity of these green-synthesised BT-ZnO NPs was assessed. Concurrently, zebrafish (Danio rerio) embryos were subjected to different amounts (10, 50, and 100 µg/mL) in order to perform embryotoxicity experiments. Results: SEM analysis showed that BT-ZnO NPs are irregularly shaped with a tendency to aggregate, which may enhance surface area. FTIR confirmed functional groups like phenols and amines, aiding nanoparticle stability. XRD indicated a composition of 52.5% crystalline and 47.5% amorphous content, supporting structural stability and bioactivity. Anti-microbial potential of BT-ZnO NPs shows notable inhibition at higher concentrations. In contrast, Candida albicans exhibited resistance to the nanoparticles. Embryotoxicity results showed that the ZnO NPs caused decreased survival rates, hatching delays, and morphological abnormalities in the zebrafish embryos, such as tail malformations and yolk sac oedema in the 100 µg/mL treatment group. Conclusion: While this study demonstrates the efficacy of BT-ZnO NPs as strong antimicrobial agents, it also emphasizes the need for caution regarding their environmental and health impacts, particularly at higher concentrations.

The Underrepresented Quinolinone Alkaloids in Genera Penicillium and Aspergillus: Structure, Biology, and Biosynthetic Machinery.

Quinolone alkaloids are N-heterocycles with extensive structural diversity, mainly derived from in fungi from anthranilic acid and amino acids as precursors with a wide range of biological activities as antifungal, antimicrobial, anti-inflammatory, and insecticidal activities. The quinolone basic skeleton comprised of either 2-quinolones or 4-quinolones generated more than one hundred compounds. Several reviews discussed quinolones; particularly, the fluoroquinolones, yet few studies tackled natural quinolones. Many of these quinolones were not assayed for their antimicrobial potential despite their unique stereospecificity, which can supersede synthetic quinolones if their discovery is coupled with OMICS techniques, biochemical and molecular strategies as heterologous expression to maximize their yield. Herein, we conducted a comprehensive review of the quinolone's family in Aspergillus and Penicillium species, the exclusive producers of quinolones whether they are soil, endophytic or marine derived highlighting their isolation, chemical structures, pharmacological effects, structure activity relationships if any, and biosynthetic machinery. We believe that our initiative will pave the way for further development of natural quinolones as future antimicrobial agents.

Helicobacter pylori Efflux Pumps: A Double-Edged Sword in Antibiotic Resistance and Biofilm Formation.

Helicobacter pylori is a major pathogen associated with various gastric diseases. Despite decades of research, the treatment of H. pylori remains challenging. One of the primary mechanisms contributing to failures of therapies targeting this bacterium is genetic mutations in drug target sites, although the growing body of scientific data highlights that efflux pumps may also take part in this process. Efflux pumps are proteinaceous transporters actively expelling antimicrobial agents from the interior of the targeted cells and reducing the intracellular concentration of these compounds. Considering that efflux pumps contribute to both antimicrobial resistance and biofilm formation, an in-depth understanding of their properties may constitute a cornerstone in the development of novel therapeutics against H. pylori. In line with this, the aim of the current review is to describe the multitude of efflux pumps produced by H. pylori and present the data describing the involvement of these proteins in tolerance and/or resistance to various classes of antimicrobial substances.

Risk Factors for Invasive Surgical Site Infections Among Adult Single Liver Transplant Recipients at Duke University Hospital in the Period 2015-2020.

Invasive primary surgical site infections (IP-SSI) are a severe complication of liver transplant surgery. Identification of risk factors for IP-SSI is critical to IP-SSI prevention. All adult single liver transplants performed at Duke University Hospital in the period 2015-2020 were reviewed for IP-SSI occurring within 90 d of transplant. Risks for IP-SSI were identified using least absolute shrinkage and selection operator variable selection procedure. A 2-sided P value of <0.05 was considered statistically significant. IP-SSI were identified in 34/470 (7.2%) adult single liver transplants. Repeat transplantation, spilt liver, Roux-en-Y biliary anastomosis, anastomotic leak, and post-transplant renal replacement therapy were positively associated with IP-SSI. IP-SSI were associated with increased length of index transplant hospitalization (24.5 versus 10.0 d, P < 0.01) and 1-y all-cause mortality (14.7% versus 4.1%, P = 0.02). Gram positive bacteria were the main pathogens (51.7%), followed by Gram negative bacteria (24.1%) and Candida (24.1%). Multidrug resistance bacteria increased over time (27.3% in 2015 versus 66.7% in 2020, P = 0.17). In the setting of routine antimicrobial prophylaxis and an overall low rate of IP-SSI, surgical factors were the main determinants of IP-SSI among adult liver transplant recipients. IP-SSI had a negative impact on the length of index transplant hospitalization and 1-y mortality. While the surgical factors associated with an increased risk of IP-SSI are not easily modifiable, their impact may be best contained by close clinical monitoring and tailored antimicrobial therapy.

Gene profile of virulence, antimicrobial resistance and action of enterocins in Campylobacter species isolated from broiler carcasses.

Campylobacteriosis is among the most reported zoonoses in the world, caused by species of Campylobacter, this disease is characterized by gastroenteritis in humans. The main species involved is Campylobacter jejuni, followed by Campylobacter coli. Contaminated chicken meat is often identified as an important source of infection related to human cases and Brazil is the largest exporter of chicken meat in the world, which makes the characterization of brazilian isolates crucial for the establishment of control measures. The objective was to evaluate the contamination of chilled and frozen carcasses sold in the Northeast of Brazil, by Campylobacter species, identify virulence genes, evaluate bacterial resistance to antibiotics and verify the antimicrobial action of the Crude Extract Containing Enterocins (CECE) produced by a probiotic strain of Enterococcus faecium. In this study, 12 chilled carcasses and 12 frozen carcasses were collected, sold retail in supermarkets. The following regions of the carcass were sampled: breast skin, wing skin, belly skin, neck skin, gizzard and liver. Samples of chicken carcasses were analyzed following ISO 10272-2 guidelines for the isolation of Campylobacter spp. The isolates were tested by PCR to identify genus, species C. jejuni, C. coli and C. lari and genes cdtA, cdtB, cdtC, sodB, dnaJ, cmeA, cmeB, cmeC. The assessment of susceptibility to antibiotics was carried out using the standard disk diffusion method and the antimicrobial activity of CECE was determined using the Minimum Inhibitory Concentration (MIC), the methodologies followed the recommendations and cutoff points according to EUCAST and CLSI. A total of 376 isolates of Campylobacter spp. were obtained, among these, 26 (7.0%) were positive for C. jejuni and no isolates were detected for C. coli and C. lari. The highest frequency of C. jejuni was obtained in chilled carcasses with 23 isolates (88.5%, p < 0.0001), in frozen carcasses three isolates were obtained (11.5%). The most frequency site of C. jejuni was the chest skin (7/27.0%), followed by skin of the wing (6/23.0%), skin of the cloaca (5/19.0%), gizzard (4/15.0%), skin of the neck (2/8.0%) and liver (2/8.0%), no significant differences were found between the sites sampled. The gene frequency was determined in: cdtA (3/11.5%), cdtB (3/11.5%), cdtC (5/19.0%), sodB (9/34.5%), dnaJ (3/11.5%), cmeA (4/15.0%), cmeB (4/15.0%) and cmeC (4/15.0%). The three efflux pump genes were amplified in four isolates (15.3%) and all tested genes were amplified in three isolates (11.5%). All C. jejuni isolates (26/100.0%) were found to be multiresistant to three or more classes of antimicrobials. The index of multiple resistance to antimicrobial drugs (IRMA) ranged from 0.4 to 1.0 among isolates of C. jejuni. The antimicrobial activity of CECE was able to inhibit at least 98.5% of the growth of all C. jejuni isolates. Therefore, chilled chicken carcasses present a greater risk of contamination than frozen carcasses, for this reason it is necessary to adopt practices that avoid cross-contamination during the preparation of chicken meat, in order to prevent campylobacteriosis. Furthermore, the presence of multiresistant and potentially virulent isolates highlights the need for further investigations to better understand the use of enterocins as alternative methods in the control of Campylobacter.

Antibiotic consumption patterns in older adults: a comparative study of people 65 years and older in and outside nursing homes, Belgium, 2016 to 2022.

BackgroundInappropriate antimicrobial consumption (AMC) drives the emergence of antimicrobial resistance. Institutionalised, older populations are associated with antimicrobial treatments of longer duration and broader spectrum than recommended, higher rates of multidrug-resistant infections and poorer outcomes for resistant infections. Yet systematic, national monitoring of AMC in nursing home (NH) residents is lacking.AimTo perform a retrospective analysis of antibiotic consumption in Belgian NHs, we compared analogous populations inside and outside NHs. We aimed to provide a blueprint for establishing surveillance of NH AMC, based on national reimbursement data.MethodsThe National Institute for Health and Disability Insurance supplied reimbursement AMC data for outpatients from 2016 to 2022. Data were classified by the Anatomical Therapeutic Chemical system, expressed as defined daily doses (DDD) and aggregated by prescription month, patient age, sex and residency inside/outside a NH. The number of ensured beneficiaries, aggregated by the same demographic variables, was collected from the Intermutualistic Agency. We compared the DDDs per 1,000 beneficiaries per day, along with secondary metrics for national and international targets for analogous populations inside and outside NHs.ResultsTotal antibiotic consumption decreased in both populations but remained twofold higher in NH residents. Proxy prescription quality metrics were consistently less favourable within NHs and diverged further during the COVID-19 pandemic. Distinct consumption patterns and greater seasonal fluctuations were observed in NH residents.ConclusionGiven the different infection risks and higher antibiotic consumption of NH residents, AMC surveillance and antimicrobial stewardship efforts targeting this fragile population are needed.

Distinction of clinical features and microbiological methods between Chlamydia psittaci and Legionella pneumophila pneumonia confirmed by metagenomic next-generation sequencing

Objectives Detection and diagnosis of Chlamydia psittaci (C. psittaci) pneumonia is often overlooked due to conventional methods limitations and similarity to other atypical community acquired pneumonia (CAP). Using mNGS, we aimed to distinguish psittacosis from legionellosis for early C. psittaci pneumonia diagnosis and better prognosis. Methods Thirty-seven patients diagnosed with atypical CAP were enrolled in this retrospective study, including 14 C. psittaci pneumonia and 23 Legionella pneumophila (L. pneumophila) pneumonia. We collected and compared baseline, lab results, radiology imaging, conventional microbiological methods and more importantly, mNGS results of clinical samples, as well as the treatments and prognosis between psittacosis and legionellosis. Results Patients with C. psittaci and L. pneumophila had similar symptoms and were presented with high levels of inflammatory markers. However, patients with C. psittaci pneumonia were more likely to have exposure to birds or parrots [11 (78.6%) vs. 2 (8.7%), p < 0.001], had higher proportions of fever and chill (p = 0.015 and 0.035), higher levels of hemoglobin and albumin (p = 0.002 and 0.018) compared with those with L. pneumophila. Of 14 C. psittaci patients, only one had positive IgM antibody, with no positive cultures. Early identification of pathogens by mNGS method contributed to timely antibiotics’ adjustment and better outcomes then, yet with similar hospital mortality between two groups [7.1% (1/14) vs. 34.8% (8/23), p = 0.112]. Conclusion Early mNGS detection of atypical pathogens in multiple samples improves on traditional methods, promptly adjust empirical antimicrobial treatment to pathogen-targeted antibiotics, further improve prognosis.

Green Synthesis of Silver Nanoparticles Using Doxycycline: Evaluation of Antimicrobial Potential and Organ-specific Toxicity

Silver nanoparticles (Ag-NPs) have wide applicability as antimicrobial, biomedical, and anti-cancer drug delivery systems. This study aimed to synthesize Ag-NPs using green methodology to assess their antimicrobial properties and toxicity. Ag-NPs were prepared using doxycycline, an antibiotic serving as a reducing and capping agent. The synthesized Ag-NPs were characterized by ultraviolet-visible spectrophotometry, X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectrometry. The antimicrobial efficacy of doxycycline-mediated Ag-NPs was assessed on Candida species in vitro and for toxicity in male albino mice in vivo. The Ag-NPs showed a surface plasmon resonance at 411 nm, indicating a 90 nm average size and spherical shape. Toxicity was tested on mouse organs (liver, kidney, spleen, heart and stomach) using three Ag-NP doses (50, 100, 200 mg/kg) over 14 days. The synthesized Ag-NPs produced large inhibition zones against two well-known fungal species, C. albicans and C. tropicalis, demonstrating their antimicrobial potential. The Ag-NPs showed varying degrees of toxicity in different mouse organs, depending on the administered dose, with more pronounced adverse effects observed at higher concentrations. Periodic administration of Ag-NPs at low-dose volumes holds promise as a safe approach to their use as antimicrobial agents. Low-dose Ag-NPs are minimally toxic and show strong antimicrobial efficacy.

The versatile NDI-based compounds: emerging anticancer and antimicrobial agents

The versatile NDI-based compounds: emerging anticancer and antimicrobial agents

Towards antimicrobial agents: Design and antibacterial activity of a hybrid fluorophore where porphyrin and Rose Bengal moieties are linked through the hydroxyl group of a xanthene dye

The axial complex of Sn(IV)-tetra(4-sulfophenyl)porphyrin (SnP) with Rose Bengal (RB) was obtained where RB axial binding is realized through the hydroxyl groups of the xanthene dye [SnP(RB)2]. The luminescent properties of the SnP(RB)2 (fluorescence and ability to generate singlet oxygen at room temperature) in aqueous media with additives of surfactant cetylpyridinium chloride (CPC) and ε-poly-l-lysine (EPL) were studied. It was found that nature of the medium (surfactant additives of different concentrations) determines the effectiveness of the photoinduced energy transfer from the RB fragment to the SnP fragment of the hybrid fluorophore (HF). It has been established that the ability of the HF to generate singlet oxygen in D2O and D2O-micellar media is higher than that of its constituent fragments. The dark and photodynamic antibacterial activity of the HF against two microorganisms [Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus)] was determined and analyzed. It was shown how the antibacterial activity of the HF depends on the nature of the bacteria, the micellar environment and radiation dose.