Common Agents Research Articles

Polyphenol-treatment without preceding glutaraldehyde fixation: a potential paradigm change for bioprosthetic heart valves

Abstract Background Glutaraldehyde (GA) is the common fixative agent for bioprosthetic heart valves (BHVs). However, its chemical instability can expose calcium binding sites and, at commercially used concentrations, GA does not ensure effective immunological tolerance, triggering an immune response correlated to degeneration. Recently, polyphenols (PPs) achieved an almost complete xenoantigens inactivation in GA-fixed BHVs ensuring chemical stability of the treated tissue while improving mechanical characteristics and adding anti-infective and anti-thrombotic properties [1-4]. Purpose A new PP-based treatment has been introduced as a potential GA substitute in BHV manufacturing. The unique chemical properties of PPs permit them to interact with the tissue through stable chemical bonds without depolymerization over time, achieving several improvements that promise to extend the long-term durability of BHVs (Fig.1). Methods The study compared the effects of two cross-linking methods on bovine pericardial tissue: (1) traditional fixation in GA, and (2) treatment with PPs without GA. The type of chemical interaction between PPs and tissue was evaluated through nuclear magnetic resonance. The xenoantigens inactivation was quantified in-vitro by ELISA test and in-vivo in a humanized mouse animal model. Biomechanical properties were assessed through uniaxial stress-strain tests and cross-link density through the shrinkage temperature test. The protective effect against bacterial adhesion was evaluated against a strain of S aureus, while the inhibition of thrombosis was evaluated in-vivo in a pig animal model and in-vitro in a blood-loop using bovine blood with radio-labeled platelets. Results PPs effectuated multiple chemical bonds with and within the pericardium including cross-links based on covalent and hydrogen bonds, stacking, and electrostatic interactions. The inactivation of over 90% of surface-xenoantigens of the treated tissue allowed for superior biocompatibility (compared to <50% by commercial GA concentrations). The increase in elongation exhibited by PP-treated tissue confirmed excellent biomechanical features (Fig.2) while a sufficient degree of cross-linking was demonstrated through an adequate shrinkage temperature. Furthermore, a significant degree of bacterial adhesion (86% inhibition evaluated with S. aureus) and thrombus formation (Fig.2, up to 90% inhibition) were observed. Conclusion There is a real clinical need for improved chemical stability, calcification resistance, and immunological tolerance of current BHVs (surgical and transcatheter). PP technology may substitute the use of GA extending their performance and durability, thereby opening trans-catheter heart valves to younger patients. Reducing the need for mechanical heart valves would also address the associated risks of lifelong anticoagulation therapy.Figure 1Figure 2

Epidemiological profile and mortality of infective endocarditis over the past decade: a systematic review and meta-analysis of 133 studies comprising 132,355 cases

Abstract Background Understanding the epidemiology of infective endocarditis (IE) is crucial in the context of an aging population, increased comorbidities, and the heightened occurrence of healthcare-associated cases. Comprehensive data on causative agents, affected valves, and associated mortality are essential for current clinical practice. Methods This systematic review was conducted according to the PRISMA guidelines. A random effects model meta-analysis was conducted. Eligible studies reporting outcomes on IE were identified through a search of the PubMed/Medline database from 2010 to 2021. Results One hundred-thirty-three studies with 132,584 patients from six continents were included in the analysis. The most common causative agents of IE were Staphylococci species in 36% of cases, followed by Streptococci species in 26% of cases and Enterococci species in 10% of cases. Of the studies providing further speciation, the predominant species was Staphylococcus aureus with an incidence of 29%, followed by Viridans Streptococcus with an incidence of 12%. We found an in-hospital/30-day mortality of 17% (CI: 16%-19%) from 109 studies worldwide. In the subgroup analysis, the highest mortality rates were observed in Latin America 33% (CI: 28%-38%) and Africa 25% (CI: 21%-30%), while the lowest mortality rates were reported in Oceania 13% (CI: 8%-19%), followed by North America 14% (CI: 11%-18%), Asia 15% (CI: 12%-18%), and Europe 17% (CI: 16%-19%). The aortic valve was affected in 46% of cases, followed by the mitral valve in 43%. Tricuspid valve IE and multivalvular IE were identified in 7% and 14% of the cases, respectively. Conclusion Our study highlights the shift in epidemiological profile of IE over the last decade with S. aureus identified as the most common causative microorganism of IE in almost one third of cases. IE remains a highly morbid and fatal condition with high mortality rates even in tertiary and high-expertise centers worldwide. While left-sided IE is by far more common, right-sided IE and multivalvular IE are not rare entities and should be considered early in the differential of patients presenting with suspected IE to decrease the risk of future complications.Global burden of infective endocarditis.

Fibroblast activation in cardio-oncology

Abstract Introduction Carcinoid heart disease is a rare disease affecting the right sided heart valves (1) while anthracycline cardiotoxicity is a dreaded sequelae of a common chemotherapeutic agent that can occur early or even years after exposure (2). Activated fibroblasts, a key factor in these diseases, can be imaged with 68Gallium-fibroblast activation protein inhibitor (68Ga-FAPI). Method 12 patients with carcinoid syndrome, 12 patients with previous anthracycline exposure and 10 healthy volunteers underwent hybrid 68Ga-FAPI positron emission tomography and magnetic resonance imaging. Areas of fibroblast activation were quantified as mean and maximum target-to-background ratios (TBRmean and TBRmax). Results Carcinoid syndrome: 2 of the 12 patients had carcinoid heart disease [mean age 70, 50% female] (CHD) (Figure 1A). 68Ga-FAPI uptake was seen in the liver lesions of all patients with known carcinoid liver tumours. Of the 10 patients without cardiac involvement, 6 had significant tricuspid valve 68Ga-FAPI uptake (CHD- FAPI+) (Figure 1B) and 4 did not (CHD- FAPI-). Median tricuspid TBRmax was significantly higher in CHD + [2.38 (IQR 2.35-2.42)], than CHD- patients [CHD- FAPI+: 1.68 (IQR 1.65-1.73), CHD- FAPI-: 1.55 (IQR 1.53-1.65)], although this was higher than healthy volunteers [1.45 (IQR 1.43- 1.61; p<0.05). CHD- FAPI+ patients had significantly elevated urinary 5-HIAA levels compared to CHD- FAPI- patients [Median =188 mg/24hr (IQR 151-196) in CHD- FAPI+ vs 32mg/24hr ( IQR 12-73); p=0.03]. Anthracycline chemotherapy: 3 of the 12 patients had cardiotoxicity [mean age 61, 67% female]. Anthracycline patients had higher left ventricular myocardial 68Ga-FAPI uptake than healthy volunteers with cardiotoxicity patients having the highest. [TBRmean: Cardiotoxicity 1.46 (IQR 1.36- 1.53), No cardiotoxicity 1.37 (IQR 1.19- 1.49), Healthy volunteers 0.73 (IQR 0.66 - 0.81); p<0.01 (Figure 1E). Across the cohort a moderate negative correlation was observed between Left ventricular ejection fraction and 68Ga-FAPI activity (LV TBRmean r =-0.46 and TBRmax (r= -0.66) Discussion 68 Ga-FAPI provides us the ability to assess fibroblast activation and for the first time demonstrated the key role of these cells in both these cardio-oncology conditions. Increased fibroblast activation is observed around the tricuspid valve in patients with carcinoid syndrome both in those with and without overt clinical disease. Similarly increased myocardial fibroblast activation is observed in patients exposed to anthracyclines even many years after exposure and where there is no overt evidence of cardiotoxicity. Conclusion 68Ga-FAPI imaging holds promise in evaluating the role of activated fibroblasts in the pathology of both carcinoid heart disease and cardiotoxicity, providing information beyond the current resolution of current clinical approaches.

Urogenital colonization and pathogenicity of E. Coli in the vaginal microbiota during pregnancy

This study explores the role of the vaginal microbiota (VM) in the pathophysiology of asymptomatic bacteriuria (ASB) in a cohort of 1,553 pregnant women. Worldwide, E. coli remains the most common etiological agent of bacteriuria during pregnancy and also a major causative agent of newborn infections. A healthy VM is typically characterized by low diversity and is dominated by lactic acid-producing species, notably those from the Lactobacillus genus. Our results point to decreases in Lactobacillus spp associated with an increase of gut-microbiota-associated species from the Enterobacterales order. Escherichia coli exhibited the most pronounced increase in abundance within the VM during bacteriuria and was notably associated with ASB. Molecular typing and antimicrobial resistance characterization of 72 metagenome assembled E. coli genomes (MAGs) from these pregnant women revealed a genomic signature of extraintestinal pathogenic E. coli (“ExPEC”) strains, which are involved in various extraintestinal infections such as urinary tract infections, newborn infections and bacteremia. Microbial diversity within the vaginal samples from which an E. coli MAG was obtained showed a substantial variation, primarily marked by a decrease in abundance of Lactobacillus species. Overall, our study shows how disruption in key bacterial group within the VM can disrupt its stability, potentially leading to the colonization by opportunistic pathogens.

Coxsackievirus B3-Induced m6A Modification of RNA Enhances Viral Replication via Suppression of YTHDF-Mediated Stress Granule Formation

N6-methyladenosine (m6A) is the most prevalent internal RNA modification. Here, we demonstrate that coxsackievirus B3 (CVB3), a common causative agent of viral myocarditis, induces m6A modification primarily at the stop codon and 3′ untranslated regions of its genome. As a positive-sense single-stranded RNA virus, CVB3 replicates exclusively in the cytoplasm through a cap-independent translation initiation mechanism. Our study shows that CVB3 modulates the expression and nucleo-cytoplasmic transport of the m6A machinery components—METTL3, ALKBH5 and YTHDFs—resulting in increased m6A modifications that enhance viral replication. Mechanistically, this enhancement is mediated through YTHDF-driven stress granule (SG) formation. We observed that YTHDF proteins co-localize with human antigen R (HuR), a protein facilitating cap-independent translation, in SGs during early infection. Later in infection, YTHDFs are cleaved, suppressing SG formation. Notably, for the first time, we identified that during early infection CVB3’s RNA-dependent RNA polymerase (3D) and double-stranded RNA (dsRNA) are stored in SGs, co-localizing with HuR. This early-stage sequestration likely protects viral components for use in late-phase replication, when SGs are disrupted due to YTHDF cleavage. In summary, our findings reveal that CVB3-induced m6A modifications enhance viral replication by regulating YTHDF-mediated SG dynamics. This study provides a potential therapeutic strategy for CVB3-induced myocarditis.

Imaging of Osteomyelitis

In this paper, an analysis of the demographic attributes, presenting symptoms, and infective agents, as well as the areas affected by skull osteomyelitis, of fifty male and fifty female patients is offered. A rough age estimate of around 61 years was found among the patients, with average symptom durations of about 6.8 months or longer. A significant percentage of diabetes (62%) and cranial nerve involvement (62%) were observed. The dominant symptom was headaches, representing 78% of cases, followed by cranial nerve palsy (62%) and hearing loss (48%). S. aureus was found to be the second most common causative agent, following only P. aeruginosa, which was the most common agent (54%). It became clear that there was a relevant infection in the temporomandibular joint and the retropharyngeal joint upon examining regional cases of the illness. In spite of therapy, only 38 percent of patients exhibited a cure, while 46 percent demonstrated improvement and 16 percent experienced a worsening of their condition.

Directional Transport in Hierarchically Aligned ZSM-5 Zeolites with High Catalytic Activity.

Zeolites, the most technically important crystalline microporous materials, are indispensable cornerstones of chemical engineering because of their remarkable catalytic properties and adsorption capabilities. Numerous studies have demonstrated that the hierarchical engineering of zeolites can maximize accessible active sites and improve mass transport, which significantly decreases the internal diffusion limits to achieve the desired performance. However, the construction of hierarchical zeolites with ordered alignments and size-controlled substructures in a convenient way is highly challenging. Herein, we develop a facile procedure using two common structure-directing agents, tetrapropylammonium hydroxide (TPAOH) and tetraethylammonium hydroxide (TEAOH), to synthesize hierarchically aligned ZSM-5 (Hie-ZSM-5) crystals with a-axis alignment substructures of controllable size. The control of the substructure size (α) in the range of 10-60 nm and the corresponding similarity (r = α/β, where β is the size of Hie-ZSM-5) ranging from 0.004 to 0.033 can be tuned by varying the Si/Al ratios (40-120). A systematic investigation of the overall crystallization process, using time-dependent XRD, SEM, TEM, and solid-state magic-angle spinning NMR (13C, 27Al, 29Si) methods, enable us to construct a solid mechanism for the generation of Hie-ZSM-5. Most importantly, directional transport in the unique structures of Hie-ZSM-5 efficiently enhances mass diffusion, as well as catalytic activity and stability. These findings improve our understanding of the zeolite crystallization process and inspire novel methods for the rational design of hierarchical zeolites.

Nitrogen fertilizers activate siderophore production by the common scab causative agent Streptomyces scabiei.

Streptomyces scabiei is the causative agents of common scab on root and tuber crops. Life in the soil imposes intense competition between soil-dwelling microorganisms and we evaluated here the antimicrobial properties of S. scabiei. Under laboratory culture conditions, increasing peptone levels correlated with increased growth inhibitory properties of S. scabiei. Comparative metabolomics showed that production of S. scabiei siderophores (desferrioxamines, pyochelin, scabichelin and turgichelin) increased with the quantity of peptone thereby suggesting that they participate in growth inhibition. Mass spectrometry imaging further confirmed that the zones of secreted siderophores and growth inhibition coincided. Moreover, either the repression of siderophore production or the neutralization of their iron-chelating activity both led to increased microbial growth. Replacement of peptone by natural nitrogen sources regularly used as fertilizers such as ammonium nitrate, ammonium sulfate, sodium nitrate, and urea also triggered siderophore production in S. scabiei. The observed effect is not mediated by alkalinization of the medium as increasing the pH without providing additional nitrogen sources did not induce siderophore production. The nitrogen-induced siderophore production also inhibited the growth of important plant pathogens. Overall, our work suggests that not only the iron availability but also the nitrogen fertilizer sources could significantly impact the competition for iron between crop-colonizing microorganisms.

Salvianolic acids modulate lifespan and gut microbiota composition in amyloid-β-expressing Drosophila melanogaster.

Alzheimer's disease (AD), a form of neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ), hyperphosphorylated Tau, and neuroinflammation. The increasing population affected by AD urges for the development of effective treatments. The correlation between AD and gut microbiome remains underexplored, potentially providing a better understanding of the disease. Salvianolic acid A (Sal A) and salvianolic acid B (Sal B) are the active components extracted from Salvia miltiorrhiza (Danshen), and their antioxidant, anti-inflammation and Aβ inhibition activities were shown previously. In this study, these compounds were used to investigate their effects on Aβ toxicity, using Drosophila melanogaster expressing human Aβ42 as the model organism, by examining their lifespan and changes in gut bacterial communities. The study used two batches of flies, reared on food with or without methylparaben (MP) supplementation to evaluate the influence of MP on this animal model during pharmacological studies. MP is a common antimicrobial agent used in flies' food. The treatment of Sal A prolonged the lifespan of Aβ-expressing flies reared on MP-supplemented food significantly (P < 0.001), but not those without MP. The lifespan of Sal B-treated flies did not show a significant difference compared to untreated flies for both groups reared on food with and without MP. Sal A-treated flies in the presence of MP exhibited a lower abundance of Corynebacterium and Enterococcus than the untreated flies, while Lactiplantibacillus was the most dominant taxa. Urea cycle was predicted to be predominant in this group compared to the untreated group. The control group, Aβ-expressing flies treated with Sal A and Sal B on MP-supplemented food had improved lifespan compared to their respective groups reared on food without MP, while untreated Aβ-expressing flies was the exception. The gut microbiota composition of flies reared on MP-supplemented food was also significantly different from those without MP (P < 0.001).

Trivalent outer membrane vesicles-based combination vaccine candidate induces protective immunity against Campylobacter and invasive non-typhoidal Salmonella in adult mice.

Campylobacter and invasive non-typhoidal Salmonella (iNTS) are among the most common causative agents of gastroenteritis worldwide. As of now, no single combination licensed vaccine is available for public health use against both iNTS and Campylobacter species. Outer-membrane vesicles (OMVs) are nanoscale proteoliposomes released from the surface of gram-negative bacteria during log phase and harbor a variety of immunogenic proteins. Based on epidemiology of infections, we formulated a novel trivalent outer membrane vesicles (TOMVs)-based vaccine candidate against Campylobacter jejuni (CJ), Salmonella Typhimurium (ST) and Salmonella Enteritidis (SE). Isolated OMVs from CJ, ST and SE were combined in equal ratios for formulation of TOMVs and 5µg of the developed vaccine candidate was used for intraperitoneal immunization of adult BALB/c mice. Immunization with TOMVs significantly activated both the humoral and cellular arm of adaptive immune response. Robust bactericidal effect was elicited by TOMVs immunized adult mice sera. TOMVs immunization induced long-term protective efficacy against CJ, ST and SE infections in mice. The study illustrates the ability of TOMVs-based combination immunogen in eliciting broad-spectrum protective immunity against prevalent Campylobacter and iNTS pathogens. According to the findings, TOMVs can work as a potent combination-based acellular vaccine candidate for amelioration of Campylobacter and iNTS-mediated gastroenteritis.

Pattern of Psychoactive Substance Use in Sierra Leone: A Descriptive Retrospective Study

Background Substance use, and pattern of consumption varies across population and may, within a particular population, show temporal variations in accordance with changing fads. Understanding the pattern of substance use in a population is key to any programme of demand reduction. Thus, we studied a consecutive series of patients with substance use disorders in our facility, aiming to determine the patient profile and pattern of substance use. Methods Hospital’s digital register was consulted and data of patients who were seen over a 16-months period, and who had diagnosis of ‘alcohol and substance use disorder’ were retrieved and analyzed. Results Seven hundred and nineteen patients were treated for substance use disorder over a 16-months period. Age of patients ranged from 16 to 69 years with mean age (SD) of 28.7(9.2) years. Majority were males (91%), single (87%) and had been to secondary or tertiary school with or without graduation. Fifty nine percent (421/719) of the patients admitted being on ‘Kush’, 49% on alcohol, 47% on cannabis, 11% on tramadol and 5.6% on cocaine. About 71% of the patients were poly-substance users while 29 percent were on one agent. Alcohol, ‘Kush’ and cannabis were the most common preferences of those who use more than one agent. Conclusions Substance use disorder in Freetown was most prevalent in young, adult, secondary school educated males. ‘Kush’ was the most common agent of abuse and frequency of polysubstance use is high. Understanding the factors responsible for low substance use among females in the population might point to some preventive control measures.

Common ownership and investor‐focused disclosure: Evidence from ESG financial materiality

AbstractIn this study, we investigate whether information demands made by common agents, specifically common institutional owners, drive firms to adopt a reporting framework that enhances the comparability and financial materiality of environmental, social, and governance information. Using a sample of 3659 unique US firms from 2015 to 2021, we collected data on the adoption of the Sustainability Accounting Standards Board's reporting framework—identifying first movers, followers, and non‐adopting firms—and their levels of common institutional ownership. Our results are robust across changes in the levels of common institutional ownership, various combinations of fixed effects, and the application of an instrumental variable approach. Our findings support the idea that investors' demand drives comparability and financial materiality in sustainability reporting and that common ownership enhances such disclosure by alleviating the concern over the proprietary costs of revealing sensitive information. Our study offers new insights into patterns of intra‐industry disclosure behavior and a better understanding of how a group of increasingly significant market participants (i.e., common institutional owners) influences firms' commitment to investor‐focused disclosure.

Meningitis after COVID-19 vaccination, a systematic review of case reports and case series

IntroductionVaccination is considered as one of the most promising strategies to overcome the COVID-19 pandemic. However, it could be associated with rare but serious complications. In the present study, we aimed to review the clinical course and etiology of post COVID-19 vaccination meningitis.MethodsAfter a systematic search in PubMed, Scopus, and Web of Sciences online databases as well as Google Scholar, documents were screened and qualified. Then data extraction was performed and the most frequent underlying agent of meningitis was found based on the reported cases.ResultsOverall, 35 cases of post COVID-19 vaccination meningitis from 33 articles were included in the review. Among them, 12 cases had proven viral diagnosis and 23 of them were reported to be vaccine-induced. The most frequent viral pathogen among the cases was VZV. The most prevalent symptom was headache, and the most common time of appearance symptoms was one week after vaccination.ConclusionOverall, our study suggested meningitis as a critical but not devastating complication of COVID-19 vaccination. Almost all patients responded well to common agents used to manage viral or vaccine-induced meningitis. It is recommended to monitor patients with a history of chickenpox after COVID-19 vaccination regarding the development of meningitis.

Clinical symptoms, comorbidities and health outcomes among outpatients infected with the common cold coronaviruses versus influenza virus

BackgroundCommon cold coronaviruses (ccCoVs) and influenza virus are common infectious agents causing upper respiratory tract infections (RTIs). However, clinical symptoms, comorbidities, and health effects of ccCoV infection remain understudied.MethodsA retrospective study evaluated 3,935 outpatients with acute upper RTI at a tertiary teaching hospital. The presence of ccCoV and influenza virus was determined by multiplex molecular assay. The demographic, clinical symptoms, and health outcomes were compared between patients with ccCoV (n = 205) and influenza (n = 417) infections. Multivariable logistic regression was employed to evaluate predictors and health outcomes over a one-year follow-up.ResultsSore throat, nasal discharge, headache, and myalgia were more predominant in ccCoV infection; fever was common in influenza. Most patients reported moderate symptoms severity (49.8% ccCoV, 56.1% influenza). Subsequent primary care visits with symptoms of RTI within a year were comparable for both infections (27.3% ccCoV vs. 27.6% influenza). However, patients with influenza reported increased primary care visits for non-RTI episodes and all-cause hospital admission. Baseline comorbidities were associated with increased primary care visits with symptoms of RTI in either ccCoV (adjusted odds ratio [aOR] 2.5; 95% confidence interval [CI] 1.1–5.9; P = 0.034) or influenza (OR 1.9; 95% CI 1.1–3.1; P = 0.017) infections, due probably to the dysregulation of the host immune response following acute infections. In patients infected with influenza infection, dyslipidemia was a predictor for subsequent primary care visits with symptoms of RTI (unadjusted OR 1.8; 95% CI 1.0–3.0; P = 0.040).ConclusionsBoth influenza and ccCoV infection pose significant disease burden, especially in patients with comorbidities. The management of comorbidities should be prioritized to mitigate poor health outcomes in infected individuals.

Common viral respiratory infections in children with cancer during the COVID-19 pandemic: a multicenter study from Türkiye.

Microbiologic confirmation of respiratory tract infections gained importance during the coronavirus disease 2019 (COVID-19) pandemic. This study retrospectively evaluated seasonal distribution, clinical presentation, and complications of respiratory viral infections (RVIs) other than COVID-19 in children with cancer during and after the pandemic lockdown. Two hundred and sixty-five inpatient and outpatient RVI episodes in 219 pediatric cancer patients confirmed by multiplex reverse transcriptase polymerase chain reaction (RT-PCR) panels from 13 centers were enrolled. Eighty-six (32.5%) of the total 265 episodes occurred in 16 months corresponding to the lockdowns in Türkiye, and the remaining 67.5% in 10 months thereafter. Human rhinovirus/enterovirus (hRE) (48.3%) was the most common agent detected during and after lockdown. Parainfluenza virus (PIV) (23.0%), influenza virus (9.8%), and respiratory syncytial virus (RSV) (9.1%) were the other common agents. The 28.7% of episodes were lower respiratory tract infections (LRTIs), and complications and mortality were higher than upper respiratory tract infections (URTIs) (25.0% vs 5.3%). Bacteremia was identified in 11.5% of culture-drawn episodes. Treatment delay in one-third and death within four weeks after RVI in 4.9% of episodes were observed. During the pandemic, fewer episodes of RVIs occurred during the lockdown period. Respiratory viruses may cause complications, delays in treatment, and even death in children with cancer. Therefore, increased awareness of RVIs and rapid detection of respiratory viruses will benefit the prevention and, in some cases, abrupt supportive and some antiviral treatment of RVI in children with cancer.

The development and evaluation of chitosan-coated enzyme magnetic nanoparticles for cellulose hydrolysis

The recycling capability, colloidal and thermal stability of exo-cellulase, endo-cellulase, and β-glucosidases with magnetic particles (MNPs) were evaluated. Co-precipitation and oxidation of Fe(OH)2 methods were used to fabricate magnetic nanoparticles. Three different enzymes were covalently bound to the surface of MNPs using 3-(aminopropyl) triethoxysilane (APTES) and a common protein crosslinking agent, glutaraldehyde. To evaluate the increase in colloidal dispersion stability, chitosan-coating was applied on MNPs and evaluated through particle settlement tests. The results showed that the chitosan-coated MNPs had 3.7 times higher colloidal dispersion stability than the bare MNPs. X-ray photoelectron spectroscopy (XPS) confirmed each magnetic nanoparticle surface modification step and successful enzyme binding. The optimum bioconjugate ratio in exo-cellulase, endo-cellulase, and β-glucosidases was evaluated, and having a high endo-cellulase bioconjugate in the reaction produced the highest glucose. The bioconjugates showed superior glucose productivity 39.4% at 65°C and 22.2% at 88°C in which the native enzyme is inactivated completely after 5 h of exposure. Recycling stability studies showed approximately 78% of activity was retained after 10 cycles and 32% of activity was retained after 20 cycles. The bioconjugates demonstrated equivalent total product conversions as a single reaction of an equivalent amount of the native enzyme after the 10th cycle this work introduces a novel method for covalently binding individual exo-cellulase, endo-cellulase, and β-glucosidases. These bioconjugates showed superior thermal stability and recyclability. It was also demonstrated that chitosan coating significantly improves the colloidal dispersion stability of bioconjugates. Thus this work validates the use of enzyme-MNP bioconjugates to effectively glucose production and promising technique for eventual continuous biological processes.

Ergosterol Biosynthesis and Regulation Impact the Antifungal Resistance and Virulence of Candida spp.

Ergosterol is a key fungal sterol that is mainly found in the plasma membrane and is responsible for the proper membrane structure, rigidity, permeability and activity of membrane proteins. Ergosterol plays a crucial role in the ability of fungi to adapt to environmental stresses. The biosynthesis of ergosterol is also intimately connected with the antifungal resistance and virulence of pathogenic fungi. The most common etiological agents of life-threatening fungal infections are yeasts belonging to the genus Candida. The antifungal agents mostly used to treat Candida spp. infections are azoles, which act as competitive inhibitors of sterol demethylase, a key enzyme in the fungal ergosterol biosynthetic pathway. Although most studies on ergosterol biosynthesis, its regulation and the uptake of sterols are from the baker’s yeast Saccharomyces cerevisiae, the study of ergosterol biosynthesis and its relationship to antifungal drug resistance and virulence in pathogenic fungi is of utmost importance. The increasing antifungal drug resistance of Candida spp. and the limited armamentarium of antimycotics pose a challenge in the development of new therapeutic approaches. This review summarizes the available data on ergosterol biosynthesis and related phenomena in Candida albicans and non-albicans Candida species (Candida glabrata, Candida parapsilosis, Candida tropicalis and Candida auris) with special emphasis on C. albicans and C. glabrata as the most common etiological agents of systemic candidiasis.

B-199 Rapid Molecular Detection of Meningitis Agents in Diverse Brazilian Regions (2019-2023): A Multicenter Study

Abstract Background Meningitis, caused by viral and bacterial agents, is a significant public health issue globally, with a substantial economic impact. In Brazil, the incidence of meningitis varies by region, making the identification of the causative agent crucial for effective treatment. This study aims to evaluate the epidemiology of meningitis agents diagnosed using a rapid molecular detection panel in samples from various hospital units of a nationwide diagnostic and healthcare company. Methods Samples from several hospitals across different regions of Brazil were analyzed using the FilmArray® rapid molecular panel for meningitis and encephalitis, capable of identifying up to 14 agents, including bacteria, viruses, and fungi/yeasts. Gender, age group, regional distribution, and agent prevalence from January 2019 to April 2023, were retrieved from the database ensuring compliance with the Brazilian Data Privacy and Protection (LGPD) and local Research Ethics Committee guidelines. Results The study included 485 patients from 41 cities across 11 Brazilian states. The age range was 0 to 96 years, with an average age of 45 years, and a majority of female participants (59%). The highest number of test requests occurred in 2022 (17.5%), followed by 2021 (10%), with 2019, 2020, and 2023 accounting for less than 5% of requests each. The overall positivity rate was 10.5% (51/485), with 92.8% (13/14) of the possible agents identified. Viral agents were detected in 60.7% of positive cases, bacterial agents in 39.2%, and one mixed infection (human herpesvirus 6 and Escherichia coli K1) in a 2-year-old child. No fungal/yeast infections were detected. The most common agents were varicella-zoster virus (18.2%), Haemophilus influenzae (12.7%), herpes simplex viruses type 1 and 2 (12.7% each), and enterovirus (12.7%). Conclusions The study highlights the importance of rapid molecular diagnostic methods in Brazilian clinical-laboratory practice, offering fast, safe, and sensitive detection of meningitis-causing agents, which can contribute to improved patient outcomes.

Application of questionnaires in studying the frequency of multiple chemical sensitivity syndrome

BACKGROUND: Multiple chemical sensitivity syndrome is a set of adverse physiological reactions of the human body to exposure to common chemical agents in low doses, which are considered non-toxic to the population. AIM: To study the frequency and characteristics of multiple chemical sensitivity syndrome manifestation using the Russified questionnaire Quick Environment Exposure and Sensitivity Inventory (QEESI). MATERIAL AND METHODS: In the pilot study, 468 people undergoing a preventive medical examination were surveyed (232 men, average age 34.2±9.3 years, and 236 women, average age 42.9±13.8 years). To assess multiple chemical sensitivity, an analysis of three subscales of the Russified validated QEESI questionnaire (chemical intolerance, severity of symptoms, and impact on everyday life) was used. The statistical significance of differences in relative indicators was assessed using the Pearson χ2 criterion. Absolute indicators were presented as M (SD). Relationships and differences in indicators were considered statistically significant at p 0.05. RESULTS: The frequency of multiple chemical sensitivity syndrome was 45.5%, 51.7% of patients had concomitant diseases. The frequency of comorbidities with and without multiple chemical sensitivity syndrome was comparable: allergic diseases — 25.6 vs 17.5%, χ2=3.84, p=0.069; irritable bowel syndrome — 8.1 vs 10.9%, χ2=3.648, p=0.057; migraine — 11 vs 10.5%, χ2=0.642, p=0.424. Multiple chemical sensitivity syndrome was more often detected in women (74.3 vs 25.6%, χ2=5.76, p=0.001) and patients with a sedentary lifestyle (58.3 vs 24.8% χ2=11.9; p=0.01). In patients with multiple chemical sensitivity syndrome, the most common central nervous system complaints were mood lability (26.5 vs 11.3%, χ2=18.936, p=0.003), headaches (27.4 vs 10.5%, χ2=7.555, p=0.006); in the gastrointestinal tract — nausea (13.7 vs 7.6%, χ2=4.826, p=0.029), abdominal pain (10.9 vs 5.5%, χ2=4.178, p=0.041). CONCLUSION: A high frequency of multiple chemical sensitivity syndrome (45.5%) was revealed, which was typical for women and patients with a sedentary lifestyle. Patients with this syndrome significantly more often reported complaints from the central nervous system and gastrointestinal tract.

A-280 The Good, the Bad, and the Downright Inappropriate reporting of Gram Positive Resistance Genes in a Proficiency Testing Program

Abstract Background Molecular technologies can rapidly identify the pathogen, allowing for the correct antimicrobial agent to be used for initial treatment. Many laboratories have implemented molecular technologies to identify the causative agents of infections from various bodily sources. Screening for potential resistance genes to common antimicrobial agents provides high value to clinicians to help guide optimal antimicrobial therapy selection. CLIA ‘88 required proficiency testing for physician office laboratories in 1994. This was in addition to the requirement for hospital and reference laboratories instituted under CLIA ‘67. This study compares the accuracy of laboratory performance for molecular multiplex platforms in the detection of Gram positive resistance genes from gold standard qualified samples in a novel proficiency program. Methods American Proficiency Institute, an independent proficiency testing provider, reviewed the reporting of various molecular multiplex systems against simulated patient samples in proficiency samples offered in 2023. Participants were instructed to only report resistance genes their systems were capable of testing for, and ensure they were appropriate for the organism recovered. Failure rates for participants were evaluated against an 80% participant consensus standard for detection of resistance genes. Results During the 2023 proficiency year, Gram positive targets were included 14 times in 4 different multiplex programs. Accuracy for correct reporting of resistance genes appropriate for the organism recovered ranged between 71.0%- 100%. Conversely, the number of laboratories reporting resistance genes that were inappropriate for the organism recovered ranged between 2.0% - 67.0%. Conclusions Based on the results reported by participants in API’s proficiency event, Molecular Multiplex platforms are accurately identifying Gram positive resistance genes. However, many participants using both FDA approved and LDT systems reported results for resistance genes that were not applicable for the organism recovered. This inaccurate reporting could potentially lead to inappropriate antimicrobial therapies being prescribed.