The Reduction of SARS-CoV-2 RNA Concentration in the Presence of Sewer Biofilms

Wastewater surveillance has been widely used to track the prevalence of SARS-CoV-2 in communities. Although some studies have investigated the decay of SARS-CoV-2 RNA in wastewater, understanding about its fate during wastewater transport in real sewers is still limited. This study aims to assess the impact of sewer biofilms on the dynamics of SARS-CoV-2 RNA concentration in naturally contaminated real wastewater (raw influent wastewater without extra SARS-CoV-2 virus/gene seeding) using a simulated laboratory-scale sewer system. The results indicated that, with the sewer biofilms, a 90% concentration reduction of the SARS-CoV-2 RNA was observed within 2 h both in wastewater of gravity (GS, gravity-driven sewers) and rising main (RM, pressurized sewers) sewer reactors. In contrast, the 90% reduction time was 8–26 h in control reactors without biofilms. The concentration reduction of SARS-CoV-2 RNA in wastewater was significantly more in the presence of sewer biofilms. In addition, an accumulation of c.a. 260 and 110 genome copies/cm2 of the SARS-CoV-2 E gene was observed in the sewer biofilm samples from RM and GS reactors within 12 h, respectively. These results confirmed that the in-sewer concentration reduction of SARS-CoV-2 RNA in wastewater was likely caused by the partition to sewer biofilms. The need to investigate the in-sewer dynamic of SARS-CoV-2 RNA, such as the variation of RNA concentration in influent wastewater caused by biofilm attachment and detachment, was highlighted by the significantly enhanced reduction rate of SARS-CoV-2 RNA in wastewater of sewer biofilm reactors and the accumulation of SARS-CoV-2 RNA in sewer biofilms. Further research should be conducted to investigate the in-sewer transportation of SARS-CoV-2 and their RNA and evaluate the role of sewer biofilms in leading to underestimates of COVID-19 prevalence in communities.

Escherichia coli ST2797 Is Abundant in Wastewater and Might Be a Novel Emerging Extended-Spectrum Beta-Lactamase E. coli.

The increasing prevalence of antibiotic-resistant bacteria is an emerging threat to global health. The analysis of antibiotic-resistant enterobacteria in wastewater can indicate the prevalence and spread of certain clonal groups of multiresistant bacteria. In a previous study of Escherichia coli that were isolated from a pump station in Norway over 15 months, we found a recurring E. coli clone that was resistant to trimethoprim, ampicillin, and tetracycline in 201 of 3,123 analyzed isolates (6.1%). 11 representative isolates were subjected to whole-genome sequencing and were found to belong to the MLST ST2797 E. coli clone with plasmids carrying resistance genes, including blaTEM-1B, sul2, dfrA7, and tetB. A phenotypic comparison of the ST2797 isolates with the uropathogenic ST131 and ST648 that were repeatedly identified in the same wastewater samples revealed that the ST2797 isolates exhibited a comparable capacity for temporal survival in wastewater, greater biofilm formation, and similar potential for the colonization of mammalian epithelial cells. ST2797 has been isolated from humans and has been found to carry extended spectrum ß-lactamase (ESBL) genes in other studies, suggesting that this clonal type is an emerging ESBL E. coli. Collectively, these findings show that ST2797 was more ubiquitous in the studied wastewater than were the infamous ST131 and ST648 and that ST2797 may have similar abilities to survive in the environment and cause infections in humans. IMPORTANCE The incidence of drug-resistant bacteria found in the environment is increasing together with the levels of antibiotic-resistant bacteria that cause infections. The COVID-19 pandemic has shed new light on the importance of monitoring emerging threats and finding early warning systems. Therefore, to mitigate the antimicrobial resistance burden, the monitoring and early identification of antibiotic-resistant bacteria in hot spots, such as wastewater treatment plants, are required to combat the occurrence and spread of antibiotic-resistant bacteria. Here, we applied a PhenePlate system as a phenotypic screening method for genomic surveillance and discovered a dominant and persistent E. coli clone ST2797 with a multidrug resistance pattern and equivalent phenotypic characteristics to those of the major pandemic lineages, namely, ST131 and ST648, which frequently carry ESBL genes. This study highlights the continuous surveillance and report of multidrug resistant bacteria with the potential to spread in One Health settings.

Antimicrobial Peptides: Challenging Journey to the Pharmaceutical, Biomedical, and Cosmeceutical Use.

Antimicrobial peptides (AMPs), or host defence peptides, are short proteins in various life forms. Here we discuss AMPs, which may become a promising substitute or adjuvant in pharmaceutical, biomedical, and cosmeceutical uses. Their pharmacological potential has been investigated intensively, especially as antibacterial and antifungal drugs and as promising antiviral and anticancer agents. AMPs exhibit many properties, and some of these have attracted the attention of the cosmetic industry. AMPs are being developed as novel antibiotics to combat multidrug-resistant pathogens and as potential treatments for various diseases, including cancer, inflammatory disorders, and viral infections. In biomedicine, AMPs are being developed as wound-healing agents because they promote cell growth and tissue repair. The immunomodulatory effects of AMPs could be helpful in the treatment of autoimmune diseases. In the cosmeceutical industry, AMPs are being investigated as potential ingredients in skincare products due to their antioxidant properties (anti-ageing effects) and antibacterial activity, which allows the killing of bacteria that contribute to acne and other skin conditions. The promising benefits of AMPs make them a thrilling area of research, and studies are underway to overcome obstacles and fully harness their therapeutic potential. This review presents the structure, mechanisms of action, possible applications, production methods, and market for AMPs.

Exploring the intersection of Aspergillus fumigatus biofilms, infections, immune response and antifungal resistance.

Aspergillus fumigatus is an opportunistic pathogen that primarily affects the lungs and frequently elicits an allergic immune response in human hosts via inhalation of its airborne asexual spores (conidia). In immunocompromised individuals, the conidia of this fungus can germinate in the lung and result in severe systemic infections characterised by widespread tissue and organ damage. Conversely, in healthy hosts, the innate immune system is instrumental in eliminating the conidia and preventing disease progression. As with numerous other pathogenic fungi, A. fumigatus possesses a set of virulence factors that facilitate its infective mechanism and the circumvention of immune defences in susceptible hosts. The intrinsic capacity of A. fumigatus to form complex 3D-structured biofilms, both on biotic and abiotic surfaces, represents a key determinant of its evasion of the host immune system and resistance to antifungal drugs. This review delineates the pivotal role of A. fumigatus biofilm structure and function as a significant virulence factor in pathogenic infections, such as aspergilloma and invasive pulmonary aspergillosis (IPA). Additionally, we discuss the importance for the development of novel antifungal drugs as drug-resistant strains continue to evolve. Furthermore, co-infections of A. fumigatus with other nosocomial pathogens have a substantial impact on patient's health outcomes. In this context, we provide a brief overview of COVID-19-associated pulmonary aspergillosis (CAPA), a recently documented condition that has gained attention due to its associated high degree of severity.

Antifungal Activity and Potential Action Mechanism of Allicin against Trichosporon asahii.

Trichosporon asahii is an emerging opportunistic pathogen that causes potentially fatal disseminated trichosporonosis. The global prevalence of coronavirus disease 2019 (COVID-19) poses an increasing fungal infection burden caused by T. asahii. Allicin is the main biologically active component with broad-spectrum antimicrobial activity in garlic. In this study, we performed an in-depth analysis of the antifungal characteristics of allicin against T. asahii based on physiological, cytological, and transcriptomic assessments. In vitro, allicin inhibited the growth of T. asahii planktonic cells and biofilm cells significantly. In vivo, allicin improved the mean survival time of mice with systemic trichosporonosis and reduced tissue fungal burden. Electron microscopy observations clearly demonstrated damage to T. asahii cell morphology and ultrastructure caused by allicin. Furthermore, allicin increased intracellular reactive oxygen species (ROS) accumulation, leading to oxidative stress damage in T. asahii cells. Transcriptome analysis showed that allicin treatment disturbed the biosynthesis of cell membrane and cell wall, glucose catabolism, and oxidative stress. The overexpression of multiple antioxidant enzymes and transporters may also place an additional burden on cells, causing them to collapse. Our findings shed new light on the potential of allicin as an alternative treatment strategy for trichosporonosis. IMPORTANCE Systemic infection caused by T. asahii has recently been recognized as an important cause of mortality in hospitalized COVID-19 patients. Invasive trichosporonosis remains a significant challenge for clinicians, due to the limited therapeutic options. The present work suggests that allicin holds great potential as a therapeutic candidate for T. asahii infection. Allicin demonstrated potent in vitro antifungal activity and potential in vivo protective effects. In addition, transcriptome sequencing provided valuable insights into the antifungal effects of allicin.

Advanced Nitric Oxide Generating Nanomedicine for Therapeutic Applications.

Nitric oxide (NO), a gaseous transmitter extensively present in the human body, regulates vascular relaxation, immune response, inflammation, neurotransmission, and other crucial functions. Nitrite donors have been used clinically to treat angina, heart failure, pulmonary hypertension, and erectile dysfunction. Based on NO's vast biological functions, it further can treat tumors, bacteria/biofilms and other infections, wound healing, eye diseases, and osteoporosis. However, delivering NO is challenging due to uncontrolled blood circulation release and a half-life of under five seconds. With advanced biotechnology and the development of nanomedicine, NO donors packaged with multifunctional nanocarriers by physically embedding or chemically conjugating have been reported to show improved therapeutic efficacy and reduced side effects. Herein, we review and discuss recent applications of NO nanomedicines, their therapeutic mechanisms, and the challenges of NO nanomedicines for future scientific studies and clinical applications. As NO enables the inhibition of the replication of DNA and RNA in infectious microbes, including COVID-19 coronaviruses and malaria parasites, we highlight the potential of NO nanomedicines for antipandemic efforts. This review aims to provide deep insights and practical hints into design strategies and applications of NO nanomedicines.

From Biowaste to Lab-Bench: Low-Cost Magnetic Iron Oxide Nanoparticles for RNA Extraction and SARS-CoV-2 Diagnostics.

The gold standard for diagnostics of SARS-CoV-2 (COVID-19) virus is based on real-time polymerase chain reaction (RT-PCR) using centralized PCR facilities and commercial viral RNA extraction kits. One of the key components of these kits are magnetic beads composed of silica coated magnetic iron oxide (Fe2O3 or Fe3O4) nanoparticles, needed for the selective extraction of RNA. At the beginning of the pandemic in 2019, due to a high demand across the world there were severe shortages of many reagents and consumables, including these magnetic beads required for testing for SARS-CoV-2. Laboratories needed to source these products elsewhere, preferably at a comparable or lower cost. Here, we describe the development of a simple, low-cost and scalable preparation of magnetic nanoparticles (MNPs) from biowaste and demonstrate their successful application in viral RNA extraction and the detection of COVID-19. These MNPs have a unique nanoplatelet shape with a high surface area, which are beneficial features, expected to provide improved RNA adsorption, better dispersion and processing ability compared with commercial spherical magnetic beads. Their performance in COVID-19 RNA extraction was evaluated in comparison with commercial magnetic beads and the results presented here showed comparable results for high throughput PCR analysis. The presented magnetic nanoplatelets generated from biomass waste are safe, low-cost, simple to produce in large scale and could provide a significantly reduced cost of nucleic acid extraction for SARS-CoV-2 and other DNA and RNA viruses.

The Relationship between Wearing Protective Masks and Poor Oral Health

Since the beginning of the COVID-19 pandemic, the number of people wearing masks in everyday life has increased. At the same time, there has been a noticeable rise in the amount of patients with bad breath (foe-tor ex ore), gingivitis, caries, and xerostomia. The appearance of these symptoms and diseases caused by wearing a mask is designated by the term mask mouth. The aim of this article is to establish the link between wearing protective masks and deteriorating oral health. From the conducted research, it has been es-tablished that wearing a surgical mask over a long period of time leads to reduced air exchange in the mask and "recycling" of exhaled air. This leads to inhalation of air with increased CO2 content and increase in pCO2 in the blood, which is subsequently compensated by rapid and deep breathing in most cases through the mouth. The goal is to exhale the accumulated CO2. As the mask reduces air exchange, the level of CO2 in the mask remains relatively high. Prolonged breathing through the mouth often leads to xerostomia. Saliva is known to have protective functions against the development of bacteria in the oral cavity through its an-tibacterial properties. Xerostomia can be a prerequisite for the development of various diseases of bacterial origin, such as gingivitis. Furthermore, oral respiration leads to an increase in temperature and CO2 in the air in the mask and a decrease in pH in the oral cavity, which are optimal conditions for biofilm formation, plaque buildup, development of most bacteria, e.g., S. mutans, which is the main cause of caries.Copyright © 2022, Bulgarian-American Center. All rights reserved.

A review on antimicrobial mechanism and applications of graphene-based materials.

In recent years, graphene and its derivatives, owing to their phenomenal surface, and mechanical, electrical, and chemical properties, have emerged as advantageous materials, especially in terms of their potential for antimicrobial applications. Particularly important among graphene's derivatives is graphene oxide (GO) due to the ease with which its surface can be modified, as well as the oxidative and membrane stress that it exerts on microbes. This review encapsulates all aspects regarding the functionalization of graphene-based materials (GBMs) into composites that are highly potent against bacterial, viral, and fungal activities. Governing factors, such as lateral size (LS), number of graphene layers, solvent and GBMs' concentration, microbial shape and size, aggregation ability of GBMs, and especially the mechanisms of interaction between composites and microbes are discussed in detail. The current and potential applications of these antimicrobial materials, especially in dentistry, osseointegration, and food packaging, have been described. This knowledge can further drive research that aims to look for the most suitable components for antimicrobial composites. The need for antimicrobial materials has seldom been more felt than during the COVID-19 pandemic, which has also been highlighted here. Possible future research areas include the exploration of GBMs' ability against algae.

Characterization of the Oral Microbiome in Wearers of Fixed and Removable Implant or Non-Implant-Supported Prostheses in Healthy and Pathological Oral Conditions: A Narrative Review.

Oral commensal microorganisms perform very important functions such as contributing to the health of the host. However, the oral microbiota also plays an important role in the pathogenesis and development of various oral and systemic diseases. The oral microbiome may be characterized by a higher prevalence of some microorganisms than others in subjects with removable or fixed prostheses, depending on oral health conditions, the prosthetic materials used, and any pathological conditions brought about by inadequate prosthetic manufacturing or poor oral hygiene. Both biotic and abiotic surfaces of removable and fixed prostheses can be easily colonized by bacteria, fungi, and viruses, which can become potential pathogens. The oral hygiene of denture wearers is often inadequate, and this can promote oral dysbiosis and the switch of microorganisms from commensal to pathogens. In light of what emerged from this review, fixed and removable dental prostheses on teeth and on implants are subject to bacterial colonization and can contribute to the formation of bacterial plaque. It is of fundamental importance to carry out the daily hygiene procedures of prosthetic products, to design the prosthesis to facilitate the patient's home oral hygiene practices, and to use products against plaque accumulation or capable of reducing oral dysbiosis to improve patients' home oral practices. Therefore, this review primarily aimed to analyze the oral microbiome composition in fixed and removable implant or non-implant-supported prostheses wearers in healthy and pathological oral conditions. Secondly, this review aims to point out related periodontal self-care recommendations for oral dysbiosis prevention and periodontal health maintenance in fixed and removable implant or non-implant-supported prostheses wearers.

Peculiarities of Periodontal Pocket Microbiome in Patients with Generalized Periodontitis in the Post-Covid Period

The oral cavity, like the lungs, is often referred to as the <<ecological niche of commensal, symbiotic, and pathogenic or-ganisms,>> and the emigration and elimination of microbes between them are constant, ensuring a healthy distribution of saprophytic microorganisms that maintains organ, tissue, and immune homeostasis. The prolonged hospital stays due to COVID-19 complications, cross-infection, oxygenation therapy through the mask or incubation, and long-term intravenous infusions limit the patient's ability to care about the oral cavity, regularly clean teeth, floss interdental, etc., which creates extremely favorable conditions for colonization by aerobic and anaerobic pathogens of the oral cavity and periodontal pockets and leads to the rapid progression of chronic generalized periodontitis in this category of patients in the future. The goal of the study was to assess the state of the microbiome of the periodontal pockets of dental patients in the post-covid period. Methods. The object of the study was 140 patients with generalized periodontitis of the I and II stages of development in the chronic course (GP), among which 80 patients had coronavirus disease in the closest past. The patients were randomized by age, sex, and stage of GP development. The diagnosis of periodontal disease was established according to the classification by Danilevskyi. The bacteriological material for aerobic and facultative anaerobic microflora and yeast-like fungi was collected from periodontal pockets with a calibrated bacteriological loop and immediately seeded on blood agar. Results. Significant qualitative and quantitative changes in the nature of the oral microbiocenosis were observed in patients with GP after the recent coronavirus disease, compared with similar patients who did not suffer from COVID-19. We have noticed almost complete disappearance of bacteria that belong to the transient representatives of the oral microflora such as Neisseria, corynebacteria (diphtheria), micrococci, and lac-tobacilli. The main resident representatives of the oral microflora, i.e., alpha-hemolytic Streptococci of the mitis group, were found in all healthy individuals and patients of groups A and C, but in 30.0 +/- 4.58% of patients in group B, alpha-hemolytic streptococci in the contents of periodontal pockets are present in quantities not available for detection by the applied method (<2.7 lg CCU/mL). In terms of species, Streptococcus oralis and Streptococcus salivarius are more characteris-tic in gingival crevicular fluid in healthy individuals (93.8% of selected strains). In 68.4 +/- 3.32% of patients in group A, 64.0 +/- 3.43% of patients in group B, and 67.5 +/- 3.76% of patients in group C, the dominant species were Streptococcus gordonii and Streptococcus sanguinis (p<0.01), which increased pathogenic potential as they produce streptolysin-O, inhibit complement activation, bind to fibronectine, actively form biofilms on the surface of tooth enamel and gum epithelial surface, and can act as an initiator of adhesion of periodontal pathogens. The other representatives of the resident microflora of the oral cavity - Stomatococcus mucilaginosus and Veillonella parvula for the patients of group C are also found in periodontal pockets with a significantly lower index of persistence and minimal population level. In the post-covid period, both the population level and the frequency of colonization of periodontal pockets by Staphylo-cocci and beta-hemolytic Streptococci decreases rapidly. For these patient groups, unlike for those that did not suffer from COVID-19, we did not find any case of colonization with Staphylococcus aureus, as well as beta-hemolytic Streptococci and Epidermal staphylococcus were also absent. The most characteristic in the post-covid period is a decrease in the proportion of alpha-hemolytic Streptococci, an increase in the proportion of yeast-like fungi of Candida species, as well as the appearance of a significant number of gram-negative rod-shaped bacteria (Enterobacteria and Pseudomonads). In periodontal patien s, the microbial count is approximately 2 orders of magnitude lower than in those with GP who did not suffer from COVID-19 (p<0.05). Conclusions. The overpassed coronavirus disease due to intensive antibiotic therapy leads to a marked decrease in the number of viable saprophytic microorganisms in the periodontal pockets of patients with GP. In the post-covid period for the patients with GP, there is a decrease in the level of colonization of periodontal pockets by species of resident oral microflora - alpha-hemolytic Streptococci, reduction of resident micro-organism's species, and almost complete disappearance of transient microflora. On the other hand, the frequency of colonization of periodontal pockets by fungi species, enterobacteria, and pseudomonads significantly increases. There are more expressed disorders in the periodontal pocket's microbiome for the patients with a severe and complicated course of coronavirus disease, such as post-covid pulmonary fibrosis, which requires reconsideration of approaches to therapeutic and pharmacological treatment in this category of patients.Copyright © 2022, Zabolotny Institute of Microbiology and Virology, NAS of Ukraine. All rights reserved.

Gut microbiome and COVID-19

Coronavirus disease 2019 (COVID-19) caused by the enveloped double-stranded positive sense RNA virus, SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is responsible for one of the most significant and widespread global pandemic in recent times. It started in China in December 2019 and rapidly spread to each and every country of the world and caused more 521 million infections and more than 6.28 million deaths (as of May 17, 2022) and counting. It primarily infects the respiratory tract, but direct infection thorough other routes (ocular and gastrointestinal) is also reported. The virus can spread easily to different body systems causing multisystemic diseases leading to significant morbidity and mortality. Human gut microbiome is the most complex ecological niche in nature and harbors trillions of microorganisms, predominantly bacteria and viruses. Gut microbiome exists in homeostatic, mutually beneficial, equilibrium with the host in healthy humans. However, any shift in balance towards dysbiosis (unhealthy gut microbiome) due to different factors (such as unhealthy diet, antibiotic use, disease) that modulate microbiome may lead to a variety of diseases and health conditions. Recent studies are demonstrating that SARS-CoV-2 infection modulate gut microbiome and gut microbiome can also influence severity of COVID-19. In this review, we summarize our knowledge with focus on the emerging theme of bidirectional cross-talk between gut microbiome and SARS-CoV-2, an important component in formulating strategies to control this formidable virus. © 2023 Elsevier Inc. All rights reserved.

Nanotheranostics to target antibiotic-resistant bacteria: Strategies and applications

Various health agencies, such as the European Medical Agency (EMA), Centers for Disease Control and Prevention (CDC), and World Health Organization (WHO), timely cited the upsurge of antibiotic resistance as a severe threat to the public health and global economy. Importantly, there is a rise in nosocomial infections among covid-19 patients and in-hospitalized patients with the delineating disorder. Most of nosocomial infections are related to the bacteria residing in biofilm, which are commonly formed on material surfaces. In biofilms, microcolonies of various bacteria live in syntropy;therefore, their infections require a higher antibiotic dosage or cocktail of broad-spectrum antibiotics, aggravating the severity of antibiotic resistance. Notably, the lack of intrinsic antibacterial properties in commercial-grade materials desires to develop newer functionalized materials to prevent biofilm formation on their surfaces. To devise newer strategies, materials prepared at the nanoscale demonstrated reasonable antibacterial properties or enhanced the activity of antimicrobial agents (that are encapsulated/chemically functionalized onto the material surface). In this manuscript, we compiled such nanosized materials, specifying their role in targeting specific strains of bacteria. We also enlisted the examples of nanomaterials, nanodevice, nanomachines, nano-camouflaging, and nano-antibiotics for bactericidal activity and their possible clinical implications.Copyright © 2023 The Author(s)

Evaluation of anti-biofilm formation and quorum sensing attenuation of herbal medicines

Excessive, and in most cases, unnecessary intake of antibacterial drugs sparked the emergence of microorganisms with multidrug resistance. The recent pandemic of COVID-19 has unmistakably revealed the catastrophic effects of infectious diseases facing humanity. Besides, the World Health Organization (WHO) has already published a priority list of names of bacteria requiring immediate attention for developing new antibiotics. Hence, novel therapies for the treatment of contagious diseases are urgently needed, leading to a tremendous focus by scientists on the development of such therapies. Microorganisms are known to dwell in a complex organization called biofilm, which can be described as a matrix consisting of polymeric substances that allows attachment to various surfaces. Bacteria exploit biofilms as an effective way of communication via the release of chemical signaling compounds without direct physical contact. Quorum sensing is the name of the mechanism prompting the communication among microorganisms via the release of signal molecules. This mechanism arranges the bacterial response for their adaptation to the changing conditions of the environment through the liberation of extracellular molecules. These molecules are received by other bacteria, culminating in a series of regulated modifications in their physiology and providing a great advantage for their adaptation process. The inhibition of the quorum sensing mechanism draws a broad interest of the scientific community worldwide as a novel defense strategy tackling communicable diseases, particularly caused by microorganisms with resistance to antibiotic drugs. Furthermore, this approach does not induce a direct action on the microorganism, and it is expected to generate less bacterial resistance to itself. In other terms, instead of killing the microorganisms, their virulence is weakened. Plants have been utilized against infectious diseases for a long time. As the demand for alternative strategies against such diseases surges, the scientific interest in plants for the determination of their possible activities against microorganisms rises simultaneously. Numerous studies have shown that herbal medicinal products provide a huge resource of bioactive compounds with the inhibitory activity of quorum sensing and biofilm formation of various microorganisms. Among them, plants rich in various phenolic compounds, essential oils and other terpenic compounds constitute a major place for fighting against both Gram-positive and Gram-negative bacteria. Several in-depth reports stated the efficacy of plants containing such compounds in inhibiting the quorum sensing and biofilm formation of such organisms. Given the urgency for the discovery of new and efficient ways of coping with infectious diseases, traditional medicine and the use of plant sources constitute a significant and viable source for readiness to "post-antibiotics era.” Graphical abstract Unlabelled Image © 2022 Elsevier Inc. All rights reserved.

Effects of physicochemical changes (temperature, pH, and culture media) on strong biofilm formation of Acinetobacter baumannii isolated from patients with respiratory infection in Iraq

Introduction and Aim: The ability of Acinetobacter baumannii to form biofilms on biotic and abiotic surfaces is regulated by several pathogens' virulence factors, and this is thought to be at the root of the bacteria's resistance to antibiotics. We hope to learn how temperature, pH, and iron concentrations influence the development of biofilms in A. baumannii isolated from COVID-19 and non-COVID-19 individuals, and which genes are relevant for biofilm formation and antibiotic resistance. Material(s) and Method(s): Eight strong adherent isolates of A. baumannii from respiratory tract infection Iraqi patients (4 from COVID-19 and the other from non-COVID-19 just respiratory patients) had been used in this study which conducted from 10/1/2021 to 10/2/2022. The antibiotic sensitivity of all isolates was determined using the VITEK-2 system. The biofilm associated genes OXA-51, bap, Chaperone Usher (CsuE) and Integron-1, was detected using PCR. Isolates of A. baumainni were put through a battery of tests to determine whether they possessed the capacity to produce robust biofilms under a wide range of both physical (temperature, pH) and chemical circumstances. Result(s): A. baumannii showed that all isolates were multidrug resistant and positive for the biofilm genes studied. Effect on temperature on biofilm formation showed at 44C biofilm formation was significantly lower than that at 37C (mean differences of 0.178000 (t= 8.355, df:3, P=0.004) and 0.204000 (t=26.521, df:3, P=0.000) respectively). The adhesion factor value in the COVID-19 positive and negative groups decreased significantly because of the pH change. Iron concentration of 60 microM significantly lowered biofilm formation among COVID-19 group and non-COVID-19 group. Conclusion(s): A. baumanni are multidrug resistance isolates with a capacity to form biofilms. The ability to form biofilms by A. baumannii is strongly influenced by physical and chemical factors.Copyright © 2023, Indian Association of Biomedical Scientists. All rights reserved.

Dental Care during the COVID-19 Pandemic

Background: The rampant spread of SARS-CoV-2 worldwide increases the likelihood that dental health care professionals will treat this subset of the patient population. Due to the characteristics of the profession and the virus, two situations deserve attention: the disinfection of surfaces that can be contaminated during dental treatment and the presence of the virus in the oral cavity and the countless possibilities of microbial interaction with microorganisms in the oral cavity. Objective(s): The objective of this review was to point out the current stage of the discussion on dental bio-safety involving professionals, the work team and patients. Method(s): The following databases were consulted: MEDLINE (National Library of Medicine, USA-NLM), Lilacs, Scielo, Embase, Web of Science and Google Academic with the keywords COVID-19 and dental practice, dentistry, oral conditions, mouthrinses. Result(s): Disinfection of surfaces has always been paramount and the protocol to prevent the spread of SARS-CoV-2 seems to be established. SARS-CoV-2 is vulnerable to oxidation, it is recommended to use a mouth rinse containing oxidizing agents. Conclusion(s): Dentists are among the professionals who are most at risk of COVID-19 infection, and they must have extra attention during this period, biosafety measures must be reinforced and patients must be motivated to maintain a strict oral hygiene routine so that there is no accumulation of biofilm and this may somehow interfere with their systemic condition.Copyright © 2021 Bentham Science Publishers.

Betaine- and L-Carnitine-Based Ionic Liquids as Solubilising and Stabilising Agents for the Formulation of Antimicrobial Eye Drops Containing Diacerein.

The therapeutic efficacy of topically administered drugs, however powerful, is largely affected by their bioavailability and, thus, ultimately, on their aqueous solubility and stability. The aim of this study was to evaluate the use of ionic liquids (ILs) as functional excipients to solubilise, stabilise, and prolong the ocular residence time of diacerein (DIA) in eye drop formulations. DIA is a poorly soluble and unstable anthraquinone prodrug, rapidly hydrolysed to rhein (Rhe), for the treatment of osteoarthritis. DIA has recently been evaluated as an antimicrobial agent for bacterial keratitis. Two ILs based on natural zwitterionic compounds were investigated: L-carnitine C6 alkyl ester bromide (Carn6), and betaine C6 alkyl ester bromide (Bet6). The stabilising, solubilising, and mucoadhesive properties of ILs were investigated, as well as their cytotoxicity to the murine fibroblast BALB/3T3 clone A31 cell line. Two IL-DIA-based eye drop formulations were prepared, and their efficacy against both Staphylococcus aureus and Pseudomonas aeruginosa was determined. Finally, the eye drops were administered in vivo on New Zealand albino rabbits, testing their tolerability as well as their elimination and degradation kinetics. Both Bet6 and Carn6 have good potential as functional excipients, showing solubilising, stabilising, mucoadhesive, and antimicrobial properties; their in vitro cytotoxicity and in vivo ocular tolerability pave the way for their future use in ophthalmic applications.

Recent Developments in the Inhibition of Bacterial Adhesion as Promising Anti-Virulence Strategy.

Infectious diseases caused by antimicrobial-resistant strains have become a serious threat to global health, with a high social and economic impact. Multi-resistant bacteria exhibit various mechanisms at both the cellular and microbial community levels. Among the different strategies proposed to fight antibiotic resistance, we reckon that the inhibition of bacterial adhesion to host surfaces represents one of the most valid approaches, since it hampers bacterial virulence without affecting cell viability. Many different structures and biomolecules involved in the adhesion of Gram-positive and Gram-negative pathogens can be considered valuable targets for the development of promising tools to enrich our arsenal against pathogens.

Antibacterial, Anti-Biofilm and Pro-Migratory Effects of Double Layered Hydrogels Packaged with Lactoferrin-DsiRNA-Silver Nanoparticles for Chronic Wound Therapy.

Antimicrobial resistance and biofilm formation in diabetic foot infections worsened during the COVID-19 pandemic, resulting in more severe infections and increased amputations. Therefore, this study aimed to develop a dressing that could effectively aid in the wound healing process and prevent bacterial infections by exerting both antibacterial and anti-biofilm effects. Silver nanoparticles (AgNPs) and lactoferrin (LTF) have been investigated as alternative antimicrobial and anti-biofilm agents, respectively, while dicer-substrate short interfering RNA (DsiRNA) has also been studied for its wound healing effect in diabetic wounds. In this study, AgNPs were complexed with LTF and DsiRNA via simple complexation before packaging in gelatin hydrogels. The formed hydrogels exhibited 1668% maximum swellability, with a 46.67 ± 10.33 µm average pore size. The hydrogels demonstrated positive antibacterial and anti-biofilm effects toward the selected Gram-positive and Gram-negative bacteria. The hydrogel containing AgLTF at 125 µg/mL was also non-cytotoxic on HaCaT cells for up to 72 h of incubation. The hydrogels containing DsiRNA and LTF demonstrated superior pro-migratory effects compared to the control group. In conclusion, the AgLTF-DsiRNA-loaded hydrogel possessed antibacterial, anti-biofilm, and pro-migratory activities. These findings provide a further understanding and knowledge on forming multipronged AgNPs consisting of DsiRNA and LTF for chronic wound therapy.