Combating planktonic and biofilm growth of Serratia marcescens by repurposing ebselen / Combatir el crecimiento planctónico y de biopelículas de Serratia marcescens mediante la reutilización de ebselen

Aim of the study: The rising instances of multidrug-resistant pathogens are rapidly evolving into a global healthcare crisis. Identifying new ways of synthesis of antibiotics is both time-consuming and expensive. Repurposing existing drugs for the treatment of such antimicrobial-resistant pathogens has also been explored. Methods and results: In the current study, ebselen was screened for antibacterial and antibiofilm activity against Serratia marcescens. Various antibacterial studies such as minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill curves, intracellular reactive oxygen species (ROS) quantification, and colony-forming unit assays were performed. The antibiofilm potential was assayed by biofilm inhibition, cell surface hydrophobicity assay, eradication, quantification of extracellular DNA (eDNA), and extracellular polymeric substance (EPS) layer and scanning electron microscopy (SEM) analysis were performed. Anti-quorum sensing assay was validated by quantifying the virulence factors production. Further molecular docking of ebselen with two quorum sensing (QS) specific proteins was also carried out. Antibacterial susceptibility tests showed potent antimicrobial activity of ebselen against S. marcescens with MIC50 of 14 μg/mL. Ebselen’s ability to disturb the redox environment by inducing significant ROS generation led to bacterial death. It also showed concentration-dependent bactericidal activity as indicated by reduced bacterial growth and colony-forming unit propagation. Ebselen was also found to prevent biofilm attachment by altering the cell surface hydrophobicity while also being effective against preformed biofilms as validated by scanning electron microscopy (SEM) analysis. Additionally, ebselen showed reduced virulence factors like urease enzyme activity and prodigiosin pigment production indicating its promising anti-quorum sensing potential...(AU)

Combating planktonic and biofilm growth of Serratia marcescens by repurposing ebselen.

AIM OF THE STUDY: The rising instances of multidrug-resistant pathogens are rapidly evolving into a global healthcare crisis. Identifying new ways of synthesis of antibiotics is both time-consuming and expensive. Repurposing existing drugs for the treatment of such antimicrobial-resistant pathogens has also been explored. METHODS AND RESULTS: In the current study, ebselen was screened for antibacterial and antibiofilm activity against Serratia marcescens. Various antibacterial studies such as minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time-kill curves, intracellular reactive oxygen species (ROS) quantification, and colony-forming unit assays were performed. The antibiofilm potential was assayed by biofilm inhibition, cell surface hydrophobicity assay, eradication, quantification of extracellular DNA (eDNA), and extracellular polymeric substance (EPS) layer and scanning electron microscopy (SEM) analysis were performed. Anti-quorum sensing assay was validated by quantifying the virulence factors production. Further molecular docking of ebselen with two quorum sensing (QS) specific proteins was also carried out. Antibacterial susceptibility tests showed potent antimicrobial activity of ebselen against S. marcescens with MIC50 of 14 µg/mL. Ebselen's ability to disturb the redox environment by inducing significant ROS generation led to bacterial death. It also showed concentration-dependent bactericidal activity as indicated by reduced bacterial growth and colony-forming unit propagation. Ebselen was also found to prevent biofilm attachment by altering the cell surface hydrophobicity while also being effective against preformed biofilms as validated by scanning electron microscopy (SEM) analysis. Additionally, ebselen showed reduced virulence factors like urease enzyme activity and prodigiosin pigment production indicating its promising anti-quorum sensing potential. Molecular docking analysis validated the strong binding of ebselen with QS-specific proteins (1Joe and PigG) with binding energies of - 6.6 and - 8.1kj/mol through hydrogen bonds and aromatic interactions. These results show that ebselen has potent antibiofilm potential that can be explored to identify treatment against bacterial infections.

Elucidating the anti-biofilm and anti-quorum sensing potential of selenocystine against respiratory tract infections causing bacteria: in vitro and in silico studies.

Bacteria are increasingly relying on biofilms to develop resistance to antibiotics thereby resulting in their failure in treating many infections. In spite of continuous research on many synthetic and natural compounds, ideal anti-biofilm molecule is still not found thereby warranting search for new class of molecules. The current study focuses on exploring anti-biofilm potential of selenocystine against respiratory tract infection (RTI)-causing bacteria. Anti-bacterial and anti-biofilm assays demonstrated that selenocystine inhibits the growth of bacteria in their planktonic state, and formation of biofilms while eradicating preformed-biofilm effectively. Selenocystine at a MIC50 as low as 42 and 28 µg/mL effectively inhibited the growth of Klebsiella pneumonia and Pseudomonas aeruginosa. The antibacterial effect is further reconfirmed by agar cup diffusion assay and growth-kill assay. Selenocystine showed 30-60% inhibition of biofilm formation in K. pneumonia, and 44-70% in P. aeruginosa respectively. It also distorted the preformed-biofilms by degrading the eDNA component of the Extracellular Polymeric Substance matrix. Molecular docking studies of selenocystine with quorum sensing specific proteins clearly showed that through the carboxylic acid moiety it interacts and inhibits the protein function, thereby confirming its anti-biofilm potential. With further validation selenocystine can be explored as a potential candidate for the treatment of RTIs.

Use of the ReCIVA device in breath sampling of patients with acute breathlessness: a feasibility study.

INTRODUCTION: Investigating acute multifactorial undifferentiated breathlessness and understanding the driving inflammatory processes can be technically challenging in both adults and children. Being able to validate noninvasive methods such as breath analysis would be a huge clinical advance. The ReCIVA® device allows breath samples to be collected directly onto sorbent tubes at the bedside for analysis of exhaled volatile organic compounds (eVOCs). We aimed to assess the feasibility of using this device in acutely breathless patients. METHODS: Adults hospitalised with acute breathlessness and children aged 5-16 years with acute asthma or chronic stable asthma, as well as healthy adult and child volunteers, were recruited. Breath samples were collected onto sorbent tubes using the ReCIVA® device and sent for analysis by means of two-dimensional gas chromatography-mass spectrometry (GCxGC-MS). The NASA Task Load Index (NASA-TLX) was used to assess the perceived task workload of undertaking sampling from the patient's perspective. RESULTS: Data were available for 65 adults and 61 children recruited. In total, 98.4% of adults and 75.4% of children were able to provide the full target breath sample using the ReCIVA® device. NASA-TLX measurements were available in the adult population with mean values of 3.37 for effort, 2.34 for frustration, 3.8 for mental demand, 2.8 for performance, 3.9 for physical demand and 2.8 for temporal demand. DISCUSSION: This feasibility study demonstrates it is possible and acceptable to collect breath samples from both adults and children at the bedside for breathomics analysis using the ReCIVA® device.

Assessment of breath volatile organic compounds in acute cardiorespiratory breathlessness: a protocol describing a prospective real-world observational study.

INTRODUCTION: Patients presenting with acute undifferentiated breathlessness are commonly encountered in admissions units across the UK. Existing blood biomarkers have clinical utility in distinguishing patients with single organ pathologies but have poor discriminatory power in multifactorial presentations. Evaluation of volatile organic compounds (VOCs) in exhaled breath offers the potential to develop biomarkers of disease states that underpin acute cardiorespiratory breathlessness, owing to their proximity to the cardiorespiratory system. To date, there has been no systematic evaluation of VOC in acute cardiorespiratory breathlessness. The proposed study will seek to use both offline and online VOC technologies to evaluate the predictive value of VOC in identifying common conditions that present with acute cardiorespiratory breathlessness. METHODS AND ANALYSIS: A prospective real-world observational study carried out across three acute admissions units within Leicestershire. Participants with self-reported acute breathlessness, with a confirmed primary diagnosis of either acute heart failure, community-acquired pneumonia and acute exacerbation of asthma or chronic obstructive pulmonary disease will be recruited within 24 hours of admission. Additionally, school-age children admitted with severe asthma will be evaluated. All participants will undergo breath sampling on admission and on recovery following discharge. A range of online technologies including: proton transfer reaction mass spectrometry, gas chromatography ion mobility spectrometry, atmospheric pressure chemical ionisation-mass spectrometry and offline technologies including gas chromatography mass spectroscopy and comprehensive two-dimensional gas chromatography-mass spectrometry will be used for VOC discovery and replication. For offline technologies, a standardised CE-marked breath sampling device (ReCIVA) will be used. All recruited participants will be characterised using existing blood biomarkers including C reactive protein, brain-derived natriuretic peptide, troponin-I and blood eosinophil levels and further evaluated using a range of standardised questionnaires, lung function testing, sputum cell counts and other diagnostic tests pertinent to acute disease. ETHICS AND DISSEMINATION: The National Research Ethics Service Committee East Midlands has approved the study protocol (REC number: 16/LO/1747). Integrated Research Approval System (IRAS) 198921. Findings will be presented at academic conferences and published in peer-reviewed scientific journals. Dissemination will be facilitated via a partnership with the East Midlands Academic Health Sciences Network and via interaction with all UK-funded Medical Research Council and Engineering and Physical Sciences Research Council molecular pathology nodes. TRIAL REGISTRATION NUMBER: NCT03672994.

Fiessinger-Leroy's disease: A rare case report.

Fiessinger-Leroy's disease (Reiter's disease) is rare and not commonly reported in India. This paper reports a case of a 35-year-old male with Fiessinger-Leroy's disease, occurring after balanitis. The patient presented with symmetrical polyarthritis, pruritic scaly plaques, keratoderma blenorrhagicum, and hematuria with histopathology of skin suggestive of Fiessinger-Leroy's disease. The case is presented with a view to document the occurrence of the same in India.

Crusted Scabies: Presenting as erythroderma in a human immunodeficiency virus-seropositive patient.

Crusted scabies is a rare manifestation of scabies characterized by uncontrolled proliferation of mites in the skin. It is common in patients with sensory neuropathy, mentally retarded persons and in patients who are immunosuppressed. Further, crusted scabies can rarely present as erythroderma (<0.5% cases) necessitating a high index of suspicion for its diagnosis. Because of its rare occurrence, we are reporting a case of crusted scabies presenting as erythroderma, in a human immunodeficiency virus seropositive patient.

The G protein α chaperone Ric-8 as a potential therapeutic target.

Resistance to inhibitors of cholinesterase (Ric-8)A and Ric-8B are essential genes that encode positive regulators of heterotrimeric G protein α subunits. Controversy persists surrounding the precise way(s) that Ric-8 proteins affect G protein biology and signaling. Ric-8 proteins chaperone nucleotide-free Gα-subunit states during biosynthetic protein folding prior to G protein heterotrimer assembly. In organisms spanning the evolutionary window of Ric-8 expression, experimental perturbation of Ric-8 genes results in reduced functional abundances of G proteins because G protein α subunits are misfolded and degraded rapidly. Ric-8 proteins also act as Gα-subunit guanine nucleotide exchange factors (GEFs) in vitro. However, Ric-8 GEF activity could strictly be an in vitro phenomenon stemming from the ability of Ric-8 to induce partial Gα unfolding, thereby enhancing GDP release. Ric-8 GEF activity clearly differs from the GEF activity of G protein-coupled receptors (GPCRs). G protein ßγ is inhibitory to Ric-8 action but obligate for receptors. It remains an open question whether Ric-8 has dual functions in cells and regulates G proteins as both a molecular chaperone and GEF. Clearly, Ric-8 has a profound influence on heterotrimeric G protein function. For this reason, we propose that Ric-8 proteins are as yet untested therapeutic targets in which pharmacological inhibition of the Ric-8/Gα protein-protein interface could serve to attenuate the effects of disease-causing G proteins (constitutively active mutants) and/or GPCR signaling. This minireview will chronicle the understanding of Ric-8 function, provide a comparative discussion of the Ric-8 molecular chaperoning and GEF activities, and support the case for why Ric-8 proteins should be considered potential targets for development of new therapies.

White piedra of scalp hair by Trichosporon inkin.

White piedra is a rare fungal infection of hair and is reported to be all the more rare on scalp. Trichosporon inkin is usually associated with white piedra of pubic hair. We report a case of white piedra of scalp hair caused by T. inkin. This is the first case reported from India and the fifth case reported worldwide. A 50-year-old Muslim female presented with white knots over scalp hair. Diagnosis of Trichosporon was made by examining KOH mounts of epilated hair and Lactophenol Cotton Blue preparations of the growth in culture. Automated mini-API test (for biochemical profiles) and Electronmicroscopy studies (for cell wall structures) helped in identification of the species. Mini-API test was also positive for Cryptococcus curvatus which could be due to similarity in biochemical and physiological properties of the two species. Absence of C. curvatus on culture further supports this view. Topical antifungal therapy resulted in clinical clearance within 2 months. Higher incidence of scalp white piedra is observed in Muslim females; contributing factor being the custom of using a veil, leading to higher humidity and limited sunlight exposure.