ANTIFUNGAL ACTIVITY OF BIPHENYL-2,6-DIETHANONE DERIVATIVES

Objective: The objective of the study was to evaluate the antifungal activity of biphenyl-2,6-diethanone derivatives against Cryptococcus neoformans.Methods: Antifungal activity of biphenyl derivatives were evaluated against C. neoformans. Zone of inhibition by disc diffusion method and minimum inhibitory concentration (MIC) using micro-broth dilution method was performed as per clinical and laboratory standard institute (CLSI). Melanin was extracted using 1M KOH, purified using 6M HCL and its reduction was assayed spectrophotometrically at 530 nm. Laccase activity was measured using L-DOPA as substrate and was assayed spectrophotometrically at 480 nm. Time kill assay was also performed to compare the antifungal potency of the test compound against azole drug.Results: Zone of inhibition of 12 mm diameter was estimated against C. neoformans. MIC80 of compound 1e was calculated as 50µg/ml. 63.67% decrease in melanization and 57.44% laccase activity reduction was determined. The Time-kill assay illustrated that the compound 1e inhibited the growth of C. neoformans cells in almost the same duration as observed in fluconazole.Conclusion: The outcome of in vitro antifungal studies indicated that compound 1e demonstrated maximum reduction of melanin and laccase activity in C. neoformans. In conclusion, biphenyl-2,6-diethanone derivatives possess significant antifungal property which can be explored further for lead generation.Â

MORINDA COREIA HAS AN ANTI-HELICOBACTER PYLORI EFFECT AGAINST THE MULTIDRUG-RESISTANT CLINICAL ISOLATE OF NORTH-EAST INDIA

Objective: Antimicrobial resistance is a growing problem in Helicobacter pylori eradication which is a microaerophilic bacterium causing various gastroduodenal diseases. The present study has been designed to test the efficacy of Morinda coreia against the metronidazole clarithromycin and levofloxacin-resistant H. pylori strains isolated from the biopsy taken from the patient suffering from gastric erosion in Guwahati, Assam.Method: The antimicrobial activity of n-hexane and chloroform extract of M. coreia was tested against multidrug-resistant H. pylori isolate of Guwahati, Assam, by agar well method and microdilution method.Result: In the present study, the H. pylori strain resistant for metronidazole (minimal inhibitory concentration [MIC] >64 μg/mL), clarithromycin at (MIC >0.5 μg/mL), and levofloxacin at (MIC >1 μg/mL) was tested against the n-hexane and chloroform extract of M. coreia. Both the extracts of M. coreia showed good efficacy against the multidrug-resistant strain of H. pylori shown inhibition at 1.2 μg/mL with n-hexane extract and 2 μg/mL with chloroform extract of M. coreia. Conclusion: The prevalence of metronidazole-resistant ranges between 50% and 90% in the developing countries, including India, clarithromycin ranges from 0% to 15% in India, and levofloxacin ranges between 50% and 70% in India, so there is a need of alternative therapy for the eradication of this bacterium from the stomach. Hence, this study suggests that M. coreia, which has been used traditionally as a folk medicine for the treatment of many gastric diseases, has also shown good efficacy against the multidrug-resistant H. pylori strain of North-east India

cyp51A mutations, protein modeling, and efflux pump gene expression reveals multifactorial complexity towards understanding Aspergillus section Nigri azole resistance mechanism

Abstract Black Aspergillus species are the most common etiological agents of otomycosis, and pulmonary aspergillosis. However, limited data is available on their antifungal susceptibility profiles and associated resistance mechanisms. Here, we determined the azole susceptibility profiles of black Aspergillus species isolated from the Indian environment and explored the potential resistance mechanisms through cyp51A gene sequencing, protein homology modeling, and expression analysis of selected genes cyp51A, cyp51B, mdr1, and mfs based on their role in imparting resistance against antifungal drugs. In this study, we have isolated a total of 161 black aspergilli isolates from 174 agricultural soil samples. Isolates had variable resistance towards medical azoles; approximately 11.80%, 3.10%, and 1.24% of isolates were resistant to itraconazole (ITC), posaconazole (POS), and voriconazole (VRC), respectively. Further, cyp51A sequence analysis showed that non-synonymous mutations were present in 20 azole-resistant Aspergillus section Nigri and 10 susceptible isolates. However, Cyp51A homology modeling indicated insignificant protein structural variations because of these mutations. Most of the isolates showed the overexpression of mdr1, and mfs genes. Hence, the study concluded that azole-resistance in section Nigri cannot be attributed exclusively to the cyp51A gene mutation or its overexpression. However, overexpression of mdr1 and mfs genes may have a potential role in drug resistance

Molecular virulence determinants of Magnaporthe oryzae: disease pathogenesis and recent interventions for disease management in rice plant

Magnaporthe oryzae, causative agent of the rice blast disease, is a major concern for the loss in yield of rice crop across the globe. It is known for its characteristic melanised dome-shaped appressorium containing a dense melanin layer. The melanised layer is of considerable importance as it is required to generate turgor pressure for initiating peg formation, consequently rupturing the plant cuticle. Various virulence factors play an important role in the disease progression as well as pathogenesis of the fungus. Some of the proteins encoded by virulence genes are associated with signalling, secondary metabolism, protein deprivation, defence responses and conidiation. The purpose of this review is to describe various fungal virulence determinants and provide insights into the molecular mechanisms that are involved in progression of the disease. Besides, the recent molecular approaches being employed to combat the rice blast have also been elaborated

Antifungal Resistance Analysis of Environmental Isolates of Aspergillus in North India

Triazoles are the major group of antifungals for treating Aspergillus infections. The morbidity and mortality associated with these infections is high and rate of treatment failure is more in patients infected with azole resistant Aspergillus. The azole resistant Aspergillus isolates have been recovered from both azole treated and azole naive patients. Thus, there may be an environmental route of exposure to azole resistant Aspergillus. The present study was envisaged for the isolation and enumeration of environmental isolates of Aspergillus resistant to medically available antifungal azole drugs in North Indian environment. A total of 25 soil samples were collected from North Indian agricultural farms where azole pesticides were being used. The soil samples were screened for Aspergillus isolates by serial dilution pour plate method. Further, their drug susceptibility testing was performed using disc diffusion, E- strip and micro-broth dilution method against medically available triazoles: itraconazole, ketoconazole, fluconazole and voriconazole. A total of 41 Aspergillus species were isolated from the soil samples. Based on conventional microscopic assay, 13 of them were identified as Aspergillus fumigatus, 9 as Aspergillus niger, 5 as Aspergillus terreus, 3 as Aspergillus nidulans, 1 as Aspergillus flavus and 9 as other Aspergillus species. Resistance for all tested antifungal drugs was detected in 7.3% Aspergillus isolates and 43.7% isolates were resistant to any of the tested azole drugs. The results demonstrated that Aspergillus isolates resistant to medical triazoles are present in the agricultural farms

DataSheet_1_4-Allyl-2-methoxyphenol modulates the expression of genes involved in efflux pump, biofilm formation and sterol biosynthesis in azole resistant Aspergillus fumigatus.docx

IntroductionAntifungal therapy for aspergillosis is becoming problematic because of the toxicity of currently available drugs, biofilm formation on host surface, and increasing prevalence of azole resistance in Aspergillus fumigatus. Plants are rich source of bioactive molecules and antimicrobial activity of aromatic bioactive compounds draws attention because of its promising biological properties. The present study elucidated the antibiofilm activity of 4-allyl-2-methoxyphenol (eugenol) against azole-resistant environmental A. fumigatus isolates.MethodsSoil samples were collected from agricultural fields across India; azole-resistant A. fumigatus (ARAF) were isolated followed by their molecular identification. Antibiofilm activity of eugenol was calculated via tetrazolium based-MTT assay. The expression of the multidrug efflux pumps genes MDR1, MDR4, transporters of the MFS gene, erg11A gene encoding 14α demethylase, and transcription regulatory genes, MedA, SomA and SrbA, involved in biofilm formation of A. fumigatus were calculated by quantitative real time PCR.ResultsOut of 89 A. fumigatus isolates, 10 were identified as azole resistant. Eugenol exhibited antibiofilm activity against ARAF isolates, ranging from 312 to 500 µg/mL. Confocal laser scanning microscopy analysis revealed absence of extracellular matrix of ARAF biofilm after eugenol treatment. The gene expression indicated significantly low expression of efflux pumps genes MDR1, MDR4, erg11A and MedA in eugenol treated ARAF isolates when compared with untreated isolates.ConclusionsOur results demonstrate that eugenol effects the expression of efflux pump and biofilm associated genes as well as inhibits biofilm formation in azole resistant isolates of A. fumigatus.</p

Molecular Insights Into Development and Virulence Determinants of Aspergilli: A Proteomic Perspective

Aspergillus species are the major cause of health concern worldwide in immunocompromised individuals. Opportunistic Aspergilli cause invasive to allergic aspergillosis, whereas non-infectious Aspergilli have contributed to understand the biology of eukaryotic organisms and serve as a model organism. Morphotypes of Aspergilli such as conidia or mycelia/hyphae helped them to survive in favorable or unfavorable environmental conditions. These morphotypes contribute to virulence, pathogenicity and invasion into hosts by excreting proteins, enzymes or toxins. Morphological transition of Aspergillus species has been a critical step to infect host or to colonize on food products. Thus, we reviewed proteins from Aspergilli to understand the biological processes, biochemical, and cellular pathways that are involved in transition and morphogenesis. We majorly analyzed proteomic studies on A. fumigatus, A. flavus, A. terreus, and A. niger to gain insight into mechanisms involved in the transition from conidia to mycelia along with the role of secondary metabolites. Proteome analysis of morphotypes of Aspergilli provided information on key biological pathways required to exit conidial dormancy, consortia of virulent factors and mycotoxins during the transition. The application of proteomic approaches has uncovered the biological processes during development as well as intermediates of secondary metabolite biosynthesis pathway. We listed key proteins/ enzymes or toxins at different morphological types of Aspergillus that could be applicable in discovery of novel therapeutic targets or metabolite based diagnostic markers

An international observational study to assess the impact of the Omicron variant emergence on the clinical epidemiology of COVID-19 in hospitalised patients

Background: Whilst timely clinical characterisation of infections caused by novel SARS-CoV-2 variants is necessary for evidence-based policy response, individual-level data on infecting variants are typically only available for a minority of patients and settings. Methods: Here, we propose an innovative approach to study changes in COVID-19 hospital presentation and outcomes after the Omicron variant emergence using publicly available population-level data on variant relative frequency to infer SARS-CoV-2 variants likely responsible for clinical cases. We apply this method to data collected by a large international clinical consortium before and after the emergence of the Omicron variant in different countries. Results: Our analysis, that includes more than 100,000 patients from 28 countries, suggests that in many settings patients hospitalised with Omicron variant infection less often presented with commonly reported symptoms compared to patients infected with pre-Omicron variants. Patients with COVID-19 admitted to hospital after Omicron variant emergence had lower mortality compared to patients admitted during the period when Omicron variant was responsible for only a minority of infections (odds ratio in a mixed-effects logistic regression adjusted for likely confounders, 0.67 [95% confidence interval 0.61-0.75]). Qualitatively similar findings were observed in sensitivity analyses with different assumptions on population-level Omicron variant relative frequencies, and in analyses using available individual-level data on infecting variant for a subset of the study population. Conclusions: Although clinical studies with matching viral genomic information should remain a priority, our approach combining publicly available data on variant frequency and a multi-country clinical characterisation dataset with more than 100,000 records allowed analysis of data from a wide range of settings and novel insights on real-world heterogeneity of COVID-19 presentation and clinical outcome

Respiratory support in patients with severe COVID-19 in the International Severe Acute Respiratory and Emerging Infection (ISARIC) COVID-19 study: a prospective, multinational, observational study

Background: Up to 30% of hospitalised patients with COVID-19 require advanced respiratory support, including high-flow nasal cannulas (HFNC), non-invasive mechanical ventilation (NIV), or invasive mechanical ventilation (IMV). We aimed to describe the clinical characteristics, outcomes and risk factors for failing non-invasive respiratory support in patients treated with severe COVID-19 during the first two years of the pandemic in high-income countries (HICs) and low middle-income countries (LMICs). Methods: This is a multinational, multicentre, prospective cohort study embedded in the ISARIC-WHO COVID-19 Clinical Characterisation Protocol. Patients with laboratory-confirmed SARS-CoV-2 infection who required hospital admission were recruited prospectively. Patients treated with HFNC, NIV, or IMV within the first 24 h of hospital admission were included in this study. Descriptive statistics, random forest, and logistic regression analyses were used to describe clinical characteristics and compare clinical outcomes among patients treated with the different types of advanced respiratory support. Results: A total of 66,565 patients were included in this study. Overall, 82.6% of patients were treated in HIC, and 40.6% were admitted to the hospital during the first pandemic wave. During the first 24 h after hospital admission, patients in HICs were more frequently treated with HFNC (48.0%), followed by NIV (38.6%) and IMV (13.4%). In contrast, patients admitted in lower- and middle-income countries (LMICs) were less frequently treated with HFNC (16.1%) and the majority received IMV (59.1%). The failure rate of non-invasive respiratory support (i.e. HFNC or NIV) was 15.5%, of which 71.2% were from HIC and 28.8% from LMIC. The variables most strongly associated with non-invasive ventilation failure, defined as progression to IMV, were high leukocyte counts at hospital admission (OR [95%CI]; 5.86 [4.83-7.10]), treatment in an LMIC (OR [95%CI]; 2.04 [1.97-2.11]), and tachypnoea at hospital admission (OR [95%CI]; 1.16 [1.14-1.18]). Patients who failed HFNC/NIV had a higher 28-day fatality ratio (OR [95%CI]; 1.27 [1.25-1.30]). Conclusions: In the present international cohort, the most frequently used advanced respiratory support was the HFNC. However, IMV was used more often in LMIC. Higher leucocyte count, tachypnoea, and treatment in LMIC were risk factors for HFNC/NIV failure. HFNC/NIV failure was related to worse clinical outcomes, such as 28-day mortality. Trial registration This is a prospective observational study; therefore, no health care interventions were applied to participants, and trial registration is not applicable

Respiratory support in patients with severe COVID-19 in the International Severe Acute Respiratory and Emerging Infection (ISARIC) COVID-19 study: a prospective, multinational, observational study

Background: Up to 30% of hospitalised patients with COVID-19 require advanced respiratory support, including high-flow nasal cannulas (HFNC), non-invasive mechanical ventilation (NIV), or invasive mechanical ventilation (IMV). We aimed to describe the clinical characteristics, outcomes and risk factors for failing non-invasive respiratory support in patients treated with severe COVID-19 during the first two years of the pandemic in high-income countries (HICs) and low middle-income countries (LMICs). Methods: This is a multinational, multicentre, prospective cohort study embedded in the ISARIC-WHO COVID-19 Clinical Characterisation Protocol. Patients with laboratory-confirmed SARS-CoV-2 infection who required hospital admission were recruited prospectively. Patients treated with HFNC, NIV, or IMV within the first 24 h of hospital admission were included in this study. Descriptive statistics, random forest, and logistic regression analyses were used to describe clinical characteristics and compare clinical outcomes among patients treated with the different types of advanced respiratory support. Results: A total of 66,565 patients were included in this study. Overall, 82.6% of patients were treated in HIC, and 40.6% were admitted to the hospital during the first pandemic wave. During the first 24 h after hospital admission, patients in HICs were more frequently treated with HFNC (48.0%), followed by NIV (38.6%) and IMV (13.4%). In contrast, patients admitted in lower- and middle-income countries (LMICs) were less frequently treated with HFNC (16.1%) and the majority received IMV (59.1%). The failure rate of non-invasive respiratory support (i.e. HFNC or NIV) was 15.5%, of which 71.2% were from HIC and 28.8% from LMIC. The variables most strongly associated with non-invasive ventilation failure, defined as progression to IMV, were high leukocyte counts at hospital admission (OR [95%CI]; 5.86 [4.83–7.10]), treatment in an LMIC (OR [95%CI]; 2.04 [1.97–2.11]), and tachypnoea at hospital admission (OR [95%CI]; 1.16 [1.14–1.18]). Patients who failed HFNC/NIV had a higher 28-day fatality ratio (OR [95%CI]; 1.27 [1.25–1.30]). Conclusions: In the present international cohort, the most frequently used advanced respiratory support was the HFNC. However, IMV was used more often in LMIC. Higher leucocyte count, tachypnoea, and treatment in LMIC were risk factors for HFNC/NIV failure. HFNC/NIV failure was related to worse clinical outcomes, such as 28-day mortality. Trial registration This is a prospective observational study; therefore, no health care interventions were applied to participants, and trial registration is not applicable