Publications by authors named "Alok Chakrabarti"

The growing prevalence of antimicrobial resistance (AMR) necessitates the development of new treatment methods to combat diseases like cholera. Lytic bacteriophages are viruses that specifically target and lyse bacteria upon infection, making them a possible treatment option for multi-drug-resistant pathogens. The current study investigated the potential role of bacteriophages isolated from clinical stool and sewage water samples in treating multi-drug-resistant infection, finding that over 95% of the strains were susceptible.

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Background: Limited data exists regarding risk factors for adverse outcomes in older adults hospitalized with Community-Acquired Pneumonia (CAP) in low- and middle-income countries such as India. This multisite study aimed to assess outcomes and associated risk factors among adults aged ≥60 years hospitalized with pneumonia.

Methods: Between December 2018 and March 2020, we enrolled ≥60-year-old adults admitted within 48 hours for CAP treatment across 16 public and private facilities in four sites.

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Article Synopsis
  • Understanding the genetic dynamics of human adenoviruses (HAdV) is crucial for managing outbreaks and creating effective interventions, as highlighted during the 2022-2023 outbreak in West Bengal.
  • Researchers sequenced the genomes of 24 samples and discovered a new recombinant strain combining features of type 3 and type 7 HAdV, suggesting recent mutations in India.
  • The study indicated that current strains of HAdV can evade host immunity and may lead to more severe respiratory infections, emphasizing the need for comprehensive genomic analysis to assess outbreak potential.
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Article Synopsis
  • The study estimates the economic impact of acute respiratory illnesses (ARIs) on adults aged 60 and older in India, focusing on costs associated with medical care and effective preventive measures like vaccines.
  • A total of 6016 participants were monitored over 1.5 years, revealing that pneumonia cases incurred higher costs, with a significant portion being indirect costs due to lost productivity.
  • The findings suggest urgent public health interventions are needed to reduce the burden of ARIs, particularly among vulnerable older adults, as annual costs average around $29.5 per person.
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Differential regulation of the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), which is considered the rate-limiting enzyme of the cholesterol biosynthesis pathway, has been reported in case of infection with many viruses. In our study, we have found that influenza virus infection decreases total cellular cholesterol level which is directly related to the downregulation of HMGCR protein. We found that HMGCR is degraded through ubiquitination and proteasomal-mediated pathway upon viral infection.

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Globally, different genotypes of human adenoviruses are associated with outbreaks of acute respiratory infection (ARI) though such evidence is lacking from India. In the present study, we report a sudden increase in the positivity of respiratory adenovirus among hospitalized children with ARI from Kolkata and the surrounding districts of West Bengal, India, from December 2022 to date. A sharp rise in the positivity rate of respiratory adenovirus was found which ranged from 22.

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Influenza A viruses (IAV) are fast-evolving pathogens with a very high mutation rate (2.0 × 10 to 2.0 × 10) compared to the influenza B (IBV) and influenza C (ICV) viruses.

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Antimicrobial resistance (AMR) is a major problem and an immediate alternative to antibiotics is the need of the hour. Research on the possible alternative products to tackle bacterial infections is ongoing worldwide. One of the most promising alternatives to antibiotics is the use of bacteriophages (phage) or phage-driven antibacterial drugs to cure bacterial infections caused by AMR bacteria.

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Bacterial infections continue to jeopardize human and animal health, impacting millions of lives by causing significant deaths every year. The use of antibiotics remains the primary choice of therapy and has only been partly successful in reducing the disease burden due to the evolving nature of resistant microbes. Widespread and inappropriate use of antibiotics resulted in the development of antibiotic-resistant microbial species provoking substantial economic burdens.

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Aim: To develop an accurate lab score based on in-hospital patients' potent clinical and biological parameters for predicting COVID-19 patient severity during hospital admission.

Methods: To conduct this retrospective analysis, a derivation cohort was constructed by including all the available biological and clinical parameters of 355 COVID positive patients (recovered = 285, deceased = 70), collected in November 2020-September 2021. For identifying potent biomarkers and clinical parameters to determine hospital admitted patient severity or mortality, the receiver operating characteristics (ROC) curve and Fischer's test analysis was performed.

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In addition to the ongoing global problem of healthcare-acquired infections, the COVID-19 pandemic continues to pose a serious threat to the health of the global population. This unprecedented pandemic situation has reinforced the need for the development of technologies that can curb the transmission of viruses among human beings and help to control the infection. Existing disinfection techniques using either ultraviolet light or harsh chemicals pose safety risks and are not suitable for use in the presence of humans.

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Cholera continues to be a major burden for developing nations, especially where sanitation, quality of water supply, and hospitalization have remained an issue. Recently, growing antimicrobial-resistant strains of underscores alternative therapeutic strategies for cholera. Bacteriophage therapy is considered one of the best alternatives for antibiotic treatment.

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Purpose: We describe here a multicentric community-dwelling cohort of older adults (60 years of age) established to estimate incidence, study risk factors, healthcare utilisation and economic burden associated with influenza and respiratory syncytial virus (RSV) in India.

Participants: The four sites of this cohort are in northern (Ballabgarh), southern (Chennai), eastern (Kolkata) and western (Pune) parts of India. We enrolled 5336 participants across 4220 households and began surveillance in July 2018 for viral respiratory infections with additional participants enrolled annually.

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Coronavirus disease 2019 (COVID-19) is considered as the most dreaded disease that has spread all over the world in the recent past. Despite its outbreak in December 2019-January 2020, a few continents and countries such as India started to experience a significant number of COVID-19-positive cases from March 2020. GISAID clade variation analysis in the period March 2020-February 2021 (period I) and March 2021-first week of April 2021 (period II) showed a rapid variation of SARS-CoV-2 in all continents and India over time.

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Background: Cholera is a primordial disease caused by which existed from centuries in different parts of the world and still shows its periodic, endemic and epidemic presence. Thousands of cholera cases are reported from different parts of India and the disease remains endemic throughout the year. At present, we do not have enough knowledge about the phenotypic nature of the circulating strains in this part of the world.

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The last century has witnessed several assaults from RNA viruses, resulting in millions of death throughout the world. The 21st century appears no longer an exception, with the trend continued with escalated fear of SARS coronavirus in 2002 and further concern of influenza H5N1 in 2003. A novel influenza virus created the first pandemic of the 21st century, the pandemic flu in 2009 preceded with the emergence of another deadly virus, MERS-CoV in 2012.

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An analytical and cold model study of a prototype extended vane rod-type RFQ (radio frequency quadrupole linac) is presented. The bead-pull measurement allowed us to experimentally determine the effect of shaping of the vane-supporting posts and, most interestingly, the size of the vacuum enclosure in the dipolar and quadrupolar field asymmetry. Disk shaped beads of BaTiO have been tailor made for this purpose.

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In this experimental work we report our findings about a cascade () transition 5→5→5 of both atoms under different laser detuning combinations. The relative power levels of two individual lasers are adjusted under a counter-propagating configuration so that the system exhibits Autler-Townes splitting (ATS). However, the ATS, which is otherwise difficult to detect in a room-temperature alkali vapor cell offering large Doppler background, is well resolved here by using a combination of modulation transfer and phase-sensitive detection techniques.

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Annual flu led by influenza viruses is contemplated to be one of the foremost global health challenges due to its rapid spread leading to the life-threatening epidemic or pandemic. An enormous number of people die due to flu and its associated intricacies every year. Annual vaccination is considered to be the gold standard strategy to protect the individual from acquiring infection and further decimation, although recent estimates suggest that overall flu vaccine effectiveness was within 19% to 53% in last five years.

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PB1-F2 is a multifunctional protein and contributes to the pathogenicity of influenza A viruses. PB1-F2 is known to have strain and cell specific functions. In this study we have investigated the apoptotic and inflammatory responses of PB1-F2 protein from influenza viruses of diverse pathogenicities in A549 lung epithelial cells.

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Objectives: We have isolated a total of five newer cholera phages which are novel broad host range to incorporate with the existing phage typing schemes for an extended typing scheme.

Materials And Methods: These newly isolated phages were well characterized including the electron micrograph. A total of 300 strains were isolated from the different endemic region in India were included in phage typing study.

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In this work, we address the issue of the suitability of blue fluorescent light as a frequency offset reference during the ladder-level excitation 5S→5P→5D of Rb85 atoms. A simple pump-probe spectroscopy experiment is performed to generate non-degenerate blue light emission produced by the spontaneous decay route 5D→6P→5S. By varying the relative intensity of the pump-probe combination, we can hover between regimes dominated by mechanisms such as double resonance optical pumping (DROP) and Autler-Townes splitting.

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In this experimental work, we address the issue of the control of two-photon absorption in a Doppler broadened medium of Rb85 atoms under the ladder level coupling 5S→5P→5D. Here, suppression and enhancement of two-photon absorption are executed by applying an auxiliary laser beam, which is not physically propagating in the same line of the pump-probe combination. Instead, the auxiliary beam, which is in resonance with the Rb85 D transition, is at a finite distance from the line of propagation of the pump-probe combination.

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Radioactive ion beams of In (indium-111, half-life 2.8 days) have been produced using the plasma sputtering method in an electron cyclotron resonance (ECR) ion source at the Variable Energy Cyclotron Centre RIB facility. Indium isotopes were first produced by bombarding a natural silver target with a 32 MeV, 40 μA alpha particle beam from the K-130 cyclotron.

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High-fat diet (HFD) elevates circulatory fatty acids and influences glucose and fat metabolism. Azelaic acid (AzA), a naturally occurring α,ω-dicarboxylic acid in wheat, rye, barley, oat seeds and sorghum, has been reported to exert antidiabetic effects in HFD-induced type 2 diabetes mellitus (T2DM) C57BL/6J mice. The present study was undertaken to identify the genes that are differentially modulated by treatment with AzA in HFD-fed mice.

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