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Sourav Sen

    Sourav Sen

    India has become the third worst-hit nation by the COVID-19 pandemic caused by the SARS-CoV-2 virus. Here, we investigated the molecular, phylogenomic, and evolutionary dynamics of SARS-CoV-2 in western India, the most affected region of... more
    India has become the third worst-hit nation by the COVID-19 pandemic caused by the SARS-CoV-2 virus. Here, we investigated the molecular, phylogenomic, and evolutionary dynamics of SARS-CoV-2 in western India, the most affected region of the country. A total of 90 genomes were sequenced. Four nucleotide variants, namely C241T, C3037T, C14408T (Pro4715Leu), and A23403G (Asp614Gly), located at 5’UTR, Orf1a, Orf1b, and Spike protein regions of the genome, respectively, were predominant and ubiquitous (90%). Phylogenetic analysis of the genomes revealed four distinct clusters, formed owing to different variants. The major cluster (cluster 4) is distinguished by mutations C313T, C5700A, G28881A are unique patterns and observed in 45% of samples. We thus report a newly emerging pattern of linked mutations. The predominance of these linked mutations suggests that they are likely a part of the viral fitness landscape. A novel and distinct pattern of mutations in the viral strains of each of...
    BACKGROUND In an infection caused by multidrug-resistant Enterobacteriaceae, carbapenems is one the last antibiotics used, but the carbapenemase producing Enterobacteriaceae pose a clinical challenge. A relatively new test which was... more
    BACKGROUND In an infection caused by multidrug-resistant Enterobacteriaceae, carbapenems is one the last antibiotics used, but the carbapenemase producing Enterobacteriaceae pose a clinical challenge. A relatively new test which was described few years back known as modified carbapenem inactivation method (mCIM) is used to detect the presence of carbapenemase activity in Gramnegative bacilli. Various studies show this test be to be very sensitive and specific. We aim to study mCIM positivity on samples which are positive by Kirby-Bauer disk diffusion antibiotic sensitivity test method used for detection of carbapenem resistant Enterobacteriaceae (CRE) from clinical specimens. METHODS The study is a cross sectional descriptive study conducted in a tertiary care hospital. Samples received from February 2019 to September 2019 were included in the study. During this period 150 samples were collected which were resistant to meropenem by Kirby-Bauer disk diffusion method. These CREs isola...
    Background. Aspergillus is an inherently ubiquitous, weakly pathogenic fungus causing opportunistic infections. It is very rarely localized in the larynx, although laryngeal Aspergillosis may develop in the immunocompromised patients... more
    Background. Aspergillus is an inherently ubiquitous, weakly pathogenic fungus causing opportunistic infections. It is very rarely localized in the larynx, although laryngeal Aspergillosis may develop in the immunocompromised patients including those with leukaemia and severe aplastic anaemia. Objective. The aim of the research was to explore the primary laryngeal Aspergillosis in an immunocompetent patient thru a case report. Methods. A case report of primary laryngeal Aspergillosis in an immunocompetent patient is presented. Results. A male patient of 40 years old, presenting with chronic worsening hoarseness, was found to have a smooth, white spheroid submucosal growth on left vocal cord with preserved bilateral cord movements on videostroboscopy. Histopathological examination of vocal cord growth revealed squamous epithelium containing septate hyphae with acute angle dichotomous branching pattern consistent with Aspergillus. Voice improved after a four-week course of oral itracon...
    The objective of this review was to assess the burden of HIV drug resistance mutations (DRM) in Indian adults exposed to first-line antiretroviral therapy (ART) as per national guidelines. An advanced search of the published literature on... more
    The objective of this review was to assess the burden of HIV drug resistance mutations (DRM) in Indian adults exposed to first-line antiretroviral therapy (ART) as per national guidelines. An advanced search of the published literature on HIV drug resistance in India was performed in the PubMed and Scopus databases. Data pertaining to age, sex, CD4 count, viral load, and prevalence of nucleoside reverse transcriptase inhibitor (NRTI)/non-nucleoside reverse transcriptase inhibitor (NNRTI) DRM were extracted from each publication. Year-wise Indian HIV-1 reverse transcriptase (RT) sequences were retrieved from the Los Alamos HIV database and mutation analyses were performed. A time trend analysis of the proportion of sequences showing NRTI resistance mutations among individuals exposed to first-line ART was conducted. Overall, 23 studies (1046 unique RT sequences) were identified indicating a prevalence of drug resistance to NRTI and NNRTI. The proportion of RT sequences with any DRM, ...
    Introduction. In India, 4,86,173 HIV infected patients are on first line antiretroviral therapy (ART) as of January 2012. HIV drug resistance (HIVDR) is drug and regimen-specific and should be balanced against the benefits of providing a... more
    Introduction. In India, 4,86,173 HIV infected patients are on first line antiretroviral therapy (ART) as of January 2012. HIV drug resistance (HIVDR) is drug and regimen-specific and should be balanced against the benefits of providing a given ART regimen. Material & Methods. The emergence of HIVDR mutations in a cohort of 100 consecutive HIV-1 infected individuals attending ART centre, on first line ART for 12 months, was studied. CD4(+) T-cell counts and plasma HIV-1 RNA level were determined. Result. Out of the 100 HIV-1 infected individuals, 81 showed HIVDR prevention (HIV-1 RNA level < 1000/mL), while the remaining 19 had HIV-1 viral RNA level > 1000/mL. HIVDR genotyping was carried out for individuals with evidence of virologic failure (HIV-1 RNA level > 1000/mL). The most frequent NRTI-associated mutation observed was M184V, while K103N/S was the commonest mutation at NNRTI resistance position. Conclusion. Our study has revealed the emergence of HIVDR in HIV-1 infect...
    Several studies have shown aggregation of autoimmune thyroiditis in families by estimation of thyroid antibodies. However, the prevalence by concurrent estimation with fine-needle aspiration cytology (FNAC) and thyroid antibodies has not... more
    Several studies have shown aggregation of autoimmune thyroiditis in families by estimation of thyroid antibodies. However, the prevalence by concurrent estimation with fine-needle aspiration cytology (FNAC) and thyroid antibodies has not been previously reported. We therefore studied 222 first-degree relatives (group 1) of 71 index cases diagnosed as lymphocytic thyroiditis on FNAC and 81 family members (group 2) of 23 goitrous children diagnosed as colloid goiter on FNAC for comparison. Successful FNAC conducted in 122 group 1 subjects revealed lymphocytic thyroiditis in 51 (42%), whereas lymphocytic thyroiditis was diagnosed in only 5 goitrous subjects (13%) in group 2. Among group 1 subjects with FNAC-proven lymphocytic thyroiditis, antithyroid peroxidase (TPO) antibodies were found in 35 (67%), while in anti-TPO antibody positive goitrous relatives of group 1, lymphocytic thyroiditis was found in 36 (78%). Eight new cases of overt hypothyroidism and 45 new cases of subclinical hypothyroidism were diagnosed among group 1 subjects. Our study suggests: (1). familial clustering of autoimmune thyroiditis; (2). if only FNAC or thyroid antibodies is used for diagnosis of autoimmune thyroiditis in children, 22%-33% of cases are likely to be missed; and (3). serum thyrotropin (TSH) should be offered to all first-degree relatives of patients with juvenile autoimmune thyroiditis.
    While antiretroviral drugs, those approved for clinical use and others under evaluation, attempt in lowering viral load and boost the host immune system, antiretroviral drug resistance acts as a major impediment in the management of human... more
    While antiretroviral drugs, those approved for clinical use and others under evaluation, attempt in lowering viral load and boost the host immune system, antiretroviral drug resistance acts as a major impediment in the management of human immune deficiency virus type-1 (HIV-1) infection. Antiretroviral drug resistance testing has become an important tool in the therapeutic management protocol of HIV-1 infection. The reliability and clinical utilities of genotypic and phenotypic assays have been demonstrated. Understanding of complexities of interpretation of genotyping assay, along with updating of lists of mutation and algorithms and determination of clinically relevant cut-offs for phenotypic assays are of paramount importance. The assay results are to be interpreted and applied by experienced HIV practitioners, after taking into consideration the clinical profile of the patient. This review sums up the methods of assay currently available for measuring resistance to antiretrovira...