Publications by authors named "Narendrakumar Lekshmi"

Delta and Omicron variants of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are remarkably contagious, and have been recognized as variants of concern (VOC). The acquisition of spontaneous substitutions or insertion-deletion mutations (indels) in the spike protein-encoding gene substantially increases the binding affinity of the receptor binding domain (RBD)-hACE2 complex and upsurges the transmission of both variants. In this study, we analyzed thousands of genome sequences from 30 distinct SARS-CoV-2 variants, focusing on the unique nucleic acid signatures in the spike gene specific to the Delta and Omicron variants.

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Antibiotics, which hit the market with astounding impact, were once called miracle drugs, as these were considered the ultimate cure for infectious diseases in the mid-20th century. However, today, nearly all bacteria that afflict humankind have become resistant to these wonder drugs once developed to stop them, imperiling the foundation of modern medicine. During the COVID-19 pandemic, there was a surge in macrolide use to treat secondary infections and this persistent use of macrolide antibiotics has provoked the emergence of macrolide resistance.

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Microbes evolve rapidly by modifying their genomes through mutations or through the horizontal acquisition of mobile genetic elements (MGEs) linked with fitness traits such as antimicrobial resistance (AMR), virulence, and metabolic functions. We conducted a multicentric study in India and collected different clinical samples for decoding the genome sequences of bacterial pathogens associated with sepsis, urinary tract infections, and respiratory infections to understand the functional potency associated with AMR and its dynamics. Genomic analysis identified several acquired AMR genes (ARGs) that have a pathogen-specific signature.

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β-lactam antibiotics are one of the most widely used and diverse classes of antimicrobial agents for treating both Gram-negative and Gram-positive bacterial infections. The β-lactam antibiotics, which include penicillins, cephalosporins, monobactams and carbapenems, exert their antibacterial activity by inhibiting the bacterial cell wall synthesis and have a global positive impact in treating serious bacterial infections. Today, β-lactam antibiotics are the most frequently prescribed antimicrobial across the globe.

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One of the fascinating outcomes of human microbiome studies adopting multi-omics technology is its ability to decipher millions of microbial encoded functions in the most complex and crowded microbial ecosystem, including the human gastrointestinal (GI) tract without cultivating the microbes. It is well established that several functions that modulate the human metabolism, nutrient assimilation, immunity, infections, disease severity and therapeutic efficacy of drugs are mostly of microbial origins. In addition, these microbial functions are dynamic and can disseminate between microbial taxa residing in the same ecosystem or other microbial ecosystems through horizontal gene transfer.

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Objectives: The emergence of multidrug-resistant Staphylococcus aureus strains is mainly mediated by mobile genetic elements, such as Staphylococcal Cassette Chromosome mec (SCCmec). Currently, SCCmec elements in S. aureus are classified into 15 types, with type IV being the most common in hospital and community-associated methicillin-resistant S.

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Article Synopsis
  • The respiratory system contains a diverse range of microorganisms, including bacteria, viruses, and fungi, which play a critical role in respiratory health and immunity.
  • The balance of these microbes, known as microbiota, is essential for maintaining healthy respiratory function, while disturbances can lead to immune responses and infections, such as pneumonia.
  • The chapter highlights key microbial groups in the respiratory system and discusses effective strategies to prevent pneumonia by managing the respiratory microbiome.
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The goldfish hematopoietic necrosis viral disease (GHNVD) has led to worldwide economic losses in goldfish aquaculture. The present study has focused on the development of an inactivated vaccine for the cyprinid herpesvirus (CyHV-2) and to check the immunogenicity of the vaccine in the host. The fantail goldfish fin (FtGF) cell line was used in the propagation of the CyHV-2 and the viral titer obtained were of 10 TCID/ml.

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Tilapia lake virus (TiLV) and Lactococcus garvieae are 2 major pathogens of cultured Nile tilapia Oreochromis niloticus. In June-July 2018, a disease outbreak was reported in Nile tilapia cultured in brackish water floating cages in Kerala, India. Affected fish died gradually, and cumulative mortality reached ~75% within 1 mo.

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Vibrio vulnificus is a Gram negative motile bacterium known to cause fatal septicaemia and wound infection. It is commonly associated with the consumption of under-cooked seafood or exposure to marine environment. We report a case of a 55 year old male patient, who was presented with right lower limb cellulitis and septicaemia due to V.

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: COVID-19 infection with no known-specific drugs or vaccines has impacted mankind and has become beyond precedence. Currently, re-purposing of existing drugs is the only therapeutic option for managing COVID-19 symptoms and associated co-infections to reduce mortality. Antimicrobials as varied as antiparasitic, antiviral, and antibiotics are under various stages of evaluation.

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Vibrios have been identified to cause extra-intestinal complications apart from the occasional cholera-like diarrhoeal outbreaks. The non-O1/O139 Vibrio cholerae strains are ubiquitous in environmental water bodies and hence pose a threat to people even without obvious risk factors. We describe a case of sepsis in a child with spinal dysraphism caused by a V.

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Vibrio cholerae, causative agent of the water-borne disease cholera still threatens a large proportion of world's population. The major biotypes of the pathogen are classical and El Tor. There have been recent reports of variant V.

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Cholera, caused by the Gram-negative bacterium Vibrio cholerae, remains a serious threat in underdeveloped countries. Although rehydration therapy has been the mainstay of disease management, antibiotics are also being used as an adjunct treatment, resulting in an increase in the circulation of antimicrobial-resistant V. cholerae strains.

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Article Synopsis
  • Cholera, caused by a Gram-negative bacterium, is a significant health issue in developing countries due to its easy spread and resistance to multiple drugs.
  • The study explores new strategies to fight the disease, particularly focusing on inhibiting biofilms, which protect bacteria and reduce the effectiveness of antibiotics.
  • Tryptanthrin, a phytochemical found to have strong anti-biofilm effects at low concentrations, targets a protein called LuxO and works well with the antibiotic ciprofloxacin, highlighting its potential as a novel treatment approach.
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Background: Enterococcus faecalis is a major clinically relevant nosocomial bacterial pathogen frequently isolated from polymicrobial infections. The biofilm forming ability of E. faecalis attributes a key role in its virulence and drug resistance.

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Cholera, caused by the Gram-negative bacterium , remains a major problem in developing countries. Although the disease can be managed by oral rehydration therapy, antibiotics are widely used nowadays to treat the disease. However, chemoprophylaxis has been proven to have no effect on the spread of the disease, but acts as a major driver for antimicrobial resistance (AMR).

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Objectives: Multidrug-resistant (MDR) Klebsiella pneumoniae isolates with colistin resistance are a major concern in healthcare settings. This study aimed to evaluate the genome-wide distribution of antimicrobial resistance genes in K. pneumoniae CRKP I with high colistin resistance isolated from a patient in India.

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is recognized as one of the leading pathogens causing nosocomial infections. Here we report a draft genome sequence of SK460, isolated from a chronic diabetic foot ulcer patient. This strain exhibits various biofilm-associated genes, virulence genes, and antibiotic-resistance genes related to aminoglycoside, macrolide, and tetracycline resistance.

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We report here the draft genome sequence of a Haitian variant strain, W4-13, isolated from Kerala, South India, possessing cholera toxin gene in chromosomes I and II. The sequence will be useful to achieve a profound understanding on its evolution, with emphasis on its pathogenesis and antibiotic resistance.

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