Browsing by Author "Samer Singh"

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A novel nanotherapeutic approach: Dual action of green-synthesized silver nanoparticles from Clerodendrum serratum against MDR-ESKAPE pathogens with wound healing potential
(Editions de Sante, 2025) Ritu Raj Patel; Pandey Priya Arun; Vidyasagar; Aradhana Mishra; Sudhir Kumar Singh; Samer Singh; Brahmeshwar Mishra; Meenakshi Singh
The rapid emergence of multidrug-resistant (MDR) ESKAPE pathogens in healthcare settings, particularly chronic wound infections presents a critical challenge. Moreover, with antibiotic resistance reaching alarming levels and conventional treatments failing against biofilm-associated infections, there is an urgent need to develop novel and effective therapeutic strategies. In this study, silver nanoparticles (AgNPs) synthesized via a green method using Clerodendrum serratum leaf extract, along with their polyethylene glycol-coated derivative (PEG-AgNPs), were evaluated for their antibacterial and wound-healing potential. PEG-AgNPs demonstrated superior antibacterial efficacy, with significantly lower minimum inhibitory concentration (MIC) values (0.3906–12.5 μg/mL) compared to AgNPs (3.125–25 μg/mL). Time-kill studies further confirmed that PEG-AgNPs exhibited enhanced bactericidal properties. Mechanistic investigations revealed that their antibacterial activity resulted from bacterial cell membrane rupture, leading to cytoplasmic content leakage, as confirmed by FACS analysis. Furthermore, biofilm formation by these pathogens was evaluated, and the nanoparticles demonstrated remarkable anti-biofilm potency, particularly against Acinetobacter baumannii and Pseudomonas aeruginosa. The LC-MS analysis of C. serratum leaf extract revealed bioactive phytoconstituents, which were subjected to molecular docking studies against biofilm-forming factors in P. aeruginosa and A. baumannii confirming strong binding interactions. Additionally, the prepared nanoparticle-based gel formulations significantly enhanced in vivo wound healing in both uninfected and infected (A. baumannii and P. aeruginosa) wounds, highlighting their potential as dual-action therapeutic agents for inhibiting MDR pathogens and simultaneously promoting tissue regeneration. Therefore, these findings suggest that green synthesized nanoparticles, particularly PEG-AgNPs hold promise as novel interventions for combating MDR-ESKAPE infected wounds. © 2025 Elsevier B.V.
A squalene oil emulsified MPL-A and anti-CD200/CD300a antibodies adjuvanted whole-killed Leishmania vaccine provides durable immunity against L. donovani parasites
(Elsevier Ltd, 2024) Baishakhi Mahapatra; Abhishek Singh; Arpita Banerjee; Shruti Sirohi; Samer Singh; Vikash K. Dubey; Rakesh K. Singh
Antigenic inefficacy to induce robust immune responses and durable memory are major causes of constantly failing prophylactic approaches in leishmaniasis. Here, we determine the potential of a standardized whole-killed Leishmania vaccine (Leishvacc) adjuvanted with anti-CD200 and anti-CD300a antibodies, either alone or with monophosphoryl lipid A (MPL-SE) emulsified in squalene oil, in restoring the compromised antigen presenting abilities of dendritic cells (DCs), effector properties of CD4+T cells and providing protection against Leishmania donovani parasites. In animals vaccinated with antibodies adjuvanted vaccines, either alone or with MPL-SE, the antigen presenting abilities of CD11c+ DCs against Leishmania antigens, measured in terms of CD80, CD86, MHC-I, and MHC-II surface receptors and intracellular IL-12 were found enhanced than non-adjuvanted vaccine. We observed more proliferative and pro-inflammatory cytokines i.e. IL-2, IFN-γ, IL-23, and IL-12 producing CD4+T cells in antibodies/MPL-SE adjuvanted vaccinated animals further suggesting that this approach helps antigen activated CD4+T cells to acquire pro-inflammatory cytokines producing abilities. In antibodies, either alone or with MPL-SE, vaccinated animals, the number of CD4+ central memory T cells and their longevity were found significantly enhanced that further evidenced the impact of this vaccination approach in inducing long term protective immunity. The animals, receiving antibodies adjuvanted vaccines, either alone or with MPL-SE, exhibited excellent protection against virulent parasites by restricting their growth, which correlated with the significantly reduced parasitemia, splenomegaly, and hepatomegaly, along with fewer numbers of liver granulomas. Our findings provide an insight to a new immunoprophylactic approach against visceral leishmaniasis, which not only satisfies the safety criteria, but also provides a robust immunogenic response with remarkable potential for parasites control. However, further in-depth investigations are needed to ascertain its ability in inducing long-lasting immunity. © 2024
Adjuvantation of whole-killed Leishmania vaccine with anti-CD200 and anti-CD300a antibodies potentiates its efficacy and provides protection against wild-type parasites
(Elsevier Ltd, 2023) Rajan Singh; Anshul Anand; Baishakhi Mahapatra; Shashi Saini; Abhishek Singh; Samer Singh; Vinod Kumar; Pradeep Das; Sangram Singh; Rakesh K. Singh
One of the major reasons behind the limited success of vaccine candidates against all forms of leishmaniasis is the inability of parasitic antigens to induce robust cell-mediated immunity and immunological memory. Here we find, for the first time, that the adjuvantation of whole-killed Leishmania vaccine (Leishvacc) with anti-CD200 and anti-CD300a antibodies enhances CD4+ T cells mediated immunity in vaccinated mice and provides protection against wild-type parasites. The antibody adjuvantation, either alone or with a TLR4 agonist monophosphoryl A (MPL-A), induced the production of pro-inflammatory cytokines viz., IFN-γ, TNF-α, and IL-2 by antigen experienced CD4+ T cells, and also enhanced their rate of conversion into their memory phenotypes against Leishvacc antigens. The antibody adjuvanted vaccine also promoted the generation of IgG2a-mediated protective humoral immunity in vaccinated mice. Further, the mice vaccinated with antibodies adjuvanted vaccine showed strong resilience against metacyclic forms of L. donovani parasites as we observed reduced clinical features such as splenomegaly, hepatomegaly, granulomatous tissues in the liver, and parasitic load in their spleen. The findings of this study demonstrate that the anti-CD200 and anti-CD300a antibodies have potential to increase the protective efficacy of the whole-killed Leishmania vaccine, and opens up a new gateway to diversify the roles of immune checkpoints in vaccine development against leishmaniasis. © 2023 Elsevier Ltd
Anthrax prevention through vaccine and post-exposure therapy
(Taylor and Francis Ltd., 2020) Manish Manish; Shashikala Verma; Divya Kandari; Parul Kulshreshtha; Samer Singh; Rakesh Bhatnagar
Introduction: Vaccines and therapeutic antibodies are the most crucial components of anthrax prophylaxis (pre- and post-exposure) and treatment. The improvement in the availability and safety profile of vaccines and the therapeutic antibodies has helped immensely in reducing the worldwide burden of anthrax. Areas covered: Current recommendations for anthrax prophylaxis and control, vaccines and therapeutic antibodies, the recent endeavors, particularly, made after 2010 toward making them safer and more efficacious along with our opinion on its future course. Primarily, PubMed and Europe PMC were searched to cover the recent developments in the above-indicated areas. Expert opinion: Some key existing lacunae in our understanding of the working of biologicals-based anthrax-control measures, i.e., vaccines and therapeutic antibodies, should be addressed to improve their overall stability, safety profile, and efficacy. The identification of novel inhibitors targeting different key-molecules and vital-steps contributing to the overall anthrax pathophysiology could make a difference in anthrax control. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
Antigens activated SOCS3+CD200R+CD4+ T cells are critical to Leishmania pathogenesis and a distinctive target for vaccine development
(Elsevier Ltd, 2025) Abhishek Kumar Singh; Baishakhi Mahapatra; Ankita Srivastava; Samer Singh; Pradeep Kumar Das; Rakesh Kumar Singh
The expression of suppression of cytokine signalling protein (SOCS3) has been posited as a critical determinant of T cells differentiation and maturation during visceral leishmaniasis (VL), however, the antigen-activated CD4+ T cell phenotypes expressing this protein have not been explored much. Since, the inherent nature of SOCS3 protein directs the polarization of CD4+ T cells towards anti-inflammatory Th2 axis, the identification of SOCS3 expressing T-cell phenotypes will provide a better understanding on Leishmania immunobiology. Our previous findings have delineated a distinct Leishmania antigens activated CD4+ T cells phenotype expressing CD200R receptor that acts as prime anti-inflammatory disease promoting subset. Here, in this study we observed that the SOCS3+ antigen activated CD200R+CD4+ T cells phenotype is succinctly involved in cytokines regulation during Leishmania infection. We further observed that CD200R+CD4+ T cells expressing higher levels of SOCS3 protein have the potential to polarize these cells to produce more IL-10, and less IL-12 & IFN-γ as compared to CD200R−CD4+T cells on exposure to whole killed Leishmania vaccine in a mice model of VL. Furthermore, the observed decline in splenic SOCS3 expression along with inflammatory factors like prostaglandin E2, upon abrogation of CD200R signalling in Leishmania infected animals suggest a coordinated role of CD200R and SOCS3 protein in VL pathogenesis. These findings prompted us to study the potential of CD200R and SOCS3 in the vaccine-induced immunity. Immunization with an in-house whole killed Leishmania vaccine adjuvanted with anti-CD200 antibodies not only reduced splenic SOCS3 expression but also enhanced CD4+ T cells' effector functions and their memory conversion. The down-regulation of splenic SOCS3 was also found correlated with reduced granuloma and parasitic load in SOCS3-low mice groups. Hence, the identified SOCS3+CD200R+CD4+ T cells subset reveals a potential disease-promoting phenotype that can be targeted to enhance the immunogenicity of Leishmania antigens. © 2025
Antimicrobials and Antibiotic Resistance Genes in Water Bodies: Pollution, Risk, and Control
(Frontiers Media S.A., 2022) Ashish Kumar Singh; Rajinder Kaur; Shashikala Verma; Samer Singh
The manuscript endeavors to provide a perspective on the role of water bodies in the spread of antimicrobial (antibiotic) resistance (AMR), antimicrobial resistant bacteria (ARB), and antimicrobial resistance genes (ARGs) among pathogens, animals, and humans. We briefly indicate how the AMR problem is globally affecting public health, along with strategies and mechanisms to combat the dissemination of ARB and ARGs. A brief systematic survey of the literature (2015-onwards) for the presence of antimicrobial residues and the occurrence of ARGs and antimicrobial resistant microorganisms in different water bodies/sources indicates the gravity of the situation and suggests their important role in the occurrence and spread of AMR, ARB, and ARGs. The prevalent water treatment methods which tend to reduce ARB and ARGs from water resources are unable to remove them completely, allowing the problem of AMR to continue and spread to organisms of concern. In this opinion article, we attempt to underline the key role of controlling the release/discharge of antimicrobial contaminants in water bodies and their buildup in checking the development and spread of AMR. The reduction in the release of antibiotic residues in the environment, especially water bodies, combined with the development of improved surveillance means and efficacious treatment/removal/decomposition methods could help curb the menace of AMR effectively. We suggest the expansion of the ambit of ‘One Health Approach to AMR crises proposed by the World Bank, 2021 to include the ‘reduction of antimicrobial contamination of the environment’ as the ‘seventh domain’ of activity to effectively achieve its objective. Copyright © 2022 Singh, Kaur, Verma and Singh.
BCG vaccination policy, natural boosting and pediatric brain and CNS tumor incidences
(Frontiers Media S.A., 2023) Samer Singh; Amita Diwakar; Rakesh K. Singh
Bacille Calmette-Guérin (BCG) vaccination supposedly imparts and augments “trained immunity” that cross-protects against multiple unrelated pathogens and enhances general immune surveillance. Gradual reductions in tuberculosis burden over the last 3–5 decades have resulted in the withdrawal of BCG vaccination mandates from developed industrialized countries while reducing to a single neonatal shot in the rest. Concurrently, a steady increase in early childhood Brain and CNS (BCNS) tumors has occurred. Though immunological causes of pediatric BCNS cancer are suspected, the identification of a causal protective variable with intervention potential has remained elusive. An examination of the countries with contrasting vaccination policies indicates significantly lower BCNS cancer incidence in 0–4-year-olds (per hundredthousand) of countries following neonatal BCG inoculations (n=146) vs. non-BCG countries (n=33) [Mean: 1.26 vs. 2.64; Median: 0.985 vs. 2.8; IQR: 0.31–2.0 vs. 2.4–3.2; P=<0.0001 (two-tailed)]. Remarkably, natural Mycobacterium spp. reexposure likelihood is negatively correlated with BCNS cancer incidence in 0-4-year-olds of all affected countries [r(154): −0.6085, P=<0.0001]. Seemingly, neonatal BCG vaccination and natural “boosting” are associated with a 15–20-fold lower BCNS cancer incidence. In this opinion article, we attempt to synthesize existing evidence implying the immunological basis of early childhood BCNS cancer incidence and briefly indicate possible causes that could have precluded objective analysis of the existing data in the past. We draw the attention of the stakeholders to consider the comprehensive evaluation of immune training as a potential protective variable through well-designed controlled clinical trials or registry-based studies as feasible for its potential applications in reducing childhood BCNS cancer incidence. Copyright © 2023 Singh, Diwakar and Singh.
CD300a Receptor Blocking Enhances Early Clearance of Leishmania donovani From Its Mammalian Host Through Modulation of Effector Functions of Phagocytic and Antigen Experienced T Cells
(Frontiers Media S.A., 2022) Rajan Singh; Anshul Anand; Arun K. Rawat; Shashi Saini; Baishakhi Mahapatra; Naveen K. Singh; Alok K. Mishra; Samer Singh; Nisha Singh; Dhiraj Kishore; Vinod Kumar; Pradeep Das; Rakesh K. Singh
The parasites of the genus Leishmania survive and proliferate in the host phagocytic cells by taking control over their microbicidal functions. The parasite also promotes differentiation of antigen-specific anti-inflammatory cytokines producing effector T cells, which eventually results in disease pathogenesis. The mechanisms that parasites employ to dominate host adaptive immunity are largely unknown. For the first time, we report that L. donovani, which causes visceral leishmaniasis in the Indian subcontinent, upregulates the expression of an immune inhibitory receptor i.e., CD300a on antigen presenting and phagocytic cells to dampen their effector functions. The blocking of CD300a signals in leishmania antigens activated macrophages and dendritic cells enhanced the production of nitric oxide, pro-inflammatory cytokines along with MHCI/II genes expression, and reduced parasitic uptake. Further, the abrogation of CD300a signals in Leishmania infected mice benefited antigen-experienced, i.e., CD4+CD44+ and CD8+CD44+ T cells to acquire more pro-inflammatory cytokines producing phenotypes and helped in the early clearance of parasites from their visceral organs. The CD300a receptor blocking also enhanced the conversion of CD4+ T effectors cells to their memory phenotypes i.e., CCR7high CD62Lhigh up to 1.6 and 1.9 fold after 14 and 21 days post-infection, respectively. These findings implicate that CD300a is an important determinant of host phagocytic cells functions and T cells differentiation against Leishmania antigens. Copyright © 2022 Singh, Anand, Rawat, Saini, Mahapatra, Singh, Mishra, Singh, Singh, Kishore, Kumar, Das and Singh.
Clinicopathological analysis and demographic features of ocular malignancies
(Dove Medical Press Ltd, 2021) Abdullah Al-Mujaini; Rajendra Prakash Maurya; Sanjay Bosak; Manish Kumar Karan; Meghna Roy; Virendra Pratap Singh; Mahendra Kumar Singh; Ajay Kumar; Samer Singh
Objective: This study aimed to evaluate the epidemiological and clinicopathological spec-trum of ocular malignancies among patients presenting to a teaching hospital in Northern India. Methods: A total of 246 histopathologically diagnosed patients with ocular malignancies were included in the study. Tumor type and size, primary origin and location of tumor, clinical staging, radiological findings, histopathological type, and treatment outcomes were assessed. Results: Overall, males over 55 years of age were most commonly affected and the majority of cases were primary ocular or adnexal malignancies (n = 226; 91.87%). The eyelids and periocular structures (n = 92; 37.40%) were the most commonly involved site, followed by the orbit (n = 72; 29.27%), ocular surface (n = 46; 18.70%) and intraocular region (n = 36; 14.63%). The majority of the patients (n = 68; 27.64%) were managed by primary surgical excision and reconstruction. However, 46 patients (18.70%) with advanced lesions underwent neoadjuvant chemotherapy followed by surgical excision and more extensive orbital lesions were treated by exenteration followed by adjuvant chemotherapy (n=48; 19.51%), while patients with metastatic tumor were given palliative chemotherapy/external beam radiation therapy (n= 46; 18.70%). Overall, 45.12% of patients were cured completely, 15.45% showed a partial response to the treatment, 13.04% had progressive disease and 16.67% demonstrated disease recurrence. Conclusion: A clinicopathological analysis of ocular malignancies at a teaching hospital in Northern India indicated the preponderance of primary ocular malignancies, with eyelid sebaceous gland carcinomas being the most common pathological diagnosis. Most of our patients had advanced and extensive disease among them majority belonged to the rural background and poor socio-economic status. © 2021 Al-Mujaini et al.
Common garlic (Allium sativum L.) has potent Anti-Bacillus anthracis activity
(Elsevier Ireland Ltd, 2021) Rajinder Kaur; Atul Tiwari; Manish Manish; Indresh K. Maurya; Rakesh Bhatnagar; Samer Singh
Ethnopharmacological relevance: Gastrointestinal anthrax, a disease caused by Bacillus anthracis, remains an important but relatively neglected endemic disease of animals and humans in remote areas of the Indian subcontinent and some parts of Africa. Its initial symptoms include diarrhea and stomachache. In the current study, several common plants indicated for diarrhea, dysentery, stomachache or as stomachic as per traditional knowledge in the Indian subcontinent, i.e., Aegle marmelos (L.) Correa (Bael), Allium cepa L. (Onion), Allium sativum L. (Garlic), Azadirachta indica A. Juss. (Neem), Berberis asiatica Roxb. ex DC. (Daruharidra), Coriandrum sativum L. (Coriander), Curcuma longa L. (Turmeric), Cynodon dactylon (L.) Pers. (Bermuda grass), Mangifera indica L. (Mango), Morus indica L. (Black mulberry), Ocimum tenuiflorum L. (Ocimum sanctum L., Holy Basil), Ocimum gratissimum L. (Ram Tulsi), Psidium guajava L. (Guava), Zingiber officinale Roscoe (Ginger), were evaluated for their anti-Bacillus anthracis property. The usage of Azadirachta indica A. Juss. and Curcuma longa L. by Santals (India), and Allium sp. by biblical people to alleviate anthrax-like symptoms is well documented, but the usage of other plants is traditionally only indicated for different gastrointestinal disturbances/conditions. Aim of the study: Evaluate the above listed commonly available edible plants from the Indian subcontinent that are used in the traditional medicine to treat gastrointestinal diseases including those also indicated for anthrax-like symptoms for the presence of potent anti-B. anthracis activity in a form amenable to use by the general population in the endemic areas. Materials and methods: Aqueous extracts made from fourteen plants indicated above were screened for their anti-B. anthracis activity using agar-well diffusion assay (AWDA) and broth microdilution methods. The Aqueous Garlic Extract (AGE) that displayed most potent anti-B. anthracis activity was assessed for its thermostability, stability under pH extremes encountered in the gastrointestinal tract, and potential antagonistic interaction with bile salts as well as the FDA-approved antibiotics used for anthrax control. The bioactive fractions from the AGE were isolated by TLC coupled bioautography followed by their characterization using GC-MS. Results: Garlic (Allium sativum L.) extract was identified as the most promising candidate with bactericidal activity against B. anthracis. It consistently inhibited the growth of B. anthracis in AWDA and decreased the viable colony-forming unit counts in liquid-broth cultures by 6-logs within 6–12 h. The AGE displayed acceptable thermostability (>80% anti-B. anthracis activity retained on incubation at 50 °C for 12 h) and stability in gastric pH range (2–8). It did not antagonize the activity of FDA-approved antibiotics used for anthrax control. GC-MS analysis of the TLC separated bioactive fractions of AGE indicated the presence of previously unreported constituents such as phthalic acid derivatives, acid esters, phenyl group-containing compounds, steroids etc. Conclusion: The Aqueous Garlic Extract (AGE) displayed potent anti-B. anthracis activity. It was better than that displayed by Azadirachta indica A. Juss. (Neem) and Mangifera indica L., while Curcuma longa L. (Turmeric) did not show any activity under the assay conditions used. Further work should be undertaken to explore the possible application of AGE in preventing anthrax incidences in endemic areas. © 2020 Elsevier B.V.
Corrigendum to “Antigens activated SOCS3+CD200R+CD4+ T cells are critical to Leishmania pathogenesis and a distinctive target for vaccine development” [Vaccine 62 (2025) 127501] (Vaccine (2025) 62, (S0264410X25007984), (10.1016/j.vaccine.2025.127501))
(Elsevier Ltd, 2025) Abhishek Kumar Singh; Baishakhi Mahapatra; Ankita Srivastava; Samer Singh; Pradeep Kumar Das; Rakesh Kumar Singh
The authors regret the error in the acknowledgements in the published article (DOI: https://doi.org/10.1016/j.vaccine.2025.127501). The original text: This work is an output of a project funded to RKS by the Indian Council of Medical Research, New Delhi (No. VIR/12/2022/ECD-1). AS and BM are thankful to UP-CST, Lucknow, and DBT, New Delhi, respectively for their research fellowships. RKS also acknowledges the support received under the Institute of Eminence (IoE 6031), Central Government of India, and Uttar Pradesh council of science and technology (UP-CST/D-2245) for financial assistance. The corrected version: This work is an output of a project funded to RKS by the Indian Council of Medical Research, New Delhi (No. VIR/12/2022/ECD-1). AS and BM are thankful to UP-CST, Lucknow, and DBT, New Delhi, respectively for their research fellowships. RKS also acknowledges the support received under the Institute of Eminence (IoE 6031), Central Government of India, and Uttar Pradesh council of science and technology (UP-CST/D-2245) for financial assistance. PD, the recipient of ICMR-Emeritus Scientist, acknowledges the support of ICMR, New Delhi. This amendment ensures proper acknowledgement of contributions. We sincerely apologize for any inconvenience caused and thank the editors for their understanding. © 2025 Elsevier Ltd
Corrigendum to “Toxin-antitoxin systems in bacterial pathogenesis” [Heliyon Volume 9, Issue 4, April 2023, Article e14220] (Heliyon (2023) 9(4), (S2405844023014275), (10.1016/j.heliyon.2023.e14220))
(Elsevier Ltd, 2025) Sonika Sonika; Samer Singh; Saurabh S. Mishra; Shashikala Verma
In the original published version of this article, Reference [130] was incorrectly attributed to an unrelated study due to an oversight during revisions. This error arose from inadvertent misassociation with another publication by an author sharing the same last name and publication year. Original Version of Reference [130]:C.R. Garcia, J. Oliva, M.T. Romero, L.A. Diaz-Torres, Enhancing the photocatalytic activity of Sr4 Al14 O25: Eu(2+), Dy(3+) persistent phosphors by codoping with Bi(3+) ions, Photochem. Photobiol. 92 (2016) 231–237, https://doi.org/10.1111/php.12570. The citation has been revised to the correct one. The correct version of Reference [130] can be found below. Laura Fernández-García, Lucia Blasco, Maria Lopez, German Bou, Rodolfo García Contreras, Thomas Wood and María Tomas, Toxin-Antitoxin Systems in Clinical Pathogens, Toxins 2016, 8(7), 227, https://doi.org/10.3390/toxins8070227. The authors apologize for the errors. Both the HTML and PDF versions of the article have been updated to correct the errors. © 2025 The Author(s)
Cu-BTC metal organic framework (MOF) derived Cu-doped TiO2 nanoparticles and their use as visible light active photocatalyst for the decomposition of ofloxacin (OFX) antibiotic and antibacterial activity
(Elsevier B.V., 2021) Ramanpreet Kaur; Amandeep Kaur; Rajinder Kaur; Samer Singh; Manpreet Singh Bhatti; Ahmad Umar; S. Baskoutas; Sushil Kumar Kansal
Herein, we report the ultrasonic-assisted precipitation technique for the fabrication of Cu-doped TiO2 nanoparticles. The prepared sample showed high crystallinity, purity and nanoparticles like structure with the diameter in the range of 10–22 nm. The bandgap for Cu-doped TiO2 nanoparticles was estimated to be 2.91 eV using Tauc plot, which is considerable for improving the light-harvesting capacity. Further, the prepared Cu-doped TiO2 was used as photocatalyst for the eradication of ofloxacin (OFX), an antibiotic from an aqueous phase under visible illuminations. About 72% degradation of OFX (10 mg/L, pH 7) was achieved with Cu-doped TiO2 nanoparticles after 180 min of visible illumination. The probable photocatalytic mechanism for the decomposition of OFX has been proposed based on reactive species trapping study. Moreover, the antibiotic efficiency of OFX was investigated against Escherichia coli and it was observed that its antimicrobial activity was significantly diminished after the photocatalytic decomposition of the OFX solution with synthesized nanoparticles. © 2021 The Society of Powder Technology Japan
Distribution of Antibiotic-Resistant Enterobacteriaceae Pathogens in Potable Spring Water of Eastern Indian Himalayas: Emphasis on Virulence Gene and Antibiotic Resistance Genes in Escherichia coli
(Frontiers Media S.A., 2020) Ashish Kumar Singh; Saurav Das; Santosh Kumar; Varsha Rani Gajamer; Ishfaq Nabi Najar; Yangchen D. Lepcha; Hare Krishna Tiwari; Samer Singh
Every year millions of people die due to fatal waterborne diseases around the world especially in developing countries like India. Sikkim, a northeastern state of India, greatly depends on natural water sources. About 80% of the population of Sikkim depends on natural spring water for domestic as well as agricultural use. Recent waterborne disease outbreaks in the state raises a concerning question on water quality. In this study, we analyzed water quality especially for the detection of Enterobacteriaceae members from four districts of the state. Isolation with selective culture media techniques and taxonomic characterization of Enterobacteriaceae bacteria with 16S rRNA gene showed the prevalence of Escherichia coli (37.50%), Escherichia fergusonii (29.41%), Klebsiella oxytoca (36.93%), Citrobacter freundii (37.92%), Citrobacter amalonaticus (43.82%), Enterobacter sp. (43.82%), Morganella morganii (43.82%), Hafnia alvei (32.42%), Hafnia paralvei (38.74%), and Shigella flexneri (30.47%) in the spring water of Sikkim. Antibiotic susceptibility test (AST) showed resistance of the isolates to common antibiotics like ampicillin, amoxicillin as well as to third generation antibiotics like ceftazidime and carbapenem. None of the isolates showed resistance to chloramphenicol. E. coli isolated from spring water of Sikkim showed presence of different virulence genes such as stx1 (81.81%), elt (86.66%), and eae (66.66%) along with resistance gene for ampicillin (CITM) (80%), quinolones (qnrB) (44.44%), tetracycline (tetO) (66.66%), and streptomycin (aadA1) (66.66%). The data indicates a high incidence rate of multiple antibiotic resistant enteric bacteria in the spring water of Sikkim. Additionally, the presence of enteric bacteria in the water samples indicates widespread fecal contamination of the spring water. © Copyright © 2020 Singh, Das, Kumar, Gajamer, Najar, Lepcha, Tiwari and Singh.
Editorial: Understanding the impact of microbes on tumor progression and prevention: unveiling new avenues for cancer therapy
(Frontiers Media SA, 2025) Vikas Kumar Somani; Somya Aggarwal; Rajni Garg; Yoshiko Takeuchi; Samer Singh
[No abstract available]
Epidemiology of Human and Animal Anthrax in India, 1990–2022: A Comprehensive Analysis of Literature and National Surveillance Data
(John Wiley and Sons Ltd, 2025) Suresh Kuralayanapalya Puttahonnappa; Jessica A. Radzio-Basu; Hindol Maity; Ramya K. Rao; Robab Katani; Divakar Hemadri; Sharanagouda N. Patil; Jayashree Anand; Samer Singh; Divya Kandari; Rajinder Kaur; Rani Prameela; Shivaraj Murag; Niranjana R. Sahoo; Vivek Kapur; Shah S. Hossain; Mohan Kumar Papanna
Background: Anthrax, a neglected zoonotic disease caused by Bacillus anthracis, exerts considerable health consequences in resource-limited regions and is notably prevalent in India, causing persistent outbreaks that pose major animal and public health challenges. This study reviews the spatiotemporal patterns of human and animal anthrax outbreaks in India to identify high-risk areas and assess the correlation with environmental factors. Methods: A comprehensive literature search covering the period from 1990 to 2022 was conducted across various databases including CAB Direct, PubMed, Scopus, and Web of Science, alongside Indian government databases like the Integrated Disease Surveillance Programme (IDSP) and the National Animal Disease Referral Expert System (NADRES). We extracted data from studies published in English, using predefined keywords, and evaluated them using the Joanna Briggs Institute checklists. Data analysis was carried out using Microsoft Excel and EpiInfo, with spatial mapping in ArcGIS Pro. Results: Out of the 423 studies reviewed, 44 fulfilled our inclusion criteria, providing data on 174 human outbreaks (1778 cases, 130 fatalities) and 1775 animal outbreaks (7818 deaths). We identified key hotspots for human anthrax in West Bengal, Odisha, and Andhra Pradesh, and significant hotspots for animal anthrax in Karnataka, Andhra Pradesh, Tamil Nadu, and West Bengal. Majority of human outbreaks were reported between March and June, whereas the majority of animal outbreaks were reported between June and September. A strong correlation was observed between rainfall and animal outbreaks in the eastern region (correlation coefficient of 0.94). Conclusion: The study highlights key hotspots for human and animal anthrax and discrepancies in human and animal anthrax reporting and gaps in surveillance. There is a critical need for enhanced One Health surveillance and animal anthrax vaccination programs for effective management and mitigate the disease. These strategies are essential not only for public health and livestock welfare in India but also for global health security. © © 2025 Suresh K. Puttahonnappa et al. BioMed Research International published by John Wiley & Sons Ltd.
Higher BCG-induced trained immunity prevalence predicts protection from COVID-19: Implications for ongoing BCG trials
(Blackwell Publishing, 2022) Samer Singh; Dhiraj Kishore; Rakesh K. Singh; Chandramani Pathak; Kishu Ranjan
Endeavors to identify potentially protective variables for COVID-19 impact on certain populations have remained a priority. Multiple attempts have been made to attribute the reduced COVID-19 impact on populations to their Bacillus–Calmette–Guérin (BCG) vaccination coverage ignoring the fact that the effect of childhood BCG vaccination wanes within 5 years while most of the COVID-19 cases and deaths have occurred in aged with comorbidities. Since the supposed protection being investigated could come from heterologous ‘trained immunity’ (TI) conferred by exposure to Mycobacterium spp. (i.e., environmental and BCG), it is argued that the estimates of the prevalence of TI in populations currently available as latent tuberculosis infection (LTBI) prevalence would be a better variable to evaluate such assertions. Indeed, when we analyze the European populations (24), and erstwhile East and West Germany populations completely disregarding their BCG vaccination coverage, the populations with higher TI prevalence consistently display reduced COVID-19 impact as compared to their lower TI prevalence neighbors. The TI estimates of the populations not the BCG coverage per se, negatively correlated with pandemic phase-matched COVID-19 incidences (r(24): −0.79 to −0.57; p-value <.004), mortality (r(24): −0.63 to −0.45; p-value <.03), and interim case fatality rates (i-CFR) data. To decisively arrive at dependable conclusions about the potential protective benefit gained from BCG vaccination in COVID-19, the ongoing or planned randomized controlled trials should consciously consider including measures of TI as: (a) all individuals immunized do not respond equally, (b) small study groups from higher background TI could fail to indicate any protective effect. © 2022 The Authors. Clinical and Translational Discovery published by John Wiley & Sons Australia, Ltd on behalf of Shanghai Institute of Clinical Bioinformatics.
Leishmania antigens activated CD4+ T cells expressing CD200R receptors are the prime IL-10 producing phenotype and an important determinant of visceral leishmaniasis pathogenesis
(Academic Press, 2024) Abhishek Singh; Baishakhi Mahapatra; Arpita Banerjee; Samer Singh; Sangram Singh; Vikash K. Dubey; Pradeep Das; Rakesh K. Singh
The excessive production of IL-10, an anti-inflammatory cytokine, by Leishmania antigen-activated T cells is supposed to be a key player in the onset and progression of visceral leishmaniasis (VL). The IL-10-producing sources in VL remain unidentified and uncharacterized. In this study, we reveal that antigen-activated CD4+ T cells, i.e., CD44+CD4+ T cells expressing CD200R receptors, are the prime IL-10-producing phenotypes in Leishmania donovani infection-induced pathogenesis. These phenotypes are separate from CD25+Foxp3+CD4+ T regulatory cells, which are classical IL-10-producing phenotypes. In order to ascertain the role of CD200R and CD25 receptors in IL-10 overexpression-associated VL pathogenesis, we abrogated CD200R and CD25 receptor-mediated signaling in the infected mice. The splenic load of parasites and the size of the liver and spleen were significantly reduced in CD200-blocked mice as compared to CD25-blocked mice. Further, the CD200 blocking polarized CD4+ T cells to pro-inflammatory cytokines-producing phenotypes, as we observed a higher frequency of IFN-γ, TNF-α, and IL-12 positive cells as compared to controls including the CD25 blocking. Our findings suggest that in L. donovani infection-induced pathogenesis the expression of CD200R on antigen-activated T cells helps them to acquire IL-10-producing abilities as part of its one of the survival strategies. However, more studies would be warranted to better understand CD200R receptors role in VL pathogenesis and to develop the next generation of therapeutic and prophylactic control measures. © 2023 Elsevier Ltd
Leishmania donovani induces CD300a expression to dampen effector properties of CD11c+ dendritic and antigen activated CD8+ T cells
(Elsevier B.V., 2023) Anshul Anand; Rajan Singh; Shashi Saini; Baishakhi Mahapatra; Abhishek Singh; Samer Singh; Rakesh K. Singh
CD8+ T cells are an important regiment of adaptive immunity that play a decisive role in elimination of many species of Leishmania parasite from the host. In visceral leishmaniasis, caused by L. donovani, the loss of CD8+ T cells function has been found associated with augmented pathogenesis. The factors determining CD8+ T cells activation and function against Leishmania antigens are largely unknown. In this study, we investigated the role of an immune inhibitory receptor, CD300a, on the effector properties of dendritic cells and CD8+ T cells. We observed that the Leishmania regulates the effectors function of CD8+ T cells by increasing CD300a expression on CD11c+ dendritic cells. The abrogation of CD300a signaling in parasites infected animals induced CD8+ T cell abilities to produce IFN-γ, TNF-α and also helped them to acquire desired multifunctionality. The CD300a receptor blocking also enhanced the number of CD8+ T cells memory phenotypes at the early days of infection, suggesting its potential beneficial role in vaccine induced immunity. We also observed significantly enhanced levels of pro-inflammatory cytokines in the spleen of CD300a blocked infected animals with concomitant reduced spleen parasite load. Additionally, the abrogation of CD300a signals in the infected animals helped in establishing Th1 type protective humoral immunity with significantly elevated levels of IgG2a antibodies. Since CD8+ T cells are an important determinant of vaccine induced immunity against leishmaniasis, the findings corroborate the potential of CD300a in vaccine induced immunity and thus require further attention. © 2023 Elsevier B.V.
Modern Tools of Genome Engineering and Their Applications
(Springer Nature, 2023) Rajinder Kaur; Ashish Kumar Singh; Dinesh Kumar Singh; Samer Singh
Genome editing systems have emerged as an advanced bioengineering tool capable of targeting and editing the genomes of almost all organisms in a sequence-specific manner. This chapter presents an overview of the leading developments in the modern tool armory for genome editing that meet the high standards of efficiency, safety, and accessibility in genome engineering, i.e., ZFNs, TALENs, and CRISPR. These novel tools, primarily based on engineered nucleases, have proved to be one of the most effective and reliable tools for genome engineering. The engineered nucleases have enabled the alteration of targeted DNA sequences in a wide range of organisms and cell types. We will cover the mechanism and application of these methods for genome editing in current biology, functional genome screening, healthcare, agriculture, gene therapy, biological sciences, drug development, etc. General strategies used for designing specific ZFNs, TALENs, and CRISPR/Cas9 systems and analyzing their activity have been indicated. The therapeutic applications of these tools in controlling disease and their potential usage in the development of agricultural and industrial products, environmental protection, food development, immunotherapy, and treatment of genetic diseases, neurodegenerative diseases, and cancer are also briefly touched upon. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.