Biomedical subjects

Arnab Sen

Publications and source records attributed to Arnab Sen.

3 recordsLinked to original sources

PubMed2026

Genomic diversity and resistance determinants of staphylococci from cow and buffalo milk.

BACKGROUND: Staphylococci are important mastitis pathogens in dairy animals and serve as reservoirs of antimicrobial resistance genes (ARGs) having zoonotic potential. Genomic characterization of resistant isolates is essential to understand their diversity, resistance mechanisms, and One Health implications. METHODS AND RESULTS: A total of 363 cow and buffalo milk samples-including 108 from animals with mastitis-were screened, yielding 98 staphylococcal isolates, comprising 20 Staphylococcus aureus and 78 coagulase-negative staphylococci (CoNS). Antimicrobial susceptibility testing revealed resistance to cefoxitin (CoNS: 21.7%; S. aureus: 10%), tetracycline (CoNS: 19.2%; S. aureus: 10%), erythromycin (CoNS:16.7%; S. aureus: 10%), gentamicin (CoNS: 10.2%; S. aureus: 10%) and fluoroquinolone (CoNS: 10.2%), while the majority were sensitive to chloramphenicol, cotrimoxazole (~ 95%, each), linezolid (~ 97%), and vancomycin (100%). Nineteen isolates, including two S. aureus, were cefoxitin-resistant, and eight carried the mecA gene. Whole genome sequencing of these eight isolates revealed genome sizes ranging from 2.27 to 2.78 MB, with the methicillin resistant S. aureus (MRSA, ERSST98) isolate possessing the largest genome and the highest rRNA copy number. Comparative genomic analysis revealed various SCCmec types along with an extensive array of resistance determinants, encompassing aminoglycosides, macrolides, tetracyclines, efflux systems, and heavy metals, underscoring the multifaceted resistance repertoire of these strains. Virulence profiling of ERSST98 demonstrated a broad arsenal of adhesins, toxins, and biofilm‑associated genes, highlighting its pathogenic capacity. Mobile genetic elements with diverse plasmid replicons and insertion sequence families further contributed to genomic plasticity. CONCLUSIONS: Collectively, this study underscores the genomic diversity of methicillin-resistant staphylococci from dairy animals with extensive resistance determinants and highlights their zoonotic relevance within One Health framework.

Animals↗

PubMed2025

Phytocompounds of Honey mesquite (Prosopis glandulosa) and Lodhra (Symplocos racemosa) in the management of COVID-19 associated rheumatoid arthritis (CARA).

COVID-19 persists globally with profound social and economic consequences, and its complex interplay with other diseases makes it a syndemic. Rheumatoid arthritis (RA), a chronic autoimmune disorder, has shown increased incidence during the pandemic, with patients displaying higher susceptibility to COVID-19. This overlap prompted the hypothesis of 'COVID-19-associated rheumatoid arthritis (CARA)'. The present study explores phytocompounds with anti-inflammatory and immunomodulatory properties as potential CARA therapeutics. Compounds from Prosopis glandulosa and Symplocos racemosa, both used in traditional medicine, were evaluated through molecular docking and simulation studies. Six inflammatory targets relevant to RA and COVID-19 -interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), granulocyte-macrophage colony-stimulating factor (GM-CSF), human leukocyte antigen DR4 (HLA-DR4), signal transducer and activator of transcription 4 (STAT4), and peptidyl arginine deiminase 4 (PAD4) were selected. Among the tested ligands, salidroside showed the strongest binding affinity, with energies of - 8.20 kcal/mol (IL-6), - 7.67 kcal/mol (TNF-α), - 8.53 kcal/mol (GM-CSF), - 8.80 kcal/mol (HLA-DR4), - 8.18 kcal/mol (STAT4), and - 7.91 kcal/mol (PAD4), indicating stable interactions. These findings suggest salidroside could modulate key inflammatory pathways and potentially reduce cytokine storms in COVID-19 patients. Existing RA and COVID-19 treatments often cause immunosuppression, increasing vulnerability to opportunistic infections (Datta et al in J Biomol Struct Dyn 41(8):3281-3294, 2022). Immunomodulatory phytocompounds like salidroside may offer safer, targeted alternatives without compromising immune defenses. However, this study is based on in silico analyses, and warrants in vitro and in vivo validation. Nevertheless, present work may represent an important step towards novel therapeutic strategies for COVID-19 Associated Rheumatoid Arthritis (CARA).

COVID-19↗

PubMed2025

Development of a multiplex PCR for detection of pathogenic Mycobacterium orygis in cattle tissues harboring tuberculous-like lesions.

Mycobacterium orygis, a recently defined member species of Mycobacterium tubercuolsis complex (MTBC), is emerging as a major threat to zoonotic tuberculosis control, especially in the Asian Subcontinent. The dearth of low-cost diagnostic assay to differentiate M. orygis from other members of the MTBC leads to unavailability of information about the actual burden of this species in human and animal population. In this study, we developed a multiplex PCR for distinguishing M. orygis from other MTBC based on two M. orygis-specific nonsynonymous point mutations in mbtG and fadD23 genes identified by comparative genome analysis. The specificity of the assay shows that a 434 bp IS1081 fragment was amplified from common MTBC species including M. orygis while 240 bp and 181 bp mbtG and fadD23 gene fragments were amplified only from M. orygis. No amplification was observed for nontuberculous Mycobacterium (NTM) and non-Mycobacterial pathogens. The multiplex PCR assay showed a detection limit of 32 pg of M. orygis DNA. Furthermore, a total of 85 tuberculous-like lesions in the different tissues of slaughtered cattle were tested for identification of the M. orygis, and the results showed IS1081, mbtG and fadD23 amplicons in three tissue DNA extracts confirming they contain M. orygis DNA. Also, a single IS1081 amplicon was amplified from one tissue sample signifying presence of DNA of any MTBC species other than M. orygis. An established TaqMan real time PCR assay targeting region of differences (RD) in M. orygis genome was carried out to validate the result of the assay. This showed 100 % accuracy of the in-house developed multiplex PCR.

Mycobacterium orygis↗