{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T21:40:05Z","timestamp":1790890805512,"version":"4.1.0"},"reference-count":37,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,2,9]],"date-time":"2026-02-09T00:00:00Z","timestamp":1770595200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001411","name":"Indian Council of Medical Research","doi-asserted-by":"publisher","award":["Project ID:  HIV\/50\/207\/09\/2020 ECD-11\/ICMR"],"award-info":[{"award-number":["Project ID:  HIV\/50\/207\/09\/2020 ECD-11\/ICMR"]}],"id":[{"id":"10.13039\/501100001411","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cell. Infect. Microbiol."],"abstract":"<jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>Effective HBV therapy and immunisation require knowledge of HBV mutation rate and genetic variability. This study aimed to characterize HBV genotypes, serotypes, and surface (S) gene mutations among HBV\u2013HIV co-infected and HBV mono-infected patients in North India.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>A total of 100 HBV\u2013HIV co-infected and 50 HBV mono-infected patients were enrolled. HBV DNA was extracted from serum using the QIAamp DNA Blood Mini Kit (QIAGEN). HBV viral load was quantified by real-time PCR. The HBV surface gene was amplified using conventional and nested PCR, followed by Sanger sequencing for genotyping, serotyping, and mutational analysis. Genotypes were additionally confirmed using type-specific multiplex PCR.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The mean age of HIV-HBV co-infected and HBV mono-infected patients was 36.6 and 34.9 years, respectively. HBeAg positivity was observed in 17% of co-infected and 10% of HBV mono-infected cases. HBV surface gene was successfully amplified in 19 (19%) HIV-HBV co-infected and 20 (40%) HBV mono-infected samples. Genotype D predominated (35\/39, 89.7%), with subgenotypes D1 and D3 detected at comparable frequencies, while genotype A was identified in 4 (10.3%) samples, all belonging to subgenotype A1. Serotype analysis showed exclusive association of genotype D with ayw2 and genotype A with adw2. Mutations within the HBsAg \u2018a\u2019 determinant region were identified in 36.8% of HBV\u2013HIV co-infected patients, including nonsynonymous substitutions, whereas no such mutations were observed in HBV mono-infected individuals. Genotype D sequences clustered with subgenotypes D2, D3, and D9 (from West Bengal), as well as D3 (from Russia, Madhya Pradesh, Delhi and Brazil).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>This study confirms the predominance of HBV genotype D with serotype ayw2 in North India and demonstrates a higher frequency of HBsAg immune escape\u2013associated mutations in HBV\u2013HIV co-infected patients. These findings underscore the importance of ongoing molecular surveillance to inform diagnostic strategies, vaccination effectiveness, and clinical management of HBV, particularly in HIV-affected populations.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fcimb.2025.1731472","type":"journal-article","created":{"date-parts":[[2026,2,9]],"date-time":"2026-02-09T07:29:22Z","timestamp":1770622162000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":3,"title":["HBV genotype distribution and S gene mutations in HIV-HBV co-infected patients: insights from North India"],"prefix":"10.3389","volume":"15","author":[{"given":"Hiba","family":"Sami","sequence":"first","affiliation":[{"name":"Department of Microbiology, Jawaharlal Nehru Medical College, Aligarh Muslim University","place":["Aligarh, India"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohd","family":"Asaad","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Jawaharlal Nehru Medical College, Aligarh Muslim University","place":["Aligarh, India"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Syed Haider Mehdi","family":"Husaini","sequence":"additional","affiliation":[{"name":"Department of Medicine, Jawaharlal Nehru Medical College, Aligarh Muslim University","place":["Aligarh, India"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Parvez Anwar","family":"Khan","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Jawaharlal Nehru Medical College, Aligarh Muslim University","place":["Aligarh, India"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adil","family":"Raza","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Jawaharlal Nehru Medical College, Aligarh Muslim University","place":["Aligarh, India"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nazish","family":"Fatima","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Jawaharlal Nehru Medical College, Aligarh Muslim University","place":["Aligarh, India"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haris M.","family":"Khan","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Jawaharlal Nehru Medical College, Aligarh Muslim University","place":["Aligarh, India"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,2,9]]},"reference":[{"key":"B1","volume-title":"HIV Facts & Figures","year":"2019"},{"key":"B2","doi-asserted-by":"publisher","first-page":"5964","DOI":"10.3748\/wjg.v12.i37.5964","article-title":"Distribution of hepatitis B virus genotypes: phylogenetic analysis and virological characteristics of genotype C circulating among HBV carriers in Kolkata, Eastern India","volume":"12","author":"Banerjee","year":"2006","journal-title":"World J. 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