{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T13:40:15Z","timestamp":1781876415625,"version":"3.54.5"},"reference-count":45,"publisher":"Public Library of Science (PLoS)","issue":"1","license":[{"start":{"date-parts":[[2023,1,23]],"date-time":"2023-01-23T00:00:00Z","timestamp":1674432000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004484","name":"Tehran University of Medical Sciences and Health Services","doi-asserted-by":"publisher","award":["40984"],"award-info":[{"award-number":["40984"]}],"id":[{"id":"10.13039\/501100004484","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>Since the introduction of the Bacillus Calmette\u2013Gu\u00e9rin (BCG) vaccine, the genomes of vaccine strains have undergone variations due to repeated passages in different laboratories and vaccine production facilities. Genetic variations have been considered as one of the effective factors in the BCG variable protective efficacy. Consecutive subcultures have been shown to play an essential role in causing genetic variations in several microorganisms, including <jats:italic>Mycobacterium bovis<\/jats:italic> BCG. Therefore, the world health organization (WHO) recommendation to limit the passages of master seed lot in the BCG vaccine production should be considered. Besides, the role of other external variables such as quality of the raw ingredients of the culture media, the type of the culture medium and the cultivation methods in the vaccine production has been poorly studied. Here, the effect of passages and culture medium on genetic variations in a BCG seed lot was investigated during a year. The findings of this study revealed a total of 19 variants compared to seed lot while the passages were more than the number recommended by WHO. The first culture of seed lot in the Sauton broth and Middlebrook 7H9 media, and the last subculture in Sauton broth had the least and the most variants, respectively. The observation of the higher number of variants in the last cultures on Sauton broth and Middlebrook 7H9 in comparison to the first and the middle cultures may indicate the effect of passages on the genetic variations in BCG. Additionally, more variants in BCG grown in the Sauton broth do not necessarily represent the greater ability of this medium to cause genetic mutations. For a better conclusion, it is required to examine the medium components as independent variables.<\/jats:p>","DOI":"10.1371\/journal.pone.0280294","type":"journal-article","created":{"date-parts":[[2023,1,23]],"date-time":"2023-01-23T18:29:52Z","timestamp":1674498592000},"page":"e0280294","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":2,"title":["The effect of in vitro consecutive passages and culture medium on the genetic variations in BCG Pasteur 1173P2 vaccine"],"prefix":"10.1371","volume":"18","author":[{"given":"Mahla","family":"Asadian","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seyed Mehdi","family":"Hassanzadeh","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Azadeh","family":"Safarchi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5861-3182","authenticated-orcid":true,"given":"Masoumeh","family":"Douraghi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2023,1,23]]},"reference":[{"key":"pone.0280294.ref001","doi-asserted-by":"crossref","first-page":"155","DOI":"10.1007\/978-3-319-64371-7_8","article-title":"Evolution and Strain Variation in BCG","volume":"1019","author":"AM Abdallah","year":"2017","journal-title":"Adv Exp Med Biol"},{"issue":"1","key":"pone.0280294.ref002","doi-asserted-by":"crossref","first-page":"MGM2-0028-2013","DOI":"10.1128\/microbiolspec.MGM2-0028-2013","article-title":"BCG vaccines","volume":"2","author":"V Tran","year":"2014","journal-title":"Microbiol Spectr"},{"issue":"9","key":"pone.0280294.ref003","doi-asserted-by":"crossref","first-page":"698","DOI":"10.1001\/jama.1994.03510330076038","article-title":"Efficacy of BCG vaccine in the prevention of tuberculosis: meta-analysis of the published literature","volume":"271","author":"GA Colditz","year":"1994","journal-title":"JAMA"},{"issue":"Supplement_3","key":"pone.0280294.ref004","doi-asserted-by":"crossref","first-page":"S64","DOI":"10.1086\/314072","article-title":"Preventing tuberculosis with bacillus Calmette-Guerin vaccine: a meta-analysis of the literature","volume":"31","author":"TF Brewer","year":"2000","journal-title":"Clin Infect Dis"},{"issue":"2","key":"pone.0280294.ref005","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1016\/S1473-3099(02)00182-2","article-title":"BCG\u2014different strains, different vaccines?","volume":"2","author":"MA Behr","year":"2002","journal-title":"Lancet Infect Dis"},{"issue":"4","key":"pone.0280294.ref006","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1016\/0197-2456(94)90042-6","article-title":"Field trials of tuberculosis vaccines: how could we have done them better?.","volume":"15","author":"GW Comstock","year":"1994","journal-title":"Control Clin Trials"},{"issue":"2","key":"pone.0280294.ref007","doi-asserted-by":"crossref","first-page":"70","DOI":"10.4161\/hv.5.2.7210","article-title":"BCG vaccines: their mechanisms of attenuation and impact on safety and protective efficacy","volume":"5","author":"J Liu","year":"2009","journal-title":"Hum Vaccin"},{"issue":"6","key":"pone.0280294.ref008","doi-asserted-by":"crossref","first-page":"1038","DOI":"10.1016\/j.vaccine.2011.12.044","article-title":"In vitro culture medium influences the vaccine efficacy of Mycobacterium bovis BCG","volume":"30","author":"MM Venkataswamy","year":"2012","journal-title":"Vaccine"},{"issue":"17","key":"pone.0280294.ref009","doi-asserted-by":"crossref","first-page":"2056","DOI":"10.1016\/j.vaccine.2015.02.056","article-title":"Variation of growth in the production of the BCG vaccine and the association with the immune response. 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