{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T20:38:16Z","timestamp":1792787896133,"version":"4.5.0"},"reference-count":19,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T00:00:00Z","timestamp":1783382400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"vor","delay-in-days":85,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"name":"Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan","award":["AP23489672"],"award-info":[{"award-number":["AP23489672"]}],"id":[{"id":"https:\/\/ror.org\/05tyne317","id-type":"ROR","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["BMC Microbiol"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>\n                      Syphilis remains a major sexually transmitted infection worldwide.\n                      <jats:italic>Treponema pallidum<\/jats:italic>\n                      subspecies\n                      <jats:italic>pallidum<\/jats:italic>\n                      is difficult to investigate under conventional laboratory cultivation conditions, which limits experimental and molecular studies involving clinical material. This pilot exploratory study aimed to obtain preliminary molecular evidence of\n                      <jats:italic>Treponema pallidum<\/jats:italic>\n                      -related rabbit-derived material following inoculation with human chancre-derived clinical specimens. Chancre-derived clinical material was examined by dark-field microscopy and used for experimental intratesticular inoculation in rabbits, followed by real-time polymerase chain reaction (PCR), conventional PCR targeting partial 16\u00a0S ribosomal RNA gene fragments, Sanger sequencing, and phylogenetic analysis.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Thin spiral-shaped structures morphologically consistent with treponemal organisms were observed in selected clinical specimens by dark-field microscopy. Real-time PCR demonstrated amplification signals consistent with\n                      <jats:italic>Treponema pallidum<\/jats:italic>\n                      -related DNA in three rabbit-derived samples following initial inoculation. Because inflammatory findings remained limited, these PCR-positive rabbits subsequently received secondary intratesticular inoculation using cryopreserved chancre-derived material as an exploratory modification intended to improve recovery of rabbit-derived material for downstream molecular analysis. Following secondary inoculation, these PCR-positive rabbits developed unilateral orchitis-like inflammatory changes involving the secondarily inoculated (contralateral) testis. Conventional PCR generated partial 16\u00a0S rRNA gene amplicons of the expected size (~\u20091.5\u00a0kb) in PCR-positive samples. Sequencing analysis demonstrated high similarity to published\n                      <jats:italic>Treponema pallidum<\/jats:italic>\n                      reference sequences, with sequence identity ranging from approximately 99.45% to 100%. Phylogenetic analysis demonstrated clustering of the obtained sequences with published\n                      <jats:italic>Treponema pallidum<\/jats:italic>\n                      reference sequences retrieved from GenBank.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>\n                      The combined use of dark-field microscopy, experimental rabbit inoculation, species-specific real-time PCR, sequencing, and phylogenetic analysis enabled preliminary molecular detection and partial sequence-based characterization of rabbit-derived\n                      <jats:italic>Treponema pallidum<\/jats:italic>\n                      -related material obtained following inoculation with chancre-derived clinical specimens. Although exploratory and limited by the small number of positive samples and partial 16\u00a0S ribosomal RNA gene analysis, the findings provide preliminary molecular evidence supporting the potential usefulness of rabbit-based experimental approaches for downstream molecular investigations.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s12866-026-05386-w","type":"journal-article","created":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T10:53:49Z","timestamp":1783421629000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Molecular characterization of Treponema pallidum-related rabbit-derived material following experimental inoculation with human chancre-derived clinical specimens: a pilot exploratory study"],"prefix":"10.1186","volume":"26","author":[{"given":"Nazym","family":"Syrym","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Akbope","family":"Abdykalyk","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sabit","family":"Kokanov","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bolat","family":"Yespembetov","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aziz","family":"Nakhanov","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aibol","family":"Terebay","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alinur","family":"Toleukhan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sabira","family":"Alpysbayeva","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aktoty","family":"Anarbekova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Makhpal","family":"Sarmykova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yeldos","family":"Serikbay","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bekzat","family":"Yerzhigit","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kali","family":"Tileukhanov","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aigerim","family":"Zhakypbek","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Azamat","family":"Abdimukhtar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,7,7]]},"reference":[{"key":"5386_CR1","unstructured":"World Health Organization. Implementing the global health sector strategies on HIV, viral hepatitis and sexually transmitted infections, 2022\u20132030: report on progress and gaps 2024, second edition. https:\/\/www.who.int\/publications\/i\/item\/9789240097872. Accessed 10 May 2026."},{"key":"5386_CR2","doi-asserted-by":"publisher","first-page":"17073","DOI":"10.1038\/nrdp.2017.73","volume":"3","author":"RW Peeling","year":"2017","unstructured":"Peeling RW, Mabey D, Kamb ML, Chen XS, Radolf JD, Benzaken AS, Syphilis. Nat Rev Dis Primers. 2017;3:17073.","journal-title":"Nat Rev Dis Primers"},{"issue":"6","key":"5386_CR3","doi-asserted-by":"publisher","first-page":"827","DOI":"10.1089\/jwh.2024.0367","volume":"33","author":"K Hufstetler","year":"2024","unstructured":"Hufstetler K, Llata E, Miele K, Quilter LAS. Clinical updates in sexually transmitted infections, 2024. 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The study involving human participants was conducted in accordance with the Declaration of Helsinki. The collection and use of chancre-derived clinical specimens were approved by the Local Bioethics Committee of the Research Institute for Biological Safety Problems, Republic of Kazakhstan (Protocol No. 4, dated 19 November 2024). Written informed consent was obtained from all participants before sample collection. Animals. Animal experiments were approved by the Local Bioethics Committee of the Research Institute for Biological Safety Problems, Republic of Kazakhstan (Protocol No. 5, dated 21 November 2024). All animal procedures were conducted in accordance with institutional guidelines for the care and use of laboratory animals and applicable national regulations. The rabbits were obtained from the institutional animal facility of the Research Institute for Biological Safety Problems; therefore, owner consent was not applicable. Animal handling, inoculation procedures, euthanasia, and tissue collection were performed under veterinary supervision, with measures taken to minimize pain, discomfort, and stress. Humane endpoints were defined before the start of the study, and animals were monitored daily for general clinical condition, appetite, behaviour, and local inflammatory reactions at the inoculation site.","order":1,"name":"Ethics","label":"Ethics approval and consent to participate","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"Not applicable.","order":2,"name":"Ethics","label":"Consent for publication","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare no competing interests.","order":3,"name":"Ethics","label":"Competing interests","group":{"name":"EthicsHeading","label":"Declarations"}}],"article-number":"845"}}