{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T13:37:32Z","timestamp":1785418652108,"version":"3.56.0"},"reference-count":17,"publisher":"American Society for Microbiology","issue":"4","license":[{"start":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T00:00:00Z","timestamp":1783382400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,7,7]],"date-time":"2026-07-07T00:00:00Z","timestamp":1783382400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/100009619","name":"Japan Agency for Medical Research and Development","doi-asserted-by":"publisher","award":["JP25fk0108722"],"award-info":[{"award-number":["JP25fk0108722"]}],"id":[{"id":"10.13039\/100009619","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["ASM Case Rep"],"published-print":{"date-parts":[[2026,7,7]]},"abstract":"ABSTRACT<\/jats:title>\n \n \n \n Background<\/jats:title>\n \n Bordetella pertussis<\/jats:italic>\n infection causes severe respiratory illness, particularly in young infants. Although macrolides are recommended as the first-line treatment, macrolide-resistant strains have emerged in several countries. In Japan, a nationwide pertussis epidemic occurred in 2025, during which numerous infections were reported not only due to macrolide-susceptible\n B. pertussis<\/jats:italic>\n (MSBP) but also due to macrolide-resistant strains (MRBP).\n <\/jats:p>\n <\/jats:sec>\n \n Case Summary<\/jats:title>\n \n A 2-month-old female developed a persistent cough and was admitted to the pediatric intensive care unit (PICU), where she received frequent suctioning and short-term high-flow nasal cannula therapy. BioFire FilmArray Respiratory Panel 2.1 analysis of her nasal swab detected\n B. pertussis<\/jats:italic>\n DNA; azithromycin was therefore administered for 5 days. Direct sequencing of the DNA extracted from her nasal swabs initially indicated an A2047G mutation in the 23S rRNA gene of\n B. pertussis,<\/jats:italic>\n indicating MRBP infection, although the electropherogram was unclear. Trimethoprim-sulfamethoxazole was initiated on day 8 of her PICU stay following confirmation of MRBP infection. Subsequently, bacterial culture yielded two different\n B. pertussis<\/jats:italic>\n strains, which were confirmed as MRBP and MSBP through antimicrobial susceptibility testing. Multilocus variable-number tandem-repeat analysis and whole-genome analysis demonstrated that the strains were genetically unrelated. The patient was discharged and subsequently fully recovered after a 14 day course of trimethoprim-sulfamethoxazole.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n To our knowledge, this is the first confirmed case of co-infection with MRBP and MSBP strains. Such mixed infections may be missed by the diagnostic methods currently used in clinical practice, highlighting the importance of careful interpretation of test results.<\/jats:p>\n <\/jats:sec>\n <\/jats:sec>","DOI":"10.1128\/asmcr.00242-25","type":"journal-article","created":{"date-parts":[[2026,4,24]],"date-time":"2026-04-24T13:00:32Z","timestamp":1777035632000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Co-infection with macrolide-resistant and macrolide-susceptible\n Bordetella pertussis<\/i>\n strains in an infant: a case report"],"prefix":"10.1128","volume":"2","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9840-3689","authenticated-orcid":true,"given":"Kentaro","family":"Koide","sequence":"first","affiliation":[{"name":"Department of Bacteriology II, National Institute of Infectious Diseases, Japan Institute for Health Security","place":["Musashimurayama, 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