{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T08:57:09Z","timestamp":1790240229758,"version":"4.1.0"},"reference-count":36,"publisher":"American Society for Microbiology","issue":"1","license":[{"start":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T00:00:00Z","timestamp":1767657600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/100017540","name":"Division of Intramural Research","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100017540","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100031251","name":"College of Medicine, University of Arkansas for Medical Sciences","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100031251","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Microbiol Spectr"],"published-print":{"date-parts":[[2026,1,6]]},"abstract":"ABSTRACT<\/jats:title>\n \n \n \n Coxiella burnetii<\/jats:italic>\n is an intracellular bacterial pathogen that causes the disease Q fever. Both secretion of effector proteins by a type IVB secretion system and expression of lipopolysaccharide (LPS) are critical for\n C. burnetii<\/jats:italic>\n virulence. The\n C. burnetii<\/jats:italic>\n Nine Mile strain lineage is routinely used in laboratories, with Nine Mile I RSA493 (fully virulent) expressing phase I LPS, Nine Mile Crazy RSA514 (lightly attenuated) expressing intermediate LPS, and NMII RSA439 clone 4 (NMII, attenuated) expressing phase II LPS. NMII was exempted from the U.S. Centers for Disease Control and Prevention Federal Select Agent Program due to a genetic deletion predicted to prevent phase I LPS synthesis; however, recent findings demonstrated that NMII LPS elongation occurs\n in vivo<\/jats:italic>\n and\n in vitro<\/jats:italic>\n . These findings raise concerns regarding the suitability of NMII for manipulation at biosafety level-2 (BSL-2) containment. Here, we evaluated a mutant strain lacking the gene responsible for LPS elongation (\n C. burnetii<\/jats:italic>\n NMII \u0394\n cbu0533<\/jats:italic>\n ) as an alternative strain for BSL-2 containment studies. Growth of wild-type NMII and NMII \u0394\n cbu0533<\/jats:italic>\n in axenic media and macrophages was evaluated. Neither growth kinetics nor replication vacuole morphology significantly differed between strains. NMII \u0394\n cbu0533<\/jats:italic>\n also prevented staurosporine-induced cell death, indicating that the mutant strain maintains the capacity to alter cell signaling events similar to wild-type\n C. burnetii<\/jats:italic>\n . Cumulatively, these data reveal that\n C. burnetii<\/jats:italic>\n NMII \u0394\n cbu0533<\/jats:italic>\n is a suitable alternative to wild-type NMII in BSL-2 laboratory experiments that can be distributed to the field for use.\n <\/jats:p>\n \n IMPORTANCE<\/jats:title>\n \n Attenuated\n C. burnetii<\/jats:italic>\n NMII RSA439 clone 4 (NMII) expresses truncated lipopolysaccharide (LPS) and was long predicted to be unable to produce elongated LPS due to a large chromosomal deletion. As a result, this strain was exempted from the CDC Federal Select Agent Program\u2019s regulation and is commonly used under biosafety level-2 laboratory conditions. Recently, it was shown that\n C. burnetii<\/jats:italic>\n NMII LPS can elongate due to a mutation reversion in\n cbu0533<\/jats:italic>\n , resulting in increased virulence in guinea pigs. As a result, the previously exempted NMII strain is subject to regulation if the\n cbu0533<\/jats:italic>\n mutation reversion is present, posing concerns regarding laboratory use. Experiments described here provide a suitable alternative strain to address these concerns.\n <\/jats:p>\n <\/jats:sec>\n <\/jats:sec>","DOI":"10.1128\/spectrum.01961-25","type":"journal-article","created":{"date-parts":[[2025,12,4]],"date-time":"2025-12-04T14:00:26Z","timestamp":1764856826000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":2,"title":["Coxiella burnetii<\/i>\n Nine Mile II \u0394\n cbu0533<\/i>\n as a suitable laboratory replacement strain"],"prefix":"10.1128","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-2448-1822","authenticated-orcid":true,"given":"Kathleen N.","family":"Pierce","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}],"name":"Laboratory of Bacteriology, Division of Intramural Research, National Institutes of Health, National Institute of Allergy and Infectious Disease","place":["Hamilton, USA"]},{"id":[{"id":"https:\/\/ror.org\/00xcryt71","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Microbiology and Immunology, University of Arkansas for Medical Sciences","place":["Little Rock, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Catharine S.","family":"Frederick","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}],"name":"Laboratory of Bacteriology, Division of Intramural Research, National Institutes of Health, National Institute of Allergy and Infectious Disease","place":["Hamilton, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Connor","family":"Farquhar","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}],"name":"Laboratory of Bacteriology, Division of Intramural Research, National Institutes of Health, National Institute of Allergy and Infectious Disease","place":["Hamilton, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7631-7827","authenticated-orcid":true,"given":"Daniel E.","family":"Voth","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00xcryt71","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Microbiology and Immunology, University of Arkansas for Medical Sciences","place":["Little Rock, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5030-975X","authenticated-orcid":true,"given":"Carrie Mae","family":"Long","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}],"name":"Laboratory of Bacteriology, Division of Intramural Research, National Institutes of Health, National Institute of Allergy and Infectious Disease","place":["Hamilton, USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_3_2_2","doi-asserted-by":"publisher","DOI":"10.1051\/vetres:2005010"},{"key":"e_1_3_3_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/0002-9343(66)90085-4"},{"key":"e_1_3_3_4_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1462-5822.2007.00901.x"},{"key":"e_1_3_3_5_2","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.00406-10"},{"key":"e_1_3_3_6_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41541-021-00296-6"},{"key":"e_1_3_3_7_2","doi-asserted-by":"publisher","DOI":"10.1128\/spectrum.00696-23"},{"key":"e_1_3_3_8_2","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.01124-08"},{"key":"e_1_3_3_9_2","doi-asserted-by":"publisher","DOI":"10.1128\/JB.00071-13"},{"key":"e_1_3_3_10_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0501863102"},{"key":"e_1_3_3_11_2","doi-asserted-by":"publisher","DOI":"10.1128\/iai.56.4.802-807.1988"},{"key":"e_1_3_3_12_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1749-6632.1990.tb42203.x"},{"key":"e_1_3_3_13_2","doi-asserted-by":"publisher","DOI":"10.1139\/m57-046"},{"key":"e_1_3_3_14_2","doi-asserted-by":"publisher","DOI":"10.1139\/m56-036"},{"key":"e_1_3_3_15_2","doi-asserted-by":"publisher","DOI":"10.1128\/iai.38.1.53-57.1982"},{"key":"e_1_3_3_16_2","doi-asserted-by":"publisher","DOI":"10.1128\/jb.160.3.994-1002.1984"},{"key":"e_1_3_3_17_2","doi-asserted-by":"publisher","DOI":"10.1128\/iai.55.5.1144-1150.1987"},{"key":"e_1_3_3_18_2","unstructured":"History. 2020. Federal select agent program. Available from: https:\/\/www.selectagents.gov\/overview\/history.htm. Retrieved 15 Apr 2021."},{"key":"e_1_3_3_19_2","doi-asserted-by":"publisher","DOI":"10.1128\/iai.48.2.359-365.1985"},{"key":"e_1_3_3_20_2","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.70.12.6726-2733.2002"},{"key":"e_1_3_3_21_2","doi-asserted-by":"publisher","DOI":"10.1016\/0966-842x(96)81555-1"},{"key":"e_1_3_3_22_2","doi-asserted-by":"publisher","DOI":"10.1099\/00221287-132-9-2587"},{"key":"e_1_3_3_23_2","unstructured":"2003. Select agents and toxins exclusions: excluded attenuated strains of HHS select agents section 73.3 (e) Coxiella burneti. Division of Regulatory Science and Compliance Centers for Disease Control. Available from: https:\/\/selectagents.gov\/sat\/exclusions\/hhs.htm"},{"key":"e_1_3_3_24_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-023-43972-y"},{"key":"e_1_3_3_25_2","doi-asserted-by":"publisher","DOI":"10.1371\/journal.ppat.1006922"},{"key":"e_1_3_3_26_2","unstructured":"Select agent determination concerning Coxiella burnetii phase II Nine Mile strain plaque purified clone 4 with reversion to wildtype cbu0533 54247. 2023. Caners for Disease Control (CDC) DoHaHSH Federal Register: United States Government"},{"key":"e_1_3_3_27_2","doi-asserted-by":"publisher","DOI":"10.1128\/mra.00730-24"},{"key":"e_1_3_3_28_2","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0812074106"},{"key":"e_1_3_3_29_2","doi-asserted-by":"publisher","DOI":"10.1080\/21505594.2019.1575715"},{"key":"e_1_3_3_30_2","doi-asserted-by":"publisher","DOI":"10.1007\/BF02041244"},{"key":"e_1_3_3_31_2","doi-asserted-by":"publisher","DOI":"10.1111\/cmi.12096"},{"key":"e_1_3_3_32_2","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.00012-16"},{"key":"e_1_3_3_33_2","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.169.8.4488"},{"key":"e_1_3_3_34_2","doi-asserted-by":"publisher","DOI":"10.1128\/iai.40.3.1155-1162.1983"},{"key":"e_1_3_3_35_2","doi-asserted-by":"publisher","DOI":"10.1016\/0014-5793(95)01116-v"},{"key":"e_1_3_3_36_2","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.00594-07"},{"key":"e_1_3_3_37_2","unstructured":"United States Centers for Disease Control. 2024. Clinical and laboratory diagnosis for Q fever. United States Centers for Disease Control. Available from: https:\/\/www.cdc.gov\/q-fever\/hcp\/diagnosis-testing\/index.html"}],"container-title":["Microbiology Spectrum"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/spectrum.01961-25","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.asm.org\/doi\/pdf\/10.1128\/spectrum.01961-25","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T14:07:58Z","timestamp":1767708478000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.asm.org\/doi\/10.1128\/spectrum.01961-25"}},"subtitle":[],"editor":[{"given":"Kathryn T.","family":"Elliott","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,1,6]]},"references-count":36,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2026,1,6]]}},"alternative-id":["10.1128\/spectrum.01961-25"],"URL":"https:\/\/doi.org\/10.1128\/spectrum.01961-25","relation":{},"ISSN":["2165-0497"],"issn-type":[{"value":"2165-0497","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,6]]},"assertion":[{"value":"2025-06-26","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-10-30","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-12-04","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e01961-25"}}