{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,30]],"date-time":"2026-10-30T18:41:15Z","timestamp":1793385675332,"version":"4.5.0"},"reference-count":26,"publisher":"Oxford University Press (OUP)","issue":"2","license":[{"start":{"date-parts":[[2025,3,22]],"date-time":"2025-03-22T00:00:00Z","timestamp":1742601600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"name":"ITM's SOFI program"},{"name":"Flemish Government, Science & Innovation","award":["DIR\/av\/2020\/119"],"award-info":[{"award-number":["DIR\/av\/2020\/119"]}],"id":[{"id":"https:\/\/ror.org\/04qxsrb28","id-type":"ROR","asserted-by":"crossref"}]},{"name":"The Belgian Federal Public Service of Development Cooperation","award":["BE-BCE_KBO-0410057701-prg2022-13-RW"],"award-info":[{"award-number":["BE-BCE_KBO-0410057701-prg2022-13-RW"]}]},{"name":"Research Foundation\u2014Flanders","award":["1SE7622N"],"award-info":[{"award-number":["1SE7622N"]}]},{"name":"Belgian Directorate General for Development Cooperation"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,9,16]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Xpert MTB\/RIF Ultra (Ultra) aimed to improve the specificity in identifying rifampicin-resistant tuberculosis (RR-TB), compared to Xpert MTB\/RIF.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In a nationwide study in Rwanda, patients diagnosed with RR-TB by Ultra between December 2021 and January 2024 underwent repeat Ultra testing, complemented by rpoB gene sequencing and phenotypic drug-susceptibility testing (pDST), serving as reference tests.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Of 129 patients initially diagnosed with RR-TB by Ultra, only 41 (32%) had concordant rifampicin results upon repeat Ultra testing. The remaining 88 patients (68%) had unconfirmed resistance on repeat Ultra. Reference testing was available for 40 (98%) of 41 confirmed cases, all verified as true RR-TB. Among 88 unconfirmed cases, reference testing was available for 61 (69%), with 7 (11%) confirmed as true RR-TB, whereas 54 (89%) were found to have rifampicin-susceptible TB. Notably, 89% of 55 patients with very low bacillary loads on their initial Ultra had false RR-TB results, a significantly higher risk of false resistance compared to other bacillary load categories combined (risk ratio: 8.20; 95% confidence interval [CI]: 3.56\u201318.85; P &amp;lt; .001). Consequently, 53% (54\/101) of initial RR patients with available reference testing received unnecessary RR-TB treatment.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Ultra represents a valuable tool for rapid RR-TB detection; however, in low prevalence settings its low positive predictive value for RR detection is largely driven by samples with very low bacillary loads. As programs expand active case-finding and early detection of asymptomatic disease, the proportion of TB detected with very low bacillary load will increase. Diagnostic algorithms require adjustments to prevent unnecessary RR-TB treatment.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/cid\/ciaf132","type":"journal-article","created":{"date-parts":[[2025,3,23]],"date-time":"2025-03-23T02:15:28Z","timestamp":1742696128000},"page":"372-378","source":"Crossref","is-referenced-by-count":10,"title":["Paucibacillary Tuberculosis Drives the Low Positive Predictive Value of Xpert MTB\/RIF Ultra for Rifampicin Resistance Detection in Low-Prevalence Settings"],"prefix":"10.1093","volume":"81","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7543-3386","authenticated-orcid":false,"given":"Isabel","family":"Cuella-Martin","sequence":"first","affiliation":[{"name":"Mycobacteriology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine , Antwerp ,","place":["Belgium"]},{"name":"Department of Biomedical Sciences, Antwerp University , Antwerp 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Services, Rwanda Biomedical Centre , Kigali ,","place":["Rwanda"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hosee","family":"Niyompano","sequence":"additional","affiliation":[{"name":"National Reference Laboratory Division, Department of Biomedical Services, Rwanda Biomedical Centre , Kigali ,","place":["Rwanda"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0000-4685-7972","authenticated-orcid":false,"given":"Jelle","family":"Keysers","sequence":"additional","affiliation":[{"name":"Mycobacteriology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine , Antwerp ,","place":["Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Willem Bram","family":"De Rijk","sequence":"additional","affiliation":[{"name":"Mycobacteriology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine , Antwerp ,","place":["Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wim","family":"Mulders","sequence":"additional","affiliation":[{"name":"Mycobacteriology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine , Antwerp ,","place":["Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2824-3499","authenticated-orcid":false,"given":"Ellen M H","family":"Mitchell","sequence":"additional","affiliation":[{"name":"Mycobacterial Diseases and Neglected Tropical Diseases Unit, Department of Public Health, Institute of Tropical Medicine , Antwerp ,","place":["Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1205-1484","authenticated-orcid":false,"given":"Tom","family":"Decroo","sequence":"additional","affiliation":[{"name":"HIV and Tuberculosis Unit, Department of Clinical Sciences, Institute of Tropical Medicine , Antwerp ,","place":["Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yves Mucyo","family":"Habimana","sequence":"additional","affiliation":[{"name":"Tuberculosis and Other Respiratory Diseases Division, Rwanda Biomedical Centre , Kigali ,","place":["Rwanda"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patrick","family":"Migambi","sequence":"additional","affiliation":[{"name":"Tuberculosis and Other Respiratory Diseases Division, Rwanda Biomedical Centre , Kigali ,","place":["Rwanda"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Claude Mambo","family":"Muvunyi","sequence":"additional","affiliation":[{"name":"Department of Clinical Biology, Rwanda Biomedical Centre , Kigali ,","place":["Rwanda"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1017-4675","authenticated-orcid":false,"given":"Bouke C","family":"de Jong","sequence":"additional","affiliation":[{"name":"Mycobacteriology 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