{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T16:15:35Z","timestamp":1774887335761,"version":"3.50.1"},"reference-count":24,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T00:00:00Z","timestamp":1774828800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Consejer\u00eda de Sanidad y Bienestar Social de la Junta de Castilla y Le\u00f3n","award":["GRS 2720\/A1\/2023"],"award-info":[{"award-number":["GRS 2720\/A1\/2023"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biology"],"abstract":"<jats:p>Mycobacteria isolated only once in repeated sputum cultures are deemed colonizers that are not normally present in the lungs despite their ubiquitous presence in the environment. We have developed a sensitive and specific PCR assay to detect slow-growing mycobacteria in culture negative sputum and have found them in 30% of the samples obtained from individuals with clinical suspicion of tuberculosis or mycobacteriosis (n = 50) and in 45% of the samples from individuals with no suspicion (n = 49). As a negative control we have analyzed infections from an extra-pulmonary location, the urinary tract (n = 21), in which mycobacterioses are rare, and did not detect them. The load of bacteria in the lungs is kept low by the defense mechanisms of the host, and mycobacteria are not normally detected in sputum cultures. Their incidental isolation would not be a consequence of a new exposure to the microorganism but a sign of susceptibility to mycobacteriosis.<\/jats:p>","DOI":"10.3390\/biology15070553","type":"journal-article","created":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T15:20:47Z","timestamp":1774884047000},"page":"553","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["DNA from Slow-Growing Mycobacteria in Culture Negative Sputa Reveal Common Exposure to Mycobacteria"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2148-9936","authenticated-orcid":false,"given":"Ramiro","family":"L\u00f3pez-Medrano","sequence":"first","affiliation":[{"name":"Servicio de Microbiolog\u00eda Cl\u00ednica, Complejo Asistencial Universitario de Le\u00f3n, Gerencia Regional de Salud de Castilla y Le\u00f3n (SACYL), Altos de Nava, s\/n, 24071 Le\u00f3n, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0248-657X","authenticated-orcid":false,"given":"Miriam","family":"Retuerto-Guerrero","sequence":"additional","affiliation":[{"name":"Servicio de Reumatolog\u00eda, Complejo Asistencial Universitario de Le\u00f3n, Gerencia Regional de Salud de Castilla y Le\u00f3n (SACYL), Altos de Nava, s\/n, 24071 Le\u00f3n, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elizabeth","family":"de Freitas-Gonz\u00e1lez","sequence":"additional","affiliation":[{"name":"Servicio de Neumolog\u00eda, Complejo Asistencial Universitario de Le\u00f3n, Gerencia Regional de Salud de Castilla y Le\u00f3n (SACYL), Altos de Nava, s\/n, 24071 Le\u00f3n, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cristina","family":"Diez-Tasc\u00f3n","sequence":"additional","affiliation":[{"name":"Servicio de Anatom\u00eda Patol\u00f3gica, Complejo Asistencial Universitario de Le\u00f3n, Gerencia Regional de Salud de Castilla y Le\u00f3n (SACYL), Altos de Nava, s\/n, 24071 Le\u00f3n, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carmen del Mar","family":"P\u00e9rez-L\u00f3pez","sequence":"additional","affiliation":[{"name":"Laboratorio de Hematolog\u00eda, Complejo Asistencial Universitario de Le\u00f3n, Gerencia Regional de Salud de Castilla y Le\u00f3n (SACYL), Altos de Nava, s\/n, 24071 Le\u00f3n, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8793-0731","authenticated-orcid":false,"given":"Octavio Miguel","family":"Rivero-Lezcano","sequence":"additional","affiliation":[{"name":"Unidad de Investigaci\u00f3n, Complejo Asistencial Universitario de Le\u00f3n, Gerencia Regional de Salud de Castilla y Le\u00f3n (SACYL), Altos de Nava, s\/n, 24071 Le\u00f3n, Spain"},{"name":"Institute of Biomedical Research of Salamanca (IBSAL), 37007 Salamanca, Spain"},{"name":"Institute of Biomedicine (IBIOMED), University of Le\u00f3n, 24071 Le\u00f3n, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1016\/S0025-7125(16)34193-1","article-title":"Anonymous mycobacteria in pulmonary disease","volume":"43","author":"Runyon","year":"1959","journal-title":"Med. 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