{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T22:01:36Z","timestamp":1791842496480,"version":"4.3.4"},"reference-count":46,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2025,3,12]],"date-time":"2025-03-12T00:00:00Z","timestamp":1741737600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"German Federal Ministry of Education and Research (BMBF)","award":["01KI1726D"],"award-info":[{"award-number":["01KI1726D"]}]},{"name":"German Federal Ministry of Education and Research (BMBF)","award":["01KI2008A"],"award-info":[{"award-number":["01KI2008A"]}]},{"name":"German Federal Ministry of Education and Research (BMBF)","award":["GRK 473 2740\/447268119"],"award-info":[{"award-number":["GRK 473 2740\/447268119"]}]},{"DOI":"10.13039\/100004807","name":"DFG","doi-asserted-by":"publisher","award":["01KI1726D"],"award-info":[{"award-number":["01KI1726D"]}],"id":[{"id":"10.13039\/100004807","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100004807","name":"DFG","doi-asserted-by":"publisher","award":["01KI2008A"],"award-info":[{"award-number":["01KI2008A"]}],"id":[{"id":"10.13039\/100004807","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100004807","name":"DFG","doi-asserted-by":"publisher","award":["GRK 473 2740\/447268119"],"award-info":[{"award-number":["GRK 473 2740\/447268119"]}],"id":[{"id":"10.13039\/100004807","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Q fever is a zoonotic disease caused by the obligate intracellular bacterium Coxiella (C.) burnetii. Human infections occur mainly via inhalation, but infections via the oral route have been observed. Gastric acidic conditions (pH 2\u20134) are the first defense mechanism to limit food-associated infections. In this study, we tested the ability of C. burnetii to survive extremely acidic conditions (pH 2\u20133) to assess the risk of oral infection in humans. We treated different C. burnetii strains with different pH values and calculated the recovery rate by counting colony-forming units. The analysis of an additional eight C. burnetii strains showed that some strains are acid-resistant, while others are not. Importantly, the presence of pepsin, an endopeptidase and the main digestive enzyme in the gastrointestinal tract, increases the survival rate of C. burnetii. Similarly, the presence of milk might also increase the survival rate. These results suggest that oral infections by C. burnetii are possible and depend on the bacterial strain and the stomach microenvironment. Consequently, the digestive infection route of C.\u00a0burnetii could play a role in the transmission of the pathogen.<\/jats:p>","DOI":"10.3390\/pathogens14030272","type":"journal-article","created":{"date-parts":[[2025,3,12]],"date-time":"2025-03-12T10:45:06Z","timestamp":1741776306000},"page":"272","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Acid Tolerance of Coxiella burnetii Is Strain-Specific and Might Depend on Stomach Content"],"prefix":"10.3390","volume":"14","author":[{"given":"Katharina","family":"Sobotta","sequence":"first","affiliation":[{"name":"Institute of Medical Microbiology, Am Klinikum 1, 07747 Jena, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3810-4457","authenticated-orcid":false,"given":"Jan","family":"Schulze-Luehrmann","sequence":"additional","affiliation":[{"name":"Mikrobiologisches Institut, Universit\u00e4tsklinikum Erlangen, Friedrich-Alexander-Universit\u00e4t Erlangen-N\u00fcrnberg, 91054 Erlangen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martha","family":"\u00d6lke","sequence":"additional","affiliation":[{"name":"Mikrobiologisches Institut, Universit\u00e4tsklinikum Erlangen, Friedrich-Alexander-Universit\u00e4t Erlangen-N\u00fcrnberg, 91054 Erlangen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6743-1089","authenticated-orcid":false,"given":"Katharina","family":"Boden","sequence":"additional","affiliation":[{"name":"Institute of Medical Microbiology, Am Klinikum 1, 07747 Jena, Germany"},{"name":"Synlab MVZ Weiden GmbH, MVZ Thuringia, Ernst-Ruska-Ring 15, 07745 Jena, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anja","family":"L\u00fchrmann","sequence":"additional","affiliation":[{"name":"Mikrobiologisches Institut, Universit\u00e4tsklinikum Erlangen, Friedrich-Alexander-Universit\u00e4t Erlangen-N\u00fcrnberg, 91054 Erlangen, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,3,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"518","DOI":"10.1128\/CMR.12.4.518","article-title":"Q fever","volume":"12","author":"Maurin","year":"1999","journal-title":"Clin. 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