{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T13:57:09Z","timestamp":1791295029016,"version":"4.1.0"},"reference-count":87,"publisher":"American Society for Microbiology","issue":"10","license":[{"start":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T00:00:00Z","timestamp":1791244800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T00:00:00Z","timestamp":1791244800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"name":"Bundesanstalt fuer Landwirtschaft und Ernaehrung","award":["2821OE035"],"award-info":[{"award-number":["2821OE035"]}]}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Microbiol Spectr"],"published-print":{"date-parts":[[2026,10,6]]},"abstract":"ABSTRACT<\/jats:title>\n \n \n \n Widespread prevalence of fluoroquinolone-resistant\n Campylobacter<\/jats:italic>\n spp. in meat chicken is a major concern for public health. We examined the prevalence and antimicrobial resistance of thermotolerant\n Campylobacter<\/jats:italic>\n spp. in 14 German organic meat chicken farms rearing slow-growing broilers, male layer hybrids, or dual-purpose cockerels in a longitudinal study. Most farms participated with four subsequent flocks. Each flock was sampled three times: approximately 1 month after hatching (before outdoor access), 2 weeks after first outdoor access, and at the end of the fattening period. Strikingly, most flocks were already\n Campylobacter<\/jats:italic>\n -positive before first outdoor access. At the end of the fattening period, 98% of all flocks were positive, with\n C. jejuni<\/jats:italic>\n being the predominant species. Antimicrobial resistance of 405\n C. jejuni<\/jats:italic>\n and 79\n C. coli<\/jats:italic>\n revealed overall high levels of ciprofloxacin and tetracycline resistance but absence of macrolide resistance. Ertapenem resistance was observed in individual farms. Generalized linear mixed models with random factors for farm and flocks within farm were used to assess predictors for the occurrence of ciprofloxacin- and tetracycline-resistant\n C. jejuni<\/jats:italic>\n . Season, fattening type, and the interaction of sampling time point and fattening type were significant fixed effects. Results for flocks within farms showed clustering effects (ICC\n CIP<\/jats:sub>\n = 0.447; ICC\n TET<\/jats:sub>\n = 0.412). Whole-genome sequencing of representative isolates confirmed great overall genetic variety, with farm- or fattening type-dependent dissemination of certain multi-locus sequence types. ST21 clonal complex for sequenced\n C. jejuni<\/jats:italic>\n and ST828 clonal complex for sequenced\n C. coli<\/jats:italic>\n were most commonly detected.\n <\/jats:p>\n \n IMPORTANCE<\/jats:title>\n \n Campylobacter<\/jats:italic>\n spp. are major foodborne pathogens associated with the consumption and handling of chicken meat. This longitudinal study provides further insight into the prevalence and antimicrobial resistance of thermotolerant\n C. jejuni<\/jats:italic>\n and\n C. coli<\/jats:italic>\n in German organic meat chicken farms, a growing sector with strict limitations on antibiotic treatment. We included multiple flocks of farms fattening either slow-growing broilers, male layer hybrids, or dual-purpose cockerels to account for a variety of fattening types. Consequently, we were able to demonstrate significant differences in the occurrence of ciprofloxacin- and tetracycline-resistant\n C. jejuni<\/jats:italic>\n based on fattening type, sampling time point, and season. Our findings highlight the successful spread and persistence of ciprofloxacin-, tetracycline-, and ertapenem-resistant\n C. jejuni<\/jats:italic>\n and\n C. coli<\/jats:italic>\n among all three types of organic meat chicken regardless of the lack of antibiotic treatment.\n <\/jats:p>\n <\/jats:sec>\n <\/jats:sec>","DOI":"10.1128\/spectrum.01012-26","type":"journal-article","created":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T13:41:30Z","timestamp":1788529290000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Longitudinal study of prevalence and antimicrobial resistance of thermotolerant\n Campylobacter<\/i>\n spp. in German organic meat chicken farms"],"prefix":"10.1128","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-5849-8903","authenticated-orcid":true,"given":"Anna Maria","family":"Korves-Wilm","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03k3ky186","id-type":"ROR","asserted-by":"publisher"}],"name":"Department Biological Safety, German Federal Institute for Risk Assessment","place":["Berlin, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8338-717X","authenticated-orcid":true,"given":"Kerstin","family":"Stingl","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03k3ky186","id-type":"ROR","asserted-by":"publisher"}],"name":"Department Biological Safety, German Federal Institute for Risk Assessment","place":["Berlin, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5725-7873","authenticated-orcid":true,"given":"Margret","family":"Krieger","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/04zc7p361","id-type":"ROR","asserted-by":"publisher"}],"name":"University of Kassel","place":["Witzenhausen, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8619-1498","authenticated-orcid":true,"given":"Mirjam","family":"Grobbel","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03k3ky186","id-type":"ROR","asserted-by":"publisher"}],"name":"Department Biological Safety, German Federal Institute for Risk Assessment","place":["Berlin, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2191-7569","authenticated-orcid":true,"given":"Bernd-Alois","family":"Tenhagen","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/03k3ky186","id-type":"ROR","asserted-by":"publisher"}],"name":"Department Biological Safety, German Federal Institute for Risk Assessment","place":["Berlin, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_6_2_2","doi-asserted-by":"publisher","DOI":"10.2903\/j.efsa.2025.9759"},{"key":"e_1_3_6_3_2","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.00006-15"},{"key":"e_1_3_6_4_2","doi-asserted-by":"publisher","DOI":"10.1093\/femspd\/ftac003"},{"key":"e_1_3_6_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jinf.2020.09.039"},{"key":"e_1_3_6_6_2","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-017-05227-x"},{"key":"e_1_3_6_7_2","unstructured":"World Health Organization (WHO). 2017. 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