biostudies-literatureMarkovich YMinisterio de Ciencia, Innovación y UniversidadesUniversidad CEU Cardenal HerreraInstitut PasteurGeneralitat Valencianae70169https://www.ebi.ac.uk/biostudies/studies/S-EPMC12415317biostudies-literatureUnknown27(9)Listeria monocytogenes is a saprophytic bacterium and a foodborne pathogen of humans and animals. Little is known about its distribution and genetic diversity across different environments within the same geographical region. We conducted a large-scale longitudinal study in southeastern Spain monitoring Listeria spp. in untreated wastewater, ruminant farms, and natural environments over four seasons (N = 1490 samples, N = 545 isolates) and in food and food-processing environments (N = 7395 samples, N = 255 isolates). Listeria spp. were more abundant in host-associated than natural environments, and non-pathogenic Listeria were more prevalent than L. monocytogenes in both niches. L. monocytogenes was detected in 42.7%, 11.4%, 4.2%, and 3.4% of wastewater, ruminant farms, natural environmentEnvironmental microbiologyPredominance of L. monocytogenes Lineage I Clones in Wastewater, Ruminants, and Natural Environments.PMC12415317RYC2021-032245-IRYC-2018-024985-IPID2023-152404OB-I00CIAICO/2023/053INDI21/25INDI 22/44Predoctoral contract Yuval MarkovichPID2022-137961OB-I00Ortola SLecuit MGomez-Martin AQuereda JJMarkovich YVales GThouvenot PMoura AGomis JLeclercq APerot PTessaud-Rita NYanez MAPalacios-Gorba CBracq-Dieye HfalsePredominance of L. monocytogenes Lineage I Clones in Wastewater, Ruminants, and Natural Environments.Listeria monocytogenes is a saprophytic bacterium and a foodborne pathogen of humans and animals. Little is known about its distribution and genetic diversity across different environments within the same geographical region. We conducted a large-scale longitudinal study in southeastern Spain monitoring Listeria spp. in untreated wastewater, ruminant farms, and natural environments over four seasons (N = 1490 samples, N = 545 isolates) and in food and food-processing environments (N = 7395 samples, N = 255 isolates). Listeria spp. were more abundant in host-associated than natural environments, and non-pathogenic Listeria were more prevalent than L. monocytogenes in both niches. L. monocytogenes was detected in 42.7%, 11.4%, 4.2%, and 3.4% of wastewater, ruminant farms, natural environment2025-01-01T00:00:00Z2025 Sep2026-06-02T02:27:56.526Z2026-04-13T03:12:11.382ZS-EPMC124153174091616510.1111/1462-2920.70169