{"doi":"10.1007/s42770-025-01634-9","title":"High frequency of chromosomal polymyxin resistance in Escherichia coli isolated from dairy farm animals and genomic analysis of mcr-1-positive strain","abstract":null,"journal":"Brazilian Journal of Microbiology","year":2025,"id":646025,"datarank":0.24141568686511508,"base_score":1.6094379124341003,"endowment":1.6094379124341003,"self_citation_contribution":0.24141568686511508,"citation_network_contribution":0.0,"self_endowment_contribution":0.24141568686511508,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":4,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1682416,"name":"Vinícius Sanches Rosa","orcid":null,"position":1,"is_corresponding":false},{"id":1682417,"name":"Gustavo Henrique Batista Lara","orcid":null,"position":2,"is_corresponding":false},{"id":1594447,"name":"Márcio Garcia Ribeiro","orcid":null,"position":3,"is_corresponding":false},{"id":1682420,"name":"Domingos da Silva Leite","orcid":null,"position":4,"is_corresponding":false},{"id":1682414,"name":"Taila dos Santos Alves","orcid":"0000-0002-5672-509X","position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"High frequency of chromosomal polymyxin resistance in Escherichia coli isolated from dairy farm animals and genomic analysis of mcr-1-positive strain","abstract":"Escherichia coli strains are naturally susceptible to polymyxins. The frequency of polymyxin resistance in E. coli associated with chromosomal mutations is usually low (0.2-0.6%). Here, we report polymyxin-resistant E. coli strains isolated from flies (Diptera: Muscomorpha) and animals (bovine, equine, canine, and sheep) cohabitants on two dairy farms, A and B (Botucatu, State of Sao Paulo, Brazil), in 2015. We isolated 877 E. coli from the external surface of flies and healthy animal feces. The screening of polymyxin-resistant E. coli was performed using MacConkey agar with polymyxin B (2 µg/mL). We detected a high percentage of polymyxin-resistant isolates from flies (33.33%; 66/198) and farm animals (46.09%; 313/679). Fisher's exact test revealed no associations between polymyxin resistant and multidrug resistant strains. We investigated mcr genes (mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5) using PCR, and five E. coli from calves (farm B) present the mcr-1 gene. Sanger sequencing and conjugation assays were performed for gene confirmation. All five mcr-1-positive E. coli showed fingerprints more than 80% similar assayed by pulsed-field gel electrophoresis. The minimum inhibitory concentrations (MICs) for polymyxin B against mcr-1-positive E. coli were 4 µg/mL (two strains), and 8 µg/mL (three strains). Whole-genome sequencing showed mcr-1.1 gene in the IncX4 plasmid and a class 1 integron unusual harboring sul3 and qacL as a non-variable structure. In Brazil, the therapeutic use of polymyxin is allowed, but stewardship in dairy cattle is uncommon; thus, our data indicate a probable selection of polymyxin-resistant strains related to environmental pressure.","is_dataset_classified":null,"base_score":1.6094379124341003,"endowment":1.6094379124341003,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"39964669","pmcid":"PMC12095835","openalex_id":"https://openalex.org/W4407706725","authors":[],"funders":[{"funder_name":"Fundação de Amparo à Pesquisa do Estado de São Paulo","grant_id":"2015/15425-2","title":null}],"total_grants":1,"fwci":1.2683,"citation_percentile":0.76620329,"influential_citations":0,"citation_trend":[{"year":2025,"count":1},{"year":2026,"count":3}],"oa_status":"green","license":"https://www.springernature.com/gp/researchers/text-and-data-mining","oa_locations":[{"url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC12095835/","host_type":"repository"},{"url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC12095835/","host_type":"repository"},{"url":"https://link.springer.com/content/pdf/10.1007/s42770-025-01634-9.pdf","host_type":"publisher"},{"url":"https://link.springer.com/article/10.1007/s42770-025-01634-9/fulltext.html","host_type":"publisher"},{"url":"https://doi.org/10.1007/s42770-025-01634-9","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/39964669","host_type":"repository"}],"fields_of_study":["Antibiotic Resistance in Bacteria","Pharmaceutical and Antibiotic Environmental Impacts","Bacterial Genetics and Biotechnology"],"mesh_terms":["Farms","Animals","Animals, Domestic","Anti-Bacterial Agents","Brazil","Cattle","Chromosomes, Bacterial","Diptera","Dogs","Escherichia coli","Escherichia coli Infections","Feces","Horses","Microbial Sensitivity Tests","Polymyxins","Sheep","Drug Resistance, Bacterial","Escherichia coli Proteins"],"keywords":["Escherichia coli","Polymyxin","Strain (injury)","Microbiology","Biology","Plasmid","Polymyxin B","Veterinary medicine","Genetics","Antibiotics","Medicine","Gene","Cattle","Colistin","Flies","Antimicrobial resistance","Public Health","Milking Environment"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Zero hunger"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-09T11:12:09.961185Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}