{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"omics_type":["Unknown"],"volume":["9"],"submitter":["Hirsch C"],"pubmed_abstract":["<h4>Introduction</h4>Bacterial bronchopneumonia (BP) has been associated with purchasing cattle through auction markets. However, whether auction markets are a source of BP-associated bacterial pathogens is unknown. This study evaluated prevalence, antimicrobial susceptibility, and genetic relatedness (using pulsed-field gel electrophoresis, PFGE) of <i>Mannheimia haemolytica, Pasteurella multocida</i>, and <i>Histophilus somni</i> isolated from cattle either transported to an auction market prior to feedlot placement (AUC), or directly to a feedlot from a farm (RANC).<h4>Methods</h4>Two groups of cattle were enrolled (N = 30 per group) from two separate farms with 15 animals from an individual farm designated as AUC or RANC. Deep nasal swab (DNS) and trans-tracheal aspirates (TTA) were collected on day 0 at weaning (T0) and on day 2 at on-arrival processing at the feedlot (T1). The DNS were also collected on day 9 (T2) and day 30 (T3) after arrival at the feedlot.<h4>Results and discussion</h4>In both TTA and DNS, prevalence of bacteria did not differ between AUC and RANC groups (<i>P</i> > 0.05). None of the bacteria isolated at T0 were resistant to antimicrobials and diversity of all bacteria was greatest at T0 and T1. In Group 1 cattle, 100% of <i>P. multocida</i> isolated at T2 and T3 were multi-drug resistant. These isolates were highly related (>90%) according to PFGE, with most being clones. Though limited in size, results for animals evaluated in this study suggested that auction markets were not a major source of resistant BP pathogens, however, horizontal transmission of a multi-resistant strain of <i>P. multocida</i> occurred in a feedlot. Spread of resistant <i>P. multocida</i> was likely due to the selective pressures imposed by feedlot antimicrobial use and encoded resistance by the bacteria."],"journal":["Frontiers in veterinary science"],"pagination":["1026470"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC9902877"],"repository":["biostudies-literature"],"pubmed_title":["Comparison of pathogenic bacteria in the upper and lower respiratory tracts of cattle either directly transported to a feedlot or co-mingled at auction markets prior to feedlot placement."],"pmcid":["PMC9902877"],"pubmed_authors":["Hirsch C","Alexander TW","Timsit E","Uddin MS","Guan LL"],"additional_accession":[]},"is_claimable":false,"name":"Comparison of pathogenic bacteria in the upper and lower respiratory tracts of cattle either directly transported to a feedlot or co-mingled at auction markets prior to feedlot placement.","description":"<h4>Introduction</h4>Bacterial bronchopneumonia (BP) has been associated with purchasing cattle through auction markets. However, whether auction markets are a source of BP-associated bacterial pathogens is unknown. This study evaluated prevalence, antimicrobial susceptibility, and genetic relatedness (using pulsed-field gel electrophoresis, PFGE) of <i>Mannheimia haemolytica, Pasteurella multocida</i>, and <i>Histophilus somni</i> isolated from cattle either transported to an auction market prior to feedlot placement (AUC), or directly to a feedlot from a farm (RANC).<h4>Methods</h4>Two groups of cattle were enrolled (N = 30 per group) from two separate farms with 15 animals from an individual farm designated as AUC or RANC. Deep nasal swab (DNS) and trans-tracheal aspirates (TTA) were collected on day 0 at weaning (T0) and on day 2 at on-arrival processing at the feedlot (T1). The DNS were also collected on day 9 (T2) and day 30 (T3) after arrival at the feedlot.<h4>Results and discussion</h4>In both TTA and DNS, prevalence of bacteria did not differ between AUC and RANC groups (<i>P</i> > 0.05). None of the bacteria isolated at T0 were resistant to antimicrobials and diversity of all bacteria was greatest at T0 and T1. In Group 1 cattle, 100% of <i>P. multocida</i> isolated at T2 and T3 were multi-drug resistant. These isolates were highly related (>90%) according to PFGE, with most being clones. Though limited in size, results for animals evaluated in this study suggested that auction markets were not a major source of resistant BP pathogens, however, horizontal transmission of a multi-resistant strain of <i>P. multocida</i> occurred in a feedlot. Spread of resistant <i>P. multocida</i> was likely due to the selective pressures imposed by feedlot antimicrobial use and encoded resistance by the bacteria.","dates":{"release":"2022-01-01T00:00:00Z","publication":"2022","modification":"2025-04-04T18:43:47.139Z","creation":"2025-04-04T18:43:47.139Z"},"accession":"S-EPMC9902877","cross_references":{"pubmed":["36761402"],"doi":["10.3389/fvets.2022.1026470"]}}