title: Evaluation of the potential antimicrobial resistance transfer from a multi-drug resistant Escherichia coli to Salmonella in dairy calves.
abstract: Previous research conducted in our laboratory found a significant prevalence of multi-drug resistant (MDR) Salmonella and MDR Escherichia coli (MDR EC) in dairy calves and suggests that the MDR EC population may be an important reservoir for resistance elements that could potentially transfer to Salmonella. Therefore, the objective of the current research was to determine if resistance transfers from MDR EC to susceptible strains of inoculated Salmonella. The experiment utilized Holstein calves (approximately 3 weeks old) naturally colonized with MDR EC and fecal culture negative for Salmonella. Fecal samples were collected for culture of Salmonella and MDR EC throughout the experiment following experimental inoculation with the susceptible Salmonella strains. Results initially suggested that resistance did transfer from the MDR E. coli to the inoculated strains of Salmonella, with these stains demonstrating resistance to multiple antibiotics following in vivo exposure to MDR EC. However, serogrouping and serotyping results from a portion of the Salmonella isolates recovered from the calves post-challenge, identified two new strains of Salmonella; therefore transfer of resistance was not demonstrated under these experimental conditions.
authors.affiliation: Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, USDA-ARS, 2881 F&B Road, College Station, TX, 77845, USA. tom.edrington@ars.usda.gov
authors.forename: T S
authors.initials: TS
authors.lastname: Edrington
authors.forename: R L
authors.initials: RL
authors.lastname: Farrow
authors.forename: M E
authors.initials: ME
authors.lastname: Hume
authors.forename: P N
authors.initials: PN
authors.lastname: Anderson
authors.forename: G R
authors.initials: GR
authors.lastname: Hagevoort
authors.forename: D J
authors.initials: DJ
authors.lastname: Caldwell
authors.forename: T R
authors.initials: TR
authors.lastname: Callaway
authors.forename: R C
authors.initials: RC
authors.lastname: Anderson
authors.forename: D J
authors.initials: DJ
authors.lastname: Nisbet
mesh_terms: D000818:Animals; D002417:Cattle; D004195:Disease Models, Animal; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics*; D004927:Escherichia coli Infections / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000382:microbiology; D022761:Gene Transfer, Horizontal; D012475:Salmonella / Q000187:drug effects* / Q000235:genetics*; D012481:Salmonella Infections, Animal / Q000382:microbiology