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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #410021
Research Project: Ecological Factors that Enable Colonization, Retention, and Dispersal of Foodborne Pathogens and Intervention Strategies to Control the Pathogens and Antimicrobial Resistance in Cattle and Swine

Location: Food and Feed Safety Research

Title: Chlortetracycline concentration impact on Salmonella Typhimurium sustainability in the presence of porcine gastrointestinal tract bacteria maintained in continuous culture

Author
item DITTOE, DANA - University Of Wyoming
item Anderson, Robin
item Poole, Toni
item Crippen, Tawni - Tc
item Harvey, Roger
item RICKE, STEVEN - University Of Wisconsin

Submitted to: Pathogens
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2023
Publication Date: 12/15/2023
Citation: Dittoe, D.K., Anderson, R.C., Poole, T.L., Crippen, T.L., Harvey, R.B., Ricke, S.C. 2023. Chlortetracycline concentration impact on Salmonella Typhimurium sustainability in the presence of porcine gastrointestinal tract bacteria maintained in continuous culture. Pathogens. 12. Article 1454. https://doi.org/10.3390/pathogens12121454.
DOI: https://doi.org/10.3390/pathogens12121454

Interpretive Summary: Concern exists that the continued use of antibiotics in animal feeds may lead to an increased prevalence of resistant bacteria within the host animal's gastrointestinal tract. To evaluate the effect of the antibiotic chlortetracycline on the persistence of the foodborne pathogen Salmonella Typhimurium within a diverse population of swine cecal bacteria, we cultured a mixed population of cecal bacteria, without or with added chlortetracycline. Under the conditions of this study, chlortetracycline-resistant Salmonella Typhimurium persisted longer within the mixed populations of swine gut bacteria than did the chlortetracycline-susceptible Salmonella Typhimurium even in the absence of added chlortetracycline. These results provide important new information regarding the competitive advantage provided to a resistant bacterium and highlight the need to find new non-antibiotic control strategies for American swine farmers.

Technical Abstract: Concern exists that the continued use of antibiotics in animal feeds may lead to an increased prevalence of resistant bacteria within the host animal's gastrointestinal tract. To evaluate the effect of chlortetracycline on the persistence of Salmonella enterica serotype Typhimurium within a diverse population of porcine cecal bacteria, we cultured a mixed population of cecal bacteria, without or with added chlortetracycline. When grown at a 24-hour vessel turnover rate, chlortetracycline-susceptible Salmonella Typhimurium exhibited more than 2.5 times faster (P < 0.05) disappearance rates that theoretically expected (0.301 log10 colony forming unit/mL per day) but did not differ whether treated or not with 55 mg chlortetracycline/L. Chlortetracycline-resistant Salmonella Typhimurium were not recovered from any of these cultures. When the mixed cultures were inoculated with a chlortetracycline-resistant Salmonella Typhimurium, rates of disappearance were nearly 2 times slower (P < 0.05) to that observed earlier with chlortetracycline-susceptible Salmonella Typhimurium and cultures persisted at > 2 log10 colony forming units/ml for up to 14 days of treatment with 110 mg chlortetracycline/L. Under the conditions of this study chlortetracycline-resistant Salmonella Typhimurium were competitively enabled to persist longer within the mixed populations of porcine gut bacteria than the chlortetracycline-susceptible Salmonella Typhimurium regardless of the presence or absence of added chlortetracycline.