In vitro inhibition of Salmonella enterica serovars choleraesuis and typhimurium, Escherichia coli F-18, and Escherichia coli O157:H7 by a porcine continuous-flow competitive exclusion culture.
A competitive exclusion (CE) culture of porcine cecal bacteria was developed as a continuous-flow culture in chemostats, was designated RPCF, and was used as a model to determine its usefulness against in vitro colonization by Salmonella enterica serovars Typhimurium and Choleraesuis, Escherichia coli strain F-18, and E. coli serotype O157:H7 (933). Chemostats with or without RPCF were inoculated with 10(6) colony-forming units (CFU)/ml of Typhimurium, Choleraesuis, F-18, or O157:H7. Chemostats were sampled for salmonellae and E. coli at 15 min, 7 h, and every 24 h thereafter. In control chemostats without RPCF, Typhimurium, Choleraesuis, F-18, and O157:H7 rapidly established colonization and had concentrations of 10(6) CFU/ml for 96-120 h post-inoculation. In the chemostats that contained RPCF, reductions (P < 0.05) of Choleraesuis, F-18, and O157:H7 were observed at 24 h post-inoculation. Typhimurium was decreased (P < 0.05) at 48 h post-inoculation, and by 120 h post-inoculation, all chemostats were negative for the four challenge microorganisms. These results demonstrate that RPCF cultures were able to inhibit the growth of Typhimurium, Choleraesuis, and E. coli strains F-18 and O157:H7 in vitro and suggest the potential for the use of CE in swine to prevent disease induced by these microorganisms.
Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, College Station, TX 77845, USA. harvey@ffsru.tamu.edu
Roger B
RB
Harvey
Robert E
RE
Droleskey
Michael E
ME
Hume
Robin C
RC
Anderson
Kenneth J
KJ
Genovese
Kate
K
Andrews
David J
DJ
Nisbet
D000818:Animals; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000254:growth & development / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000209:etiology; D019453:Escherichia coli O157 / Q000254:growth & development / Q000472:pathogenicity*; D066298:In Vitro Techniques; D012481:Salmonella Infections, Animal / Q000209:etiology; D019779:Salmonella enterica / Q000254:growth & development / Q000472:pathogenicity*; D012486:Salmonella typhimurium / Q000254:growth & development / Q000472:pathogenicity*; D013552:Swine; D013553:Swine Diseases / Q000209:etiology