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.
Harvey
Roger B
RB
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
Droleskey
Robert E
RE
Hume
Michael E
ME
Anderson
Robin C
RC
Genovese
Kenneth J
KJ
Andrews
Kate
K
Nisbet
David J
DJ
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