Antagonistic activity against Salmonella infection in vitro and in vivo for two Lactobacillus strains from swine and poultry.

In this study, we isolated two lactobacillus strains, i.e., strain LAP5 and LF33, from swine and poultry, respectively, and showed that both strains were acid as well as bile tolerant and were able to adhere to the cultured human intestinal cell lines, such as Int-407 and Caco-2 cells, and to the intestinal epithelium cells isolated from swine, poultry and mouse (BALB/c). Both of these LAB strains were shown to inhibit the growth of Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Bacillus cereus. When these two LAB strains were evaluated for their antagonistic activity against Salmonella (S. typhimurium) invasion to cultured human intestinal cell line Int-407 and to mouse (BALB/c) liver and spleen, these two LAB strains were found to have significant antagonistic effect.

Pulsed field gel electrophoresis for animal Salmonella enterica serovar Typhimurium isolates in Taiwan.

Salmonella enterica subspecies enterica serovar Typhimurium is a common pathogen for humans and animals. In order to trace the clonal relationship and to find the circulating strains between human and animal isolates, chromosomal DNAs from 87 serovar Typhimurium strains isolated from animals (pigs were the majority) were subjected to XbaI and SpeI digestion and pulsed field gel electrophoresis (PFGE). For the 87 animal isolates, 38 PFGE pattern combinations were obtained. As the subtyping results from animal isolates were compared with those from the 45 human isolates, it was found that 14 of the animal isolates and 13 of the human isolates shared a common PFGE pattern combination, i.e., pattern XgSf (or called X5S4). When these human and animal isolates were subjected to antibiotic susceptibility test using 11 antibiotics, it was found that strains of pattern XgSf (X5S4) belong to a common antibiogram pattern which is tetracycline, gentamicin, ampicillin, streptomycin and chloramphenicol resistant. Since most of the animal and human strains in pattern XgSf were originally isolated from various areas over different years, strains of this PFGE pattern may be the most epidemic strains which circulating between human and animal sources.