Antagonistic activity of Lactobacillus acidophilus LA10 against Salmonella enterica serovar Enteritidis SE86 in mice

Salmonella enterica serovar Enteritidis is one of the main pathogens responsible for foodborne illness in Brazil. Probiotic bacteria can play a role in defense and recovery from enteropathogenic -infections. In this study, the ability of Lactobacillus acidophilus LA10 to colonise and exert anta-gonistic effects in the gastrointestinal tract was tested before and during experimental infection in conventional mice contaminated with S. Enteritidis (SE86). A dose of 0.1 mL containing 10(8) viable cells of SE86 and L. acidophilus LA10 was orally administered by gavage to mice. The experiment was divided into groups. As a negative control, Group 1 was administered only sterile saline solution. As a positive control, Group 2 was administered only SE86. Group 3 was first administered SE86, and after 10 days, treated with L. acidophilus LA10. Group 4 was first administered L. acidophilus LA10,and after 10 days, challenged with SE86.The results demonstrated that a significant number of SE86 cells were able to colonize the gastrointestinal tract of mice, specifically in the colon and ileum. L. acidophilus LA10 demonstrated an antagonistic effect against SE86, with better results observed for Group 3 over Group 4. Thus, L. acidophilus LA10 shows potential antagonistic effects against S. Enteritidis SE86, especially if administered after infection.

Protection by Lactobacillus acidophilus UFV-H2B20 against experimental oral infection with Salmonella enterica subsp. Enterica Ser. Typhimurium in gnotobiotic and conventional mice

The ability of Lactobacillus acidophilus UFV-H2B20 to antagonize Salmonella enterica subsp. enterica ser. Typhimurium and to reduce the pathological consequences for the host was determining using conventional and gnotobiotic animals. Conventional NIH mice received daily by gavage a 0.1 ml suspension containing about 10(8) cfu L. acidophilus UFV-H2B20 and germfree animals received a single 0.1 ml dose. The gnotobiotic and conventional groups were infected orally with 10(2) and 10(5) cfu of S. Typhimurium, respectively, 7 days after the beginning of treatment. Control groups were treated with sterile saline instead of Lactobacillus. Survival data showed a protective effect against the pathogenic bacteria in both conventional and gnotobiotic Lactobacillus-treated mice. L. acidophilus UFV-H2B20 colonized the digestive tract of gnotobiotic mice and the number of viable cells ranged from 10(9) to 10(10) cfu/g of faeces. In both experimental and control gnotobiotic animals, S. Typhimurium became rapidly established at a level ranging from 108 to 1010 cfu/g of faeces and remained at high levels until the animals died or were sacrificed. In conclusion, the previous treatment of mice with L. acidophilus UFV-H2B20 protects the animals against the experimental infection with S. Typhimurium but this protection was not due to the reduction of the pathogenic populations in the intestines.(au)

Análisis de la acción antibacteriana in vitro de una amalgama fluorada / Analysis of the in vitro antibacterial action of a fluoride amalgam

A una aleación de amalgama de plata convencional se le incorporó un 1% de fluoruro estañoso, para comprobar In Vitro, si presenta acción antibacteriana contra el S. mutans y contra el Lactobacillus acidophilus. Se sembraron 13 placas de Petri con S. mutans y 12 placas de Petri con Lactobacillus, en ambos casos se depositó una probeta de amalgama fluorada y otra convencional. Los resultados muestran que se producía halo de inhibición con la amalgama fluorada, así en la amalgama convencional. El promedio de halo de inhibición en las placas con S. mutans fue 1,7 mm, en las placas con Lactobacillus el promedio fue de 2,4 mm. Se demuestra cualitativamente que la amalgama fluorada podría tener acción antibacteriana In Vitro a diferencia de la amalgama convencional que no la presenta