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[afro-nets] Open Learning Web site on Enteric pathogens (2)

  • From: "Salvatore Rubino" <rubino@uniss.it>
  • Date: Fri, 12 May 2006 11:37:42 +0200

Open Learning Web site on Enteric pathogens (2)

Dear Friends of the Open Learning Web site on Enteric pathogens

A new lecture is available at:

Mónica Olivares, Mª Paz Díaz-Ropero, Federico Lara-Villoslada, Saleta
Sierra, Jordi Xaus (Spain).
Immunology and Animal Science Department, Puleva Biotech S.A., Camino de Purchil 66, 18004, Granada, Spain.molivares@pulevabiotech.es

New probiotic strains that enhance the intestinal function of healthy
adults. The optimal well-being of the organism depends on a correct
balance between the different bacterial species of the intestinal
microbiota. Recently the use of probiotic strains (particularly
lactobacilli and bifidobacteria) has been promoted as a means to
balance the gut microbiota and, in fact, their potential preventive and
therapeutical effects have received renewed research and industrial
interest. Two new Lactobacillus strains have been recently isolated and
characterized: Lactobacillus gasseri CECT5714 isolated from breast milk
and Lactobacillus coryniformis CECT5711 isolated from artisan goat´s
cheese. In order to investigate the effect of a fermented product
containing these two new strains on intestinal function in healthy
human, a randomized, double blind, placebo-controlled human clinical
trial was performed involving 30 healthy adults. The volunteers were
randomly distributed into two groups, one receiving a standard yogurt
and the other a similar dairy fermented product in which the
Lactobacillus delbreuckii subsp. bulgaricus yogurt strain had been
replaced by a combination of the probiotic strains L. gasseri CECT5714
and L. coryniformis CECT5711. The volunteers that received the
probiotic strains reported no adverse effects in the hosts and the
strains could be isolated from their faeces at a relatively high level.
In fact, the concentration of faecal lactic acid bacteria significantly
increased in the probiotic group. Additionally, the oral administration
of the probiotic strains led to an improvement of parameters such as
the production of short-chain fatty acids, the faecal moisture and the
frequency and volume of the stools. As a result, the volunteers
assigned to the probiotic group perceived a clear improvement in their
intestinal habits The study revealed that probiotics may exert a
positive effect on intestinal function. In addition to this it was
detected an increase in IgA in faeces that might contribute to the
defence against infections. The intestinal mucosa constitutes the main
interface with the external environment and, as a consequence, is the
main entrance for foreign substances and microorganisms. Since
microbiota exert an important role in the defence against infections in
vitro and in vivo assays have been carried out in order to investigate
the antimicrobial potential of the two new probiotic strains. The
results showed that both strains displayed antibacterial properties
such as inhibition of pathogen growth, inhibition of the pathogen
adhesion to mucins or induction of mucin production. In vivo assays in
a murine infection model revealed the oral administration of both
strain protect mice against Salmonella infection in a mice model.
Therefore the oral consumption of L. gasseri CECT5714 and L.
coryniformis CECT5711 improve the intestinal function of the host and
could contribute to protect against intestinal infections by increasing
the immune response and by antimicrobial mechanisms that interfere the
adhesion of the entero-pathogenic bacteria.

Ciao Salvatore Rubino

Prof. Salvatore Rubino
Dip. di Scienze Biomediche
V.le San Pietro 43/b
07100 Sassari (Italy)
Fax: +39-79-212345
Cell: +39-3383865292