6 research outputs found
Protective Effect of Vaginal Lactobacillus paracasei CRL 1289 against Urogenital Infection Produced by Staphylococcus aureus in a Mouse Animal Model
Urogenital infections of bacterial origin have a high incidence
among the world female population at reproductive age.
Lactobacilli, the predominant microorganisms of the healthy
vaginal microbiota, have shown a protective effect against the
colonization and overgrowth of urogenital pathogens that increased
the interest for including them into probiotics products assigned
to restore the urogenital balance. In the present work, we
determined in a mouse animal model the capability of Lactobacillus paracasei CRL 1289, a human vaginal strain with probiotic properties, to prevent the vaginal colonization of a uropathogenic strain of Staphylococcus aureus.
Six-week-old female BALB/c mice, synchronized in their estral
cycle, were intravaginally inoculated with two doses of 109 lactobacilli before challenging them with a single dose of 105 or 107 CFU of S. aureus. The vaginal colonization of both microorganisms and the effect on the vaginal structure were determined at 2, 5, and 7 days after pathogen
inoculation. Control mice and those challenged only with the
pathogen showed an insignificant lactobacilli population, whereas 105 lactobacilli/mL of vaginal homogenate were recovered at 2
days after challenge from the L. paracasei CRL 1289 and
the probiotic + pathogen groups, decreasing this number on the
following days. The treatment with L. paracasei CRL 1289
decreased significantly the number of staphylococci recovered at 2
and 5 days when mice were challenged only with 105 CFU of
pathogen. The inoculation of S. aureus produced a
remarkable inflammatory response and structural alterations in the
vaginal mucosa that decreases in a significant manner when the
mice were protected with L. paracasei CRL 1289. The
results obtained suggest that this particular Lactobacillus strain could prevent the onset of urogenital infections by interfering with the epithelial
colonization by uropathogenic S. aureus
Microbial flora variations in the respiratory tract of mice
A stable microbial system in the respiratory tract acts as an important
defense mechanism against pathogenic microorganisms. Perturbations in
this system may allow pathogens to establish. In an ecological
environment such as the respiratory tract, there are many diverse
factors that play a role in the establishment of the indigenous flora.
In the present work we studied the normal microbial flora of different
areas of the respiratory tract of mice and their evolution from the
time the mice were born. Our interest was to know which were the
dominant groups of microorganisms in each area, which were the first
capable of colonizing and which dominated over time to be used as
probiotic microorganisms. Our results show that Gram negative
facultatively anaerobic bacilli and strict anaerobic microorganisms
were the last ones to appear in the bronchia, while aerobic and Gram
positive cocci were present in all the areas of the respiratory tract.
The number of facultative aerobes and strict anaerobes were similar in
the nasal passage, pharynx instilled and trachea, but lower in
bronchia. The dominant species were Streptococcus viridans and
Staphylococcus saprophyticcus, followed by S. epidermidis, Lactobacilli
and S. cohnii I which were present on every studied days but at
different proportions. This paper is the first part of a research
topic investigating the protective effect of the indigenous flora
against pathogens using the mice as an experimental model
Microbial flora variations in the respiratory tract of mice
A stable microbial system in the respiratory tract acts as an important
defense mechanism against pathogenic microorganisms. Perturbations in
this system may allow pathogens to establish. In an ecological
environment such as the respiratory tract, there are many diverse
factors that play a role in the establishment of the indigenous flora.
In the present work we studied the normal microbial flora of different
areas of the respiratory tract of mice and their evolution from the
time the mice were born. Our interest was to know which were the
dominant groups of microorganisms in each area, which were the first
capable of colonizing and which dominated over time to be used as
probiotic microorganisms. Our results show that Gram negative
facultatively anaerobic bacilli and strict anaerobic microorganisms
were the last ones to appear in the bronchia, while aerobic and Gram
positive cocci were present in all the areas of the respiratory tract.
The number of facultative aerobes and strict anaerobes were similar in
the nasal passage, pharynx instilled and trachea, but lower in
bronchia. The dominant species were Streptococcus viridans and
Staphylococcus saprophyticcus, followed by S. epidermidis, Lactobacilli
and S. cohnii I which were present on every studied days but at
different proportions. This paper is the first part of a research
topic investigating the protective effect of the indigenous flora
against pathogens using the mice as an experimental model