INVESTIGADORES
SALVUCCI Emiliano Jesus
congresos y reuniones científicas
Título:
In vivo assessment of antimicrobial activity of enterocin CRL35 and Enterococcus mundtii CRL35 in a murine model of pregnancy-associated Listeria monocytogenes infection.
Autor/es:
SAAVEDRA, L; SALVUCCI, E; HEBERT, M.E; HARO, C; VIGNOLO, G; SESMA, F.
Lugar:
Kosice
Reunión:
Conferencia; International Scientific Conference on Gastro-Intestinal Microbial Ecology; 2010
Institución organizadora:
Pavol Jozef afárik University in Koice, Faculty of Medicine
Resumen:
Listeria monocytogenes has been recognized
as a foodborne pathogen that can be acquired mainly by the consumption of
refrigerated and ready-to-eat products. Pregnant individuals are among the most
susceptible population for listeriosis where the consequences may result in
miscarriage and fetal death.
Enterococcus mundtii CRL35 produces
enterocin CRL35, a subclass IIa bacteriocin active against Listeria. Previous
studies demonstrated that combinations of enterocin CRL 35 with certain
antibiotics strongly increase their activity leading to marked reduction of
their doses. These results suggest a potential application of such combinations
in the medicine or pharmaceutical fields. As a first step in this direction we
set up a murine model of listeriosis to test the effectiveness of enterocin
CRL35 and its producer strain.
Methods: E.mundtii CRL35 was grown for 16 h
at 37ºC
in LAPTg broth and enterocin CRL35 was purified (PE) from this culture
supernatant by our standard lab procedure. A murine model of pregnancy
associated Listeria infection was achieved. Five to six week-old female BALB/c
mice were orally infected with L. monocytogenes FBUNT at day 14 and sacrificed
at day 17 of pregnancy. Mice were randomly divided in five groups that
received: a) L .monocytogenes FBUNT (5 x 109 CFU); b) L. monocytogenes FBUNT (5
x 109 CFU) plus a treatment of 65 µg of PE per animal every 12 h; c) E mundtii
CRL35 (2 x 109 CFU) and 5 h later L. monocytogenes FBUNT (5 x 109 CFU); d) PBS;
e) 65µg of PE every 12 h. Mice were anaesthetized and killed after blood
collection by cardiac puncture. Liver, spleen and fetus were aseptically taken,
homogenized and plated on Listeria selective agar (Oxoid) and Brain Heart
Infusion (BHI). Plates were incubated at 37ºC for 48 h. Viable counts were expressed as
log colony-forming units (CFU) per gram of organ. Changes in weight, food and
fluid intake as well as hematologic parameters were also analyzed. All animal
protocols were preapproved by the CERELA Animal Protection Committee and all
experiments complied with the current laws of Argentina
Results: The administration of a single
dose of L. monocytogenes FBUNT resulted in the translocation of the pathogen to
liver and spleen although it was not detected in fetus. Bacteriological
analysis demonstrated that the oral administration of enterocin CRL35 as well
as the bacteriocinogenic strain markedly reduced the CFU count of Listeria
cells in liver and spleen. However, preventive administration (3 days) of E.
mundtii CRL35 resulted in unspecific translocation of other members of gut
microbiota. None of the groups showed any remarkable changes of hematological
parameters, food and fluid intake.
Conclusion: These results evidenced that
enterocin CRL35 might be a good candidate for pharmacological or medical
applications. Although more studies need to be done in order to pursue this
issue.