INLAIN   20354
INSTITUTO DE LACTOLOGIA INDUSTRIAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Antimicrobial spectrum of Bifidobacterium animalis subsp. lactis INL1 and the influence of drying on functionality.
Autor/es:
SOUZA, T.; ZACARIAS, M.F.; CARMONA, D.; VIEIRA, L.; NICOLI, J.; REINHEIMER, J.A.; VINDEROLA, G.
Reunión:
Congreso; XII Congreso Argentino de Microbiología.; 2010
Resumen:
Introduction: Bifidobacterium animalis
subsp. lactis INL1 is a strain
isolated from human breast milk with resistance to technological processes of
interest for the dairy industry such as freezing, freeze-drying, spray-drying
and mild heating (50°C).
The functional properties of this strain, to be considered as a probiotic
(immunomodulation capacity, antimicrobial activity, etc.), are under study. Recent
studies suggest that technological treatments like those described above could
modify cell functionality of probiotic bacteria without affecting cell
viability.
Aim: To study the in vitro antimicrobial
capacity of B. lactis INL1 against enteropathogenic
indicators and the in vivo effect of
freeze-drying and spray-drying on its immune properties, estimated as the
capacity to enhance s-IgA production in intestinal fluid and proliferation of
Küpffer cells in liver.
Materials and Methods: For the study of antimicrobial activity, the well-diffusion and
agar-spot assays were compared using the following pathogens: Salmonella enterica subsp. enterica serovar Typhimurium FUNED, Vibrio cholerae LEFM, Shigella sonnei ATCC 11060, Shigella flexneri LEFM, Enterococcus faecalis ATCC 19433, Listeria monocytogenes ATCC 15313, Escherichia coli ATCC 25922 and Clostridium perfringens type A ATCC
3624. Swiss NIH mice received, by daily gavage and for 10 consecutive days, 10%
skim milk (control group) or 108 CFU of B. animalis subsp. lactis
INL1 as fresh, spray-dried or freeze-dried cultures in 10% skim milk. Liver was
removed for Küpffer cells count by histological examination and small
intestinal fluid was used for determination of s-IgA contents by capture-ELISA.
Results: An antimicrobial activity against V. cholerae, S. flexneri
and E. coli was detected using the agar-spot
assay but not by well-diffusion assay. Only the oral administration of
bifidobacteria as fresh culture significantly increased (P < 0.05) the number of Küpffer cells (45.9±8.6 cel.+/100
hepatocytes) when compared to control mice (30.2±2.5 cel.+/100 hepatocytes). Administration
of bifidobacteria as fresh (59.9±16.7 pg/ml), freeze-dried (29.3±3.1 pg/ml) and
spray-dried (25.6±0.7 pg/ml) cultures significantly increased the concentration
of s-IgA in the intestinal fluid when compared to control mice (18.6±1.1 pg/ml).
Conclusions: In vitro antimicrobial
activity against some pathogenic bacteria was detected for the strain studied
only by the agar-spot assay. The reason why one methodology was effective
compared to the other one remains unknown but should be taken into account for
other studies. B. animalis subsp. lactis INL1 displays in vivo immunomodulatory properties,
being this capacity significantly modified by the technological treatments
applied to the strain. It was confirmed that plate counts may offer just a
partial view of cell functionality since technological treatments affected the
immunomodulating capacity of the strain without this fact being noticed by
enumeration of viable cells by plate counts.