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Protective effect of Lactobacillus sakei 2a against experimental challenge with Listeria monocytogenes in gnotobiotic mice
Author(s) -
Bambirra F.H.S.,
Lima K.G.C.,
Franco B.D.G.M.,
Cara D.C.,
Nardi R.M.D.,
Barbosa F.H.F.,
Nicoli J.R.
Publication year - 2007
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.2007.02250.x
Subject(s) - lactobacillus sakei , listeria monocytogenes , biology , microbiology and biotechnology , pathogen , virulence , lactobacillus , inoculation , bacteria , colony forming unit , starter , food science , fermentation , immunology , biochemistry , genetics , gene
Aim: Lactobacillus sakei 2a isolated from sausage and presenting an in vitro antagonistic activity against Listeria monocytogenes Scott A was tested for a protective effect in mice experimentally challenged with the enterobacteria. Methods and Results: In the experimental group, germ‐free mice ( n = 24) were inoculated intragastrically with 0·1 ml of a suspension containing 10 8 colony forming units (CFU) of Lact. sakei and 4 days later the animals were challenged intragastrically with 0·1 ml of a suspension containing 10 8 CFU of L. monocytogenes . Control group ( n = 24) was only inoculated with the bacterial pathogen. Faecal counts showed that L. monocytogenes reached similar population levels (10 9 CFU g −1 of contents) in both the groups. Animals in the control group showed lower ( P = 0·0004) survival frequency (58·3%) when compared with the experimental one (100%). Anatomopathological examination confirmed the mortality data. Conclusions: Lactobacillus sakei 2a can survive in the mammal digestive tract where showed a protective effect against L. monocytogenes . This phenomenon was not due to an antagonistic activity. Significance and Impact of the Study: Use of Lact. sakei 2a as a meat starter could inhibit not only L. monocytogenes growth in the fermented product but also pathogen virulence in the gastrointestinal tract.