Selection of a candidate probiotic strain of Pediococcus pentosaceus from the faecal microbiota of horses by in vitro testing and health claims in a mouse model of Salmonella infection.
OBJECTIVE
The aim of this study was to verify the suitable use of candidate 'probiotics' selected by in vitro tests and the importance of in vivo assays to nominate micro-organisms as probiotics and alternative prophylactic treatments for Salmonella Typhimurium infection.


RESULTS
Thirty-three lactic acid bacteria (LAB) isolated from foal's faeces were assessed based on the main desirable functional in vitro criteria. Based on these results, Pediococcus pentosaceus strain 40 was chosen to evaluate its putative probiotic features in a mouse model of Salmonella infection. Daily intragastric doses of Ped. pentosaceus 40 for 10 days before and 10 days after Salmonella challenge (106CFU of Salm. Typhimurium per mouse) led to a significant aggravation in mouse health by increasing weight loss, worsening clinical symptoms and anticipating the time and the number of deaths by Salmonella. Pediococcus pentosaceus modulated cell-mediated immune responses by up-regulation of the gene expression of the proinflammatory cytokines IFN-γ and TNF-α in the small intestine.


CONCLUSIONS
The usual criteria were used for in vitro screening of a large number of LAB for desirable probiotic functional properties. However, the best candidate probiotic strain identified, Ped. pentosaceus #40, aggravated the experimental disease in mice.


CONCLUSIONS
These findings emphasize the need for prophylactic or therapeutic effectiveness to be demonstrated in in vivo models to make precise health claims.
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Campus Pampulha, Belo Horizonte, MG, Brazil.
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BC
Silva
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Campus Pampulha, Belo Horizonte, MG, Brazil.
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http://orcid.org/0000-0001-6157-8197
SH
Sandes
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Campus Pampulha, Belo Horizonte, MG, Brazil.
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LB
Alvim
Laboratório de Biologia Molecular de Microrganismos do Núcleo de Biologia Parasitária, Centro Universitário do Maranhão (UniCEUMA), São Luís, MA, Brazil.
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MR
Bomfim
Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Campus Pampulha, Belo Horizonte, MG, Brazil.
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JR
Nicoli
Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Campus Pampulha, Belo Horizonte, MG, Brazil.
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E
Neumann
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Campus Pampulha, Belo Horizonte, MG, Brazil.
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AC
Nunes
D000818:Animals; D016207:Cytokines / Q000235:genetics / Q000276:immunology; D004195:Disease Models, Animal; D005243:Feces / Q000382:microbiology*; D005260:Female; D006736:Horses; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D000070006:Pediococcus pentosaceus / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D019936:Probiotics / Q000008:administration & dosage*; D012475:Salmonella / Q000502:physiology; D012480:Salmonella Infections / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
D016207:Cytokines; D014409:Tumor Necrosis Factor-alpha

Salmonella
; immunology; intestinal microbiology; lactic acid bacteria; probiotics