25º Congresso Brasileiro de Microbiologia

25º Congresso Brasileiro de Microbiologia

ResumoID:1498-1

Área: Patogenicidade Microbiana ( Divisão D )

ROLE OF THE INTESTINAL MICROBIOTA ON HOST SUSCEPTIBILITY TO SALMONELLA ENTERICA SEROVAR TYPHIMURIUM

Rosana Barreto Rocha Ferreira (UBC); Shannon Russell (UBC); Navkiran Gill (UBC); B. Brett Finlay (UBC)

Resumo

The intestinal microbiota is composed of hundreds of different species of bacteria, fungi and protozoa and outnumbers host cells by an order of magnitude. Its importance has been shown in numerous biological processes, such as nutrient acquisition, vitamin production, fat storage regulation and colonization resistance against bacterial species such as Salmonella Typhimurium. S. Typhimurium is one of the most prevalent causative agents of gastrointestinal disease. The main goal of this work was to analyze the importance of different members of the intestinal microbiota on host resistance to S. Typhimurium infections. For this purpose, low doses of the antibiotics, streptomycin, vancomycin, trimethoprim and metronidazole were administered to mice and susceptibility to S. Typhimurium infection was evaluated. These antibiotics were able to disrupt the microbiota composition of the intestine as seen by fluorescence in situ hybridization (FISH) and terminal restriction fragment length polymorphism (TRFLP), but did not significantly affect the total numbers of bacteria in the feces. Except for trimetropin, all antibiotic treatments caused increased susceptibility to infection. The development of enterocolitis was seen when streptomycin and vancomycin were used but no inflammation was observed with the use of metronidazole. Taken together these results highlight the importance of the microbiota as a barrier to bacterial infections. Furthermore, the fact that the total number of bacteria is not significantly changed with the use of different antibiotics even though the severity of the disease is affected, suggests that the resistance to Salmonella infection and inflammation may be influenced by specific members of the microbiota rather than simply by a general physical barrier to infection. Understanding which microbiota members are important to protect the host against infection may be useful for the development of therapeutic and preventive measures against Salmonella.

Palavras-chave: Salmonella, microbiota, antibiotics, enterocolitis

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