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The Scientific World Journal
Volume 2014 (2014), Article ID 153956, 5 pages
http://dx.doi.org/10.1155/2014/153956
Research Article

Effect of Simulated Gastrointestinal Conditions on Biofilm Formation by Salmonella 1,4,[5],12:i:-

1Interdisciplinary Centre of Research in Animal Health (CIISA), Faculdade de Medicina Veterinária da Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
2ISPA - Instituto Universitário das Ciências Psicológicas, Sociais e da Vida, Rua Jardim do Tabaco 34, 1149-041 Lisboa, Portugal
3National Reference Laboratory of Gastrointestinal Infections, Centro Nacional de Salmonella, National Health Institute Doutor Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisboa, Portugal

Received 12 March 2014; Revised 25 May 2014; Accepted 6 June 2014; Published 30 June 2014

Academic Editor: Paul Cos

Copyright © 2014 R. Seixas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Salmonella Typhimurium 1,4,[5],12:i:- is a major serovar responsible for human salmonellosis whose biofilm-forming ability, influenced by environmental conditions like those found in the gastrointestinal tract, is one of the main contributing factors to its ability to persist in the host and thus one of the main causes of chronic relapsing infections. Most studies to evaluate biofilm formation are performed in microtiter assays using standard media. However, no reports are available on the ability of this serovar to produce biofilm under in vitro simulated gastrointestinal conditions which better correlate with the environment found in the gastrointestinal tract. To address this, a modified biofilm assay simulating intestinal fluid was conceived to assess the biofilm formation of 133 Salmonella Typhimurium 1,4,[5],12:i:- isolates with and without agitation and at three different time points (24 h, 48 h, and 72 h). The results were then compared to the existing microtiter method using conventional biofilm growth medium (Mueller Hinton Broth). Statistical analysis revealed significant differences in the results obtained between the three protocols used. The simulated human intestinal environment impaired biofilm production demonstrating that conditions like pH, agitation or the presence of enzymes can influence biofilm production. Therefore, results from in vitro simulation of in vivo conditions may contribute to unravelling factors relating to biofilm formation and persistence in the context of the human host.