The Influence of Staphylococcus aureus on Gut Microbial Ecology in an In Vitro Continuous Culture Human Colonic Model System

Abstract

An anaerobic three-stage continuous culture model of the human colon (gut model), which represent different anatomical areas of the large intestine, was used to study the effect of S. aureus infection of the gut on the resident faecal microbiota. Studies on the development of the microbiota in the three vessels were performed and bacteria identified by culture independent fluorescence in situ hybridization (FISH). Furtheremore, short chain fatty acids (SCFA), as principal end products of gut bacterial metabolism, were measured along with a quantitative assessment of the predominant microbiota. During steady state conditions, numbers of S. aureus cells stabilised until they were washed out, but populations of indigenous bacteria were transiently altered; thus S. aureus was able to compromise colonisation resistance by the colonic microbiota. Furthermore, the concentration of butyric acid in the vessel representing the proximal colon was significantly decreased by infection. Thus infection by S. aureus appears to be able to alter the overall structure of the human colonic microbiota and the microbial metabolic profiles. This work provides an initial in vitro model to analyse interactions with pathogens.

Enterohemorrhagic Escherichia coli O157:H7 Survival in an In Vitro Model of the Human Large Intestine and Interactions with Probiotic Yeasts and Resident Microbiota

“…The major phyla of gut microbiota and their main members (41,42) were counted throughout fermentations in the ARCOL (Table 4). During the stabilization phase (phase A), their concentrations were similar to those described in humans (43,44) or in other in vitro models of the human gut (45,46).…”

Staphylococcus aureus MnhF Mediates Cholate Efflux and Facilitates Survival under Human Colonic Conditions

“…The three-stage continuous-culture model of the human colon was described previously (16,30). The experiment was carried out in triplicate, using fecal samples from three different volunteers.…”

“…In vivo studies of colonic bacteria are hampered by the lack of suitable animal models, as these models do not correctly simulate the microbiota and physicochemical conditions of the human colon (36). We have previously used this in vitro model to study survival of S. aureus and the impact of infection on the host's intestinal microflora (16).…”

“…Bile is a digestive secretion that plays an essential role in the emulsification and solubilization of lipids. We have previously demonstrated the survival of S. aureus in a human colonic model fed with physiological levels of bile (16). Resistance to bile salts has been demonstrated to be important for the intestinal survival of several enteric pathogens, but for S. aureus, such an understanding is lacking.…”

Inactivation of Staphylococcus aureus by high pressure processing: An overview

“…aureus is an exceptionally well adapted opportunistic pathogen that can survive under different conditions, with no particular nutritional or environmental requirements (Brown, Cornforth, & Mideo, 2012;Feng et al, 2008;Normanno et al, 2005). This microorganism is able to withstand several months on items and surfaces and is capable to cause a large range of diseases in humans and animals (Sannasiddappa, Costabile, Gibson, & Clarke, 2011;Sigler & Hensley, 2013;Wertheim et al, 2005).…”