Exposure to norepinephrine enhances Brachyspira pilosicoli growth, attraction to mucin and attachment to Caco-2 cells

R. Naresh, D. J. Hampson
2010 Microbiology  
Naresh, R. and Hampson, D.J. (2011) Exposure to norepinephrine enhances Brachyspira pilosicoli growth, attraction to mucin and attachment to Caco-2 cells. Microbiology, 157 (2). pp. 543-547. Summary 22 Brachyspira pilosicoli is an anaerobic intestinal spirochaete that colonises the large 23 intestine of a variety of species of birds and mammals, including human beings. 24 Colonisation may result in a mild colitis and diarrhoea in a condition known as 25 "intestinal spirochaetosis". The
more » ... osis". The catecholamine norepinephrine (NE), which is known to 26 influence the behaviour of many bacterial species, may be present in the colon. The 27 purpose of the current study was to determine whether exposure of B. pilosicoli to NE 28 would influence its in vitro behaviour in assays that may reflect in vivo colonisation 29 potential. B. pilosicoli strain 95/1000 was used in all the assays. Addition of NE at a 30 concentration of 0.05 mM to B. pilosicoli growing in anaerobic broth significantly 31 increased spirochaete numbers after four days incubation. The effect of higher 32 concentrations of NE was not significant. Exposure to 0.05 mM NE, but not to higher 33 concentrations, also resulted in significantly more spirochaete cells entering capillary 34 tubes containing 4% porcine gastric mucin than occurred with untreated cultures. 35 When NE was added to chemotaxis buffer in capillary tubes significantly more 36 spirochaetes were attracted to the buffer containing NE concentrations of 0.1, 0.5 and 37 1.0 mM than to 0.05 mM, or when no NE was added. Exposure of B. pilosicoli cultures 38 to 0.05 mM NE prior to incubation with Caco-2 monolayers resulted in more 39 attachment to the monolayer than occurred with non-exposed cultures. These results 40 show that at higher concentrations NE acts as a chemoattractant for B. pilosicoli, and at 41 0.05 mM it increases the spirochaete's growth rate, attraction to mucin, and its rate of 42 attachment to cultured enterocytes. These activities are likely to enhance the ability of 43 B. pilosicoli to colonise, and may be induced by conditions that increase NE 44 concentrations in the intestinal tract, such as the stresses associated with crowding. 45 46
doi:10.1099/mic.0.044594-0 pmid:21051488 fatcat:ykth5mkyrvcg5eo5pebdhga76a