Lactobacilli Antagonize the Growth, Motility, and Adherence of Brachyspira pilosicoli: a Potential Intervention against Avian Intestinal Spirochetosis

Abstract

ABSTRACTAvian intestinal spirochetosis (AIS) results from the colonization of the ceca and colorectum of poultry by pathogenicBrachyspiraspecies. The number of cases of AIS has increased since the 2006 European Union ban on the use of antibiotic growth promoters, which, together with emerging antimicrobial resistance inBrachyspira, has driven renewed interest in alternative intervention strategies. Probiotics have been reported as protecting livestock against infection with common enteric pathogens, and here we investigate which aspects of the biology ofBrachyspirathey antagonize in order to identify possible interventions against AIS. The cell-free supernatants (CFS) of twoLactobacillusstrains,Lactobacillus reuteriLM1 andLactobacillus salivariusLM2, suppressed the growth ofBrachyspira pilosicoliB2904 in a pH-dependent manner. Inin vitroadherence and invasion assays with HT29-16E three-dimensional (3D) cells and in a novel avian cecalin vitroorgan culture (IVOC) model, the adherence and invasion ofB. pilosicoliin epithelial cells were reduced significantly by the presence of lactobacilli (P< 0.001). In addition, live and heat-inactivated lactobacilli inhibited the motility ofB. pilosicoli, and electron microscopic observations indicated that contact between the lactobacilli andBrachyspirawas crucial in inhibiting both adherence and motility. These data suggest that motility is essential forB. pilosicolito adhere to and invade the gut epithelium and that any interference of motility may be a useful tool for the development of control strategies.