In vitro phase variation studies of Salmonella Gallinarum in biofilm formation

摘要

Transmission electron microscopy studies were carried out to capture the sequential steps involved in the formation of biofilms in vitro by Salmonella Gallinarum. Bentonite clay provided in the growth medium acted as a good inert surface for bacterial attachment and biofilm formation at submaximal rates of nutrients. In the initial stages, bacteria started attaching to the surface of bentonite clay and started expressing extracellular polysaccharides (EPS) and curli, which in turn led to repression of flagella and pili. In the later stages, microcolonies were formed leading to maturation of biofilms by overexpression of EPS. The attempt to mimic in vivo biofilm formation in vitro revealed the process of phase variation.