Related Experiment Video
Updated: Jan 22, 2026

Bile Salt-induced Biofilm Formation in Enteric Pathogens: Techniques for Identification and Quantification
Published on: May 6, 2018
Characterization of Salmonella resistance to bile during biofilm formation
Ming-Han Tsai1, Yi-Hua Liang2, Chyi-Liang Chen3
1Department of Pediatrics, Chang Gung Memorial Hospital, Keelung Branch, Keelung, Taiwan; Chang Gung University College of Medicine, Taoyuan, Taiwan; Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
Background:
Non-typhoid Salmonella infection may present as acute gastroenteritis or chronic infection, primarily in the bile-rich gallbladder. Biofilm formation is a mechanism of bile resistance in Salmonella. Our aim was to determine how Salmonella utilizes bile as a signal, and to study the relevance of the interaction between the PhoP-PhoQ two-component system and cyclic diguanosine monophosphate (c-di-GMP) signaling to biofilm formation.
Methods:
Two-dimensional (2-D) gel electrophoresis was used to identify genes required for Salmonella biofilm formation in bile. Quantitative real-time PCR (qRT-PCR) was used to clarify the role of the PhoP-PhoQ two-component system and its interaction with genes involved in the c-di-GMP network during biofilm formation.
Results:
Our result revealed that Salmonella mutants with incomplete outer membrane (△ompA), defective flagella (△flgE), or incomplete PhoP-PhoQ two-component system (△phoP), were unable to develop complete biofilms in the presence of bile. Moreover, PhoP-PhoQ two-component system-related Salmonella mutants (△phoP, △phoQ, △phoP△phoQ) had lower expression of c-di-GMP related genes (csgD, adrA) than the wild-type Salmonella strain had in the bile environment.
Conclusion:
Salmonella may sense and respond to bile through the PhoP-PhoQ two-component system during biofilm formation. Furthermore, the PhoP-PhoQ two-component system might activate regulators of the c-di-GMP signaling network.
Related Concept Videos
Bile
Bile is released when dietary fats enter...
Biofilms
Resistivity
Resistance
Resistance and Conductance
Various factors impact the resistance of a conductor. Spiraling in stranded conductors increases their...
Equivalent Resistance

