Abstract: ［Abstract］］〓Objective〖HTSS〗〓To study the unique expression of the quorum sensing in the bacteria biofilm formation.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓We selected multidrug resistant Acinetobacter baumannii strains. Then we compared the two genomes in the rapid growth phase and biofilm state.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓In the same cell, the expressions of genes in the rapid growth phase and biofilm stage were different. The most significant factors in the expression of genes were the outer membrane proteins and the regulation of intracellular pathways. In the biofilm state, these regulators played a crucial role in the formation and maintains. Among them, the quorum sensing was one of the most important regulatory factors. It was significantly increased in the biofilm state.
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓The formation of bacteria biofilm could cause the long term survival of Acinetobacter baumannii. In the biofilm, the bacterial strain was continuously protected, resulting in increased resistance to the strain and repeated chronic infection in the hospital. The formation and morphology of the biofilm were relied on the regulation of quorum sensing. It may be involved in the regulation of biological behavior and contact among colonies in biofilms, so that the biofilm can be maintained as a whole.

Key words: Acinetobacter baumannii, drug resistance, multiple, bioflim formation