Detection of abaI/abaR genes in Acinetobacter baumannii and phenotypically demonstrating of N-Acyl Homoserine Lactone

Background: Quorum sensing is a communication system among bacteria based on the actions of chemical signal molecules depending on the density of the cell population. These molecules are widely considered as effectors of the gene expression of several virulence factors. Aim: demonstrating for genes that have relation with quorum sensing system and to detect the long signal molecules of N-acyl Homoserine Lactone (AHLs) in Acinetobacter baumannii. Methods: The current study was conducted to detect of quorum sensing genes (abaI/ abaR) in our local isolates as well as standard strain A. baumannii 19606 by using Polymerase Chain Reaction technique (PCR). Soft Agar Assay used for detecting of (Long chains) N-Acyl Homoserine Lactone Production. Results: In 18 isolates of A. baumannii, the presence of the abaI/abaR genes were the appearance of the abaI gene in 16 (88.8%), while the abaR gene was present in 10(55.5%). Soft agar method was investigated to detect of long signal molecules N-Acyl Homoserine Lactone (AHLs) in A. baumannii by using Agrobacterium tumefaciens as biosensor strain, the results was that ten out of eighteen isolates were determined to be AHL-producing strains, and gave a positive result, which is the appearance of a blue halo around colonies indicating the production of signal molecules. Conclusion: abaI/abaR were distributed widely in local A. baumannii , N-acyl Homoserine Lactone can detected by Agrobacterium tumefaciens.