Research in Medicine

Introduction: Bacteria communicate with each other by using molecular chemical signal, which are called autoinducer. By the increase of concentration of these signals, which is the result of increase cellular density, they coordinate gene expression in a microbial community. This process is called Quorum sensing. Considering the importance of urine tract infections prominent role of Quorum sensing and external signals in regulation of bacteria gene expression. In the present paper these concepts were studied: luxS, and rsbA genes’ band in Proteus mirabilis isolated from urinary tract infections and the effect of miristic acid as an external signal in regulation of gene expression.
Materials & Methods: In this study, 100 urine samples were collected. 10 Proteus mirabilis were isolated from these samples by standard bacteriologic methods. Subsequently, by the extraction of genome, the presence of luxS & rsbA gene bands were studied in 10 P. mirabilis. At the end, the effect of miristic acid on the swarming and the biofilm formation ability of the P. mirabilis is assessed.
Result: In 100 urine sample studied, 10 Proteus mirabilis (10%) were isolated. 70% studied P. mirabilis, contained luxS & rsbA gene bands. Miristic acid decreased the swarming of P. mirabilis in the concentration of 40 to 80 µl/100 ml of LB culture and the ability of P. mirabilis in the biofilm formation in all concentrations added to LB culture increased.
Discussion & Conclusion: The results obtained from the presence study indicate the presence of luxS and rsbA gene bands in most of P. mirabilis isolated from urinary tract infections, which demonstrate the presence of Quorum sensing regulatory systems in these bacteria. Also, the effect of miristic acid on the swarming and the biofilm formation ability of P. mirabilis containing rsbA gene, shows that respondent regulatory systems to external signals presents in the bacterium. Therefore, by understanding these regulatory & communicatory systems, we can hope to infections control & new drug development.