Ali Asgari - MS.c of Medical Microbiology, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran
RamezanAli Ataee - Professor of Department of Medical Microbiology, Faculty of Medicine, and Applied Microbiology Research Center, System Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
Ali Mehrabi Tavana - Professor of Medical Microbiology, Faculty of Medicine and Health Management Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
Reza Mirnejad - Professor of Medical Microbiology, Applied Microbiology Research Center, System Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
Mahdi Ghorbanalizdgan - Assistant professor of Medical Microbiology, Faculty of Medicine, and Applied Microbiology Research Center, System Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran

Background and Objective: The major pneumococcal pathogenesis factor is the capsular polysaccharide. the production of polysaccharide is regulated by cpsB and cpsD genes. Thus, every agent that induce or inhibition of expression of these genes probably increased pathogenesis of bacteria, intracellular survival and vis versa. The aim of this study was to assay the effect of Xylitol on Streptococcus pneumoniae cpsB, cpsD, psaA and aroE genes expression by Real Time RT-PCR. Materials and Methods: During ۲۰۱۹ in Baqiyatallah university laboratories, ۲۰ clinical isolates and a reference strain Streptococcus pneumoniae (ATCC ۶۳۰۵) were studied. To assay the effect of Xylitol and fructose، different concentration of these sugars were exposed to BHI Broth media. Thereafter, the bacterial suspension was added to ۵% Xylitol, ۵%Xylitol + ۵% fructose and control medium for ۳hours. RNA was extracted and cDNA synthesis was carried out. Then, the cpsB, cpsD and psaA genes expression levels were measured. Results: The mean of cpsB gene expression ratio in presence of the % ۵ Xylitol treated media compared with those in the control media and % ۵ Xylitol + ۵% fructose were ۰.۰۲۲ and ۰.۰۲۷ respectively. The means of the cpsD and psaA genes expression ratio in the % ۵ Xylitol treated media compared with those in the control media and % ۵ Xylitol + ۵% fructose were ۱.۶۵۹ and ۰.۰۵۶, and ۰.۶۳۳ and ۳.۲۹۴ respectively. Conclusion: Our finding revealed that, the ۵% Xylitol inhibit the cpsB gene expression properly. Therefore, it is possible to use of Xylitol for reductive on cpsB gene expression and superficial pneumococcal infections control.

Streptococcus pneumoniae, Xylitol, expression, cpsB, cpsD, psaA, aroE, RT Real- Time PCR, استرپتوکوکوس پنومونیه, گزایلیتول, بیان, cpsB, cpsD, psaA و aroE و RT Real- Time PCR