Research In Clinical And Assayin Vitro About The Effect On Growth Of Pathogenic Bacterium And Expression Of Virulence Factor By Alteration Of Urine PH From UTI

Background and Objectives:The urinary tract infection(UTI)is commonly encountered and frequently-occurring disease. Maskell[1] estimated that about 50 percent women have encountered UTI in the whole life.Data means of mass screening in China showed that the incidence rate of UTI in women was 2.05 percent.In spite of the rapid research and development on antibiotics and replacing the old with new varieties continuely,the incidence rate of UTI has been increased instead of falling down,and the treatment in clinical has been faced with new challenges unceasingly.At the present,clinician were like to use antibiotics with much larger dose,much more varities and much longer time of therapy,which has not only made therapy-cost much higher,but also produced much more drug resistant strains endlessly,and an unceasing increase of the infection by nonpathogenic bacterium in the past and the therapeutic effect has fallen off.Under normal circumstances can human body have the consummate defense mechanism.Effective urination and evacuating of bladdery are very important to prevent UTI[2][3]. The mucoprotein on the surface of the urinary tract is an important barrier for preventing the bacterial infections. The invading of pathogenic bacteria and the urinary tract can cause inflammatory reaction in local urinary tract and generate a great quantity of cytokine, which can prohibit the extension and the progress of the inflammatory. In addition to this, the first barrier for human body to UTI, which is considered the top-drawer barrier can due to the bacteria suppress ability of the normal urine itself. Researches show that normal urine contain many antisepsis factors, such as polyamine ,high concentration urea, urine pH, hyperosmosis, salt, organic acids and so on, even the diluent urine could have the inhibition ability to bacterials, especially the urine with low pH.Along with the changes of internal and external environment, the distributions of pathogenic bacterium at different periods or from different areas were distribution, the urine pH infected by which could have changed dissimilarly.Studies also show that the most pathogenic bacterium can cause UTI is the uropathogenic escherichia coli (UPEC),the prerequisite of which is capable to colonization in the urinary tract.The pilus of UPEC produces adhesion,which can bind with the adhesion acceptor on the surface of uroepithelium.0n the basis of Sensitivity and Specificity of acceptor to the adhesions,pili are distinguished with P- pilus,Ⅰ-pilus etc.UPEC also secrete varied virulence facto,such asα- hemolysin (α-hly),the most capital virulence factor,can effect cytotoxic to the eukaryocytes.Bacterial pathogenicity degree is correlated intimately with the expression degree of virulence factors.Latest researches prompt that the pH can affect the expression of virulence factors[4] [5].we collected and analyzed the data of pathogens and the infected urine pH from urinary samples of patients with UTI in our hospital from Jan,2007 to Nov,2009,and then in vitro assay we evaluated the growth and the expression of virulence factors of UPEC J96 in urine with distinct pH.By investigating the distribution of bacterial and the corresponding range of urine pH,likewise identifying the inhibitive effect on the UPEC by urine pH.During the prevention and cure of UTI in clinical,according to individual pathogenic bacterium and the corresponding range of urine pH we can affect the external environment by regulating the urine pH,in order to reach a better treatment effectively with a less dose and a less phyletic antibiotics.Methods:Collecting the data of 606 strains of pathogens and the infected urine pH from urinary samples of patients with UTI in our hospital were obtained,the distribution of pathogens was described,and the pathogens was divided into 3 groups according to the genus,the urine pH of which was analyzed by the statistics method.In vitro, the experimental model of urine medium was established and the effect of urine pH on the growth and the expression of virulence factors of UPEC J96 was observed. All the UPEC J96 were divided and inoculated into controllable group, experimental group randomly.The controllable groups were LB medium in pH7.0,the experimental groups were urine medium in 10 kinds of different pHs.We drew the Linearity at logarithmic phase by optical density of D600nm.Collect the protein of bacterium at the stationary phase.Evaluate and assay the expression of papC, fimH and hlyA of UPEC J96 from every group by western blot and optical densitometric methods.All works were repeated for 3 times. All datas were x±S from datas of the 3 times. Main results and conclusions:1. Among 606 strains from UTI, the group of escherichia rated the top one with 186 strains(30.7%) and the infected urine pH by escherichia distribute from 6.21 to 6.33 intensively;152 strains of candida were detected(25.1%), and the infected urine pH by candida distribute from5.81 to 5.95;86 strains of enterococcus were detected (14.2%), and the infected urine pH by enterococcus distribute from 6.10 to 6.28. By contrasting the infected urine pH of these three groups, we found the urine pH infected by candida was metaacid significantly(P<0.05).2. The urine pH from UTI were changed and the urine pH infected by different pathogens are dissimilar,which suggest it should reach the better treatment effectiveness with the less dose and the less phyletic antibiotics for bacteriostasis effect by regulating the urine pH.3. The growth of UPEC J96 in experiment groups(pH4.5,5.5,9) were significantly different to the experiment group pH7 (p<0.01).The expression of papC,fimH and hlyA in groups(pH4.5,5) was inhibited comparing with group(pH6.2) (P<0.01).4. UPEC J96 can grow and express the virulence factors in urine pH(6.0~6.5) just as well as in the control group,which prove that UPEC is capable to grow and express the virulence factors distinguished from others pathogenic bacterium.It is this characteristics cause the high disease rate of UTI by UPEC.5. Acidifying urine to pH<5 can inhibite the growth and the expression of virulence factors of UPEC J96.We believe depressing the urine pH could accomplish a favourable bacteriostasis effect by assisting the antibiotics. In clinical therapy chosing the optimal antibiotics not only according to pathogenic bacterium,but the urine pH after the regulation will avoid the the large dose treatment model without direction,and help us to accomplish the better treatment effectiveness with the less dose and the less phyletic antibiotics.