Study Of The Sterilization Effect Of Medical Ozone On The Body Fluid

Ozone is a chemical compound consisting of three oxygen atoms(O₃-triatomic oxygen),the pure gas has a soft sky-blue colour with pungent,acrid smell. Ozone is very instable in atmospheric,the life of the ozone molecule depends on the temperature,so that at 20℃the ozone concentration is halved within 40min.Medical grade ozone(Medical ozone) must be made from pure medical oxygen,its concentration could be well controlled.Medical ozone is actually a mixture of pure oxygen and pure ozone in the ratio of 0.05%to 5%of O₃ and 95%to 99.95%of O₂.Due to the instability of the O₃ molecule medical ozone must be prepared immediately before use("ozone" was mentioned below instead of"medical ozone").Among oxidant agents,ozone is the third strongest,after fluorine and persulfate.Because of its high oxidative power,it has sterilization effect on bacteria, HAV,and HIV with the ozone concentration of 20～80μg/ml in aqueous medium.There are 150 million people with chronic hepatitis B virus(HBV) and hepatitis C virus(HCV) infection in our country.Blood transmission is the main hepatitis transmission route.Unfortunately,safety problems of blood products such as transfusion-transmitted virus and bacteria infections have not been solved yet. Because of the virus residue in blood,hepatitis B recurrence may still happen after liver transplantation to the patients whose end-stage liver disease was caused by chronic HBV infection.Currently,the most effective drugs used for preventing hepatitis B recurrence after liver transplantation are hepatitis B immunoglobulin (HBIG) combined with Lamivudine,but it costs a lot.There is still no effective preventive methods of hepatitis C recurrence after liver transplantation.Among the major complications of cirrhosis,ascites seems to be the most frequent one.Patients with cirrhosis and ascites show a higher susceptibility to bacterial infections-mainly because of the inadequate defence mechanisms and bacterial translocation(BT).In these patients,the most frequent infectious complication that occurs(10%～25%of the cases),and at the same time the most severe one-is spontaneous bacterial peritonitis(SBP).SBP pathogenesis is considered to be the main consequence of bacterial translocation.More than 50% of the SBP episodes are produced by gram negative enteric bacilli-E.coli,followed by Staphylococcus aureus and Enterococcus faecalis.The efficiency of ascites concentration and reinfusion being enhanced after preconditioning ascites with disinfectant such as ozone is reasonable.As ozone has such strong sterilization effect on kinds of microorganism,we test the bactericidal effect of ozone on body fluids(plasma,ascites),to get parameters of the sterilization effect of ozone for treating with body fluid such as plasma and ascites.Partâ… Study of the sterilization effect of ozone on plasma1.Methods:Escherichia coli(ATCC25922) and Staphylococcus aureus(ATCC25923) suspended in physiologic saline were treated by medical ozone with different concentration treating for 5 min.The killing rate was calculated according to the bactericidal assay of quantitative suspension.The bacteria killing rate were also tested in plasma with 90μg/ml ozone treating for different time.Then different ozone treating time was choosed to test the sterilization effect of ozone with the concentration of 80μg/ml on different saline-plasma mixture.2.Results:2.1 Ozone even with lower concentration has great sterilization effect on physiologic saline;2.2 After treated with ozone of concentration of 90μg/ml for 20min,the killing rate to Escherichia coli and Staphylococcus aureus in whole plasma were only 50.35%and 43.58%respectively.2.3 The bactericidal rate of ozone of the concentration 80μg/ml to Escherichia coli and Staphylococcus aureus decreased from 100%to less than 50%with plasma concentration increased.Significant difference exists in mass among groups of different ozone treating time(F=30885.690,P=0.000) and different plasma concentration(3.3%,5.0%,10.0%,20.0%,50.0%,100.0%)(F=51420.241,P=0.000 when treating with Escherichia coli,and the same condition occurs when treating with Staphylococcus aureus(F=27441.387,P=0.000 and F=75088.996,P=0.000 ).3.Conclusions:Ozone had better sterilization effect in physiologic saline than in plasma,even 10%plasma in bacterial suspensions inhibit oxidation and protect bacteria.Ozone had better sterilization effect on Escherichia coli than on Staphylococcus aureus.The sterilization effect depended on the ozone concentration,the treatment time and plasma concentration of samples.Partâ…¡Study of the sterilization effect of ozone on intractable ascites of cirrhosis1.Methods:4 samples of ascetic fluid was collected for bacterial culture.Numbered the samples from different patients in order of ascitic fluid TP as NO.1～4.Sample A～C from one patient were numbered on the same principle.NO.4 and Sample C were the same one.Antibiotics were not used for a week before ascites collection. Escherichia coli(ATCC25922) and Staphylococcus aureus(AYCC25923) was added to the ascitic fluid which had cultured no colony available,then cultured in 37℃.The number of colonies was counted 24h later.Escherichia coli(ATCC25922) and Staphylococcus aureus(ATCC25923) was added to the 10 ml ascitic fluid and treated by medical ozone with the concentration of 80μg/ml treating for 5 min,10min and 20min respectively.The killing rate was calculated according to the bactericidal assay of quantitative suspension.Routine tests(total amount of proteins,cultures in blood-culture bottles) of ascitic fluid were performed in the same day.2.Results:Total proteins(TP) of 4 ascitic fluid samples(No.1～No.4) were 0.6,2.2,16.6,25.7g/L respectively.There were differences between 4 samples in the cultured colony counts:No.l＞No.2＞No.3＞No.4.Ozone of the concentration 80μg/ml had better sterilization effect on ascites than on plasma.Significant difference exists in mass among groups of different ozone treating time(F=28514.907,P=0.000) and different ascitic fluid samples(F=40499.603,P=0.000) when treating with Escherichia coli,and the same condition occurs when treating with Staphylococcus aureus(F=13066.314,P=0.000 and F=92525.40,P=0.000).The bactericidal rate of ozone to Escherichia coli and Staphylococcus aureus increased with the ozone treating time increased,it all reached to more than 70%when ozone treating time was 20min.The same tendency of bactericidal efficiency was displayed among different time condition:No.1＞No.2＞No.3＞No.4,while the TP tendency seems to be opposite. Total proteins(TP) of 3 ascitic fluid samples(Sample A～E) which collected from one patient were 14.6,22.1,25.7 g/L respectively.Significant difference exists in mass among groups of different ozone treating time(F=38534.299, P=0.000) and different ascitic fluid samples(F=395.821,P=0.000) when treating with Escherichia coli,and the same condition occurs when treating with Staphylococcus aureus(F=10800.111,P=0.000 and F=520.915,P=0.000).The bactericidal rate of ozone to Escherichia coli and Staphylococcus aureus increased with the ozone treating time increased.The same tendency of bactericidal efficiency was displayed among different time condition:Sample A＞B＞C,while the TP tendency seems to be opposite.3.Conclusions:3.1 The ascitic fluid samples with lower TP show a higher susceptibility to bacterial infections(more colony counts).3.2 Ozone had better sterilization effect on ascites than on plasma.The sterilization effect differed in different ascitic fluid samples.The sterilization effect depended on ozone treating time and TP of ascitic fluid.The ascitic fluid with lower TP show a better sterilization effect.