A Study Of Automatic Mechanical Cleaning And Disinfection Of Gastroscope Contaminated With Hepatitis B Viruses

Background:Hepatitis B Virus (HBV) infection is a major public health problem affecting millions of people worldwide.Following acute HBV infection, 5%-10% of the adult patients will develop persistent infection that may lead to chronic hepatitis, cirrhosis, and hepatocellular carcinoma.HBV infection is one of important factors affecting health.HBV is spread through blood ,urine, and other body fluid.people contacting it are likely to get HBV infection. Recently, people pay more attention to hospital acquired infection. Epidemiological studies suggest that the incidence of infection after endoscopic procedures is only one in 1.8 million. Endoscopic instruments are contaminated with microorganisms during use.High level disinfection of gastrointestinal endoscopes is essential prevent microbal transmission. There are reports of iatrogenic infection caused by improperly disinfected endoscopic equipment.To select convenient,practical and reliable cleaning and disinfection method is of great importance. Grutaraldehyde solutions are the most widely used liquid disinfectants in the United States for reprocessing endoscopic2002equipment.After each procedure, thorough cleaning of adherent contaminant on the surface of endoscope body as well as in the channels is essential. With three-step method disinfection of the endoscope can be satisfactorily achieved, but manual operation,if applied,should be standardized and sufficient. Automatic cleaning and disinfection can save man power and prevent artefact affecting disinfection outcome.Objective: To investigate the possibility of Hepatitis B Viruses (HBV) contaminating gastroscope and to determine the effectiveness of automatic mechanical cleaning and disinfection method and the shortest disinfectant time of automatic mechanical disinfection,and traditional manual cleaning and disinfection method was to be comparered.Methods: Through the imitative experiment on disinfection of gastroscope contaminated with hepatitis B surface antigen, 2ug/ml HBsAg was artificially spreaded on the body of gastroscope, biopsy clamp and biopsy hole. The gastroscope was disinfected by manule method and mechanical one for Imin, 3min, 5min respectively. HBsAg in the samples collected before and after disinfection were tested by immunoassay. Gastroscopes used for patients with positive serum HBsAg were disinfected by automatic disinfection machine, samples were collected before and after treatment. Immunoassay was used to test HBsAg,PCR(polymerase chain reaction) techniques were used to test HBV-DNA.Results: HBsAg can be detected before disinfection ,and can not be detected after manual disinfection or mechanical one for 3min. or 5min. After mechanical disinfection for Imin, HBsAg can be detected in the samples collected from the body of gastroscope but can not be detected from biopsy2002clamp and biopsy hole. After disinfection, 15/50 samples with positive HBsAg became negative, 12/50 samples with positive HBV DNA became negative ,too.Conclusion: Gastroscopy inspection is probably one of the ways spread HBV, mechanical disinfection can effectively remove HBsAg and HBV DNA,and can promote the frequency of utilizing gastroscopy,and can also save man power and prevent artefact affecting disinfection outcome .