幽门螺杆菌Hpylori+2课件.ppt

* * * * * * * * * * * * * * Author: Misiewicz G, Harris A Topic: Lecture Notes on Helicobacter pylori Source: Life Science Communications In developed countries re-infection after successful eradication is very uncommon; probably no more than 0.5 to 1.5% each year. Re-infection may be higher in children due to risk factors associated with this age group, such as lower standards of hygiene and close physical proximity. Socio-economic conditions are of the utmost importance in determining the prevalence of H. pylori infection. In developing countries where family sizes are large, standards of hygiene are low and overcrowding is common-place, the risk of re-infection with H. pylori may be higher than that reported from the industrialised nations, and may be as high as 30% each year. * * a. 数据来自Helicobacter pylori Antimicrobial Resistance Monitoring Program (HARP) * * * * * * * * * * * * * * * * Author: Misiewicz G, Harris A Topic: Lecture Notes on Helicobacter pylori Source: Life Science Communications Urea breath tests (UBTs) using 13C(non-radioactive) or 14C (radioactive isotope) are easy to perform, safe, highly sensitive (95%) and specific (100%). H. pylori produces abundant amounts of urease, which hydrolyses the labelled urea into labelled carbon dioxide (13 or 14CO2), which is excreted by the lungs. * Author: Misiewicz G, Harris A Topic: Lecture Notes on Helicobacter pylori Source: Life Science Communications The UBT involves collecting a breath sample before and 30 minutes after drinking a 13 or14C-labelled urea solution. Overall performance of the two UBTs is similar. The main difference between them is that 14C-UBT is radioactive and may therefore be used only in units with a medical physics or a fully equipped research department. The amount of radiation exposure in the 14C-UBT is negligible - about 10 tests give the same radiation dose as a chest radiograph - but it should still be avoided in pregnant women and children. 13C-U