Which of following is false regarding H. pylori:
Ans. (a) With chronic infection urease breath test becomes negative Urease breath test is most consistently accurate test for diagnosis of H. pylori. It becomes negative only after treatment and is used to assess outcome of treatment. Rmember:- Most specific test is microbiologic culture of specimen obtaining by upper GI endoscopic biopsy. Major virulence factor of H. pylori are vacuolating cytotoxin (VaCA) and group of genes called CagPal. Urea breath test, stool antigen test, and biopsy based tests can all be used to assess the success of treatment DIAGNOSIS OF H. PYLORI Test Advantages Disadvantages Invasive (based on endoscopic biopsy) Biopsy urease test Quick, simple Not fully sensitive before 24h Histology May give additional histologic information Sensitivity dependent on experience & use of special stains Culture Permits determination of antibiotic susceptibility Sensitivity dependent on experience Noninvasive Serology Inexpensive and convenient Cannot be used for early follow-up 13C or 14Curea breath test Inexpensive and simpler than endoscopy; useful follow-up after treatment Radiation exposure in 14Ctest for Stool antigen test Inexpensive & convenient; useful for follow-up after treatment; may be useful in children New test; appears less accurate than urea breath test
With chronic infection urease breath test become negative
H. pylori infection remains lifelong if untreated
Endoscopy is diagnostic
Toxigenic strains usually cause ulcer