Case Study 67 Pathogenic Bacteriology 2009

1. Case Study 67Pathogenic Bacteriology2009 Rochelle Songco Omar Ahmed Hank Hsieh

2. Case Summary • Patient: 60 year old female with a past history of gastric ulcer • Symptoms of dyspepsia – pressure in the upper abdominal area that radiated to chest and neck • Upper GI series showed radiologic findings of thickened fold within the stomach • Outpatient esophagogastroduodenoscopy (EGD) was performed • Biopsy of antral part of the stomach was consistent with moderate gastritis. • No tumor was seen • 3+ to 4+ of bacterial organism was found

3. Case Summary Gastric biopsy photomicrograph from J Natl Med Assoc. 2007 January; 99(1): 31–34.

4. Key Information Pointing to Diagnosis • Presence of bacterial organism • Evidence of moderate gastritis visualized in biopsy • Past medical history of gastric ulcer • Symptoms of dyspepsia and abdominal pain

5. The Diagnosis for Case 67 • Disease is chronic gastritis • The causative organism is Helicobacter pylori • Confirmed by histopathologic examination of biopsy specimen

6. Classification,Gram Stain Results, and Microscopic Appearance of H. pylori • Gram negative • Small, curved bacilli • Multiple unipolar flagella • Microaerophilic • Similar to Campylobacter except for its ability to produce urease

7. Diseases and Pathogenesis of Disease Caused by H. pylori • Diseases • Chronic, active gastritis • Peptic ulcers • Symptoms are epigastric pain, nausea, vomiting, and anorexia • Risk factor for gastric cancer and lymphoma • Pathogenesis of disease • Urease - enables the survival of H. pylori in a low pH environment of the stomach lumen • Degrades urea to ammonia and carbon dioxide. Ammonia is alkaline and neutralizes the acid fluid in the stomach • Flagella – allows penetration through viscous mucous layer where conditions for growth are better

8. Pathogenesis of Disease Caused by H. pylori • CagA – syringe-like structure that injects itself into host epithelial cells • Activates signal transduction pathways and cell growth • Strains containing CagA have a higher inflammatory response and higher risk for peptic ulcer and gastric cancer • Vacuolating cytotoxin (VacA) – causes membrane channel formation, cell function interference, and apoptosis • Neutrophil-activating protein (NAP) – stimulates production of oxygen radicals from neutrophils which damage cells • Adhesions and outer membrane proteins – BabA and HpaA • LPS – thought to contribute to immune invasion by antigenic variation • Collagenase/Mucinase- causes damage to gastric epithelium by degrading mucous components and exposing cells to gastric acid

9. Diseases and Pathogenesis of Disease Caused by H. pylori • Epidemiology • Seems to have spread from East Africa about 58,000 years ago • Humans are principal reservoir and exact mechanisms of transmission are not really known • New infections are thought to occur from direct human-to-human transmission, via either an oral-oral or fecal-oral route or both • About 50% of the world’s population is infected • Prevalence is higher in developing countries, in older age groups, and in lower socioeconomic areas

10. Biopsy – invasive Culture biopsy sample on CampBAP or Skirrows media for up to 5 days or test for urease Urea breath test – non-invasive 14C ingested orally Breath samples tested for CO2 over 2 hours Rapid stool antigen test Serological tests – better for epidemiological studies ELISA FlexSure HP-solid phase immunchromatographic test Antibody tests for IgG in saliva specimens Diagnosis/Isolation/Identification/ of H. pylori

11. Therapy, Prevention and Prognosis of Patient Infected with H. pylori • Therapy • Triple or quadruple therapy consisting of two or three antimicrobials plus a bismuth or a proton pump inhibitor • Antibiotics used are tetracycline, amoxicillin, clarithromycin, and imidazoles • Prevention • Vaccines are being developed in animal models • Probiotics may prevent infection • Reduction of risk factors such as poor socioeconomic status, living conditions, and hygiene

12. Therapy, Prevention and Prognosis of Patient Infected with H. pylori • Prognosis • Over 80% eradication with drug therapy • Decreased rates in gastric cancer and lymphoma • Decreased H. pylori is associated with an increased risk for esophageal adenocarcinoma

13. Primary Research Article Contributing to the Understanding of the Disease caused by H. pylori • Hasan Umit, et al, 2008, The Relationship Between Virulence Factors of Helicobacter pylori and Severity of Gastritis in Infected Patients, Digestive Diseases and Sciences , 54(1): 103-110. • 57 dyspeptic patients infected with H. pylori underwent gastric endoscopy • Biopsy specimens were cultured under microaerophilic conditions with special media containing horse serum, antibiotics, and polyvitex • H. pylori were identified and harvested for DNA extraction for PCR reactions targeting cagA and vacA. • Histopathology: Biopsy slides were stained for histological assessment. H. pylori density, chronic inflammation, neutrophil activity, glandular atrophy, and intestinal metaplasia were scored

14. Primary Research Article Contributing to the Understanding of the Disease caused by H. pylori • Results • Fig. 1 Histological parameters determined in antral biopsy specimens and H. pylori cagA status. H. pylori density (a), neutrophil activity (b), chronic inflammation (c), glandular atrophy (d), and intestinal metaplasia (e) are illustrated

15. Primary Research Article Contributing to the Understanding of the Disease caused by H. pylori • Results: H. pylori strains showing cagA positivity had significantly higher neutrophil activity, chronic inflammation, and glandular atrophy in biopsy specimens from dyspeptic patients • This article supports the case study by demonstrating the virulence factors of H. pylori are associated with more severe gastritis

16. Take Home Message • Disease involves chronic gastritis and peptic ulcers • Typical symptoms are nausea, epigastric pain, vomiting, anorexia • Pathogen is Helicobacter pylori • Diagnostic tests include biopsy, urea breath test • Therapy is based on a combination of antimicrobials • Low chance of reinfection once eradicated • Clean and hygienic living conditions help prevent infections • Transmission is via person to person • Threat is prevalent, about half of the world’s population is infected. Severity of symptoms depend on region, age, and lifestyle

17. References • Johannes G. Kusters,* Arnoud H. M. van Vliet, and Ernst J. Kuipers, Pathogenesis of Helicobacter pylori Infection. Clinical Microbiology Reviews, 2006, 19(3): 449-490. • Bodo Linz, François Balloux, Yoshan Moodley et al, 2007, An African origin for the intimate association between humans and Helicobacter pylori. Nature, 2007 445(7130): 915–918. • McQueen, Nancy. Winter 2009. Campylobacteriaceae (And Campylobacter-like species) • Hasan Umit, et al, The Relationship Between Virulence Factors of Helicobacter pylori and Severity of Gastritis in Infected Patients. Digestive Diseases and Sciences, 2008, 54(1): 103-110.

18. Acknowledgments Dr. Nancy McQueen Omar Ahmed Hank Hsieh Rochelle Songco