CAMPYLOBACTER AND HELICOBACTER

1. CAMPYLOBACTER AND HELICOBACTER

2. A 21 year-old woman presents to the emergency room with shortness of breath 2 weeks after recovering from a "stomach flu." Physical exam reveals ascending muscle weakness that began in her toes. Cardiac irregularities are also notable. A review of the patient's chart revealed that a bacterial stool culture 2 weeks earlier, during the patient's "flu" episode, found comma shaped organisms growing at 42°C (107.6°F). Which of the following pairs represents the causative agent of this patient's flu and the post-flu condition, respectively? • A. Campylobacter jejuni, Guillain-Barre syndrome • B. Clostridium botulinum, botulism • C. JC virus, progressive multifocal leukoencephalopathy (PML) • D. Poliovirus, poliomyelitis

3. CAMPYLOBACTER • Gram negative, curved, micro-aerophilic bacteria found in the intestine of animals. • Diseases range from mild diarrhea to dysentery

4. Common species

5. Bacteriology • GNB, curved or S shaped bacilli (gull winged shape) • Motile with uni / bipolar flagellae • Microaerophilic • Non fermenting • Oxidase positive

6. Electron micrograph showing polar flagella Gram’s stain

7. Major virulence factors • Motility • Invasion • Enterotoxins

8. Pathogenesis • Source of infection –infected animals, contaminated food ( raw milk, poutry etc), patients • Transmission – ingestion of contaminated food, pet animals, feco-oral • Incubation period – 5-7days • Bacteria colonizes small and large intestine, invades and produces enterotoxins

9. Clinical Disease • Watery diarrhea • Bloody diarrhea with fever, abdominal cramps • Bacteremia, septicemia, meningitis • Associated with GuillianBarre Syndrome Disease takes severe form in immunocompromised patients and young children GB syndrome: autoimmune (due to cross reactivity b/w oligosaccharides in bacterial capsule & glycospingo-lipids on peripheral nerve gangliosides)

10. Laboratory diagnosis • Fecal specimen and blood • Feces transported in Cary Blair medium • Microscopy: Gram’s stain: inflammatory cells and small curved GNB • Culture media: Campy Blood agar with antibiotics –Skirrows medium • Incubation in microaerophilic environment requires 5% O2, 10% CO2 and 85% nitrogen

12. feces Hanging drop – motility Culture Gram negative curved bacilli Blood cells & pus cells Biochemical identification may be present oxidase + non fermenter Presumptive diagnosis hippurate hydrolysis+ Definitive diagnosis

13. Treatment • Erythromycin • Ciprofloxacin • Doxycycline

14. Helicobacter pylori • GNB, spiral shaped, motile, urease producing bacterium • First cultured in 1982(Marshall & Warren in Australia) – called campylobacter pylori • Later renamed Helicobacter pylori in 1989 • Inhabits mucus overlying gastric mucosa

15. Robin Warren (R) and Barry Marshall: discovered cause of peptic ulcers. Their controversial research eventually culminated in bold self-experimentation and led to a complete change in the treatment of the condition world-wide.In 2005 they were awarded the Nobel Prize for Medicine for their work

16. Epidemiology • Found in the stomach of individuals in all parts of world. • Also found in non human primates • Developing countries – 70-90% carry H. pylori, majority acquire in <10 yrs age • Developed countries – 25-50%, acquire in <20 yrs

17. Risk factors • Infected family member • Crowded living conditions • Clustering in day care centers, institutions • Poor sanitation • Poor hygeine • Hypo / Achlorhydria

18. Virulence factors • Motility & spiral shape • Urease • Phospolipase • Mucinase • Cytotoxins • Adhesins

20. Pathogenesis • Entry into gastric mucus • Attachment to gastric epithelial cells, mainly pylorus • Evasion of immune response • Persistent colonisation • Ulceration / inflammation • Transmission

21. Disease association • Chronic gastritis, may be asymptomatic • Peptic ulcer disease • Atophic gastritis • Gastric adenoma • Gastric lymphoma Gastric malignancies” - Virulence is associated with Cag(cytotoxin associated gene) and Vac (vacuolatingcytotoxin gene)

24. Lab diagnosis Using invasive methods – endoscopic biopsy • Histological examination of gastric tissue • Culture • Rapid biopsy urease test • DNA probe • PCR

25. Non invasive methods using gastric fluid, serum saliva, urine • Urea breath test • Serology – good epidemiological tool

26. Methods • Specimen transported in Stuarts mediumor saline • Histopathology using H & E stain, Giemsa, Warthin-Starry Silver stain, Alcian blue

27. Gastric biopsy

28. Culture • Culture using chocolate agar , campylobacter selective media • Requires micro-aerophilic environment with added CO2 • Identified using colony morphology and biochemical reactions

30. Urea breath test • Rapid reliable test for H.pylori infection • Ingestion of C labelled urea • Urease of bacteria breaks urea releasing labelled carbon • Exhaled carbon measured

32. Treatment Antibiotic + proton pump inhibitors + bismuth salts • Using these combinations various regimens available • Triple therpy • Quadruple therapy • Dual therapy

33. Treatment Antibiotics: Metronidazole, Erythromycin, Clarithromycin, Amoxicillin, Tetracycline PPI: omeprazole, ranitidine Bismuth salts: salycilate or subcitrate

34. MCQs

35. Which of the following is an important distinguishing characteristic of H. pylori as compared to Campylobacter species? • A. Oxidase production • B. Catalase production • C. Urease production • D. Curved shape • E. Polar flagellum

36. Human melioidosis is caused by • A) Burkholderia cepacia • B) Pseudomonas aeruginosa • C) Burkholderia pseudomallei • D) Pseudomonas putida

37. Pseudomonas aeruginosa causes all of the following infections EXCEPT • Burn wound infection • Post catheterisation urinary tract infection • Chronic otitis media • Sore throat in children

38. Which of the following tests is useful in the diagnosis of Salmonella carriers? • Widal Test • Blood Culture • Vi Agglutination Test • Weil Felix test

39. A 45-year-old man presents to the hospital vomiting blood. He is diagnosed with a perforated peptic ulcer. The causative agent discovered by gastric biopsy is a spiral gram-negative bacillus. What other long-term complications could this organism cause if not treated? • A. Skin ulcers • B. Esophagealvarices • C. Gastric MALT lymphomas • D. Colon cancer

40. Plague is transmitted to humans by bite of • A) Rat flea • B) Hard tick • C) Sand fly • D) Mite

41. All of the following are halophilic vibrios EXCEPT • A) Vibrio alginolyticus • B) Vibrio parahaemolyticus • C) Vibrio vulnificus • D) Vibrio cholerae

42. The following statements about TCBS medium are true EXCEPT • It is a Selective medium • Vibrio parahaemolyticus produces green colour colonies on TCBS • It consists of Thiosulphate, Cetrimide, Bile Salt, Sucrose • Vibrio cholerae produces Yellow colour colonies on TCBS

43. Which one of the following organisms produce large amounts of urease? • Escherichia coli • Salmonella typhi • Helicobacter pylori • Chlamydia trachomatis

44. Which one of the following is an example of Atypical mycobacteria • Mycobacterium bovis • Mycobacterium kansasii • Mycobacterium tuberculosis • Mycobacterium leprae

45. Stalactite growth is characteristic of- • A)Yersinia enterocolitica • B)Yersinia pestis • C)Pasteurella multocida • D)Francisella tularensis

46. 58-year-old man presents to the clinic with decreased appetite, nausea, vomiting, and upper abdominal pain. If the causative agent is a curved gram-negative rod with urease production, what treatment should be given to this patient? • A. Proton pump inhibitor and antibiotic • B. Proton pump inhibitor, antibiotic, and bismuth • C. Over-the-counter antacids and antibiotics • D. Nonsteroidal antiinflammatory drugs (NSAIDs)

47. Blue green pus is associated with infections caused by • Pseudomonas aeruginosa • Proteus spp. • Staphylococcus aureus • Acinetobacter spp.

48. Darting motility is shown by • ◦ Vibrio cholerae • ◦ Escherichia coli • ◦ Proteus spp. • ◦ Pseudomonas spp.

49. Which of the following toxin resembles cholera toxin? • A) Heat labile toxin of Escherichia coli • B) Diphtheria toxin of Corynebacterium diphtheriae • C) Heat stable toxin of Escherichia coli • D) Exotoxin A of Pseudomonas aeruginosa