1. Objectives By the end of this lecture the student must be:
A) Identify the genus Campylobacter & Helicobacter
B) describe the chemical tests for this genus
C) Differentiate between different sps.
D) List and match the symptoms, diagnosis and treatment for different sps.

2. Campylobacter
Campylobacter is the main causative agent of diarrhoea (enteritis ), mainly children, in developing countries
C. jejuni, E. coli and Rotavirus are the three most common cause of infantile diarrhoea in the world
Infections usually sporadic, occurring in summer
Mode of transmission
Acquired by the fecal-oral route via ingestion of;
Improperly handled or cooked food primarily poultry
Also, drinking of un-pasteurized milk
Children is the most commonly affected worldwide
Incubation period
The illness appears to last from 2-7 days

3. Pathogenesis and Virulence factor
C. jejuni infection vary considerably from asymptomatic to severe bloody diarrhea, high fever, and prostration
Enterocolitis begins as watery, foul smelling diarrhoea followed by bloody stools accompanied by fever, headache and sever abdominal cramps
Systemic infection: bacteremia (very rare)
Rarely C. jejuni spreads systematically (bacteremia) This organism multiply in the small intestine, invade the epithelium and produce gastroenteritis
Then C. jejuni secretes
Enterotoxin similar to cholera toxin and LT of E. coli
Cytotoxin that destroy mucosal cell

4. Diagnosis of C. jejuni Specimen Stool culture is done on:
Selective medium (Skirrow’s medium, Blood agar + cefoperazone, vancomycin, amphotericin B)
Incubation temperature at 420C in microaerophilic condition (5%CO2, 10%O2 & 85%N2) for hrs
Gram-stain
Gram stain examination of the colony should be performed along with oxidase test
Oxidase +ve colony exhibiting characteristic Gram stain appearance can be reported as Campylobacter

5. Diagnosis & Treatment Special test for C. jejuni
Hippurate hydrolysis is the major test for distinguishing between C. jejuni (positive) and other Campylobacter spp.
Treatment
Campylobacter jejuni isolates have variable susceptibilities to a variety of antimicrobials
Azithromycin and erythromycin (Macrolides) are the drug of choice

6. 4. Helicobacter Helicobacter is closely resemble to Campylobacter
Gram-negative spiral bacilli
Non-spore forming
Motile by multiple polar flagella
Microaerophilic
Grow at 370C and slow growing organism (7-10 days)
Requires enriched media with blood, hemin
Such supplements protects the organism from oxygen free radicals, H2O2 and fatty acids present in the media
Oxidase and catalase positive
Helicobacter is urease +ve while Campylobacter -ve
It survives in acidic environment of stomach & duodenum
It hides in mucus & neutralizes acid in its local environment

7. Diseases Associated with H. pylori
Gastritis (irritation & inflammation of lining of stomach)
Symptoms include nausea, vomiting and frequent complaints about pain in the abdomen
Peptic and duodenal ulcer
Sores that form in the stomach or the duodenum
The common symptom is burning pain in abdomen
Ulcers that bleed, causing hematemesis (bloody vomit or vomit that looks like coffee grounds) or melena (stool that's black, bloody or looks like tar)
Stomach cancer later in life
No bacteremia or disseminated diseases occurs

8. Mode of transmission
Scientists suspect that H. pylori infection may be contagious
The infection seems to run in families
More common in crowded or unsanitary conditions
Infection may be passed from person to person??
How spread happens isn't really known
Transmission believed to be by fecal-oral route

9. Pathogenesis Virulence Factors
Most bacteria killed in environment of gastric lumen 
H. pylori proliferates in mucus layer by aid of flagella
Then reach epithelial cells underneath- more neutral pH
H. pylori survives because of virulence factors that contribute to gastric inflammation, alter gastric acid production and cause tissue destruction
Virulence Factors
Initial colonization facilitated by:
Acid inhibitory protein - blocks acid secretion from parietal cells during acute infection
Urease - neutralizes gastric acids due to NH3 production
Urease stimulates monocytes and neutrophil chemotaxis; stimulates production of inflammatory cytokines

10. Heat shock protein - enhances urease expression; co-expressed with urease on bacterial surface
Flagella - allows penetration into gastric mucous layer
Adhesins - mediate binding to host cells
Localized tissue damage mediated by:
Mucinases and phospholipases - disrupt gastric mucus
Vacuolating cytotoxin - induces vacuolation in epithelial cells that results in epithelial cell damage
SOD and catalase - prevent from phagocytosis and intracellular killing

11. Diagnosis H. pylori is diagnosed by non-culture method such as
Blood antibody tests
Urea breath tests (UBT)
Endoscopic biopsies
Stool antigen tests
H. pylori isolated by culture of gastric biopsy on non-selective media enriched with blood or serum for 7-10 day
Skirrow’s media supplemented with blood or serum

12. Diagnosis Blood antibody test
Blood tests for the presence of antibodies to H. pylori can be performed easily and rapidly
Urea Breath Test (UBT)
UBT is a safe, easy & accurate test for detection of H. pylori
UBT relies on ability of H. pylori to hydrolyse urea into CO2
CO2 is absorbed from stomach & eliminated in the breath
10-20 minute after swallowing a capsule containing a minute amount of radioactive urea, a breath is collected
The presence of radioactive CO2 in the breath (a positive test) means that there is active infection

13. Test kit showing negative and positive results for Helicobacter
Endoscopic biopsies
Endoscopy is an accurate test for diagnosing H. pylori as well as the inflammation and ulcers that it causes
For endoscopy, the doctor inserts a flexible viewing tube (endoscope) through the mouth, down the oesophagus, and into the stomach and duodenum
During endoscopy, small tissue samples (biopsies) from the stomach lining can be removed
A biopsy is placed on a special slide containing urea
If the urea is broken down, this means that there is an infection with H. pylori
Test kit showing negative and positive results for Helicobacter

14. Treatment of H. pylori
The regimen most commonly recommended for first line treatment of H. pylori is triple therapy with a PPI (lansoprazole 30 mg twice daily, omeprazole 20 mg twice daily, pantoprazole 40 mg twice daily, rabeprazole 20 mg twice daily, or esomeprazole 40 mg once daily), amoxicillin (1 g twice daily), and clarithromycin (500 mg twice daily) for 7 to 14 days. We suggest treatment for 10 days to two weeks.