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.

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

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

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 48-72 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

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

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

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

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

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

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

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

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

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

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.