Campylobacter, Helicobacter pylori Lecture Notes

Campylobacter

• Small gram negative rods spiral seagull or S shaped

• Darting cock screw like motilty

• Zoonosis

• Undercooked poultry and meat major source of infection in humans

• Foodborne

• Enetrocolitis with diarrhoea,followed by bloody stools with fever and abdominal pain

• Lab diagnosis

• Morphology culture on Preston media CCDA agar

• microaerophilic

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Helicobacter pylori

• H.pylori causes gastritis and peptic ulcers.

• risk factor for gastric carcinoma

• Diagnosis

• Gastric biosies by

• Smears stained with gram or special stains which show curved rods

• Culture

• Detection of h.pylori in serum

• Urea breath test or urease positive

image

Virulence factors and biochemical properties

• Somatic O antigens heat stable found in cell wall

• K antigens-capsular polysaccride or protein antigens

• Heat labile surround cell wall S.typhi (Vi antigen)

• F –fimbriae associated antigens

• H antigens-

• flageller protein antigens by motile enterobacteria.heat labil

• The antigens are detected by agglutination with specific antibodies.

• The heat labile K antigens may interfere with detection of O antigens

• Enterobacteria are aerobes and facultative aneorobes,non sporing ,motile or non-motile

• Oxidase negative

• Reduce nitrate to nitrite and ferment glucose.(API)

• Exotoxin

• (enterotoxin –shigella dysenteriae and toxigenic strains of E.coli

• Endotoxin released from cell wall when lysed

Eenterobacteriacea

• Some of the common nosocomial infections are urinary tract infections,

• respiratory pneumonia,

• surgical site wound infections,

• bacteremia, gastrointestinal

• and skin infections.

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