Helicobacter

Question 1

Helicobacter morphology

Answer 1

Gram -ve rods
Curved spiral shaped
Motile with unipolar lophotrichous flagella
Non spore forming
Microaerophillic
Grows at ph 6-7
Urease +
Catalase +
Oxidase +

Question 2

Important species of helicobacter

Answer 2

Helicobacter pylori

Question 3

Diseases caused by h pylori

Answer 3

Antral gastritis
Gastric ulcers
Peptic ulcer disease
Risk factor for gastric adeno Ca
Linked tobgastric MALToma

Question 4

Virulence factors

Answer 4

Flagella
Urease
Type 4 secretion system
Secretory enzyme
Exotoxin
Outer protein

Question 5

Transmission of h pylori

Answer 5

Habitat- human stomach transmitted by ingestion
Person to person transmission occur because of clustering of infection within families.
Has not been isolated from food drink or stool

Question 6

Pathogenesis of h pylori

Answer 6

1.H pylori attaches to the mucous secreting cells of gastric mucosa
2. It produces large amount of NH3 from urea by its urease
3. NH3 neutralizes the gastric acid (increases ph) and allows the organism to survive.
4. Produces protease and modifies gastric mucosa
5. Bacterial toxin , lps and nh3 damages the mucosal cell.
6. Loss of protective mucous coating.
7. Predisposes to gastritis and peptic ulcer

Question 7

Clinical features of h pylori

Answer 7

1. Gastritis and peptic ulcer is characterised by recurrent pain in upper abdomen.. nausea vomiting bleeding into GIT
2. Once colonized the infection persists for years or life time

Question 8

Lab diagnosis of h pylori

Answer 8

Specimen
Smears
Culture
Detection of abs
Special tests
Antigen detection test
Biochemical test
Rapid urease test

Question 9

Specimen

Answer 9

1.Gastric biopsy material obtained by gastroscopy and endoscopy
2. Blood for serological test
3. Stool for ag detection

Question 10

Smear

Answer 10

1. Giemsa/ special silver stain shows curved or spiral shaped organism
2. Histopathological examination to demonstrate gastritis

Question 11

Culture

Answer 11

Skirrows media
Incubate at 37° in microaerophilic environment
Grows in 3-6 days

Question 12

Special tests

Answer 12

1. Urea breath test: to detect urrease activity.
   Radio labelled urea is ingested by pt.
   If h pylori is present urease will cleave the ingested urea.
   Radiolabelled co2 is evolved that can be detected in pts exhaled breath by using spectrometer.
   Radiolabelled co2 goes to gastric vein to blood to heart to lungs and exhaled

Question 13

Antigen detection test

Answer 13

Test for helicobacter ag in the stool for confirmations that the treatment has eliminated the organism

Question 14

Biochemical test

Answer 14

Oxidase +
Catalase +
Strong production of urease

Question 15

Rapid urease test

Answer 15

Gastric biopsy material in a media containg urea with indicator.
Urease of h pylori cleaves it .
Produces NH3
It is detected by ph meter in media
Urease +ve
If h pylori is present colour change occurs from pale to pink in 1-2 days