Vibrio, Campylobacter, Helicobacter

Question 1

Where vibrios are found ?

Answer 1

Mainly in water

Widespread in nature

Question 2

Vibrios characteristics?

Answer 2

Short, curved, gram negative bacilli ( color pink or red)
Motile
Oxidase positive

Question 3

Mention non halophilc vibrios ( cant live in salt water) ?

Answer 3

V.cholerae

Question 4

Mention halophilic vibrios

Answer 4

V.parahemolyticus

V.vulnificus

Question 5

How do vicholerae transmit ?

Answer 5

By drinking contaminated water

There is no need for vector

Question 6

What is the habitat for vicholerae ?

Answer 6

Water contaminated with fece s of patients or carriers

Question 7

Epidemiology of vicholerae 8

Answer 7

Pandemis and epidemics : cindia and bangladish, east asia, africa)

Question 8

Morphology of vicholerae?

Answer 8

Gram-negative slender bacilli (comma shaped) motile , non-capsulated

Question 9

Culture of v.cholerae?

Answer 9

Aerobe
Enrichment media : alkaline peptone water.
Selective media : tcbs media
Observe yellow colonies

Question 10

Laboratory diagnosis of v.cholerae

Answer 10

Somatic (o) antigen structure
V.cholerae: ol antigen (vibrio cholerae o1)
Non o1 v.cholerae: no antigen

Question 11

What is the pathogenisity of v.cholerae ?

Answer 11

• febrile diarhoeal illness (sever)
• vomiting
• rapid dehydration and hypovolemic shock
• death can occur in 12-24 hrs
• Produce enteritoxin
• Causes irreversible activation of cAMP
• Blocks the uptake of water which accompanies Na and Cl absorption
• Passive movement of water leading to serious loss of water
• Infective dose is small
• Multiply in small intestine

Question 12

V.cholerae non 01 pathogenisity (without somatic antigen) :

Answer 12

• causes mild, sometimes bloody diarrhoea
• accompanied by abdominal cramps
• may produce toxins
• can also cause epidemics

Question 13

V.parahemolyticus

Halophilic or non halophilic vibrio?

Answer 13

Halophilic vibrio (salt-tolernt)

Question 14

What does v. Parahemolyticus Cause?

Answer 14

Acute gastroenteritis (food poisoning)

Question 15

Pathogenisity of parahemolyticus:

Answer 15

causes explosive diarrhoea
Self limiting (3 days)
Abdominal pain, nausea and vomiting
Related to ingestion of sea food (fish and shellfish)→ not only man there is a vector that transmit the disease.

Question 16

Laboratory diagnosis of v.parahemolyticus :

Answer 16

Non-sucrose fermenter on tcbs

Green colonies

Question 17

V.vulnificus : halophilc or non halophilic vibrio

What it is associated with ?

Answer 17

Halophilic vibrio

it is associated with warm water environment

Question 18

What are the 3 main clinical syndromes of v.vulnificus?

Answer 18

1. Rapid onset fulminating septicemia followed by cutaneous lesions shell fish )
2. Rapid onset cellulitis
3. Acute diarrhoea following consumption of shell fish .

Question 19

What is the pathogenesis of v.vulnificus?

Answer 19

Virulence associated with polysacchride capsule.

Question 20

What are the characteristics of campylobacter ?

Answer 20

1.c.jejuni 2.c.coli
Small spiral gram negative bacilli
Motile
No spores
Oxidase positive

Question 21

C. Jejuni and c-coli pathogenesis

Answer 21

caused by food poisoning
Infection acquired by ingestion
The commonest cause of infective diarrhea in developed conntries. Animals are the main source : poultry and raw meat.
Small infective dose
Involvement of both small and large intestine
Causes invasive disease
Do not multiply in food (salmonellosis)

Question 22

C. Jejuni andc.coli clinical manifestation.

Answer 22

Sever abdominal pain 
diarrhoeal /bloody
Fever
Complications: 
gi hemorrhage 
toxic megacolon 
hus 
reactive arthritis

Question 23

C. Jejuni and c.coli laboratory diagnosis

Answer 23

Stool Culture 
Selective media: charcoal -based media containing antibiotics 
microaerophilic environment for growth
Temperature 42 -43°c 
c.jejuni (the commenest) :
Hydrolyse hippurate
90-95% of infections

Question 24

Helicobacter pylori description:

Answer 24

Gram -negative spirally-shaped
microcerophilic
man appears to be the only reservoir
oral-oral or facal-oral rout for transmission

Question 25

Helicobacter pylori pathogenesis:

Answer 25

Live only in gastric mucosa
ip few days
symptoms of abdominal pain , nausea
lasts for 2 weeks
minority of patients develop peptic ulcer
long standing infection associated gastric cancer

Question 26

Helicobacter pylori labratory diagnosis:

Answer 26

Invasive tests : 
 sample of gastric mucosa
       microscopy 
       culture 
       biopsy urease test (small portion of the biopsy put in small quantity of urease solution (indicator, amonia production and change in ph)

Non invasive tests :
Serology :ELISA
Urea breath

Question 27

Peptic ulceration : pathogenic mechanism

Answer 27

The production of amonia by urease which causes ionic changes in the mucus layer of the stomach
Production of toxins as lipopolysaccharide that activate inflammatory cells
Stimulation of an auto-immune response by production of antigens that cross-react with antral gastric antigens
The degradation of mucus by a protease