CAMPYLOBACTER
DEFINITION:
Gram negative rods, motile, oxygen concentration for growth is 5%,
catalase positive (or negative), oxidase positive, don't react with
sugars, nitrate reduced to nitrite, indole negative.
SPECIES:
1- C. jejuni. grows at 42°C and causes enterocolitis.
2- C. intestinalis, do not grow at 42°C. and causes bacteraemia.
PATHOGENSIS and CLINICAL FINDINGS:
It has an enterotoxin that acts by the same process as that of cholera
enterotoxin. It acts also by direct invasion in the tissues and
intestine. This leads to bloody diarrhoea. It causes enterocolitis
(in children) and bacteraemia in all ages. In enterocolitis the
atient develops watery, foul-smelling diarrhoea, bloody stool,
fever and abdominal pain. In bacteraemia the patient suffers
from fever and malaise, without physical signs.
LABORATORY DIAGNOSIS:
1- Specimens Collected: Stool, blood.
2- Microscopy: Gram negative, curved rods, appear as comma-shape
or S- shape, has darting motility.
3. Culture: Use selective blood agar medium containing antibiotics. Temperature of incubation is 42°C or 37°C. Atmosphere is microaerophilic. Butzler selective medium and Skirrow selective medium may be inoculated for culture. Blood may be cultured in cases of bacteraemia.
4. Identification: By the following methods:
a) C. jejuni fails to grow at 25°C, oxidase positive and sensitive
to nalidixic acid.
b) C. intestinalis is identified by its failure to grow at 42°C,
grows at 25°C, and resistant to nalidixic acid.
EPIDEMIOLOGY and PREVENTION:
Sources of infection to humans are domestic animals, e.g.: cattle,
chickens & dogs. Transmission is by faecal-oral route. C. jejuni is the
most common species causing infection. Prevention by Proper sewage
disposal and personal hygiene. No vaccine developed
DEFINITION:
Gram negative rods, motile, oxygen concentration for growth is 5%,
catalase positive (or negative), oxidase positive, don't react with
sugars, nitrate reduced to nitrite, indole negative.
SPECIES:
1- C. jejuni. grows at 42°C and causes enterocolitis.
2- C. intestinalis, do not grow at 42°C. and causes bacteraemia.
PATHOGENSIS and CLINICAL FINDINGS:
It has an enterotoxin that acts by the same process as that of cholera
enterotoxin. It acts also by direct invasion in the tissues and
intestine. This leads to bloody diarrhoea. It causes enterocolitis
(in children) and bacteraemia in all ages. In enterocolitis the
atient develops watery, foul-smelling diarrhoea, bloody stool,
fever and abdominal pain. In bacteraemia the patient suffers
from fever and malaise, without physical signs.
LABORATORY DIAGNOSIS:
1- Specimens Collected: Stool, blood.
2- Microscopy: Gram negative, curved rods, appear as comma-shape
or S- shape, has darting motility.
3. Culture: Use selective blood agar medium containing antibiotics. Temperature of incubation is 42°C or 37°C. Atmosphere is microaerophilic. Butzler selective medium and Skirrow selective medium may be inoculated for culture. Blood may be cultured in cases of bacteraemia.
4. Identification: By the following methods:
a) C. jejuni fails to grow at 25°C, oxidase positive and sensitive
to nalidixic acid.
b) C. intestinalis is identified by its failure to grow at 42°C,
grows at 25°C, and resistant to nalidixic acid.
EPIDEMIOLOGY and PREVENTION:
Sources of infection to humans are domestic animals, e.g.: cattle,
chickens & dogs. Transmission is by faecal-oral route. C. jejuni is the
most common species causing infection. Prevention by Proper sewage
disposal and personal hygiene. No vaccine developed
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