Campylobacter jejuni
| A | Temperature of 42°C and microaerophilic | |
| B |
Temperature of 42°C and 10% carbon dioxide |
|
| C |
Temperature of 37°C and microaerophilic |
|
| D |
Temperature of 37°C and 10% carbon dioxide |
A child was diagnosed to be suffering from diarrhoea due to Compylobacter jejuni. Which of the following represents the correct environmental conditions for incubation of the culture plates of the stool sample?
| A |
Temperature of 42°C and microaerophilic |
|
| B |
Temperature of 42°C and 10% carbon dioxide |
|
| C |
Temperature of 37°C and microaerophilic |
|
| D |
Temperature of 37°C and 10% carbon dioxide |
A 53 year old woman with diarrhea and lower abdominal pain of 3 days duration comes to her physician after failing to relieve her symptoms with various home remedies. She denies any recent travel and states that there is blood and pus in her stool. Fecal cultures yield several flagellated, curved, oxidase positive, gram negative rods. The organism isolated is most likely ?
| A |
Campylobacter jejuni |
|
| B |
Escherichia coli |
|
| C |
Salmonella |
|
| D |
Shigella |
Regarding Campylobacter jejuni not true is ‑
| A |
Most common cause of Campylobacteriosis |
|
| B |
Poultry is the cause of the disease |
|
| C |
Human is the only reservoir |
|
| D |
Causes Gillian barrie syndrome |
Ans. is ‘c’ i.e. Human is the only reservoir
Animals are the main reservoir of C. jejuni( not human). It is a zoonosis.
CAMPYLOBACTER
Morphology
. Gram negative
. Comma shaped
. Motile with a single polar flagellum —> Darting or tumbling motility
. Non capsulated
. Nonsporing
Culture
. Growth occurs under microaerophilic conditions (5% 02,10% CO2 and 85% N2).
. Thermophilic, growing at 42°C (Can grow at 37°C, but incubation at higher tempratures suppresses normal fecal flora.)
Biochemical reactions
. Do not ferment carbohydrate
. Catalase and oxidase positive
. Nitrate reduction positive
Pathogenicity
Diarrhea! disease
. C. jejuni is the most common cause
. It is a zoonosis
. The source is food of animal origin, especially raw milk.
| A | Culture on TCBS medium incubated at 37°C under aerobic conditions | |
| B |
Culture on Skirrow’s medium incubated at 42°C under micro-aerophilic conditions. |
|
| C |
Culture on MacConkey’s medium incubated at 42°C under anaerobic contions |
|
| D |
Culture on Wilson and Blair’s medium incubated at 37° under microaerophilic conditions |
Ans. is ‘b’ i.e., Culture on skirrow’s medium incubated at 42°C under micro-aerophilic conditions
. Compylobacter jejuni is thermophilic, growing well at 42°C. Inoculated plates are incubated under microaerophilic conditions with an atmosphere of 5% 02, 10% CO2 and 85% N2 at 42°C.
. Plating media commonly used are
1) Skirrow’s medium
2) Butzler’s medium
3) Campy BAP medium
. Transport medium
– Cary-Blair medium
. The jejunum and the ileum are the primary sites of colonization.
. C. jejuni is invasive pathogen, may involve mesentric lymph node and cause bacteremia.
Treatment
. Most cases resolve without antimicrobial therapy with fluid and electrolyte replacement.
. When needed, erythromycin is the drug of choice.
| A | Clostridium tetani | |
| B |
Corynebacterium diphtheria |
|
| C |
Campylobacter jejuni |
|
| D |
Helicobactor pylori |
Ans. is ‘c’ i.e., Campylobacter jejuni
. Media used for cultivation of H. Pylori are :
i) Skirrow’s medium
Butzler’s medium
iii) Compy BAP medium
| A | Obligate aerobe | |
| B |
Oxidase negative |
|
| C |
Grows at 42°C |
|
| D |
Non-motile |
Ans. is ‘C’ i.e., Grows at 42°C
Campylobacter jejuni
Morphology
-
Gram-negative
-
Comma shaped
-
Motile with a single polar flagellum → Darting or tumbling motility
-
Non-capsulated
-
Non-Sporing
Culture
-
Growth occurs under microaerophilic conditions (5% O2, 10% CO2 and 85% N2).
-
Thermophilic, growing at 42°C (Can grow at 37°C, but incubation at higher temperatures suppresses normal fecal flora.)
Biochemical reactions
-
Do not ferment carbohydrate
-
Catalase and oxidase-positive
-
Nitrate reduction positive
| A | Vibrio cholerae | |
| B |
Shigella |
|
| C |
Campylobacter jejuni |
|
| D |
Yersinia enterocolitica |
Ans. is ‘c’ i.e., Campylobacter jejuni
This is a case of dysentery (RBC in stools along with WBC).
Among the given options, ‘b’, ‘c’ and ‘d’ can cause dysentery. But, the comma-shaped organism is a campylobacter jejuni.
Based on the depth of intestinal invasion, there are different clinical manifestations of infection with organisms causing diarrhea:-
No cell invasion (noninflammatory)
-
The bacteria bind to intestinal epithelial cells but do not enter the cell.
-
Diarrhea is caused by the release of enterotoxins.
-
Watery diarrhea with no fecal leukocytes and no systemic symptoms (e.g. fever) occurs.
Organisms are :
-
V. cholerae
-
Clostridium perfringens
-
Cryptosporidium
-
Adenovirus
-
ETEC
-
B. cereus
-
Microsporidia
-
Staph. aureus
-
Giardia
-
Rotavirus
Invasion of the intestinal epithelial cells (Inflammatory)
-
The organisms have virulence factors that allow binding and invasion into cells.
-
Toxins may be then released that destroy the cell.
-
The cell penetration results in a systemic immune response with fecal leukocytes as well as fever.
-
The cell death results in RBC leakage into the stool (dysentery).
| A |
BYCE medium |
|
| B |
Skirrow’s medium |
|
| C |
Thayer-Martin medium |
|
| D |
TCBS medium |
Ans. is ‘b’ i.e., Skirrow’s medium
