TYPES OF CULTURE MEDIA-II

TYPES OF CULTURE MEDIA-II

Q. 1

Loeffler’s syndrome is seen with all except :

 A >Toxocara
 B >Strongyloides stercoralisL. tryptophan
 C >Giardiasis
 D Giardiasis
Q. 1

Loeffler’s syndrome is seen with all except :

 A >Toxocara
 B >Strongyloides stercoralisL. tryptophan
 C >Giardiasis
 D Giardiasis
Ans. D

Explanation:

Giardiasis [Ref. Harrison 161h/e p 1520]

  • Pulmonary diseases associated with tissue or blood eosinophilia are a heterogenous group of disorders.
  • They are classified as :

Loeffler’s syndrome

  • It is a benign acute eosinophilic pneumonia of unknown cause characterized by migrating pulmonary infiltrates and minimal clinical manifestations.
  • These are usually secondary to parasites or drugs.
  • Loeffler’s syndrome reflects a hypersensitive response to an ingested or inhaled antigen from food, medication or an infectious agent. Causes of Loeffler’s syndrome

Parasitic infections

  • Ascaris
  • Schistosomiasis
  • Strongyloides
  • Ancyclostomiasis
  • Trichomoniasis
  • Clonorchiasis
  • Visceral larva migrans
  • Tapeworm
  • Paragonimiasis

Q. 2 A child presents with a white patch over the tonsils; diagnosis is best made by culture in:

 A

Loeffler medium

 B

LJ medium

 C

Blood agar

 D

Tellurite medium

Q. 2

A child presents with a white patch over the tonsils; diagnosis is best made by culture in:

 A

Loeffler medium

 B

LJ medium

 C

Blood agar

 D

Tellurite medium

Ans. A

Explanation:

In the child presenting with a white patch over the tonsil, we suspect a diagnosis of ‘diphtheria’. Usual media used for cultivation of Diphtheria are Loeffler’s serum slope & tellurite blood agar.
 
Ref: Text Book of Microbilogy By Ananthanarayan, 6th Edition, Page 215 and 8th Edition, Page 233

Q. 3

Culture medium for cultivation of mycobacterium is:
September 2005 & 2011

 A

Ludlam’s medium

 B

Loeffler’s serum

 C

Thayer-Martin medium

 D

LJ medium

Q. 3

Culture medium for cultivation of mycobacterium is:
September 2005 & 2011

 A

Ludlam’s medium

 B

Loeffler’s serum

 C

Thayer-Martin medium

 D

LJ medium

Ans. D

Explanation:

Ans. D: LJ medium
Diagnosis of tuberculosis
Microscopy

– Rapid diagnosis

– Low sensitivity. Concentration may increase sensitivity up to hundred folds

– Can not differentiate tuberculosis and non-tuberculosis mycobacteria

– False positive results

– Samples must always be studied with one positive and one negative control

Culture

– The gold standard method for tb diagnosis

Culture in LJ media takes 3 to 6 weeks

– Commonly used rapid culture systems have disadvantages:

  1. Radioactive, expensive, blood containing samples give false results
  2. All culture methods require decontamination

When grown on LJ medium, M. tuberculosis appears as brown, granular colonies (sometimes called “buff, rough and tough”). The media must be incubated for a significant length of time, usually four weeks, due to the slow doubling time of M. tuberculosis compared with other bacteria (15-20 hours).

Lowenstein-Jensen (g) medium is most widely used for tuberculosis culture.

LJ medium containing glycerol favours the growth of M. tuberculosis while LJ medium without glycerol but containing pyruvate encourages the growth of M. bovis. Both should be used in countries or regions where patients may be infected with either organism.

Ingredients

Mineral salt solution

Potassium dihydrogen phosphate anhydrous (1(1-12PO4) 2.4g Magnesium sulphate (MgSO4. 7H20) 0.24g

Magnesium citrate 0.6g

Asparagine 3.6g

Glycerol (reagent grade) 12m1

Distilled water 600m1

Quiz In Between


Q. 4 Role of Malachite green in LJ medium

 A

Increase growth of M. tuberculosis

 B

Inhibits growth of other bacteria

 C

Nutritive value

 D

As an indicator

Q. 4

Role of Malachite green in LJ medium

 A

Increase growth of M. tuberculosis

 B

Inhibits growth of other bacteria

 C

Nutritive value

 D

As an indicator

Ans. B

Explanation:

Ans. is ‘b’ i.e., Inhibits growth of other bacteria

Lowenstein-Jensen Medium (LJ medium)

LJ medium consists of mineral salts, asparagine, glycerol, malachite green and hen’s egg.

The malachite green prevents the growth of other microorganism on medium.

It is used as a primary isolation medium for mycobacteria.


Q. 5

Example of selective medium is:

 A LJ medium

 B

Blood agar

 C

Selenite F broth

 D

Chocolate agar

Q. 5

Example of selective medium is:

 A

LJ medium

 B

Blood agar

 C

Selenite F broth

 D

Chocolate agar

Ans. A

Explanation:

Ans. is. ‘a’ i. e., LJ medium


Q. 6

Which of following Culture media combination is/are true except:

 A

Thayer-Martin media: Gonorrhoea

 B

Chocolate agar-: enriched media

 C

Lowenstein-Jensen Medium: Mycobacterium tuberculosis

 D

Muller-Hinton agar: Corynebacterium diphtheriae

Q. 6

Which of following Culture media combination is/are true except:

 A

Thayer-Martin media: Gonorrhoea

 B

Chocolate agar-: enriched media

 C

Lowenstein-Jensen Medium: Mycobacterium tuberculosis

 D

Muller-Hinton agar: Corynebacterium diphtheriae

Ans. D

Explanation:

Ans: d. Muller-Hinton…[Ref Ananthanarayan 8th/39-43, 229]

  • Thayer-Martin is a useful selective media for Neisseria gonorrhoeae”.
  • Mueller-Hinton is enriched media for Neisseria.
  • C diphtheriae and other corynebacteria grow aerobically on most ordinary laboratory media. On Loeffler’s serum medium, corynebacteria grow much more readily than other respiratory organisms, and the morphology of organisms is typical in smears.
  • Lowenstein-Jensen Medium. It is used to culture tubercle bacilli. It contains egg, malachite green and glycerol.
  • Chocolate Agar or Heated Blood agar: Prepared by heating blood agar. It is used for culture of pneumococcus, gonococcus, meningococcus and Haemophilus. Heating the blood inactivates inhibitor of growths.

Quiz In Between



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