types of culture- classification

types of culture- classification

Q. 1 An outbreak of streptococcal pharyngitis has occured in a remote village. In order to carry out the epidemiological investigations of the outbreak it is necessary to perform the culture of the throat swab of the patients suffering from the disease. The transport media of choice would be –

 A Salt mannitol media

 B

Pike’s media

 C

Stuart’s media

 D

Cary Blair media

Q. 1

An outbreak of streptococcal pharyngitis has occured in a remote village. In order to carry out the epidemiological investigations of the outbreak it is necessary to perform the culture of the throat swab of the patients suffering from the disease. The transport media of choice would be –

 A

Salt mannitol media

 B

Pike’s media

 C

Stuart’s media

 D

Cary Blair media

Ans. B

Explanation:

Ans. is ‘b’ i.e., Pike’s media

“For cultures, swabs should be collected under vision from the affected site and either plated immediately or sent to the laboratory in Pike’s medium (blood agar containing crystal violet and sodium azide)”.


Q. 2

Selective media for vibrio – 

 A

TCBS

 B

Stuart

 C

Skirrows

 D

MYPA

Ans. A

Explanation:

Ans. is ‘a’ i.e., TCBS 


Q. 3

Selective media for N. gonorrhoeae –

 A

Thayer martin media

 B

Smith noguchi media

 C

Proskaur and Bech media

 D

Bordet gongue, media

Ans. A

Explanation:

Ans. is ‘a’ i.e., Thayer martin media 


Q. 4

All selective media are correctly matched except ‑

 A

V cholerae – TCBS medium

 B

Pseudomonas – Cetrimide agar

 C

M tuberculosis – LJ medium

 D

Campylobacter – BCYE medium

Ans. D

Explanation:

Ans. is ‘d’ i.e., Campylobacter – BCYE medium

  • Campylobacter infection is diagnosed when a laboratory test detects Campylobacter bacteria in the stool (poop), body tissue, or fluids. 

  • The test could be a culture that isolates the bacteria or a rapid diagnostic test that detects the genetic material of the bacteria.

  • Skirrow medium, Campy BAP medium, Butler’s media used for Campylobacter

  • A comparison of Skirrow’s, Butzler’s, Blaser’s, Campy-BAP and Preston media for Campylobacter spp was made using human, animal and environmental specimens. 

  • Butzler’s medium gave the lowest insolation rate and Preston medium, which was the most selective, the highest isolation rate. Enrichment culture using Preston enrichment broth gave a higher isolation rate than direct plating onto Preston medium.


Q. 5 Selective media for Pseudomonas ‑

 A EMJH medium

 B

PALCAM agar

 C

PLET medium

 D

Cetrimide agar

Ans. D

Explanation:

Ans. is’ i.e., Cetrimide agar

Cetrimide and Dettol have been incorporated in the media for the selective isolation of pseudomonas.

Cetrimide agar is a selective media.  


Q. 6 Transport media for the bacteria shown in the photomicrograph below is ? 

 A

Alkaline peptone water.

 B

Cary – Blair medium.

 C

TC BS medium.


 D None of the above.

Ans. B

Explanation:

Ans:B.)Cary-Blair medium.

The bacteria marked by a black arrow in the photomicrograph is Vibrio Cholera.

Transport media for vibrio cholerae is Cary-Blair medium.

Transport media for fecal specimens
Media appropriate for the transport of fecal specimens that are suspected to contain Shigella, Vibrio cholerae, or Salmonella (including serotype Typhi) specimens are:
1. Cary-Blair transport medium

  • High pH (8.4)
  • Medium of choice for transport and preservation of V. cholera
  • Cary-Blair transport medium can be used to transport many bacterial enteric pathogens, including Shigella, Salmonella, and Vibrio cholerae

2. Amies’and Staurt’s transport media

  • Acceptable for Shigella and Salmonella (including ser. Typhi), but they are inferior to Cary-Blair for transport of V. cholerae.

3. Alkaline peptone water

  • This medium may be used to transport V. cholerae, but this medium is inferior to Cary-Blair and should be used only when Cary-Blair medium is not available.
  • It should not be used if subculture will be delayed more than 6 hours from the time of collection, because other organisms will overgrow vibrios after 6 hours.

4. Buffered glycerol saline (BGS)

  • It’s a liquid medium which can be used for Shigella but this transport medium is unsuitable for transport of V. cholerae.



Q. 7

Selective media for TB bacilli is:

 A

NNN media

 B

Dorset media

 C

LJ media

 D

Nutrient agar

Ans. B:C

Explanation:

Ans. (b) and (c) Dorset media and LJ media

Solid

Liquid

Lowenstein Jensen media (most widely used) Dubos contain Tween 80
Dorset egg media Middle Brook’s
Loeffler’s media Proskauer and Beck’s
Pawlowsky media Sula’s and Sautan
  • Selective agent inhibiting other bacteria in LJ media is Malachite green.
  • Human tubercle bacilli do not grow in presence of para-nitrobenzoic acid.
  • Traces of fatty acid is toxic for tubercle bacilli in culture media.
  • Optimum pH for M. tuberculosis: 6.4-7.0.

Other Options:

NNN media → For Leishmania donovani

Nutrient agar → Simple media

MacConkey media → Differential as well as indicator media for lactose and non-lactose fermenters.


Q. 8

A patient with acute onset of diarrhea comes to emer­gency. After culture on enriched media, colonies as shown below were visualized. Identify the causative organism:

 A Vibrio cholera

 B

Salmonella typhi

 C

Compylolacter jejuni

 D

E. coli 

Ans. A

Explanation:

Ans. is. ‘a’ i. e., Vibrio cholera



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types of culture- classification

types of culture- classification

Q. 1 An outbreak of streptococcal pharyngitis has occured in a remote village. In order to carry out the epidemiological investigations of the outbreak it is necessary to perform the culture of the throat swab of the patients suffering from the disease. The transport media of choice would be –

 A Salt mannitol media

 B

Pike’s media

 C

Stuart’s media

 D

Cary Blair media

Q. 1

An outbreak of streptococcal pharyngitis has occured in a remote village. In order to carry out the epidemiological investigations of the outbreak it is necessary to perform the culture of the throat swab of the patients suffering from the disease. The transport media of choice would be –

 A

Salt mannitol media

 B

Pike’s media

 C

Stuart’s media

 D

Cary Blair media

Ans. B

Explanation:

Ans. is ‘b’ i.e., Pike’s media

“For cultures, swabs should be collected under vision from the affected site and either plated immediately or sent to the laboratory in Pike’s medium (blood agar containing crystal violet and sodium azide)”.


Q. 2

Selective media for vibrio – 

 A

TCBS

 B

Stuart

 C

Skirrows

 D

MYPA

Ans. A

Explanation:

Ans. is ‘a’ i.e., TCBS 


Q. 3

Selective media for N. gonorrhoeae –

 A

Thayer martin media

 B

Smith noguchi media

 C

Proskaur and Bech media

 D

Bordet gongue, media

Ans. A

Explanation:

Ans. is ‘a’ i.e., Thayer martin media 


Q. 4

All selective media are correctly matched except ‑

 A

V cholerae – TCBS medium

 B

Pseudomonas – Cetrimide agar

 C

M tuberculosis – LJ medium

 D

Campylobacter – BCYE medium

Ans. D

Explanation:

Ans. is ‘d’ i.e., Campylobacter – BCYE medium

  • Campylobacter infection is diagnosed when a laboratory test detects Campylobacter bacteria in the stool (poop), body tissue, or fluids. 

  • The test could be a culture that isolates the bacteria or a rapid diagnostic test that detects the genetic material of the bacteria.

  • Skirrow medium, Campy BAP medium, Butler’s media used for Campylobacter

  • A comparison of Skirrow’s, Butzler’s, Blaser’s, Campy-BAP and Preston media for Campylobacter spp was made using human, animal and environmental specimens. 

  • Butzler’s medium gave the lowest insolation rate and Preston medium, which was the most selective, the highest isolation rate. Enrichment culture using Preston enrichment broth gave a higher isolation rate than direct plating onto Preston medium.


Q. 5 Selective media for Pseudomonas ‑

 A EMJH medium

 B

PALCAM agar

 C

PLET medium

 D

Cetrimide agar

Ans. D

Explanation:

Ans. is’ i.e., Cetrimide agar

Cetrimide and Dettol have been incorporated in the media for the selective isolation of pseudomonas.

Cetrimide agar is a selective media.  


Q. 6 Transport media for the bacteria shown in the photomicrograph below is ? 

 A

Alkaline peptone water.

 B

Cary – Blair medium.

 C

TC BS medium.


 D None of the above.

Ans. B

Explanation:

Ans:B.)Cary-Blair medium.

The bacteria marked by a black arrow in the photomicrograph is Vibrio Cholera.

Transport media for vibrio cholerae is Cary-Blair medium.

Transport media for fecal specimens
Media appropriate for the transport of fecal specimens that are suspected to contain Shigella, Vibrio cholerae, or Salmonella (including serotype Typhi) specimens are:
1. Cary-Blair transport medium

  • High pH (8.4)
  • Medium of choice for transport and preservation of V. cholera
  • Cary-Blair transport medium can be used to transport many bacterial enteric pathogens, including Shigella, Salmonella, and Vibrio cholerae

2. Amies’and Staurt’s transport media

  • Acceptable for Shigella and Salmonella (including ser. Typhi), but they are inferior to Cary-Blair for transport of V. cholerae.

3. Alkaline peptone water

  • This medium may be used to transport V. cholerae, but this medium is inferior to Cary-Blair and should be used only when Cary-Blair medium is not available.
  • It should not be used if subculture will be delayed more than 6 hours from the time of collection, because other organisms will overgrow vibrios after 6 hours.

4. Buffered glycerol saline (BGS)

  • It’s a liquid medium which can be used for Shigella but this transport medium is unsuitable for transport of V. cholerae.



Q. 7

Selective media for TB bacilli is:

 A

NNN media

 B

Dorset media

 C

LJ media

 D

Nutrient agar

Ans. B:C

Explanation:

Ans. (b) and (c) Dorset media and LJ media

Solid

Liquid

Lowenstein Jensen media (most widely used) Dubos contain Tween 80
Dorset egg media Middle Brook’s
Loeffler’s media Proskauer and Beck’s
Pawlowsky media Sula’s and Sautan
  • Selective agent inhibiting other bacteria in LJ media is Malachite green.
  • Human tubercle bacilli do not grow in presence of para-nitrobenzoic acid.
  • Traces of fatty acid is toxic for tubercle bacilli in culture media.
  • Optimum pH for M. tuberculosis: 6.4-7.0.

Other Options:

NNN media → For Leishmania donovani

Nutrient agar → Simple media

MacConkey media → Differential as well as indicator media for lactose and non-lactose fermenters.


Q. 8

A patient with acute onset of diarrhea comes to emer­gency. After culture on enriched media, colonies as shown below were visualized. Identify the causative organism:

 A Vibrio cholera

 B

Salmonella typhi

 C

Compylolacter jejuni

 D

E. coli 

Ans. A

Explanation:

Ans. is. ‘a’ i. e., Vibrio cholera



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