Growth at 42°C Test- Principle, Procedure and Result Interpretation

Growth at 42°C Test- Principle, Procedure and Result Interpretation

Growth at 42°C Test- Principle, Procedure and Result Interpretation

Purpose of Growth at 42°C Test

This test is used to differentiate a pyocyanogenic pseudomonads from other Pseudomonas sp.

Principle of Growth at 42°C Test

The test is used to determine the ability of an organism to grow at 42°C. Several Pseudomonas species have been isolated in the clinical laboratory that are capable of growth at elevated temperatures.

Procedure of Growth at 42°C Test

  1. Inoculate two tubes of trypticase soy agar (TSA) with a light inoculum by lightly touching a needle to the top of a single 13- to 24-hour-old colony and streaking the slant.
  2. Immediately incubate one tube at 35°C and one at 42°C.
  3. Record the presence of growth on each slant after 18 to 24 hours.

Result Interpretation of Growth at 42°C Test

Positive: Good growth at both 35°and 42°C.
Negative: No growth at 42°C, but good growth at 35°C.

Quality Control

Positive: Pseudomonas aeruginosa (ATCC10145)
Negative: Pseudomonas fluorescens (ATCC13525)

Growth at 42°C Test- Principle, Procedure and Result Interpretation

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