Question

What is gaseous requirement of positive motility test?

Answer 1

What is gaseous requirement of positive motility test?

ans:

A positive motility test is indicated by a diffuse zone of growth flaring from the line of inoculation.

A positive motility test is indicated by a pink color diffusing from the line of inoculation.

Gas bubbles were present at times in the motility media these could confound interpretation of motility and binding results or cause breakage at the interfaces of agar layers. However, refrigeration of tubes at 5°C (∼30 min) and/or gentle tapping of tubes on the bench top improved the reading of results since dissipation of the formed bubbles enabled visualization of bacterial growth boundaries.

the single-tube agar-based test system is that it is a contained test. After culturing for motility, there is no need for secondary handling of bacteria to conduct H7 serology. Additionally, the test avoids the difficulties of reading slide- or test tube-based agglutination reactions which require separate motility enhancement procedures. Bubbles that occasionally formed in motility test media were ascribed to the presence of fermentable sugar, which was metabolized during gas production. It is possible to reduce the bubbling phenomenon by constructing media devoid of a fermentable sugar carbon source.

The concern here is that gas gangrene may have taken hold in the dead tissue. The most likely agent of gas gangrene is Clostridium perfringens, an endospore-forming, gram-positive bacterium. It is an obligate anaerobe that grows in tissue devoid of oxygen. Since dead tissue is no longer supplied with oxygen by the circulatory system, the dead tissue provides pockets of ideal environment for the growth of C. perfringens.

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