Question

based on these results are these positive or negative

Order of Tubes in the Rack Motility/Oxygen Usage Growth at 4C Growth at 6.5% NaCl Lactose Mannitol VP I

its an unknown bacteria

Answer 1

Motility/Oxygen usage-
By observing results of this test , it indicate that test is negative , because growth is observed but that is confined to the stab line with sharp margins and surrounding medium is transparent.
Positive test observed as diffuse growth away from stab line of inoculation, turbidity or cloudiness.

Growth at 4 degree celcius-
By observing test result it can interpreted that organism able to grow at that temperature as turbidity is observed.

Growth at 6.5% NaCl-
In observing test result , the unknown organism is not able to grow at 6.5% NaCl as no turbidity observed, media is transparent or clear indicates test is negative.

Lactose-
Result of test indicates that test is positive as colour of medium changed to yellowish indicating pH change to acidic and also bubble is observed in inverted Durham's tube indicating gas production by inoculated organism. Organism is able to ferment lactose (acid production) and also gas production.

Mannitol-
Given result indicate that test is negative as no growth and colour of phenol red is also not changed therefore no acid production. No bubble formation in inverted Durham's tube therefore no gas production.

VP ( Voges Proskauer)-
Test result indicates test is negative as there is no cherry red colour formation which is positive result, there is formation of yellow brown colour indicate negative result.