A dark pigmented colony is isolated from the leg wound of a fisherman from Florida. The gram-negative rod grows on sheep blood and MacConkey agars. The organism provides the following reactions:
TSI: K/A Indole: no color change Lysine: no color change
1 NaCL: no growth Arginine: purple Ornithine: no color change
DNase: pink halo around the area of organism inoculum
The microbiologist cannot read the oxidase reaction due to the dark pigment. What can he do to help achieve a valid oxidase reaction?
A) Grow the organism under anaerobic conditions and retest
B) Grow the organism on a non-nutrient agar and retest
C) The oxidase test is not necessary for the identification of this organism
D) Perform a modified oxidase test
Question 2
A microbiologist sets up a set of decarboxylase tubes for identification of a glucose fermenting, gram-negative rod.
After 24 hours, the tubes reveal
Base control: gray
Arginine: purple
Lysine: yellow
Ornithine: purple
These tubes should be interpreted as
A) all positive. B) positive for arginine and ornithine.
C) invalid. D) positive for lysine.
Florida box turtle Terrapene carolina
The Hartlaub's Duck (Pteronetta hartlaubii) is a dark chestnut-coloured duck of African forests
Indian paper wasp (Ropalidia) colony with eggs
Pigmented bands in nail of patient with dark skin