The role of oxidase reagents

Most people don't know much about oxidase reagents. In fact, oxidase reagents are a kind of chemical product. We rarely use them in daily life. Generally, oxidase reagents are often used as tests for Campylobacter jejuni and are also used as identification culture media. They are generally used to distinguish culture media for different microorganisms. Although we don't often see oxidase reagents, there is no harm in knowing about them.

The oxidase test is a test based on the principle that the oxidase does not react directly with the oxidase reagent, but first oxidizes cytochrome C, and then the oxidized cytochrome C oxidizes p-phenylenediamine to produce a color reaction. The results of this test are related to the presence of cytochrome C.

Used for identification of Neisseria species, all bacteria of this genus are positive. In addition, it is also used to distinguish between Pseudomonas and Enterobacteriaceae, the former being positive and the latter being negative. Moraxella, Alkali-producing Bacillus, etc. were all positive.

Abnormal results: Neisseria species include 9 pathogenic bacteria such as Neisseria meningitidis and Neisseria gonorrhoeae, which cause epidemic cerebrospinal meningitis

Upper respiratory tract symptoms: nasopharyngitis and other systemic infection symptoms: high fever, bleeding spots or ecchymosis, meningitis symptoms: headache, vomiting, stiff neck; cause gonorrhea, cause neonatal gonorrheal conjunctivitis.

People who need to be checked: Those with the above symptoms

Precautions

① Avoid contact with iron-containing substances during the test to avoid false positives. ② 10g/L tetramethyl-p-phenylenediamine hydrochloride or 10g/L tetramethyl-p-phenylenediamine hydrochloride aqueous solution is a colorless solution, which is easily oxidized and ineffective in the air. Therefore, new reagents should be replaced frequently and stored in brown bottles. If the reagent has turned dark blue, it should be discarded.

Unsuitable people: None

Taboos before examination: Pay attention to normal living and eating habits and personal hygiene.

Requirements during the examination: Actively cooperate with the doctor

Inspection process

Reagents: 1g tetramethyl-p-phenylenediamine hydrochloride, 100ml water (stored in a brown bottle and kept in the refrigerator for 2 weeks)

method:

(1) Take a piece of filter paper and dip it into a small amount of the test bacterial colony. Then add a drop of tetramethyl-p-phenylenediamine reagent, just moisten the filter paper, not too wet. If red appears within 10 seconds, it is positive. If red appears between 10 and 60 seconds, it is a delayed reaction. If red appears after 60 seconds, treat it as negative. Iron can catalyze the reagent and cannot be used. Platinum wire or glass rod can be used to remove the bacteria.

(2) Wet the filter paper with 1% tetramethyl-p-phenylenediamine solution, then add an equal amount of 1% naphthol solution (1g naphthol, 100ml alcohol). Then, smear the bacterial moss. If a blue color appears, it is a positive reaction. The time for the color to appear is the same as method 1.

(3) Soak Xinhua No. 1 filter paper with 1% tetramethyl-p-phenylenediamine solution, air-dry it indoors, and place it in a dark bottle with a rubber stopper. It can be stored in the refrigerator for several months. If it is stored for too long, the color will be too dark and the color will not be obvious, so it should not be used. Same usage as before.