Which of the following techniques CANNOT be used when performing the oxidase test?

The oxidase test is a diagnostic technique used to identify bacteria that produce the enzyme cytochrome c oxidase. When performing the oxidase test, it is crucial to avoid any materials that may interfere with the reaction of the reagent. Using a nichrome loop involves a metal that can potentially react with the oxidase reagent, leading to false-positive results.

In contrast, transferring a colony using a sterile wooden stick is appropriate, as wooden sticks do not interfere with the oxidase reagent. Swabbing with a colony on the oxidase reagent is also a standard practice, as it allows for the direct interaction between the reagent and the bacterial enzymes present. Inoculating a broth culture may be part of a further testing protocol but does not directly pertain to the oxidase test itself, making it a less relevant method in the context of this specific test's requirements.

Thus, the use of a nichrome loop is identified as the option that cannot be used for the oxidase test due to the risk of reaction interference.