1.3.4: Inoculating Tools

Inoculating Loop -

Figure 1. Inoculating loop. Credit: Sherry Smith

An inoculating loop is the most common inoculating tool used in the microbiology laboratory. Inoculating loops exist in several types, including metal loops that may be reused and plastic sterile loops that are disposed of after use. Inoculating loops are frequently used in the transfer of bacteria from one type of media to another, such as broth to broth, broth to slant, or broth to agar.

Loops can also be used for the streak plate isolation method and for transferring samples to microscope slides to create a smear.

Inoculating Needle -

Figure 2. Inoculating needle. Credit: Sherry Smith

Inoculating needles are similar to loops in the way they are made, with the exception of a straight wire in place of the circular loop at the end. Like inoculating loops, they may be made of metal or plastic. Inoculating needles are used for stabbing media, as is needed in motility tests, or for obtaining very small colonies from solid media for transfer.

Glass Spreading Rod -

Figure 3. Glass spreading rod. Credit: Sherry Smith

Glass spreading rods, also called glass spreaders, are glass rods that have been bent into an L-shape. They appear much like a hockey stick and are used to spread an inoculum over the surface of a solid medium. The isolation technique known as the spread plate technique makes use of a glass spreading rod.