Aseptic Technique – Inoculating Different Types of Media Key concepts: Different types of bacterial cultures: broth, agar slant, and agar deep. Aseptic transfer of bacteria from one type of culture medium to another. Appropriate use of inoculating loops and needles.

Four Basic Forms of Bacterial Culture Media Agar plate Broth Agar Deep Agar Slant Four Basic Forms of Bacterial Culture Media

Always use sterile instruments to transfer bacteria! Loop and Needle

Flame loop before AND after using it

Other Sterile Transfer Instruments

“Little Finger Technique”

....so far provided to us: NB or TSB

Today: You Inoculate Fermentation Tubes (G and L) Contain: Peptones and NaCl COH of interest (0.5 – 1%) Phenol red indicator ( alternate name “phenol red broth or PR broth”) Used to differentiate Enterobacteriaceae among themselves and from other Gram-neg. rods.

....so far provided to us: NA or TSA slant cultures From left to right: Micrococcus luteus, Pseudomonas aeruginosa, E. coli

Today: You Inoculate Urea Agar Slants Contain: Peptones, glucose and potassium phosphate (as buffer to resist alkalinization due to peptone metabolism) Urea Phenol red

Also today: Use the Inoculating Needle to inoculate an agar deep the end