Thio broth- Lab

During lab this week, we have used THIO broth to inoculate and gram stain the organsisms. I am not very familiar with THIO broth, so i decided to do some research on it.

Thioglycollate Broth (THIO) is an enriched liquid medium for the growth of microaerophilic and anaerobic bacteria, including fastidious organisms, isolated from clinical specimens. It is an excellent growth medium for most sporeforming and non-sporeforming anaerobes

Thioglycolate broth contains Sodium thioglycolate, a reducing agent that creates anaerobic conditions when it reduces molecular oxygen to water. Dyes such as resazurin or methylene blue are usually added to the broth to provide a visual indication of the presence of oxygen. Resazurin is pink when oxidized and colorless when reduced. Methylene blue is blue when oxidized and colorless when reduced. A small amount of agar is added to slow the diffusion of oxygen within the media.  A marble chip (calcium carbonate) is added to the medium to provide additional pH buffering capacity and a constant supply of carbon.

Both facultative anaerobes and aerotolerant anaerobes will grow throughout the tube; however, facultative anaerobes will grow most densely where oxygen is present.

Another similar product, Campylobacter Thioglycollate Broth (CAMPY-THIO), is used as a selective growth enrichment broth for Campylobacter species from contaminated sources. The main difference is the thioglycolate basal medium is supplemented with antibiotics from the Blasar’s formulation and the concentration of Polymyxin B has been increased to prevent overgrowth of other bacteria.