Clear chromogenic urinary tract infection medium uses colour to differentiate between enterococci, Escherichia coli, coliforms, Staphylococcus aureus and organisms with tryptophan deaminase activity
Oxoid has launched a new chromogenic medium that is designed to enhance the presumptive identification of the main organisms responsible for urinary tract infections.
Oxoid clear chromogenic urinary tract infection (UTI) medium uses colour to differentiate between enterococci, Escherichia coli, coliforms, Staphylococcus aureus and organisms with tryptophan deaminase activity (TDA), such as Proteus, Morganella and Providencia spp.
The background is clear, allowing easy tie-up between sample and identification on multiple-sample plates.
By providing this specific and easily-visualised differentiation on a single culture plate, Oxoid clear UTI medium reduces the need for sub-culturing and further lengthy identification procedures, even when more than one species is present in the sample.
Oxoid clear chromogenic UTI medium contains two specific chromogen substrates.
One is cleaved by b-glucosidase in enterococci, resulting in blue colonies, and the other is cleaved by b-galactosidase in E coli, resulting in pink colonies.
Since coliforms have the ability to cleave both chromogens, they produce purple colonies.
In addition, tryptophan in the medium allows for the detection of TDA activity, causing such colonies to be brown in colour, while Staphylococcus aureus colonies retain their typical appearance.
